DEVELOPMENTS AT ELEVENTH INTERNATIONAL
CONFERENCE ON WATER POLLUTION RESEARCH
Cape Town, South Africa
March 29 - April 2,1982
Prepared For
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C.
By
United States of America National Committee
for Representation of the United States to the
International Association on Water Pollution Research and Control
December 1982
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DEVELOPMENTS AT ELEVENTH INTERNATIONAL CONFERENCE
ON WATER POLLUTION RESEARCH
Cape Town, South Africa
March 29 - April 2, 1982
by
United States of America National Committee
for Representation of the United States to the
International Association on Water Pollution Research and Control
EPA Grant No. R809703-01-1
Donald E. Carey
Project Officer
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C.
December 1982
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DISCLAIMER
This report was published as prepared by The Grantee.
The contents do not necessarily reflect the views and policies
of the U.S. Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement
or recommendation for use.
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\M
UNITED STATES OF AMERICA NATIONAL COMMITTEE
FOR REPRESENTATION OF THE UNITED STATES TO THE
INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH & CONTROL
CHAIRMAN.
OR. FRED G. PCHJVC (AEEP)
SCHOOL OF CIVIL ENGIfCERING
GEORGIA INSTITUTE OF TEONOLOGY
ATLANTA, GEORGIA 30332
(404) 894-2265
VICE-CHAIRHftNi
OR. RICHARO S. ENGELBREOHT (WPCF)
3230 CIVIL ENGINEERING BLOG.
O^IV. OF ILLINOIS 9 lflBANA-04A*FA!GN
206 NORTH ROMIhE STREET
iraANA, ILLINOIS 62601
(217) 333-3622
SECRETARY-TREASURER.
M?. RICHARD A. CONWAY (ASCE)
RESEARCH t DEVELOPMENT OEPART>€NT
IN I ON CARBIOE CORPORATION
P. 0. BOX 8361 <770-3*2>
SOUTH CHARLESTON, WEST VIRGINIA 29303
(304) 747-4016
February 10, 1983
Mr. Donald E. Carey
Science Review Administrator
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
Re: EPA Grant No. R809703-01-1
Dear Mr. Carey:
In accordance with the provisions of EPA Grant No. R809703-01-1, awarded
to the United States of America National Committee (USANC) for representa-
tion of the U.S. to the International Association on Water Pollution
Research and Control (IAWPRC), USANC is pleased to transmit this report
entitled "Developments at Eleventh International Conference on Water
Pollution Research". Included in this report are reviews of the Poster
Sessions and interpretive analyses of informal developments at the
Conference which were judged to be of particular relevance to water quality
control activities in the U.S. A total of thirty-four (34) engineers and
scientists from the U.S. contributed in some way to the preparation of
this report.
The purpose of the EPA Grant, resulting in this report, was to provide a
mechanism whereby current water research developments from around the
world could be highlighted and brought to the attention of the EPA Office
of Research and Development and other U.S. water pollution researchers.
Specifically, this report is not simply a collection of papers presented
at the Conference in Cape Town, South Africa, March 29 - April 12, 1982,
or merely an abstract or synopsis of papers, but rather an analysis of
formal and informal developments, including pertinent remarks, comments
and ideas brought out in discussions of papers and with researchers from
throughout the world; representatives from twenty-nine (29) different
countries attended the Conference. The formal papers and discussions of
the Conference are published as Proceedings in Water Science and Technology.
SPONSORING ORGANIZATIONS
ASSOCIATION OF ENVIRONMENTAL ENGIKEERING PROFESSORS AMERICAN CHEMICAL SOCIETY
AfCRICAN INSTITUTE OF CHEMICAL ENGINEERS AMERICAN SOCIETY OF CIVIL ENGINEERS WATER POLLUTION CONTROL FEDERATION
12TH BIEWIAL INTERNATIONAL CONFERENCE, AMSTERDAM. NETHERLANDS, 17-20 SEPTEMBER 1961
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Mr. Donald E. Carey
Page 2
February 10, 1983
The members of USANC sincerely appreciate the support provided by the
Office of Research and Development for the preparation of this report.
Should there be any questions or need for additional information, please
feel free to contact any member of the Coordinating Subcommittee.
J "i nroro 1 v/
for USANC Coordinating Subcommittee
R. S. Engelbrecht
R. A. Conway
D. G. Stephan
F. G. Pohland, Chairman
hb
Attachment
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CONTENTS
Page
LETTER OF TRANSMITTAL iii
KEY TO REVIEWS viii
EXECUTIVE SUMMARY xix
I. INTRODUCTION 1
II. CONFERENCE SESSION REPORTS 5
Monitoring Systems and Strategies, Buoyant Jets,
Taste and Odors 5
Paper Nos. 1, 4, 7, 10, 13
Reviewer: Betty H. Olson
Water Quality Management 24
Paper Nos. 16, 18, 20, 22
Reviewer: Edward J. Massaro
Microbial Resistance; Wastewater Ozonation;
Wastewater Phenol ics 38
Paper Nos. 24, 26, 28, 30
Reviewer: P. V. Scarpino
Assessment and Control Strategies for Water Quality
Management 46
Paper Nos. 32, 34, 36, 38
Reviewer: A. J. Englande, Jr.
River Water Quality; Sediment-Water Interactions 55
Paper Nos. 40, 42, 44, 46
Reviewer: Gerard A. Rohlich
Concentration Techniques for Viruses in Water 64
Paper Nos. 48, 50, 52, 54
Reviewer: Ronald D. Neufeld
Disinfection; Surface Water Quality 73
Paper Nos. 56, 58, 60, 62
Reviewer: Joseph P. Gould
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Page
Biological Waste Treatment, Sludge Incineration
and Rheology 80
Paper Nos. 2, 5, 8, 11, 14
Reviewer: William C. Boyle
Desalination and Filtration 92
Paper Nos. 17, 19, 21, 23
Reviewer: Edward S. K. Chian
Mass Transfer; Scale Up and Mathematical Modeling.... 101
Paper Nos. 25, 27, 29, 31
Reviewer: Dipak Roy
Physical/Chemical Waste Treatment and Metal Removal.. 114
Paper Nos. 33, 35, 37, 39
Reviewer: David Jenkins
Wastewater Treatment 119
Paper Nos. 41, 43, 45, 47
Reviewer: Foppe B. DeWalle
Sludge Treatment and Disposal 124
Paper Nos. 49, 51, 53, 55
Reviewer: Alan H. Molof
Biological Nitrification and Denitrification 142
Paper Nos. 57, 59, 61, 63
Reviewer: Paul L. Bishop
Wastewater Impacts and Uses for Water Supplies 152
Paper Nos. 3, 6, 9, 12, 15
Reviewer: Julian B. Andelman
The Use of Mathematical Models (Theme 1) 162
Reviewer: Philip J. W. Roberts
Oil Pollution in Marine and Freshwater Environments
(Theme 2) 179
Reviewer: Lawrence H. Keith
The Economics of Water Pollution Control and
Research (Theme 3) 185
Reviewer: Carmen F. Guarino
Technology Transfer (Theme 4) 189
Reviewer: Aharon Netzer
Water Pollution Control in Developing Areas
(Theme 5) 198
Reviewer: Kazuyoshi Kawata
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Page
Water Recycling (Theme 6) 207
Reviewer: Richard D. Heaton
Water Quality Problems Caused by Toxic, Nuisance,
and Nutrient Chemicals 217
Poster Presentation Nos. SI,83,514,515,518,523
Reviewer: Clifford W. Randall
Effects of Pollutants on Receiving Waters 226
Poster Presentation Nos. S16,S19,S20,S24,S30
Reviewer: Herbert C. Preul
Oil Spills and Environmental Pollution 231
Poster Presentation Nos. S7,S8,S9,S10,S28,S29
Reviewer: Thomas H. Goodgame
Wastewater Treatment 234
Poster Presentation Nos. S2,S17,S23,S32,S33,S34
Reviewer: Robert A. Canham
Wastewater Treatment 237
Poster Presentation Nos. S35,S36,S37,S38,S39,S40
Reviewer: K. Daniel Lindstedt
Wastewater Treatment and Reclamation 245
Poster Presentation Nos. S5,S6,S21,S26,531
Reviewer: Bruce A. Bell
Membrane Processes; Environmental Microbiology 250
Poster Presentation Nos. S4,S11,S12,S27
Reviewer: George Belfort
III. OVERVIEW OF PERTINENT CONFERENCE DEVELOPMENTS 253
Developments at Formal Sessions 253
Developments Outside of Formal Sessions 264
APPENDICES
I. PROGRAMME: 11th Conference of the Inter-
national Association on Water Pollution
Research (IAWPR) 282
II. Memorandum: Development of Report for EPA on
IAWPR Cape Town Conference 306
III. Assignments—Participants in USANC Project 310
IV. Memorandum: Assignments for Development of
USANC Report on Cape Town Conference 312
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KEY TO REVIEWS
Number Title and Authors Page
PAPERS
1. The Effect of Submarine Wastewater Discharge
on the Bacterial Quality of Surf Waters 5
D. J. Livingstone (South Africa)
2. ¦ The Effect of Aeration Basin Configuration on
Activated Sludge Bulking at Low Organic
Loading 80
5. E. Lee, B. L. Koopman, D. Jenkins,
R. F. Lewis (U.S.A.)
3. Development of Water Reclamation Technology in
South Africa 152
A. J. Clayton, L. R. J. van Vuuren,
B. Roux (South Africa)
4. Surface Dilution of Round Negative Buoyant
Jets--A Comparison with Other Jets 9
6. Noutsopoulos, J. Demetriou (Greece)
5. Obtaining Secondary Treatment with RBC
Underflow Clarifiers 83
I. L. Bogert (U.S.A.)
6. Removal of Potential Carcinogens and Toxicants
by Treatment Systems for Direct and Indirect
Reuse of Wastewater Evaluated by Means of a
Hamster Cell Culture Assay 154
R. Kfir, 0. W. Prozesky (South Africa)
7. The Distribution and Significance of Toxic
Metals in Sharks from the Natal Coast, South
Africa 10
R. J. Watling, H. R. Watling,
R. C. Stanton, T. P. McClurg,
E. M. Engelbrecht (South Africa)
8. Optimization of Nitrogen Removal in the
Single Sludge Activated Sludge Process 84
A. C. van Haandel, P. L. Dold,
G. v. R. Marais (South Africa)
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Number Title and Authors Page
9. Organic Micropollution of Potable Water
Supplies—Indirect versus Direct Reuse 156
J. F. J. van Rensburg, S. J. Theron,
A. J. Hassett, P. G. van Rossum
(South Africa)
10. Baseline Studies and Continuous Monitoring
for a Shallow Tropical Bay Receiving Nickel
Refinery Effluent 14
J. E. Carey, M. A. Pettit, W. S. Rooney,
T. L. Judell (Australia)
11. Fate of Heavy Metals and Potential for
Clinker Formation During Pilot Scale
Incineration of Municipal Sludge 87
H. W. Campbell, P. J. Crescuolo,
T. R. Bridle (Canada)
12. The Economic Impact on an Urban Industrial
Complex of Mineral Pollution in the Water
Supply--A Case Study 157
J. J. C. Heynike, S. F. McCulloch
(South Africa)
13. Influence of Discharges from Storage Reservoirs
on the Tastes and Odours Appearing in the Seine
and Marne Rivers 18
M. Rizet, J. Mouchet (France)
14. The Use of Rheology for Sludge Characterization 88
H. W. Campbell, P. J. Crescuolo (Canada)
15. Limnological Effects of the Elimination of
Phosphorous from the Wahnback Reservoir 158
H. Bernhardt, J. Clasen (Federal
Republic of Germany)
16. New Methods for Analysing Water Pollutants 24
L. H. Keith, R. C. Hall, R. C. Hanisch,
R. G. Landolt, J. E. Henderson (U.S.A.)
17. Slow Sand Filtration for Cercarial Control in
North Cameroon Village Water Supply 92
K. Kawata (U.S.A.)
18. Simultaneous in Determination of Dissolved
Gases by Gas Chromatography: II Oxygen and
Nitrogen in Activated Sludge Process Streams... 28
T. Bilstad, E. N. Lightfoot (Norway, U.S.A.)
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Number Title and Authors Page
19. Characterization of Fouling Potential for
Pressure-Driven Membrane Processes: A New
Simulated Flow Cell 94
R. H. Reed, G. Belfort (U.S.A.)
20. Nutrients Removal and Recovery in a Two-Stage
High-Rate Algal Wastewater Treatment System... 31
G. Shelef, U. Azov, R. Moraine (Israel)
21. Desalination by Continuous Ion Exchange
Based on Thermally Regenerable Magnetic
Microresins 96
B. A. Bolto, E. A. Swinton (Australia)
22. Operational Management of Pollution Incidents-
The Thames Way, UK 35
E. C. Reed, M. C. Dart (United Kingdom)
23. Continuous Counter-current Ion Exchange for
Desalination and Tertiary Treatment of
Effluents and Other Brackish Waters 98
B. A. Hendry (South Africa)
24. Viability and Adaptability of E. Cote and
Enterococcus Group to Salt Water with High
Concentration of Sodium Chloride 38
T. Omura, M. Onuma, Y. Hashimoto (Japan)
25. On the Mass-Transfer Characteristics Within
Microbial Systems 101
M. Onuma, T. Omura (Japan)
26. Chlorine-Resistance of Coliform-tested
Bacteria Isolated from Raw and Treated Sewage
Effluents 41
L. Y. C. Leong, D. Otsaka, H. F. Ridgway,
B. H. Olson (U.S.A.)
27. The Scale-up and Limitation of Physical
Oxygen Transfer in Rotating Biological
Contactors 103
B. J. Kim, A. H. Molof (U.S.A.)
28. Ozonation of Aromatic Compounds: pH-Dependence. 42
E. Gilbert (Federal Republic of Germany)
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Number Title and Authors Page
29. Application of the Marais-Ekama Activated
Sludge Model to Large Plants 106
H. A. Nicholls (South Africa)
30. Presence of Phenolic Compounds in Sewage,
Effluent and Sludge from Municipal Sewage
Treatment Plants 43
F. B. DeWalle, D. A. Kalman, D. Russell,
D. Norman, E. S. K. Chian (U.S.A.)
31. A Mathematical Model of Biological Purification
in Aerated Activated Carbon BiofiIters 109
G. Martin, A. Y. le Roux, P. Schulof
(France)
32. An Appraisal of the Performance of a Continuous
Automatic Fish Biomonitoring System at an
Industrial Site 46
W. S. G. Morgan, P. C. Kuhn, B. Allais,
G. Wall is (South Africa)
33. Granular Activated Carbon and Preozonated
Granular Activated Carbon Treatment for
Biologically and Physically-Chemically
Treated Wastewater Effluents 114
A. Netzer, J. L. McNutt (U.S.A.)
34. Examination of a Drinking-water Supply for
Mutagenicity 48
P. G. van Rossum, J. M. Willemse,
C. Hilner, L. Alexander (South Africa)
35. The Nature of the Reactions Between Chlorine
and Purine and Pyrimidine Bases: Products &
Kinetics 1 115
J. P. Gould, T. R. Hay (U.S.A.)
36. Depositional Process of Fine Sediments 50
T. Kusuda, T. Umita, K. Koga, H. Yorozu,
Y. Awaya (Japan)
37. The Fate of Some Metal Species: Lead, Cadmium,
Zinc in Surface Water During Biological Sand
Filtration—Effects of Preozonation H°
F. Erb, D. Delabre, J. C. Hopitault,
A. Philippo, P. Thomas, A. Brice (France)
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Number Title and Authors Page
38. Nutrients and Algal Growth in an Impounded
River. Consequences for its Oxygen Balance
and Nutrient Control Strategy 51
K. R. Imhoff, D. R. Albrecht (Federal
Republic of Germany)
39. A New Configuration of the High-Lime Process
with Sludge Recirculation for Magnesium
Recycling 117
E. Idelovitch, A. M. Wachs (Israel)
40. Impact of Nuclear Power Plants of the PWR-type
on River Water Quality 55
W. J. Masschelein, J. Genot (Belgium)
41. An Integrated Low Cost System for Treatment
of Potato Processing Wastewater Incorporating
Anaerobic Fermentation and Phosphorus Removal. 119
J. G. Parker, B. J. Lyons, C. D. Parker
(Australia)
42. Fractional Composition of Phosphorus Forms in
Sediments Related to Release 57
H. Furumai, S. Ohgaki (Japan)
43. The Adsorption Behaviour of Cationic
Polyelectrolytes in Dissolved Air Flotation... 119
R. Gehr, J. G. Henry (Canada)
44. The Influence of Sediment Water Interactions
in an Impoundment on Downstream Water Quality 58
T. J. Grizzard, C. W. Randall,
E. M. Jennelle (U.S.A.)
45. The Performance of an Ultrafiltration Pilot-
plant for the Closed Loop Recycling of
Textile Desizing Effluents 120
C. A. Buckley, R. B. Townsend,
R. Groves (South Africa)
46. River-Basin Planning for Control of Nitrate
Pollution 60
C. S. Sinott, D. G. Jamieson (United
Kingdom)
47. Leaching Characteristics of Industrial Metal
Finishing Wastewater Treatment Plant Solids... 120
T. H. Goodgame, P. W. Barnett (U.S.A.)
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Number Title and Authors Page
48. Virus Removal by Filtration 64
N. Sriramulu, M. Chaudhuri (India)
49. Aerobic Thermophilic Stabilization of Sludge
Versus Anaerobic Digestion and Other Kinds
of Sludge Treatment at Middle-sized Plants
with Respect to Power Conservation and
Economy 124
P. Wolf (Federal Republic of Germany)
50. Enterovirus Concentration using Automated
Hollow Fiber Ultrafiltraton 66
G. Belfort, A. Paluszek,
L. S. Sturman (U.S.A.)
51. Simultaneous Pasteurisation-Digestion (SPD-
Process) 126
G. Kugel (Federal Republic of Germany)
52. A Comparative Study of Methods for Concentra-
tion of Human Enteroviruses 68
M. T. Martins, E. Marques, L. A. Soares
(Brazil)
53. Inhibition Modelling in Anaerobic Digestion 130
A. C. Duarte, G. K. Anderson (Portugal,
United Kingdom)
54. A New Large Scale Technique for Quantitative
Recovery of Enteroviruses by Adsorption on
Suspended Glass Powder, Application to
Surface and Drinking Waters of the Paris Area.. 69
P. H. Vilagines, B. Sarrets, C. Danglot,
R. Vilagines (France)
55. Process Integration in Sludge Management 135
R. I. Dick, D. L. Simmons, Y. Hasit
(U.S.A.)
56. Ozone as a Sterilising Agent, Its Advantages
and Disadvantages in the Treatment of Water 73
M. Schalekamp (Switzerland)
57. Elements of the Inhibition of Nitrifying
Bacteria 142
G. Martin, Y. Richard (France)
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Number Title and Authors Page
58. The Mechanism of Ozone Inactivation of Water
Borne Viruses 74
0. J. Sproul, R. M. Pfister, C. K. Kim,
(U.S.A., Korea)
59. Biological Nitrification in an Up-flow Fixed
Bed Reactor (UFFBR) 144
G. M. Faup, A. Leprince, M. Pannier
(France)
60. Predicted Changes in Water Quality after
Elimination of Storm Runoff into the Urban
Lake and Canals of Hamburg 75
H. Caspers (Federal Republic of Germany)
61. Simulation of Nitrification and its Dynamics
in a Rotating Biological Contactor 146
Y. Watanabe, H. E. Bravo, K. Nishidome
(Thailand, Japan)
62. Quality and Quantity of Stormwater Runoff
from a Commercial Land-Use Catchment in
Natal, South Africa 77
D. E. Simpson, P. H. Kemp (South Africa)
63. Effect of Denitrification on the pH in
Biofilms 149
E. Arvin, G. H. Kristensen (Denmark)
WORKSHOPS
1. The Use of Mathematical Models (Theme 1) 162
2. Oil Pollution in Marine and Freshwater
Environments (Theme 2) 179
3. The Economics of Water Pollution Control and
Research (Theme 3) 185
4. Technology Transfer (Theme 4) 189
5. Water Pollution Control in Developing Areas
(Theme 5) 198
6. Water Recycling (Theme 6) 207
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Number Title and Authors Page
POSTER PRESENTATIONS
51 Removal of Pesticides and Herbicides by Means
of Adsorption on Activated Carbon 217
D. V. Heroes (Belgium)
52 Computer Control in a Sewage Plant, Methods
and Experience 234
C. P. Kuznia (Federal Republic of Germany)
53 Adsorption and Biodegradation of Linear Alkyl-
benzene Sulfonates (LAS) by Activated Sludge.. 218
K. Yoshimura, A. Nakae (Japan)
54 The Application of Pre-Treatment Procedures to
Limit Membrane Fouling in Reverse Osmosis
Reclamation of Secondary Sewage Effluents 250
H. A. de Villiers, G. R. Botha,
M. H. Wright (South Africa)
55 ' Flotation as the Final Clarification Step in
Wastewater Treatment and its Influence on the
Oxygen Balance of Receiving Waters 245
K. P. Kiefhaber, U. Neis, J. Weber
(Federal Republic of Germany)
56 The Disposal of Sewage Sludge by Land
Spreading 246
J. H. Nell, J. F. P. Engelbrecht
(South Africa)
57 Total Mercury Concentrations in Some Species
of South African Commercial Marine Fish 231
J. Henry (South Africa)
58 Toxicity Testing of South African Oil-Spill
Dispersants 231
A. Moldan, P. Chapman (South Africa)
59 Effect of Oil on Reproductive Capacity of
CalLuinaAAa Kaaum-l 232
L. F. Jackson (South Africa)
S10 The Use of Ultraviolet Absorption in the
Measurement of Fish-Factory Pollution 232
P. Chapman (South Africa)
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The Survival of Bacterial Indicators in
Lysimeters and Landfills
J. A. Donnelly, P. V. Scarpino
D. Brunner (U.S.A.)
Effect of Ionic Presence on Chlorine Disin-
fection of Animal Viruses
S. Cronier, P. V. Scarpino,
C. Wells (U.S.A.)
Interactive Water Quality Simulation of the
Han River using Computer Graphics
Y. Chung, P. N. French,
P. Loucks (Korea, U.S.A.)
Polyelectrolyte Toxicity Tests by Fish
Avoidance Studies
L. D. Spraggs, R. Gehr,
J. Hadjinicolaou (Canada)
Mineralisation Problems in the PWV Complex--
The Identification of Viable Solutions by
Means of a Suite of Deterministic Models
C. E. Herold (South Africa)
A Chemical Investigation of a Marine Sewage
Outfall
P. D. Bartlett, G. A. Eagle (South
Africa)
The Location and Nature of Accumulated
Phosphorous in Activated Sludge
L. Buchan (South Africa)
Microbiology of Nutrient Removing Activated
Sludge
Margaret A. Hart, Leah N. Melmed
(South Africa)
Nutrient-Salinity Relationships in Four
Estuaries of the Cape Province, South Africa.
G. A. Eagle, P. D. Bartlett (South Africa)
The Role of DOC and TOH Measurements in Water
Pollution
R. A. van Steenderen (South Africa)
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Number Title and Authors Page
521 Aspects of the Performance of Final Clarifiers
in the Activated Sludge Process 247
C. Davies (South Africa)
522 Flux of Cadmium through a Laboratory Food Chain
(Media-algae-mussel) and its Effects *
H. F. K. 0. Hennig, M. J. Orren
(South Africa)
523 Influence of Sewage Irrigation on the
Groundwater Quality 235
G. Milde, H. Dizer, Z. Filip,
V. Newmayer, V. Paibyl
524 The Impact of Diffuse Atmospheric Nutrient
Loading on an Oligotrophic Freshwater Lake in
a Developing Urban and Industrial Area
(Richards Bay, South Africa) 229
C. G. S. Archibald, M. S. Muller
(South Africa)
525 Interstitial Meiofauna as Indicators of Sandy
Beach Pollution 220
T. P. McClurg (South Africa)
526 Production of Algal Protein in Raw Sewage 247
J. M. P. Viviers, E. Sandbank,
L. R. J. van Vuuren, A. Gerber (South
Africa)
527 The Enumeration of Streptococci and Mycobac-
teria Present in Landfill Leachate 251
J. A. Donnelly, P. V. Scarpino,
D. B. Brunner (U.S.A.)
528 Some Aspects of the Sensitivity of Juvenile
Jcuu6 Lalandli to the Water Soluble Fraction
of Crude Oil 232
S. R. Lipschits (South Africa)
529 Ecotoxicological Evaluation of an Oil Gelling
Agent--its Effect on Photosynthesis of Seaweed 232
T. Yoshida, T. Maruyama, H. Kojima
(Japan)
530 The Measurement of Organic Pollution of the
Sea Using Satellite Imagery 230
L. V. Shannon, N. M. Walters,
A. G. S. Moldan (South Africa)
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Number Title and Authors Page
531 Exhaustive Recyclic Use of Water in the Food
Industries 248
R. A. Gallop, A. W. Hydamaka, B. J. Clark,
L. B. Carvalho (Canada)
532 Precipitation of Calcium Phosphate and pH-
effects in Denitrifying Biofilms 235
E. Arvin, G. H. Kristensen (Denmark)
533 Biochemical Changes Associated with Luxury
Phosphate Uptake in a Modified Phoredox
Activated Sludge System 235
D. J. J. Potgieter, B. W. Evans
(South Africa)
534 L.F.B.--Full Scale Operation 235
D. S. Render (South Africa)
535 Suppression of Density Waves in Clarifiers 237
M. C. Murphy, R. R. Hudgins,
P. L. Silveston (Canada)
536 Parasites in Southern United States Sludges
and Disinfection by Standard Sludge Treatment. 237
R. S. Reismers, M. D. Little,
A. J. England, D. B. Leftwich,
D. D. Bowman, R. F. Wilkinson (U.S.A.)
537 Water and Wastewater Treatment with Reusable
Magnetite Particles 238
N. J. Anderson, B. A. Bolto, D. R. Dixon,
L. 0. Kolarik, A. J. Priestley,
W. G. C. Raper (Australia)
538 A System Developed for the Treatment of
Tanning and Fellmongery Effluents 239
S. D. Roets (South Africa)
539 Research into the Mass Culture of Algae in
Closed Systems 240
R. D. Walmsley, S. N. Shillinglaw,
D. Geldenhuys (South Africa)
540 Utilization of Computerized Water Monitoring
and Information System 240
E. Ottmann (Federal Republic of Germany)
*Note: This presentation was included in the program but was not
presented at the Conference. It is not included in this report.
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EXECUTIVE SUMMARY
Beginning in 1962, the International Association on
Water Pollution Research and Control has held an international
conference biennially. This report is an interpretative analysis
of formal and informal developments at the Eleventh International
Conference on Water Pollution Research held in Cape Town, South
Africa on March 29 to April 2, 1982 and has been prepared for
the U.S. Environmental Protection Agency by the U.S.A. National
Committee for Representation of the United States to the Inter-
national Association on Water Pollution Research and Control.
Conference papers, complete with formal and informal
floor discussion, are published in WouteA Scu.&nc
-------
the roles of turbulence and diffusion in nutrient
transport in fixed-film biological processes
(Denmark, France, Japan, Thailand, U.S.A.).
the widespread use of fixed-film systems, especially
rotating biological contactor systems, throughout
Europe and Africa.
installation of rotating biological contactors in
primary sedimentation tanks to improve treatment
performance (U.S.A.).
the independent and concurrent development and
evaluation of single-sludge, biological, nitrification-
denitrification systems (Japan, South Africa).
the removal of nitrogen, phosphorus and other algal
growth stimulants in a two-stage, high-rate algal
treatment system (Israel).
the potential for use of rheological measurements
to control sludge conditioning processes (Canada).
pasteurization of raw sludges using submerged
combustion of digester gas (Federal Republic of
Germany).
the economical use of thermophilic aerobic digestion
over anaerobic digestion for sludge stabilization
(Federal Republic of Germany).
the resistance of k&c. ova to inactivation in
sludge treatment (South Africa).
regulation of landspreading of sludges based on
absence of E. coti, AaccvUa ova and pathogenic
viruses (South Africa).
the use of a hamster-cell transformation assay to
measure carcinogens and toxicants in reclaimed
wastewater and drinking water (South Africa).
the need to evaluate the effects of microbial
adaptation and mutation on the use of indicator
microorganisms (Japan, U.S.A.).
the role of adsorption on ultrafiltration membranes,
aluminum hydroxide floes and glass powders in re-
moval of enteroviruses (Brazil, France, U.S.A.).
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the continuing interest in use of ozone to modify
structure of nonbiodegradable compounds to bio-
degradable end products (U.S.A., South Africa).
the stimulation of bacterial regrowth in drinking
water by residual organic matter following ozonation
(Switzerland).
the need to incorporate atmospheric deposition
rates and improve upon water quality prediction
capabilities of SWMM models for urban runoff
(South Africa).
increasing importance of including internal nutrient
sources in nutrient balances used to study lake
eutrophication.
the release of phosphorus from surficial sediments
to lake water resulting from anaerobic destruction
of insoluble ferric iron compounds (U.S.A.).
the use of three coal gasification plants by the
South African Coal, Oil and Gas Corporation, SASOL,
to meet approximately 20% of the petroleum needs
of the country (South Africa).
the use of biological oxidation, carbon adsorption
and ion-exchange processes to reclaim wastewaters
at SASOL plants for industrial reuse (South Africa).
concentration of coal-gasification wastewater
effluents using cooling towers and brine disposal
to coal-ash piles (South Africa).
the expanding development and testing of fluidized
bed, expanded bed and fixed-film/suspended-film
systems for biological treatment of carbonaceous
and nitrogenous materials (United Kingdom, South
Africa).
a demonstration study on the Simon-Hartley Captor
process using porous pieces of plastic in an aera-
tion tank to increase biomass concentration and
enhance removal of carbonaceous organic matter
(United Kingdom).
the importance of anaerobic conditions to the growth
of AcumtobacteA. and successful application of bio-
logical phosphorus-removal systems.
the negative impact of low COD/TKN ratios, lack of
anaerobic conditions and presence of nitrate-nitrogen
on biological phosphorus removal systems (South Africa
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-- improved biological phosphorus removal by using
long sludge ages due to internal accumulation of
chemically-precipitated phosphorus in mixed liquor
(South Africa).
-- the reappearance of VibfUo ckoleAae. along the
Southern coast of the United States and the Natal
coast of South Africa; antibiotic-resistant cholera
is endemic throughout most of Africa (U.S.A., South
Africa).
-- the development of a small, disposable gas chroma-
tograph for use in performing field analyses
(South Africa).
-- the use of biological denitrification in Paris for
treatment of drinking water (France).
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CHAPTER I
INTRODUCTION
BACKGROUND
The International Association on Water Pollution Re-
search and Control (IAWPRC) is a non-governmental professional
organization with the goal of advancing water pollution research
worldwide to enhance the quality of the earth's water resources.
Through conferences, workshops, symposia, and publications, e.g.,
IdaXeA ReA&vich and WcuteA Science and Tzcknology, IAWPRC provides
a means for the international communication of research results
and new information relative to water quality control. The or-
ganization is governed by representatives of national committees
of member countries. Each national committee, as a condition of
membership in IAWPRC, represents the water quality research-
related activities in the respective country; currently, 29
countries are members of IAWPRC.
The United States of America National Committee (USANC)
is recognized by IAWPRC as the national organization representing
United States water quality research interests in IAWPRC. USANC
is sponsored by five major professional organizations with interests
in water quality research: (1) American Chemical Society;
(2) American Institute of Chemical Engineers; (3) American Society
of Civil Engineers; (4) Association of Environmental Engineering
Professors; and (5) Water Pollution Control Federation. Each of
these professional organizations provides a modest amount of
financial support to USANC for membership in IAWPRC and appoints
two delegates and two alternate delegates to serve on USANC.
An international conference, sponsored by IAWPRC, has
been held biennially since 1962. Prior to the Eleventh Inter-
national Conference in Cape Town, South Africa, March 29 - April 2,
1982, conferences were held in London, Tokyo, Munich, Prague, San
Francisco, Jerusalem, Paris, Sydney, Stockholm and Toronto. The
1984 Conference is scheduled for Amsterdam, The Netherlands,
September 17-20, 1984; Rio de Janiero has been nominated as the
site of the Thirteenth Conference in 1986. The conferences
represent the largest international gathering of research engineers
-------
and scientists, consulting engineers, manufacturers of process
control equipment, administrators of water quality control pro-
grams and others involved in water quality control.
The purpose of this report, prepared by USANC for the
Office of Research and Development, U.S. Environmental Protection
Agency, is not to present a verbatim record of the Conference.
Papers, and workshop and poster presentations, complete with formal
and informal floor discussion and responses from authors, have been
published as a Proceedings in a professional journal of IAWPRC
("Water Pollution Research and Control: Parts 1-4." (hlcuteA
Science and. Tzchnology, 14, 4/5, 1-406; 14, 6/7, 407-794; 14, 8,
795-1044; 14, 9/11, 1045-1614 (1982)). Rather, the purpose of
the report is to present a timely and critical analysis of formal
and informal developments at the Conference which are of potential
interest to EPA. The report represents an assessment by United
States participants in the Conference of the significant develop-
ments at the Conference. Contributions of individual authors from
various countries of the world are considered in the context of the
reception which they received from discussers and the international
audience. The analysis is not limited to formal conference develop-
ments, but includes developments from the informal exchanges be-
tween engineers and scientists from various countries which in-
evitably occur at such conferences outside of the formal sessions.
The technical program for the Cape Town Conference was
developed by the Program Committee of IAWPRC from papers submitted
from around the world in response to an invitation to submit papers
covering a wide range of subjects, e.g., the ecology of natural
waters, limnology, micropollutants, fish toxicology, marine and
estuarine pollution, runoff from agricultural and urban areas,
treatment of municipal and industrial wastewaters, and sludge
treatment. Reprints of papers selected for the program were
available to participants in advance of the Conference, and only
abbreviated summaries of the papers were presented by the authors
in Cape Town. Formal discussers were selected prior to the Con-
ference to prepare critical analyses of each paper. Additionally,
appreciable informal discussion of the papers and of the formal
discussions occurred. Appendix I contains the program for the
Conference and provides additional information on the conduct of
the sessions.
REPORT DEVELOPMENT
This report was prepared by those United States partici-
pants in the Cape Town Conference who presented papers, presented
formal discussions of research work described by others, chaired
or recorded sessions and workshops, and participated in IAWPRC
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Governing Board activities and who elected to participate in the
project. Development of the report was coordinated by a Sub-
committee of USANC consisting of USANC officers for 1980-1982
(F. G. Pohland, Chairman; R. S. Engelbrecht, Vice-Chairman;
R. A. Conway, Secretary-Treasurer) and D. G. Stephan.
Prior to the Conference, the USANC Coordinating Sub-
committee ascertained the interest of Conference participants
in contributing to the development of this report and solicited
expressions of interest in reviewing particular sessions at the
Conference (Appendix II). Assignments for coverage of all the
sessions were then made as indicated in Appendix III.
Appendix IV contains the instructions given to participants
for the development of this report.
Reports by the individual participants are included in
Chapter II. Aside from minor editing to render the reports
compatible with the general format and to eliminate items un-
related to water quality research, the reports are published
here as received from the authors. Thus, the reports represent
a critical assessment by United States water quality control
researchers and other professionals of those sessions of the
Conference which received their special attention. The individual
reports appear under the by-line of the reviewers and represent
their personal views--not necessarily the views of the Coordinating
Subcommittee or USANC.
Highlights of Chapter II, as perceived by the Coordinating
Subcommittee, are summarized in Chapter III. In addition, informa-
tion submitted by individual participants on developments at the
Conference unrelated to their sessions are summarized in Chapter III.
The Executive Summary is an abbreviated version of Chapter III.
Users of the report will find the Table of Contents
together with the Key to Reviews useful in locating in Chapter II
the discussions of particular papers, workshops or poster presen-
tations. Additionally, Appendix I should be useful in gaining
a perspective on the Conference and on the contents of Chapter II.
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CHAPTER II
CONFERENCE SESSION REPORTS
I. SESSION
A. Day: Monday, March 29, 1982
Hall: A
Time: 11:45 a.m. to 12:00 p.m.
B. Theme of Session: Monitoring Systems and Strategies,
Buoyant Jets, Taste and Odors
II. REVIEWER
A. Name: Betty H. Olson
B. Position and Affiliation: Associate Professor of Social
Ecology, Environmental Analysis
University of California
Irvine, CA (U.S.A.)
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 1: "The Effect of Submarine Wastewater Discharge
on the Bacterial Quality of Surf Water," by
D. J. Livingstone (South Africa)
Livingstone (South Africa) discussed the impact of the intro-
duction of wastewater treatment and discharge lines for sewage coming
from several areas along the Durban coast. The main thrust of the paper
was the use of a microbiological scheme for rating the occurrence of
EAckeAickia. coti 1, parasite units, Stapkiococc.ua> and salmonellae and
salinity. This numerical scheme was used to evaluate surf water quality
before and after the construction of two submarine outfalls. It was
noted that a significant improvement in the quality of the surf of the
bathing beaches occurred after the operation of the outfalls began.
Livingstone (South Africa) described the central area of
Durban before the construction project which then processed approxi-
mately 90,000 m3/d of wastewater in 1964. In the vicinity of the
harbor, wastewater was temporarily stored after screening and dis-
charged with the outgoing tide at the mouth of the harbor entering
the sea. Outside the harbor to the south, approximately 20,000 m3/d
was injected into the surf via an outfall. In addition, there were
numerous minor discharges along the sea coast.
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Factors of major concern in this study were two outfalls,
one located at the central works at the harbor of Durbin and the
other located at the southern works adjacent to the Umlaas Canal.
The pipe line at the central works was 3.2 km long and that at the
southern works was approximately 4.2 km in length. The diffuser
section was 421.8 m long for both pipes. The discharge-line diameter
at the central works was 1.22 m while at the southern works it was
13.7 m. The average discharge from the diffuser at the central
works was 77,400 m3/d and at the southern works was 72,000 m3/d.
A monitoring scheme was developed which allowed the
examination of bathing beaches prior to and after the initiation
of treatment. Further, sampling areas also included sites which
would show background levels of pollution which came from sources
other than sewage, such as rainwater runoff or streams and rivers
entering the surf zone.
Importantly, this paper considered the oceanographic and
current dynamics of the area. Although the main current is south-
wardly, topography and the subsequent movement of the Agulhas
current inshore result in a flow along the shelf in a generally
northward direction. The near-shore currents tend to flow parallel
to this course and reverse direction in association with atmospheric
pressures every one to three days.
The author demonstrated a marked improvement in water
quality after the installation of treatment and discharge lines by
applying his indicator system as follows; bathing beaches were
divided into four categories: (1) good; (2)fair; (3) poor; and (4) very
poor. These categories were assigned indicator values: 1-4 would
be classified as good, 5-8 would be classified as fair, 9-16 as poor,
and greater than 16 very poor or a "category 4" quality of seawater.
A summation of the work can be stated in the fact that
during the period of 1964 and 1965, category 1 waters accounted for
5 of the samples, category 2 accounted for 8, category 3 for 10 and
category 4 for 5 samples. Again in 1967 before discharging via the
pipe, the average for all 26 sampling stations was category 1
beaches accounted for 3, category 2 beaches accounted for 6,
category 3 beaches accounted for 12, and category 4 beaches
accounted for 7.
The sewage treatment plant and the discharge pipes at the
southern works began operation in 1968 and at the central works in
1969. Sampling done in 1970 showed a remarkable change in quality
parameters; 16 of the sampling stations were classified as category 1,
while 6 were category 2, 4 were category 3 and 2 were category 4.
The importance of a diffuser line was observed when treatment
failure occurred at the central works in 1970. Even though untreated
effluent was being discharged, the quality of the bathing beaches
remained good with 18 of the 26 beaches classified as good. It is
important to note that at several sampling stations, water quality
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did not improve with the construction of sewage lines for deep
ocean discharge,the reason being that many pathogens or indicator
organisms were being washed into the surf area through drainage
ditches, canals or river flows which enter the surf zone. This
is an important point made by the paper. Sewage treatment and
ocean discharge may be excellent at removing inputs from citywide
sources or those sources directly linked to the sewage treatment
plant, but in areas where bathing beaches are exposed to open
drainage and where these drainage areas can be impacted by various
types of fecal pollution, either from human or animal sources,
then degradation of quality will occur around those areas regard-
less of sewage treatment.
Olson (U.S.A.), the official discusser, stated that the work
clearly indicated the importance of marine outfalls in decreasing
onshore microbial pollutants as well as the impact of nonpoint
sources in the microbiological degradation of marine bathing
beaches. Her discussion focused on three areas: technical,
theoretical and practical aspects of the classification approach.
Regarding technical issues, Olson (U.S.A.) pointed out that
the sampling procedures appeared to not adequately address (1) wind
direction, (2) current reversals, and (3) wave action, which can
dramatically affect results. No reference was given as to time of
day of sampling which had been established as important in deter-
mining bathing beach quality. Further, she pointed out the impor-
tance of designating where in the water column a sample is taken,
as it can have a public health significance. She also stated that
time of year is important due to intensity of beach use. Lastly
and importantly, the need to know the quality of effluent should
be addressed as it represents the maximum load of organisms re-
leased with a potential to reach shore. Frequency of sampling
must, in addition, be addressed if statistical analyses are to
applied to the data.
Regarding theoretical issues, the epidemiological rela-
tionship between an evaluative water quality scheme and the indi-
cator or pathogen of importance is a difficult topic. Neverthe-
less, it should always be considered. The relationship of the
designated scheme and its health significance is difficult to
ascertain. Thus, the concept of dilution must be tempered by con-
centration (i.e., shellfish) depending on the source of exposure
and the exposed population.
Pathogen dose, route of entry and virulence should be
considered. Therefore, an indicator system must incorporate
organisms which are short-lived in sea water (i.e., SaZmoneMa,
Shigella, StapkZococcuA, Taenia or Aacosua) as well as those which
mimic longer-lived pathogens (i.e., I/. eholoAae or viruses).
Optimally, the indicator system should also be applicable to
shellfish.
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With respect to practical aspects, a monitoring system
must encompass both technical and theoretical considerations as
well as meet the further restriction of ease of utilization.
This is no easy accomplishment. The methods employed must be
reliable, reproducible and easily carried out.
Olson (U.S.A.) stated practical monitoring has a difficult
objective--to predict potential health threats. The best approach
may be to examine the bathing beach as well as the effluent dis-
charged to assess the maximum potential pollution which could reach
the beach. She pointed out that the approach by Livingstone (South
Africa) was admirable in its thoroughness, but required extensive
laboratory expertise and analysis which are lacking in most moni-
toring laboratories in the United States.
Lastly, she queried if a simple E. cotc index would have
resulted in the same or different classifications of the bathing
beaches studied.
Best (South Africa) asked Livingstone (South Africa) to
comment on a recent newspaper report which implied cholera had been
found in shellfish as well as along the beaches. Livingstone (South
Africa) replied that shellfish have the ability to concentrate
bacteria from water, rejecting most of the particulate matter. He
further stated that shellfish which had been properly cooked posed
no health threat. He said the source of these organisms was not the
outfalls but was from the rivers and drainage ditches which contain
large amounts of lAtbio zholdAaz.
Shuval (Israel) queried Livingstone (South Africa) on
what can be gained from a battery of tests rather than one test.
He suggested an analysis-of the data to determine whether this change
would have resulted in any other outcome in the classification of the
quality of the bathing beaches. Shuval (Israel) went on to state
that schemes used in public health determinations must be understand-
able and easily carried out. The basis of monitoring is to establish
a simple straightforward system which could use a statistical basis
for a rapid test applicable to many areas where you can take into con-
sideration daily variations over a bathing season. By using a highly
complex scheme with many of the tests having a questioned validity,
the purpose of the monitoring operation is defeated. Monitoring
should be aimed at routine, relatively inexpensive tests which predict
the state of quality. He referred to Cabelli's study which is the
only one which exists today which indicated that EntoA.oc.oacA. and
E. aott correlated with disease. Primarily, rotavirus among children
is the suspected causative agent.
Livingstone (South Africa) replied that the study was aimed
in two directions. One clearly showed when pollution was from an
outfall, E. coti or even Shigella or fecal segments containing
TaeyvLa. could be found. However, in beaches affected by nonpoint
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sources, E. coti would not predominate. Also, when a sewage out-
fall is present, salinity is decreased.
Nupen (South Africa) commented on the degree of thought
which had gone into the design of the evaluation system. She also
commented that enterovirus monitoring was being carried out at
these sites by her laboratory. Nupen (South Africa) asked what the
correlation was between her coliphage tests and the present coliform
system.
Livingstone (South Africa) replied that they were finding
a trend between the coliphage and E. coti. He also said standard
membrane filtration techniques were used to recover coliforms. His
laboratory had selected MacConkeys agar which is not used by all
countries.
Grabow (South Africa) asked if studies by Livingstone
(South Africa) had shown that there were differences in the types
of coliforms found in marine waters and how these factors might
affect his water quality parameters. The author replied that his
laboratory had examined a variety of coliforms as distinguished by
the IMViC test. In addition, they examined StapktococcU, Salmonella,
typhi, PtzudomonaA and ?Kotuu. He stated that many of the common
parasites found in stools were difficult to measure in seawater
due to rapid distortion of the characteristics.
B. Paper No. 4: "Surface Dilution of Round Negative Buoyant
Jets--A Comparison with Other Jets," by
G. Noutsopoulos and J. Demetriou (Greece)
Sewage disposal in the marine environment usually occurs
through a submarine pipe which often ends in a diffuser system.
These systems depend on an effluent density lower than that of sea
water to produce turbulence, mixing and dilution of the effluent at
the surface. Orientation of the velocity vector at the discharge
section, with respect to the gravitational field, plays a very im-
portant role in the flow pattern. Round vertically-upward dis-
charged jets (positive buoyant jets) and round horizontally-discharged
jets (horizontal buoyant jets) have been the most commonly studied.
Surface dilution factors of a negative buoyant jet design was
examined, and its effectiveness was compared with the other two
designs. A negative jet design creates two flow boundaries:
(1) internal: enclosing downward flow, and (2) external: enclosing
upward flow. The internal flow is similar to the jet type while the
external flow is similar to a plume flow pattern.
Experiments were conducted in a 1.15 m x 1.15 m x 1.40 m
tank with glass vertical faces to observe flow patterns. An iron
pipe of 2.1 cm ID was placed vertically in the tank to a designated
depth. Tap water at a constant head entered the pipe and was re- ^
leased into a sea water solution with a density of 1.01 to 1.03g/cm .
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The results indicated that the dilution distribution along the radial
jet gave a continuous increase in dilution with distance from the jet
axis. Surface dilution was larger for increasing radial distance
from the jet axis and was found to be equal to that of a positive jet.
Data presented by the authors indicated that the negative jet design
would be better in very shallow waters. Dilution with the horizontal
jet was found to be less than that of the positive jet and, therefore,
was less than the negative jet design.
Negative buoyant jet design could be useful from an
engineering standpoint when it is difficult to lay pipe along a
bottom or in very shallow waters such as are found in the Mediterranean
The same dilution as is achieved with more traditional designs can
be achieved and thus the negative jet appears to have some useful
advantages depending on circumstances.
The invited discusser stated that the approach of the
experimental work was most innovative. He also pointed out that the
amount of scatter which appeared in dilution data made it difficult
to determine if there was a good relationship between the negative
and positive jet design. Further, he stated that the authors should
have placed confidence intervals around the regression lines to more
accurately interpret the data. The discusser also indicated that the
cost involved in erecting a negative jet would outweigh its useful-
ness under most circumstances. A discusser inquired as co the
reason that the authors felt there was so much scatter obtained in
the plume region. The authors responded that this was due to the
very small values of mass concentrations obtained at the level of
measurement.
C. Paper No. 7: "The Distribution and Significance of Toxic
Metals in Sharks from the Natal Coast, South
Africa," by R. J. Watling, H. R. Watling,
R. C. Stanton, T. P. McClurg and E. M.
Engelbrecht (South Africa)
The main thrust of this paper can be divided into two areas:
use of sharks as a bioassay system for pollutants of the ocean and
the distribution of metals in three types of sharks. The Mako shark
(I-4UA04 oxynkincuA), Dusky shark (CaAchcvUnuA ob4cu>uu>) and Great
White shark (CaAchaAodon caAehcvuxu} were selected for their dif-
ferential feeding habits. The Mako shark is known to consume fast-
swimming palaegic fish while the Dusky shark consumes pilchard and
the Great White shark is known to consume dolphins and whales as
well as pilchard. The value of such an assay system is in the gener-
alization of the findings from a top carnivore in the food chain.
The shark population may be able to delineate the general pollution
status of the deep ocean as well as near-shore oceans.
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The major findings of the study are summarized in the
distribution of the metals in shark tissue. Sharks are unique in
the fact that they rapidly lay down recently consumed products in
their tissue because the kidney is inefficient in excretion. This
is another reason why sharks are likely to retain the majority of
pollutants taken in. The authors indicated this particular type of
organism would be a good pollution indicator because of the rudi-
mentary structure of the kidney. Most of the elements studied are
deposited in the liver and muscle. There are variations in the
amount of mercury and other metals which were laid down in various
tissues of the shark. Mercury was laid down in the muscle and also
the brain. The liver contained high concentrations of most metals
including cobalt. The levels of cadmium were high in the liver of
the Dusky shark. Mercury, copper, lead and zinc were able to enter
the embryo of these viviparous organisms while cadmium was excluded.
It was also found that with certain sharks, the Dusky shark for
example, there was an exponential relationship between total
length and concentration of mercury but that this exponential
relationship did not exist between metal and total mass. It was
the opinion of the authors that perhaps an asymtotic relationship
would be reached in terms of mass. Mercury, the primary metal of
study, was found to be in three forms: methyl mercury, ethyl mercury
and a third unidentified form which was believed to be a phenolic
form of mercury. The authors believe that if this latter type were
indeed an aromatic mercurial compound that it would indicate the
laying down of an unmetabolized pollutant in the tissue of the shark.
This would mean that the organism was excellent at indicating pollu-
tion of this type. The authors concluded that sharks could be an
excellent monitoring system for sea fisheries for such metals as
copper, lead, zinc and mercury. They felt that the use of the in-
dicator could be extended to certain other compounds such as poly-
aromatic hydrocarbons.
The comments of the official discusser, Massaro (U.S.A.),
centered on sources of mercury pollution. He pointed out that approxi-
mately 10,000 tons of mercury are mined and distributed each year.
Further, mercury is added to the atmosphere through the use of coal
and oil as well as the smelting of sulfide ores and in the production
of cement. However, he noted that 175,000 tons of mercury are re-
leased into the atmosphere via degassing processes in the world.
Increases in the degassing rate through farming and other earth-
moving practices may be substantial. Massaro (U.S.A.) noted the
problem with the localized inputs of mercury and the possibility
for poisoning. He cited one example in which the normal background
level for fish is considered to be 0.2 mg11 mercury (wet weight).
Fish do not exhibit toxic effects up to and including 10 mg/I
mercury (wet weight). He noted that individuals who became ill
from consuming fish in Minimata were consuming fish which contained
approximately 50 mg/£ (wet weight). He also stated that it is not
unusual to find fish in or from palaegic waters which contain 5-6 mg/I
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mercury. Given these factors, he went on to state that our under-
standing of mercury is not complete at this point. For example,
what occurs when other metals are also present in the fish? He
pointed out that the toxicity of mercury is ameliorated by selenium.
Selenium has been found in high concentrations in tuna. Does this
mean that the individual who consumes tuna with high concentrations
of both mercury and selenium is at less risk than a person consuming
a fish with high concentrations of mercury alone?
The author responded to the auestions of Massaro (U.S.A.)
at three levels. The first two of these concerned the question of
how to define an adequate standard for the intake of metals by the
population at large. He pointed to the fact that how to obtain
samples from a fishing boat is an extremely difficult question
which has not yet been properly addressed. He gave the example of
Italy which requires 10 fish to be examined from a boat containing
1,000 fish, 20 fish from a boat containing 10,000 and 25 fish from
a boat containing 100,000 fish. It is obvious that the possibility
of sampling error utilizing such techniques is great. However, the
accuracy necessary perhaps to produce a statistically meaningful
sample may be cost prohibitive. However, the point taken by Watling
(South Africa) should not be ignored but should be aggressively
addressed. It must be possible, given our scientific knowledge and
background, to develop a method of sampling which provides adequate
information as to the metal or pollutant concentration in the fish
in a cost effective manner.
The next question concerned how much of a metal should a
given community be allowed to ingest. Watling (South Africa) re-
jected the idea of a fixed number but suggested the use of a sliding
scale that would be dependent upon the type of fish to be consumed
and the type of community. By this latter statement, Watling (South
Africa) was referring to the dietary habits of the community. This
is an interesting concept which has not been explored to any great
degree by regulatory agencies. The lack of interest in this type of
approach is most likely due to the difficulty in trying to establish
baselines for different types of communities and the complication of
trying to discern the eating habits of an area. However, this does
not negate the merit of the approach and perhaps we should begin to
look at alternatives that are not based on absolute numbers.
Massaro (U.S.A.) pointed out that it was unfortunate that
the authors did not report on selenium in sharks. Watling (South
Africa) responded that the selenium analysis technique had not been
perfected in their laboratory at the time the investigation was
undertaken. He further pointed out that, in an international round
robin, their laboratory was obtaining values 20 times higher than
reported for the standard sample. He attributed this to the use of
a closed sample technique which he believed was recovering higher
amounts of selenium than are found in ordinary analytical techniques.
He stated that his laboratory would soon be able to analyze for
selenium, arsenic and antimony. The question of analyses for both
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selenium and arsenic is one of difficulty. No matter what the medium
being analyzed, it still presents analytical problems. Until it is
possible to obtain reliable measurements of selenium in various biolo-
gical tissues, the question of its use on a wide-scale basis is diffi-
cult.
Chapman (South Africa) inquired about the use of the geo-
metric mean in statistical analyses. He further asked whether the use
of the geometric mean meant that there was a high variation for the
metals encountered in the sample tissues, as was reported in the
figures for mercury.
Watling (South Africa) commented on background variations
and said that their values for their shark population studies were
near background levels. He then referred to another report which had
investigated sharks captured on the west coast of South Africa whereas
their study was done on the east coast. West coast values were an
order of magnitude lower. He hypothesized that the reason why levels
in shark tissues from the east coast may have been higher were due to
the more polluted nature of the east coast and perhaps to the sharks
having taken prey with higher levels of metal. He reiterated the
need for monitoring which would give information on the fate of
pollutants in deep ocean species at the top of the food chain.
Olson (U.S.A.) asked whether the authors were able to deter-
mine if the sharks had fed in a localized area or whether their
intake had spanned a very wide range of the ocean. She further
queried whether or not this targeted indicator organism could be
used for other organic pollutants.
Watling (South Africa) responded that it was difficult to
determine the actual feeding patterns of sharks and that tagging was
being carried out in order to increase the understanding of shark
migrations through the oceans. A larger data base was needed to
interpret the findings to particular sites. He also stated that
sharks appear to be excellent for monitoring such compounds as PCB,
DDE, DDT, Dieldrin and Camphloclor. These compounds had been found
in high concentrations in both shark liver and muscle. He said that
their laboratory had plans to expand their analyses to cover other
aromatic hydrocarbons.
In conclusion, it would appear that sharks are an interesting
organism to view in terms of monitoring. There appear to be, as with
any monitoring system, some difficulties yet to be worked out such
as the migratory patterns and exact diets of these fish as related to
potential pollution hazards. Even given these drawbacks, the use of
sharks for pollution monitoring seems at this point to be an excellent
potential indicator of the pollution status of the deep oceans.
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D. Paper No. 10: "Baseline Studies and Continuous Monitoring
for a Shallow Tropical Bay Receiving Nickel
Refinery Effluent," by J. E. Carey,
M. A. Pettit, W. S. Rooney, and T. L. Judell
(Australia)
Judell (Australia) presented the paper on predischarge base-
line studies and long-term post-discharge surveillance program under-
taken to monitor the effect of nickel refinery effluent on coastal
waters on Halifax Bay, Queensland, Australia. The plant producing
the effluent was an ammonia leaching refinery. There are only two
of these refineries in the world. In order to determine the toxicants
which should be investigated, short-term toxicity studies were con-
ducted. These tests were made utilizing two types of commercial fish,
Golden-Lined Whiting, S-UULolqo anaLU, and Northern Whiting, S. A-chama.
The tests demonstrated the amount of ammonium sulfate, free ammonia,
nickel and cobalt which could be released in the effluent without
overt toxic effects. Longer term studies involved determining water
movement in Halifax Bay. The findings from this part of the study
showed that the Great Barrier Reef, located 30-40 km from the re-
ceiving water in Halifax Bay, was not affected. The discharge was
released through an outfall 20-30 km in length equipped with a hori-
zontal diffuser. These findings also showed that flows from creeks
from the immediate vicinity had a dramatic effect on water quality.
Differences in water quality during wet and dry seasons of the year
were noted. Sediment studies were also carried out to determine if
nitrogen affected activity within sediments. Sediment samples were
analyzed for grain size, Eh-pH measurement and chemical analyses.
Seawater was also characterized for sodium, potassium, calcium, and
magnesium concentrations and a number of trace elements including
nickel, lead and cadmium. Further, pH, chlorinity, ammonia-nitrogen,
nitrate-nitrogen, total phosphate-phosphorus, turbidity, temperature,
visibility, BOD, nickel and cobalt concentrations were measured at
quarterly intervals.
Chlorophyll-a concentrations were monitored on a monthly
basis as an indicator of phytoplankton standing crop. A decrease
in chlorinity and an increase in all nutrients were evident after
the beginning of the wet season (January - March) as a result of
land runoff. Phytoplankton growth was also affected during the wet
season. Natural phytoplankton blooms of the blue-green alga,
TfUahodumcum species, were found to occur with rises in temperature
and influx of nutrients which led to fish kills. The author empha-
sized that the complexity of the marine ecosystems suggested that
many years of -en titu monitoring of biological responses to effluents
are needed before modeling for predictive purposes will be possible.
Benthic vertebrates present on the sea floor were also
used as models because they may be indicators of changes in the
environmental conditions. Results showed that in intertidal zones,
with its constantly changing microenvironments, relationships
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between substrate type and faunal communities were the most pro-
nounced. Bivalves were the most abundant group of organisms in
the intertidal habitat. In soft substrates, polychete worms
and crustaceans predominated.
Shannon-Weaver indices were computed in order to determine
diversities. The results indicated that no differences could be
discerned from inputs of effluent. No effect was noted on commer-
cial fishing in the bay.
The authors pointed out that in long-term monitoring,
consistency and continuity of operators and their supervision of
sampling sites must be considered. They emphasized that standardi-
zation of methods, both sampling and analytical, was necessary in
order to produce meaningful results.
The authors also pointed out the importance of the
stability-diversity hypothesis which has been used in recent years
as a basis for water-quality assessment. The purpose of the index
is to show that in stressed environments,less diverse communities
are found, while in stable environments, the diversity of the com-
munity or the number of species encountered increases. However, in
practice there appears to be no simple relationship between diversity
and stability. The authors pointed out that diversity may vary for
reasons other than environmental stress, such as species interactions,
climatic variability and greater spatial heterogeneity of the habitat.
Clark (United Kingdom) stressed two main points in his
formal discussion. The first of these was the general importance
and difficulty in carrying out a comprehensive monitoring program.
No matter how good the study, problems will still exist because there
are no methods yet developed which measure small changes in the com-
munity. Measurements of diversity are not always reliable in describing
why changes are occurring, including the indices used by the authors
and exemplified by the disagreement between the Shannon-Weaver index
and the Gray and Mirza log-normal diversity index. He further stated
that the time of year that sampling is carried out can be extremely
important. One would wish to pick a time of year when natural per-
turbations were at a minimum. The two examples of high mortality,
independent of environmental inputs (after spawning and the entry
of new recruits into a community which usually die), cause erratic
changes in the diversity index for a short period of time. In
England, the optimum time of the year for such a diversity study is
during the autumn when natural perturbations and fluctuations are
at a minimum.
Clark (United Kingdom) emphasized the need for more than
mechanical methods in order to understand changes in the ecosystem.
He mentioned the extreme difficulty in this pursuit given our current
technology in ecosystem study, even in areas where the species are
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well defined and where the habits of these species are known and the
ecosystem function delineated. In areas where little is known about
biology, one must rely on measurements of change such as diversity
indices.
The second point of the discussion focused on the length
of a monitoring program. Clark (United Kingdom) indicated that
large impacts from an effluent are obvious and changes can be
determined in a very short period of time. However, if changes
are difficult to detect, then it becomes virtually impossible to
evaluate or to measure toxic effects. One can conclude from this
either that no toxic effects are occurring in the environment or
that the methods used are not sensitive enough to delineate a toxic
occurrence. He concluded by stating that until the structure,
energetics, and functions of an ecosystem under study are understood,
it will be nearly impossible to monitor subtle changes due to
effluent input.
The reply by Judell (Australia) centered on the length of
the monitoring period. He stated that the prolonged monitoring of
an area produced management benefits as well as scientific benefits
and, if routine monitoring could be carried out economically, then
all would benefit. The information gathered by the management could
be disseminated to the government and aid the company and the govern-
ment arriving at judicious standards and monitoring programs.
Rosemond (Australia) commented at some length on the
initiation of the study. At the time the study was initiated, he
was director of the Water Quality Council which was directed by the
Queensland government to establish the monitoring program with the
consultants. His comments centered on several points. Although
an industrial process has been used in another part of the world, he
emphasized the importance of understanding how that process affects
a specific environment. Further, findings from one environment are
not always translatable to another. Secondly, he emphasized the
importance of decisions having to be made in a political atmosphere.
During these times it was his opinion that decisions must be made
quickly and based on a minimum amount of information. It appears
from the types of decisions made in this arena that it is possible
to achieve results which are satisfactory to all and which protect
the environment. This third point was that monitoring should be
based on trends rather than on setting a single number standard. He
concluded that although there was no difficulty nor noticeable
problems being experienced with discharges of this effluent into
Halifax Bay, fish kills occurred when effluents spilled into nearby
wetlands. Pointing out that judicious and vigilant observations
are always site specific, he believed that long-term monitoring
is needed to distinguish between slight perturbations in the environ-
ment caused by an effluent and those which occur naturally.
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Froneman (South Africa) questioned the effects of free
ammonia. He again reiterated the facts pointed out in the paper
that free ammonia is toxic and that toxicity is pH dependent. He
further stated that his data showed fish kills could be caused by
small increases in temperature at a pH of 8 due to ammonia. Judell
(Australia) replied that these factors had been taken into considera-
tion but in Aitu, no differences in toxicity could be noted even
during the warmer months. He also stated that the complexity of the
In 4
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Four main summary points can be reiterated. (1) Changes
in the environment are difficult to measure; new methods are
needed; (2) Better understandings of ecosystems are necessary
to elucidate perturbation problems of natural or man-made sources
when inputs do not have a catastrophic effect; (3) Monitoring
programs can be beneficial to industry and government as well
as to the public by contributing knowledge which has generalized
benefits; and (4) Better policy decisions are derived from the
interaction of these three sectors if decision making begins early
in the process.
E. Paper No. 13: "Influence of Discharges from Storage
Reservoirs on Tastes and Odours Appearing
in the Seine and Marne Rivers," by M. Rizet
and J. Mouchet (France)
Taste and odor problems in the Seine and Marne Rivers
which serve as a major drinking water source for the city of Paris
had occurred intermittently for several years. These problems be-
came acute during a drought in 1976. An interagency agreement
among all the authorities in the basin was entered into in order
to remedy this problem. The sources of noxious compounds were found
to be produced by different nuisance organisms in the two rivers.
Therefore, a study was conducted to compare the physico-chemical
and biological characteristics of the two river system.
Sampling locations were designed to sample water in each
system above the reservoir, in the reservoir, at the discharge
point from the reservoir and downstream near the city. The study
included the identification of microorganisms which could give
rise to uncertain tastes (algae and actinomycetes) as well as identi-
fication of other organisms which might contribute to taste and odor
problems. The presence of geosmine and methylisoborneol and other
biological and physico-chemical parameters of the water systems were
determined.
During the year from July to November, the Seine Dam dis-
charges 88-90% of its stored water. During the floods in December
through February, some water is also discharged. In the Seine
upstream from the dam, the taste thresholds did fluctuate depending
on the density of suspended solids. In the reservoir, the intensity
of the taste is at its maximum in the summer period with the pro-
liferation of algae. However, it was not possible to correlate
this with geosmine or 2-methylisoborneol.
The level of suspended solids is systematically higher
downstream as compared to upstream of the weir. Sediment deposi-
tion into the stream is dependent on the discharge point in the
reservoir. Some of the sediment input is attenuated in the canal
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leaving the reservoir. The discharge of silt can also add algae
such as O&cAJUiatofUa agaAdkU. This bluegreen alga cannot be
isolated downstream when the dam is not releasing water.
kdtLnomyc.eA.zi> do not appear clearly, except in the suspended
solids during flooding.
The Marne Reservoir which is more recent in construction
provides storage of more than 350 x 10^ m3 of water. The manage-
ment of this reservoir is different in that water is discharged
from July through December. Beyond this period discharges are
negligible compared with the flow of the river. The reservoir
reduced turbidity, except near the end of the discharge season
whenthewater level in the reservoir is quite low. Four peaks in
geosmine were measured in the upstream part of the Marne. They
had no apparent relationship either with the suspended solids or
with the Ac£cnomyteXu. ActcnomycoAu and suspended solids during
the flooding periods were closely associated. But no relationship
between these organisms and the actual taste of the water could be
demonstrated. However, in the reservoir the growth of 06CAJULa£o>u.a.
was noticed in October which did coincide with a high concentration
of methylisoborneol. This compound was not found downstream from
the weir.
Comparing the two rivers at the level of the reservoirs,
OicjlZatofUjci reproduce in the Seine whereas in the Marne River
they disappear. The algae do seem to contribute to taste. First,
the reservoir is shallow which encourages penetration of light and
stimulates growth. Silt or mud transported from the reservoir
accumulates on the bottom of the stream or river and algae brought
from the reservoir either die, as in the Marne, or flourish, as in
the Seine. Rizet (France) concluded the problem of the river
water quality from the point of view of preparing drinking water
had not always taken into account downstream pollution sources
from local sewage discharges and barrages (dams) on the river.
Quality downstream from the reservoirs was also a decisive factor
in the development of undesirable tastes as well as conditions
which promoted the growth of these nuisances.
Gehr (Canada), the official discusser, stated that the
authors attempted to explain the reasons for the taste and odors
occurring in the Seine and Marne Rivers as a result of a drought
and a subsequent flood which occurred about five years ago. They
have obviously gone to considerable trouble to measure the water
quality in terms of a number of chemical and biologic factors and
have tried to relate the occurrence of these taste parameters to
the influence of the reservoirs which separate the upstream and the
downstream portions of the two rivers which supply water to the
city of Paris. Gehr (Canada) asked about the methods used to
quantify the tastes. Such a controversial parameter as taste
should have a reference so that comparison with other work can be
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made. The authors make frequent reference to summer and winter and
other seasonal terms which are rather vague, especially to those in
the southern hemisphere.
Gehr (Canada) stated that, although the effects were clearly
a result of some organic pollution, the authors present no data on
BOD, COD, TOC and other organic parameters. Temperature data would
be an important factor to be included in such a report. Gehr
(Canada) emphasized that they should have indicated when the reser-
voir was reopened after its closing on November 10, 1976, because
of its relevance to their conclusions. Gehr (Canada) then made
comments with regard to the agreement between the data presented
and the text. He pointed out that the authors found an association
between algae and blue-green algae occurrence and taste units up-
stream and downstream of the dam. He further stated that the authors
were incorrect in their statement that suspended solids were always
higher at Villacerf than upstream of the dam.
Gehr (Canada) only discussed the analysis of taste problems
for the Seine River. He concluded that although changes had occurred
in the physico-chemical and biological parameters of the water during
its storage in the reservoir, these changes could not be related to
changes in taste of the water. This was recognized by the inability
to correlate geosmine and methylisoborneol with the occurrence of
algae. Importantly, if only blue-green algae are the cause of the
taste problems, then correlations should only be found for the
geosmine, but if Actinomyces and blue-green algae were responsible,
then both compounds would be present. The discusser concluded by
stating that more concrete data were needed to definitely show that
the reservoir was the source of organisms responsible for the taste
problems.
Rizet (France) replied that the method used to quantify tastes
were made by individual tasters and threshold levels established from
these experiments. She also stated that COD and TOC were determined
although the results were not presented. Rizet (France) commented
that it was difficult to relate Actinomyces to taste problems because
certain species produce compounds influencing taste while others do
not. Therefore, no simple quantification of this group of organisms
can be used to correlate with taste levels. In regard to the text
not corresponding with the information presented in certain figures,
Rizet (France) acknowledged errors in certain figures.
Rogers (South Africa) queried the authors as to whether
depth stratification in the reservoirs was a factor contributing to
taste problems and what treatment could be used to alleviate taste
problems. Rizet (France) replied that depth stratification was
not the main problem especially in the Seine Reservoir which has a
high degree of insiltation in certain locations. As to the removal
of tastes, activated carbon and ozonation have proven useful, but
these processes are costly.
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IV. CRITIQUE OF SESSION
Paper No. 1 clearly pointed out differences in philosophy
on how to develop a monitoring scheme to predict quality of bathing
beaches. Although Livingstone's (South Africa) presentation showed
that quality was improved with use of treatment and an ocean outfall,
the discussion focused on the rationale of the monitoring scheme.
It was clear that the audience held two main points of view: the
system must be practical and relate to health or the system must be
able to demonstrate a change in quality, regardless of its relation
to health considerations. Both have validity, the former in that
health protection is the major aim and the latter in that a positive
or negative outcome on microbial quality can be demonstrated.
The concept of how to develop a monitoring scheme would
create debate no matter what the composition of the audience or
the quality of the methods. As yet, little common ground exists
for a consensus among researchers in different countries.
An interesting and novel concept concerning the development
of a pollution monitoring system for the deep oceans was presented
in Paper No. 7. It is difficult to ascertain the full potential of
the system at this stage, because it is in the early phases of
development. Therefore, several problems remain to be solved. The
migration and feeding patterns of the sharks under study must be
fully delineated if the source of the pollutant is to be determined.
The real promise of the method is the inefficiency of the shark
kidney which allows the rapid deposition of the pollutant into the
tissue. This appears to provide an excellent mechanism to trace the
migration of pollutants in the food chain. If pollutants are laid
down in an unaltered state, and if migration patterns as well as
feeding patterns are established, it may be possible to track the
movement of the pollutant through the food chain. Further, the
movement of the pollutant as it travels within a specific segment
of the food chain could also be delineated.
Paper No. 10 was excellent in demonstrating the benefits
of a wel 1-designed, before-and-after monitoring investigation. It
could be seen from the discussion that the information being obtained
extended byeond the context of the study by pointing out significant
difficulties with designing and carrying out monitoring investiga-
tions aimed at the impact of a particular pollutant on an aquatic
environment. The discussers raised valid and important points on
the utility of species diversity indices as a measure, when they
can be useful, when they are inappropriate and under what conditions
they can soley be relied upon. What all the discussers and author
agreed upon in principle was the need for more information on the
ecology of aquatic habitats. It is difficult to determine impacts
to recommend satisfactory regulations to protect that environment.
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The research presented in Paper No. 13 represented a
cooperative venture among several scientific groups. The informa-
tion contained in the article, therefore, excluded certain data
critical to the overall conclusions drawn. A more complete under-
standing of the study could be obtained from the final report sub-
mitted to the basin interagency group. Yet, with any study of
this type, two factors should be kept in mind. First, various
nations have different emphases in approach, and second, this
directional focus is likely to influence the nature of the data
obtained and the uses to which those data can be applied.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
With regard to the significance of Paper No. 1, most
recent work relating health significance to pathogens in marine
bathing waters has occurred in the United States. The work done
by Cabelli and associates demonstrated an association between
E. coti and illness among children. More recent studies by Fattal
in Israel showed that both E. c.oLL and enterococci correlated with
virus occurrence in marine bathing waters associated with raw
sewage inputs.
In the United States, raw sewage discharges are infrequent
compared to such discharges in many other countries in the world.
However, cholera is again becoming a disease of note in the United
States, not because of the large numbers of the population affected,
but more so because of the relationship to consumption of shellfish.
The occurrence of pathogens, especially viral agents (i.e., hepatitis
A), in waste discharged near shellfish growing grounds must be viewed
as a critical issue in the United States. Adequacy of disinfection
in light of particulate association by pathogens, clumped configurations
and injury of the organisms has not been resolved to any satisfactory
extent.
Illness from exposure to bathing waters appears more com-
plex but the Cabelli work indicated a viral agent may be responsi-
ble for disease in children, the main affected population. Unfor-
tunately, at the time of the Cabelli studies viral techniques had
not progressed to present-day sophistication and therefore, direct
proof of viral-caused illness was not possible at the time.
At this stage, it is difficult to determine the relative
usefulness of the technique presented by Watling et al. (South
Africa) in Paper No. 7 to the United States. The concept of moni-
toring the oceans with a biological organism is interesting. The
return from investing in such research would have to be viewed at
this time as risky. However, if national needs are such that it is
important to track the fate of a particular pollutant in the oceans
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from its origin to its final site of deposition, then this may be
an excellent tool to pursue vigorously. Certainly, it appears to
have applicability far beyond that of metals. Sharks could also
be used to monitor the presence of a number of highly sensitive
organic pollutants such as PCBs, DDT, DDE, and aromatic hydrocarbons.
Any program which utilizes before-and-after monitoring
when introducing a pollutant into an environment is to be commended
(Paper No. 10). As pointed out by the authors and the discussants,
it resulted in better policy decisions and improved relationships
among industry, the public and government. The regulations arrived
at were satisfactory to all, because all had participated to some
degree in the process developing those regulations. Attitudes of
countries vary greatly on whether to adopt such extensive monitoring
strategies. But, as was pointed out in the discussion, results from
studies should not be extrapolated too widely. This appears particu-
larly true in the case of an environmental pollutant. Each environ-
mental location has its own sensitivities. One message from several
nations which was clearly evident from discussions throughout the
conference is the need to support basic ecological studies through
such programs as the National Science Foundation. Without these
baseline studies or the development of such tests as diversity indices,
there would be little hope of measuring effects of pollutants short
of those producing lethal outcomes. Needs are clearly directed
toward the development or the application of testing methods which
distinguish the subtle effects a pollutant may have on an environment.
The United States would greatly benefit from the information derived
from such studies as would all the countries in the developed world
and even more those developing nations which would like to avoid
costly environmental mistakes.
Taste and odor problems,as presented in Paper No. 13, con-
tinue to be a major concern of water agencies throughout the world.
In the United States, the approach has been to assess the presence
of the two main taste-producing compounds: geosmine and methyliso-
borneol. Even with our level of sophistication in the measurement
of these problem compounds, our ability to apply satisfactory cor-
rective measures lag well behind. There is a continuing need for
research to study factors which influence the growth of organisms
capable of producting taste problems. Once these parameters are
understood, it will be more likely that an effective management
strategy will be attainable. This investigation (Paper No. 13)
has taken steps in the right direction. However, without reviewing
the full report, it is impossible to say that this study led us any
closer to information on how to remove the causative agents of
taste problems from our reservoirs. Removal at this point in the
time appears more feasible than treatment of affected water due to
cost factors.
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I. SESSION
A. Day: Tuesday, March 30, 1982
Hall: A
Time: 8:30 a.m. to 12:05 p.m.
B. Theme of Session: Water Quality Management
II. REVIEWER
A. Name: Edward J. Massaro
B. Position and Affiliation: Director, Center of Air
Environment Studies and
Professor of Toxicology
The Pennsylvania State
University
226 Fenske Laboratory
University Park, PA 16802
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 16: "New Methods for Analyzing Water Pollutants,"
by L. H. Keith, R. C. Hall, R. C. Hanisch,
R. G. Landolt, and J. E. Henderson, (U.S.A.)
This paper discussed: (i) a new gas chromatograph (GC)
detector; (ii) a method of multi-dimensional gas chromatographic
analysis, and (iii) a computer-controlled GC used for the analysis.
The new detector is a thermally-modulated electron capture
detector. It consists of two electron-capture detectors in series
with a catalytic pyrolysis unit. A compound passes through the
first detector into the pyrolysis unit where catalytic decomposition
occurs. Then, one of three things can happen: the emerging peak
either can be the same size as it was in the first detector (in
which there was no decomposition) or it can be smaller or larger
than it was in the first detector. This type of information can be
used like a retention time or a melting point. Thus, under a given
set of conditions, the physical property (i.e., the ratio of the
two peaks) is a constant. This can increase the level of identifi-
cation because a retention time as well as a ratio of the peak areas
is obtained. By choosing the appropriate conditions, the peaks
emerging from the pyrolysis unit can be made either larger or smaller
than the peaks detected by the first detector and analytical selec-
tivity can be achieved without going through the process of frac-
tionating interfering compounds or classes of compounds from one
another. This, in effect, is accomplished by the detector.
Examples of the advantages of the method were discussed
such as: (i) the analysis of pesticides in the presence of PCBs in
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the absence of column chromatographic separation and (ii) the analysis
of dihaloacetylnitriles in the presence of trihalomethanes. The
dihaloacetylnitriles are a new class of compounds that are produced
by chlorination of drinking water. They occur in many water supplies
simultaneously with trihalomethanes. The dihalo compounds cannot be
detected by the standard methods used for the analysis of trihalo-
methanes because they are destroyed.
Two-dimensional gas chromatography is a simple concept:
the sample is chromatographed on one column and the compounds
(peaks) emerging pass through a valve into an electron capture
detector. From there, they pass into a second valve from which
they can be either vented or trapped. After the first column run
is completed, the trapped compounds are thermally desorbed on the
head of a second column, the properties of which are different
from those of the first column, and a second set of retention times
are obtained. Using the two retention times, the confidence level
of identification is increased significantly. This technique is
called post-detector peak recycling or PDPR two-dimensional gas
chromatography.
The utility of this technique was illustrated in a study
in which haloacetylnitriles and trihalomethanes of drinking water
were analyzed using samples spiked with standards. Small peaks
that were not detectable on the first column because they eluted
with the standards were detected on the second column. It is to
be expected that the concentrations (i.e., integrated peak area)
from both columns would be the same and, indeed, they were very close.
However, there were a few exceptions. With dibromochloromethane,
the relative concentration was 50 ppb on the first column but only
41 ppb on the second column. The reason for this is that there was
an impurity under the peak in the first column. On the second
column, the impurity was separated out. Thus, the true concentra-
tion probably was 41 ppb instead of 50 ppb.
It is, of course, not essential to have a computer-controlled
gas chromatography to do two-dimensional gas chromatography. However,
it is helpful because of the rapid switching needed to collect the
peaks of a complex mixture. The design of the chromatography described
is somewhat different from that which others have used. The major
difference is that a hot-air convection oven is not used. Instead, a
hollow aluminum mandrel is used which can be heated or cooled very
rapidly. Packed columns are wrapped around the outside of this man-
drel. A capillary column can be placed inside of the mandrel. This
type of system lends itself rapidly to mobile vans.
Van Rensburg (South Africa) congratulated Keith (U.S.A.)
on the original thinking which went into the design of the instru-
ment. The discusser asked to what extent that mention was made
that the instrument had capillary column capabilities but, in
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the examples discussed, only conventional columns with approxi-
mately 1000 effective plates had been used. He asked for clari-
fication of the advantages that the instrumentation described
would have over modern, high-quality fused-silica columns which
may have approximately 60,000 effective plates and the parallel
dual detection system presented. Van Rensburg (South Africa)
felt that in a dual detection system like the one described,
chances were very good that a certain amount of resolution would
be lost during the passage of the sample through the first de-
tector, the oven and then the second detector. He suggested com-
parison of the system described with one manufactured by another
company which uses capillary columns. Van Rensburg (South
Africa) closed with a comment on the technique used to extract
the nitriles. He mentioned that they were having a problem with
pentane as a solvent when automated water sampling techniques were
used. The problem was that pentane tended to form air pockets in
the syringe needle.
Keith (U.S.A.) replied that their instrument could be
used both for research and routine applications. They have used
it in the research mode; however, it can be set up for routine
analyses. In fact, using an auto injector, it should be possible
to routinely analyze many samples. The software program should
not be difficult to write, the instrument is not difficult to
operate and can be operated by a trained technician. The cost of
the instrument is approximately $60,000 ($20,000 for the computer
and $20,000 for each of two gas chromatographs) which is comparable
to other instruments on the market containing a comparable data
system and two gas chromatographs.
The instrument has not yet been used with capillary
columns. With respect to loss of resolution with the thermally-
modulated electron capture detector; they have seen only a slight
loss of resolution in the second detector following passage
through the catalytic decomposition unit. This may be due to the
fact that the detector is a prototype detector and has not optimized
with respect to dead volume which would prevent loss of resolution.
Keith (U.S.A.) mentioned that a parallel system of de-
tectors could be used with their instrument. However, sensitivity
would be cut in half because only one half of the sample would be
sent to each detector. If loss of resolution is not significant,
it is preferable to use the detectors in series because of the
higher sensitivity obtained. Keith (U.S.A.) indicated that they
have not had any problems with pentane extractions. However, other
solvents are available and in use.
Saunders (South Africa) requested information on the size
range of the molecules that Keith (U.S.A.) has been able to analyze
with his instrument. Keith (U..S.A.) replied that they have
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concentrated on smaller molecules and have not analyzed large
molecules.
Van Rensburg (South Africa) commented that the important
thing is use of efficient columns such as capillary columns with
about 60,000 effective plates. With such columns peaks would be
sharp and a parallel system would be highly efficient. He added
also that the electron capture detection system has its limitations
as to the type of compounds to which it is sensitive and asked
whether other types of detection systems could be used with the
instrument described.
Keith (U.S.A.) replied that the point made about the
capillary columns was a good one. With respect to other detectors,
if you had two columns in parallel, you could use other types of
detectors. In fact, at a chlorination conference held in October
(1981) in the United States, such a system was discussed in which
a flame ionization detector and a flame photometric detector were
utilized to analyze for volatile components in drinking water. He
mentioned also that some people have problems with injection into
a capillary column and that he has had problems in training techni-
cians to use capillary columns. Once this is overcome, then
capillary column chromatography always is superior to packed column
chromatography.
In conclusion, Keith (U.S.A.) commented that there were
many things that have not yet been done with their analytical system.
For example, combining the new detector with two-dimensional gas
chromatography would allow identification of compounds by peak
ratios and two retention times; greatly increasing the confidence
level of the identification. Interfacing two-dimensional gas
chromatography and mass spectrometry would allow for the identifi-
cation of unknowns,which cannot be done by single-dimensional
GC-mass spectrometry. For example, there are times when a compound
that has been identified by gas chromatography using a Hall detector
or an electron capture detector cannot be identified by mass spec-
trometry because the peak cannot be found. It may be buried, for
example, under larger peaks. This, in fact, is a common situation
in environmental analyses—not being able to identify small com-
pounds which may be the toxic compounds of interest because they
are buried under other compounds. Using two-dimensional gas
chromatography-mass spectrometry (GC-6C-MS), the peak (or peaks) of
interest could be trapped after chromatography on the first column
and rechromatographed on the second column to move the compound of
interest out from under the interfering compound(s). Another situation
which often prevails is that in which a sufficient amount of the com-
pound of interest cannot be placed into the MS ionization source
because of the presence of large amount of extraneous compounds.
This happens particularly with capillary columns. Only so much can
be injected into a capillary column. Using two-dimensional gas
chromatography, multiple injections could be made and the compound
or compounds of interest could be trapped while the extraneous
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compounds are vented. When a sufficient concentration of the
compound(s) of interest was built up, it (they) would be thermally
desorbed onto the second column and rechromatographed and enough
material would be available to obtain a good mass spectrum.
B. Paper No. 18: "Simultaneous .01 &
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be noted that temperature is very important in membrane diffusion
and all studies were made at a constant water temperature. For
calibration purposes, dissolved oxygen was calibrated by Winkler
titration and the van Slyke method and nitrogen by the van Slyke
method, the only technique available for measuring dissolved
nitrogen.
A number of measurements of dissolved Oo and N2 in
activated sludge process streams were made with tne membrane.
There was no doubt about the linearity of the response both for
O2 and Np. Also, there appeared to be no appreciable inter-
ference between the two gases. Another important feature was
the stability of the probe in the heavy suspensions of activated
sludge. One membrane was used throughout two months of work on
the sludge streams and linearity of response was maintained.
In conclusion, the membrane/gas chromatographic tech-
nique described offers a promising method for dissolved nitrogen
measurements. This system appears accurate to within a standard
deviation of 0.5% both for nitrogen and oxygen.
Van Rossum (South Africa) commented that once you
have a suitable membrane technique, you can start considering
alternative detection systems such as the mass spectrometer. Small
quadrapole-type mass spectrometers (small enough to be carried
about in a suitcase) with a mass range of up to 80 are now available
and would allow detection of any of a wide variety of substances.
Van Rossum asked Bilstad to comment on the potential problem of
membrane fouling.
Bilstad (Norway) replied that an alternative to the GC for
measuring dissolved gases in the field is the saturometer: an in-
strument that measures the total dissolved gas content of water and
can be used at great depths. Bilstad (Norway) indicated they
have been satisfied with the gas chromatograph and the next step
for them would be to use other columns in the gas chromatograph
for the quantification of other dissolved gases in addition to
nitrogen/oxygen. For example, it should be possible to measure
NH3, H2S, and CH4. He stated also that membrane fouling has not
been a problem in their studies.
Roberts (South Africa) commented that those who have
worked with nitrogen mass balances in nitrification/denitrification
activated sludge plants have been calculating mass balances with no
regard for dissolved N2 and have been happy with the balances obtained.
He asked Bilstad (Norway) to comment on the kind of variations found
in dissolved nitrogen levels in different parts of reactors in
activated sludge plants.
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Bilstad (Norway) replied that when ammonia is oxidized
and then denitrified to N2, you would expect to get dissolved
nitrogen in the last stage of the process. He noted that people
have had problems with nitrogen balances in plants that nitrify
(and therefore, also denitrify) in the settling tanks. He stated
that although you may obtain accurate data on organic nitrogen,
ammonia, and nitrate concentrations, without information on dis-
solved N2 levels (if they exist), no balance is attainable. The
plant in which Bilstad (Norway) measured dissolved nitrogen was an
activated sludge plant without denitrification and little nitri-
fication. The N2 saturation data he obtained was of the order of
118%, i.e., supersaturated.
Gold (South Africa) asked: (i) why a period of two
minutes of exposure of the diffusion cell to the test sample prior
to measurement was selected and (ii) what was the effect either of
shorter or longer periods of exposure?
Bilstad (Norway) replied two minutes was the minimum time
required to obtain sufficient gas diffusion across the membrane for
analysis, and was required to circumvent the problems of the over-
lapping of GC peaks.
Masschelein (Belgium) asked Bilstad (Norway) to comment
on the effect of temperatures, pressures and time on gas dif-
fusion across the membrane.
Bilstad (Norway) replied that temperature is important and
was kept constant during the diffusion process. Temperature was
measured at the time of sampling and the sample was cooled and main-
tained at down to 0°C but not frozen. The analyses were always
performed at a constant temperature maintained by an ice jacket.
He added that the helium inside the stainless steel tubing and,
therefore, also in the membrane loop is at a constant pressure
because helium does not flow through the loop during the diffusion
period since it is cut off for the two-minute period. During
this time, helium diffuses through the membrane into the water
(because there is no partial pressure of helium in the water) and
dissolved gases in the water that do not exist inside a tubing
dissolve into the tubing and would continue to do so until equili-
brium was reached. But two minutes is insufficient to attain
equilibrium. After two minutes the helium flow is restored to
flush the gas plug into the GC. The flushing period was four
seconds and was a function of the helium purge gas flow rate
(20 m£/min) which can be controlled and the length of the stain-
less steel tubing (50 cm on each side).
Jones (Canada) commented that he was puzzled about
the importance of measuring dissolved nitrogen and the
mechanism at work in the plant which was neither nitrify-
ing nor denitrifying but yet had nitrogen content of 118%
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of saturation. He added that, in terms of nitrogen balance, once
nitrogen has been converted into gaseous nitrogen, it is probably
not significant whether it exists as a gas or as a supersaturated
solution. Jones (Canada) also commented that, although the method of
oxygen measurement is interesting and elegant, because of the
two minute or more delay, it seems that one would have to be dealing
with a system which is in complete equilibrium. If it is not
possible to deal with a system which is transient in any way,
the method has a very limited application in research where it is
necessary to continuously or instantaneously measure the rate of
change in oxygen concentration.
Bilstad (Norway) replied that the 118% saturation measured
in the secondary settling tanks in the absence of nitrification or
denitrification was due to the hydrostatic pressure in the aeration
tank. Saturation values depend on the depth of air introduction.
For example, at 5 m there are one and a half atmospheres of pressure
and the driving force is increased accordingly ((9 mg/I) x 1.5).
Therefore, it is not at all inconceivable to find 118% saturation of
nitrogen in the settling tank. What is more difficult to explain is
why it takes so long for nitrogen to approach equilibrium after it
has become supersaturated. This is a big problem for aquatic life.
Fish in water saturated at 118% of saturation with dissolved
nitrogen can quickly develop a gas embolus and die. Thus, the
states of Washington and Oregon have set limits at 105 and 110%,
respectively, for dissolved nitrogen in rivers and effluents to
protect salmon and other fish. However, 110% is the maximum value
for salmon and trout. Bilstad (Norway) commented his technique
was primarily for dissolved N2 not O2 and that excellent rapid
techniques were available for measuring dissolved oxygen.
C. Paper No. 20: "Nutrients Removal and Recovery in a Two-
Stage High-Rate Algal Wastewater Treatment
System," G. Shelef, U. Azov, R. Moraine (Israel)
Shelef (Israel) discussed nutrient removal from waste-
water by biomass accumulation. Removal of nutrients from waste-
water effluents is necessary to control eutrophication in receiving
bodies of water. However, less than 40% removal of nitrogen and
phosphorus from strong municipal wastewater can be achieved via
biomass incorporation in one-stage, high-rate algal ponds. Thus,
the limiting factor for algal production in practical ponds is not
the algal growth potential of municipal wastewaters in terms of
nutrient availability but rather solar incident irradiance and
temperature. Additional removal of nitrogen (up to 74%) from
one-stage ponds can be achieved through atmospheric evolution of
ammonia while 95% removal of phosphorus can be achieved by algal
flocculation with alum. However,a multi-stage algal system is
required to attain high-level removal of nitrogen and phosphorous
via biomass incorporation. Use of a second-stage pond (following
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"coarse" separation by flotation of the algal biomass) yields an
effluent (following "refined" separation of the algal biomass to
remove the algae and suspended matter) containing less than 4 mg/•£
of nitrogen and less than 0.5 mg/£ of phosphorus. Sand filtration
is used to further polish the final effluent in order to use it for
unrestricted irrigation.
Use of micro algae for nutrient extraction purposes is
very efficient not only because they contribute almost twice
their production in terms of oxygen added to the water but also
because they contain 40-70% protein and protein is one of the
commodities the world needs very badly. Thus, the algal biomass
may be harvested from both stages and processed to yield a highly
proteinaceous animal feed or protein for human consumption.
Shelef et al. (Israel) have greatly increased knowledge
of intensive algae growth and harvesting. They have characterized
bacterial and algal productivity and have shown that algal pro-
ductivity undergoes expected seasonal variations while bacterial
productivity is essentially independent of the season indicating
independence with regard to irradiation and temperature. In
addition, the nutrient material balance data and experimental
results presented by the authors are most useful tools for nutrient
recovery calculations and for the planning of high rate algae ponds.
As the effect of temperature on biological processes in
wastewater treatment plants and in receiving waters is still con-
troversial, Albrecht (Federal Republic of Germany) asked Shelef
(Israel) if he would reveal the range of temperatures in which his
productivity studies were carried out and whether the seasonal
variation in algal productivity is primarily due to irradiation
conditions or temperature variations. Albrecht (Federal Republic
of Germany) commented that the effect of temperature on algae
growth is sometimes overestimated, as there is a very close relation-
ship between solar irradiation and temperature. In addition, small-
scale studies indicate that algal growth rates are similar within
the temperature range 5-25°C, if irradiation is kept constant.
Albrecht (Federal Republic of Germany) noted that the authors con-
ducted first-stage tests in a technical-scale pilot pond with con-
tinuous feeding while the second-stage tests were made in mini-ponds
as batch tests and with semicontinuous feeding. He asked Shelef (Israel)
if there are recent results which have been obtained from two-stage
algal pond systems (in which both stages are of the same scale) with
continuous feeding of both stages? If so, do these results differ
significantly from those reported in the paper? He also asked what
concentration of the aluminum chloride flocculant is used to har-
vest the algae and if any problmes are to be expected concerning
salt enrichment in the final effluent? This latter question might
be important with regard to water recycling, irrigation, and in
arid countries with respect to high rates of evaporation and small
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receiving waters. In addition, he asked if other methods of algal
harvesting have been studied such as micro-straining? Albrecht
(Federal Republic of Germany) noted that it has been documented by
several investigations that algae incorporate not only nutrients
but also considerable quantities of heavy metals. And, recent
studies have shown that even pure domestic waters may contain com-
paratively high concentrations of heavy metals resulting from
corrosion of the conduit system. High concentrations of heavy metals
could lead to undesired heavy metal loads in the harvested material.
Albrecht (Federal Republic of Germany) asked if this might not
restrict the use of harvested pond biomass as animal feed? He
noted that the authors had stated that the value of harvested bio-
mass is between $200 and $300 (United States) per ton and asked if
these figures included all treatment costs (e.g., dewatering, drying
and pasteurization). He also noted that the authors stated that
their algal pond method was applicable only under warm climatic
conditions where there is ample sunshine. However, he reasoned
that this system might also be considered in northern countries for
wastewater treatment facilities used only during the summer season
such as camping areas. For this purpose, it would be of interest
to know what the expected duration of the starting period of the
algal pond system is and what the process stability is in terms of
long-term variation of effluent BOD, COD, and other parameters.
Finally, Albrecht (Federal Republic of Germany) asked for information
on total area required per capita for the two-stage pond system.
Shelef (Israel) replied that bacterial productivity did
not vary with temperature because the residence time for algae to
grow is much longer than that for bacteria. Temperature, then,
would not affect the rate of bacterial growth because they would
have enough time to slowly incorporate and oxidize all the organic
matter at these temperatures.
Shelef (Israel) stated that both irradiation and temperature
affect algal productivity. In northern countries, for instance, low
temperatures usually coincide with low irradiance and the combination
results in low algal productivity. The idea that 5-25°C is the
range for algae productivity is correct if the various species of
algae are taken together. There are ocean-dwelling algae that grow
very well at very low temperatures, while other species require
higher temperatures for optimal growth.
With regard to the question of the effect of pond size on
productivity, Shelef (Israel) stated that if the second stage had
been of a larger scale, it probably would have yielded better results.
Because of their size, the mini ponds tend to produce a lot of
shading and lose heat by radiation.
Shelef (Israel) stated that they have used aluminum chloride
as the flocculant at a level of about 100 mgfl and that this added a
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considerable quantity of chloride to the effluent. However, they are
using better flocculants now. One of the most promising is chitosan,
a polysaccharide derivative of chitin which is obtained as a waste
material from the shrimp and lobster industry. Shelef (Israel) men-
tioned that they had tried micro straining; but the algae are too
small for micro straining.
Shelef (Israel) confirmed that algae do absorb heavy
metals. However, they found that the heavy metals, especially those
bound to phosphates, are practically inert and pass through the
animals with minimal absorption. In effect, most of the heavy
metals were recovered in the feces of the animals. In any case, the
animals have a relatively short life (they are slaughtered for food),
and the time available for accumulation of heavy metals in their
tissues is minimal. In effect, there is no heavy metal problem.
Shelef (Israel) noted that $200-$300 (United States) per
ton is the selling price for algae. The cost is less than that for
soybean and fish meals on an equal protein basis. Shelef (Israel)
stated that in northern countries such as Germany, algae could be
grown in the summertime.
Shuval (Israel) asked Shelef (Israel) to comment on the
extent to which nature plays havoc with the consistency of the pro-
cess, especially with regard to the growth of the appropriate algal
species. Shelef (Israel) replied that they have had few major
problems with their system and have operated continuously without
any shutdown.
Parker (Australia) aksed Shelef (Israel) to confirm that
the organic loading on the initial pond is on the BOD order of
300-600 kg/ha«d to indicate the annual cost per unit mass of nutrient
removal. Shelef (Israel) replied that, not considering the invest-
ment, the sale of algae covered only about half of the cost of the
operation. However, because of the production of algae, the total
cost of nitrogen removal was only 50 to 67 percent of that of alterna-
tive methods. Regarding organic loading, the 300-600 kg/hd-d range
was correct. This means that the load on the ponds is four to seven
times greater than that placed on regular oxidation ponds or lagoons
and this requires a lot of area. However, the area required is only
1/4 to 1/7 of that which would be needed for oxidation or stabiliza-
tion ponds.
Sandbank (South Africa) asked Shelef (Israel) if, in the
situations with low nitrogen concentrations, the two-stage systems
would be required. He also asked for comments on the alternative
of removing phosphorus by flocculation instead of a second stage
which would appear to increase losses by evaporation. In addition,
he asked for comments on the application of the AGP bioassay outdoors.
Shelef (Israel) replied that in weaker wastes, such as those
containing 25 mg/l of nitrogen, 80-90% of the nitrogen could be removed.
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He added that phosphorous most certainly can be removed by floccu-
lation, but with the production of a very troublesome sludge.
Shelef (Israel) highly recommended use of AGP tests to ascertain
the necessity for removing a nutrient.
D. Paper No. 22: "Operational Management of Pollution
Incidents—The Thames Way, UK," E. C. Reed,
and M. C. Dart (United Kingdom)
Extension of the concept of integrated river basin manage-
ment to the management of serious pollution incidents and the inte-
grated management system employed in the U.K. to cope with such
multidisciplinary problems were discussed. In addition, the develop-
ment of a floating oxygen unit called the "Thames Bubbler" to im-
prove oxygen levels in the tidal reaches as well as the upper parts
of the Thames was discussed.
Phillip (France) discussed the importance of preventive
measures as a means of reducing the incidence of water pollution
episodes. It was indicated that in the aircraft and space industries,
analyses of systems from the point of view of reliability and safety
are the rule and suggested that those who are responsible for the
operation and maintenance of water supplies should employ similar
methods to reduce the probability of pollution incidents.
Philip (France) mentioned that a tricky problem in incidents
of water pollution is not the sounding of an alarm as quickly as
possible, but the ability to quickly and accurately diagnose a
problem. He suggested that, where applicable, one method which could
be employed in alleviating a pollution event in a river would be to
decrease the concentration of the pollutants to an acceptable level
by adjusting the rate of flow in the river. In this case, it is
assumed that there are a number of storage reservoirs feeding into
the river which could be tapped for this purpose.
IV. CRITIQUE OF SESSION
All papers in this session were of high quality and were
well recieved by the audience as evidenced by informative discussions.
The instrumentaton and techniques discussed in Paper No. 16 appear to
be highly promising both for research and routine analytical pur-
poses with smaller organic molecules (compounds produced by the
reaction of chlorine with amino acids and other low molecular weight
nitrogen-containing compounds). However, no information was avail-
able on the performance of the system with larger molecules. Utili-
zation of the system in conjunction with mass spectrometry (MS) was
discussed. Employing two-dimensional gas chromatography, trapping,
and multiple injections for isolating and concentrating compounds
prior to MS analysis is intriguing and of great promise with regard
to the complete identification of potentially toxic (in the broadest
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sense) substances (especially minor contaminants of high toxicity)
in drinking water.
Bilstad (Norway; Paper No. 18) described a membrane
probe/gas chromatographic method for quantifying dissolved oxygen
and nitrogen. Because the method was dependent upon diffusion, it
is basically static in nature and cannot be utilized for kinetic
measurements. In effect, it would have only limited application
in research in which it was necessary to measure the rate of change
in oxygen concentration either (or both) instantaneously or con-
tinuously. However, the technique appears to be excellent for
quantifying dissolved nitrogen.
Shelef (Israel; Paper No. 20) described a highly efficient
two-stage algal biomass accumulation system for the removal of
nutrients from wastewater. Because the algae contain 40-70% pro-
tein, they can be harvested and processed to yield a high-protein
animal feed or protein for human consumption. Concern was raised
over the possibility of heavy metal uptake by the algae and the
concentration of heavy metals in the protein-rich end product. Al-
though no data were presented, Shelef (Israel) stated extensive
studies have indicated no heavy metal-related problems with the
animal feed. It would have been helpful if the details of these
studies had been presented (including the quantity and kinds of
metals and metal species present in the protein concentrate).
Based on extensive heavy metal toxicology data and data regarding
fish protein concentrates, the innocuity of the algal protein con-
centrate is highly questionable, especially in the case of mono-
gastic animals. On the other hand, because of their food and unique
digestive system, ruminants may be relatively less affected by the
heavy metal content of the algal-derived protein concentrates.
The discussion (Paper No. 22) of the management system
employed in the United Kingdom to cope with major river pollution
episodes was highly informative, and most certainly, not contro-
versial .
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The applicability to United States water pollution research
and monitoring problems of the two-dimensional gas chromatographic
(GC) method for identifying and quantifying organic water contaminants
described by Keith (U.S.A.; Paper No. 16) and the membrane probe tech-
nique for quantifying dissolved nitrogen described by Bilstad (Norway;
Paper No. 18) should be thoroughly investigated. There is, for example,
only limited information on the variety and nature of potentially toxic
(in the broadest sense) chemical contaminants present in low concen-
trations in water used for human consumption. One reason for this has
been the inability to identify such contaminants because their
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presence is masked by other compounds. Another has been the in-
ability to accumulate sufficient quantities of these substances
for characterization. It would appear that many such problems
could be solved utilizing the two-dimensional GC technique,
especially in conjunction with mass spectrometric analysis. It
is to be stressed that identification and characterization of
low-level contaminants in water used for human consumption is of
importance not only because such contaminants may be directly
toxic but also because some may act synergistically with other
contaminants (major or minor) resulting in potential toxicity.
The membrane probe/GC technique for measuring dissolved nitrogen
appears to be especially applicable to surveying/monitoring
environmental situations in which there is a potential for high-
level dissolution of nitrogen which could lead to deleterious
effects on a wide variety of aquatic life (e.g., food/game fish).
Use of two-stage algal biomass accumulation systems for
the removal of nutrients from wastewater (Paper No. 20) may be
highly feasible in a number of specific situations in the United
States and should be investigated for its applicability.
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I. SESSION
A. Day: Tuesday, March 30, 1982
Hall: A
Time: 1:00 to 4:35 p.m.
B. Theme of Session: Microbial Resistance; Wastewater
Ozonation; Wastewater Phenolics
II. REVIEWER
A. Name: P. V. Scarpino
B. Position and Affiliation: Professor of Environmental
Engineering
Department of Civil and
Environmental Engineering
University of Cincinnati
Cincinnati, OH 45221
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 24: "Viability and Adaptability of E. Coti
and Enterococcus Group to Salt Water with
High Concentration of Sodium Chloride,"
by T. Omura, M. Onuma, and Y. Hashimoto
(Japan)
5
„ The authors individually examined the viability of 10 to
10 /ml of freshly isolated E&choA^ickia coti and enterococci in
synthetic sewage (having a BOD of about 100 mg/I) containing
10 g/200 ml of NaCl to bring the concentration of NaCl to 5%
(Wt/V). The survivors were subsequently regrown and inoculated
into similar synthetic sewage containing NaCl to determine the
adaptability of the organisms to salt water. E. coti was more
sensitive to the salt water than the enterococcus group.
S&ieptococccti hazcoJUA var. tiqu&ficuuznd demonstrated the greatest
resistance of viability, and, of the enterococcus group'examined,
S. bazcAim showed the least viability.
Unlike E. coti type I, after repeated exposure of
E. coti type II to salt water, its survival was changed from
that of rapid die-away to one of multiplications. In addition,
as E. coti type II was adapted to salt water it was replaced by
CAJUiobcLcteA. iKenyidii types I and II. Each member of the entero-
coccus group adapted differently to the salt water system. For
example, although S. iatcixm had the poorest viability, it adapted
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well, whereas S. divianA which showed greater viability in salt water
than S. iazcMxm could not be adapted to this environment. Both
S. and S. &a.zcaLLi> var. Liquz&acsLW& also could be adapted
to the salt water.
Types I and II of E. cotc. were detected near a sewage
outfall (Station 1) in Miyako Bay, Japan, but were not isolated
at Station 2 (about one kilometer from Station 1). Since both types
I and II of CsCtnobcicteA. ^KcundU. were detected at Station 2, this
was believed to support the view that E. c.oti type II is adaptable
to salt water. It was suggested that the isolation of E. coti
types I and II may show recent water contamination, whereas the
presence of CiXAoboLctzn. fawncLU. types I or II may show old con-
tamination.
Furthermore, it was suggested that the isolation of
S. divta.ri6 from sea water might indicate recent contamination,
while the presence of S. iazcoJUM and 5. fiaecattd var. tLquz-
6acx.en6, as well as S. latcAjm, may indicate old contamination of
the sea water.
Grabow (South Africa), the invited discusser, pointed out
that the findings of this study were of practical significance
insofar as they indicated that the types of organisms in sea water
can, in fact, give an indication of how far a sampling point is
located from the actual source of pollution. In addition, although
the findings were interesting, it was important that some informa-
tion on the underlying mechanisms involved in adaptation to saline
resistance by the microbes be included. However, the paper did
not give a great deal of information concerning mechanisms of
resistance development. This information is important to evaluate
the behavior of other organisms in this environment and to evaluate
the indicator significance of E. cotc and other coliforms, as well
as streptococci as indicators of fecal pollution of sea water.
The following additional points were made: What has been described
as adaptation were in fact genetically-stable mutations to increased
resistance in an unfavorable environment. Grabow (South Africa) was sur-
prised that closely related bacteria gave different adaptability
(or mutation) responses. He suggested that C-L&iobacteA &teun
-------
genetically stable mutations. Information on the possible dif-
ferences between saline-sensitive and tolerant strains may be
enhanced if more information was available on other properties of
these organisms such as their morphology, growth rate in broth,
the composition of their cell walls, and the ability to grow at
44°C. Grabow (South Africa) concluded by emphasizing that this
paper was important because it was in an area of prime importance,
i.e., the ability of microorganisms to adapt to unfavorable environ-
mental conditions, and related to the selection of resistant strains
which may play an important role in water treatment processes.
Omura (Japan) replied to a question by Filip (Federal
Republic of Germany) conerning the composition of synthetic sewage
by noting that it contained a BOD of 100 mg/£ and included sufficient
nutrients. Filip (Federal Republic of Germany) indicated that E. coti
is used in Germany as an indicator of fecal contamination of swimming
pools filled with sea water and that the resistance of fecal strepto-
cocci to salinity is well known. For example, in normal microbio-
logical diagnostic practices, the growth of fecal streptococci in
nutrient broth containing 6.5% NaCl is used as a characteristic
criterion for the identification and isolation of fecal streptococci.
It was suggested that perhaps another bacterium would be better used
in his studies instead of the fecal streptococci.
Shuval (Israel) noted that the paper was germane at this
time when we are concerned with a particular pathogen that is known
to be quite tolerant to sea water, i.e., the cholera vibrio. The
latter can possibly be transmitted to man via shellfish. Thus, the
search for microbes that mock or parallel such resistant pathogens
is quite germane. However, the primary mechanism for inactivation
of coliform microbes in the sea is not the chemical composition of
the sea water, but is due to light effects (i.e., either photo-
sensitation or photo-oxidation). The actual role of the inactivation1
of coliforms by the composition of the sea water is a relatively
minor factor in the overall protection of beaches. This does not
negate, however, the importance of this present study. Nevertheless,
the salt content of sea water plays only a small part in inactivation
in sea water under real-world conditions. The present studies were
carried out in the laboratory in dark incubators, thus negating the
effect of the light on inactivation. Finally, Shuval (Israel) pointed
out that the nutrient environment provided in the study was too rich
a menstruum for the development of the bacteria. Omura (Japan)
responded that high BOD levels were used in his study to allow the
added bacteria to reproduce, and thus allow easier detection of
bacterial resistant to salt water. Shuval (Israel) replied that he
would like to see studies on the presence of photo-sensitive re-
sistant organisms in the sea.
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Gameson (United Kingdom) replied to Grabow (South
Africa) and pointed out that the effect of radiation on bacterial
mortality in the sea was not confined to the ultraviolet range
only. Long-wave ultraviolet and short-wave visible light (half-
way through the visible spectrum) also has a lethal effect on
coliform bacteria. The shorter the wave length, the greater the
lethal effect, but the smaller the quantity of radiation available
B. Paper No. 26: "Chlorine-Resistance of Coliform-tested
Bacteria Isolated from Raw and Treated
Sewage Effluents," by L. V. C. Leong,
D. Otsaka, H. F. Ridgway and B. H. Olson
(U.S.A.)
Two hundred and seventy-four bacteria, predominately
coliform organisms, isolated from sewage treatment effluents
were screened for relative resistance to combined chlorine using
a disc-assay procedure. Bacteria isolated from tertiary chlori-
nated effluent were the most resistant to combined chlorine
according to the assay procedure. EtchejUckia. coti was the pre-
dominate organism isolated from the unchlorinated sewage treat-
ment processes and ranked fifth of 12 genera in resistance to
combined chlorine, while EnteAobacAvi sp. was the dominant
bacterial genera isolated from chlorinated tertiary effluent and
was the most chlorine resistant.
In formal discussion by Vial (France), the disc-assay
technique for chlorine resistance was questioned. The discusser
asked if the chlorine resistance found was a natural species-
resistance or was it an acquired resistance of the plasmid type.
He pointed out the importance of the phenomenon of microbial
chlorine resistance and its implications. This and other work
should influence attitudes toward disinfection of wastewater
because of the possible selection of microbes which are chlorine
resistant. Thus, he was skeptical about the disinfection of
wastewater since it might scatter in nature resistant strains of
not only fecal indicators but also pathogens. Also, the develop-
ment of resistant microbes might make it difficult to treat
effluents later on if it is absolutely necessary to do so.
Leong (U.S.A.) responded that chlorine resistance was
genetically stable since the growth of the initially isolated
chlorine-resistant bacteria went through several passages and
still maintained a resistant pattern. The exact mechanism of
resistance (i.e., plasmid associated or otherwise) is unknown
at this time.
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Filip (Federal Republic of Germany) emphasized that he
was skeptical of chlorination of effluent, although some
(but not all) pathogens are inactivated. Chlorination cannot
only cause the development of chlorine-resistant microbes,
but the process can as well cause mutagens to be formed. Filip
(Federal Republic of Germany) also questioned the technique used
to evaluate chlorine resistance. Also, the authors of the paper
did not carry out any genetic tests but still claim the development
of genetically-stable bacteria.
Leong (U.S.A.) pointed out that although the test
technique used might have flaws, it is extremely useful in
screening large numbers of bacterial colonies for chlorine
resistance. Grabow (South Africa) had reservations about the
test techniques used to establish chlorine resistance. He
pointed out that the process described is one of selection,
not of mutation.
C. Paper No. 28: "Ozonation of Aromatic Compounds:
pH-Dependence," by E. Gilbert
(Federal Republic of Germany)
The ozonation of 2-nitro-p-cresol and p-toluenesulfonic
acid (C = 1 mmole/£, ozone dose = 10 mg/min.£) in aqueous solution
tion as a function of the pH-value (pH = 2.5 - 10.5) was investi-
gated. At a pH of 2.5, the reaction products of 2-nitro-p-cresol
were measured quantitatively over the run of the reaction.
Elimination rates for initial compounds and the minerali-
zation of the heterogroups increased with pH value. On account
of this result, the spectrum of oxidation products is different
after 90% elimination of the initial compound as a function of pH.
The values of DOC- and COD-elimination increased with increasing
pH. Although the ozone absorption was better in the basic range,
1.6 - 2.2 mg 03/mg aCOD are required in the basic range (pH 10),
but only 1.1 mg 03/mg aCOD in the acid range (pH 3).
Gilbert (Federal Republic of Germany) discussed ozonation
of substituted aromatics in aqueous solutions, how reactions involving
ozone proceeded, and which reaction products could be expected, de-
pending upon the elimination of the initial compound and the pH value.
Besides, he examined how much ozone was needed to eliminate the COD
and to increase the BOD values.
The invited discusser, Schalekamp (Switzerland), reviewed
the highlights of the paper. He emphasized that the most important
results of this study were: In the ozonation of aromatic substances
in aqueous solutions, the pH value plays a very important part, i.e.,
the rate of elimination of aromatic compounds increased with rising
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pH, along with a 2-1/2 times increase in the degradation of DOC
and COD and the mineralization of the hetero groups. Earlier
research demonstrated that other organic substances, e.g., humic
acids, are better eliminated by ozone at a higher pH value. Thus,
a higher pH value of the water means better oxidation. Additionally,
because the pH value plays such an important role during the ozona-
tion of the organic compounds, it is absolutely necessary when com-
paring the results of ozone effects to indicate ozone dose and con-
sumption and the corresponding pH values of the investigated
aqueous solutions.
D. Paper No. 30: "Presence of Phenolic Compounds in Sewage,
Effluent and Sludge from Municipal Sewage
Treatment Plants," by F. B. DeWalle,
D. A. Kalman, D. Russell, D. Norman,
E. S. K. Chain (U.S.A.)
A total of 25 municipal sewage treatment plants were
sampled, 10 of which were resampled, to determine the quantity of
phenolics in sewage, final effluent and anaerobically-digested
sludge using capillary GC/MS/DS techniques. The study noted in
decreasing order of frequency in raw sewage: phenol, pentachloro-
phenol, dimethylphenol, 3-methyl, 4-chlorophenol, 2,4,6-trichloro-
phenol, 2,4-dichlorophenol, 2-nitrophenol, 2-chlorophenol,
2,4-dinitro-6-methylphenol and 2,4-dinitrophenol. The maximum
concentration of phenol in sewage and sludge was 2800 ppb and
4460 ppb, respectively, while similar values for pentachlorophenol
were 58 ppb and 1200 ppb. Statistically calculated concentration
reductions for phenol and dimethylphenol were generally greater than
noted for tri- and pentachlorophenol. Low decreases or increases
were noted for monochlorophenol and especially for dichlorophenol
as a result of the chlorination of the final effluent.
Osborn (South Africa) presented the formal discussion
and raised several points dealing with the sensitivity of the
detection method. He pointed out that although the authors indi-
cated that higher influent concentrations of phenol resulted in
a higher residual phenol concentration in the effluent (attributed
to a possible toxic effect), this did not seem likely since
activated sludge has been frequently used for the treatment of
effluents high in phenol from coal gasification.
IV. CRITIQUE OF SESSION
The papers in this session were not uniform in either
theme or in quality. Papers No. 24 and 26 dealt with the develop-
ment of salt-resistant and chlorine-resistant microbes, respectively.
The authors discussed the development of resistance, but in one case
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resistance was believed to occur by adaptation (Paper No. 24),
whereas in the other resistance was acquired by a selection pro-
cess that produced genetically stable bacteria (Paper No. 26).
Paper 24 was at one point a rediscovery of the use of NaCl to
isolate streptococci, and, along with other problem areas, pointed
out an important fact, that although the investigators had an
excellent purpose, they were not microbiologists. Paper No. 24
elicited a vigorous floor discussion, in spite of itself.
Paper No. 26 was a valuable contribution to the litera-
ture and was well received by most of the delegates. However,
there was criticism of their use of "genetically stable" without
sufficient proof to several that this was so.
Paper No. 28 was the masterpiece of the session. Gilbert
(Federal Republic of Germany) carefully unfolded an excellent, well-
constructed scenario highlighted by excellent slides and a good manner
of presentation.
There was much to congratulate Paper No. 30 about, but
some were dissatisfied with the methodology used. However, most
felt that it was a definite contribution to the literature in this
area of phenol removal. It was unfortunate that no microbiological
investigations were conducted at the same time since they might
have proven invaluable in an understanding of the removal efficien-
cies.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
All of these papers are a contribution to the literature,
and we can learn much from them. Papers No. 24 and 26 focus atten-
tion on the important area of development of resistant microbes,
whereas Papers No. 28 and 30 deal with the interaction of ozone with
substances in water and the presence and movement of phenols through
municipal sewage treatment plants, respectively.
Papers No. 24 and 26 point out the need to more thoroughly
be aware of the developments under stressful conditions of resistant
microbes in the water environment, either by a selection, adapta-
tion, or actual mutational process. It will be important to know
more about resistance developments in natural or man-made environ-
ments, since pathogenic-resistant microbes can ultimately be a
danger to the public. Several times adverse comments were made by
delegates about chlorination of sewage and the possibility of
producing resistant pathogens. It is important that we assess
such developments to determine their real costs and benefits and
to re-evaluate procedures if warranted.
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The results of Paper No. 28 will find increasing use-
fulness as we further examine the use of ozone to remove organic
compounds from wastewaters. The work of this author should be
carefully followed, since he is carefully investigating the
factors affecting ozone interactions with compounds.
The last paper, Paper No. 30, provided useful information
to those in charge of industrial effluents since it focused on
the removal of phenols through treatment plants. As we clean up
our influents to treatment plants, such information will continue
to be increasingly valuable.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: A
Time: 9:00 a.m. to 12:30 p.m.
B. Theme of Session: Assessment and Control Strategies
for Water Quality Management
II. REVIEWER
A. Name: A. J. Englande, Jr.
B. Position and Affiliation:
III. DESCRIPTION OF SESSION PAPERS
Associate Professor and Chairman
Department of Environmental
Health Sciences
Tulane University School of
Public Health and Tropical Medicine
New Orleans, LA
A. Paper No. 32: "An Appraisal of the Performance of a Con-
tinuous Automatic Fish Biomonitoring System at
an Industrial Site," by W. S. 6. Morgan, P. C.
Kuhn, B. Allais and G. Wallis (South Africa)
The paper described the application of a continuous auto-
matic fish biomonitoring system employing fish locomotory behavior
patterns as measured by means of ultrasonic echoes to monitor acute
toxic discharges from a pulp and paper mill. The system was capable
of monitoring either five or ten independent channels, each con-
sisting of a specifically-designed sensor chamber containing one
fish (guppy) through which a continuous flow of test water was
passed.
The guppy was selected as the sensor fish due to its sensi-
tivity to a wide variety of pollutants and its ease of maintenance.
Increased fish activity (counts/h) above the 95% confidence limits
established for normal activity levels indicated a potential toxic
condition. Feed water consisted of river water upstream of the
plant, dechlorinated influent mill water, and mill effluent diluted
to a concentration equivalent to that of lowest recorded river flow.
Advantages of the biomonitoring system included:
(1) continuous, immediate response to toxic spills versus the non-
continuous output of physical-chemical analyses; (2) response to
the totality of the environment considering synergistic and anta-
gonistic actions; and, (3) response to acute toxicity as well as to
some chronic toxicants.
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During the twelve months of evaluation, only one fish
kill was experienced in the river of study. Information from the
sensors helped regulatory officials to conclude the industry was
not responsible, hence avoiding possible litigation. Cost of
system installation was approximately R35.000 ($35,000 U.S.A.); whereas
operation and maintenance costs totalled R3,350 during the year of the
study. Enhanced public relations for the industry were a benefit.
The formal discusser, Yoshida (Japan), noted that con-
tinuous biological monitoring was essential and equal in importance
to chemical analysis in assessing impact to the aquatic and human
ecosystem. From an ecotoxicological viewpoint, organisms employed
should represent those common in the food chain within the eco-
system, including single-cell algae, daphnia and fish. In Japan,
fish are commonly used as sensors to toxicants since fish represent
a major portion of protein supply. While fish are easier to evaluate
than many organisms, it must be noted that response to toxicity is
dependent on physiological conditions, e.g., species, age, sex,
spawning, and nutrition. The discusser also indicated that in Japan,
the systemized methodology presented by the author is generally not
practiced. Fish are typically observed visually for toxic effects
in ponds and drainage channels containing industrial effluent. The
species employed is selected based on the specific industrial waste-
water.
The discusser commented on the low dissolved oxygen con-
tent of the mill effluent (3.3 to 2.4 mg/£) and to lack of control
of water temperature. He also noted that the visible light beam
method was usually used to monitor locomotion, and that more data
are needed to evaluate the effects of fish sensitivity to ultrasonic
waves.
Morgan (South Africa) agreed with the concept of considering
a multitude of species (the guppy was more sensitive than other fish
downstream in this case) and using a battery of biomonitoring tests
which are done at the National Institute for Water Research. Under
the conditions of this study, as much standarization was done as
possible, i.e., use of only males. He also replied that the oxygen
content was maintained at a level of that existing below the dis-
charge point and not that of the mill effluent. The author noted
that toxicity varied with temperature and, therefore, it was more
accurate to use ambient temperatures. No effect due to ultrasonic
waves on fish physiology was noted following a six-month exposure.
It was emphasized that it is important to determine where biological
monitoring fits into control situations and into legislation, par-
ticularly for industries who apply for permit exemption. It was
emphasized that the method reported eliminated the observor and
indicated stress on the sensor animal which yielded advanced warning
of critical conditions.
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In floor discussion, Jones (Canada) questioned the type
of toxicity which was measured. He also noted that a direct and
linear relationship was assumed between concentration of toxicant
and fish activity, and that toxicants may reduce activity which
would not be measured by the system proposed. Jones (Canada)
stated that increased temperature may cause a false alarm due to
increased metabolism. Morgan (South Africa) replied that the method
did not detect genetic effects, but measured only acute toxicity and
some chronic effects. Metabolic variance in fish was considered by
a lengthy standardization process. It was noted that a running statis-
tical method (i.e., day to day) could be employed but would be expen-
sive.
In other floor discussion, Josso (South Africa) commented
that while the reported system was excellent, it was only a warning
method which identified pollution, as do other systems. He concluded
that no specific system should be included in the Water Act to force
people to use a unilateral approach.
Handleman (U.S.A.) questioned whether the method proposed
was sufficiently sensitive to detect trihalomethanes or other par-
ticular constituents of concern at the site of evaluation. Morgan
(South Africa) replied that bleaching was not practiced at the
site; therefore, THMs were not a problem.
From the floor, Haboll (South Africa) asked what was the
lowest concentration of toxicants which could be detected by the system.
The author answered that generally, 10% of the lethal level (96-h LCgg)
is detected, but no absolute concentration can be given.
One participant inquired about the preferred ultrasonic
frequency. Response from one of the authors indicated that 100 kilo-
hertz was selected at 1 milliwatt. These frequencies were selected
based on preliminary test results and availability of suitable
sensors.
B. Paper No. 34: "Examination of a Drinking-Water Supply for Muta-
genicity," by P. 6. van Rossum, J. M. Willemse,
C. Hilner and L. Alexander (South Africa)
The paper described the results of an Ames-test survey of
drinking-water sources in Pretoria. Single samples were tested from
18 locations and water constituents from an additional sampling point
were analyzed for mutagenic effects monthly over an eight-month period.
'Characterization Tests' of each sample consisted of pH, chlorine,
optical density and electrical conductivity determinations. After
unconcentrated water samples indicated no mutagenicity, subsequent
samples were concentrated by passage through XAD-2 resin columns
followed by desorption with acetone.
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Mutagenic activity was observed in samples from 14 of
the 19 sampling points as well as consistently demonstrated in the
monthly testing. All mutagenicity was observed with strain TA 98
and was not detected with strain TA 100 indicating that the mutation
was frameshift. Mutagenicity was observed to a greater extent in
plates without the S-9 enzyme activation system, which may indicate
a detoxification or inactivation by these enzymes. No correlation
was found between mutagenicity and volatile halogenated organics,
polynuclear aromatic hydrocarbons, or 'characterization tests'
results. Liquid-liquid extraction samples gave essentially the same
mutagenicity results as those with the adsorption extraction method.
The formal discusser, Hartemann (France), commented that
the results were not in total agreement with those from his research
experiences in France. His remarks took the form of a series of
questions which included: (1) Was follow-up work done to identify
the mutagenic compounds by GC/MS?; (2) Is the mutagenic activity
decreased by activated carbon or ozonation?; (3) Were the Ames
test results confirmed by other tests?; (4) Were other elutriates
aside from acetone evaluated?; (5) Which toxicity tests should be
employed for preliminary screening?; and (6) How does one express
mutagenic activity at different concentrate dilutions? Hartemann (France)
concluded by underscoring the lack of correlation between muta-
genicity and the presence of chlorinated compounds. He also indi-
cated he was disappointed that the authors did not cite the work
of the group in the Netherlands.
In response, Van Rossum (South Africa) replied
that since the work reported was completed, concern has shifted to
isolating the substance(s) causing the mutagenic activity. Work
has focused on developing an extraction procedure considering sta-
bility, volatility and whether the compound is neutral, acidic
or basic. Results indicated that compound(s) producing mutagenicity
were probably organic acid(s). The resin was changed to XAD-7
which yielded slightly better results. The compound(s) were sorbed
to activated carbon and not desorped with acetone. No work was
done with ozone. Other toxicity testing was done including tissue
culture. Acetone was used due to its low boiling point and to pre-
vent artifacts and contamination. The negative results observed
with TA 100 as compared to TA 98 corresponded to those obtained by
Hartemann.
Philip (Federal Republic of Germany) commented that use
of more than one sample from each location would increase the con-
fidence of the conclusions, to which the author agreed. In addition:
(1) What non-mutagenic solvents were used?; (2) Why were mutagenic
activities higher without the S-9 mixture?; and (3) Could UV absorbance
be a function of mutagenic activity? van Rossum (Federal Republic of
Germany) replied that acetone was used for adsorption extraction and
dichloromethane for liquid/liquid extraction. After obtaining
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preliminary results, adsorption extraction was determined to be
the preferred method. He also indicated that increased mutagenicity
without the S-9 enzyme activation system may suggest a detoxifica-
tion or inactivation by these enzymes and therefore the isolated
constituent(s) may not pose a health concern.
Grabow (South Africa) made several comments from the floor.
These included: (1) the XAD extraction procedure is selective and will
not concentrate certain compounds, particularly, very polar compounds;
(2) If one uses non-concentrated water, mutations can be achieved
with both TA 98 and TA 100 strains; (3) If toxic effects do occur,
one can dilute to non-toxic, but mutagenic levels, and draw a
dose-response curve; (4) Good correlations were achieved between the
Ames test results and those from tissue culture; (5) THMs were not
measured by the technique used for the Ames test since volatiles
were lost when samples were evaporated to dryness; and (6) Organic
compounds in water do increase UV sorption and mutagenic activity.
C. Paper No. 36: "Depositional Process of Fine Sediments,"
by T. Kusuda, T. Umita, K. Koga, H. Yorozu
and Y. Awaya (Japan)
Depositional properties and projected sediment quantities
were determined from experimental and theoretical studies using fine
less-cohesive sediments (silt) typical of Japanese estuaries and bays.
The experimental apparatus consisted of a rotating annular channel
and an annular ring. The ring was rotated in the opposite direction
to the channel at related speeds with regard to different shear
stresses to minimize secondary current effects.
The suspended fine sediment concentration was found to
depend on shear stress with critical particle diameter corresponding
to shear stress. The steady-state concentration (those particles
remaining in suspension) at the final stage of deposition was deter-
mined by the quantity of particles smaller than those possessing the
critical diameter. The deposition rate of sediments was found to
be predictable and dependent on size distribution, critical diameter
and concentration of settleable sediments. Sedimentation occurred
rapidly within 22 hours. The suspended particles smaller than the
critical diameter were observed to be held in water without settling
for extended periods.
The formal discusser, Davis (South Africa), considered the
work to be reliable and valuable within the constraints of the experi-
ment. His question dealt primarily with applicability of the proposed
model. Since most estuaries and bays undergo daily tidal changes,
the velocities and shear stresses are dynamic; consequently, deposition
rates and quantities are constantly changing. It was noted that re-
suspension of the sediment was not considered by the authors, thus,
neglecting an important phase of the process.
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The author responded that shear stress does change with
time due to velocity changes; hence, critical diameter and the final
suspended concentration also change. However, some estimation of
deposition can be obtained by using an equation presented in the
paper. He also noted that while erosion does occur, particles
settle readily following reduction in velocity.
Simpson (South Africa) questioned the details
of the annular flume operation which was explained by the author.
He also questioned the particle size distribution measurement
technique and specifically, whether any measures were taken to remove
chemically sorbed contaminants from the silt or if apparent size
was reported. The author responded that a hydrometer test, which
utilizes a rotating disk to measure size distribution by use of
centrifugal force to accelerate the settling velocity, was employed
to determine particle size distribution.
D. Paper No. 38: "Nutrients and Algal Growth in an Impounded
River. Consequences for Its Oxygen Balance
and Nutrient Control Strategy," by K. R. Imhoff
and D. R. Albrecht (Federal Republic cf Germany)
It was reported that a series of impoundments on the final
45 km of the Ruhr River caused heavy algal blooms which proved detri-
mental to the treatment capacity of downstream water works. Phos-
phorus, nitrogen, and organic carbon concentrations were high and
an oxygen shortage was recorded in the river following algal decay
at low flows which required artificial aeration. A balance of oxygen
supply and consumption indicated that 2/3 of the oxygen demand was
due to algal decomposition. Assessment of water quality data from
the past 30 years as well as results from special laboratory evalua-
tions indicated that phosphates initiated algal growth. A phosphate
model was developed for the river which predicted phosphate content
for the years 1988 and 1998. It was projected that by the reduction
of phosphate, maximum algal growth could be cut by about 50%. This
assumed a phosphate concentration of 0.5 mg/£. Capital investment
for phosphate reduction by chemical precipation was calculated to
be low and was, therefore, encouraged.
The first formal discusser, Rivas (France), questioned
whether the most cost-effective method of dealing with the problem
would be the elimination of nutrient problem at the source or at
the water treatment plant. The first approach was recognized as the
most desirable. Questions dealt with the oxygen balances, artifical
aeration and whether ammonia removal would be more successful in con-
fronting the eutrophication problem. The author replied that five con-
tinuous oxygen measurement stations were evaluated on a daily basis.
He also noted that artificial aeration was only provided when the
oxygen level dropped below 4 mg/£. Nitrogen content was not con-
sidered a limiting factor based on data and experience.
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Vivier (South Africa) was impressed with the
monitoring and control of the reported control system. Critical
areas of questioning included: (1) Modeling of limnology
processes in impoundments with short detention times; (2) Quantita-
tive account of algal removal vs costs; (3) Laboratory evaluations
vs actual P-removal and (4) cost/benefit analysis. The author replied
that the model proposed was based on data collected for the system
considered. Precipitation of phosphorus was only necessary during
low-flow conditions and could be accomplished at a relatively low
cost.
Moller (Federal Republic of Germany) questioned the type
of treatment proposed for P-removal. Imhoff (Federal Republic of
Germany) responded that larger activated sludge plants should first
be modified to reduce the critical nutrient.
IV. CRITIQUE OF SESSION
The session dealt with various assessment and
control strategies for water quality management. Owing to the wide
variety of topics covered, each paper will be critiqued individually.
Paper No. 32. If there are good experimental data to
prove that there is a true cause-and-effect relationship between
a specific pollutant and some aspects of behavior, then the bio-
monitoring system as described (and with the limitations so stated)
is a useful idea. However, only acute toxicity of the effluent in
general can be assessed. Morgan et al. (South Africa) recognized after a
one-year trial that effluent concentrations having a long-term
chronic effect, may or may not be detected by in-plant biomonitoring
system, and have initiated work on growth and reproduction. One
must await evaluation of new data before a proper determination of
these aspects can be made.
The authors emphasized the effluent treatment improvements
effected at the paper mill between August, 1979 and August, 1980.
While improvement with respect to COD was made, there was no improve-
ment in reduction of suspended solids or dissolved solids. It is
suggested that increased use of secondary treatment be encouraged
on the theoretical premise that the additional treatment would result
in an improved dissolved oxygen profile (and lower BOD) and ultimately
an improved and more rapid rate of growth for native fish in the
Tugela River.
Paper No. 34. The paper reports good preliminary work
which was well perceived and thought out. The procedure employed
has been previously used to concentrate mutagens from the urine of
cigarette smokers. Taking multiple samples is an important aspect
of any environmental assessment. However, mutagenicity assays were
done on only one of every three samples. The statistical significance
of the results would be greatly increased if all samples had been
assayed.
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The use of columns to remove and concentrate organics from
large volumes of water is very promising. However, as indicated
by the results, the column used for this study did not adsorb all
mutagenic compounds since passing the water through a second column
occasionally yielded significant mutagenic activity. An assessment
of the recovery efficiency (possibly using TOC) would help in
evaluating column adsorption as a viable concentration procedure for
mixed environmental samples.
It would be more legitimate to state that this mutation
is a frameshift, if all four commonly-used Ames strains had been
used in these assays. This reduces the problem of the varying
sensitivities observed among the strains. No speculation is offered
as to the lack of correlation between levels of halogenated organics
and polycylic aromatic hydrocarbons and mutagenicity results. This
could be an example of synergism and/or the presence of promoting
agents in the water which would augment the mutagenic activity of
low level mutagens.
Paper No. 36. The study represented an excellent initial
stage of determining sedimentation and erosion mechanisms in bays
and estuaries. Laboratory and theoretical work will ultimately
have to be tested for practical application where dynamic conditions
occur. Further work on describing the erosion process will undoubtedly
be required to complete model applicability.
Paper No. 38. A data base of 30 years combined with the
results from special laboratory evaluations strongly support the
conclusion that phosphates were responsible for initiating algal
growth for the Ruhr River. It must be noted, however, that selection
of phosphorus, nitrogen, carbon, or other parameters as the critical
nutrient for control will be site specific depending on the water body
under consideration.
The oxygen balance technique vividly illustrated problem
identification and necessary control measures to be initiated. There
is concurrence that control of the problem nutrient should be done
at its source. Applicability and final evaluation of the phosphate
model accuracy can only be determined following implementation of
phosphate control measures.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The information presented during this session dealt with
various aspects of assessment and/or control strategies for water
quality management. The four papers significantly contributed to
existing knowledge in this area and all, to at least some extent,
are applicable to on-going research activities in the United States.
Papers will be addressed separately.
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Paper No. 32. The proposed system is relatively inex-
pensive and requires minimal skill in operation, thus rendering
it of wide potential applicability throughout the United States
for specific industrial discharges. It can indicate continuous
acute, synergistic and antagonistic lethal biological effects
of effluents to specific fish species. While output limitations
may be significant, it does offer an additional tool useful in
water quality management.
Paper No. 34. There has been increased concern in
the United States about the presence of suspected mutagens
and carcinogens in the drinking water of many industrialized
areas, but work in this area has been limited. This paper pro-
vided further evidence that mutagenicity screening is an important
aspect of water quality management. The procedure as discussed by
the authors would be an ideal prescreening assay which would
indicate whether further isolation and identification of specific
compounds is necessary. The paper demonstrated the need to examine
the mutagenic potential of potable water where there is suspicion
of contamination by waste organics.
Paper No. 36. Where sediments are largely of non-
cohesive sediments (silt), the study provided insight into the
significant parameters which affect sediment deposition. This is
of importance in hydrodynamic studies and coastal engineering
evaluations. The maintenance of desired water depths for naviga-
tion is of course critical to the shipping industry of the United
States and other countries of the world. This work is particularly
applicable to river outlets and estuarine areas where silt
predominates.
Paper No. 38. Monitoring and system control reported in
this paper is impressive and perhaps could be employed at site-
specific locations within the United States. The method of problem
identification appears to have wide applicability; however, phos-
phorus will not always be the controlling nutrient. Other factors
(physical, chemical and biological), besides nutrient content,
must be considered. Much money is spent annually for nutrient
control within the United States without comprehensive evaluations
for justification. This study is useful for designing and imple-
menting such comprehensive assessments.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: A
Time: 2:00 to 5:35 p.m.
B. Theme of Session: River Water Quality; Sediment-Water
Interactions
II. REVIEWER
A. Name: Gerard A. Rohlich
B. Position and Affiliation: Professor of Environmental
Engineering
University of Texas
Austin, TX
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 40: "Impact of Nuclear Power Plants of the
PWR-Type on River Water Quality," by
W. J. Masschelein and J. Genot (Belgium)
The paper summarized and analyzed the impact of a
pressurized water reactor (PWR) nuclear power plant on water quality
in the Meuse River. The river is the raw water source for about
5 million persons in France, Belgium and the Netherlands. The data
were based on five years of experience at the Tailfer water treat-
ment plant in Belgium. The Tailfer plant is located 48 km downstream
of the PWR nuclear power plant of 320 MW(e) located at Chooz. A
principal purpose of the study is to provide guidelines for examina-
tion of the impact that installation of additional nuclear plants,
now in the planning stages and totaling 5400 MW(e), will have on
water quality in the Meuse River. Four impact factors were con-
sidered including: (1) reduction in water flow; (2) thermal impact;
(3) discharge of nuclear active effluents; and, (4) physico-chemical
impact through enrichment in salts and suspended matters.
Analysis of the hydrologic data indicated that, when
full capacity of the power plants at Chooz is realized, the immediate
loss in water flow in the river may amount to 4 m3/s. This is equal
to an annual loss in flow of 87 x 10& m3. This deficit was con-
sidered to be critical for navigation, industrial, and general uses
downstream and would have to be restored by appropriate reserves so
as to maintain the required flow conditions. The installation of
PWR power plants of high capacity, requiring cooling water from
rivers subject to low-water levels such as the Meuse, would make it
necessary to provide sufficient storage to provide adequate water
flow downstream of the power plants.
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At full power-plant capacity at Chooz, the increase in
water temperature at Tailfer was predicted to be less than 1°C
and generally about 0.5°C. The amplitude of the temperature in-
crease at Tailfer will be within the normal variation of the diurnal
cycle. Although as yet there has been no definite indication of
effect of temperature on the biota in the river, the authors recom-
mend that water temperature immediately downstream of the nuclear
site (e.g., 1 km) not exceed 30°C and see a potential need for
installations to provide supplementary water to the river flow to
guarantee that the 30°C limit is not exceeded.
Tritium activity in the Meuse River was measured every
two to three days in "average" samples, and particle-fixed radio-
activity was measured monthly on samples collected continuously.
Chemical pollutants from the power plant mainly derive from the
cooling and heat transfer circuits. The principal products of con-
cern are chlorinated compounds, trihalomethanes (THM), and sulfate
(resulting from use of sulfuric acid for de-scaling).
Using the data obtained over the five-year period as a
basis for prediction of water quality when proposed power plants
are fully developed, the authors propose the following guidelines:
(1) Accurate information is required on average and
duration curves of water flow and particularly instantaneous flows
from power plant during critical low-flow periods in the river.
(2) The most active effluents including tritium appear
sufficiently low in volume to consider their transport to other sites.
(3) River water qualitv should be based on measurement of
tritium, total y activity and Co6*, Cs 137t Mn$4, C058, and Csl34.
(4) License for nuclear discharge should be based not
only on "maximal admissable dose" over an integrated period, but
also on "instant maximal volume concentrations."
(5) Anti-fouling treatment through pulse chlorination is
a questionable practice producing THMs at levels higher than accept-
able.
The invited discusser, Henry (Australia), expressed the
opinion that biological effects of the power plant discharges
should be given more attention. Changes in the biological community
may affect the ability of the biota to take care of other discharges,
and if a viable fishery exists, it could also be affected adversely.
The author responded by stating that the Meuse is used for sport
fishing but there is no commercial fishery, and that as yet there is
no clear evidence that the biological community has been affected.
There is some evidence that tritium in algae is 15 percent higher
than the water column.
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The author reported that the radium content of the intake
water at the Tailfer plant was 0.08 nCi/m^. In response to a question
as to what portion of this was natural, the author stated that the
natural level was 0.02 nCi/m3, and thus the maximum contribution from
the present power plant was 0.06 nCi/m^. A question was asked con-
cerning the amount of wastewater from the power plant from leaky
valves and fittings that was not being monitored. This amounts to
about five percent, and radioactivity in atmospheric fallout amounts
to less than ten percent of the total liquid discharge.
B. Paper No. 42: "Fractional Composition of Phosphorus
Forms in Sediments Related to Release"
by H. Furumai and S. Ohgaki (Japan)
The purpose of the study was to investigate the characteris-
tics of the various forms of phosphorus in sediments in an effort
to clarify the relation between the fractional composition of the
phosphorus forms and phosphorus release.
Two series of experiments were conducted, one using sedi-
ment samples taken from Takahama Canal near Tokyo Bay. The canal
receives about 10fe m^/d of effluent from a secondary sewage treatment
plant. The water in the canal is a mixture of sea water and effluent.
The second series used sediment samples from Lake Kasumigaura, a
eutrophic lake which receives a heavy load of organics and nutrients
from polluted rivers.
Phosphorus release from sediments was investigated by
placing sediment samples in bottles and incubating the samples in
the dark at a constant temperature of 30°C. The canal samples were
covered with artificial sea water, and the lake samples with filtered
lake water. In the series using sediment from the canal, five samples
each with one added phosphate compound and a control were investigated.
Phosphate compounds added were KH2PO4; Fe3(P04)2-8H20; FeP04*4H20;
A1PO4-2 HgO;and Cai0(PO4)6(OH)2• The lake sediment samples were
sliced from cores and sediments from depths of 0-4 cm, 6-10 cm, and
20-24 cm were used. Phosphate compounds were not added to the lake
sediment samples.
After a predetermined and varying number of days, overlying
water was withdrawn by pi pet, filtered and analyzed. Sediment was
then centrifuged at 300 rpm for 10 min and supernatant liquid removed.
Centrifuged sediment was used for phosphorus fractionation. The
procedure for phosphorus fractionation was a modification of that
developed in the field of soil science and consisted of extraction
using 1.0 N NaOH and 1.0 N HC1. Iron and aluminum phosphate and
adsorbed phosphorus were recovered in NaOH-extractable orthophos-
phate (Na0H-0-P) fraction, calcium phosphate in HC1 extractable
orthophosphate (HC1-0-P) fraction, and organic phosphorus in NaOH
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extractable total phosphorus except for orthophosphate fraction
and residual fraction. The results showed that the NaOH-extractable
orthophosphate (NaOH-O-P) fraction was the main constituent of
sediment phosphorus, and that this fraction was the form most easily
released under anaerobic conditions. From their studies the authors
concluded that the potential for phosphorus release from sediments
was closely related to the amount of the NaOH-O-P fraction present
and was thus an index of the release potential.
Bruwer (South Africa), the invited discusser, stressed
the practical importance of an understanding of the forms and
quantities of phosphorus release from sediments in developing a
rational program for management of lakes. It is possible that in
some situations the contribution from internal sources, in a lake
for example, may provide sufficient phosphorus to support growth
and kept water quality down and raise questions as to the economic
feasibility of removing phosphorus from external point sources. A
key point, however, is to determine the fraction of phosphorus that
is biologically available. It would be desirable to expand the
study being conducted to include bioassay procedures relating
phosphorus that is biologically available. It would be desirable
to expand the study being conducted to include bioassay procedures
relating phosphorus release to phosphorus utilization. Bruwer (South
Africa) expressed concern about prolonged storage of samples at 4°C and
referred to studies which showed that the NTA-extractable fraction
doubled after a storage period of three to four months at 4°C.
The authors responded that they stored samples for one month and
elected not to freeze samples because such treatment would destroy
the structure of the sediments. Bernhardt (Federal Republic of
Germany) pointed out that the index was limited to release
under anaerobic conditions but that release can also take place
under aerobic conditions and extension of the studies to include
aerobic release would be desirable. The authors agreed with the
suggestion but pointed out that their studies indicated much higher
concentrations of phosphate in the anaerobic interstitial water
than in overlying aerobic water.
C. Paper No. 44: "The Influence of Sediment Water Interactions
in an Impoundment on Downstream Water Quality,"
by T. J. Grizzard, C. W. Randall, and
E. M. Jennelle (U.S.A.)
The general purpose of the research was to evaluate sediments
as a source of plant nutrients. In addition, a specific investigation
was made to determine the role of sediments in regulating phosphorus
supply in the overlying water column and to assess the water quality
impact of the presence of a small upstream impoundment on a large
downstream reservoir. The reservoirs are located in southwestern
Virginia and the upstream impoundment (Niagara Reservoir) received
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11.4 x 10 m /d of secondary wastewater treatment plant effluents
which contributes 64 percent of the phosphoruis entering the basin.
About one-half of the surface drainage entering the downstream
reservoir (Smith Mountain Lake) must first pass through the
Niagara Reservoir.
Sediment and water quality sampling stations were
established in the Niagara Impoundment and analyzed to determine
inorganic phosphorous fractions using modified Chang-Jackson
extraction procedures. Laboratory studies on sediments were carried
out in cylindrical reactors, 19 cm in diameter and 38 cm long.
The reactors were provided with mixing equipment, air diffusers,
and platinum electrodes for measuring electrode potential in the
water column and in the sediment. The reactors were operated in
the dark at 20°C and the studies were designed to assess the effects
of the following on plant nutrient behavior: (1) surficial sediment
constituency; (2) exposed surficial sediment area; (3) water column
and sediment electrode potential; and (4) water column phosphorus
concentration.
Seasonal changes in the character of the surficial sedi-
ments of the Niagara Impoundment were observed through the analysis
of a time series of samples collected over a 15-month period. Al-P,
Fe-P, and reductant-soluble sediment phosphorous declined during
the summer months, indicating a release to the water column. At the
same ti.ne, a dramatic decline in extractable iron of the sediment
prompted the conclusion that the primary release mechanism was
anaerobic destruction of insoluble ferric iron compounds followed
by liberation of sorbed and precipitated phosphorus species. In
the overlying water column, iron and phosphorus concentrations
showed increases of 1.0 and 0.8 mg/I, respectively, through a
reach of the Niagara Impoundment during the summer and, conversely,
concentrations were observed to decrease during the winter and
spring. Aerobic-anaerobic reactor studies demonstrated that large
quantities of phosphorus could be stored in surficial sediments
when oxygenated and subsequently released during anoxic conditions.
The active portion of the sediment-water interface was found to
extend an average of only 2 mm into the sediment profile. The
results showed that phosphorus exchange was essentially a surface
phenomenon and that the net amount of phosphorus adsorbed de-
creased with decreasing surface area under aerobic conditions and
that similarly regeneration under anaerobic conditions was decreased.
The authors concluded that the sediments of the Niagara
Impoundment tend to redistribute the annual nutrient load entering
the basin, raising the concentrations of phosphorus in the outflow
during the critical growing period in the summer and thereby con-
tributing to water quality degradation in Smith Mountain Lake.
Effective reduction of phosphorus to the lake could be achieved
by maintaining aerobic benthic conditions in the Niagara Impoundment.
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Hattingh (South Africa), the invited discusser, stressed
the importance of sediments to water quality in reservoirs. He
pointed out that sediments can bind a large number of compounds
including heavy metals and can transport these compounds over long
distances to reservoirs. He referred to studies in South Africa
which showed that about 80 percent of the total phosphorus in
certain streams was bound to the sediments. He drew attention
to the high level of phosphorus, 0.5 mg/£, reported by the authors
as present in the Niagara Impoundment attributable to the large
volume of wastewater discharge. This limited the effectiveness of
the upstream impoundment to store nutrients. In view of the fact
that the impoundment is rather shallow, he inquired as to the
extent of the resuspension of sediment that could result from
mixing by wind action. Randall (U.S.A.) replied that there was mixing by
the wind and that the high phosphorus content and anoxic conditions
in the impoundment during summer were related to the large quality
of wastewater inflow. Randall also stated that releasing effluent
high in nitrate content is a control strategy that can be used in
place of aeration in the reservoir. Arvin (Denmark) inquired as
to the level of nitrate needed. Although specific data were not
available, Randall (U.S.A.) was of the opinion that about 2 mg/£
of nitrate was a reasonable value.
Bernhardt (Federal Republic of Germany) stated that
experience in Germany showed that impoundments used to trap sedi-
ment before principal reservoirs were effective and that Ullman
and Bendorf have developed with success a system of building up-
stream impoundments to retain nutrients. Imhoff (Federal Republic
of Germany) supported these comments. It was generally agreed that
the nature of the sediments and the extent and time of year at which
inert sediments may enter the impoundment and amount of organic and
inorganic phosphorus present, as well as electrode potential values
in sediment, would have to be considered in particular situations.
The adverse effects of the upper impoundment on water quality in
the lower reservoir as reported by Randall (U.S.A.) were likely the
result of the large inflow of sewage effluent.
D. Paper No. 46: "River Basin Planning for Control of
Nitrate Pollution," by C. S. Sinnott
and D. G. Jamieson (United Kingdom)
This paper reported the work of the Thames River Authority
aimed at assessing the impact that water quality in general, and
nitrates in particular, have on management and performance of the
Thames water resource system. The Thames basin supports a population
of approximately 11.5 million and covers an area of about 13,000 km3.
The Authority and its agents provide potable water at a rate of
3.3 xlo6 m3/d. An additional 1.4 xl0^m3/cl is licensed for direct
withdrawal. About 58 percent is met by surface water and 42 percent
taken directly from underground supply.
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A recent European Economic Community (EEC) Directive
on water quality standards establishes the maximum permissible
concentration of NO3-N in potable water at 11.3 mg/£. Nitrate
levels in the Thames River and its tributaries have been slowly
increasing for many years. Of particular concern was the fact
that over the past decade there has been a marked upsurge in the
rate of increase. For example, at the Walton Intake, the main
source of supply for London, the average annual concentration of
nitrate-nitrogen has risen from 4.2 mgjl to 7.7 mg/£ between
1968 and 1979. In addition, seasonal fluctuations commonly
cause short-term concentrations to be 2 or 3 mg/t above the annual
mean.
The combination of increasing nitrate concentrations
and the recent EEC directive is posing a potential problem to the
Thames Water Authority and has given impetus to the development of
a program to formulate a planning methodology and definition of
the optimal development strategy using analytical techniques pre-
viously developed for water quantity. Time-series analysis was
used to relate the total nitrate input with the corresponding flow-
weighted average annual nitrate concentration at the Walton intake.
A model was developed and predictions for different scenarios in-
cluding the factors of population growth rates and farming practices
indicated that for the year 2000 predictions of average annual
nitrate concentrations in the lower Thames ranged from 9.8 mg/t
to 15.5 mg/£.
The planning methodology that has been developed is a
large-scale simulation, and is essentially an extension of the
approach adopted for the quantity aspects of water resources planning.
Five basic component models have been identified: (a) soils sub-
system, (b) aquifer subsystem, (c) channels subsystem, (d) reservoirs
subsystem, and (e) treatment subsystem. The model formulation, para-
meter estimation, and model validation phases have been completed.
Evaluation of alternative strategies to overcome nitrate-related
problems is now underway. It was indicated that in view of the
substantial amounts of money for capital investment and operating
costs to control nitrate concentrations, there is need for a more
realistic basis "for determining a tolerable level of nitrates
in potable water."
Preul (U.S.A.), the invited discusser, stated that in the
United States the maximum contaminant level for nitrates has been
established by the U. S. Environmental Protection Agency (EPA)
at 10 mg-N/£, and this value is based on health effects in infants
and that adults can be exposed to much larger concentrations. Con-
sideration is being given to changes in the value of 10 mg N/£
but nothing definite has been done as yet. Past concern in the
United States has been with well waters but recent data indicate a
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trend of increasing values in river waters. Preul (U.S.A.) emphasized
the need for careful nitrogen balances in a watershed and improve-
ment in fertilization practices.
Vivier (South Africa) stated that if the limit for
nitrate nitrogen was based on health effects in infants, it might
be more cost effective to provide a separate supply of bottled
water for children. In response to his questipn as to how to deal
with denitrification in rivers, Sinnott (United Kingdom) stated
that this was allowed for because the model related the nitrogen
input to the measure of nitrogen at the downstream end.
IV. CRITIQUE OF SESSION
The four papers in this session were concerned with river
and lake water quality. Two papers (Nos. 42 and 44) were directly
related and dealt with questions of forms of phosphorus in sediments
as related to release. These two papers were in substantial agree-
ment that the NaOH extractable orthophosphate (NaOH-O-P) fraction
(i.e., iron and aluminum phosphates) was the main constituent of
sediment phosphorus, and that under anaerobic conditions the bulk
of the release was from iron-bound phosphates.
Both papers confirmed the validity of the phosphorus
fractionation method, developed by Chang and Jackson in the field
of soil science, in providing quantitative information on lake
and stream sediments. Detailed information was provided in both
papers on sediment samples obtained from field locations receiving
substantial loads of phosphorus and other nutrients from sewage
treatment plant effluents. Although the results from the fractiona-
tion techniques provided valuable information op the forms of phos-
phorus present and released to the water column, additional research
to determine the fraction of phosphorus that is biologically available
is warranted.
There was considerable difference of opinion regarding
the effectiveness of an impoundment to trap sediments before the
principal reservoir. Randall (U.S.A.) concluded unless aerobic condi-
tions are maintained in the upstream impoundment, release of nutrients
from previously deposited sediments would and did provide a con-
tinuing source of phosphorus to the outflow during critical summer
months and contributed to water quality degradation in the downstream
reservoir. It was likely that this finding resulted from the large
inflow of sewage effluent to the upstream impoundment and that the
impoundment was acting as a treatment lagoon. Experience in Germany
has been the upstream facilities have had a beneficial effect on
the principal reservoir.
Paper No. 40, which reported the impact of nuclear
power plants on the River Meuse, was indeed a valuable contribution.
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The report, covering five years of investigation, was comprehensive
and detailed. The data analysis provided a sound basis for predic-
tion of the impact of additional nuclear power development on river
water quality.
Paper No. 46 was an excellent presentation of the large-
scale detailed model formulation for comprehensive water resource
planning and management undertaken by the Thames River Authority.
The development of five basic component models and their linkage
provided a means to evaluate alternative strategies to meet require-
ments for nitrate concentrations in water supplies. Although there
has been a large investment in the study, this appears to be justi-
fied in light of the magnitude of expenditures that may be needed
to control nitrate levels. Both the authors and discussers expressed
the need for more definitive evidence regarding health effects of
nitrates in potable water and economic impact to meet prescribed
values.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Although dealing with different pollutants, the large-scale
modeling studies for prediction of impact of pollutants on water
quality in rivers provide excellent examples of the increasing applica-
tion of this approach to water resource planning and management on a
large river basic scale. The Thames River approach might prove of
particular interest in connection with the current requirement by
the EPA to establish water quality criteria for toxic pollutants. In
those locations where toxic pollutants need to be controlled, models
to evaluate the options available will be valuable in making decisions
on a regional basis. As the pollution control problem grows, the
technical, socio-economic, and legal problems become more complex and
systematic planning through the use of simulation modeling and optimi-
zation techniques will be required to implement a rational and
orderly program to approach optimum use of the resource. A detailed
review of the Thames River Authority model should be made.
The papers on phosphorus release provide additional and
confirmatory information on the significance of the sediment as an
internal source and the necessity to carefully evaluate this source
in the nutrient budget of lakes and reservoirs. The analytical
techniques to determine fractional composition of phosphorus forms
appear to be well established, but additional research on evaluation
of fractions that are biologically available is warranted.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: A
Time: 9:00 a.m. to 12:35 p.m.
B. Theme of Session: Concentration Techniques for Viruses
in Water
II. REVIEWER
A. Name: Ronald D. Neufeld
B. Position and Affiliation: Associate Professor of
Civil Engineering
Environmental Engineering
Program
University of Pittsburgh
Pittsburgh, PA 15261
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 48: "Virus Removal by Filtration," by
N. Sriramulu and M. Chaudhuri (India)
This study deals with the utilization of filtration as a
means for virus removal. A "model enterovirus," the MS-2 phage
of E.CoLl, was utilized in this study which was designed to pro-
vide process information for virus removal that may be useful to
the drinking water industry. A column (2.5 cm ID) with 0.5 mm
sand was used for filtration experiments. A groundwater with no
initial turbidity was used in all experimentation. Kaolinite
was added to the groundwater to provide artificial levels of
turbidity; turbidity was removed from the kaolinite-spiked
groundwater sample via coagulation with alum, with and without
use of a polyelectrolyte (Purifloc C-41). Phage concentration
of waters ranged in concentration from 4.6 x 10^ to 7.3 x 10^ PFU/m£.
The sand media was also treated as needed with alum, or alum and
Purifloc C-41. Removal of suspended solids through the column
was found to be first order throughout the 45 cm depth of the sand
column.
Results utilizing virgin sand and water with and without
turbidity showed a 22.6% virus removal in clear water, and a 72.9%
virus removal when influent water with turbidity was utilized. In
this latter experiment, 97.4% of the total turbidity was removed.
The authors concluded that fine turbidity particles act as
carriers of the virus, explaining that when turbidity particles
are removed by the sand filter, the viruses are similarly removed.
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However, due to the fact that the percent removal of virus (72.9%)
was less than the percent turbidity removal (97.4%), it was also
concluded that a small fraction of viruses were not sorbed onto
turbidity particles. In the case of alum-coagulated waters, over-
all virus removal was increased to 98.3%, and the overall virus
removal was increased to 99.8%. Apparently, the process of coagula-
tion aided in overall virus removal due presumably to the sorption
of viruses to coagulated turbidity particles or to aqueous alumina
complexes.
Sand pretreated with either alum or Purifloc increased
virus removal efficiencies. The authors conclude that while
turbidity removal is due to particulate impaction and settling in
deep-bed filters, virus removal in the absence of turbidity is due,
in fact, to electrokinetic phenomena and interaction with sand
surfaces. When viruses are in water with turbidity, viruses tend
to adsorb on to turbidity particles. Since the turbidity particles
become carriers of the viruses, the virus removal mechanism is
thus identical to that of the turbidity particle removal mechanism
in deep-bed filters.
For waters containing zero turbidity, virus removal is
enhanced by pretreating the sand with alum. This will modify
zeta potentials in the neighborhood of the sand particles and
cause electrokinetic capture of virus particles. For normal sur-
face waters where turbidity is present, the best virus removal is
achieved by alum coagulation of turbidity particles followed by
deep-bed filtration with sand also pretreated with alum.
In the assigned discussion, Leong (U.S.A.) noted that few
experimenters are using deep-bed filter processes for virus removal.
He commented that studies such as this would be greatly improved
with more data and incorporation of statistics for a better evalua-
tion of the precision results. Statistical evaluations would lend
a greater credibitility to the premise put forth by the authors that
coagulation and alum-treated sand are useful for virus removal in
deep filtration beds. In addition, the author's allegation that
virus removal was achieved via an electrokinetic phenomena has not
been conclusively demonstrated. Further information is needed to
elucidate the mechanisms involved in virus removal in low- to
zero-turbidity water.
In the floor discussion, Nupen (South Africa) indicated
that the model enteric virus utilized may not, in fact, have been
typical of all enteric viruses. It was their experience that many
rotoviruses and other enteric viruses have zeta potentials close
to zero. Accordingly, while alum-treated sand may removed the MS-2
"model" virus used by the authors, it is questionable whether the
treated sand is similarly effective for all enteric viruses. In
addition, since filter runs were only six hours long, questions
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were raised as to the ability of deep bed filters to remove viruses
over a typdcal 24-hour filter run. Further questions were raised
as to the alum retreatment of the sand after each backwash.
Bernhardt (Federal Republic of Germany) commented that
the reported experiments were valuable first-step approaches towards
process design. In this case, the authors should have sought to
minimize wall effects by utilizing columns with diameters perhaps
as large as 20 to 30 cm. In addition, it is not yet possible to
verify a linkage between turbidity removal and virus removal from
all types of waters. Additional experimentation is required on
a world-wide basis with a variety of surface waters to provide
data illustrating that such a linkage conclusively exists. Thus,
not only are additional experiments necessary to prove the linkage
between turbidity removal and virus removal, but improvements are
necessary in the virus enumeration procedures to assure statistical
validity.
Belfort (U.S.A.) commented that in a real system, with a
distribution of virus sizes, and a distribution of sizes of tur-
bidity particles, the mechanism for capture and attachment is quite
different. With small turbidity particles, the capture efficiency
for viruses may be much greater than when larger particle sizes
are utilized. Accordingly, this study is specific for the one virus,
one flow rate, and one grain size of particle utilized. Extrapolation
of these results to other systems should not be done at this time.
Sproul (U.S.A.) mentioned that previous (unpublished)
dissertation data showed that as sand particles are made smaller,
increased removal efficiencies of viruses are obtained in the bed
filtration. For sand particles of greater than 35 mesh size, minor
virus removals take place. As the sand grain size decreased down
to 72 mesh, increased efficiencies in virus removal were noted.
As the ionic concentration of the water increased, increased virus
removals were noted. In addition, as the concentration of divalent
ions increased (as compared to monovalent ions), virus removal also
increased. It was further noted that much information available in
doctoral dissertations have yet to be utilized by environmental
researchers and practitioners.
B. Paper No. 50: "Enterovirus Concentration Using Auto-
mated Hollow Fiber Ultrafiltration," by
G. Belfort, A. Paluszek and L. Sturman
(U.S.A.)
Data were presented which showed how a small hollow-fiber
ultrafiltration system, as used in hospitals, may be used in an
automated mode for the concentration of viruses from tap and
drinking waters. The automation technique developed by the Amicon
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Corporation (U.S.A.), was further improved under their sponsor-
ship by the authors. Polysulfone membranes of the order of about
250 vim were successfully used to separate viruses from tap water.
No virus was found to exist in the permeate stream. An existing
system was modified with pressure gauges for automated backwashing
use. Poliovirus-2, echovirus-1 and reovirus-1 were utilized in the
study. Initial experimentation found that the viruses were attached
to the membrane and were not recovered when permeate alone was used
for backwashing. The solution concentration of the backwash was
modified by incorporation of pH buffers and glycine in solution to
enhance virus recovery. Poliovirus recoveries were enhanced at
pH values in the range of 9 to 10, while echovirus and reovirus
recovery efficiencies did not appear to be a function of backwash
or pH in the range of 5.0 to 10.0. One disadvantage in using this
technique, as in all virus concentration techniques, was that a
parallel concentration of cytotoxic and trace organic materials may
also occur.
The hollow fiber technique was used with feed concentrations
ranging from 4.3 PFU/mt to 1.1 x 10" PFU/ra£ of enteroviruses with feed
volumes of 3 to 100 I. Concentration factors of 2 to 215 times
were achieved and recoveries ranging from 79% to over 100% were
found. The major advantage of this technique was the automated
capability which was expected to result in a labor savings over
the comnlicated procedures associated with the existing "Tentative
Standard Method" (TSM) for virus recoveries from water.
In his prepared discussion, Sproul (U.S.A.) confirmed the
inherent advantage of using an automated virus concentration re-
covery technique. One disadvantage for the technique, however, is
that recoveries are not complete and viruses tend to stick to the
membrane. This disadvantage becomes apparent if the technique
becomes adopted for regulatory purposes where one needs an assurance
that the virus is recovered clearly from the sample utilized. Un-
less the membrane is removed from the system and changed prior to
each virus determination, no such assurances can be made.
The authors indicated that "cell associated viruses" were
utilized, i.e., were still associated with cell membranes and the
overall particle size of this complex may be on the order of 10 ym,
a size in excess of that expected of discrete viruses in tap or
drinking waters.
Sproul (U.S.A.) raised questions of the engineering
feasibility of a system equipped to sample thousands of liters of
tap water. He pointed out that if a virus standard on the order of
one per thousand liters were, in fact, promulgated, 31 samples,
each of a 1,000-liter size, would be required to be certain that
the standards were met with a 99% confidence level. If an 80%
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confidence level were acceptable, the requirements for sampling
would be reduced to 4,000 liters. In this analysis, it was assumed
that there was a 100% recovery of viruses from each sample, an
achievement which has not as yet been reached by any concentration
technique to date. In addition, a technological limitation in
concentrating large sample volumes would be the limitations imposed
by small levels of turbidity, organic substances and cytotoxic
substances.
In response, Belfort (U.S.A.) indicated that disinfection of
membranes between each run can be readily achieved via the use of
diluted sodium hydroxide on the polysulfone membranes. The problem
of sorption of viruses on the polysulfone membrane is an inherent
difficulty with the technique. Research is under way to examine
alternative hydrophillic membranes, such as regenerated cellulose
acetate membranes and polyamide membranes, as a compromise between
the hydrophobic polysulfone membrane and the hydrophillic membranes
currently available in the marketplace.
Nupen (South Africa) routinely concentrates water for
virus evaluations by factors of about 100. The requirements of
their experimental procedures are to establish a final volume of
approximately 90 m£, and any device that could provide such small
final volumes with increased concentration factors over one
hundred times are welcome. A second point raised was the need to
be absolutely sure that if viruses are found in a sample, they were
derived from the original water sample tested. Because of this
requirement, the South African practice is to carefully sterilize
the total apparatus with great care. Nupen (South Africa) noted that
for an automated system to be practical, not only must the mem-
brane be sterilized after each run, but also peripheral pumps,
tubes, and valves must similarly be sterilized.
C. Paper No. 52: "A Comparative Study of Methods for
Concentration of Human Enteroviruses,"
by M. Martins, E. Marques and
L. Soares (Brazil)
Martins (Brazil) reported on a study to determine suitable
laboratory techniques for the isolation of viruses in sewage
samples from Sao Paulo, Brazil. The techniques utilized
were: adsorption on aluminum hydroxide floe, precipitation by
aluminum sulfate, adsorption to and elution from membrane filters
followed by organic flocculation, direct organic flocculation as
a single-step concentration method, and electropositive cartridge
filter (AMF Cuno filter). The results indicated that the greatest
number of recovered plaque-forming units came from adsorption on
aluminum hydroxide.
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The prepared discussion by Nupen (South Africa) high-
lighted the importance of conducting studies aimed at determining
the type of virus and numbers of types of each virus in sewage
samples. For this study, three polio viruses, five echoviruses,
and four coxsackie viruses were specifically isolated. Nupen
(South Africa) raised questions on the desirability of using the
BS-C-1 cell culture technique for enumeration of both slow-growing
and rapidly-growing enteroviruses. The culture media these
authors used favor the growth of rapidly-growing viruses, such
as of the types reported, and would effectively mask the presence
of any of the slower-growing virus varieties. She further com-
mented that the paper illustrated typical problems associated with
poorly funded viral research in that, to accomplish the goals of
identification of slower-growing viruses, multiple samples as well
as multiple cell-culture techniques should be employed, and for
completeness, an epidemiological study should have been conducted
as to disease patterns before, during and after the viral investi-
gation.
Guttman-Bass (Israel) requested information on overall
virus loss during the filtration and centrifugation phases of
virus concentration. The authors replied that virus recovery
efficiencies at various points within the technique were not part
of this scope of study.
Grabow (South Africa) commented that with the high levels
of E. Coti in the samples, the expected virus concentration should,
in fact, be much higher than shown. He was surprised that no rheo-
viruses were measured. He commented that it was possible that
rheoviruses were not observed due to the nature of the host cell
culture system utilized, and urged that a variety of host cell
systems be utilized in such virology research.
D. Paper No. 54: "A New Large Scale Technic for
Quantitative Recovery of Enteroviruses
by Adsorption on Suspended Glass Powder.
Application to Surface and Drinking
Waters of the Paris Area," by
P. Vilagines, D. Sarrest, C. Danglot,
and R. Vilagines (France)
The purpose of this research was to describe a new and
economical method for the concentration of viruses from drinking
waters and surface waters. The procedure employed was to use
small glass particles with a natural negative electrical charge for
sorption of enteroviruses with a positive charge. The motivation
in conducting this research was to (a) minimize the costs of
filters ordinarily used during standard concentration procedures
and, (b) minimize clogging of filters which operators face when
attempting to concentrate viruses. The procedures are as
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follows: Approximately 2 kg of sterile qlass powder with
diameter size of about 100 to 200 pm are placed in a plastic
cone; water, which is acidified to pH of 3.5, is allowed to flow
in the cone; viruses which are sorbed onto the glass beads are
subsequently removed via an elution using a glycine buffer system
at pH of 11.5; the elutent is inoculated into cell culture systems.
Virus recoveries on the order of 30% to 41% were found with
lower efficiencies coming from river waters and higher efficiencies
from drinking waters. Such recoveries may be suitable and, in fact,
expected due to inherent errors associated with bioassay monitoring
of such living systems.
Roy (U.S.A.) noted that apparatus complexity was, in
fact, on the order of the hollow fiber system [previously reported
by Belfort (U.S.A.)]. He noted that the developers of this tech-
nique did not provide information regarding the influence of tur-
bidity and organic materials on virus recovery rates. In addition,
using the apparatus described, substantial variations occurred
when comparing the results of a single 500-£ sample analyzed for
viruses versus a comparable number of 10-£ samples. It was not
apparent that the 10-£ samples came from the same water source as
did the larger 500-£ sample.
In the floor discussion, Hartemann (France) commented
that percent recoveries are usually evaluated with water samples
that are spiked with a known virus. The percent recoveries of
indigenous viruses in a surface water source may be considerably
less. In addition, he noted that the glass-bead technique is
probably more suitable for sampling of small quantities of sewage
samples because of the advantage of lack of clogging; however, the
conventional filter technique is to be preferred when looking at
high-volume drinking water samples.
Grabow (South Africa) noted that this and other tech-
niques that utilize high pH values for virus elution tend to
destroy certain types of enteroviruses. For example, most Echo
and Rheo-type viruses will be totally destroyed at high pH
values leaving only the polio virus and other hardy virus types
for subsequent cell inoculations. Thus, this technique, as well
as many others, have serious shortcomings in that they cannot
provide information on large numbers of different virus types.
In addition, Belfort (U.S.A.) commented that at pH levels of
about 11.5, portions of the glass beads may be expected to
dissolve thus again leading to questionable results.
IV. CRITIQUE OF SESSION
Research in the field of virus removal appears to be at
an elementary level where reliable measurement techniques are still
to be developed.
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Paper No. 48 dealt with a fundamental evaluation of
removal of viruses in deep-bed filtration systems. Questions
were raised regarding the experimental procedures utilized and
application to large-scale systems. However, it was commented
by many that this was perhaps one of the first approachs asso-
ciated with developing process-type experiments which have appli-
cability to the drinking water industry.
Remaining papers were focused on techniques associated
with concentration of viruses from surface waters, drinking waters
and sewage samples. These papers would have great appeal to
analytical laboratories involved with the routine determination of
viruses in such waters. Apparently, analytical problems and manip-
ulative problems exist with the virus concentration method outlined
in Standard MeAhocU. These papers represent alternatives to the
standard method. It should be noted that concentration methods
are only a portion of the problem and, as pointed out in floor
discussion, serious errors similarly result in the elution method
(which tend to destroy some viruses) and in the cell inoculation
method (which may tend to favor the growth of some viruses over
others).
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
It is clear that waterborne viruses can cause distress
to water consumers. Accordingly, methods for the detection of
virus and for the treatment of viruses in surface waters should be
developed. No epidemiological data, however, have been developed
to quantify the risk of disease from virus contaminated waters, or
to assess the relative risk and importance of the "virus problem"
as compared to other problems (such as PAH's) in drinking water
and wastewater treatment systems.
If regulations are to be developed regarding virus con-
centrations in waters, it is clear that further research and
development in techniques associated with monitoring and treatment
will be necessary. Technological limitations appear to exist in
the area of concentration and recovery of viruses, particularly
those viruses of a less hardy type. While, for example, polio
virus may survive the concentration procedures employed, it is
not clear the polio virus should be used as a "surrogate" for
viruses which commonly are shown to cause disease in water con-
sumers.
Perhaps a more fruitful approach to setting a virus
standard is to set a technological-based standard for the operation
of drinking water facilities. As shown in Paper No. 48, it is
possible to modify off-the-shelf technologies in the drinking water
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industry for the removal of viruses. Further research is required
to resolve questions of time of filter run, sand size and effects
of backwashing. Analytical techniques must be developed to support
this line of research.
If virus standards are to be promulgated in the United
States, consideration should be given to the development of regional
laboratory facilities for cell culture inoculations. A simple but
standardized virus concentration procedure should be developed for
use by operators of local drinking water and wastewater treatment
facilities. Regional laboratories utilizing the more expensive
and sophisticated cell inoculation procedures, may be effectively
employed to provide uniformity and quality control over viral
analysis.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: A
Time: 2:00 to 5:30 p.m.
B. Theme of Session: Disinfection; Surface Water Quality
II. REVIEWER
A. Name: Joseph P. Gould
B. Position and Affiliation: Research Scientist
School of Civil Engineering
Georgia Institute of Technology
Atlanta, GA
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 56: "Ozone as a Sterilising Agent, Its
Advantages and Disadvantages in the
Treatment of Water," by M. Schalekamp
(Switzerland)
The results of laboratory studies and experience garnered
during 30 years of the use of ozone as a disinfectant in Switzerland
were presented. Ozone dosages of 0.5 mg/l or more were sufficient
to totally eliminate all coliform organisms in water. It was found,
however, that ozonated water was subject to a substantial regrowth
of bacteria on standing for three weeks or more. This regrowth
was strongly retarded if 1 mg/l of chlorine was used in addition
to 5 mg/£ of ozone. In this case, regrowth did not begin until
six weeks had passed. The author ascribed this regrowth to the
generation of aldehydes and ketones resulting from the action of
the ozone. He theorized that these carbonyls were being used by the
bacteria as a carbon source thereby stimulating their regrowth.
The correlation between the levels of aldehydes and ketones in
the water and the ozone dosage was clearly documented. The impact
of rapid and slow filtration and activated carbon filtration on
this phenomenon was demonstrated by means of gas chromatography.
Studies on bacterial and viral inactivation by ozone
demonstrated that, in the absence of excessively high levels of
raw water contamination, ozone dosages in excess of 1.0 to
1.5 mg/l would not be necessary. Furthermore, these dosages of
ozone would minimize the generation of aldehydes and ketones.
Ozone was found to contribute substantially to the reduc-
tion of the concentration of such undesirable compounds as phenol
and trichlorophenol and to reduce markedly the generation of
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trihalomethanes on subsequent chlorination of the water, with
50 to 75% reductions being realized. Ozone was also found to
have a beneficial effect on such gross measures of organic
contamination as COD, color and ultraviolet adsorption. Again,
care was urged in minimizing the dosages of ozone due both to
the carbonyl generation phenomenon and the fact the excessive
dosages of ozone were found to have a negative impact on flobu-
lation.
The monitoring of ozone in water and air was discussed.
It was pointed out that ozone is a substantial air pollutant
and that its levels in effluent gases from the ozonation process
should be kept at minimal levels by appropriate treatment tech-
niques. The use of simple dilution techniques for small plants
was described while larger operations were found to be best
served by means of thermal or catalytic processes or by a combined
thermal-catalytic technique. The latter process was found sufficient
to reduce ozone levels in air from more than 3,000 mg/£ to below
detection limits at very modest costs.
van Leeuwen (South Africa) speculated that regrowth after
ozonation might be due to acids generated by oxidation of the aldehydes
produced. He also observed that ozone is not a perfect disin-
fectant since many bacteria such as P. aeAuginota are resistant.
The author responded that, while ozone is indeed not perfect, as
a rule viruses and coliforms are inactivated by ozone and resistant
organisms tend to be relatively harmless strains. Ozone is especially
effective, relative to chlorine, against viruses.
Pretorius (South Africa) asked aboqt the impact of ozone on
flocculation. The author responded that preozonation to levels of
approximately 1.5 mg/l markedly improved flocculation. However, ozona-
tion to 3 to 5 mg/£ tended to reverse the gains realized at the lower
dosages of ozone.
A request by Masschlein for additional data on the
bacterial regrowth curves elicited the response that regermination
will occur only if the ultraviolet absorbance exceeded 0.5 units.
B. Paper No. 58: "The Mechanism of Ozone Inactivation of
Water Borne Viruses," by 0. J. Sproul,
R. M. Pfister, and C. K. Kim (U.S.A.)
The inactivation of the bacteriophage T4 by ozone was
reported in this paper. The results of these studies were compared
with previously reported research on f2 phage. Ozone was found
to reduce T4 phage by seven log-units as measured by the plaque
forming unit (PFU) technique in 120 s at ozone dosages of 0.2 to
0.5 mg/l. The ozone caused a very rapid destruction of the struc-
tural integrity of the phage. The tail sheaths had contracted, DNA
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and base plates were lost and head and DNA destruction had occurred.
Electron microscopy showed conclusively that rapid fragmentation
of released DNA took place with complete fragmentation within
120 seconds.
Some evidence regarding the mechanism of viral inactiva-
tion was presented. Indications were that DNA released from the
T4 phage was rapidly inactivated by ozone. DNA inactivation
occurred at the same rate as that of the phage itself. This con-
trasted with findings obtained with the f2 phage in which nucleic
acids were at least partially inactivated within the capsid sheath.
Indeed, RNA from the f2 phage was inactivated more rapidly within
the capsid sheath than as the naked RNA. In the case of the T4
phage, ozone inactivation occurred by loss of the capsid structure
and release and inactivation of nucleic acid. In addition, ozone
was found to inhibit the attachment of the virus to the host cell.
RNA inactivation was found to proceed more slowly than DNA inactiva-
tion.
A question was asked regarding the nonlinearity of the
disinfection kinetic curves. Sproul (U.S.A.) responded that this non-
linearity was not uncommon and was likely a result of increased
inherent resistance of long-term survivors to the disinfectant.
The author indicated uncertainty concerning the mechanism
by which the RNA was inactivation within the capsid. Grabow (South
Africa) suggested that tight packing of RNA and DNA within the capsid
renders them more sensitive and vulnerable to external disturbances.
He reported that similar results have been obtained in the case of
ammonia inactivation of viral nucleic acids. In essence it seemed
that the capsid was not primarily a protective mechanism.
In response to a question from the chair regarding CIO2
mechanisms, the author indicated that the mechanism of CIO2 inactiva-
tion of virus remains largely unelucidated. Sproul (U.S.A.) indicated,
while a fair amount of information is available on ultraviolet
inactivation of microorganisms and on the mechanisms of H0C1 disin-
fection, few data are available on other disinfectants. Also lacking
is information on the inactivation of higher organisms such as
parasites and cysts.
B. Paper No. 60: "Predicted Changes in Water Quality After
Elimination of Storm Runoff into the Urban
Lakes and Canals of Hamburg," by H. Caspers
(Federal Republic of Germany)
Application of a water quality model to predicton of the
impact of elimination of combined sewer overflow on the quality of
an urban lake was reported. Alster Lake, a small shallow impoundment
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is entirely surrounded by the City of Hamburg. During heavy
rainfall, the impoundment receives substantial overflows from
the combined sewer system. This has led to rapidly increasing
eutrophication in this lake leading to local depletion of dis-
solved oxygen, occasional fish kills and blooms of algae. Methane
and hydrogen sulfide are produced continuously. Construction
projects presently planned or underway are directed toward improve-
ment of the sewer system and consequent reduction of the overflow
of wastewater into the lake. The paper reported on an effort of
predicting the impact of these projects on the quality of Lake
Alster.
Studies in Swedish Lakes have indicated that restoration
of hypertrophic lakes cannot be achieved by termination of nutrient
input alone. Removal of nutrient-rich sediments is also necessary.
A brief analysis of the application of this finding to the Alster
situation indicated that such methods as iron and aluminum precipi-
tation of phosphates, m hita sediment oxidation by nitrate addi-
tion and covering of the sediment layer by fly ash would not be
suitable for treatment of Alster Lake.
A seven-stage chemical water quality index, based on
eight chemical parameters, was used to assess the present status
of Alster Lake and to predict the impact of various strategies
on the saprobic state of the lake. The applicability of the water
quality index chosen was tested by the application of the index
to water quality changes resulting from the termination of sewage
flow into a Hamburg canal. The index successfully paralleled the
changes in quality of the canal. Application of the index to
Alster Lake indicated that a 50% reduction in nutrient flow to
the lake would result in a significant improvement in lake
quality while 90% nutrient removal would produce a year-round balanced
mesosaprobic state in the lake. Annual curves showing changes in
the water quality index for the Eilbek Canal and the predicted
changes in the Alster Lake were given.
The discusser on this paper raised several questions
relative to the use of Water Quality Indices (WQIs) in general and
the particular index presented. He commented that WQIs have been
largely unsatisfactory and expressed difficulty with the use of
single number indices which are oversimplified and lead to numerous
errors. The use of orthophosphate rather than total soluble
phosphorus, which was indicated as being a more reliable measure of
available phosphorus was questioned. He questioned the use of con-
ductivity in this system and asked if fewer than eight parameters
might be used to measure changes in the WQI. He inquired if this WQI,
which was developed for Scottish rivers, could be applied to the
Alster Canal. Finally, he asked what factors tended to keep the pre-
dicted index fairly high, even following removal of 90% of nutrient
transport to the canal. The author responded that he was initially
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skeptical of the value of the WQI, but was impressed by its
ability to describe adequately the current conditions and to
predict changes in real systems. He did agree that the various
parameters will have to be modified in the future to fit specific
situations. He also agreed that total soluble phosphorus would
be preferable to orthophosphate in the index but used the latter
because it was all that was available.
D. Paper No. 62: "Quality and Quantity of Stormwater
Runoff from a Commercial Land-Use
Catchment in Natal, South Africa,"
by D. E. Simpson and P. H. Kemp
(South Africa)
This paper was an examination of the annual import of
nitrogen, phosphorus, COD, BOD and heavy metals by atmospheric
deposition and export of the same by runoff. The study was con-
ducted over a two-year period in an urban catchment of 12 ha.,
of which 9 ha. were classified as impervious. During this
period, atmospheric fallout was collected and rainfall and storm-
water flows measured. Flow-composited stormwater samples were
collected for analysis.
The results were subjected to statistical examination
and numerous conclusions were presented. There was only a weak
relationship between rainfall and atmospheric deposition of
suspended solids and total and soluble phosphorus. There was a
stronger correlation between rainfall and the import of nitrogen,
which was ascribed to transport of ammonia and nitrogen oxides in
rainfall.
Runoff concentrations of most materials measured started
at high levels, decreased rapidly as easily mobilized substances
washed out, increased to a second peak and finally decreased to
low baseline levels. Strong correlations were found for the con-
centrations of suspended phosphorus, nitrogen, COD and all heavy
metals, except zinc, with suspended solids as the independent
variable. Other strong positive correlations were between total
COD and total BOD, suspended phosphorus and suspended nitrogen
and total phosphorus and total nitrogen. Regression analysis for
load-runoff relationships indicated the existence of strong positive
correlations between runoff and total loads of suspended solids,
nitrogen, phosphorus and COD.
With the exception of soluble nitrogen, atmospheric deposi-
tion accounted for well under half (e.g., 15-30%) of materials
transported in runoff. In the case of soluble nitrogen, virtually
all of the stormwater transport could be accounted for by atmospheric
deposition. The stormwater management model (SWMM) of Huber and
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co-workers was applied to data obtained in this study. It was
found that SWMM produced excellent predicted hydrographs but that
failed to predict the transport of pollutants in stormwater.
The discusser endorsed the majority of the findings and
commended the authors on a well-designed study. He suggested
that a study of rural versus urban runoff in this manner would
be of interest. He inquired about the use of only a portion of the
total rainfall in the study and inquired concerning the impact of
dry periods of various lengths. He also suggested that the anomalous
first-flush behavior of phosphorus may have resulted from sorption
of the phosphorus on solids. The author agreed with comments re-
garding the sorption of phosphorus. He also indicated that the
rainfall shortage was due to equipment failure.
Barnwell (U.S.A.) indicated that failure of the stormwater
management model was not a surprise. Similar problems had been en-
countered in the United States and such failures seemed unavoidable in
a model as empirical as this one. He advised the authors of a newer
version of the model which includes atmospheric deposition rates.
The author indicated that they were currently assessing
the new model and expected it to help markedly. He also described
steps taken to modify the older model empirically. This effort
seems to have yielded a substantial improvement in the agreement
of the model with field observations.
IV. CRITIQUE OF SESSION
The paper by Schalekamp (No. 56), while providing experi-
mental research results, was oriented toward practial aspects of the
application of ozone as the primary water disinfectant. The paper
provided a wealth of operational detail and some substantial recommen-
dations in the area of ozonation for water disinfection. Paper
No. 58 also dealt with ozone disinfection but presented results of
sophisticated laboratory research into ozone disinfection mechanisms
with particular reference to viral inactivation. While direct
practical applications of the results of this research are limited,
the contribution of this paper to understanding of the disinfection
mechanism was substantial.
The other papers (Nos. 60 and 62) dealt broadly with
water quality considerations in the normal aquatic environment.
Caspers (Federal Republic of Germany) examined the use of a water
quality index in predicting the impact on a lake of the elimination
of stormwater overflow from combined sewers. The paper was useful
in drawing attention to both the issue and the inadequacies of
existing water quality indices in either quantifying existing water
quality or predicting the impact of changes on quality.
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Simpson and Kemp (South Africa) evaluated the impact of
stormwater runoff and atmospheric fallout on the transport of po-
tentially detrimental materials into surface waters. An im-
pressive feature of the paper was the extensive statistical
analysis performed on the data collected. This analysis enabled
the authors to assess the significance of various interrelation-
ships in the runoff and fallout.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Paper No. 56. The findings of this paper pointed out
the need to continue research into the impact of ozonation on
general water quality. The finding that regrowth of bacteria can
be stimulated by nutrients resulting from ozonation of non-
degradable organic compounds emphasized the types of pitfalls
facing researchers into any of the alternatives to chlorine. The
generation of low molecular weight carbonyl compounds on ozonation
of water-bourne organics also suggested that undesirable products
may arise if such a water is then chlorinated. Research into
such phenomena is necessary.
Paper No. 58. This paper continued investigations into
the mechanism of disinfection. The clear implication of this
paper for water pollution research in the United States is that
the understanding of disinfection processes remains utterly in-
adequate to permit disinfection in the most accurate and economical
manner possible with minimal use of potentially hazardous disin-
fectants.
Paper No. 60. Perhaps the most important indication from
this paper was the need of further developing, testing and refining
comprehensive water quality indices. While the index used did
provide some approximations of the actual behavior of the water
bodies studied, it was obvious that more refinement is needed.
Paper No. 62. This paper demonstrated the need for
continuing research into the importation of pollutants by atmos-
pheric fallout and stormwater runoff to surface waters. In addi-
tion, by documenting the total failure of a sophisticated hydro-
logic model to predict runoff transport of pollutants, a distinct
gap in our modeling methods has been emphasized. Research toward
eliminating this gap is required.
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I. SESSION
A. Day: Monday, March 29, 1982
Hall: B
Time: 11:45 a.m. to 12:30 p.m.; 2:00 to 5:30 p.m.
B. Theme of Session: Biological Waste Treatment, Sludge
Incineration and Rheology
II. REVIEWER
A. Name: William C. Boyle
B. Position and Affiliation: Professor, Civil and
Environmental Engineering
The University of Wisconsin
Madison, WI
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 2: "The Effect of Aeration Basin Configuration
on Activated Sludge Bulking at Low Organic
Loading," by S. E. Lee, B. L. Koopman,
D. Jenkins, and R. F. Lewis (U.S.A.)
Over the past eight to 10 years, a substantial research
effort has been devoted to the evaluation of the influence of
reactor basin configuration and method of feed on activated sludge
bulking control. Continuous-flow laboratory-scale studies were
conducted to evaluate the effect of aeration basin configuration
on low organic loaded systems typical of plants designed to achieve
nitrification. Initially, the authors were unable to achieve a
bulking condition at a range of F/M loadings of 0.05 to 0.25 g
COD removed/g MLVSS using weak domestic wastewater. This weak
wastewater was supplemented by blending with primary sludge to in-
crease the COD concentration to 750 mg/£. Thereafter, bulking was
achievable at low F/M loadings in a completely-mixed reactor
configuration.
Nine reactor configurations were examined during this
study. Compartmentalizing the aeration basins into two, four,
eight and 16 equal-sized reactors did not cure nor prevent filamen-
tous bulking. When the initial compartment size was reduced to 1/74
of the total aeration basin volume, sludge bulking was controlled.
Multiple small basins were unnecessary in this control scheme. Brief
studies were also conducted with two small anoxic compartments (each
1/64 of the total basin volume) preceding a larger completely mixed
basin. This configuration was unsuccessful in achieving stable
bulking control.
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The authors showed that sludge volume index (SVI) could
be related consistently to the organic loading on the initial
compartment as measured by F/M or soluble COD. No consistent re-
lationship occurred between SVI and dispersion number or floe
loading.
The mechanism by which the use of selectors or the
employment of plug-flow aeration basins produces low sludge volume
indices is still unresolved. The authors proposed three possible
hypotheses for the success of these configurations. The first was
that the presence of high levels of materials found in the small
initial reactor may be inhibitory to filamentous organisms. A
second proposal indicated that a selection might take place in
this initial reactor whereby floc-forming organisms grow faster
at higher organic loads than filamentous organisms. Finally,
it was proposed that a selection of floe formers may occur because
they can store and utilize storage products more readily than the
filamentous organisms. The authors further presented data to
illustrate the importance of substrate absorption in the initial
compartment. They demonstrated that SVI decreased as the amount
of substrate removed by absorption, rather than by oxidation,
in the initial compartment increased.
Currently, this technique is being tested at a 7.5 £/min
Phostrip pilot plant at Central Contra Costa Sanitary District
in California. Two 1/74 total aeration basin volume selectors are
achieving bulking control at this facility at a range of F/M
loadings of from 0.2 to 0.9 g COD removed/g MLSS -d.
The formal discussion by Boyle (U.S.A.) pointed out that
this study substantiated earlier work reported for similar loading
conditions but that quantitative differences in achieving positive
results (based on initial compartment loading) was likely due to
differences in wastewater characteristics. He also pointed out
that a good deal of variation existed in the predominant filamen-
tous organisms during this laboratory study. The successful reactor
configurations employed by these authors appeared to prevent or
cure bulking caused by all of these types. He suggested therefore
that the control mechanisms might vary for a variety of reasons.
The authors agreed with the discussion by Boyle (U.S.A.) and
emphasized the fact that waste characteristics play a fundamental
role in the techniques used to control bulking. Based on their
most recent experiences at Richmond, California, the degradable
soluble fraction of the waste material must be absorbed in the
initial compartment. Thus, the influent concentration of soluble
substrate will have a very fundamental role in the design of the
initial contacter unit.
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In the floor discussion, Kroiss (Austria) cited two
examples of the use of reactor configurations to control bulking.
The first, a highly loaded plant for the city of Vienna, was piloted
about eight years ago. Successful bulking control has been achieved
in the full-scale plant for two years through the use of two anoxic
reactors in series each with 1/8 of the entire system volume. These
reactors are followed by three additional aerobic tanks in series,
each with 1/4 of total volume. The other example presented was a
study with an industrial waste plant. He cited substantial dif-
ferences from pilot- to field-scale operation and indicated that
successful bulking control was achieved through the use of an
initial compartment with 1/40 of the total volume followed by a
large completely stirred reactor. He emphasized the importance of
the first compartment in removing up to 50 percent of the oxidizable
substrate. The author acknowledged this work as further evidence
of the importance of waste specificity on the design of the initial
selector. He felt that there is a way to go before we will under-
stand why different configurations give different results.
Roberts (South Africa) suggested that there may be a
relationship between filamentous organisms and denitrifying activity
in activated sludge. He asked whether denitrifiers are predominantly
filamentous or whether filamentous organisms might develop a sym-
biotic relationship with nitrifiers in activated sludge. The author
responded that he had no knowledge as to whether filamentous organisms
denitrify but that he felt that filamentous organisms should not be
too important to the denitrifying process since they make up only
1 to 2 percent of the total microbial population during bulking conditions.
Kerdachi (South Africa) asked how bulking sludge was
quantified and how the sludge volume index (SVI) was measured. It
was his experience that at high mixed liquor concentrations (4000 mg/l
or greater) SVI was meaningless. Finally, he raised questions
regarding the presence of dissolved oxygen and bulking sludges.
The author indicated that SVI was measured using an unstirred
settling test at a constant initial solids concentration of 2.5 g/I.
This test appeared to give results similar to the German diluted-
SVI method. Bulking sludge was quantified as a sludge with a SVI
exceeding 150 rvt/g. High dissolved oxygen concentrations were
maintained (greater than 2.5 mg/£) to prevent filamentous bulking,
but the author agreed that pin-point floe can result at high dis-
solved oxygen concentrations in lightly loaded plants.
Wiechers (South Africa) asked if a critical study has
been initiated to evaluate the mechanisms involved in bulking con-
trol by the use of selectors. He indicated that many bulking
problems and their solutions are site specific and asked if any work
had been done on scale-up of this laboratory work to full-scale
operation. The author indicated that work was now underway at the
University of California-Berkeley using several pure culture isolates
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of filamentous organisms. He felt that it would be some time before
specific mechanisms for control would be delineated. Scale-up at
Central Contra Costa was sheer luck, and at this time no scale-up
work has been done.
B. Paper No. 5: "Obtaining Secondary Treatment with
RBC Underflow Clarifiers," by
I. L. Bogert (U.S.A.)
This paper presented the results of a one-year experi-
mental study at Edgewater, New Jersey, to evaluate the effectiveness
of the installation of rotating biological contactors (RBC) in
modified primary sedimentation tanks to provide secondary treatment.
A single primary tank was divided into two horizontal zones separated
by an intermediate floor. Four RBC units were installed in the
upper zone. High-rate sedimentation preceded the process to remove
grit and floatables. Three loading conditions were evaluated—a low
loading condition to insure an effluent quality better than 30 mg/£
for BOD and suspended solids; an increased load to achieve a 30 mg/£
effluent quality; and a high load condition to stress the system.
The study indicated that the RBC-underflow clarifier con-
cept was an effective secondary treatment process capable of meeting
current United States EPA effluent standards for BOD and suspended
solids. Pretreatment for removal of grit, floatables and screenable
materials was required. The author indicated that organic removal
efficiency was limited by dissolved oxygen concentrations and that
seasonal effects appeared to be minimal.
In formal discussion by Molof (U.S.A.), several questions
were raised regarding the experimental results and interpretation.
No rotational speeds (a parameter of substantial importance in
oxygen transfer in RBC systems) were presented in the paper, and
the type of media surface was not described. The insensitivity
of the system to a temperature difference of about 15°C between summer
and winter was also of some surprise considering the historical
literature on other fixed film systems. The discusser suggested
that the lack of response to this temperature difference could be
due to dissolved oxygen limitations during the high temperature
experiments. The discusser further questioned the value of the
kinetic model presented because soluble BOD data were measured as a
24-hour composite whereas dissolved oxygen values were presented
only during peak-flow periods. Finally, the discusser felt that
response to increased BOD loadings may have been due primarily to
decreased hydraulic residence time (caused by increased hydraulic
loading) rather than organic overloads. The author responded by
indicating that many of the details of this study appear elsewhere
in an EPA report on this investigation. He agreed that dissolved
oxygen might account for the apparent insensitivity of the process to
seasonal temperature changes.
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Seyfried (Federal Republic of Germany) asked if clogging
was a problem at high organic loadings. The author indicated that
there were no problems with clogging.
C. Paper No. 8: "Optimization of Nitrogen Removal in the
Single Sludge Activated Sludge Process,"
by A. C. van Haandel, P. L. Dold and
G.v.R. Marais (South Africa)
Dold (South Africa) outlined considerations which led to the
development of a design procedure for optimal nitrogen removal in
the single-sludge nitrification-denitrification system. The design
procedure was presented as a series of rules to allow rational
selection of process configuration and operational parameters.
The basic concepts governing these rules have been reported pre-
viously by these investigators and were briefly reviewed.
Nitrate profiles in the predenitrification plug-flow
reactor showed two linear phases described by rate constants K]
and K2. Only a single linear phase for nitrate reduction was
observed in the post denitrification reactor (described by K3).
The two-phase nature of denitrification in the predenitrification
reactor was found to arise from the two-substrate nature of the
influent COD in domestic wastewater. In the design procedure, two
conflicting requirements must be met—efficient nitrification must
be insured and maximal denitrification must be achieved. The
requirement for nitrification sets a limit on the anoxic fraction
allowed in the process. The mass of nitrate produced per unit of
COD depends on the influent TKN/COD ratio whereas the amount of
denitrification achieved depends chiefly on the mass of readily
biodegradable influent COD and the anoxic mass fraction. For any
set of wastewater characteristics including influent TKN/COD
ratio, rapidly biodegradable COD fraction, and maximum specific
growth rate of nitrifiers, a set of curves may be developed for
any temperature. These curves may then be used to rationally
select process configurations to optimize nitrogen removal.
In formal discussion, Matsuo (Japan) reported on the
design model and procedure used by his group in Japan for a
Bardenpho-like process called the Inner Recycle Process or Denipac.
Developed in 1971, the process flow sheet is identical to the
Bardenpho system except that methanol or isopropanol is dosed to
the post anoxic reactor. Basic differences in the design model
used by Matsuo (Japan) from those presented by the authors included:
(1) The assumption that the decay rate for nitrifiers in the anoxic
and aerobic zones is negligible; (2) The assumption that the
endogenous respiration rate of heterotrophes in the anoxic zone
is also negligible, and (3) No constraint for the volume fraction
of the anoxic zone. The design procedure, which was briefly outlined,
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was similar to that presented by the authors but included an evalua-
tion of the limitation of oxygen supply in the aerobic reactor. The
use of an aerobic sludge age was also introduced into the design
procedures to replace system sludge age. The discusser also briefly
alluded to problems with setting and optimizing reactor MLSS levels
in this system.
Dold (South Africa) expressed great interest in the parallel,
yet independent, development of similar treatment configurations,
models and design procedures for nitrogen removal. He pointed out
that the addition of easily biodegradable substrate to the post-
denitrification reactor would greatly improve the capacity of that
reactor and that its behavior would be the same as that of the pre-
denitrification reactor. The assumption of negligible endogenous
respiration by nitrifiers would not result in any significant dif-
ferences in design between the two groups since Matsuo (Japan) employed
an aerobic sludge age whereby the Cape Town group employed a total
system sludge age and nitrifier decay. The author cited experimental
evidence, however, that supported the need for the inclusion of a
heterotrophic endogenous respiration constant in the design approach.
Finally, the author felt that the provision for aeration limitations
in the aerobic reactor by Matsuo (Japan) represented a useful extension
of the theory.
In the floor discussion, Roberts (South Africa) remarked
on the substantial differences in the specific qrowth rate constant
for nitrifiers used by Matsuo (Japan) (0.214 d~') versus that often
seen for domestic wastewater (0.65 d-lj and asked if the differences
might be due to measurement errors. Marais (South Africa) responded
that the measurement was very complicated, being obtained by simulation
using experimental data collected in the laboratory by switching the
system from aerobic to anoxic. He indicated that in Cape Town, two
domestic wastewaters give significantly different values of the growth
rate and that he has seen values ranging from 0.1 to 0.7 d~l. Without
knowing what affects this rate, engineers tend to be conservative
selecting a design value.
Wiechers (South Africa) asked what effect the optimization
of nitrogen removal in the single sludge system had on sludge
settleability. Marais (South Africa) replied that initially it was
related to anoxic sludge mass. Now they have found that it is really
a function of hydraulic residence time in the anoxic zone. If this
time is greater than one to 1.5 hours, sludge setteability deteriorates.
The same phenomenon also applied to the Phoredox processes with respect
to the anoxic zones, but for some reason setteability is unaffected
by the residence time in the anaerobic zone.
Beekman (South Africa) asked whether any studies had been
done with settled wastewater, in addition to those presented for
unsettled wastewater. Ekama (South Africa) replied that process
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calculation can be used for both settled and unsettled wastewater
and that laboratory and pilot-scale plants have been operated with
both types of wastewater. Since primary clarification removes more
COD than TKN, the TKN/COD ratios for unsettled wastewater are higher,
and it is,therefore,more difficult to remove all of the nitrogen
without addition of methanol in these systems.
Meiring (South Africa) asked the authors to describe the
basic differences between Phoredox and Bardenpho processes. Dia-
grams were presented to illustrate the two flowsheets. The Phoredox
process is designed for simultaneous biological nitrogen and phos-
phorus removal. The Bardenpho process is designed for biological
nitrogen removal only.
Jenkins (U.S.A.) asked whether the organisms causing
bulking were identified. Marais (South Africa) indicated that
bacteriologists had identified the organism most often seen as
as a blue-green algae. He described the organism as a thin fila-
ment which developed nodules just prior to death. Jenkins (U.S.A.)
indicated that in studies with the Phostrip process in California,
no bulking was observed with solid retention times in the anaerobic
reactor up to 10 hours, which corroborated earlier comments by
Marais (South Africa). Jenkins (U.S.A.) asked whether the model was
supported by any data. Marais (South Africa) indicated that the
paper presenting experimental data was published in (alcuteA Rte&asiclri
in 1981. Data collected over seven to eight years were used to
develop the model presented in this paper.
Pretorious (South Africa) was interested in how often the
laboratory vessels were cleaned of wall growth that might catalyze
biochemical reactions. Marais (South Africa) indicated that reactors
were kept meticulously clean. Once per week sludge was removed
and the reactors were thoroughly cleaned. He indicated that
much of the bad data published was due to wall effects in the
system.
Barnard (South Africa) emphasized the importance of
scale-up from laboratory to full-scale plants. He indicated
that the aeration system can have an important influence on pro-
cess operation. He cited a case in Copenhagen where several
surface aerators were turned off. This created anoxic zones
which resulted in filamentous bulking. He felt that diffused air
systems were more readily controllable and that gas flows could
be turned down to avoid oxygen entrainment in the post denitrifi-
cation tank without creating anoxic zones in the aeration tank.
Marais indicated that direct scale-up was possible if one can
avoid the effect of wall growth.
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D. Paper No. 11: "Fate of Heavy Metals and Potential
for Clinker Formation During Pilot
Scale Incineration of Municipal Sludge,"
by H. W. Campbell, P. J. Crescuolo and
T. R. Bridle (Canada)
Bridle (Canada) presented data on a pilot study used to
develop a data base on the fate of heavy metals contained in
municipal sludge and the potential for clinker formation when
incinerating this sludge. A factorial design was developed
examining the influence of the independent variables--!'ncinerator
temperature, throughput rates of sludge and center shaft speed-
on the fate of selected metals, organic carbon and clinker for-
mation. An Envirotech BSP pilot multiple-hearth incinerator with
six 0.76-m hearths was used for the study.
The author reported that phosphorus, chromium, nickel,
copper, lead and zinc were conservative and remained in the ash.
Cadmium volatilization was a function of temperature ranging from
25% at 760°C to 56% at 928°C, but most of it was recovered in the
scrubber water. About 26% of the arsenic was classified to the
scrubber water but not to the atmosphere. By inference, greater
than 99% of the mercury was classified to the gas stream but
lack of samples from the scrubber precluded conclusions regarding
the amount reaching the atmosphere.
Clinker formation was found to occur only at the highest
temperature (928°C) with long residence times (e.g., lowest rates
of input and center shaft speed). This clinker formation could be
eliminated at high temperatures by operating at high sludge through-
puts. Carbon destruction was essentially complete under all
experimental conditions.
The formal discusser, Gerber (South Africa), indicated
that, among other reasons, cost considerations discouraged incinera-
tion of municipal sludges in South Africa. He asked about Canadian
costs. Bridle (Canada) responded that sludge incineration was prac-
ticed in Canada where there were heavy urban densities. Recent
cost estimates made for Burlington, Ontario, indicated a value of
$200/ton (Canadian).
Gerber (South Africa) asked if the author could account
for differences found between this work and work done in the United
States with respect to cadmium volatilization. United States study
showed that cadmium was classified with the ash. The authors re-
plied that they had no idea why they were not able to account for
the cadmium. They speculated that differences between this work
and that done in the United States might be due to different in-
cineration systems since the study in the United States was per-
formed with a fluidized-bed incinerator and with completely dif-
ferent ash removal techniques.
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Gerber (South Africa) asked about the quality of the
scrubber water and its influence on treatment plant operation. The
authors indicated that scrubber water was used in a once-through
mode for both pilot studies and at Hamilton. Cadmium concentrations
of 20 yg/x, were measured in this scrubber water and arsenic was
found to be 22 pg/£.
Finally, Gerber (South Africa) asked about scale-up of
pilot plant studies to full-scale operation with respect to clinker
formation. The authors indicated that they did not know how to do
this but felt that manufacturers did have some idea about how
to go from pilot- to full-scale operation. They indicated that
the objectives of their study were to obtain general indications
of performance, not to provide quantitative numbers for scale-up.
In the floor discussion, Ruffer (Federal Republic of
Germany) pointed out that heavy metals could be fixed in the ash
so that resolution is not possible once the ash is disposed. This
method, published over 20 years ago, fixes the metals by a melting
process forming a clinker. The author concurred with this.
Kugel (Federal Republic of Germany) indicated that problems
at a wastewater treatment plant in West Germany were encountered
when incineration of a sludge high in reduced chromium (Cr+3) was
oxidized to Cr+6 during incineration. The author indicated that
no measurements were made of valence state in this study but that
another study done in Burlington, Ontario, showed that chromium
in the incinerator ash was immobile.
Richardson (South Africa) asked what the nature of the
sludge was and how it was dewatered. He also asked if there were
emission standards in Canada for incinerator discharges. The author
indicated that the test sludge was a mixture of municipal primary
plus waste-activated sludges. He indicated that the primary sludge
was dewatered on coil filters and the waste-activated sludge was
thickened by dissolved air flotation. There are no emission
standards for metals in Ontario province for municipal incinerators,
only a particulate standard.
E. Paper No. 14: "The Use of Rheology for Sludge
Characterization," by H. W. Campbell
and P. J. Crescuolo (Canada)
Experimental work was conducted at the Wastewater Technology
Center in Burlington, Canada, to evaluate the use of rheology as a
process control parameter for sludge conditioning. This work was
initiated after the authors found that an apparent relationship
existed between a peak in the shear stress-shear rate curve for a
conditioned sludge and the polymer dose required to give efficient
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dewatering in pilot-scale trials. Their goal was to develop a
standardized procedure for testing sludges in a commercial visco-
meter and to determine the effect of machine variables on the
resulting sludge rheograms. Finally, he presented preliminary
results on the interpretation of these rheograms. This was a
report on preliminary results of this method. The author was
enthusiastic about the potential of this method but was clearly
cautious about its use without further study and evaluation.
In formal discussion, Marchandise (France) raised a
number of questions regarding the usefulness of the method, the
wide range of variability in the data and the uncertainties associated
with the theory. His first remarks raised the question as to
whether rheology offers a benefit for process control that is better
than parameters currently used, such as specific resistance and
capillary suction time (CST). The author indicated that he was not
sure that rheology was a better method. However, he indicated
that it has been used by industry as an on-line control parameter.
If one can understand what is happening, he felt the use of the
viscometer as an on-line control device would be superior to other
methods now being used.
Marchandise (France) inquired about discrepancies
that existed between rheograms in several of the figures presented.
The author indicated that the rheograms were obtained from different
sludges. He also indicated that the differences seen in some of
the curves were due to the shearing of the flocculated sludge prior
to being introduced into the viscometer. He also indicated that
he did not feel it would be possible with this method to scale-up
to full-scale conditioning.
The discusser was also disturbed by the fact that some
sludges did not demonstrate characteristic peaks and asked if this
was widespread. The author again indicated that the curves
represented a wide range of solids concentration and physical
characteristics which will contribute to the character of the
rheogram.
Marchandise (France) questioned the technique used to
relate rheology to sludge particle size since the sludges were
diluted and an electrolyte was introduced. The author agreed
with this and indicated that he felt that the relative mean-particle
sizes were probably reasonable but he did not know about the
absolute sizes.
In floor discussion, Moller (Federal Republic of Germany)
asked if parallel tests have been performed between viscometer and
CST and, if so, did they produce parallel results. The author indi-
cated that parallel tests were performed and when a peak was detected
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on the rheogram, the CST values were in the range of 10 to 20 s.
This correlated well with studies done at their laboratories with
conditioned sludges (i.e., super-flocculated sludges normally
yielded CST values of 10 to 15 s). Moller also expressed concern
over the effect of conditioning on particle size and the influence
of shear in the viscometer on the data obtained. The author indi-
cated that as the polymer dose increased, more breakdown would
result but the resulting particle sizes were still greater than
those with the next highest polymer dosage. He agreed that more
work still needs to be done on this.
Rose-Innes (South Africa) indicated that he has been
doing work with waste-activated sludges (concentrations up to 6%)
using a viscometer to evaluate sludge flow in pipelines. He also
found the characteristic peaks described by the author at high
sludge concentrations. He indicated that depending on the rotor
head used, one could find the sludge moving from laminar to turbu-
lent flow which would be of concern. He also indicated that for
non-Newtonian fluids such as the sludges studied by the author,
shear rate was not proportional to turn rate and that variable
calibration would have to be incorporated.
Seyfried (Federal Republic of Germany) asked what practical
purpose was served by this study. The author emphasized the impor-
tance of developing a control method with rapid utility. He felt
this method would provide operators with quick information on changes
in sludge characteristics.
Dick (U.S.A.) indicated that he felt the peak in flow
curves were unique in rheology studies and asked whether the author
knew why it occurred. The author indicated that he was unsure but
it may relate to particle size or particle size distribution (or
both). It might also be due to the realignment of mass conglomerates
in the viscometer.
IV. CRITIQUE OF SESSION
The papers dealing with filamentous bulking and nitrogen
removal were well received and enthusiastically discussed. There
has always been a great deal of interest in activated sludge bulking
control and Paper No. 2 stimulated a great deal of interest in the
mechanisms of control affected by compartmentalization. It appears
that there is general concurrence among researchers that basin
configuration plays a very significant role in effective and reliable
control of filamentous bulking. The major questions now deal with
how to rationally design these initial contact basins, whether there
are decided advantages to anaerobic versus aerobic contactors and,
of course, the mechanisms for control.
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The paper on nitrogen removal (Paper No. 8) was
one of a series of excellent papers produced by the University of
Cape Town. These investigators are clearly among the leaders in
this field and the discussion was lively and informative. It
was very interesting to note the interest expressed by the Cape
Town group regarding the parallel work being done in Japan which was
previously unknown to them. A number of useful questions were also
raised regarding design constraints, bulking problems and scale-up.
The discussion on the use of RBCs in primary clarifiers
received little attention by the delegates, perhaps because it was
a summary of a more detailed report that was unavailable to most.
Most concern centered around the data base and its interpretation.
The paper on incineration of sludge received some discussion, pri-
marily by those delegates outside of South Africa where incineration
of sludge is not normally practiced. The question of heavy metal
recycle in the environment prompted several interesting discussions.
Finally, the proposed method of the use of viscometers for controlling
sludge conditioning received a mixed response. Considerable doubt
was raised by several discussers as to the value of such an in-line
control device, at least until more is known about rheograms.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The subject of activated sludge bulking continues to be
one of the high priorities in operation research in the United
States. Considerable progress has been made over the past eight to
10 years in verifying that reactor configuration is an important
factor in controlling filamentous bulking. Since a greater emphasis
is being placed on nitrification in this country, the lower loaded
plants (and, therefore, potentially a greater likelihood of fila-
mentous bulking) will be a focal point for these control strategies
in the near future.
The removal of nitrogen in wastewater will continue to
receive substantial attention in the United States. The contribu-
tions of South Africa to a better understanding of biological nitro-
gen (and phosphorus) removal, and the design and control of such
processes are of great value to the United States research program.
The paper presented on this topic (as well as several others) pro-
vides additional useful information to our current data base for
design and operation of these processes.
The retrofitting of existing overloaded plants in the
United States is becoming a national effort. The contribution of
the RBC to the upgrading of plants may be significant. The paper
presented in this section may stimulate further research in the
application of RBCs to certain retrofit situations.
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I. SESSION
A. Day: Tuesday, March 30, 1982
Hall: B
Time: 8:30 a.m. to 12:05 p.m.
B. Theme of Session: Desalination and Filtration
II. REVIEWER
A. Name: Edward S. K. Chian
B. Position and Affiliation: Professor of Environmental
Engineering
Georgia Institute of Technology
Atlanta, GA
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 17: "Slow Sand Filtration for Cercarial Control
in North Cameroon Village Water Supply,"
by K. Kawata (U.S.A.)
The control of cercariae of human schistosomes in the water
supply of North Cameroon was studied with the use of locally available
and acceptable slow sand filters. Based on a literature survey, no
consideration was given to sand characteristics or realistic operating
parameters for the removal of "old" cercariae with slow sand filters.
The study was conducted with Sclvuto.&oma maMoni cercariae within one
to two hours after shedding. The parameters under study involved
filter sands having three effective sizes of various uniformity co-
efficients, three filtration rates and two depths of sand bed. In
the light of these test results, design parameters were selected
with effective size of the filter sand to be 0.3 mm or less with a
uniformity coefficient of 2.0 or less. The initial bed depth was
selected to be 1.2 m. The bed may be scraped down in the cleaning
process with the caveat that the sand depth must not drop below
0.6 m. The designed filtration rate was 0.12 m/h or less. Good
practice required that filters be thoroughly conditioned before being
placed on line and at no time should the sand be allowed to dry out.
When beds are allowed to dry, they can shrink and pull away from
walls which can create pathways for cercariae to pass through.
Williams (South Africa) indicated that the subject
is of particular interest in South Africa. The National
Institute for Water Research in Pretoria is presently commencing a
project to investigate appropriate design criteria for slow sand
filters to be used under South African conditions. The author has
shown that cercariae can be effectively removed by slow sand filters
based on the design criteria included in a WHO booklet published in
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1974. This provides added advantage in addition to turbidity and
organic pollutant removal. However, there are two practical points
associated with operation of slow sand filter for cercariae removal.
First, in order to provide effective cercariae control for a com-
munity, an appropriate supply of filtered water is needed so that
the local people will use this supply of water in preference to the
traditional contaminated water supply. Second, when the slow sand
filter is to be cleaned, the Schmmtzd&ckz accumulated at the sur-
face should be scraped off and the spent sand should be allowed to
stand for two days prior to disposal to safeguard workers from the
cercariae-contaminated sands. Two questions were raised. First,
what would be the role of the Sckmitfzde.c.ke. in the removal of cer-
cariae? Second, the experimental results were based on six to ten
runs. The slow sand filters are normally operated for only one to
two months between cleaning. Is there cercariae breakthrough during
a longer filter run?
The author replied that the peA cap+Xa income in the area
is $30 (U.S.A.) and a distribution system or even a pumping station
is not economically practical. The goal for the local government
is not to improve the health of the people but to see that, whatever
is done, the health condition would not be any worse than it is now.
Therefore, they are quite realistic about what can be done with their
water supply system. As to the question of the role the Schmutzde.cke.
played in the removal of cercariae, I would say that the removal
efficiency will increase as the Schmu£zde.cke. is being built up. A
bacterial buildup would also tend to enhance cercariae removal, as
shown in a review paper prepared by the author for WHO. As the
Schmmtzde.ckz is slowly building up, an improved removal of cercariae
is expected.
Pepkie (Canada) inquired about the wall effect of using a
15-cm diameter column slow sand filter. Based on literature, the wall
effect can be eliminated by using 2.5-cm diameter sand column coated
with sand adhered on the wall. The author was not concerned with
the wall effect with the use of a 15-cm diameter sand column.
VanVuuren (South Africa) was concerned with the use of
slow sand filters for treating bacterially contaminated water for
boiler water. He asked if the slow sand filter could be used to
partially disinfect contaminated ground water. The author pointed
out that in Stockholm the slow sand filter is used following the
rapid sand filter for polishing purposes and produces an excellent
quality water. Therefore, the slow sand filter can be used for a
number of applications including partial disinfection.
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B. Paper No. 19: "Characterization of Fouling Potential
for Pressure-Driven Membrane Processes:
A New Simulated Flow Cell," by R. H. Reed
and G. Belfort (U.S.A.)
The paper described the development and testing of a new
apparatus, simulated flow cell (SFC), for the characterization of
fouling potential of pressure-driven membrane processes. This
apparatus takes into consideration the tangential flow across a
membrane surface in order to accurately predict how feed water
foulants behave in a flow field existing in the operation of an
actual reverse osmosis system. The SFC was tested using irradiated
polycarbonate membranes supplied by Nuclepore along with the use of
polystyrene latex spheres (PSL) as synthetic particulate foulants
and also using actual water and wastewater as natural foulants.
The parameters under study included membranes of various pore dia-
meters tested over a wide range of flow conditions, expressed in
terms of Reynolds numbers. In addition, the newly developed dynamic
SFC was evaluated along with the conventional static non-flow cell
(NFC) so that comparisons of plugging factor after various periods
of operation can be made with both systems. When using the 0.1 pm
Nuclepore membrane, all tests in the SFC for axial velocity larger
than 1800 cm/s showed significantly lower plugging factors. For
axial velocities smaller than 1117 cm/s, SFC tests showed no dif-
ference in plugging factors as compared to the NFC tests. The
author concluded that the results suggested that the newly developed
SFC can be used to more accurately predict fouling characteristics
of an actual reverse osmosis (R0) membrane system.
The formal discusser, Chian (U.S.A.), commented that the
definitions of "non-flow" and "simulated-flow" were confusing.
There is actually transmembrane flow occurring in the so-called
non-flow cell and it was suggested that the term "non-simulated
flow" be used in lieu of "non-flow." Also, the term "axial flow"
as used by the authors to indicate flow sweeping over the circular
membrane surface is inappropriate. A more appropriate term would be
either "bulk-flow" or "radial-flow." In addition to editorial
comments, the discusser believed that membrane fouling involved
plugging by either physical deposition of colloidal particles or
chemical interaction of the colloidal materials with the membrane
surface or both. The former can be reduced by hydrodynamic shearing.
The advantage of the newly developed SFC lies in its ability to
reduce greatly the physical deposition that occurs in a real mem-
brane system. The conventional NFC test overestimated the fouling
characteristics of a membrane since it was unable to differentiate
the pure physical deposition from the so-called chemical interaction
of the colloidal materials with the membrane surface.
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The author replied that most of the comments were additive
and accepted them in the good intentions that were given. However,
the author did not believe that attachment mechanisms and transport
mechanisms were important. In fact, he has a whole research group
working on the dynamics of the particles on the membrane surfaces
which is, in fact, the first step of what is called the two-step
process; namely, the particles have to first move to the site of
attachment and then become attached there. It is very analogous
to the flocculation, coagulation and filtration, i.e., the particles
have to get to the membrane site. One can go through a highly in-
tensive mathematical analysis to predict the dynamics of the trans-
port process. The trajectory can be predicted and calculated very
accurately. As far as the comments on the attachment mechanisms
and the interaction forces, they can vary similar to the effect of
pH, shearing lift and ionic strength on the stabilization and de-
stabilization on the colloids. In fact, a higher flux was observed
in the presence of salt in the solution which results in building
up a concentration polarization layer on the membrane surface. This
is contrary to what would often be predicted for a lower flux.
Evidently, destabi1ization of colloidal matter in the presence of
a higher ionic strength appears to play the role of resulting in a
lower hydraulic resistance packing layer on the membrane surface.
As to data in Table 4, absolute Reynolds numbers change
with the distance away from the center of a membrane. A particular
point was selected for the computation of the Reynolds number. The
relative Reynolds numbers, which define the various flow regimes
such as laminar, transition and turbulent, were the concepts of
interest.
Botha (South Africa) asked if any correlation had been made
between values obtained from SFC testing runs to that of fouling
with an actual RO system. He indicated that there was no correla-
tion between membrane fouling with the data obtained from the con-
ventional NFC testing runs. The author considered this to be a most
important question. His answer was that he did not have the re-
sources for making such correlations. However, he was in the pro-
cess of finalizing negotiation with a large French membrane company
to set up a cooperative program to run such correlation experiments.
Also, Mutachen (U.S.A.) of the University of Southern California
has a copy of his cell design to check out with the treatment of
agriculture runoff with the RO system.
DuVediell (South Africa) commented that the Nuclepore filters
used in the SFC were expensive. Are they actually indispensable
as it was stated in the paper? Also, he questioned the pressure
applied in the SFC (30 psi) whereas an actual reverse osmosis
operation is operated at a pressure of 400 psi and higher. What
are the pressure effects on the cake deposited on the membrane?
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The author replied that due to the competition from
Germany the prices of the Nuclepore membrane are expected to fall.
Also, the membrane can be re-used if proper care is taken not to
tear it during the cleaning process. However, if one compares the
costs of operating a RO system with that of the Nuclepore membrane
employed in the SFC tests, the latter are insignificant. The author
agreed that he had not simulated the pressure applied in the actual
RO system since the SFC was designed as a quick, simple and inex-
pensive testing system. This indeed is the limitation of the system.
Hendry (SA) commented that conventional plugging tests
were intended to be used as a crude measurement of presence of
colloids, and should not be used to correlate fouling potential of
a water on an actual RO membrane. He was trying to develop measure-
ments of size distributions of colloidal particles in order to corre-
late RO membrane fouling potential.
C. Paper No. 21: "Desalination by Continuous Ion Exchange
Based on Thermally Regenerable Magnetic
Microresins," by B. A. Bolto and
E. A. Swinton (Australia)
The paper described the unique hydrodynamic and kinetic
properties of "Sirotherm," thermally regenerable desalting resins
made in the form of magnetic microbeads, and the development and
testing of continuous contacting systems which exploited these
properties. This process was designed to partially desalt water
and wastewater containing 500 to 2000 mg/I of total dissolved solids
on a large scale. It consumes no chemicals; only a small amount
of low-grade heat is needed for regeneration. Typical salt re-
moval of 80% was obtained. The advantage of using the magnetic ion
exchange resins was their ability of attaining a high reaction
rate and clumping together for better separation. A novel multi-
stage countercurrent contactor utilizing the principles of distilla-
tion and solvent extraction was evaluated on laboratory and pilot-
plant scales. This process is truly continuous as compared to the
conventional ion-exchange resin system and is simple and economic
to operate without requirement of preclarification of raw water.
However, the process suffered from a few limitations; namely, no
simultaneous removal of divalent and monovalent ions, and sensitivity
to oxidation and organic compounds. These drawbacks can be corrected
by pretreatment of raw water with strong ion-exchange resins for
softening, addition of sodium sulfite for deoxygenation and the use
of organic traps.
Carr (South Africa) initiated the discussion
by presenting an elaborate analysis of the relative advantages and
disadvantages of desalination using the Sirotherm process, SP;
continuous countercurrent ion exchange, CCIX (presented by Hendry
in Paper No. 23); and reverse osmosis, R0. The parameters
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concerned involved pretreatment requirements, product water recovery,
costs of water produced, energy requirements, service life, simplicity
of operation and commercial availability. He summarized that CCIX
has excellent service life and requiras literally no pretreatment,
whereas RO is more energy efficient and simpler to operate. Both
processes are commercially available, in conclusion he stated that,
for the removal of salinity from water, RO is the preferred process,
whereas for removal of salinity from wastewater, CCIX and perhaps
SP are preferable. The discusser invited comments from the author
on the SP and from the audience on the RO process. Also, he asked
the author to elaborate on the difficulties encountered during the
development of the non-continuous and the continuous operations of
the Sirotherm process.
The author replied that up to 85% water recovery was
attainable. The life of the resin was estimated at five years for
a small plant and longer for a larger plant. The plant was indeed
simple to operate. The commercial availability of the SP plant
and the resins depends upon the success of the demonstration plant.
The problems on pretreatment have been resolved satisfactorily by
using a conventional cation-softening process and by using inex-
pensive sodium sulfite to control oxygen. As to the difficulties
encountered with the non-continuous plant, the cyclic process posed
problems in keeping oxygen out and pH control was difficult.
Economically, SP is not in competition with RO for small plants,
but for a larger plant, a single plant treating 20 to 50 million
liters a day is possible and would be more economical. An RO plant
would require thousands of modules for a plant of equivalent size.
Botha (South Africa) questioned the vulnerability of the
resin to oxygen during periods of shutdown, interference by monova-
lent chloride and divalent sulfate in water, and the lack of price
information.
The author replied that the oxidation of resins was a slow
process, the loss of only 1% of the resin occurred in a few hours.
There were no problems with mono- and divalent anions, only the
cations were of concern due to the chelation on the carboxylic
group on the resin. The cost information SP will be evaluated in
parallel with an electrodialysis (ED) process. Currently, the com-
pany is not ready to market the process. A more comprehensive cost
figure will be available later based on large-scale plant studies.
Hendry (South Africa) asked if water recovery was related to
the heat balance inthe cooling system. He also suggested it was
better to use NaCl softening. The author replied that water recovery
was limited by the reflux system in the still. The yield is based
on the difference between the two equilibrium curves on the Thiele
diagram. Operation at 95°C appeared to be an upper limit. The
softening process should be designed on an individual basis.
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Handle (South Africa) asked for elaboration on the
simultaneous removal of mono- and divalent ions. The author
said that the simultaneous removal of mono- and divalent ions
with SP was not economical. The conventional cationic exchange
resin was about the cheapest means of removing calcium and magnesium.
D. Paper No. 23: "Continuous Countercurrent Ion Exchange for
Desalination and Tertiary Treatment of
Effluents and Other Brackish Waters," by
B. A. Hendry (South Africa)
The paper described the development of a continuous counter-
current ion exchange (CCIX) process for desalination of mineralized
effluents and brackish water. The process utilized macroporous resins
in a strong cation/weak anion sequence. The use of a weak anion resin
had an added advantage of removing organic matter from the wastewater
effluents which resulted in 70% reduction of the humus-like COD
materials along with color and odor removal. During a period of two
years of continuous operation without pretreatment, no significant
fouling or loss of resin capacity was observed. Sulfuric acid was
used for the regeneration of the strong cation resin whereas lime
was used for regeneration of the weak anion resin. Water recovery
was improved from 80% to 90% by using a new technique involving a
five-column system with reuse of spent regenerants. Based on a
careful cost estimate, the unit costs of water were 30 to 40 cents
(U.S.A.)/m3 for removal of 500 mg/£ of TDS.
The prepared discusser, Priestley (Australia), pointed
out that although reverse osmosis is the most fashionable means of
desalting brackish water, the in-depth exploration by the author
of the use of the old-fashioned, ion-exchange resins was encouraqinq.
CCIX as developed by the author removed not only salts but also
ammonia, nitrate and organic matter. The use of an innovative re-
cycle of excess acid allowed stoichiometric use of sulfuric acid
for regenerating the strong cation resin, whereas the use of a
low-cost lime for regenerating the weak anion resin provided added
economic advantage to the CCIX process. In order to prevent pre-
cipitation of calcium from occurring, a fluidized bed would be
desirable. However, most of the anion resins have a density close
to that of unity. The use of a heavier anion resin by the author
enhanced the fluidized bed process. The discusser encouraged the
author to collaborate with researchers working on the heavier mag-
netic resins. Whereas it was relatively easy for an engineer to
design a two-component system, it was virtually impossible to deal
with a multicomponent system which was even more complicated with
calcium sulfate precipitation. The author's effort in conducting
a matrix study to explore the real situation was certainly encouraging.
The discusser asked whether the economics could be improved further
with the use of two equivalents of acids per cation. He also in-
quired whether the kinetics of the reactions with the resins were
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studied and about the availability of the resins. He requested
the author's views on the advantages and disadvantages of using
supersaturated calcium sulfate. Was it better to encourage pre-
cipitation within the resin columns or to learn how to handle the
slurry instead of preventing scale from occurring?
In reply, the author evaluated the use of heavier anion
results in a bench-scale study for the design of a larger fluidiza-
tion column. He would like to look into the use of the higher
density syndrix resin or the magnetic resins as described by
Swinton in a previous presentation. In the distillation field,
there were techniques available for the design of multicomponent
systems. It really depended upon how clever one could be in
applying them to the CCIX process and, so far, he could not find
a way of doing it. A limited amount of theoretical work was in
progress on the development of an unsteady-state mode for ion
exchange. Hopefully, the techniques yielded could be applied to
calculate the multicomponent system. The economics of acid equiva-
lent was difficult to evaluate with available data. The half
reaction times on strong cation resin were very short, i.e.,
1-2 minutes, while the half reaction time for anion resin was long,
approximately 20 minutes. On the supersaturation of calcium sulfate,
it would be far better to get the liquid destabilized in the column
rather than to carry it through the column as a supersaturated
solution and trying to get it out afterward. By seeding gypsum
in the bottom of the column, a 20% improvement in calcium removal
was obtained.
Botha (South Africa) asked, "if the TDS were up by 500 mg/I,
would the costs increase by 13 to 14
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of RO, water recovery could be improved greatly by blending with
part of the untreated effluent to attain a desired level of TDS.
IV. CRITIQUE OF SESSION
Three papers (Papers No. 19, 21 and 23) formed an excellent
theme--desalination with the use of innovative designs for the mem-
brane and ion-exchange processes. However, Paper No. 17 dealt with
neither desalination nor advanced control technology. The process
involved was one of the most primitive ones used in the field of
environmental engineering. Except for the use of viable cercariae
in the research, the effects of other parameters studied on the
performance of a slow sand filter could be expected, either intuitively
or with common sense, e.g., the efficiencies of cercariae removal
improved with the increase in the filter bed depth and with the
decrease in sand sizes and filtration rates. The only contribution
of the paper was the generation of a few numbers which could be used
for the design of a slow sand filter to remove cercariae, even
though the effects of forming a layer of Sc.humtzdz.cke. on the removal
of cercariae were not addressed. This created just too much of a
contrast when compared with more advanced papers in membrane and
ion-exchange processes, all of which involved a respectful level of
engineering ingenuity in the development and testing of their
systems.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The control of cercariae using a slow sand filter has
limited application in improving public health in the United States.
The interesting results on desalination with the innovated Sirotherm
and the continuous countercurrent ion exchange processes may supple-
ment the shortcomings of fouling of reverse osmosis membranes in
desalinating wastewater effluents. The development of a simulated
flow cell for the evaluation of fouling characteristics of a reverse
osmosis membrane represents a step forward in evaluating the membrane
process for use in renovation of water or wastewater. With this
testing device, a more useful correlation can be established between
the results obtained from laboratory testing and from actual opera-
tion of a prototype reverse osmosis system. This opens the way for
more research to be conducted in the field of membrane areas. Since
the United States is leading in the area of membrane research and
development, the availability of the newly developed simulated flow
cell, as presented by Belfort, would certainly aid in conducting
fruitful research on membrane process applications.
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I. SESSION
A. Day: Tuesday, March 30, 1982
Hall: B
Time: 1:00 to 4:35 p.m.
B. Theme of Session: Mass Transfer; Scale Up and
Mathematical Modeling
II. REVIEWER
A. Name: Dipak Roy
B. Position and Affiliation: Assistant Professor
Department of Civil Engineering
Louisiana State University
Baton Rouge, LA 70803
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 25: "On the Mass-Transfer Characteristics
Within Microbial Systems," by M. Onuma
and T. Omura (Japan)
The diffusion coefficient within a microbial system was
determined by both diffusion and kinetic studies on the basis of
Fick's model and an effectiveness-factor model in order to predict
the mass-transfer characteristics of this system. It was found
to be dependent on the molecular weight and C/N ratio of the com-
pounds and substrates used in the diffusion study. The transitional
film thickness from a reaction-limited case to a diffusion-limited
one was found to be about 150 um in a kinetic study. The observed
diffusion coefficient in the diffusion study was of the same order
as that of the kinetic study.
The diffusion studies for DO, glucose, NH^-N and PO4-P
were performed using a two-compartment diffusion reactor and a
circulating reactor was used for kinetic studies. Diffusion co-
efficients for glucose and DO were observed to be independent of
the film thickness in the range of 70-100 ym. The observed values
of diffusion coefficients for DO and glucose in a biofilm were
found to be 10 percent greater than the calculated value in pure
water. Diffusion coefficients for glucose were observed to be
dependent on the C/N ratio of the solute. It was reported to be
constant in the range of C/N ratio of 0-10, whereas a decreasing
trend of diffusion coefficient was observed with increasing C/N
ratio above 10.
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A linear relationship between the reaction rate and the
film thickness was observed up to a critical value of film thick-
ness of approximately 150 pm. Above the critical value of film
thickness, the reaction rate remained constant. The overall
reaction was considered to be limited by the biochemical reaction
in cases of the film thickness less than the critical value,
whereas the diffusional process was the rate-limiting step above
the critical film thickness. The effectiveness factor, defined
as the ratio of overall reaction rate and the ideal reaction rate,
was observed to be dependent on the film thickness for diffusion
limited case. The effectiveness factor was one for reaction limited
cases.
Harremoes (Denmark) indicated that the experimental
aspects of the research were inspired by the work of Williamson
and McCarty and expressed the following reservations and questions:
(1) In the experiment, biofilm was made up by dispersion of
activated sludge floes onto a porous filter. Floes dispersed onto
a filter may not behave in a similar manner as a biofilm; (2) The
diffusion reactor was made up of two compartments and a slight
difference in pressure between two compartments may significantly
affect the results. How was the pressure in these two compart-
ments maintained at same level?; and (3) How was the biofilm
made non-reactive?
Harremoes (Denmark) commented on the diffusion coefficient
reportedly being 10 percent greater in biofilm than in pure
water. This is in contrast to values reported in literature which
show diffusion coefficients in biofilms are approximately 50-100 per-
cent greater than those in pure water. Diffusion coefficients have
been reported to be dependent on the C/N ratio of the sewage in
which activated sludge floes are grown. Diffusion coefficients
were observed to be 6 x 10-6 and 0.8 x 10"6 cm2/s at C/N ratio 5:1
and 50:1, respectively. The drop in diffusion coefficient at a C/N
ratio of 50:1 indicated that the bacteria were starved of N. When
bacteria are starved of N, changes in bacterial species and extra-
cellular polymer accumulation are believed to occur and may there-
fore affect the diffusion coefficient. It was felt that more infor-
mation should be provided on recirculation filters with regard to
the type of media used, possible concentration gradient in the
filter, the dissolved oxygen concentrations, and the measurement .
technique of biofilm thickness.
As the film thickness increased, the reaction rate was
observed to increase to a limit and then remained constant. This
was interpreted in the paper as a transition from fully-penetrated
film to partly-penetrated film. In a redox-reaction experiment,
two substrates, glucose and oxygen,are involved. How can it be
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assured that the transition is due to fully- to partly-penetrated
oxygen and not glucose? It appeared that at a 50 mg/I glucose
concentration, oxygen may be limiting. The critical film thick-
ness of 150 vim is not an universal value and depended on the sub-
strate concentration. Finally, the discusser felt that the use
of effectiveness factor is appropriate for first order reaction.
However, for 0 to 1/2-order reactions, this factor depended on
the bulk liquid concentration and its use may be confusing.
Onuma (Japan) responded that the pressure in the two
compartments of the diffusion reactor was balanced. In regard
to the relationship between diffusion coefficient and C/N ratio,
the interpretation may be that the resistance to pore diffusion
at high C/N ratio results in the drop in diffusion coefficient.
He also elaborated on the attached biofilm which was grown on a
fiberglass filter paper.
Holder (Australia) referred to his early work and
Williamson's work to suggest that glucose, and not oxygen, was
limiting under the experimental condition reported. He also
suggested that a better attached film may be developd by repeti-
tion of passing nutrients through the filter and scraping off the
slime layer.
B. Paper No. 27: "Scale-up and Limitation of Physical
Oxygen Transfer," by B. J. Kim and
A. H. Molof (U.S.A.)
Three different laboratory-scale rotating biological
contactor (RBC) units were constructed to study the factors con-
trolling oxygen transfer. Physical parameters were identified and
evaluated by the volumetric oxygen transfer coefficient (l^a) from
non-steady state clean-water tests. The controlling factor was
found to be the liquid film flow rate per unit volume. The turbu-
lence effect on the free water surface and subsurface volume became
comparatively less significant as disk size increased. Data indi-
cated that physical oxygen transfer contribution to the biological
treatment oxygen requirement became less significant than oxygen
transfer through other mechanisms as the disk size increased.
Physical oxygen transfer in the RBC system was studied
to determine: (1) appropriate scale-up factors, and (2) the
source of oxygen. Three laboratory-scale RBC units with 15 cm, 31 cm
and 61 cm disks were used. Other experimental parameters were
number of disks (N), peripheral velocity of disks (Vn), spacing
between disks and rotational speed. A relationship between the
oxygen transfer coefficient, K|_a, and volume renewal number, Nv,
was derived and described in earlier work. The mass transfer
coefficient was reported to be correlated to a modified Reynolds
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number by Ouano (1978). The data obtained in this study indicated
that the modified Reynolds number cannot be used for scale-up.
Oxygen transfer in the RBC system can be accomplished
from different possible sources. To determine the source of DO,
a system was developed for wiping a part of the liquid film from
the disks exposed to air. It was observed that the K|_a values
increased with an increase in liquid film area. Biological
oxygen utilization, (O2)b» reported in earlier work, and the
physical oxygen transfer, (O2)p, reported in this work were plotted
against rotational speed. It was observed that (O2)p/(O2)b de~
creased as the rotational speed decreased.
The invited discusser, Bishop (U.S.A.), recognized
the general omission of oxygen transfer rate for design of RBCs
and commended the authors for their work to include this parameter
for scale-up. The authors have criticized previous researchers
for correlating oxygen transfer rate with rotational velocity and
Reynolds number. The dependence of oxygen transfer rate on other
parameters such as disk size and spacing was correctly pointed out.
The dependence of Kt.a on volume renewal number (Nv),which includes
disk size, spacing and RPM,was validated. However, the data
were scattered at high Nv and therefore doubt exists about the use
of Nv for scale-up from 60-cm to 1.5- or 3-m diameter disks.
The wiper blade study indicated that little or no oxygen
transfer occurred if the disks were dry. The little oxygen trans-
fer that occurred was believed to due to turbulence caused by the
falling water. This phenomenon could have been verified by
collecting water draining from the disks as done in the study
reported by Bintanja. The use of clean flat disks in RBC causes
minimum turbulence and provides very little oxygen transfer. In
actuality the disks are coated with gelatinous filamentous bio-
film which increases roughness. The increased roughness may in-
crease turbulence resulting in an increase in oxygen transfer. He
also inquired about the effect of using rough or convoluted disks
on oxygen transfer.
It is apparent that disk size influenced the oxygen trans-
fer rate whereas no such effect was noticeable with regard to disk
spacing. However, the oxygen transfer rate was reported to be a
function of Nv which is dependent on disk spacing. The authors
were asked to resolve this conflict.
The results indicated that approximately 55 to 90 per-
cent of the biologically utilized oxygen came from air to biofilm.
Ouano (1978) reported that 20-60 percent of the biologically utilized
oxygen can be accounted by the direct oxygen transfer from air
to biofilm. The authors have also shown that at constant peripheral
velocity the ratio of (^p^^B decreased as disk s^ze increased.
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Thus, for full-scale RBC systems the amount of oxygen transferred
by physical means will be insignificant in comparison to oxygen
directly absorbed by the biofilm. Current research at the discusser's
laboratory indicated substantial oxygen transfer into the biofilm
from the atmosphere substantiating the findings of Kim and Molof.
If physical oxygen transfer is assumed to be a minor factor, then
the use of Ny is questionable for design of RBCs. Nv is a practical
tool for scaling physical oxygen transfer. But,if direct oxygen
transfer to biofilm is the controlling factor, then the RBC design
should be based on the exposed surface disk area and oxygen trans-
fer into the biofilm.
Molof (U.S.A.) replied that, regarding data scatter for the
plot of K. a at high Nv, he has similar questions about what will
happen at high Nv. Collection of liquid to avoid turbulence would
have been a better experimental technique, but the experiments
presented in the paper were sufficient to obtain information on the
relative contribution of the water and air phase. The roughness
and types of disk media may affect the oxygen transfer but do not
affect the biological growth.
The disk spacing was experimentally observed to affect
K|_a values. The reasons may be due to use of unmodified or unaveraged
S values. In reference to Ouano (1978), he reiterated that this study
was the first one to provide quantitative data on the source of oxygen.
In reply to the question of the validity of using Nv for design of
RBCs, it was pointed out that the work presented is a transitional
one to show that oxygen is coming from air and not water.
Harremoes (Denmark) commented on various processes where
reaction is limited by oxygen and stressed the importance of oxygen
transfer into the biofilm in the RBC system. For example, he
mentioned nitrification as the process where reaction in biofilm is
oxygen-limited for all practical purposes. He cautioned against the
danger of scaling up oxygen transfer rate on the basis of disk area.
He questioned the validity of using Nv as the scale-up factor
simply because the parameter N is not dimensionless. Finally, he
inquired if the authors' results have been compared with the results
obtained by the theoretical dimensionless analysis reported in the
work of Bintanja and Zeevalkink.
Molof (U.S.A.) indicated that according to their earlier wcrk,
nitrification was not oxygen limited and suggested that it may be
carbon limited. He agreed that normal factors cannot be used for
scale-up and expressed his inability to predict whether Nv can be
used for scale-up to large-scale system. Although Nv is not dimension-
less, this may be the best parameter available, and it gives a better
handle of the system. He indicated that the volume renewal number was
based on Bintanja's and Zeevalkink's works and their findinqs were in-
corporated in the current work.
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Watanaka (Japan) agreed with Molof that oxygen in the
RBC system comes from the air. If the biofilm is developed on
the rotation disks, then the oxygen is transported through the
attached layer which exists between the air and biofilm. Thick-
ness of such attached films are determined by the peripheral
velocity of disks. However, the air exposure cycle is a function
of the rotation velocity. As two parameters cannot be selected
for scale-up, he inquired which one of these two parameters, i.e.,
the rotating velocity and the peripheral velocity, should be used
for scale-up.
Molof (U.S.A.) stated that the peripheral velocity
is not a scale-up factor and rotational velocity should be used
for that purpose.
C. Paper No. 29: "Application of the Marais-Ekama
Activated Sludge Model to Large Plants,"
by H. A. Nicholls (South Africa)
The Marais-Ekama model was used to successfully predict
the performance of two 50,000 m3/d, five-stage activated sludge
plants used for nutrient removal. The experimental data used to
test the model was obtained by monitoring the feed, effluent and
contents of each reactor in the process at two-hour intervals for
four days. In addition, a respirometer was developed to measure
oxygen utilization rates automatically every 30 min. All data
collected were validated with acceptable COD and nitrogen balances
across the plants. The data were then compared with the steady
state and unsteady state responses of the model.
It was found that the model could successfully predict the
COD, TKN, ammonia and nitrate concentrations in the effluent and
illustrated some shortcomings in the process layouts. This indi-
cated that the model could be used by designers and operators of
large-scale plants to predict performance and highlight problem areas.
The Marais-Ekama activated sludge model has been used on
small-scale laboratory and pilot plants where the flow is easy to
control and the oxygen utilization rate is easy to measure. The
aim of this paper was to predict the performance of actual acti-
vated sludge plants using the Marais-Ekama model.
Difficulties were experienced while obtaining a represen-
tative sample and while measuring the oxygen utilization rate in
both plants investigated in this study. The first plant on which
the model was tested was the Johannesburg Goudkoppie plant which
treats 150,000 m-tyd. It is a five-stage process in which the
first and second stage are stirred reactors followed by an aeration
reactor, a stirred reactor and a reaeration reactor. The second
plant was the Johannesburg Northern Works plant, which has a design
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3
flow of 150,000 m/d through a five-stage process. Although the
Northern Works plant was similar to the Goudkoppie, its sludge
characteristics were slightly different.
The rate of COD and TKN removal predicted by the model
were in close agreement with what was obtained in practice for both
plants. The oxygen utilization rate measured in the Goudkoppie
plant was slightly out of phase from the values predicted by the
model. The reason for this discrepancy was believed to be due to
the assumption that the aeration basin was a completely mixed
reactor whereas in practice some plug-flow conditions do exist.
This discrepancy was not observed in the Northern Works plant.
The Northern Works plant was designed to treat an influent
COD of 600 mg/£. But in actual practice, the influent COD was found
to be only 270 mg/£. Thus, it was not possible to compare the design
with the operating conditions. Also, the nitrate in the effluent
was extremely high and a portion of it was removed.
In the next phase of this work, the effect of altering
the process on the model predictions was studied, but the perfor-
mance could not be improved at all. The input-data sewage charac-
teristics were then changed and the model performance was examined.
This change indicated that the nitrate could be entirely removed by
increasing the COD and the readily biodegradable fraction of the
COD. The author concluded that if the model is fed with reliable
input data, it will predict fairly accurately what is expected to
happen in practice.
Ekama (South Africa), the formal discusser, pointed
out that it was important to note that the cyclic behavior of the
total oxygen demand is satisfactorily predicted in the model. He
also mentioned that, at the long sludge age at which the plants were
operated (25 days), the variation in the total oxygen demand is con-
siderably damped with respectto the variation in influent oxidizable
matter. This aspect being accurately predicted by the model would
ensure less power requirement for the aeration equipment in the
future. On the other hand, he showed concern on the overprediction
of the ammonia concentration in the anaerobic reactor. He also
pointed out that like all mathematical models, this model
consisted of a number of kinetic constants. The inaccurate deter-
mination of these constants might lead to erroneous results.
In replying to the query over the inaccurate prediction of
the ammonia concentration, Nicholls pointed out that this was largely
due to deflocculation, which is very prevalent in case of anaerobic
sludge. The kinetic constants could be determined quite easily and
accurately as long as a single-stage small laboratory pilot plant
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was available. He also agreed with Ekama that in order to operate
such complex plants, efficient operators were very essential.
Roberts (South Africa) from the floor posed three questions
regarding this paper. He observed that the model lacked authority
in predicting the oxygen uptake rates in the two different plants.
He mentioned that the oxygen uptake rate does not depend on the
hydraulic retention time but is largely dependent on the number
and location of the surface aerators and also on the vortex cycling
rate induced by the surface aerator. Secondly, he believed that
the unbiodegradable part of the influent COD is a function of the
solids retention time rather than being dependent on the wastewater
characteristics. His third question related to the specific growth
rate of nitrifiers as to whether account was taken of the nitri-
fying organisms that were lost in the effluent from the clarifier.
Nicholls (South Africa) stated phase shift was not observed
in both plants. He also commented that the oxygen utilization rate
was independent of the location of the probes because the activated
sludge is taken in small quantities and pumped into the reactor
and then drawn back into the system. With regard to the non-
biodegradable particulate matter, it was pointed out that the model
measures the biodegradable soluble fraction also, and hence, the
effluent content cannot be said to consist of only the non-
biodegradable particulate fraction. In response to the question
on nitrification, it was indicated that at a long sludge age, little
variations in kinetic constants would not affect the predicted
values to a great extent.
Beekman (South Africa) questioned whether
Johannesburg determined the effect of balancing on the extent
of COD reduction obtained in the primary settling tanks. He
also wanted to know the effect of varying the mixed liquor recycle
ratio. The author stated that flow balancing was achieved in both
tanks. The Goudkoppie plant showed a lot of sedimentation in the
balancing tank. Due to this settlement, a significant change in
COD was observed while the TKN remained unchanged. He mentioned
the importance of maintaining the TKN to COD ratio constant while
looking into the nutrient removal. It was seen that the COD
showed a distinct decrease while the TKN remained unaltered.
Visser (South Africa) inquired on the availability
of the model in a simple form to be used efficiently by de-
signers and operators. He questioned the validity of using the
mean value of the three oxygen utilization rates in a semi-
plug-flow unit. He also wanted to know whether tracer studies
had been performed to study the phase-shift-phenomena and
suggested the use of CSTR's in series to approximate a plug
flow reactor. Nicholls (South Africa) replied that the steady-
state response could be used very easily by the operator in de-
signing a plant. Nicholls (South Africa) argued that measuring the
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oxygen uptake rate at three points was quite acceptable. The
oxygen utilization rate was corrected for the oxygen used for
nitrification; the oxygen used for denitrification was then sub-
tracted and the oxygen needed for carbon oxidization was thus
obtained. This value was balanced successfully with the influent
numbers after taking into consideration the losses in the waste-
water and the effluent.
Bernard (France) asked about the accuracy in deter-
mination of the kinetic constants which would affect the final
results. The author said that the kinetic constants can be
divided into three groups. Most of them can be classified as
those that are independent of the wastewater characteristics.
A small group can be found which is dependent on the wastewater
characteristics. These constants can be used to find the COD and
the TKN needed for the bacteria. The sludge was examined and pilot
plant tests were run independently to calculate, for example, the
desired COD and TKN concentrations.
Jenkins (U.S.A.) queried whether the model could be re-
lied upon to program aerators to match dissolved oxygen consump-
tion rates in aeration basins. Nicholls (South Africa) indicated
that oxygen uptake rates would be looked into as a control mechanism
very shortly. He also added that flow balancing together with
load balancing would also be studied at a slightly later stage.
D. Paper No. 31: "A Mathematical Model of Biological
Purification in Aerated Activated Carbon
Biofilters," by G. Martin, A-Y. Le Roux,
P. Schulhof (France)
On the basis of results obtained in the laboratory and in
a pilot plant, this paper outlined the probable mechanism of bio-
logical purification on activated carbon. At low loads, media
porosity plays a prominent role in the treatment of a water. The
biological activity which develops on the material acts in a com-
plementary fashion, allowing for continuous regeneration of acti-
vated carbon pores.
With heavy loads, there are two phases. Initially, ad-
sorption and biological regeneration are complementary. This phase
lasts three to four hours. During the second phase, development of
the biomass obstructs the occurrence of the absorption phenomenon.
This second phase lasts from fifteen to twenty hours, until the
filter is clogged. After washing, the first phase again enters into
operation.
Preliminary experimental results which led to the develop-
ment of this work were: (1) Bacteria were present in the macropores
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and on the edge of meso pores; (2) Approximately 90% of biode-
gradable materials was found in the bacteria present on the sur-
face; (3) At a low loading rate bacteria were dispersed and did
not affect physical adsorption; (4) For the treatment of non-
absorbable biodegradable substrates (ethanol), no difference was
observed when activated carbon and an inert support media were
used; and (5) Bacterial exo-enzymes may be involved in the process.
A mathematical model was formulated to account for the
bacterial growth and its migration through the filter, relation-
ship between bacteria and adsorbed substrate and the relationship
between bacteria and non-absorbed solute. A numerical solution
technique was used to predict the performance of activated carbon
biofilters under various experimental conditions.
Activated carbon column experiments were performed using
wastewater plant effluent and drinking water spiked with phenols.
N, P and other nutrients. The observed effluent COD and phenol
values were in close agreement with the values predicted by the
mathematical model. The authors concluded that the mechanism
postulated for biological removal of absorbable substrated resulted
in good prediction by the model. Non-biodegradable substates were
not investigated and the authors suggested the use of a supple-
mentary coefficient to account for the residual.
Eden (United Kingdom) noted that for the full
understanding of this work, readers need to refer to another paper
published in WcUeA Ruzanxih in January, 1982 by these authors on
a similar topic. He observed that an aerobic condition in the
experimental set-up was maintained by blowing air through the
filter—and the process was assumed to be not limited by oxygen.
He inquired if any dissolved oxygen measurements were performed
to verify this aspect. Also, he pointed out that a few sweeping
assumptions were made for the development of the model. These
assumptions need to be verified, and the model needs to be vali-
dated over a wider range of conditions such as temperature and
nature of substrate.
Eden (United Kingdom) asked why phenol concentration in the
influent was not constant. It appeared that removal of phenol
was fairly constant at a 80 percent level and wondered if this
result could have been predicted by a simpler theory.
The researchers appeared to be on less secure ground
when they move from soluble substrates such as phenol and methanol
to deal with sewage. Assuming that this sewage is settled, no
more than 50% of materials are present in dissolved form and the
rest is present in suspended to colloidal region. A good portion
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of this suspended matter is bacteria and bacterial floes. Much of
this bacterial population will be removed by passing through an
activated carbon filter. It is unlikely that the mathematical
model based on adsorption will fully account for the removal of
this nature.
Removal of organic matter from sewage by purely physico-
chemical process, even if enhanced by biological means, seems to
be unlikely due to unfavorable economics. The reason is that the
carbon is to be removed from time to time for regeneration. There
could be other applications of biologically active carbon filters,
e.g., the treatment of polluted river water with low organics to
obtain drinking water. For such treatment biological regeneration
of carbon filters may be an economic process.
The author replied that dissolved oxygen concentration
in the effluent was verified several times to be rather high--
approximately 3-4 mg/£. The variability in the influent phenol
was due to experimental problems and was considered desirable.
The extension of this model to other processes is under progress
to accommodate non-absorbing media. Application of the model to
anoxic processes such as denitrification is being contemplated.
In the biological activated carbon filter, it was ob-
served that physico-chemical processes play an important role
for the first tew hours whereupon biological processes take over
and physico-chemical adsorption is diminished. The analogy of this
process to the activated carbon process used in water treatment may
not be appropriate because of the presence of many non-absorbing
materials. In response to the question of removal of suspended
particles, it is evident that biological filters do have an im-
portant filtering role.
Fleet (South Africa) pointed out that one of the premises
that has been used in the model is the mechanism of bioregeneration.
It was proposed that the adsorbates migrate into the micropores
and then subsequently desorbed out of the micropores during biode-
gradation. He cautioned against considering such hypothesis even
if the model predictions are good because of many simplifying
assumptions made for solving the model. Also, he noted that
the model predictions are good on a short-term (hours) basis and
inquired about the reliability of the model on long-term predictions.
Martin stated that, considering the experimental conditions, it
was apparent that the substrates did not reach micropores, and
the necessity to have access to the micropores was not implied in
the model. It is evident that the substrates had access to the
meso-pores. The model was tested to predict five-six operating
cycles over a period of three months.
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IV. CRITIQUE OF SESSION
Paper No. 25 raised questions about the ideal way of
developing biofilms for diffusion experiments. Design of the
experimental set-up for such investigations is extremely critical
for obtaining good data. The critical film thickness of 150 vim
should be used with caution as it depends on the substrate con-
centration.
The results presented in Paper No. 27 answered the basic
question of the relative contribution of oxygen by the air and
bulk liquid phase. It was shown that the oxygen transfer cannot
be scaled-up during disk area or Reynolds number. This aspect
of the research has far reaching impact on the design of full-
scale RBC systems.
The Marais-Ekama Model for activated sludge process was
applied to full-scale processes (Paper No. 29). The model was
validated to predict COD and TKN removal in two large plants.
Predictions of nutrient removal by the model was poor. The reason
for such poor prediction was due to the actual COD and TKN loading
being half of the design value. However, if the plants are
operated under design load conditions, then the model was capable
of predicting nutrient removal.
The mathematical model of activated carbon biofiIters
(Paper No. 31) postulated a possible mechanism for biofilters.
Model predictions were in good agreement with observed values
of COD and phenol removal. Extension of the model to accommodate
non-biodegradable substrates, suspended solids and temperature
would be desirable for wider applications. The model needs to
be validated for making long-term predictions.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
None of the studies presented in this session were con-
ducted in sufficient detail to permit direct implementation of the
results. However, some direction was provided for future research.
Results presented in Paper No. 25 should be reproduced
under well defined experimental conditions and future research
emphasis should be placed on the determination of mass transfer
through biofilms using complex substrates such as phenol and
chlorinated organics.
The results presented by Kim and Molof (U.S.A.) answered some
key questions on physical oxygen transfer. This paper was clearly
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a transitional one. Further work should be continued to determine
the ideal scale-up factor. Effect of biofilm, roughness and type
of disks on oxygen transfer needs to be evaluated.
Validation of Marais-Ekama model to predict the per-
formance of full-scale activated sludge plants is of great signifi
cance for the design and operation of activated sludge plants in
this country. The model can be used to pinpoint some of the opera
tional problems in existing treatment plant. Future studies on
using this model to determine control parameters such as oxygen
uptake rate, flow and load balancing will be of great importance
for practicing engineers.
The model for an activated carbon biofilter suggested
a probable mechanism of COD and phenol removal. Findings of this
study with reference to non-adsorbing substrates have limited the
use of carbon filter. Also, the model needs to be validated
under various operating conditions such as temperature, types of
substrates and particulate matters. It appears that the results
of this study may not be of any practical use at this time without
future research.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: B
Time: 9:00 a.m. to 1:00 p.m.
B. Theme of Session: Physical/Chemical Waste Treatment
and Metal Removal
II. REVIEWER
A. Name: David Jenkins
B. Position and Affiliation: Professor of Sanitary Engineering
University of California
Berkeley, CA
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 33: "Granular Activated Carbon and Preozonated
Granular Activated Carbon Treatment for
Biologically and Physically-Chemically
Treated Wastewater Effluents," by A. Netzer
and J. L. McNutt (U.S.A.)
This paper described pilot-plant testing of activated carbon
column treatment of both biologically treated, physical-chemical
treated and mixed biologically plus physical-chemical treated effluents.
Results with and without preozonation of effluents were presented.
Improved treatment efficiency and extended carbon life were obtained
for preozonated effluents. Much more data (additional parameters and
extended periods of performance) were presented. The author indicated
that optimization of column loading and ozone dose were being inves-
tigated currently.
In the realm of activated carbon studies, this paper could
be classified as applied research that investigated the effect of a
pretreatment step on performance in terms of gross parameters such
as BOD, COD and TOC. It was pointed out that for all these para-
meters, the prototype plant performed significantly better than the
pilot plant (e.g., BOD removal: pilot plant 39%, prototype plant
31-86%; COD removal: pilot plant 25%, prototype plant 43-63%).
These significant differences raised questions as to the true
similitude between the pilot plant and the prototype designs. The
effluents treated by carbon were very high in suspended solids (SS)
due to the poor performance of the prototype treatment plants.
Discussions raised the question of the effect of SS on the experi-
ments. While no specific response was given, the author noted that
initially the carbon columns were backwashed with air scour four
times daily. Later, sand filtration was used prior to the carbon
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columns. Agreement with the author's reported benefits of preo-
zonation was voiced by workers from the Daasport pilot plant in
Pretoria, South Africa. They are, in addition to preozonation,
studying CI? pretreatment, optimization of preozonation and the
use of aerobic carbon columns. Swiss work showed an even greater
benefit for preozonation in treating water for potable uses:
with no preozonation, regeneration was required in five months,
while with preozonation, columns were regenerated once every
three years; only 12% carbon loss had been experienced in six
regenerations.
B. Paper No. 35: "The Nature of the Reactions Between
Chlorine and Purine and Pyrimidine Bases:
Products and Kinetics," by J. G. Gould
and T. R. Hay (U.S.A.)
This paper was an investigation into the rates and products
of reactions of chlorine with three nitrogen-containing hetero-
cyclic bases, i.e., uracil, cytosine, and caffeine. Reactions of
chlorine and these bases were found to differ significantly in rate
and nature of products. Caffeine yielded a complex array of ring
cleavage and rearrangement products in a relatively slow reaction.
True ring chlorination with the production of 8-chloro-caffeine
occurred in these systems but was relatively minor process. The
reaction was fairly slow, high-pH dependent, and yielded an array
of labile combined-chlorine species and chloride. Chlorine species
analysis gave little evidence of the formation of carbon-chlorine
bonds. Uracil reacted rapidly with chlorine undergoing considerable
true chlorination with the formation of a product consistent in
character with 5-chlorouracil. Kinetically, the reaction was strongly
pH dependent. While small quantities of chloramines were produced,
they were labile, arising most likely as a result of ring cleavage.
Cytosine produced a complex array of products including chromato-
graphable organic chloramines. Fifty percent of chlorine added to
cytosine was manifested as combined chlorine of high stability.
Evidence for various N-chlorocytosines was presented.
The author expressed caution in extending results of
chlorine reactions with one compound to other compounds of similar
composition—for example, the reactions of chlorine with cytosine
are quite different from those with 5-methylcytosine. However, the
author stated that it would not be necessary to study reactions with
every single organic nitrogen base since, with the accumulation of
more data on such compounds, some ability to predict such reactions
may become evident. The toxicity of the products was not well known-
Ames testing showed weakly positive mutagenic effects but the author
cautioned that false positive results with Ames testing could not
be discounted. The inability of wet chemical methods for determining
chlorine in forms such as 8-chlorocaffeine was noted. Such methods
lump these chlorinated organic nitrogen compounds into "dichloramine
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active" substances; amperometric methods are unsatisfactory be-
cause of the unreactivity of these materials. Gas chromatographic
analysis of reaction products gave the same result as the milder
thin-layer chromatographic techniques and thus the products did not
decompose under the gas chromatographic conditions employed. The
author suggested that the chlorinated organic nitrogen compounds
formed would be readily reduced by sulfur dioxide under conditions
representative of wastewater dechlorination.
C. Paper No. 37: "The Fate of Some Metal Species: Lead,
Cadmium, Zinc in Surface Water During
Biological Sand Filtration—Effect of
Preozonation," by F. Erb, D. Delabre,
J. C. L. Hopitault, A. Phi 1ipo, P. Thomas
and A. Brice (France)
Slow sand filtration of raw water reduced its metal con-
tents with up to 50 to 60% reduction being obtained for Cd and Pb.
Preozonation solubilizes particulate Cd and Zn and breaks complexes
of metals with organics such as humic material and converts them
to free metal ions which then are eliminated more readily. Preo-
zonation provides for a greater efficiency of metals removal by
sand filtration than does flocculation.
Discussion centered around two issues. First, several
points on experimental validity were raised—the limits of metal
detectability by the techniques used were questioned; the loss of
metals between their addition to feedwater and dosing on to the sand
columns was pointed out and the author agreed that precipitation and
adsorption onto vessel walls could occur; the question of changes
in metal speciation in the five days between addition to feedwater
and use in experiments was raised; the validity of using 0.45 ym
membrane filters to differentiate between soluble and particulate
metals was questioned; there was agreement between a discussor and
the author that preozonation could liberate metals from organic
complexes and lead to better removal in a sand filter however.
Perhaps ozonation could could also lead to higher biodegradeability,
a better flow in the sand filter and therefore a better removal of
metal.
The second issue of discussion was raised by the observa-
tion that the authors' experiments were conducted on metal levels
lower than those stated in the European Economic Community (EEC)
Directives on water for human consumption. Points raised were:
why conduct such a study if the metal levels are already acceptable?
The EEC directive is a maximum, and we should try to do better.
We should not waste money in trying to achieve quality better than
the EEC directive. All parts of the EEC directive are not mandatory,
but governments must take the EEC directive into account when setting
their own standards, which may be more stringent than the EEC direc-
tive. The EEC directive and other standards are maximum allowable
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values, not the most desirable; scientists should conduct research
to produce water of better quality. The matter was unresolved.
D. Paper No. 39: "A New Configuration of the High-Lime
Process with Sludge Recirculation for
Magnesium Recycling," by E. Idelovitch
and A. M. Wachs (Israel)
The paper described a process for magnesium recycling
in the lime treatment of oxidation pond effluent for phosphorus
removal. A portion of the sludge produced was dissolved in treated
effluent. The effluent, which was enriched with Mg, is recycled
to the lime addition unit. The modified process results in more
readily dewaterable sludge [i.e., it contains less Mg(0H)2L
elimination of need to add supplementary MgCl2, and reduction
of lime dose to reach a given high pH value. Accumulation by
dissolution and recycle of potentially harmful materials such
as heavy metals and boron does not occur to a significant degree.
Several points relating to the process engineering aspects
of the proposed scheme were raised (e.g., effect on sludge thickening,
effect on solids loading of solids handling devices, need for
equilibrium studies especially in view of classification of solids
that takes place in centrifuges, cost comparison with recycling).
The author indicated that such matters would be addressed in future
pilot pTant work.
The author agreed with a discussor from South Africa that
Fe (II) addition could be used as a flocculant instead of Mg in the
high-lime process but indicated that their waters were hard and had
a high alkalinity so that it was beneficial to use the Mg available
in them. Quoting experience with the use of CO2 regeneration of
lime sludge from a low pH lime treatment of water, a discusser from
South Africa indicated increases of organic matter in the water
released from the sludge that was eventually recycled to the
treated water to increase the organic content of the effluent.
The author stated that in his system, a secondary polishing pond was
available; and in addition, he believed that the use of high pH
in the lime precipitation process improved organic matter biode-
gradeability in the secondary ponds. The author indicated that these
secondary polishing ponds also served as recarbonation basins; no
problems had been encountered in them due to CaC03 deposition.
After a period of several years, only a few millimeters of CaC03
has been found on the bottom of the ponds.
IV. CRITIQUE OF SESSION
These papers varied greatly in approach, application and
quality. Two (Papers No. 33 and 39) were strictly applied investi-
gations, one was a strictly mechanistic study (Paper No. 35), and one
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a laboratory investigation of process performance (Paper No. 37).
Paper No. 33 was of limited applicability because of its empiricism;
Paper No. 37 also was of limited value because of questions of
methodology. The basic information on chlorination of organic
nitrogen bases presented by Gould and Hay was of high quality
and should be viewed as the first step in the right direction down
the difficult road to understanding the chemistry of these pro-
cesses. Paper No. 39 contained material of merit but left un-
answered many questions of feasibility and economy that will have
to be answered by future pilot plant work. Papers No. 33 and 37
emphasized the potential value of preozonation as a process for
improving the performance of organic carbon and also in aiding
metals removal by biological and (slow sand) filtration. Its
use in both potable water treatment and in the tertiary treatment
of wastewater effluents is deserving of further study.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The significance of the papers presented in this session
is somewhat limited: the two points that stand out are (1) the
value of ozonation as a treatment process prior to activated carbon
(The extent of the benefits of this process and the mechanism of
changes that take place during ozonation and subsequent treatment
by carbon need to be studied in depth.) and (2) the complexity of
the interactions between chlorine and organic nitrogen compounds
typical of those found in treated wastewaters and waters. Further
fundamental investigations along the lines of that reported in
this session are deserving of support.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: B
Time: 2:00 to 5:00 p.m.
B. Theme of Session: Wastewater Treatment
II. REVIEWER
A. Name: Foppe B. DeWalle
B. Position and Affiliation: Associate Professor
Department of Environmental
Health
University of Washington
Seattle, WA 98195
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 41: "An Integrated Low Cost System for Treatment
of Potato Processing Wastewater Incorporating
Anaerobic Fermentation and Phosphorus
Removal," by J. G. Parker, B. J. Lyons, and
C. D. Parker (Australia)
Anaerobic fermentation was used to treat potato processing
wastewater with a BOD of 48,000 mg/£ followed by 350 mg/£ lime
treatment for phosphorus removal of the combined effluent and the
low strength wastestream. After 0.350 1/min pilot plant studies,
a 1362 £/min full-scale plant was started beginning in 1980 and
gave BOD removal efficiencies of 89% as compared to 93% for the
pilot plant. The wastewater was suitable for discharge to the
domestic sewer. Both the pilot and full-scale plant gave gas pro-
duction of 390 I gas/kg BOD removed with 55% of the gas consisting
of methane at a BOD load of 6.6 kg B0D/m3. The full-scale anaerobic
digestor had a 6.9-hydraulic detention time, a sludge age of 50 days
and MLSS of 25,000 mg/I. The final plant effluent met all sewer
discharge requirements except for organic nitrogen (51 mg N/£). The
mud and phosphate sludge was disposed of on potato-growing land.
B. Paper No. 43: "The Adsorption Behavior of Cationic
Polyelectrolytes in Dissolved Air," by
R. Gehr and J. G. Henry (Canada)
The effectiveness of cationic polyelectrolytes with a
FeCl3-conditioned activated sludge in a dissolved air flotation
system was evaluated with respect to molecular weight and ionic
charge. The tests were conducted with 2100 mg/£ of MLSS and
115 mg/I of 02. The 2 x 10^ MW and the 10 x 10° MW polymer resulted
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in a thickening parameter of 1300 and 1200, respectively, an effluent
SS of 27 mg/£ and 24 mg/£, repectively, and an extrapolated monolayer
coverage of 4.3 mg/g and 7.4 mg/g, respectively, during batch
testing. The greater degree of adsorption of this high molecular
weight polymer reflected its greater extent of looping of segments
into the solution. The minimum effluent SS were reached at a coverage
of 3.5 mg/g for both polymers, corresponding to a polymer residual
of 0.5 mg/£ and 1 mg/£ for the high and low MW polymer, respectively.
Higher polymer dosages did not further reduce effluent SS but in-
creased the thickening parameter resulting from the displacement of
water from the floe by air bubbles. The zeta potential changed
from -16 to a positive value at the first appearance of polymer
residual in the solution. An extrapolated monolayer coverage of
17.2 mg/g was obtained for the full-scale testing of a 8 x 10& MW
polymer with a cationic charge 30% lower than the polymers used in
the batch tests.
C. Paper No. 45: "The Performance of an Ultrafiltration
Pilot-Plant for the Closed Loop Recycling
of Textile Desizing Effluents," by
C. A. Buckley, R. B. Townsend, and
R. Groves (South Africa)
The author described the first 16 months of spiral wound
membrane ultrafiltration pilot plant testing to recover the polymer
PVA from 25% of the 75°C desizing effluent of a cotton mill. The
18,000 MW spiral ultrafiltration membrane concentrated the 10*> MW
PVA from about 20 g/£ to 60 g/l after which the retentate was
reused in the sizing operation, while the permeate was reused in
the washing operation. The total PVA loss during each recycle
loop was 25% which has to be replenished through makeup to bring
the retentate concentration from 60 g/£ to 80 g/£. The desizing
effluent had to be pretreated by either filtration using a 10 pm
candle filter or centrifugation to remove short fibers that other-
wise would block the feed spacer mesh. As a result of the recycle,
the COD load was reduced by 900 tons/year and the unit paid for
itself in approximately 1.25 years.
D. Paper No. 47: "Leaching Characteristics of Industrial
Metal Finishing Wastewater Treatment
Plant Solids," by T. H. Goodgame and
P. W. Barnett (U.S.A.)
Metal phosphating and pickling sludges generated during
lime precipitation were placed 20-29 cm deep in a lysimeter and
leached with distilled water at a rate of 510 cm/y. Maximum initial
concentrations of 812 mg/£ COD; 590 mg/t Na; 432 mg/I Ca and
2050 mg/£ SO4 were noted at pH values ranging from 7.1 to 9.2
with sulfate and iron exceeding drinking water standards. The
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simulated 10-year landfilling of the sludges resulted in a maximum
leaching of 64% of the calcium (sample A) and 63% of the sulfate
(sample B), while less than 1-6% of the metals were leached.
IV. CRITIQUE OF SESSION
Paper No. 41. Alternative product recovery schemes such
as starch recovery by ultrafiltration or waste conversion to yeast
for cattle feed were not evaluated. The plant used the wet peel
method for skin removal; however, much lower waste loads are generated
by the dry mechanical peel method. Although the latter method is
more expensive, the lower wastewater treatment costs often make the
combined process cheaper.
Paper No. 43. Adsorption was expressed in milligrams
instead of moles. As~~the high molecular weight polymer has five
times greater weight than the low molecular weight polymer, the
adsorption of the former is much lower on a molar base. The use
of the Langmuir isotherm is questionable as the looping is in ob-
vious conflict with the postulated complete monolayer coverage.
It is, therefore, better to use Henry's constant at infinite dilution
or to use the Freundlich isotherm. Insufficient data are given
for a comparison of the bench-scale batch testing and the full-
scale continuous testing with respect to effluent SS and sludge
thickening. In addition, the continuous testing used a polymer
not evaluated during batch testing.
Paper No. 45. Many critical data are missing from this
paper such as the flowrate during pilot-plant testing, the membrane
surface area of the pilot plant, the volume percentage permeate of
the overall unit and of each of the three stages. The data in
Fig. 1 do not distinguish between different recycle flowrates and
temperatures, the data in Fig. 2 do not distinguish between dif-
ferent recycle flowrates, and the data in Fig. 3 do not specify
temperatures. Were all these data generated for a single module
or for the tapered series in batch or continuous mode?
The data in Fig. 3 do not include the 0% PVA line for a clear
membrane using tap water to determine whether it has a similar
flux shape as the 0% wash water line. No data were given of the
long-term flux decline during the 16 months of operation. What
was the percentage downtime during this period? The washwater
rate is given per kg of cloth while other parameters are expressed
per meter of cloth. The PVA mass balance does not close. As
much as 25% of the PVA is lost during each cycle with 6% of the
PVA remaining in the cloth, 10% of the PVA removed in the filtration/
centrifugation and 9% unaccounted for. As a result of the closed
loop, the water use was apparently reduced from 3 m3/h by
29% to 2.2 m3/h; however, sizing usually represents only
about 40% of the plant flow. The COD was apparently reduced
by 900 tons/year; what was the COD of wastewater before and after
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recycling? As a result of the recycling, a gradual buildup of the
soluble COD in the retentate is expected: how much was it and did it
influence the quality of the washed cloth? The pilot unit was
apparently designed for a 5 £/m2-h flux rate (0.75 m3/h with 150 m^)
while the full-scale design used 7.4 £/m2 . h (3 m3/h with 405 m2);
what was the rationale for this? Why was the full-scale unit
operated in a batch mode instead of designing for fewer elements and
using a continuous mode? What was the tapering design for the full-
scale unit?
Paper No. 47. The major criticism of this study was the
use of distilled water instead of a simulated leachate with a high
concentration of acetic acid and a pH of 4.0-5.0, as is often found
in a young landfill. Under these conditions much higher metal
concentrations would have been leached out initially. Anaerobic
instead of aerobic conditions should have been selected, resulting
in the reduction of sulfate to sulfide, which in turn would pre-
cipitate several of the heavy metals.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Paper No. 41. The paper described the first integrated
plant of its kind in the potato processing industry based on
separate treatment of high-strength waste with energy recovery
and low-strength wastestreams for phosphorus removal. Many plants
in the United States combine wastestreams for joint treatment
thereby greatly reducing the potential for energy recovery. Due
to energy savings, this process was considerably cheaper than con-
ventional spray irrigation requiring 240 hectare and anaerobic/
aerobic lagoon treatment requiring 60 hectare, as often used in
the United States. The studies showed that 4000 mgH of sodium
and 5000 mg/I of fatty acids were not toxic while 10 mg/£ of
sprout-inhibitor (chlorophenyl isopropyl N-3 carbonate) was toxic
to the anaerobic fermentation at an average pH of 7.4.
Paper No. 43. The study provides a model to interpret
dissolved air flotation (DAF) data. As the DAF process requires
as little as 10 min, compared to 1-3 hours for conventional gravity
thickening, a much smaller-sized unit can be selected resulting in
a lower cost. A DAF process should be evaluated as an alternative
for difficult-to-settle sludge, as much smaller sludge floes are
still acceptable. The limitations of DAF are the ability of the
small air bubbles to attach to the sludge floe and the necessity
to use polymers to provide a sufficiently strong floe. Since all
tests were done with sludge conditioned with FeCl3 to provide
phosphorus removal, less positive results could be expected with
regular activated sludge.
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Paper No. 45. Despite the missing information, the
paper showed that reuse of sizing polymers is possible using mem-
brane ultrafiltration resulting in the elimination of the wash-
water stream often accounting for 40% of the total wastewater
stream and 65% of the COD load. Since energy costs are generally
higher in South Africa than in the United States, the payback
time should even be less than the estimated 1.25 years.
Paper No. 47. This study has no major significance to
the United States metal sludge disposal practices, as unrealistic
leaching conditions were selected. This opinion was shared by
most participants of this session.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: B
Time: 9:00 a.m. to 12:30 p.m.
B. Theme of Session: Sludge Treatment and Disposal
II. REVIEWER
A. Name: Alan H. Molof
B. Position and Affiliation:
III. DESCRIPTION OF SESSION PAPERS
Associate Professor
Department of Civil and
Environmental Engineering
Polytechnic Institute of New York
Brooklyn, New York
A. Paper No. 49: "Aerobic Thermophylic Stabilization of
Sludge versus Anaerobic Digestion and Other
Kinds of Sludge Treatment at Middle-Sized
Plants with Respect to Power Conservation
and Economy," by P. Wolf (Federal Republic
of Germany)
The paper covered a comparison of aerobic thermophylic
stabilization (ATS) and anaerobic digestion with gas recovery (AD)
for medium-sized wastewater plants in the Federal Republic of
Germany. The temperature of 2 open parallel ATS reactors on a once
per 2-day feeding schedule ranged from 25 to 38°C in winter. The
higher temperature of a 2-stage ATS covered reactor system was
35-40°C in the first reactor and about 50°C in the second reactors.
The air temperature was about 10-12°C. A temperature record for
the whole year ranged between 30 to 50°C.
3
- The open reactors had a volume of 75 m and were fed
18.5 m /d on alternate days. The sludge was a mixture of primary
and secondary sludges thickened to about 4% solids. The detention
time was 6.9 days.
Characteristics of a well stabilized ATS sludge were
less than 100 g/kg VS-d for specific rate of 02-respiration;
less than 5 g TPF/kg VS for enzymatic activity; less than
35 g/kg SM for ether extract; greater than 10 days for lead acetate
test; and less than 10 s/g SM for capillary suction time (CST).
The two open parallel ATS digesters differed in performance although
both had 2.7% solid matter, one had 61.3% volatile matter and a pH of
7.8 while the other had 61.8% volatile matter and a pH of 8.3.
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The energy factors of the ATS open reactors were listed as
energy input at 85 W/m3 of usable reactor volume and energy con-
sumption at 18 kWh/m3 of thickened raw sludge. The air rate used
for oxidation was minimized to conserve heat loss. The operating
temperature was found to be a function of the total sludge solids,
tank insulation and the air rate. The open reactors exhibited a
scum layer of about 0.5 m which acted as an insulator.
Data on energy cost, running cost, capital cost and
annual cost were presented in graphical form for various sludge
processes. These included open digestion, aerobic thermophylic
stabilization, raw sludge dewatering, combined aerobic stabiliza-
tion, and heated digestion with no gas, with heating and with
power generation. A summary of the cost data is as follows:
(1) For a plant with about 20,000 population equiva-
lents (PE), open digestion and the ATS process produce equal
and the lowest annual costs. The combined aeration stabilization
(CAS) process costs are markedly higher and are equal to the AD
process without use of digester gas. The annual costs increase with
the use of digester gas for heating and power generation.
(2) For plants of 50,000-100,000 PE, the ATS process
costs approximately equal the AD process costs. At 50,000 PE
they are more economical than the CAS process due to improper
power splitting in aeration to meet the differences in oxygen con-
sumption for day, night, weekday and weekend operation.
(3) At 250,000 PE the AD process with or without gas
utilization is the most economical.
The nominated discusser, Bernard (France), stated that the
process cost comparison can be a hazardous exercise. He stated
that ATS process uses more energy than the AD process. There is
government encouragement toward energy recovery even though it is
often not based on economics. He stated that it is difficult to
accept long-term storage for the ATS process and asked if there was
information on pathogen levels in the series ATS process in summer
and winter and if it can be compared to the AD process. It was noted
that there are substantial differences in energy recovery and
asked: What is the explanation of differences between raw influent
and raw sludge?
He said that ATS is more vulnerable than AD and that the
choice between ATS and AD is not all that obvious. He noted that
AD can give energy independence while ATS cannot.
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The author replied that it was found that it was only
possible to reclaim 30% or 1.9 kWh/m^ digester gas, although
manufacturers speak of reclamation of heat as 47% of the energy
input. He agreed with the comment on government encouraging
energy conservation. In small plants, he noted that there is no
problem with the ATS process. However, sludge can be stabilized
by storage in open ponds for six months.
Matthews (United Kingdom) stated that sludge treatment
should never be considered without including sludge disposal. He
raised points: (1) What is the volume per PE produced after
final thickening for the ATS and AD processes? If the ATS pro-
duced more sludge, then cost of transportation would rise; (2) It
is important that sludge quality be taken into account. For
example, if ATS has a higher pathogen level, the sludge would be
less acceptable in agriculture, and increased constraints in dis-
posal would increase disposal costs; (3) The author was asked to
comment on the fact that the ATS sludge will have less free ammonia
than AD sludge. This would result in less acceptability as a
fertilizer and thus increase disposal costs.
Beekman (South Africa) asked three questions on the
utilization of digester gas for power generation or direct drive
to a compressor. These were: (1) Is the gas pressurized for all
plants or is there a mixture of pressure and nonpressure? If so,
what is the pressure being used for the machines?; (2) What is
the machine type? Is it based on pure gas or a mixture of gas and
fuel oil? If so, what is the percentage of fossil fuel used?;
(3) What is the average size of the generator?
The author replied that ATS sludge is higher quality than
the AD sludge due to higher temperature operation. If the detention
is six to eight days and the temperature is greater than 50°C, one
could assume that there would be no practical problems as concerns
bacteria. At high temperature, there will be no ammonia oxidation.
Utilization of digester gas works with normal pressure vessels.
Usually the engine is gas driven. There are very few cases where
the gas-fuel oil is used.
B. Paper No. 51: "Simultaneous Pasteurisation - Digestion
(SPD- Process)," by G. Kugel (Federal
Republic of Germany)
The author stated that the object of the simultaneous
pasteurization-digestion (SPD) process is a safe and robust process
using digester gas with adequate pasteurization by submerged com-
bustion heating. The advantages of submerged combustion heating were
indicated to be: (1) spontaneous heat exchange; (2) high degree of
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contact between gas and liquid; and (3) high efficiency due to
heat recovery. The disadvantages were indicated to be: (1) flue
gas deodorization; and (2) application only for large plants when
using a digester gas supply.
The wastewater treatment plant for 100,000 PE (population
equivalents) consisted of primary and activated sludge processing.
The digester gas from storage was used to provide the fuel for the
submerged combustion heating. The flue gas was passed through a
compost filter for deodorization. The sludge was heated to 80°C
in winter and 85°C in summer and digester temperature was 35-38°C.
Cooling water for the heated sludge at 80-85°C was from the secondary
settling tank effluent. Energy sufficiency was only reached in
the SPD process, not in post pasteurization.
A question has been raised concerning the effect of the
high heat of pasteurization on the sludge. Although Lipmann has
shown little effect in the laboratory, there is still a question
if the sludge is affected. The wastewater contained a majority of
potato-processing waste high in organic material, i.e., starch. ~
The volatile solids in the influent were 35 kg/nr and were 14 kg/m
in the effluent, or 60% digestion efficiency. To improve the diges-
tion process, it is proposed to try FeS04 to improve the thickening
step. The volatile acids were low at about 70 mg11 during peak
potato processing in the spring. The median gas yield during the
winter peak was about 28 m^/m^ sludge with a 90/10 probability ratio
of about 1.45.
The SPD process yielded sufficient gas to avoid purchasing
outside energy. In 1,980-81 the calculated gas surplus was 30.5 per-
cent, even with the equipment not at an energy optimum. For the
future one could expect flue gas-gas engines or turbines.
The nominated discusser, Baines (United Kingdom), stated
that the use of the term "simultaneous" is difficult to understand
since pasteurization actually precedes digestion. Perhaps "sequential"
would be a better word and still retain the initials, SPD.
The crux of the matter is the pressure for pasteurization.
Is the pressure coming from the government as indicated in the
Federal guidelines of 1972? What is the present situation in Germany,
i.e., is pasteurization recommended for land application or could
another method,such as irradiation, be used?
The SPD process does not prevent recontamination during
storage and before land application. The effect of the SPD process
on the most important pathogens is not included. Could the author
provide information on bacteria, parasites such as tape worm and
others? The enterobacteria densities are given only at the beginning
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and end of the five-month operation. Could information be provided
for various points in the process before and after pasteurization,
after digestion, and after storage before land application?
During the pasteurization it could be presumed that
methanogenic and other bacteria would be greatly reduced. The
remaining bacteria are seeded by the digesting sludge and the
count increases rapidly during digestion to provide a good seed
sludge. The bacterial status of the digestion is of interest,
i.e., do the surviving methane bacteria increase partially due
to reduced competition? This may partially explain the high gas
yield or could this be due to the potato starch itself? If due
to the potato starch, then the results would be similar if post
pasteurization or digestion alone were used.
Several points were cited: (1) How is the digester
heated? The cooling water is not used; (2) The input sludge
temperature is controlled in a narrow range, yet a temperature
range of 28-70C is quoted; (3) The loss of energy in the cooling
circle will be improved as indicated.
The tabulated energy of the water and sludge pump in-
dicated that 45% of the energy (28% sludge and 17% water) was con-
sumed in the cooling circle. If the cooling water is not used,
then the energy is lost. However, the heat dissipated in the
digestion-pasteurization process requires no cooling water and
therefore saves energy.
In summer the starch would be lower and gas would be
reduced. Could the extra energy required be justified compared
to the digestion-pasteurization process or the pasteurization pro-
cesses such as irradiation?
Pasteurization before and after digestion has been tried
at the Cape Flats Wastewater Treatment Plant in Capetown. Could
someone comment on this experience with a less specialized sludge?
The author replied that he accepted the term "sequential"
in place of "simultaneous" and agreed it was a better term. During
the last 10 years, he stated that certain regulations have been
made by the government for removal of parasites from sludge before
disposal on land. Presently, the government is preparing legis-
lative revisions which will be published before the end of April
(1982). These regulations or guidelines will state that no sludge
can be put on pastures or fields without pasteurization and will
be effective in 1986. Sludge disposal on agriculture land will
require an effective public relations image. Other pasteurization
methods are permitted. For example, Co^O irradiation is in operation.
However, this use is troublesome to the general public.
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Results of Breer in Switzerland indicate that after the
submerged combustion heating, there were 102/m£ of enterobacteria.
This was also the count with effluent. Parasite eggs are killed
off below the operating temperature. Based on these counts, if
confirmed, there is no need for final storage facilities to be
covered. Post pasteurization is okay. However, it is significantly
worse than prepasteurization. A gas yield of only 15 m3/m3 was
obtained with an automated system. Operation was more difficult
and costly. After three-five months, the enterobacteria count
stabilized at 10^ - 103/m£.
Beekman (South Africa), in floor discussion, stated
that Cape Flats, the first large-scale plant using pasteurization
in South Africa, has only just started up. The plant has sufficient
digester insulation and heat transfer area to maintain the proper
digester temperature.
At St. Galons, Switzerland, he observed similar results
as presented here indicating that pasteurization before digestion
gave much better results. It is of interest to note the large
increase in gas of 15-25%. Other pasteurization plants were
observed in Switzerland that were inoperative, possibly due to
having pasteurization after digestion. Most of the material
disposed has been in the liquid phase. Does the author have an
experience in the dewatering characteristics of the final product?
Coker (United Kingdom) stated that an important principle
which has been stated by the author is to have requirements for
sludge treatment which consider the final disposal method and thus
produce a sludge fit-to use, i.e., use in agriculture requires
pasteurization. The results presented are in line with results
with partially pasteurized agriculture and horticulture soils which
get markedly increased mineralization following heating to 55-60°C.
What would be the percent increase in cost to add the pasteurization
step to an existing digester plant?
Schlegel (Federal Republic of Germany) stated that heating
to 80° causes a large degree of hydrolysis and improved dewatering,
thereby indicating pretreatment by pasteurization is desirable.
This was only shown last year in Japan at the Second Anaerobic
Digestion Conference.
Is it possible that the surplus gas was due to starch
waste and not necessarily due to the domestic portion? What was
the wastewater influent BOD and COD?
The author answered that recycling or agricultural use
is done in the liquid phase. About 25 years ago, artifical dewatering
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was tried and abandoned. There is no experience on drying. The
additional cost for post pasteurization in 1971 was 5.5 million DM.
He agreed that the high gas yields were due to starch.
The potato season ends in May with nothing in May and June. The
gas yield at the time is much lower at 15 - 18 nw/m^ sludge.
During holidays there is poor operational performance under these
nonideal conditions. It is ideal only during the potato season.
C. Paper No. 53: "Inhibition Modelling in Anaerobic
Digestion," by A. C. Duarte and
G. K. Anderson (Portugal and United
Kingdom)
Sludge digesters have failed in the field due to some
type of inhibition, and there is an interest in defining the
conditions responsible for these failures. Andrews (U.S.A.) has
proposed a comprehensive theory that it was the effect of the
substrate, volatile acids, which were inhibiting the activity of
the methane bacteria. There seemed to be some doubt as to
whether the inhibition was due to the substrate itself or whether
it was the effect of the volatile acids reducing the pH. The
aim of the work was therefore to test the inhibition theory of
Andrews.
The work was carried out with 25-I anaerobic contact
digesters. At this size, there has been some difficulty in inter-
preting the data due to buildup of growth on the walls of the
reactor. The digesters were fed in two ways, i.e., sodium acetate
was added to stimulate methane production and glucose was added
to produce volatile acids. When the digester wall was scraped,
failure conditions were more easily reached. At constant feed, the
pH decrease resulted from increased acetic acid loading. When the
pH dropped from 6.5 to 6.3, the methane production was reduced
by 65% and acetic acid level increased from 750 to 1500 mg/I.
At a pH of 7.6, the increase in acetic acid of 750 to 1500 mg11
showed no inhibitory effect. This suggested that inhibition could
be controlled by pH.
Other variables such as hydraulic retention time (HRT)
were tested. At the same HRT, a higher pH gave a higher COD
reduction, i.e., a 10% difference. At different HRT and at con-
stant pH, the effluent COD values were the same. This confirmed
that Monod kinetics was not a good model for the methane phase.
Under good operating conditions acetic acid was the
primary volatile acid formed. But as the pH was allowed to drop
to 5.5, a high proportion of the acids formed were propionic and
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butyric. If the digester was allowed to stand, the pH slowly in-
creased, the CO2 slowly recovered and the methane production
remained low until the pH was 6.4. This recovery was partially
due to the wall growth. The implication is that if the pH is
greater than 6.5, inhibition will not take place in a carbohydrate-
rich reactor if other inhibitory agents are not present. Inhibi-
tion did occur with high unionized volatile acid, irrespective of
the pH. It thus appeared that inhibition was due to a mixture
of volatile acids and pH.
Other work was done with anaerobic filters with much
higher wall growth. There appears a wider tolerance range for
the pH-substrate combination and therefore, a more robust system
than the anaerobic contact digester.
Other observations included the formation of propionic
acid which is not significant in normal operation. However, if
the digester failed, the propionic acid produced appeared to limit
the rate of recovery. Propionic acid appeared to have some role
in the recovery of digesters after failure.
The final point is not in the paper. Recent work has
been done by Anderson on ammonia and sulfate toxicity. Sulfate
problems are due to (1) sulfate toxicity, (2) corrosion of gas
burners, and (3) 10% reduction in methane production. A simple
solution based on nutrient control has been tried which prevents
inhibition of methane production and plant corrosion due to
sulfide.
The nominated discusser, Marais (South Africa), stated
that he did not believe that the paper, containing lots of informa-
tion, was written in a clear and understandable manner and that the
values hidden in the paper should have been brought out more clearly.
He stated that the object of the paper was to apply Andrew's equation
on growth rate inhibition using acetate and glucose substrates.
Andrew's equations are in terms of the undissociated
acetate species. Since the undissociated acetate species is related
to the total acetate concentration through the pH and pK values
for dissociation of acetate, the use of the equation is not straight-
forward. The authors did not deal with this aspect presumably
since they assumed it was weak acid-base chemistry. An explanation
from the authors would be valuable on how they dealt with the inter-
action between undissociated acetate and free acetic acid.
The authors used the Monod equation with a factor for
inhibition included. The substrate concentration was the undissociated
acetic acid, not the total acetic acid concentration. For a plot of
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the equation versus total acetic acid concentration, the fraction of
undissociated acid would vary at every pH. If a K-inhibition value
was assumed, the plot of growth rate versus the undissociated acetic
acid concentration would rise and fall, unlike the Monod equation
which rises and levels out. In addition, this plot would change
for every pH.
If at a specific growth rate, i.e., the independent
variable, a line is drawn horizontal to the concentration axis, it
will intersect the curve at two points. The first crossing indi-
cates stability and a tendency to equilibrium, while the second
crossing indicates a failure tendency even though both are at the
same specific growth rate. The authors took these concentration
values and interrelated them with the concentration expressed as
total acetate for various pH values. The line separating stability
and instability zones in the paper represented 10 mg/£ of undis-
sociated acetic acid and was supported from other information. In
terms of the authors' theory, even though it is a parametric
approach, it provides information on why the digesters failed,
which the discusser considered an interesting contribution.
However, one must bear in mind that the inhibition effect
shown by the equation used is empirical and not based on any bio-
chemical mechanism. Also, the transition from an unfailed to a
failed reactor will be associated with a changing pH and acetate
condition, and it is not evident which of these values should be
plotted on the diagram. Furthermore, as pointed out by the authors,
the data in the healthy digester area does not consider failure
due to washout.
In the propionic acid studies, the authors consider that
propionic acid breakdown was the rate-limiting step in the methane
fermentation of substrates such as glucose. This phenomenon has
also been observed by other investigators. However, it has long
been thought that short chain fatty acids are broken down by at
least two organisms symbiotically. The one species breaks down
propionic acid to acetate, carbon dioxide and hydrogen and is
considered to be inhibited by the hydrogen. The second species,
a methanogenic organism, breaks down the acetate to methane and
carbon dioxide and also combines the carbon dioxide with the
hydrogen to form methane. This implicates hydrogen as an important
intermediary.
The author replied that the growth equation will lead to
two solutions as referred to by Marais. In the lower solution will
be the stable region, and in the upper region, the region past the
maximum growth rate, is in the unstable region.
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Concerning the propionic acid, no comment was made except
that the thermodynamics and biochemistry are at present unsatisfactory
and more work is needed.
Spies (Federal Republic of Germany), in floor discussion,
stated that in the anaerobic contact process, one cannot control
biomass if the biomass cannot be separated. He asked what were
the authors' experiences with biomass separation.
Weichers (South Africa) stated that the author referred
to scale-up problems such as wall growth at laboratory scale was
important. In South Africa, experience with anaerobic treatment of
wine waste at laboratory, pilot and full scale showed that the
load that can be applied can differ by two orders of magnitude
as well as the types of settling rates obtained. He asked what
scale should be used and what precautions should be observed. He
added that settling cannot be scaled up or scaled down.
Pohland (U.S.A.) stated that it is unfortunate that the
author (Andrews) of the inhibition model was not present. The
model is not a comprehensive model and included only one acid-base
equilibrium that can occur in an anaerobic system. Fortuitously,
the organic acid contribution to the array of equilibria conditions
is very important and often the reason why one can get correlations.
However, one should not overlook other acid-base equilibria as
well as complexation reactors that can affect the pH which, in
turn, will affect the amount of ionized species present. It should
be indicated to the authors and others that they should not use
absolute values of concentration of unionized species since it is
a function of the total species concentration as it relates to pH.
It has been indicated that inhibitors other than acids
can affect efficiency. Since the model is based on acid-base
equilibria, it does not account for other inhibitors. Sulfate
studies bring into mind the inter-relationship between ORP and pH
which has been discussed and researched in the past. One cannot
uncouple acid-base pH from the EP. He concluded that inhibition
modeling is a game played in curve fitting to explain data, and
it tends to sophisticate our ignorance about what is really
causing the inhibition.
Loewenthal (South Africa) stated that the authors noted
that washout or sludge age is not included in the model while they
state that wall growth which affects sludge age is an important
factor in the results. If, in fact, the sludge age did affect the
results, it would indicate the inhibition model does not have much
meaning.
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Kroiss (Austria) stated that they have run experiments
for nearly one year on acetic acid wastes with high content of
sulfur compounds. They have run pilot plants of 4-m3 volume
with wastes of high acid concentration up to 2000 mgH of total
volatile acids. No failure was evident even up to 5 g/£ of
volatile acid, but there was about a 33% drop in COD reduction
(75-80% down to 50%). However, sulfate was reduced to sulfide
with the most important figure being the ratio of COD reduction
to sulfate in the influent due to the equilibrium between liquid
and gas phases.
The author replied that he felt he could not really
comment on the growth rate measurement. It was thought to be
simply a measure of the volatile solids changes. He noted that
the laboratory-scale reactor was 25-I in volume, while the pilot
scale was 6 nw and the full scale was 90 m3. As pointed out,
it is not really possible to scale-up, especially settling. The
laboratory reactor was mentioned as a precautionary note. Experience
with laboratory and pilot scale have shown similar indications.
Full scale has not been run long enough for meaningful data. It
appears that it is possible to obtain reasonably reliable data
from pilot plants of 6-10 m3.
It should be pointed out that the authors improved the
inhibition model by including such parameters as carbon dioxide,
bicarbonate and ammonia. The authors used the simplified version
to see if it could reasonably explain the results and so far,
perhaps fortuitously, it seems that results are in the range of
the model. However, the cautionary suggestion is noted.
The sulfate effect has been handled in a different manner
by the authors. The technique is to relate the sulfate to enzyme
blockage which the speaker did not think is related to 0RP.
On the subject of wall growth versus sludge recycle,
the volatile acid effect was different on the two types of growth.
The wall growth was less sensitive to the volatile acids and its
influence on the results was not in proportion to the small amount
of biomass but rather to its insensitivity to the external acetic
acid.
The author's experience has suggested it is possible
to operate at several thousands of mg/I of acid and that operation
at 5000 mgft is not a difficult point to reach.
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D. Paper No. 55: "Process Integration in Sludge Management,"
by R. I. Dick, D. L. Simmons and Y. Hasit
(U.S.A.}
The author stated that improvements in sludge treatment
processing has resulted from the study of individual processes
such as thickening, anaerobic digestion and dewatering without con-
sideration of process interaction and integration. If process
interaction, such as thickening reducing the anaerobic digester
size, is considered as part of an optimally designed system, then
the result will not include optimally designed individual com-
ponent processes. The basis for optimal designed systems is to
get the best out of each process in view of the overall scheme,
not in view of the individual process.
The study procedure consisted of three major components,
performance models, cost models, and an optimization procedure.
The performance models were mathematical descriptions of the per-
formance of wastewater and sludge treatment processes. The
development of fundamental models was limited to the present state
of knowledge. Since optimization using traditional rules of thumb
is not possible, an attempt was to develop as fundamental a model
as possible. In some cases, this was not feasible due to the current
state-of-the-art and empirical models were developed. Such an
example was sludge conditioning.
The second component was cost models developed from American
practice. This is the weak point since accounting practices tend
to be poor and there is difficulty in attributing costs to individual
processes. It is also difficult to attribute costs on the basis of
design and operational parameters. Much of the cost data was taken
from an EPA report done by Metcalf and Eddy Inc. several years ago.
The third component was a computer optimization procedure
with the objective of minimizing total annual cost. It was subject
to constraints with some related to performance standards such as
effluent requirements, heavy metals and nitrogen levels for land
disposal and minimum anaerobic-digester detention time. The optimi-
zation procedure was developed by Ratner and Fox.
Some of the 29 quality parameters included nutrients and
heavy metals in the soluble and particulate forms so as to be able
to track them from process to process. Although fundamental models
were used for thickening and dewatering equipment, empirical relation-
ships were used between concentration and sludge settling velocity
and between specific resistance and pressure differential.
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The effect of the mean cell residence time for an inte-
grated treatment system was illustrated. The system was primary
treatment, activated sludge, combined sludge gravity thickening,
, anaerobic stabilization, chemical conditioning, vacuum dewatering,
and trucking 32 km to agricultural land. The overall annual cost
was lowered as the mean cell residence time was reduced.
Reduction of anaerobic digester and vacuum filtration
size by increasing the sludge thickener size resulted in an
overall reduced annual cost. The cost reduction of the digester
was more than the increased cost of thickening. Significantly,
the optimal thickener size was larger than conventional design
practice.
It is important to note that thickening can have a
significant effect on chemical properties, in addition to physical
properties of sludge suspensions. The increase in thickener size
resulted in a digested sludge higher in cadmium and nitrogen due
to less dilution. Land application is controlled by plant avail-
able nitrogen so that less sludge will have to be applied and the
cadmium level determined by the degree of thickening.
The effect of the transportation mode on the overall cost
of a large 2.2 m^/s plant showed ocean disposal was the cheapest
for an anaerobic digested sludge. For agricultural land disposal,
it appeared to be best not to dewater the sludge unless the
distance was greater than 30 km.
The effect of the transportation mode on the overall cost
for a smaller (0.44 m^/s) plant showed that liquid sludge disposal
by truck was the choice up to nearly 100 km. The expense of
dewatering was not recovered in the transportation cost. Barging
to sea was not particularly advantageous for a plant of this size.
For small plants, energy was not an important consideration
in the total plant use. However, in larger plants energy did become
a significant factor. In a previous paper, Wolf pointed out that
aerobic thermophylic digestion was competitive at the smaller plant
size which is in support with these figures.
As energy costs change, the method of integrating sludge
processes will change. As energy costs increase, it would be prudent
to use chemicals and thickeners to decrease energy-intensive vacuum
filter size and increase digester size to maximize the gas yield,
even though at present anaerobic digesters are allowed to go to
minimum allowed sizes.
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The present preliminary attempt of sludge management
has shown that there are many instances of identifying what is
not known. There are major gaps related to the physical properties
of sludges. There is a lack of information on the effect of
design and operation of sludge generation processes on the physical
characteristics of the sludge produced. There is little information
on the properties of a resulting mixture of two types of well-defined
sludges. There is little information on sludge processes as relates
to the physical properties such as from aerobic and anaerobic
digesters.
The formal discusser, Kugel (Federal Republic of German),
commented on the 30 parameters used to describe the processes and
asked which ones have proved to be truly relevant. The approach
used has been rational and has presented some positive comments
on sludge thickening, sludge transport and land disposal of sludge.
Of particular merit is the suggestion that the system must be looked
at in its entirety. The optimization should include the end products:
sludge, effluent and gas.
Capital costs can matter, yet the author assumed a constant
7% amortization rate. Has there been a variation in the 7% and, if
so, has a sensitivity analysis been done? If there has been a
range in the percent interest, what is the confidence level in the
week? With reference to the periods in the economic analysis, the
discusser stated that the present worth factor is dependent on the
period of analysis and the interest rate used. With different
interest rates or present worth factors, the breakeven point can
be shifted. At this point, all investments with a high initial
cost will be preferred while on the other side, it will be reversed.
The author replied that all of the 30 parameters were
used with settling and dewaterability properties being used most
frequently. Nitrogen was important in land application rates,
although some indicate phosphorus is more important. Heavy metals
were used in determining land application rates.
The 1% interest rate used was based on that recommended
by the United States government at the time the paper was written,
but the current rate is far above that value. A sensitivity analysis
was done for interest rates up to 15%. Although it was found that
costs were affected, there was no difference in the process inter-
action for the processes considered. The only period of amortiza-
tion used was 20 years. It could be assumed that, based on interest
rate changes, changes in the amortization period would change the
total cost but not significantly change process interactions.
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In floor discussion, Kroiss (Austria) asked if the
process scheme of thickening, centrifugation and incineration
had been modeled. He also asked if modeling of the long-term
effect in thickening, including temperature effects versus sludge
dewaterability, had been done.
The author answered that incineration had been found to
be noncompetitive. Although at the time of the work the fuel cost
was much lower, it appeared that incineration would be the choice
only when there are other complicating factors, and not economics,
were used. There has been no modeling on the long-term effect of
thickening.
Jacobson (South Africa) asked for comments on where land
disposal is not possible, should activated sludge residence time
be as short as possible even if incineration is used?
The author replied that for incineration, the reduction
in sludge volume accompanying long mean cell residence time is
not worth the price nor is the improvement in physical properties
worth the price.
Roberts (South Africa) asked that a figure showing the
significance of energy costs as a fraction of plant size be plotted
on a larger scale with some indication of the percentage of the
plants that fall into various size categories. It appeared that the
distinction of significant energy costs in small versus large
plants was lost. There would be substantial savings to owners of
small plants if they use energy necessary for certain processes rather
than avoid using it.
The author answered that he will probably not replot the
figure on a larger scale since it would indicate a degree of accuracy
that does not exist. It should be emphasized that a larger percentage
of the plants are small and are on the lower rising part of the curve
where energy costs are not as important as is usually thought.
Von der Emde (Austria) asked the author'if he considered
the degree of treatment at the low sludge age values as well as
the cost-benefit. The author replied that all solutions shown were
subject to the effluent quality requirements of 30 mg/I of BOD
and 20 mg/£ of SS. The sludge age was not reduced below the point
where the effluent quality requirement was not met. The very
steep part of the curve at low mean cell residence time was
due to the assumption that nitrification was not sustained at three
days but was sustained at five days. The steep portion of the curve
between three and five days was due to the increase in the oxygen
requirement for the onset of nitrification. No ammonia or nitrogen
removal standard was considered.
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Jenkins (U.S.A.) stated that the paper seemed to
advocate mixed thickening of primary and waste activated sludge.
He asked if separate thickening would be better such as gravity
thickening for primary sludge and dissolved air flotation for
the waste activated sludge.
The author replied that very little information existed
on the effect of mixing primary and secondary sludges. Calcula-
tions based on thickening characteristics of each do not yield
the mixture characteristics. Some laboratory work was done to
develop a model which indicated a nonlinear effect. This is the
weak point in the model. Based on the model, it is ordinarily
better to combine sludges when using gravity thickening. They
did look at the effect of separate thickening before mixing. The
recollection was that for very big plants it was a worthy scheme,
and for small plants it was not.
Bahrs (Federal Republic of Germany) questioned the place
of digestion in relation to incineration. If there is no digestion,
there is a high organic mass to the incinerator. If there is di-
gestion, gas is produced and there is a reduced organic mass to
the incinerator. He questioned the author on the dewaterability
change from digestion.
The author replied that it is prudent to question if
digestion should precede incineration. Digested sludge will
carry smaller amounts of mass and smaller amounts of water into
the incinerator and thus improve the economics of incineration.
He found that it was nearly a breakeven event. For large plants,
it seemed better to digest first while for small plants, it was not.
Based on the uncertainties, the author concluded he did not know
the answer. There is great uncertainty on what the digestion
does to dewaterability. From the preliminary laboratory results,
it was indicated that there was a deterioration from digestion.
In the model reported, it was assumed that there was no effect
on dewaterability from digestion. This question remains an unknown.
IV. CRITIQUE OF SESSION
Paper No. 49 expressed combined costs consisting of
running, energy and capital costs in comparing various sludge
treatment processes. It was pointed out that energy costs have
an increased significance when a national goal is energy inde-
pendence. The question of pathogen kill in view of land disposal
was not covered in sufficient detail for the ATS process. The
effect of plant size, i.e., small versus large, on process selec-
tion was emphasized. However, it was pointed out that proper
plant operation of such factors as power splitting, gas engines
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and energy planning could alter the process selection, i.e., by
favoring anaerobic digestion to a higher degree. The paper
appeared to be part of a continuing discussion on the use of
anaerobic digestion or other competing processes based on plant
size especially for smaller plants.
Paper No. 51 concerned data from a plant that received
more potato waste than domestic waste, thereby narrowing the
value of the paper. The process title was incorrect in meaning,
but a correct title was suggested by a discusser. The process
was pasteurization before digestion. The use of pasteurization
was emphasized when considering land disposal. It was stressed
that in the Federal Republic of Germany, pasteurization is to
be required before agriculture land disposal although this process
has been used as a rule in the past 15 years. Pathogen data
were not available in this paper. Of special interest was the
microbiological aspects of the digester and digested sludge put
on the land. The place of digestion after pasteurization instead
of before raised many questions, some of which were not answered.
The formal discusser of Paper No. 53 stated that the in-
formation in the paper should be brought out more clearly. He
challenged the authors use of a parameter in the inhibition
equations. The use of the particular inhibition equation used
was criticized for its simplicity and avoidance of other active
components. The effect of scale-up of laboratory, pilot and
full-size plants was brought up in the floor discussion.
Paper No. 55 acted as an integrator of the three previous
papers on individual unit processes by emphasizing the concept of
an overall sludge management system. The paper concentrated on one
flow scheme which restricted the scope of the paper although this
was expanded during the floor discussion. Many examples of areas
where lack of knowledge exists were given. The question of plant-
size effect on process selection was discussed in view of the present
paper as well as that of Paper No. 49, which reinforced each other.
The smaller relative importance of energy in smaller plants was
stressed strongly.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The use of aerobic thermophylic digestion (ATS) is
especially suited to smaller plants and was found in this case to
be superior to aerobic digestion and anaerobic digestion. The
process does require a high volatile solids content. The process
might be valuable in the smaller plants in the United States.
Increasing the degree of stability of the ATS sludge is an area that
needs further research.
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The use of sludge pasteurization is not practiced in
the United States. However, as land disposal of sludges increases,
this approach to eliminate the pathogen hazard certainly has merit
in comparison to other methods. The apparent success reported
for pasteurization before digestion would suggest a significant
study of the microbiological aspects involved.
The subject of inhibition in anaerobic sludge digestion is,
has been and will be of great interest in the United States. These
results are certainly applicable to United State water pollution
problems. The impact of propionic acid and hydrogen as an important
intermediary are major research needs.
The subject of process integration in sludge management
is now being studied with reference to United States water pollution
problems. The research needs concern areas such as the physical
changes resulting from mixing different kinds of sludges, costs
data on the proper basis, and the effect of design and operation
on the resulting sludge characteristics.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: B
Time: 2:00 to 5:35 p.m.
B. Theme of Session: Biological Nitrification and
Denitrification
II. REVIEWER
A. Name: Paul L. Bishop
B. Position and Affiliation: Professor of Civil Engineering
University of New Hampshire
Durham, NH
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 57: "Elements of the Inhibition of Nitrifying
Bacteria," by G. Martin and Y. Richard
(France)
This paper examined the inhibitory influence of mineral
and organic pollutants on the biokinetics of ammonia oxidation to
nitrates by a mixed culture of nitrifying bacteria. The purpose
of the study was to determine the concentration at which various
heavy cations, phenol and trichlorophenol become inhibitory to
nitrifying bacteria. These studies were carried out using laboratory-
scale batch and continuous-flow activated sludge units and using a
glass column filled with activated carbon or biolite to simulate a
fixed film submerged filter. Inhibitory concentrations were deter-
mined by measuring the nitrification rate and the growth rate for
various concentrations of the selected toxic material.
The inhibitory effects of nickel, cadmium, copper and
zinc were investigated. The authors reported that in no case
was toxicity observed when the cation concentration in the waste-
water was below 1 mg/£. The authors further stated that the maximum
rates of inhibition observed for the concentrations of cations
evaluated varied from 25 to 88%. Inhibition was reported to be
due to adsorption of the metallic ions on the floes containing the
nitrifying bacteria and resultant blocking of enzyme mechanisms.
In order to determine the actual state of the cations
added to the feedwater (free or precipitated with phosphates,
carbonates, OH" and NH^ ), the authors conducted a side study
to measure the amount of free cation in solution after addition to
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a buffered water containing CaC03- The results indicated that very
little of the cation added remained in solution; generally, there
was less than 1 mg/I.
Bacteria present in the fixed-film system were found to
generally be less sensitive to inhibition by heavy metals than
the free bacteria in the activated sludge systems. Little or no
nitrification inhibition was observed in the activated carbon
filter column at metal concentrations as high as 22.5 mg/£.
Investigations of the effects of phenol and trichlorophenol
on nitrification were performed using batch reactors. The addition
of phenol caused a cessation of nitrification for a period of time,
after which nitrification resumed, but at a reduced rate. At the
end of the aeration period, the phenol remained undegraded. The
authors stated that this was due to a gradual adaptation of the
bacteria to the presence of the phenol. With trichlorophenol, there
was an increasing inhibition of nitrification as the concentration
increased, similar to that found for heavy metals evaluated. The
amount of toxicity reported was substantial, reaching 98% at a
trichlorophenol concentration of 12.5 mg/g VSS.
The inhibitory effects of organic compounds in submerged
filters depended upon the adsorptive properties of the filter media.
With activated carbon as the support medium, no inhibition by phenol
was observed because the phenol was completely adsorbed by the
activated carbon. With biolite, a clay material which absorbs little
phenol, there was complete inhibition of nitrification. The support
media in a fixed film reactor may therefore be chosen to help mitigate
the inhibitory effects of a toxic organic compound.
The invited discusser, Jenkins (U.S.A.), questioned the
validity of the results presented because the toxicity thresholds
presented were based on total cation concentrations added to the
feedwater, rather than the amount of metal actually in solution,
even though the authors demonstrated that the total metals in
solution were several orders of magnitude less than that added.
Jenkins further stated that the authors ignored formation of metal
ion complexes with constituents of the feedwater (hydroxides,
carbonates and aqueous ammonia). He presented log-concentration
versus pH diagrams for the metal-ligand systems used which showed
that for the pH range used in the experiments, the major soluble
metal species for nickel, cadmium and zinc were the hydrated
cations, while for copper the major soluble species was the aqueous
copper carbonate complex, followed by the copper ammonium complex,
and then finally by the cupric ion. Since the toxicity of metals
varies widely with speciation (for example, copper carbonate is
virtually non-toxic to fish while copper ions are highly toxic), it
is essential to know what metal species are present when performing
toxicity studies.
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Jenkins (U.S.A.) stated that lack of consideration of metal
precipitation caused the authors to misinterpret their toxicity
data. The authors reported that inhibition of nitrifers increased
with increasing metal concentration and then fell off to a con-
stant value. They proposed that this was due to a toxicity thres-
hold for the metals. Jenkins (U.S.A.) felt that this finding could
be explained by the fact that as one adds more and more metal, one
reaches the solubility threshold of that metal, after which the
concentration of metal ion in solution remains constant resulting
in a constant degree of toxicity. He concluded that there would
be great difficulty in applying the authors' data on metal toxicity
to nitrifers in any general fashion or to waters other than those
used by the authors.
Martin (France) agreed with Jenkins (U.S.A.) that solubility
calculations indicated that a high degree of precipitation can occur in
the feedwater, but he felt that pK calculations were not very accurate
with activated sludge because of its complexity.
Neufeld (U.S.A.) suggested that it would be better to
measure the metals actually on the sludge floes as opposed to
using the concentration in the bulk liquid, since toxicity will
be caused only by the metals in contact with the nitrifers. Martin
agreed but stated that it is much easier to measure the soluble
metal concentration than to measure either metal concentration on
the floe or speciation in the liquid.
Matthews (United Kingdom) asked whether the authors
had attempted to distinguish between production rates of nitrite
and nitrate. Since there are two distinct organisms involved and
NtX/LOAomoncu, species are generally much more sensitive than
UitM.oba.cXoA species, the inhibitory effects should be different.
However, Martin responded that they did not detect the presence
of nitrite in their samples, indicating that the inhibition was
on NytfJioAomona.4 species.
B. Paper No. 59: "Biological Nitrification in an Up-Flow
Fixed Bed Reactor (UFFBR)," by G. M. Faup,
A. Leprince and M. Pannier (France)
The authors proposed a kinetic model to represent
ammonification and nitrification occurring in upflow-fixed bed
reactors (UFBR) receiving direct air injection into the support
medium. Fixed bed reactors were investigated rather than the
activated sludge process because an UFBR contained greater con-
centrations of active nitrifying organisms and, consequently,
could be considerably smaller than comparable activated sludge
reactors.
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A pilot-scale UFBR receiving effluent from an activated
sludge reactor was used in this research. Analysis of the average
ammonia profiles in the reactor indicated that at filtration rate
of 5, 7.5 and 10 m/h, the ammonia nitrogen concentration decreased
linearly with height in the reactor. This linearity indicated
that ammonia was not limiting and that the ammonia oxidation rates
was at its maximum over the whole height of the reactor. The
concentration of active nitrifying biomass was determined based
on the ammonia removal rate in the reactor, the reactor retention
time, and the Monod equation. The biomass concentration was found
to be primarily dependent on filtration rate and filling material
characteristics, and to be independent of height within the
reactor. When the filtration rate was reduced to 3m/h, the ammonia
profile was no longer linear but instead was exponential, indicating
that the ammonia was limiting. In addition, active nitrifying
biomass concentrations varied with height.
Comparison of the UFBR system with a pilot-scale nitri-
fying activated sludge system showed that it was possible to
reach active biomass concentrations eight to nine times higher
in the UFBR than in the activated sludge system.
The authors also modeled the transformation of organic
nitrogen into ammonia nitrogen and compared their model with
results from their pilot-scale UFBR. The computed and measured
soluble organic nitrogen profiles correlated very closely. Organic
nitrogen removal was far from complete before the wastewater
exited the reactor, thus limiting the overall conversion of nitrogen
compounds to nitrate.
Additional findings included the observation that in-
creasing the air/water ratio resulted in increased nitrification,
attributed to the greater turbulence, and that substantial reduc-
tions in soluble COD and suspended solids also occurred.
Neufeld (U.S.A.), the assigned discusser, stated that
the authors presented valuable field data which confirmed intuition
concerning biofilm nitrification kinetics, but that the model
presented was oversimplified. In particular, the model was based
on applying kinetic data taken from activated sludge nitrification
systems to the UFBR system. Neufeld (U.S.A.) indicated this would
result in an underestimation of biokinetic constants because the
Reynolds Number and umax values should be higher in the UFBR system.
He suggested the development of a predictive model based on funda-
mental parameters, such as diffusional effects, biofilm thickness
and specific surface area of the support media. He questioned
the use of the nitrifying biomass concentration as presented, since
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substrate removal was riot a function of total biomass, but rather
a function of the biofilm exposed to the bulk flow. Thus, film
diffusion as influenced by turbulence becomes a critical design
parameter, as was alluded to by the authors when they found that
increasing the air/water ratio increased the degree of nitrification.
Leprince (France) responded that he would like to use a more
extensive model, but their purpose was to find a simple model
to compare the effects of various hydraulic rates for use at
the industrial development stage. The simple model presented
was easier to use to quickly select a filtration rate which
can be used at full scale.
Harremoes (Denmark) questioned the statement that ammonia
was not the limiting factor. He stated that it is necessary to
distinguish between stoichiometric limitation and rate limitation.
He also disagreed with the interpretation by the authors and Neufield
(U.S.A.) concerning the role of increased air/water ratio on in-
creased nitrification. Harremoes (Denmark) stated that recent bio-
film kinetic research shows that oxygen is usually the rate-limiting
substrate in nitrification and that the increased rate of nitri-
fication resulting from increasing the air/water ratio was due to
increased oxygen concentration in the biofilm. Using oxygen trans-
fer calculations, the oxygen profile through the reactor could be
determined. Applying this to the model would make it a better
predictive tool.
Leprince (France) responded that he could not state whether
oxygen was the limiting substrate or whether the increased Reynolds
Number was the main factor, but he stated that the oxygen concentra-
tion in the reactor never dropped below 4 mg/I. Neufeld (U.S.A.) agreed
that the oxygen concentration was high enough to prevent oxygen
limitation and that the reason for increased nitrification was the
increased turbulence achieved. Holden (Australia) reported that
the question of whether oxygen was limiting in biofilms could be
determined by examining the diffusion coefficients and concentra-
tions of the substrate and oxygen at the biofilm surface. Dansk
(Federal Republic of Germany) stated that the role of increased
air/water ratios could be resolved with further studies using
different gas mixtures of nitrogen and oxygen.
C. Paper No. 61: "Simulation of Nitrification and Its
Dynamics in a Rotating Biological Contactor,"
by Y. Watanabe, H. C. Bravo and K. Nishidome
(Thailand, Japan)
The authors proposed a pseudo-steady-state model of
nitrification in partially submerged rotating biological contactor
systems. Steady-state substrate concentration profiles within the
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biofilm cannot be assumed because the ammonia flux to the biofilm
is a function of its spatial position as it rotates alternately
in the air and liquid phases, but the authors stated that the
fully submerged steady-state model proposed adequately models
overall results in terms of the average ammonia flux to the bio-
fl im.
The steady-state model was based upon molecular diffusion
with a simultaneous zero-order nitrification reaction within the
aerobic or active biofilm. At steady-state, the transfer rate of
the substrate into the biofilm was equal to its flux at the biofilm
surface. The proposed theory stated that the rate of nitrification
per unit biofilm surface area may be expressed as the product of an
overall rate constant and a steady-state bulk ammonia concentration.
The overall rate constant consisted of two coefficients, one of which
described the transport of ammonia to the biofilm surface and the
other described the diffusion process with a simultaneous zero-order
nitrification reaction within the active biofilm.
A computer simulation of nitrification in a partially
submerged RBC was developed and operated under varying conditions.
Comparison of the simulation results with experimental results
from the steady-state model showed that the nitrification rate
predicted by the model could be almost equal to the average nitri-
fication rate of each element of biofilm indicating that the
steady-state model could be used for a partially submerged RBC.
However, the zero-order nitrification reaction was found to hold
true only for ammonia concentrations in excess of 3.0 mg/I.
The authors also used the model to study the nitrification
process in the dynamic state. Varying ammonia concentrations were
imposed on the simulation study using a pulsed format. It was
observed that during changing bulk substrate concentrations, at
first there was some transient rise of the mass flux at the biofilm
surface, but only for a relatively short time interval, followed
by a new steady-state mass flux. Because the transient period
was found to be very short, the authors assumed that pseudo-steady-
state conditions could be used when the system is in the dynamic
state.
The model was verified experimentally using a laboratory-
scale RBC unit operating under pulsed load conditions. The experi-
mental data fit very closely to the data derived from the dynamic
model. The rate of ammonia oxidation in the biofilm was constant
for the entire length of the experiment, indicating that the
nitrifiers were working at maximum efficiency at all times, inde-
pendent of the residual ammonia concentration. This verified
the assumption of a pseudo-steady-state in the biofilm.
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The authors stated that very high ammonia concentrations
during transient periods resulted in substrate and product inhibi-
tion caused by free ammonia, but that the inhibition was not
permanent and could be removed.
The invited discussion was prepared by Saunders (U.S.A.)
and presented by Chian (U.S.A.). He emphasized that the model
presented is only applicable to wastewaters high in ammonia nitrogen
and devoid of organic matter. The model accounted for neither
BOD removal nor denitrification.
Saunders (U.S.A.) disagreed with two assumptions used in
developing the dynamic model. Rather than assuming that nitrifying
bacteria exhibit a very small lag in growth rate when exposed to
sudden changes in ammonia concentrations, as proposed by the authors,
he suggested that it would be more appropriate to assume that sub-
strate uptake by dormant organisms would occur without a significant
lag. He also disagreed with their assumption that ammonia concentra-
tions up to 60 mg/£ would not inhibit nitrification. He stated
that inhibition by ammonia was a function of pH, that free ammonia
was the inhibiting form, and that ammonia concentrations as low as
0.1 to 1.0 mg/£ are inhibitory to UiXn.oba.cXoA. At the pH and ammonia
nitrogen concentration conditions used in these studies, bulk-
phase free-ammonia concentrations would have varied from 0.5 to
1.9 mg/I , which would have inhibited N-cbiobacXeA but not NiXsio&omoncu>.
This would have resulted in high effluent nitrite and low effluent
nitrate concentrations, as was found in all cases by the authors.
Saunders (U.S.A.) concluded that inhibition by free ammonia occurred
throughout all of the steady-state and dynamic tests, thus greatly
limiting model verification.
Watanabe (Japan) replied in these studies, NiXAotomoncu, were
not inhibited even by relatively high levels of free ammonia. However,
he did agree with Saunders (U.S.A.) concerning inhibition of nitrate
oxidation by free ammonia. He further stated that nitrification
occurred within a very small thickness of the biofilm and that the
concentration of ammonia in the biofilm is considerably different
than that in the bulk liquid.
Dick (U.S.A.) noted that heterotrophic activity was
ignored and questioned what the effect of cell lysis products
would be. Watanabe (Japan) responded that an organic-carbon-free
synthetic wastewater was used in order to develop a simple model.
The effect of these organics from cell lysis on the system was un-
known.
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D. Paper No. 63: "Effect of Denitrification on the pH in
Biofilms," by E. Arvin and G. Kristensen
(Denmark)
This research, concerned with the effects of biological
denitrification on pH in fixed biofilms, showed that the pH in
the interior of the biofilm can be considerably higher than the
pH in the bulk liquid. This is believed to be due to resistance
to diffusion of bicarbonate and carbonate produced from the
oxidation of a carbon source. The paper presented a model for
the pH profiles in denitrifying biofilms and the experimental veri-
fication of that model.
Calculations for the pH profile involved mass balances
for nitrate, total inorganic carbon and alkalinity, together with
ion equilibrium equations for the inorganic carbon components and
the water. To avoid the use of complicated numerical methods,
a simplified two-step analytical procedure was used which, unfor-
tunately, resulted in a pH profile which was discontinuous. The
discontinuity occurred at the point in the active biofilm where
the concentrations of carbon dioxide and carbonate become equal
(i.e., at the depth where pH = 8.4).
A laboratory-scale, rotating-drum, fixed-film reactor
was used to experimentally verify the model. Measurements for
pH could be made in the bulk liquid and at the biofilm/support
medium interface by use of an electrode built into the reactor
wall. It was assumed that the pH at the wall was the same as
that at the bottom of the active zone of the biofilm. All experi-
ments were performed with the pH of the bulk liquid less than 8.4;
feed-water nitrate concentrations were varied to vary the active
biofilm thickness. Results from these experimental studies match
very closely those predicted by the proposed theoretical pH model.
The diffisional coefficients for nitrate, carbon dioxide
and bicarbonate in the biofilm were found to be roughly 50% of
the values in pure water. Reaction rate values were presented. The
pH effect was influenced significantly by the alkalinity in the
bulk liquid. Larger pH increases resulted when the alkalinity in
the bulk liquid was low.
The authors discussed the possible effect of the Donnan
potential created by the ion concentration distribution at the
biofilm/bulk liquid interface. This should have the effect of
increasing the concentrations of all cations, including H+, in the
biofilm compared to the bulk liquid, thus depressing the pH at the
biofilm surface. However, attempts to measure the Donnan factor
in the experimental studies were inconclusive.
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Discussion of this paper was begun by Cornier (France).
He stated that the authors had provided a good theoretical explana-
tion for biofilm pH increase due to diffusion resistance in the
biofilm. However, he felt that diffusion through the bulk
liquid/biofilm interface could also be significant and questioned
whether a lack of turbulence at the interface could be controllinq
diffusion. The author responded that all experiments were done at
100 rpm and that previous studies had shown that there was no
influence on reaction rates when the rotational speed was increased
above 30 rpm. Therefore, the reaction rates were completely con-
trolled by diffusion and reactions within the biofilm and were
independent of liquid film diffusion.
Cornier (France) asked whether the methanol added as
a carbon source would have an effect on membrane expansion. Arvin
(Denmark) replied that he did not think the methanol would have any
effect because of the low concentration present.
Arvin (Denmark) remarked that pH changes in the biofilm were
important because they could play a role in such things as the
precipitation of calcium phosphate inside denitrifying biofilms.
Roberts (South Africa) reported, however, that he had never found
calcium phosphate needle crystals in denitrifying activated sludge.
Jones (Canada) questioned whether the results presented
here for denitrifying biofilms could be extrapolated to include
pH changes in free floe. The author responded that he had done no work
with floes, but he expected that the results would be similar to
a biofilm. Nozaik (South Africa) asked whether the pH effect
would go deeper into the biofilm if the biofilm was thicker. The author
replied that this would depend on whether volatile acids were pro-
duced since the deeper zones would be anaerobic. If methanol was
the primary carbon source, there would be no large production of
volatile acids to depress the pH and the pH effect would not be
affected. This may not be true for other organic carbon sources,
however.
IV. CRITIQUE OF SESSION
The session consisted of three papers dealing with bio-
logical nitrification and one concerned with denitrification. All
four papers generated considerable debate, particularly concerning
experimental design procedures and data analysis.
Paper No. 57 investigated the inhibitory influence of
nickel, cadmium, copper, zinc, phenol and trichlorophenol on nitri-
fying bacteria. Inhibitory concentrations were presented for each
of these materials. Unfortunately, however, the toxicity thres-
holds presented for the heavy metals were based on total cations
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concentrations added, rather than on the amount actually in solution.
Because of metal precipitation and complexation reactions, the
thresholds observed may have been due to solubility limitations
rather than to toxicity limitations.
Paper No. 59 presented useful pilot-scale results from
an up-flow fixed bed biological nitrification reactor and a simple
mathematical model for the system. These data could be very useful
for future designs. Most of the debate was concerned with the
authors' interpretation than an increased air/water ratio in the
reactor resulted in increased nitrification because of the greater
turbulence generated.
Paper No. 61 presented a pseudo-steady-state model of
nitrification in a partially submerged rotating biological con-
tactor. This was an extension of work previously published on
fully submerged RBCs. The model correlated well with results from
laboratory studies.
Paper No. 63 provided a very interesting experimental proof
that the pH in a denitrifying biofilm varies with depth due to a
buildup of bicarbonate and carbonate in the film. A model for the
pH profile in a denitrifying biofilm was also presented.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The papers in this session all dealt with biological
nitrification and denitrification, subjects which are being researched
intensively in the United States. Since all of these papers were
presented by researchers from Europe and Asia, as was most of the
discussion, they should be of great interest to American researchers
and engineers.
All four papers were concerned with fixed-film reactors,
whether for nitrification or denitrification. This is an area where
European researchers have much more experience than their American
counterparts because RBCs and upflow filters have been in use in
Europe for much longer than in the United States. The paper on
nitrification in up-flow fixed bed reactors is particularly timely
as several research projects of a related nature are now on-going
in the United States. The kinetic and dynamic models presented,
while possible oversimplified, provide relatively simple techniques
for predicting the performance of biological nitrification systems.
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I. SESSION
A. Day: Monday, March 29, 1982
Hall: C
Time: 11:45 a.m. to 5:35 p.m.
B. Theme of Session: Wastewater Impacts and Uses for
Water Supplies
II. REVIEWER
A. Name: Julian B. Andelman
B. Position and Affiliation: Professor of Water Chemistry
Graduate School of Public Health
University of Pittsburgh
Pittsburgh, PA 15261
III. DESCRIPTION OF SESSION PAPERS
A. Paper No. 3: "Development of Water Reclamation Technology
in South Africa," by A. J. Clayton,
L. R. J. van Vuuren and B. Roux (South Africa)
This paper reviewed major results of the operation of the
Stander wastewater reclamation plant (SRP), a research-demonstration
facility in Pretoria, South Africa, and operational modifications
which were incorporated into the wastewater reclamation (WRP) in
Windhoek, Namibia during 1976 and 1979. It also evaluated various
aspects of the development and operation of the Windhoek plant.
Over the ten-year period from 1970 to 1980, several modi-
fications of the SRP were instituted in response to such problems as
difficulty in the optimal control of breakpoint chlorination due to
diurnal and seasonal variations in ammonia concentrations, and
optimization of the economics of activated carbon absorption for
the removal of organics. High lime treatment (HLT) and ammonia
stripping (AS) were introduced at the SRP to deal with the widely
fluctuating ammonia levels in the biofilter humus tank effluent.
An equalization basin was also incorporated. The activated carbon
resin bed capacity was doubled because the fluctuating humus tank
effluent required uneconomically high quantities of powdered
activated carbon. When activated sludge effluent became available
at the SRP in 1975, it was shown that chemical coagulation could
substitute effectively for HLT, and Ab was no longer required.
Direct reuse of reclaimed wastewater for a public water
supply was implemented at Windhoek using the WRP I in October 1968.
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Early in 1971, as a result of increased loading, poor quality of
the maturation pond effluent led to the discontinuation of the
operation of the reclamation system. In 1972 the latter was
modified to incorporate HLS and AS and operated as WRP II. In
the period 1972 to 1979 production was frequently interrupted
due to rapid scaling in the ammonia stripping tower and problems
with other equipment. Effluent from a new activated sludge
treatment system became available in 1979 and was used along with
alum flocculation instead of HLT and AS in WRP III. During the
subsequent twelve-month period, there were 25 weeks of operating
time during which 5 x 1(P m3 of reclaimed water were produced,
constituting about 16% of the potable water supplied to the popu-
lation of one zone of the city.
It was stated that operation of the WRP III "presents
no difficulty and is far simpler than that of the former treatment
modes." There were higher increases in sulfate, chloride, total
dissolved solids, and total hardness in the final effluent than in
the WRP II, but these were judged to be acceptable. Levels of
microbiota, pathogenic or otherwise, were also considered acceptable
in all modes of reclamation.
The WRP III was more economical than previous modes.
Nevertheless, it is more expensive than existing supplies, but
cheaper than the cost of developing additional sources. Activated
carbon is its highest cost. Therefore, it is important that the
biological treatment process be operated efficiently to minimize
the load on activated carbon. It was concluded that the Windhoek
plant has proved the practical feasibility and absolute safety of
direct reclamation.
Heaton (U.S.A.), the invited discusser, noted his agree-
ment that it is more important to know the quality of water than
its history. In response to his question about public involvement
in reuse decisions. Clayton (South Africa) indicated that there
was no great negative reaction, and there has been some public
concern about insufficient utilization of treated wastewaters.
Heaton (U.S.A.) asked about future developments, and van Vuuren
(South Africa) indicated several were under study or development,
including use of ozone in conjunction with activated carbon, and
the integration of wastewater treatment and reclamation. The latter
would include first the removal of solids and coagulatables, then
biological treatment, and finally physico-chemical processes. It
was emphasized that at Windhoek there is a fairly effective separa-
tion of domestic and industrial wastes, and this is an important
factor in the selection of a system to supply potable water.
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In response to a question about the maximum fraction of
renovated water mixed with conventional sources that might be used,
Clayton (South Africa) indicated that there is no reason why it could
not be 100 percent. He noted that at Windhoek in WRP III, for one
month one area was receiving about 70% reclaimed water with an average
of 34% for one year.
Wachs (Israel) indicated that in Israel, prior to reuse,
renovated wastewater is stored in aquifers following intensive
treatment. The advantages are that the storage phase helps public
acceptance and also provides an important time period for monitoring
to detect any potentially harmful constituents. In response Clayton
(South Africa) noted that a fish biomonitoring system is being in-
stalled at Windhoek to assist in the early detection of toxicants.
B. Paper No. 6: "Removal of Potential Carcinogens and
Toxicants by Treatment Systems for Direct
and Indirect Reuse of Wastewater Evaluated
by Means of a Hamster Cell Culture Assay,"
by R. Kfir and 0. W. Prozesky (South Africa)
This study used a mammalian cell transformation assay to
test for potential carcinogens and toxicants in wastewater reclaimed
for potable purposes, as well as in wastewater samples at various
stages prior to the finished water. It compared direct and indirect
reuse systems studied in April through July 1980. The direct reuse
system was that a Windhoek in Namibia, described previously by
Clayton et al. and referred to there as WRP III. The indirect reuse
system used water from the Rietvlei Dam which has been an auxiliary
source of potable water for the city of Pretoria, South Africa,
since 1933. The Hennops River, which flows into the reservoir,
receives secondary sewage effluent from an industrial community with
two treatment plants 15- and 25-km upstream from the dam. A very
high proportion ot the flow to the reservoir consisted of effluent
from these plants.
The water samples were analyzed directly following fil-
tration through a 0.22 pm membrane filter. Hamster cells were used
in the transformation assays when the cultures were three to six
days old. Using a media made with the water test sample, and
following an eight-day incubation, percent transformation and percent
survival was determined by counting colonies, with benzo-a-pyrene
as a positive control.
Both the direct and indirect reuse systems were found to
reduce the toxic and transforming activity of the water to low
levels. In both systems the percent transformation of the finished
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water was lower on each test date than samples at earlier stages
of treatment or, in the case of the indirect system, than upstream
samples. However, data were not presented for the finished direct
system water from WRP III, but only after it was mixed with con-
ventionally treated water. For the direct system, the percent
survival for the finished water was sometimes lower than at previous
stages of treatment, and even lower than that of the benzo-a-pyrene
positive controls. For the indirect system the percent survival
for the finished water was the highest on each sampling day although
sometime marginally so. No clear correlation was found between
chlorine levels and toxic or transforming activity for both reclaimed
waters.
It was concluded that for water samples in which there
was no correlation between levels of toxicity and transformation,
these two activities were probably due to different substances in
the water. It was judged that the finished water from the indirect
reuse system was of slightly better quality than that of the direct
one. Referring to another study, it was noted that fewer potential
carcinogens and toxicants were present in both systems than were
found previously in a good quality drinking water.
The invited discusser, Andelman (U.S.A.), noted that the
approach of comparing the toxicity of various waters was useful
and asked what evaluative role this test system could play in con-
junction with others. Prozesky stated that a battery of living
organisms should be used to evaluate potential human health effects,
but that such analyses are expensive and complex and, therefore,
should best be used to assess a reuse system and its optimal opera-
tion, rather than for frequent testing of individual samples. In
response to questions by Andelman on the inherent variability of
the method, and also why they did not concentrate their samples,
Prozesky replied that they did not have the opportunity yet to measure
reproducibility; also that they did not concentrate the samples so
as not to increase cell toxicity to undesirable levels, and also to
avoid the problems of introducing artifacts and selecting for some
constituents at the expense of others.
Best (South Africa) called attention to statements that
in the direct reuse system, the carbon filter often did not reduce
and even increased toxicity and transforming capacity and asked if
that might indicate that the carbon filter was adding or producing
toxicants under some conditions. The author replied that at least
on one day when this occurred, the carbon columns were overloaded,
were being adjusted, and the product water was not being used.
Englande (U.S.A.) commented that his studies were also
using a mammalian cell culture test system and that they were
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concentrating by a factor of one-thousand by lyophilization; also
they were compositing samples throughout the day to minimize peak
responses. Van Rensburg (South Africa) noted that renovation system
studies involving spiking with knownorganic chemicals indicated
that a large number of these compounds were broken down by chlorina-
tion. It was indicated that this could influence the mammalian
system test results which showed that following chlorination and
sand filtration, the level of toxicants and potential carcinogens
in the finished water was usually reduced in the direct reuse system.
C. Paper No. 9: "Organic Micropollution of Potable Water
Supplies: Indirect versus Direct Reuse,"
by J. F. J. van Rensburg, S. J. Theron,
A. J. Hassett and P. G. van Rossum (South
Africa)
Organic chemical and other water quality parameters in
indirect and direct wastewater reclamation systems used for public
water supplies in South Africa and Namibia were compared. The
systems were the same ones described by Kfir and Prozesky (Paper
No. 6). The Windhoek direct-reuse system was sampled for a period
between two activated carbon cycles, while the indirect Rietvlei
Dam system sampling period was from late summer through early fall.
The organic chemical constituents studied included six
categories or groups of chemicals: volatile halogenated hydrocarbons
(VHH), i.e., trihalomethanes; chlorinated hydrocarbons and pesti-
cides (CHP); chlorophenols (CPHEN); polynuclear aromatic hydrocar-
bons (PAH); phenolic compounds (PHEN); and other compounds (DIV),
such as dibutylphthalate and nitrotoluene. Lower hazard limits,
either 0.1 or 1.0 pg/n, were specified for each compound, as were
organic pollution indices developed for various groupings of these
compounds according to their frequency found in various concentration
ranges. Other organic parameters measured were total organic carbon
(TOC), trihalomethane content of samples exposed to chlorine, and
UV absorbance at 275 nm. Fecal coliforms and two steroids were
measured as indicators of fecal contamination, and Ames ScubnonMa
tests were used to assess mutagenicity.
Based on a comparison of these various measured constituents,
finished chlorinated water of the direct-reuse Windhoek system was
judged to be of very high quality and better than that of the indirect
reuse system. The organic constituents in the Windhoek system, such
as VHH and TOC were not eliminated by the conventional water treat-
ment processes, but were considerably reduced following activated
carbon filtration. In comparison, finished indirect-reuse water
contained substantially greater quantities of organic constituents.
Also, some mutagenicity was detected in the latter effluent, but not
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in that from an experimental direct renovation system (i.e., the
Stander plant). Mutagenicity was not measured at the Windhoek plant.
It was concluded that the direct reuse system was preferable
to the indirect system because of its "multiple barriers" against
chemical pollutants and pathogenic organisms. It was noted that a
previous study had demonstrated that a direct water reclamation
system could cope with high loads of toxic chemicals.
DeWalle (U.S.A.), the invited discusser, emphasized that
the measurements indicated that the principal difference in quality
between the finished effluents of the direct and indirect reclama-
tion systems could be attributed to the use of activated carbon in
the former; and that, if it were used in the indirect system, the
two waters might very well be of equivalent quality. Van Rensburg
(South Africa) agreed and recommended that whenever indirect reuse was
practiced, serious attention should be directed to the possible
need to improve organic chemical quality by use of activated carbon
or other treatment processes.
Andelman (U.S.A.) and Shuval (Israel) raised questions
concerning the concentration levels found or the hazard limits
specified by the authors for trihalomethanes and other organics.
The author indicated that these limits were essentially targets
or warning levels, not precise health-related action levels. Shuval
(Israel) emphasized that when such compounds known to be mutagenic are
present, or mutagenicity tests are positive, as was found in the
indirect reuse finished water, sound water treatment technology
should be used to remove them. The author replied that some
caution should be exercised in the use and interpretation of such
tests in that increased sensitivities associated with high concen-
tration factors are likely to result in many waters being positive,
and thereby judged to be unsafe, when in fact their actual risk to
human health may be difficult to assess.
D. Paper No. 12: "The Economic Impact of an Urban and
Industrial Complex of Mineral Pollution
in the Water Supply--a Case Study," by
J. J. C. Heynike and S. F. McCulloch
(South Africa)
This case study was a cost estimate of the impacts of
projected mineralization of a storage basin (the lower "Barrage")
along a stretch of the Vaal River in a large (17,000 m?) area sur-
rounding Johannesburg, South Africa. This area has a population of
about 5 million and the mineralization is from gold mining and
urban-industrial development. Presently, about two-thirds of the
water supplied to the area is from the Barrage basin, and one-third
is from the upstream Vaal Dam impoundment.
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The present mineralization is mainly due to continuous
dewatering of gold mines, the dissolution of salts from mine rock
and sand dumps, and sewage and industrial wastes. The two
largest sources of dissolved solids were mine pumpage (25%) and
municipal sewage (14%). In 1979, the average total dissolved solids
(TDS) in the Barage was 660 mg/£. It was projected that without
action this could rise to an average of 1000 mg/£ by 1990, with
peaks of 1500 mg/£. The present annual average TDS in consumed
water (presumably from all sources) is 300 mg/£. It was estimated
that without further action this could rise to 500 to 800 mg11.
Projection of increased costs to the consumer as a result of or to
compensate for the increased mineralization was based on these two
values of TDS.
Examples of the types of costs that were considered
were: (a) household: impact on plumbing and increased use of
soap and detergent; (b) industry: treatment costs; and (c) water
supply authority: increased treatment costs and expansion of
reservoir capacity. Based on present charges to bulk water con-
sumers, it was estimated that the costs due to increase minerali-
zation would be an additional 100 to 150%.
Several courses of action were suggested to prevent
the increased mineralization. There were: (a) prevention of
mineralized effluents from entering the Barrage; (b) improvement
of water management techniques; (c) desalination and reuse of
effluents, and their disposal by evaporation or otherwise; and
(d) augmentation of raw water with other sources, although this
was considerd only a temporary measure.
Herold (South Africa), the invited discusser, noted
that the economic impact from TDS is an important new analysis
in that it emphasized non-public health effects of community
water supplies. He and the speaker indicated that additional costs
were not considered that could be important, such as the increased
sewer and sewage treatment costs, and the possible impact on
downstream agricultural users of the water. Another discusser
pointed out that a useful control strategy might be the collection
of high TDS effluents and their selective treatment. It was
emphasized that the main purpose of this study was to quantity costs
associated with increased mineralization so that it would aid in
decision-making on a variety of water supply projects under con-
sideration.
E. Paper No. 15: "Limnological Effects of the Elimination
of Phosphorus from the Wahnbach Reservoir,"
by H. Bernhardt and J. Clasen (Federal
Republic of Germany)
This study evaluated limnological effects of the Wahnback
Reservoir over a three-year period (1978-1980) following substantial
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reduction in phosphorus in the principal source of influent water,
i.e., the Wahnbach River. The reduction was achieved by treatment
of the river prior to its flow into the reservoir. The phosphorus
elimination plant (PEP) utilized precipitation, flocculation and
filtration to reduce the total phosphorus content (Ptot)
the effluent to 5 pgA, from an initial concentration of 100 to
150 yg/2..
7 3
The reservoir containing 4 x 10 m of water was used
for the drinking water supply of the city of Bonn and surrounding
communities. Beginning in 1957, eutrophication increased to the
point that large quantities of algae broke through the water
treatment filter, requiring additional flocculation. The growth
of diatoms and other algae caused shorter filter time runs and
a considerable decrease in treatment plant throughput. Other
associated problems included bad taste and odors, as well as inhi-
bition of the coagulation process by organic chemicals from the
algae.
Phosphorus compounds came from scattered communities and
farms as well as from erosion of agricultural areas. It was
decided that it would be more cost-effective to treat the river
effluent than to divert and treat the inputs to the river. Following
the institution of treatment, the reduction of phosphorus in the
river effluent began to affect the reservoir starting in 1978.
To judge the impact on the reservoir, P^0t criteria concentrations
were established to relate to its limnological state. These were
that there was an 80% probability that the reservoir would be
oligotrophic if the Pt0^ was less than 8 yg/Ji (volume-weighted,
annual average). The similar tolerable mesotrophic dose was 25 yg/£.
Based on these criteria, it was judged that the reservoir in
1979-80 was in a transitional phase between oligotrophic and meso-
trophic.
The phosphorus reduction in the river effluent to the
reservoir was about 90 percent. The average annual concentration
°"f Ptot in the reservoir itself were reduced considerably from
25-26 ug/£ in 1969-70 to 6 and 11 ug/d in 1979 and 1980, respectively.
There were also considerable reductions in biomass and chlorophyl1-a
concentrations, and the transparency of the reservoir improved as
well. There were changes in the types of algal species and their
seasonal frequency, with diatoms becoming predominant. It was
emphasized that the improvements were achieved by reducing phosphorus
only and were independent of the input of nitrogen from the river
(5 mg/d as an annual average).
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The invited discusser, Basalo (France), noted that
there were other instances in which the removal of phosphorus
has controlled eutrophication, but that the number of well-
documented cases was limited and may not yet permit generalization.
A few questions were raised by other discussers as to whether the
Wahnback situation was a special case, or whether its methodology
could be used elsewhere. The author replied that the ability to
practicably treat the single major source of the phosphorus was
the overriding factor.
In response to a question from Zunckel (South Africa)
about costs, the author indicated that it would have cost con-
siderably more to reduce phosphorus inputs at several other up-
stream points, and this would have eliminated only 70% of the
phosphorus. In reply to questions about the relative impact of
dissolved and suspended or sedimentary phosphorus on the eutro-
phication status, the author noted that there is still
phosphorus in the sediments of the reservoir. However, this is
now the principal phosphorus source and it is much lower w toto
now that the treatment process has been instituted.
IV. CRITIQUE OF SESSION
Papers No. 3, 6, and 9 from South Africa dealt with the
development and utilization of wastewater renovation technology
for potable reuse and the chemical and toxicological assessments
of the finished waters. They demonstrated the momentum and commit-
ment of the South Africans towards treated wastewater reuse for
potable water and the high state-of-the-art technology and science
they are bringing to bear in this field. One impression from the
discussions is that there is considerably more caution outside of
South Africa than in it about the speed or necessity for potable
reuse and the need to consider alternatives. One comment typified
the South African philosophy; namely, that they judge the measured
quality of the renovated water as being more important than its
history.
Paper No. 12, an assessment of the economic impact of
mineral pollution on public water supplies in an urban-industrial
area of South Africa, although an apparently competent study,
gave the impression of being a paper exercise dealing with impacts
whose numbers were quite "soft." It did not attract a lively
discussion.
Paper No. 15 on the effects of phosphorus elimination from
a reservoir used for a public water supply was a well-presented,
long-term study of an unusual approach to control eutrophication,
namely by treatment of a river effluent. The focus of several of
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the questions were on whether this was a unique situation that
lent itself to this approach. It appeared that the practicality
of the situation was of greater interest than the limnological
aspects.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Although research and development activities in the
United States on wastewater renovation for non-potable use have
been well underway for at least 20 years, similar efforts on
potable reuse have been much more modest, cautious and recent.
It does not appear that the technology and applied science in the
South African efforts are more advanced than in the United States
but that they feel the need and have proceeded rapidly in the
direction of potable reuse. The possible significance of this
South African work is that the demonstration of the practicality
of these systems, including public willingness to drink the
water, may help overcome the psychological barriers to potable
reuse here. Also, their approach in evaluating the finished
water rather than the nature of the raw source is at variance
with longstanding United States thinking. In this country,
it should be examined for its possible utility.
The paper on phosphorus removal from a river effluent
to a water supply reservoir to control eutrophication is signifi-
cant in its approach of not treating the sources to the river, but
the river itself. Where correspondingly efficacious hydrological
situations to control phosphorus or other chemicals may arise in
the United States; this example might serve as a stimulus to
examine river effluent treatment as a practicable alternative to
source control.
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I. SESSION
A. Day: Tuesday, March 30, 1982
Hall: C
Time: 9:00 a.m. to 12:30 p.m.
B. Theme of Workshop: "The Use of Mathematical Models"
(Theme 1)
Convenor: A. Gerber (South Africa)
Panelists:
II. REVIEWER
A. L. Gameson (United Kingdom),
J. L. Marivoet (Belgium),
T. 0. Barnwell (U.S.A.) and
A. James (United Kingdom)
A. Name: Philip J. W. Roberts
B. Position and Affiliation: Assistant Professor of
Civil Engineering
Georgia Institute of Technology
Atlanta, Georgia 30332
III. DESCRIPTION OF WORKSHOP PAPERS
A. Paper A: "Review and Background," by A. Gerber (South Africa)
The chairman opened the session with some
introductory remarks which were confined to answering the following
questions: (1) What is a model? (2) How is a model developed?
(3) Why are models practical tools? (4) How are models misused?
(5) What skills are required for successful modeling and what safe-
guards can be taken against their misapplication?
A mathematical model is a set of equations which, subject
to certain assumptions, describes the physical, chemical, or bio-
logical processes of interest in the water body. The body may be
a river, lake, estuary, coastal water strip, or groundwater. Model
development requires a four-step procedure. The first is to gain
an understanding of the system to be modeled. Second, the governing
relations identified in the first step are translated into mathema-
tical equations which approximate the behavior of and interrelation-
ships between the various water quality parameters being considered.
Third, a computational scheme is developed to solve the set of
equations. The fourth step entails validation of the model. This
attempts to make a general model unique to a particular water body,
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and also establishes the level of confidence in the model results.
The first part of validation is calibration which involves adjust-
ment of model coefficients until the computed results match those
from the historical behavior of the system. The second part of
validation is verification during which the model is tested against
several other independent data sets. If results compare favorably
with observed conditions,the model is considered verified.
There are several characteristics which make models
practical tools. First, they provide a means to solve extremely
complex water pollution or water quality problems and can give
information which is otherwise unobtainable. Water quality data
give only a synoptic view of the combined influences of all factors
affecting the system, and it may be impossible to predict water
quality conditions accurately with analysis of the statistical
properties of historical data alone. Second, the models are avail-
able to anyone in the water quality business. The tools are where
they belong: in the hands of those doing the local work where the
problem areas exist. Third, a numerical code and data are a means
to transfer information as to how a problem was solved.
Models are misused in many ways, three of which were
highlighted. First is overkill and selection of the wrong model,
second is inappropriate prediction, and third is misinterpretation.
The temntation to use the most sophisticated model is often due to
lack of input data, perhaps causing the investigator to feel that
what is lacking in data may be rectified by use of a sophisticated
model. One should be cautious of choosing a model with audience
impact or public relations in mind. An overly sophisticated model
is the wrong model, and one needs competence, not only to use
numerical models, but also to know when not to use them. Numerical
models are the most powerful tools available for solving water
quality problems, and the chief drawback of any powerful tool is
that even slight misuse can bring disastrous results. Many modelers
seem to believe that numerical models can be calibrated to predict
future water quality trends regardless of the input data. This
is false, as the ability of a model to duplicate past conditions does
not guarantee its ability to predict future ones. The success of a
calibration is directly proportional to the amount of reliable
input data and the skill of the modeler. Perhaps the worst possible
misuse is blind faith in model results. Calculations that contradict
normal intuition may be the result of data entry error, an error
in the program, or misapplication of a model to a situation for
which it was not designed. If interpretation of the model results
is not coupled with a conceptual understanding of the system under
study, the whole exercise becomes not only a waste of time and
money, but a threat to the profession in which it is applied. This
is borne out when managers make broad reaching decisions about their
water resources on the basis of poorly constructed and interpreted
models. And when administrators distinguish good water quality
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studies from bad by assuming that the former are those in which
the numerical models are employed. These actions can only produce
untenable studies and management programs, and the end result may
be a loss of confidence in both the modeler and his models. Models
do not eliminate the need for data gathering efforts. Practical
experience, judgment and common sense must be combined with the
speed and accessibility of modern computers.
Finally, what skills are required for successful modeling
and what steps can be taken to safeguard against misapplication?
The modeler should have a firm understanding of:
1. The hydraulics of the water body under study and
the factors influencing water movements;
2. The strengths and weaknesses of field data collection;
3. The theory of the chemical and biological processes
being modeled ;
4. The theory of numerical water quality models; and
5. The principles of sound scientific judgment.
As protection against the misapplication of water quality models,
the following points are offered:
1. Does the modeler have sufficient background in modeling
and the scientific discipline in which it is applied?
2. Is the proposed model compatible with the available data?
3. Is the proposed model compatible with the stated
project objectives?
4. Has the proposed model been thoroughly tested and
successfully applied to other field problems?
5. Have all the pertinent assumptions which limit the
model been clearly understood and stated?
6. Is the model application an integral part of any data
collection activity?
7. Are the predictions based on modeling a valid extra-
polation of historical data?
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B. Paper B: "Application to Estuarine and Coastal Waters,"
by A. L. Gameson (United Kingdom)
The principles underlying the mathematical modelling of
parameters of pollution in estuarine and coastal waters were out-
lined in non-mathematical terms. Attention was drawn to some of
the difficulties encountered—such as in assessing the inputs of
relevant substances, evaluating coefficients of transformation pro-
cesses, and ensuring that models can reasonably be used for pre-
dictive purposes. Two examples were given, one relating to dis-
solved oxygen in an estuary, the other to enteric bacteria in the
sea. The application of models to the formulation of pollution
control policies was reviewed.
Gameson (United Kingdom) initially stated the four terms
of reference given to him for preparation of his paper. They were:
(1) For the benefit of non-mathematically trained
participants, descriptive, rather than mathematical methods are
required to show how models are arrived at. Accordingly, there
are no equations in the paper.
(2) Application of models to show effects of discharges
at different points to varying load.
(3) Show how models can affect policy decision. This
proved to be a tricky assignment as it is generally difficult to
find what has been the influence of a mathematical model on policy
decisions. For instance., those seeing the simultaneous clean up
of the Thames estuary over the last three decades and the advances
in estuarine modeling that were made in the study of that estuary
may well be excused for thinking that the cleanup resulted from the
modeling. This is not so. No mathematical model was needed to show
that the gross pollution of the Thames was attributable to the fact
that almost all of London's sewage was discharged to the estuary
with no more than primary treatment. The Thames would have been
cleaned with no mathematical model even though the model is still
used to provide a scientific basis for control of Thames pollution.
(4) Authors are requested to prepare papers with an inter-
national scope.
The various stages between the mathematical modeling and
the formulation of pollution control policies were first outlined.
The first stage is mathematical representation of water movements
with a degree of accuracy sufficient for the ultimate purpose of
the model. Next is the choice of the pollution parameters to be
modeled. As perfection is unattainable, much of the art in modeling
lies in knowing which corners may be cut and conversely where more
experimental data are needed for the development of a scientific model.
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The model must be shown to work satisfactorily. This
requires that field data be used with inputs of all relevant sub-
stances, and that the water quality predictions and measurements
must agree. Discrepancies may be due to imperfections in the
mathematical representations of the process involved or to inade-
quacies in the field data. If field data are available for a wide
range of environmental conditions, it will generally be possible
to make satisfactory adjustments to tune the model to get an
acceptable fit. But if, as may well happen with limited field
data, the model is adjusted to give the right answers for the
wrong reasons, it may give entirely misleading answers when used
predictively. It is worth emphasizing that the predictive use
of models is almost invariably extrapolative. They may be required
for predicting the effects of new discharges, of altering the degree
of treatment and point of entry of existing discharges, or of
reducing the freshwater flow entering an estuary. For this reason,
it is essential that the model be adequately verified.
At this stage, publication generally ceases. The scientist's
work is done; he has shown that he has provided the authority with a
management tool. The literature on verified models is notably less
than that on unverified ones. In some cases the model is never applied
as the management decisions could not wait for the modeling or the
model is used to confirm the decisions already proposed or taken. In
other cases, it is used to predict the efficacy of various alternative
pollution control strategies, so that the most appropriate one can
be selected. The readily available literature on the application of
models is sparse. The concluding remarks on a number of papers indi-
cate that the model described has reached the stage at which it
provides planners with a means of assessing the effects of various
water control management strategies. The management decisions resulting
from the applications of models, however, are rarely published in
technical journals. The managing authority is responsible to whomever
funds it, but reports of its decision and the reasons for them will
generally have a limited circulation.
It is evident that estuarine water quality models are
extensively used in the United States, United Kingdom and Australia,
but coastal water quality models are not applied to the same extent.
Some models with wide range of applications to coastal and estuarine
models do exist.
Gameson (United Kingdom) referred to some problems encountered
with models with which he had been associated. There are problems
in representation. For example, a coastal model described assumed
that tidal currents run parallel to the shore and that the sea bed is
horizontal, and specification of boundary conditions is difficult. A
model need be no more complex than required by the use to which it is
to be put. For example, if an estuary is well mixed, a one-dimensional
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model will surface. Two-dimensional models may be needed if there
are marked variations in properties over the width or depth. The
most complex situations may require three-dimensional models
although the lack of adequate field data may obviate their use.
Finally, there is dispersion; its representation is more difficult
in the coastal than in the estuarine situation. Dye patches do not
spread out radially from their sources even in the absence of wind.
And the most suitable representation of diffusion will depend on
the length and time scales involved. Thus different representations
may be needed when considering a substance with a rapid rate of
transformation and one which is almost conservative. The appropriate
rate constants cannot always be readily evaluated, as is the case for
bacterial mortality in the sea.
Another problem area is that of input data. Adequate data
can readily be obtained for a single ocean outfall. There may be
several hundred potentially polluting discharges to a large estuary,
however, and sufficient data on these may be lacking. The chemist
is concerned with concentrations in the discharge, the modeler with
inflow rates. Diffuse sources are also uncertain: storm sewage
overflows and rivers cause uncertainties in coastal waters. The
effects of these on bathing waters are far greater than the same
loads when discharged from a long sea outfall.
The third problem area is that of water quality data. More
data are required for more complex models, and isolated intensive
surveys may be inadequate. First, because the model may give either
steady-state predictions which are unrelated to any particular survey
or do not extend long-enough. Second, the intensive survey may not
have the transformation rates assumed by the model. For example,
reaeration rates of estuaries can be substantially increased by a
strong wind, and the rate of bacterial die-off in the sea can be
increased by sunshine.
The final problem area is verification. This is essentially
a compounding of all of the previous problem areas discussed. Model
tuning may take months with the client already waiting for predictions.
An ideal time to stop may be when the sensitivity analysis, taking
account of all the possible model parameter uncertainties, shows that
the uncertainties in the predictions are unlikely to lead to the wrong
management decision. Although he likes this idea as a theoretical
concept, it may not be a practical one. Coarse tuning may be adequate
for a simple situation where the answers obtained are clear cut.
Finer tuning may be needed if the implications are not clear or if
the model is to be used for a variety of purposes.
Harold (South Africa) liked the emphasis on the need to
tailor the complexity of the model to the complexity of the problem
at hand, but wanted to make a strong case against oversimplification.
He cited an example of an estuarine model used to predict changes in
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a harbor at Richards Bay. The model was incredibly oversimplified.
The results were compared to those produced by a more complex
model and found to be off by 200% to 300%. On the other hand,
about a half million Rand were spent on a physical moving bed
model which was equally incapable of predicting the effects in
terms of tidal fluctuations.
C. Paper C: "Application to Rivers and Underground Waters,"
by J. L. Marivoet, F. De Smedt, A. Van der Beken,
J. Dirickx, and W. Van Craenenbroek (Belgium)
Mathematical models describing the water quality in rivers
and groundwaters are derived from mass balances. For rivers, a one-
dimensional transport equation is derived. Different methods of
parameter estimation are considered and more recent techniques are
introduced. For the application of water quality models to river
management, two groups of models are considered: simulation and
optimization models. As a case study, the Bedford Ouse quality models
were described. Practical and theoretical applications in the United
Kingdom, Canada, Federal Republic of Germany, United States of America
and Belgium were discussed. For groundwaters, several applications
of water quality transport models were discussed and their use in
groundwater management was explained.
Marivoet (Belgium) presented the paper and confined his
presentation to everything but groundwater applications. In intro-
ducing his paper, he referred to the use of mathematical models in
quickly comparing different water pollution control strategies.
The development of a one-dimensional river model was then
discussed. Two types of river modeling were distinguished:
mechanistic models and "black box" models. Mechanistic models try
to describe all the physical, chemical, and biological processes
occurring. Black box models are much simpler, giving linear
relations between inputs and outputs without attempting to describe
the internal processes. A third intermediate model type is a
"grey box" model, which is a black box model with some mechanistic
components.
As an application of a mechanistic model, a model pro-
posed by Knowles and Wakeford (1978) was discussed. This model
described dissolved oxygen, biochemical oxygen demand, ammonia, and
nitrate concentrations in a river. Eleven biological, chemical, or
physical processes were included. Twenty-five model parameters
are needed, many of which are difficult to estimate.
An example of the black box modeling technique proposed
by Whitehead (1975) for the Bedford Ouse in the United Kingdom was
discussed. This model described nitrate, dissolved oxygen, and
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biochemical oxygen demand. Just three rate constants and three
lumped parameters were required, which can be obtained by statis-
tical methods if a long-term series of water quality measurements
are available. For good results, however, time-dependent parameters
are needed, which can be obtained by techniques such as Kalman fil-
tering.
For short-term predictions, black or grey box models are
generally preferred. For long-term predictions, and particularly
if large river changes are proposed, mechanistic models are mainly
used.
A Belgian application of the use of models in decision
making was then presented, based on the work of Nihoul and Smitz
(1976), Nihoul (1979), and De Smedt, et al. (1981). The model was
used to predict the quality of water extracted from a river-canal
system in Antwerp. The river is polluted and does not satisfy
drinking water criteria at low flows. The model permitted the water
quality manager to decide on the use of water from storage reservoirs
or canals, based on predictions of water quality parameters for each
case. This is particularly useful during drought periods when the
reservoir water must be economically used.
Practical examples of river quality modeling were given
in the text from the United Kingdom, United States, Canada, and
Germany. After the text submission deadline, interesting reports
were received from Australia and the Netherlands.
Marivoet (Belgium) concluded that qreat restrictions were
placed on model use in decision making by the poor results obtained
with models that are improperly calibrated and tested. Confidence
limits on water quality predictions should also be stated to allow
the decision maker to account for uncertainties in predicted values.
Mathews (United Kingdom) noted that reference is made
to the work his authority (Anglian Water Authority) is doing on
river quality modeling. The main purpose of this work is to enable
calculation of permissible qualities for 1120 sewage works and
several hundred industrial dischargers in their authority.
To do this, the many uses of the river are defined and then
associated with allowable contaminant concentrations. Users are
assigned to each river stretch, and the most sensitive value of water
quality parameter for that use is selected. This then forms the
river quality specification to ensure that all the required and planned
uses of the river are protected. The model discussed in the text is
then used to translate the river quality specifications into per-
missible discharge limits. Practical applications and model develop-
ment have proceeded simultaneously, and the model predictions are
routinely used in planning.
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There is a problem with ranking of priority of discharge
problems, however. Therefore, a second, more subjective model was
developed to produce an "index of discharge impact." The higher
the index, the higher the priority of a scheme in the capital program.
The point he wished to make was that models can be and are used in
routine planning and in large-scale operations.
Briggs (United Kingdom) stated that his background was in
instrumentation and control rather than in mathematical modeling,
and as a consequence, he was probably more biased towards black
and grey box models used in real time. As a practical user of
models, he indicated the major reasons for model development
are to obtain a better understanding of the regime or process;
secondly, for day-to-day management purposes, for example, intake
protection or process control; and finally for general management
in real time, for example, flood warning. Models are also valuable
in design of water and wastewater treatment plants when the model
is not used on line and in planning for pollution control. In all
of these applications, the model is only useful if it can be applied
predictively, and the predictive precision depends on the degree
of validation. At all stages of model development there should
be continuing refining and tuning based on real-time data gathering
if possible, or by careful interfacing of laboratory data into the
model.
Because of recent advances in microelectronics, sensors,
and computers, it is now possible to do this at reasonable cost.
By a dual sensor approach it is possible to produce data of known
and adequate precision. Briggs (United Kingdom) cited a computer
control system in England which has operated for two years without
failure. The system cost was about $150,000, and its use obviated
the need to build a storage reservoir which would have cost more
than $4 million. Modeling is now being applied to the data collected
to control the treatment process.
Some details and results of instrumentation applications
were then discussed. A new development is to measure heats of
reactions by means of captive enzymes on thermistors, developed by
Mossback and Nielson in Lund, Sweden. Sensors are available for
detection of heavy metals, insecticides, cyanides and phenols.
The major point that Briggs (United Kingdom) made was
that if we can measure online, and with reliability, the variables
to which the model is most sensitive, then the model can be con-
tinually tuned and used predictively with much more confidence.
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D. Paper D: "The Use of Water Quality Models in Management
Decision Making," by T. 0. Barnwell, Jr., and
P. A. Krenkel (U.S.A.)
The use of water quality models in three management con-
texts is described: screening, planning, and design. Screening
models are illustrated by describing a methodology applicable to
large areas of land and another applied to a large number of
chemicals. The application of models in a planning context is
illustrated by a local planning agency's use in developing non-
point source control strategies and by the federal government's
use in assessing potential exposure to a pesticide. Development
of design criteria is illustrated by summarizing the long history
of model use to develop effluent limits in the Holston River basin
(Tennessee).
Screening models are fairly simple and quick to use;
they can often be implemented on hand calculators. They are
intended to be conservative, and only to indicate potential pollu-
tion problems which should possibly be pursued further. Typical
model designs for streams and rivers, lakes, and estuaries were
discussed and the results of two applications, to the Sandusky River
basin and the Chesapeake Bay watershed, were presented.
Planning models are more sophisticated and require con-
siderably more effort to apply. Two examples of their use were
presented. The first was to design pollution control strategies
for the Occoquan River basin for the next 25 years. The second was
to investigate potential risks to aquatic life of use of a pesticide
in the Yazoo River basin. The results were used in negotiations
between the U.S. Environmental Protection Agency and the pesticide
manufacturer to change labeling instructions on the pesticide on
how the farmers should apply it.
The planning model applications demonstrated two strategies.
First, in the Occoquan, the modeling had an extensive data base,
and the model was thoroughly verified. Second, in the Yazoo, the
model was used to make estimates which would not otherwise be
available, to demonstrate potential effects.
Design model use is probably the most common application
of models in the United States. Typically, this would be to set
discharge requirements to meet water quality standards. An applica-
tion for the "seriously polluted" Holston River was discussed as
an example. The model was used to investigate the effects of a
wide range of management decisions. In hindsight, Barnwell felt
that probably the same conclusions would have been drawn without
the model use. Field studies showed that water quality was being
protected, and the model showed that little more improvement could
be gained from further treatment improvements.
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The conclusions were that models were effective tools
in screening, planning, and design. His experience was that
results should always be confirmed by data or some independent
analysis. Data is best, but not always available, so independent
analyses must sometimes be used. A thorough and objective review
should also be made.
Holden (Australia) said that it has been stressed that
quite detailed data must be available in order that models be
verified, otherwise users would doubt that the models are satis-
factory. He wondered if Barnwell (U.S.A.) would comment on this with
regard to this screening model. He noted that the rate of trans-
port of the chemical through groundwater was assumed to be limited
by the hydraulic conductivity of the soil and not by mass transport
through the boundaries of the containment facilities; that soil
sorptive capacity had been reached; steady-state concentration
profiles had been achieved, and hydrolysis was the only degradation
process considered in the groundwater. Does this mean that when
applying the model to each chemical, one must go out and measure
the hydraulic characteristics of the soils and assume that the soil
is uniform? Does it also mean that biological degradation is
neglected within the soil, and is it correct to assume that the only
degradation process is hydrolysis? He would assume that many of
the chemicals are not hydrolyzed at all. So it seems that there
are a tremendous number of assumptions built into the model.
Although bearing in mind that it is only a screening model, he
would nevertheless be interested to know if data have been accumulated
to see if the predictions are realistic. He would have grave doubts
on this.
In response, Barnwell (U.S.A.) said that they had to assess
many chemicals in a very short time. They did not neglect microbial
degradation in groundwater; there was evidence that the microbial
populations were very small. At that time, the main issue to be
addressed was whether the chemical would be transported through
the groundwater. It was felt that over a long time, because the
groundwater movement rates were very slow, that it would take a
very long time for a chemical to migrate even a hundred meters.
So that either a chemical migrated or it did not. If a chemical
hydrolyzed, the reaction rates were generally sufficient to degrade
it. If it did not, it would move into the river.
A sensitivity analysis was performed to see if the model
was sensitive to different movement rates and it was not. In cer-
tain cases, the chemical would degrade but not hydrolyze. The
assessment was designed to be conservative. If there was a poten-
tial problem, they wanted to predict it. Sometimes the models fail
totally, and the results must be viewed skeptically. The analysis
did not end there as they were trying to identify chemicals for which
additional data was needed; they cannot economically collect data for
every situation.
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E. Paper E: "Mathematical Modelling of Estuaries and
Coastal Waters," A. James (United Kingdom)
The paper was concerned mainly with the modeling of
physical aspects, but his presentation was more oriented to chemical
and biological aspects. An estuarine system has physical hydraulic
characteristics and is subject to waste loads. Together these con-
stitute the decay system, which interact with the reaeratlon system
to determine the level of dissolved oxygen in the estuary. Normal
estuary models take these two inputs and predict oxygen levels.
The oxygen consumption rate is pseudo-first-order, whose rate
is determined by the organic matter concentration in the water.
Reaeration is determined by the saturation deficit and is rarely
directly measured. The decay is also usually assumed to be homo-
geneous throughout the water column. In the Tyne estuary, however,
less than half of the 114 tons of ultimate oxygen demand discharged
daily remains in solution or suspension, and the rest settles on the
bed. It exerts an oxygen demand in a different way than if it
remained in suspension. These two demands need to be considered
separately in order to make a predictive model.
The nitrogen cycle was then considered as this can impinge
on the oxygen regime in two ways. In an aerobic situation, discharged
ammonia may be converted to nitrate in the water column or bed. If
we are trying to predict oxygen levels due to waste load reductions,
the kinetics of nitrogenous oxygen demand must be included, as this
could become the dominant future oxygen demand. This is not always
the case., but current understanding is sufficient to include nitri-
fication and nitrification kinetics should be included. Few models
can predict conditions in anaerobic estuaries, but, as this situation
often occurs, this would be a profitable area for increasing modeling
capability.
Another oxygen sink is connected with plankton. From the
modelers point of view it is fortunate that there are very few
things living there. Plankton can be significant, however, and
not much is known about their dynamics in estuaries, which, although
complex, may sometimes need to be included.
Although estuaries and coastal waters are lumped together
by modelers, their similarities are at best superficial. The varying
salinities in estuaries makes the development of significant popula-
tions difficult, a situation which does not arise in coastal waters.
In coastal waters, dissolved oxygen is usually not of interest, due
to the mcuh better dispersion and dilution. So coastal models should
be completely separate from estuarine. Coastal models are more con-
cerned with amenity and secondly with bacterial concentration. The
gap is felt to be the concentration on pipelines. The principal
pathway of wastes into the sea is by means of estuaries, and it is
surprising that there is not more modeling work concerned with dis-
persion from estuaries.
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In predicting bacterial concentrations, initial dilu-
tion, gravitational plume spreading, subsequent dispersion due to
wind, tidal currents and residual currents, and also die off must
be included. Only limited success has been achieved in attempts
to model this combination. Die off is much less understood than
is initial dilution.
Ecological models are less developed than engineering
ones, but help our understanding of the interactions and have a
useful role to play. Briggs (United Kingdom), the official discusser,
said that the main difficulty is in validating the models, yet it
is essential to verify the mathematical models by field work.
If not, we lose credibility.
There are two model types: (1) A piiosU, which are
models established intuitively and by common sense, but which are
often wrong; and (2) Scientific models based on measurements. In
showing how much we must be very careful with a. pfUoii models, he
related a story of an economics model used 30 years ago. The
problem was to dispense credit to different municipalities. The
model used 30 parameters, all of which added to zero, and so every-
one was happy with the money distribution as everyone got the same
amount. The model merely verified this. The message is to use
scientific models but to verify the approach independently.
Kuznia (Federal Republic of Germany) pointed out the use of
models for on-line control. The model can resemble the plant to be con-
trolled, and, if feedback is added, stability can be ensured. For
example, they made a nonlinear model for dissolved oxygen control
simulation in aeration basins. The benefit of this procedure was
that they very quickly and efficiently came to the correct coeffi-
cients for control, which were much better than the normal propor-
tional differential controls. He felt that simple models and
models which can be simulated first for control should be con-
sidered before putting a control into effect.
Alexander (South Africa) got the impression that, inter-
nationally, models are custom built. Most modelers feel it is easier
to build their own model than use an existing one. The state-of-the-
art in South Africa is that there are some good rainfall runoff
models, well documented and used. There are some recently developed
rainfall runoff salinity models, and rainfall runoff salinity economic
models are needed for evaluation of management options. For research
problems, they look at a suite of models and choose the most appro-
priate one. Examples are to determine the effects of weather modi-
fication on runoff and on eutrophication above dams. He added a basic
message: If models are used for management decisions, then it is
imperative that the user agency be involved in the model development.
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Gerber (South Africa) agreed that ideally technical experts
trained in the use of models should be a part of the management or-
ganization responsible for solving the problems to which the model is
applied. There is then a great incentive for the expert to use the
model properly.
Gerber (South Africa) commented on communication problems
between management and technical personnel which is a widespread
source of difficulties in model applications. The first problem is model
credibility: the lack of confidence of managers in models as decision
making tools. This may be because modeling is becoming increasingly
sophisticated and has developed rapidly. Many managers are unfamiliar
with modeling techniques and have no feel for applications to their
particular problems. While managers do not need to know all the
technical model details3 they do need some appreciation of the
framework and inherent limitations and assumptions of the models.
This may lead to initial uncritical enthusiasm which can lead to
disillusionment and mistrust. The manager may think that models
are mysterious and even threatening to his job.
The fault may also be with the professionals who build
and apply models. In particular, overselling of models and over-
modelling: e.g., the application of a model too sophisticated for
the job at hand. These can both lead to managerial disillusionment,
and to the impression that models do not produce efficient reliable
results for decision-making purposes. The output must also be
presented in meaningful way, and the uncertainties should be presented.
Graphics and other displays might be very useful. The modeler
must be attentive to managerial needs, and avoid jargon such as
dispersion coefficients which are meaningless to the manager. Interac-
tive participation between managers and modelers at all stages is
highly desirable.
Briggs (United Kingdom) replied to Gerber (South Africa) from
the water treatment facility standpoint. One reason that models are not
more applied is that the nature of the decision-making process is an
imprecise one. What one would have to do is convince the manager
that if he had more and better quantified data in front of him, his
decision making would be less imprecise. Second, there seems to
be a boundary between those people managing the facility, and those who
might suffer from a mismanaged facility. If there was a subjective
table to tell the manager what would happen, for example, if so
many tons of BOD went out on Tuesday at 2 p.m. instead of spread
over Wednesday and Thursday. And if he knew what storms or toxicants
were approaching his works, it would be relatively simple to make
decisions such as: should I accept this sewage straight into my
primary tanks and if I do will I run the risk of killing the bacteria
in the aeration basins, should I step feed and put that material
elsewhere, and should I pull the sludge back out of the settler into
the aeration tank front end to protect the sludge. If we model all
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these things, we can make short-term gains to attack acute diffi-
culties, but seldom make an overall gain in total performance. That
use of modeling is not pushed as well as it might be.
Garber (South Africa) stated a problem exists with accessi-
bility of models to users. He wondered whether top priority should be
given to making existing models more accessible. This would entail
improving the quality of information on models and making this
information and the models more available but also in improving
the training of those using the models. He wished to highlight
two areas: documentation and distribution.
Proper documentation means a model description, a listing
of the code, and a users manual. Documentation is not typically
listed in a consistent format and is scattered throughout the
literature. Consequently* people wishing to use models are often
not aware of what models are available nor where to find this
information. Documentation should provide an easy means for any-
one to run the model, yet this is not usually the case. The reason
for this may be that this is the last step in modeling, and often
not immediately necessary. Funds may be exhausted at this time,
and there may be little training or interest of the modeler in
preparing this documentation. There may also be little incentive
for him to document, and he may be reluctant to expose particular
features, uncertainties and assumptions in his model.
It is not in the interest of private firms to distribute
work developed for clients. Universities often develop the poorest
documentaton. Perhaps a prerequisite to funding by an agency should
be adequate documentation of the model produced.
Concerning model distribution, Gerber (South Africa) felt
a well documented model should be publicized and distributed to be of
value. There is no presently available service to coordinate this.
It seems necessary to provide a control facility, or clearing house,
which would be responsible for collecting information on models and
to actively engage in a program to make this information available
to users. This should be on an international basis as model develop-
ment is expensive, and unnecessary duplication of effort could be
avoided. This is particularly needed by developing nations which
have no modeling expertise of their own.
Barnwell (U.S.A.) responded to Gerber (South Africa) by
saying that a report responding to many of his concerns in terms
of model accessibility and user training was about to be published.
An organization has been formed, called the center for Water Quality
Modeling, to provide documentation and code for a limited number of
models. A users group also exists which has a mailing list of about
1000 people. If anyone wishes to be added, they should contact
T. Barnwell, U.S. EPA, Athens, Georgia, U.S.A.
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IV. CRITIQUE OF SESSION
The session contained more generalities than specifics,
and it is doubtful that the "state-of-the-art" was adequately
represented as many recent developments were omitted. Discussion
of the role of models in decision making was also sparse, although
this is probably due to the difficulty in finding out just what
the role of a model was in a particular instance. The value of
the session probably lies in the compilation of the many references
of the papers, but particularly in the discussion of modeling pit-
falls and methods to avoid them.
Gerber (South Africa) expressed very well the pitfalls of
model misuses, communication problems between modelers and decision
makers, use of oversophisticated models, and need for adequate
verification. His discussion of these problems, the effects of
poor quality modeling on the profession, and steps to obviate them
should be read by everyone concerned with mathematical model use.
Many of his points were echoed by other authors, particularly
the need for adequate model verification by field data or independent
analyses.
It is apparent that models are now routinely used in some
decision-making processes. Most of these appear to be in rivers,
particularly "black box" models used in conjunction with real time
data collection for plant control. Mechanistic models are also used
to identify highest priority discharge problems or areas which should
be studied further. In some cases, however, the models played no
role in the decisions made; the decisions were made without them.
River models are most commonly used, followed by estuary
models, and, least of all, coastal models. Groundwater was not
extensively discussed and lakes not at all. Presumably, river models
are the most common because rivers are usually one dimensional and
easiest to model, and,therefore, the predictions are the most re-
liable. Models are unlikely to be extensively used in decision making
if their predictions are not reliable. It is worth mentioning that
some believe that two- and three-dimensional models are still in
the research stage, and even two-dimensional models can only some-
times give useful results when applied with care.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The use of models in decision making for solving U.S. water
pollution control problems could be enhanced by requiring that con-
fidence limits be stated along with model predictions; that the
appropriate model be used (i.e., not too complex or too simple); that
the user agency be included in model development; and that adequate
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model validation be proven. It is not obvious how this can be
done, but tightening the requirements of pollution control agencies
would help. Although this seems contradictory to the current mood
for less regulation, it will be necessary if modeling and the pro-
fession are to be credible in the future.
More research in the area of "black box" models with real-
time data would be desirable. It seems that presently these models
are more used in Europe than in the U.S. Research in modeling the
chemistry of anaerobic estuaries is also suggested. Finally,
establishment of a clearing house would aid in avoiding duplication
of effort and could provide a common pool of information.
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I. SESSION
Day: Tuesday, March 30, 1982
Hall: C
Time: 2:00 to 5:30 p.m.
Theme of Workshop: "Oil Pollution in Marine and
Freshwater Environments" (Theme 2)
Convener: N. King (United Kingdom)
Speakers: N. King (United Kingdom), A. D. Read
(United Kingdom), M. T. Westaway
(United Kingdom), K. Poppinghaus
(Federal Republic of Germany),
R. B. Clark (United Kingdom), and
F. Berne (France)
II. REVIEWER
A. Name: Lawrence H. Keith
A.
B.
B. Position and Affiliation:
III. DESCRIPTION OF WORKSHOP PAPERS
Chemistry Development Coordinator
Radian Corporation
Austin, TX
This session was a state-of-the-art workshop and the formal
papers presented were for the purpose of introducing a topic for
discussion. King (United Kingdom) gave a brief overview of the topic
area. This, in turn, was followed by presentations of Read (United
Kingdom), Westaway (United Kingdom), and Poppinghaus (Federal Republic
of Germany), after which discussions of those three presentations
were entertained. The last two presentations were made by Clark
(United Kingdom) and Berne (France), after which discussions of those
two presentations were entertained. Then all the topics were opened
to discussion. In the interest of clarity, discussions involving
each of the five topics are presented after major points of the
respective topics have been summarized.
Read (United Kingdom), in a paper entitled "Legal and
Administrative Control Aspects of Oil Pollution," discussed wide-
ranging aspects of both the international legal problems and the
various sources of oil pollution with their current pollution
control meaures. He focused on the often ignored but increasingly
significant problem of pollution from lubricating oils. He
estimated that about 1% of all petroleum production ends up as
various lubricating oils. Furthermore, half of these are not
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consumed and therefore ultimately must be disposed of. The problems
with trying to recover and recycle these oils are that they
(1) accumulate in relatively small amounts; (2) are widely distributed
and depots may be in remote areas; and (3) are contaminated with
numerous degradation products, preservatives and special additives.
The attempted solution to this problem in Germany is to subsidize
the collection costs; while in France it is to license the disposer
and to control the prices paid for these waste oils.
Rivas (South Africa) questioned whether the levels of at-
mospheric pollution would be increased by burning lubricating oils.
Read (United Kingdom) replied that increasing costs of oil makes the
burning of waste lubricating oils more attractive, and to help counter
this trend, Germany and France enacted the above-mentioned laws.
Westaway (United Kingdom) commented that significant contributions to
hydrocarbon emissions in air would occur only if oil combustion was
incomplete; a more important concern is the potential for heavy
metal pollution. The solution to one problem can therefore be the
cause of another problem.
With respect to the international law aspects of the paper
by Read (United Kingdom), the main concern of the audience was the
low probability of enforcement. He allowed this was true in open
seas but international and national laws can be enforced in harbors
and around offshore oil platforms. He suggested increasing the
percentage of ship logs versus cargo that are checked and preparing
"black lists" of offending vessels; segregated ballasts would also
help. Heynike (South Africa) asked who had responsibility for
treatment of ballast tank wastes. Read (United Kingdom) replied that
it was the obligation of each country to provide port treatment facili-
ties for ballast wastes. Furthermore, if the facilities are full and
cannot take the ballast waste or if there are no facilities for this, then
the oil tanker's liability ceases and it can dump the whole ballast
tank. This aspect of a nation's port liability is widely known.
About 50% of the countries that have oil tanker ports are ratifying
a 1978 international protocol and this should help the situation.
Of course, this still leaves half of the involved countries that
do not subscribe to minimum rules regarding oil pollution.
Westaway (United Kingdom), in a paper entitled "Sources
of Petroleum Hydrocarbon Inputs to the Marine Environment," listed
the most significant sources as natural seeps, offshore oil pro-
duction, marine transportation, coastal industrial effluents (in-
cluding but not restricted to refineries), the atmosphere, and
urban run-off. Most of these are point sources with the result
that the hydrocarbon inputs are unevenly distributed in the seas.
He also made the strong point that the environmental impact of
these inputs is not necessarily proportional to the amount of
hydrocarbon input to the oceans. Rather the environmental impact
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is dependent on several other factors including the location of
the discharge, the type and concentration of oil, and whether the
discharge is continuous.
Heynike (South Africa) requested more specific information
on sources of hydrocarbons from the atmosphere. Most of these
hydrocarbons are believed to result from unburned emissions from
vehicle exhausts. Lesser contributions may also come from volatili-
zation of hydrocarbons from gas stations, refineries and storage tanks.
Another significant source may be biogenic origins from trees and
plants. The mechanism of their input to the oceans is through
rain, dust particles and similar transport modes.
Poppinhaus (Federal Republic of Germany) presented a paper
by Luhr (Federal Republic of Germany) entitled "Economic Aspects of
Oil Pollution." Although cleanup costs associated with an oil
spill can be ultimately calculated with reasonable accuracy, costs
from destruction of the ecology of an area is almost impossible to
estimate. The latter is subjective and depends on differing eco-
nomics, geographical, hydrological and marine conditions. One
generalization that can be made, however, is that oil spillages on
the high seas cause less damage than those near shorelines. Another
generalization is that the bigger the oil tanker, the greater will
be the loss of oil in an accident. However, the frequency of acci-
dents is also less with bigger tanks than with smaller ones.
During the discussion period, the feeling expressed by
several was that supertankers were not desirable. However,
panel members pointed out that although the impact of
a supertanker accident was very large, their frequency was much
less. Given that most, if not all, transport accidents ultimately
are reduced to causes from human error, then it seems that the
only choice lies between fewer but greater accidents or many more
but relatively lesser ones. There was no consensus for either
unfortunate choice.
Clark (United Kingdom), in a presentation on "Biological
Effects of Oil Pollutants," made the point that often the reduction
in population of animal or plant species around a major oil spill
area is no greater than the natural fluctuations of some of these
species. Oil pollution from spills at sea so far has not permanently
reduced any plant or animal populations. Furthermore, the marine
environment is subject to wild and erratic natural fluctuations
of species populations. Therefore, these population dynamics must
be taken into account in assessing overall ecological damage. These
population dynamics also make it difficult to assess when ecological
recovery is "complete" in a spill area.
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One area, however, that does appear to be ecologically
sensitive to damage from oil spills is that of coral reefs.
Another question of ecological significance involves repeated
(chronic) spillages of oil in an area. These two aspects may be
more significant from lasting biological effects than the highly
publicized oil spills that involve the temporary demise of bio-
logical populations in limited areas.
The question of taste contamination of fish from chronic
pollution was raised. Clark (United Kingdom) replied that econo-
mically speaking, fear of tainting has a greater effect than the
actual tainting. Bartlett (South Africa) returned to the subject
of other biological systems besides coral reefs that are critically
sensitive to oil pollution. Clark (United Kingdom) felt that
another sensitive area consisted of the artic ecosystems which are
sensitive because of their very long recovery times. Loy pointed
out that another critical factor for biological recovery/repopula-
tion was the need for neighboring communities and that without their
presence, it would not occur. An additional factor that may be
critical is the absence of repetitive oil spills in an area attempting
to recover. Clark (United Kingdom) agreed with both statements and
pointed out that the Britany Coast is an example of an area being
seriously affected because of repeated oil spills.
Berne (France) presented the final paper entitled "Physical -
Chemical Methods of Treatment for Oil-Containing Effluents." The
basic principles and advantages/disadvantages of the use of cationic
polyelectrolytes, dissolved air flotation and various filtration
methods were summarized.
Tramier (France) raised the concern of adequate physical -
chemical treatment of offshore oil platform wastes. Berne (France) said
that dispersed oil flotation methods can reduce oil to about 200 ppm.
Emulsions, however, may be common problems because of abnormally
high suspended solids and cold water temperatures. Cationic poly-
electrolytes can be used with success with these oil wastes.
Harley (South Africa) requested some discussion on the
problems of removing oil from contaminated groundwater sources. Berne
(France) replied that aromatic hydrocarbons are always found as remaining
compounds in water contaminated by oil and that they can be efficiently
removed using activated carbon. Pentz (South Africa) commented that
a knowledge of the area hydrology is necessary because the best way
to treat contaminated groundwater usually is to pump it up, remove
the oil, and then pump it back. He also noted that in the United
States, bacterial growths have also been injected to remove oil by
metabolism.
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King (United Kingdom) closed the session with succinct
points from each presentation: (1) The primary concern of the
legal and administrative control aspects is to make existing
international agreements more effective; (2) in considering
sources of oil pollution, it is also important that its effects
be considered as well; (3) controversy still revolves around
whether it is best to use smaller (and more) tankers or large
(and fewer) supertankers with respect to economic and environ-
mental effects of accidents; (4) in considering the effects of
oil pollution, one must not underplay the effects of local
problems; and (5) available abatement technology for treatment is
still advancing and improving.
IV. CRITIQUE OF SESSION
Oil pollution in marine and freshwater environments con-
tinues to cause serious problems. In addition to the usual sources
of oil pollution, it appears that specialized refined oils will
become increasingly significant problems in spite of their relatively
low volumes.
Enforcement of existing regulations regarding oil pollu-
tion is sometimes difficult. Not all nations ascribe to these inter-
national laws and, among those that do, their enforcement is uneven.
This is sometimes caused by complications such as lack of equipment
in ports to handle spilled oils. There is probably a general lack
of understanding among most technical people for the economic and
legal complications that can beset the prevention and cleanup of
oil spills.
There is virtually no way that the economic aspects of
an oil spill can be estimated. Cleanup costs can be estimated
but not the costs associated with ecological damage. The latter
are not only difficult to find and quantify but are also usually
subjective. An ongoing controversy is whether it is better to use
smaller tankers and suffer from more oil spills because of increased
numbers of shipments or to use supertankers and suffer from fewer
but larger oil spills.
The natural population dynamics of species destroyed by
oil spills must be considered in order to keep incidents in proper
perspective. Public communications tend to focus on what appear
to be catastrophic destructions of species populations. Most of
these are able to recover within a few years except for Artie
populations, coral reefs ecosystems, and those subjected to multiple
insults.
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V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
One area where American technology can be brought to
bear is a greater understanding of pollution resulting from special
refined oils. Alternatives to dumping probably can be found that
will make collection and recovery of these oils viable. This is
a research area that has not received much attention in the past.
Research activities that make oil pollution cleanup
faster, easier and cheaper will gain acceptance and wide use.
Efforts to improve present technology could result in large future
benefits. Background studies on natural population dynamics and
the major contributors to speedy recovery of various ecosystem
species will be useful for evaluations and recovery plans when
dealing with future oil spills.
Physical-chemical recovery and cleanup methods still
need research to understand their mechanisms and to improve upon
their efficiency. Although this research has enjoyed significant
funding in the past, its fruits have justified additional funding
in the future in order to improve their cost effectiveness and
efficiency.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: C
Time: 9:00 a.m. to 12:30 p.m.
B. Theme of Workshop: "The Economics of Water Pollution
Control and Research" (Theme 3)
Convenor: G. Rincke (Federal Republic of
Germany)
Panelists: J. A. Lusher (South Africa),
G. Rohlich (U.S.A.), C. Lefrou (France),
K. Poppinghaus (Federal Republic of
Germany)
II. REVIEWER
A. Name: Carmen F. Guarino
B. Position and Affiliation: Past President, Water Pollution
Control Federation
Washington, D.C.
III. DESCRIPTION OF WORKSHOP PAPERS
A. Paper A: "Review and Background," by G. Rincke
(Federal Republic of Germany)
The subjects addressed were: (1) Why economize?;
(2) What methods are available?; and (3) How these methods can be
applied? To improve the decision-making process and to accentuate
the importance of water pollution control, it must be recognized
that cost reduction is not the only objective. There are other
important considerations such as the health factors and the social
usefulness of water resources.
B. Paper B: "Funding Water Pollution Control in South
Africa," by J. A. Lusher (South Africa)
A major portion of this paper dealt with the South African
Water Act. The objective of funding was to obtain the required
funds and to provide for properly qualified and trained personnel.
South Africa has been innovative, but more innovation is the key to
economy in the water and waste treatement field. Full use is not
being made of available data or the advantages of using computers.
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The matter of who pays is a complex issue and one should
refer to previous symposia in South Africa specifically dedicated
to this subject. The proper charge requires a complex formula and
should take the following into consideration: (1) What is fair
and who has the ability to pay? A study of the cost of charges
versus operational and capital costs in South Africa does not show
a proper balance; and (2) It is easier for local agencies or
government to increase a charge to industry? It is easy for
industry to add this cost to the products they produce. It is
much more difficult for local agencies and government to increase
costs of water and waste treatment to the local citizenry.
C. Paper C: "Funding Water Pollution Research," by G. Rohlich
(U.S.A.)
Because of the many factors involved in improving the
environment, it is difficult to determine the effectiveness of
money spent with accuracy. However, it is possible to make reasonable
estimates of funding of water pollution research.
Examining research funding from 1960 to 1975 shows a de-
crease by the United States government of 15%. During the same period,
United States industry increased their funding by 14%. Funding from
universities, colleges and other non-profit institutions which form a
small percentage of the total spent, has not changed appreciably
since 1960. Suprisingly, even though construction funding has in-
creased almost ten-fold since 1969 as compared with 1979, EPA funding,
the major agency responsible for research, has remained constant.
The National Research Council recommended that water quality
protection and control be given a high priority in federal research
programs. They specifically gave priority to the significance of
trace contaminants to human health, wastewater treatment research,
water purification research, improved analytical methods and detection,
enumeration of viruses and other infectious agents and monitoring of
chemical contamination.
The Federal Government of the United States, at the present
time, has been reducing their expenditures in research. This indi-
cates a need for research funding from other sources such as the
private sector.
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D. Paper D: "Balancing Benefits and Expenditures in Water
Pollution Control," by C. LeFrou (France)
Water pollution control is an economic necessity due to
the need for adequate water resources in urban and industrial
development areas. The economics of pollution control vary from
area to area depending on many factors, including, but not limited
to, demand and availability of resources. The cost per inhabitant
is reasonably constant. The building of a sewage treatment works
costs approximately 150 to 800 francs per inhabitant. The building
of a sewage network costs about 3500 francs per inhabitant and
individual sewage systems cost 300 francs per inhabitant.
The management of water resources and water pollution
control has many variables ranging from collection of data to the
management and execution of abatement programs. It is more economi-
cal to avoid pollution than to treat waste. Benefits to be con-
sidered are: fishing, swimming, boating, water fowl, hunting,
hiking, picnicing, camping, nature observation, health, household
benefits, industrial treatment costs, and commercial fisheries.
There are several methods used to evaluate benefits
from water pollution control, as follows: speculative, aggregate,
and methods applicable to particular sites. The speculative
method estimates benefits by the use of mathematical relationships.
The aggregate method uses statistical data coefficients to determine
benefits in large areas. The third method; that is, the method
applicable to a particular site, has its basis in surveys and polls
of the involved users.
A determination of benefits varies from country to
country, area to area, and site to site. There are many methods
and techniques. Choosing the best method involves careful and
extensive research and,finally, good judgment.
IV. CRITIQUE OF SESSION
In comparing funding problems, needs for funding, and
sources of funding from the different locations in the world, it
appears that the problem is somewhat the same; that is, none of
the agencies indicated that they had sufficient funding or that
they were able to devise a suitable, acceptable formula for obtaining
funding. Whether one discusses these problems with the worker in
Australia or in France, obtaining the necessary funding has been
difficult. What was not brought out in the papers was the basic
underlying reason for the difficulty in obtaining funding. Con-
sidering that people spend far more for less important resources,
there seems to be an undercurrent reasoning that clean water is
a God-given resource and:should be cheap.
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The papers focused on the essence of the meeting: the
state-of-the-art economy will be achieved by using the best avail-
able knowledge and properly qualified personnel.
There was considerable-controversy concerning the charging
for water and sewage services, not just based on use but ability to
pay. The ability to pay is further complicated by defining industry
as the most likely user to pay for needed funding.
It was also clear that cost/benefit calculations are
still difficult and, in the final analysis, require considerable
judgment in deciding which method to use. The South Africans, as
in many other areas of water resources work, have contributed
greatly to the study of economics in managing water resources, and
this information can be found in the symposia held in South Africa
over the last several years. It would have been useful to have
expenditures reported in the South African and French papers as
was reported in the United States paper.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
To begin with, the papers echo the funding problems that
are being experienced by the United States. It would have been
useful to know if there were federal subsidy and to what extent. This
would heln the United States, particularly at this time, since we
are struggling with the phase-out of the Construction Grant Program.
Observations in the foreign papers concerning who is to
pay and how much was interesting. The fact that some feel that
industry, since it has the means to pay, should bear a larger portion
of the expense of managing water resources is a case in point. If
the foreign papers reported the activities in the respective
countries accurately, then it appears that the federal government of
the United States does do considerable research.
Foreign papers did not uncover any new areas which were
unknown to United States researchers. The contribution of this
session was to obtain insight into the problems experienced by
foreign agencies and perhaps to obtain some comfort in seeing that
their problems are similar to those of this country. The papers,
in general, indicate that we must be more efficient, but this
efficiency, rather than coming from some major breakthrough, will
come from hard work by capable people using existing data and
knowledge. This,coupled with the research priorities recommended
by the United States National Research Council, goes a long way
towards outlining our work for the next several years.
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I. SESSION
A. Day: Thursday, April 1, 1982
Hall: C
Time: 2:00 to 5:30 p.m.
B. Theme of Workshop: "Technology Transfer" (Theme 4)
Convenor: S. H. Eberle (Federal Republic of Germany)
Panelists: J. Sidwick (United Kingdom),
C. Guarino (U.S.A.),
P. E. Odendaal (South Africa),
M. J. Pieterse (South Africa),
J.Bernard (France)
II. REVIEWER
A. Name: Aharon Netzer
B. Position and Affiliation:
III. DESCRIPTION OF WORKSHOP PAPERS
Professor of Water and Wastewater
Engineering and Environmental
Sciences
The University of Texas at Dallas
Richardson, TX 75080
A. Paper A: "Review and Background," by S. H. Eberle
(Federal Republic of Germany)
Eberle (Federal Republic of Germany) gave the introduction
and the opening remarks to the session. In his opinion, one of the
most important problems in wastewater process design is scaling,
both scaling up and scaling down. The problem of scaling is not new
and engineers all over the world have struggled with it. With present
advances of wastewater engineering, most plant and research engineers
cannot handle all technical aspects of process scaling and need the
help of an expert.
A great deal of technology transfer is needed in order to
comply with new problems in wastewater treatment and the development
of new technologies. The logical approach to solve current scaling
problems in wastewater engineering is first to define the problem,
then to search the literature for possible solutions, and when all
the available information is on hand to select the most appropriate
technology. The next steps are laboratory-scale experiments, then
pilot-plant scale experiments, followed by construction and operation
of a demonstration plant including cost evaluation. Only after that
should full-scale plant operations be implemented.
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The author gave details of manpower, money and time frame
involved in each state. In Germany, it takes from five to seven
years from the definition of the problem through the stages of
literature survey, identification of possible solution, laboratory-
scale experiments, pilot-plant scale experiments, demonstration
plant and implementaton of the solution with full-scale operations.
B. Paper B: "Scale-Up Problems," by J. Sidwick
(United Kingdom)
Sidwick (United Kingdom) discussed problems of scale up of
wastewater treatment processes from bench-scale to pilot-scale
and from pilot-scale to full-scale. In his opinion one of the main
problems in scale up is "technology transfer." From the research
laboratory to the full-scale operating plant there are a lot of
steps which are usually taken by a number of people. We not only
have the problems of transferring the technology itself through
these various stages, we also have the problem of insuring that the
knowledge acquired at each stage is fully passed on to those under-
taking the next stage. Therefore, "scale-up" is both a human
communication transfer problem and a technical transfer problem.
Scale up can start with the researcher who has a good
idea and who develops it in a simple way in a test tube and later
in bench-scale work. The scientist will probably publish his
results. If his work looks promising, he is likely to build
bench-scale pilot plant equipment in order to simulate more realis-
tically the full-scale situation. Assuming that his work has been
successful, he will have published his findings. If the findings
meet a need, then practical engineers or operators will take them
and apply them. Usually this application will first be on a larger
pilot-scale. Sometimes, modifications are made to an existing
full-scale plant to allow it to be operated experimentally. This
second stage of development may, or may not, involve the original
researcher. Finally, the process may be accepted as being valid
and may be widely introduced on full-scale. The process has to be
proven, refined and shown to be practical in real situations with
real operators. There is an absolute need to insure that findings
established in each stage are communicated in full to the next
stage. Sidwick (United Kingdom) encouraged the scale-up engineer
to maintain close liaison and to consult with the original researcher
and the operators who can spot difficulties and suggest solutions.
Sidwick (United Kingdom) referred the audience
to his paper for more information about pilot-plant scale proving of
process design, pilot-plant scale operation to demonstrate process
suitability, pilot-plant scale operations to allow full-scale cost
estimate, mathematical modeling and its role in scale up and real
life problems to try to put scale up into perspective technically.
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Sidwick (United Kingdom) concluded from his paper that:
(1) the researcher working at his bench to produce academic and
theoretical explanations of why things happen can offer the key
that will unlock the door of the more pragmatic; (2) the bench
scale work of the researcher can often not be scaled-up with the
reliability often implied; (3) bench-scale plants usually need
to be developed into a reasonable pilot scale to simulate the full
scale; and then it does not always simulate properly; (4) in the
final analysis nothing is as good as full-scale operation and, often,
the interpretation of less-than-scale work is heavily influenced
by full-scale operational experience; and finally, (5) the researcher
generates the concepts that may or may not work in practice: the
designer and the operator will see if they do and will learn much
more about the mechanisms of the process.
Scale up problems can be considerable, but the blurred
transition from bench-scale, to pilot-plant, to full-scale is
inherent in the logical development of processes from academic
aspiration to operational reality.
There was only one comment from the floor by Bricks
(United Kingdom) about the "not invented here syndrome." Bricks
(United Kingdom) agreed with the need for information to be
totally transferred at each stage during technology transfer, but
asked, "What do you do with the block that occasionally occurred
with the recipient?" Bricks (United Kingdom) gave an example of
'the lack of communication between industry and consultants in England.
Sidwick (United Kingdom) agreed that this is a serious lack of com-
munication which costs the public a lot of money unnecessarily.
C. Paper C: "The Role of Consultants," by W. Eckenfelder
(U.S.A.); presented by C. Guarino
(U.S.A.)
In consideration of the role of consultants in technology
transfer, it is important to consider two separate cases, municipal
water pollution control and industrial water pollution control.
The industrial case would consider industrial wastewater works
with large industrial inputs. It is not feasible to apply results
obtained for biological treatment of municipal wastewater to most
industrial categories. Technology transfer needs to be restricted
to wastewaters of similar chemical composition.
With respect to nitrification, the large amount of data
presently available for municipal wastewater treatment plants
permits technology transfer from one situation to another with a
high degree of confidence. In the case of industrial wastewaters,
inhibition frequently exists, calling for process design modification.
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In the case of sludge handling and disposal, technology
transfer must be very carefully applied, considering the nature
and characteristics of sludges to be handled (municipal or industrial).
Priority pollutants is a new dimension that entered the
water pollution control field over the past few years. In many
cases conventional wastewater treatment technology is not able to
remove these pollutants and innovative approaches are necessary.
Technology transfer in this case is primarily drawn from experience
in the chemical process industries.
Many of the technologies developed in the late 19601s
and early 1970's were energy intensive. The trend today in the
United States and many other nations, is to sacrifice some per-
formance efficiency for economics due to increased energy costs and
chemical and material costs. While Eckenfelder (U.S.A.) applauded this
approach as being realistic in light of present economic conditions,
he stated that consultants must exercise caution in the application
of technology transfer with existing data. Many of the more recent
technologies are specific for certain types of wastewaters, and the
transfer of technology should involve a carefully planned and
executed pilot plant or laboratory study. It is critical for the
consultant to develop design parameters through appropriate pilot
plants or laboratory studies and only employ technology transfer
for similar wastewater characteristics.
Guarino (U.S.A.) complimented Eckenfelder for being one of the
first and few scientists in the United States to promote the idea
of "custom treatment": relying on laboratory and pilot-plant
studies results instead of design parameters from textbooks.
Guarino (U.S.A.) stated most consulting engineers prefer
to follow existing plant design and are reluctant to implement
innovative technology. Usually the client must insist in order to
Implement innovative technology in his project. The U.S. Environ-
mental Protection Agency (EPA) recognized the gap in technoloqy
transfer and implementation of innovative technology. Therefore,
The U.S. EPA allocated special monies to fund projects involving
innovative technology, but then "red-tape" restrictions made it
very difficult to get grants for innovative technology.
Guarino (U.S.A.) mentioned we have not done much since the
discovery of the activated sludge process in 1913 and that there
is a lot more we can do. It was reported that 60% or more of the
wastewater treatment plants in the United States built by public
funding are not meeting permit requirements. Guarino (U.S.A.) said
that we needed to have technology transfer so every engineer would
know how to design a wastewater treatment plant.
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Todo (Australia) commented from the floor that if one
develops a successful innovative technology for a client, it is
often that the client does not wish that this technology be trans-
ferred to his competitors and does not want to publish the results.
D. Paper D: "Involving Practitioners in Research - A
Key to Successful Technology Transfer,"
by P. E. Odendaal (South Africa)
Odendaal (South Africa) defined technology transfer as the
application of research findings, i.e., closing the gap between re-
search and development. In the literature there is lack of common
theory underlying the technology transfer process. This is an indi-
cation of the complex nature of technology transfer which is, in
fact, not a single process but the end result of many processes
which vary from case to case.
The author indicated the prerequisite for successful
technology transfer is personal contact. Many of the standard
techniques for technology transfer such as various forms of publica-
tions, conferences, seminars, films and demonstrations offer limited
opportunities for personal contact and therefore mainly serve to
create awareness of new knowledge, but generally much more is
needed to induce the application of this new knowledge.
In the planning of a technology transfer program, pro-
vision should be made for creating as many opportunities as possible
for establishing face-to-face communication between research workers
and representatives of user agencies. The best way to do this
would obviously be the involvement of potential users in the research
process itself. Very few publications contain practical guidelines
for effectively involving practitioners in research. Odendaal
identified opportunities for practitioner involvement at various
stages of the research process.
If technology transfer is equated to research application,
the highest success rate occurs where a user agency conducts its
own in-house research. In the real-world situation of water pollution
research, in-house research by user agencies represents only a small
portion of the total effort, with the bulk of the work being done
through government funding. In technology transfer, actions origi-
nating with the research and research funding agencies are known
as "push," while those arising with the user agency are known as
"pull." The major effort to effect technolgoy transfer should be
"push."
The first step toward the goal of research application
should be a proper assessment of user needs well in advance of
research planning. Approaches in assessing user needs include
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questionnaires, surveys, workshops and the establishment of special
committees with user representation. User input is necessary in
research planning and technology transfer must be built into a
project during planning stages.
Close contact between user and researcher during the
research and development process promotes technology transfer
through a conditioning effect on both parties. The researcher
gets a better grasp of the practiced problems and the user has
a directive influence towards keeping the research user-oriented.
There are various ways in which user agencies can be involved in
the research process such as: direct participation in the research
process, research funding by user agencies, steering conmittees
and advisory panels and people transfer.
To increase the probability of application, research
findings should be-packaged in a format and language that is
understandable and acceptable to the user. It is envisaged that
most research agencies and research funding agencies will pro-
gressively recognize the importance of the vital role of user
involvement in research for promoting technology transfer, and
that user involvement will become standard practice in research
programs which aim at user application.
Erlich (Namibia) commented that the less developed a
country is, the smaller is the "pull" and the greater is the "push."
In these countries there is ignorance or resistance to research.
Engineers and scientists realize that they need a lot of "push"
to overcome this resistance. Odendaal (South Africa) agreed
without further comment.
E. Paper E: "Packaging of Information - Part and Parcel
of Successful Technology Transfer," by
M. J. Pieterse (South Africa)
Technology transfer in its broadest sense encompasses
the collection, documentation, and dissemination of scientific
and technical information, including data on the performance and
cost of using the technology; the transformation of research and
technology into processes, products and services that can be
applied to public or private needs; and the secondary application
of research or technology developed for a particular mission that
fills the need in another environment.
Information transfer was defined as the act of informing
or providing information about technological changes and advances
through visual, audio and written media. The end result of tech-
nology transfer (or information dissemination) is to create aware-
ness and stimulate interest in new technological developments.
Technology transfer is the sum of those activities leading to the
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adaptation, adoption or demonstration of new technologies where
the audio, visual and written media provide a partial vehicle for
accomplishing the transfer.
For any technology transfer program, the necessary
technology must be available or be made available by means of
research and development. It is estimated that approximately
60% of the developed literature is unpublished material which
is usually very difficult, if not impossible, to obtain. Only
40% of the total developed literature is visible, i.e., available
for use. It is estimated that over 60 million pages of scientific
and technical visible literature are distributed through 80,000
journals and 300,000 monographs annually. In a multi-disciplinary
field like water, there is much information available and much more
to come, all "begging" to be used.
Technology transfer may involve more than one organi-
zation as well as several key persons, e.g., the director of the
research organization, the researcher and the technology transfer
specialist. The technology transfer specialist should, to a
certain extent, be a strategist who designs environments in which
individuals are afforded opportunities to learn. The technology
transfer specialist should be able to adopt new ideas, should be an
opinion leader within the organization, be an excellent communicator
and an expert on tailoring and packaging of information with a view
to its application.
There is a need for research findings to be tailored and
packaged in a format and language that is understandable and
acceptable to the user. There are many packaging techniques which
can be used to transfer new findings or to transfer recent research
into a format which will be of practical use to designers, con-
sultants and decision makers. Among them are mass media tech-
niques (e.g., news release, television, radio), publications (e.g.,
newsletters, pamphlets, brochures and bulletins, trade journals
and organizational scientific publications, capsule reports,
state-of-the-art reports, manuals, handbooks and technical reports)
and other techniques (e.g., films and video tf.pes, displays and
exhibits, seminars, short courses, workshops and conferences,
demonstrations, education and personal contact).
Hall (South Africa) commented from the floor that there
is a gap between the practitioner and the researcher and that
we need to close or eliminate this gap. Alexander (South Africa)
commented that the researcher must read the literature if he wants
to succeed, but the practitioner can often do his job adequately
without referring to the published literature; therefore, the tech-
nology transfer specialist has to compete for the practitioner's
time. According to Alexander (South Africa), the biggest gap in
technology transfer is lack of comprehensive state-of-the-art reports.
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F. Paper F: "Role of Equipment Suppliers," by
J. Bernard (France)
Equipment represents one of the essential elements in
the transfer of technology. The exchange of knowledge between
researchers, designers, manufacturers and users is not equally
easy in all cases, but in a free competition economy, the infor-
mation is diffused very rapidly. Depending on the countries and
the final owners and users of the equipment, the extent of
technical knowledge and of the responsibilities demanded from
equipment suppliers may be highly different, and this influences
the efficiency and rapidity of technology transfer.
There is always a need for new equipment. This need
may arise from: new regulations in terms of treatment levels,
metropolitan development, economical evolution, better work con-
ditions, reduction in personnel cost, improved reliability of the
process, adaptation to large flow rates, and cost reduction.
Development of new equipment, which takes place in several
stages, is more or less extended in time depending on the importance
of the equipment and its novelty. Three major stages may be deter-
mined as follows: (1) small pilot unit; (2) industrial-scale pro-
totype unit; and (3) first standard units. It is essential that
equipment designed to convey or treat wastewaters and/or sludge be
subjected to extensive full-scale tests under the environmental
conditions they will meet, prior to being marketed.
A trustful cooperation between the manufacturer and the
user is the key to a successful development work. The problems
and defects which are met and the corresponding repairs and remedies
must be recorded in all cases. It is essential that the manufacturer
takes the operators opinion into account and conversely.
The equipment role in technology transfer takes three
major aspects: (1) technical exchange between the user and the
equipment manufacturer; (2) technical exchange between equipment
manufacturer and process (or plant) designer; and (3) diffusion
of technological information from one operator to another, from one
designer to another, and sometimes from one manufacturer to
another.
In environmental protection, information sources are
immense. The number and frequency of events are among the highest
in the various fields of industrial activity. Many reviews dif-
fuse a large amount of direct advertising on the available equip-
ment and easily draw the attention of the reader. In various
(maybe too many) exhibitions, the general public may be shown new
equipment and given much documentation. The rapidity with which
the release of new original equipment is known in the world is a
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noteworthy fact. This is a remarkable sign of the importance of
diffusion of technology transfer information.
Harley (South Africa) stressed the importance of feed-
back and stated that researchers and engineers do not get any
feedback from operators about the success of their device. Eberle
commented that this was indeed one of the major problems. The
connection between researchers and users terminates at the end of
a project and therefore researchers cannot learn about difficulties
that may come about in later years.
Crook (Australia) stated that the burden of feedback
should not be placed on the client. One of the duties of the
researcher is to get the facts and follow up his research. He
cannot sit in his ivory tower and expect everybody to feed him
like a baby.
Mercer (South Africa) commented that we do not have
enough experience in nutrient removal at the full-scale level.
He asked the audience, when this information becomes available,
to make this knowledge know.
IV. CRITIQUE OF SESSION
All the speakers made very good presentations. Each
speaker presented a specific part of the theme "Technology
Transfer." The presentations formed an excellent session of
technology transfer and presented a current assessment of the
situation of technology transfer with specific recommendations
for improvement in the future. Issues and needs were effectively
addressed by all the papers. In summary, the major significance
of this session was to point toward the importance of technology
transfer today and the need for improvement in the future.
There is wide international interest in all aspects of
technology transfer. The participants agreed with all the speakers
and their presentations. The lack of comments from the floor appeared
to be mainly because the audience agreed with the speakers and did
not have any further comments.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
All the papers presented in this session dealt with a
subject matter which is of great importance in the United States.
As such, all of the papers presented in this session will be valuable
for Americans involved in technology transfer. All the speakers in
this session complimented various United States agencies and organi-
zations, especially the U. S. Environmental Protection Agency,
American Water Works Association and the National Science Foundation,
for their activities and achievements in the area of technology
transfer. There is, however, a continuing need for improvement.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: C
Time: 9:00 a.m. to 12:35 p.m.
B. Theme of Workshop: "Water Pollution Control in
Developing Areas" (Theme 5)
Convenor: P. H. Jones (Canada)
Panelists:
II. REVIEWER
B. Hawerman (Sweden), K. Poppinghaus
(Federal Republic of Germany),
G. G. Cillie (South Africa),
J. R. Simpson (United Kingdom)
A. Name: Kazuyoshi Kawata
B. Position and Affiliation: Professor of Environmental
Health Engineering and
International Health
School of Hygiene and Public Health
The John Hopkins University
Baltimore, MD
III. DESCRIPTION OF WORKSHOP PAPERS
A. Paper A: "Review and Background," by P. H. Jones (Canada)
Jones (Canada) presented a general introduction to
papers that followed. He made note that the topics being presented
could be applied to developed, industrialized societies, but that
they had peculiar meanings for developing countries. Several emphases
were made. They included the important training aspects, infra-
structure development, and the admonition that decision-makers from
the village chief to the prime minister or president must be educated
on the need for both water supply and sanitation and not just one
utility at the expense of the other.
B. Paper B: "Legal and Administrative Aspects," by L. Brynolf
and B. Hawerman (Sweden)
The authors noted the inadequacies in regulations and
administration to deal with water pollution problems in many of the
developing countries. They presented two case studies of "bad
planning" that led to problems and offered features of legislation
and administration, and procedures for dealing with pollution. It
is not that countries do not have regulations. Too often, however,
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the regulations are unrealistic. They may simply forbid pollution
or require the impossible, e.g., the discharge of water back into
the stream at the same quality as it was withdrawn.
The two examples given were problems arising from (1) the
combined wastewater from an abattoir, cannery, and tannery of the
Botswana Meat Commission in Lobatse and (2) the sewerage system
from Molepolole, a major village in the country. The Lobatse plant
is a secondary plant with provision to treat 60 to 70% of the waste-
water by tertiary treatment for reuse in the abattoir. Although
designed by a reputable consultant, problems have arisen. They
included (a) the repeated discharge of untreated or partly treated
wastewater into the normally dry river bed; (b) no existing established
effluent standards; (c) increase in nitrite and nitrate concentra-
tions in groundwater in the area where the effluent is used for
irrigation; (d) sulfide and sulfur problems in the biofilters due
to the high concentrations of sulfate from the tanning process; and
(e) sludge and solid wastes for which management had not been
arranged initially. The problem at Molepolole involved the siting
of the sewage oxidation ponds only approximately 300 m from wells
of the village water supply without a thorough pre-assessment of
the threat of pollution.
The authors suggested pollution control legislation with
actions based on general consensus, administrative authorities to
provide necessary expertise and enforcement, and procedures for
handling matters as they arise in various situations. By the term
"consensus," the authors were conscious of political implications,
for in every development project, it is a rare occurrence for it to
benefit all parties. It was indicated that water pollution control
legislation should cover quantity and quality of all water resources
and that the need for pre-assessment of each project is an essential
part of legislation. Establishment of a Water Board, which will have
the function of a "water court" to deal with water supply and water
pollution problems and concerns was suggested as a part of water
legislation. A Water Resources Department was also suggested to
act as a policy-making and co-ordinating organization staffed by
experts to advise the Water Board and be responsible for inspections.
Nebiker of the World Bank emphasized that the World Bank,
although it is a lending institution, is also concerned with needs
of countries. The concern of the World Bank is for the poorest
countries, largely in West Africa, where there is an overwhelming
need for water and where the cost for water is exceedingly high.
It was evident that he would like to see more consideration given
to appropriate technology. He stressed the need for water and
wastewater services to move toward financial autonomy, i.e., self-
financing through water fees and sewer service charges, without
which maintenance programs cannot be set up realistically on a sound'
basis.
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Lever (South Africa) called the attention of the session
to the all important difference in the meaning of the words
"practical" and "practicable." The sense of the presentation was
"practicable," i.e., technically and economically feasible. Lever,
taking South Africa as an example, commented that there is little
industry-government cooperation and indicated that industries are not
required to submit impact studies.
Best (South Africa) took issue with Level (South Africa)
pointing out that there is increasing cooperation between industry
and government in South Africa even in the absence of specific legis-
lation. He suggested the need for the establishment of one authority
for an integrated approach to pollution control.
Rivas-Mijares (Venezuela) also pointed to the importance
of appropriate technology and stressed the need for adaptation not
only to environmental conditions but also to socio-economic and
cultural conditions. He supported the concept of technology trans-
fer from the industrialized to the developing countries but with
appropriate adaptation.
C. Paper C: "Training and Education," by K. Poppinghaus
(Federal Republic of Germany)
The author's assignment was a difficult one since
"training and further education in water pollution control in
developing countries" covered an extremely wide scope and since
situations vary from one developing area to another. The problem
was compounded by his reference to "developing and threshold
countries."
The need for hierarchically-structured training and for
expertly-trained personnel was recognized. He noted the need to
develop strategies, on a short-, medium- and long-term basis to
deal with critical shortages of professionally trained personnel.
The means to develop manpower which were suggested ranged from
formal education at a university level to seminars, workshops, and
on-the-job training. The shortcomings of technical education in
developing countries was examined and proposed programs and assess-
ments of training to address the needs in manpower development were
presented. The contributions made by the Federal Republic of Germany
in educational aid in developing countries were received. A plea
for a more functional training of German professionals in developing
country engineering applications was also made.
Van Rooyen (South Africa) suggested that the presentation
pre-supposed that people in developing countries lived in formal
townships and communities when, in fact, they live scattered, often
on hill tops. He indicated that the training outlined was far too
sophisticated and pointed out the need for appropriate training.
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Barnard (South Africa) reported that in South Africa,
there has been a recent development of classification of works
according to size and complexity of operations and that training
programs for operators have been established. He sought coopera-
tion with other countries in the exchange of curricula and course
materials.
Rivas-Mijares (Venezuela) recounted the good experience
in Venezuela for training of operators in pilot plants employed
also for research studies. He urged countries to take advantage
of training opportunities available in centers sponsored by Regional
Offices of WHO, such as CEPIS in Latin America.
Jones (Canada) pointed to language as one of the biggest
difficulties in training, especially training of para-professionals.
Kawata (U.S.A.) pointed to the importance of the understanding of
socio-cultural factors and environmental health aspects by senior
experts mentioned in the paper. Environmental methods for the control
of tropical diseases must start with this knowledge.
Nebiker made reference to the series of studies
on training conducted by national working parties for WHO, which
he felt was a valuable reference for many countries. He also indi-
cated that the training discussions at the 1981 AWWA Convention in
Atlanta, Georgia deserved attention, as does the program developed
in PAHO. Nebiker indicated that many of the current training
programs have shortcomings and a fundamentally different approach to
training is needed. Training must focus on the important aspect of
transfer of technology. He also cautioned that often when training
is done, there is no assurance that the trained will remain with
the utilities. It is not, therefore, a one-time effort. He took
issue with the justification of training developing-country personnel
in Europe.
Williams (South Africa), speaking from experience of a project
in Bophuthatswana,indicated that the personality of the educator/
motivator is exceedingly important. A person may understand the
language, but without the understanding of social customs, he may
do more harm than good.
D. Paper D: "Low-Cost Technology," by G. G. Cillie
(South Africa)
Cillie (South Africa) indicated that if low-cost technology
is applied, costs can be reduced substantially and the goal of the
Drinking Water Supply and Sanitation Decade will be possible. He pro-
vided descriptions of some typical water supply processes that may
be used, including closed wells and slow sand filters. Where these
simple systems are not possible in southern Africa, the National
Institute for Water Research has developed a simplified standard
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design for water treatment, i.e., a rapid sand filtration plant
with a post-disinfection step. For sanitation he discussed pit
latrines, bucket system, and aqua privies as examples of rural
areas where centralized treatment facilities are not normally
warranted. For small communities with populations fewer than
5,000, the use of stabilization ponds was suggested; for larger
populations, the South African experience with the "standardized"
orbal treatment plant with only a mechanical process (i.e., a rotating
disc) installed in the orban channels was suggested. Cillie
concluded by stressing the need for training and the necessity in
designs of systems to minimize the operation and maintenance costs.
Without trained personnel, water and wastewater systems have little
chance of continued functioning and with high cost of operation
and maintenance, communities will not be able to afford the services.
E. Paper E: "Problems and Needs," by J. R. Simpson
(United Kingdom)
Simpson (United Kingdom) discussed primarily the control of
excreta-related diseases and the institutional and social develop-
ments that are required to effect the control Sanitary engineering
and environmental health science have had historical roles in the
prevention of diseases. For them to be able to assist communities,
the lack of finances and education in health poses considerable
problems. The need for competent personnel to design, construct,
operate and maintain treatment works was stressed. These functions
may not necessarily be done by the same personnel, but where
possible, those hired to construct plants should be hired to operate
and maintain them. He was cognizant of the acute shortage of
trained personnel in developing countries and, at the same time, aware
that general population must also be educated to use the facilities
properly. An important point made in the training aspects was the
desirability of the transfer of experience equally with transfer of
technology.
The author presented the concept of planned phased improvement
so that over periods of years communities can move toward greater
coverage and increased services. The history of London, England and
of Wales was recalled, as well as the phases in the development of
water supply and wastewater utilities and their effects on morbidity
and mortality.
Wolf (Federal Republic of Germany) remarked that low-
cost technology is just as important in places such as rural
Bavaria. He indicated that consulting engineers in his country
are also reluctant to employ low-cost technology because there
is insufficient fee to be obtained. Rogers (South Africa)
speaking with experience in Tanzania echoed the problem by
Wolf (Federal Republic of Germany). He impressed the session on the
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difficulty that even the Tanzanian engineer faced in seeking cultural
information associated with a sanitation project and implied even
greater difficulties for European engineers. He thought that youth-
oriented service groups such as Peace Corps and Overseas Volunteers
may have some success in reaching people.
Cillie (South Africa) conmented that although most developing
countries would like water piped to every home, this is not warranted.
He advocated standpipes with spring-loaded taps to minimize wastage.
Herold (South Africa) raised the question, "Should you not
learn from history?" He recommended planning early in metropolitan
areas of developing countries for reticulation.
Simpson (United Kingdom) reminded the session that it was
not too long ago even in the United Kingdom that some sanitary
facilities were less than modern. He thought conceptual plans for
water and wastewater systems should be drawn up by multi-discipiinary
teams and ultimately implemented by engineers.
Bennett (Bophuthatswana) indicated that there was con-
siderable progess being made in South Africa. He said that there
is, however, a great need for middle technology personnel and invited
such people to come to South Africa to help people in places like
Bophuthotswana.
Mabale (Bophuthatswana) has had to deal with cholera in his
area in recent time. He emphasized the importance not only of appro-
priate technology, but also of health education programs. The involve-
ment of the people through organized village health committees in
his region is showing good results.
Redshaw (South Africa) felt that there has been much too much
attention paid to community systems when the people in Africa live
largely in rural areas. Provisions of treatment works are often not
practicable and reticulation often out of question. He thought more
attention should be given to on-site systems.
Simpons (United Kingdom) agreed with the comment that water-
carriage systems for waste disposal may not be the solution. He added
that sewer systems are designed for a certain fixed life and that
requirements for replacement costs are real. In the United Kingdom,
much of the existing systems are deteriorating badly today and this
is posing a great problem. Schemes in developing countries will be
no different in years later.
Shelef (Israel) explained that 40% of the world population
is deficient in protein intake. He advocated schemes for resource
recovery and the production of income from products of community
wastes, e.g., fish, algae, water for irrigation, and biogas for energy.
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Williams (South Africa) favored the encouragement of
commercial groups getting into the production of non-sophisticated
equipment for water and wastewater treatment and reminded the
session that diseases such as schistosomiasis can be transmitted
by water contact and not simply by drinking.
Simpson (United Kingdom) commented that "appropriate
technology" is as important in the United Kingdom as in developing
countries. He felt that not enough effort is placed on educating
people to use water supplies properly. In response to the comment on
schistosomiasis he noted that in some irrigation schemes, improper
design velocities have enhanced snail production and thereby the
transmission of the disease.
Geevers (Bophuthatswana), a medical officer, spoke of
the concern for water supply and sanitation, and undernutrition
and their relation to health. He thought there should be rural
planners, as much as there are town planners, who could place,
say, the reticulation system for a community in context of economic
viability as well as public health.
Lind (Sweden), the formal discusser, summarized the
presentations. He noted that there is no sharp boundary between
developing and developed countries. In fact, all societies
continue to develop and societal development was compared to the
growth curve of microorganisms. Looking to Sweden he showed that
domestic water consumption has now leveled off to about 200 to
270 £/capita-d. Industry is recycling its water more today, so
that the net effect is a slight decline in water demand. The
increase in water recycling has been brought about by the strict
legislation increasing the price of water. This development has
taken place over 80 years. He doubted very much that the developing
countries could in a short period of time be able to satisfy most
of the water demand in water-short areas to the level of Sweden.
Economic means to finance facilities to meet the demand will be
difficult to find.
Institution building was important and legal aspects,
training at all levels, and planning were mentioned. A centralized
authority staffed by engineers, biologists, microbiologists, and
legal personnel was suggested and use of practical knowledge in
mechanical and electrical fields, in training programs and training
in-country was stressed. He indicated that sending people overseas
for education had too many drawbacks, that designs of processes
would be simple and that construction will use local materials as
much as possible. Standardized plant designs discussed by Cillie
(South Africa) made a great deal of sense, since standardization
lends itself to easier training in operation and maintenance and
makes for ease of supplying spare parts.
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IV. CRITIQUE OF SESSION
The conference was advertised to include presentations,
research papers and state-of-the-art deliberations on water pollu-
tion control in developing countries, especially since this is
the International Drinking Water Supply and Sanitation Decade.
Whether it was the question of venue or funding or whatever,
many of the third-world countries were not represented. The
state-of-the-art papers lacked fresh, original ideas to make the
session one of vital interest. Furthermore, there were few papers
in other sessions that dealt with problems of the less developed
regions of the world. Although it was evident from a quick,
visual survey that most United States and Japanese conferees were
attending other sessions, nevertheless, the attendance in the
state-of-the-art session was exceedingly good. There was an
interest that seemed to express concern beyond the limited scope
of the theme papers presented. Several of the participants from the
floor were medical officers in South Africa.
There were some semantic problems among those present.
The term "developing countries" was being interpreted loosely to
represent whatever each speaker wanted it to mean and this was not
helped by the use of the term "threshold countries." There was
little said of the wide gap between rural and urban developments
within ? developing country. Therefore, what was advanced as
appropriate technology was often challenged. Most engineers appeared
to look at problems as consultants. They were concerned with pro-
cesses, operation, maintenance, and economics. They were naturally
involved more often with facilities for urban or semi-urban communi-
ties. Those in health departments saw environmental health problems
in rural areas where diseases of the tropic were of concern. There
the populations are often scattered with some living on hill tops.
In such situations sophisticated schemes are too often totally inappro-
priate.
Training received considerable attention of all speakers
but here again, there was a semantic problem. Poppinghaus (Federal
Republic of Germany)mentioned "training and further education in
natural sciences and engineering." He appeared to recognize the
difference between training and education. Fortunately, many who
attended the session interpreted training in the context of fitting
the person to the job. There were expressions in favor of training
to be more practical and to be arranged in-country at all levels
of technical needs. Training of personnel in industrialized coun-
tries was seen by several discussers to be less desirable.
While the understanding of socio-cultural aspects and
health education were mentioned, there was little substance in the
discussions. This is probably understandable, since unfortunately
environmental engineers and scientists rarely are in positions to
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contribute in these areas. The presentations also did not deal
in any depth with health concerns in water supply and sanitation.
The textbook presentation of excreta-related diseases was of
encyclopedic value.
The engineer designing treatment units from the very simple
to the more sophisticated systems to provide barriers to the trans-
mission of diseases of the tropics must understand the diseases,
vectors of the etiologic agents, and modes of transmission. He must
also have an understanding of epidemiology to see through ecological
fallacies. There was evidence that most engineers are ill-equipped
to deal with environmental problems where such knowledge is
necessary.
How much investment in water and wastewater schemes is
required to improve health? This question was not brought up.
Some may have gone away thinking that any amount will have an incre-
mental improvement.
Resource recovery concepts were ably presented in discussions,
but with time limitations not in any depth. An emphasis on this
concept together with the aim of reducing, for example, diarrheal
diseases would have been valuable to the participants.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The theme of the session focused on concerns in developing
areas of the world. The emphasis in the presentations was largely
in the direction of practice rather than in research. However, since
United States government agencies and consulting firms are vitally
involved today in projects in developing countries largely in aid
programs, this area has interest. There are limited numbers of
engineers knowledgeable in appropriate technology to design pro-
cesses and schemes to protect populations from diseases of the tropics.
There is also a wide gap in low-cost technology adapted to problems
in water-short developing areas of the world. The common ground
of tropical medicine and environmental engineering must be seen as
an area where there are scientific inquiries that are needed to be
made. Whether for altruistic reasons or for reasons of maintaining
pre-eminence in tropical health, the scientific community in the
United States should re-establish research programs in tropical
environmental health. These involve the inactivation of etiologic
agents in liquid and in solids fraction, processes for the removal
of organisms, resource recovery built into treatment, and innovative
economic management.
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I. SESSION
A. Day: Friday, April 2, 1982
Hall: C
Time: 2:00 to 5:30 p.m.
B. Theme of Workshop: "Water Recycling" (Theme 6)
Convenor: K. D. Linstedt (U.S.A.)
Panelists: R. D. Heaton (U.S.A.),
D. R. Albrecht (Federal Republic of
Germany), C. F. Schutte (South
Africa), H. I. Shuval (Israel),
G. Eden (United Kingdom)
II. REVIEWER
A. Name: Richard D. Heaton
B. Position and Affiliation: President
Water Reuse Information Services
10 Riviera Court
Littleton, CO 80123
III. DESCRIPTION OF WORKSHOP PAPERS
A. Paper A: "Review and Background," by K. D. Linstedt
(U.S.A.)
Linstedt (U.S.A.) introduced the water recycling theme with
appropriate definitions of reuse terminology for common understanding
These included: (1) Indirect reuse—reuse that occurs when waters
used one or more times are discharged and withdrawn for subsequent
use; (2) Direct use—planned and deliberate reuse of treated
wastewaters for beneficial purposes. Potential reuse applications
were described from groundwater recharge, agriculture, industry,
recreation and aquaculture to domestic or potable reuse. Specific
examples of wastewater reclamation and reuse were summarized at
Phoenix, Arizona; Bethlehem Steel; Japan; Mexico and Israel.
Water reuse is truly a worldwide practice but individual
communities must make the decision to conserve water by recycling
based on the following considerations: (1) water quality; (2) health
effects; (3) institutional restrictions; (4) costs; and (5) public
opinion. With respect to public opinion, it was concluded that
more public education is needed to insure successful reuse efforts.
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B. Paper B: "Water Recycling Systems," by R. D. Heaton
(U.S.A.)
The original intent of this invited paper was to present
a general treatise on the initial treatment required for various
reuses schemes via rivers, impoundments, lakes, groundwater or
directly. Unit processes were to be detailed emphasizing per-
formance and cost. Such a paper, to represent state-of-the-art
conditions, would fill several volumes. Thus, the author limited
his presentation to the reclamation and reuse of municipal waste-
water and detailed cost functions for one United States installation.
Treatment was indicated to be a function of four variables
that affected the decision of a community to recycle water. These
were: (1) the intended use; (2) institutional considerations;
(3) economics; and (4) health considerations and quality criteria.
Beneficial uses of reclaimed wastewater were reviewed and a ten-
step screening methodology was described to identify the potential
market.
Institutional considerations was a general category to
include a wide variety of factors influencing the reuse decision.
The legitimate questions, and approximately 50 were posed, encom-
passed health, political, economic, cost and public issues. In
general, a set of guidelines was developed for use in evaluating
reuse potential.
With respect to health considerations and quality criteria,
a beneficial use was listed along with the basis for establishing
criteria. The prime water quality objective in any reuse situation
is to prevent the spread of waterborne disease. The risk of human
exposure is possible if inadequate safeguards are evident.
Of high importance in the written paper was the description
of water recycling systems with respect to their costs and effective-
ness in contaminant removal. Twenty-four treatment trains were pro-
posed to meet intended reuse situations, ranging from irrigation to
potable consumption.
To provide current cost data, detailed performance at the
Water Factory 21, an advanced wastewater treatment plant operated
by the Orange County Water District Southeast of Los Angeles,
California was presented. The plant has operated successfully for
five years, and maintains some of the best water quality and cost
data available in the United States. In the formal proceedings,
Heaton provided cost information on the facility for the October 1,
1979 to September 30, 1980 period. The purpose of the presentation
in Cape Town was to update all data through September 30, 1981. This
allowed close examination of inflation factors and provide the most
current costs available.
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Of significant importance it was noted that a 45% increase
in costs had occurred over the one-year period of 1980-1981. With
that jump in prices, it was indicated that AWT and several reuse
situations seem doomed to economic failure. The plant was designed
to treat 57,000 m^/d through all of the unit processes and 19,000 m3/d
through the R0 system. In 1951, only 19,000 m3/d were treated with
AWT and 15,000 m^/d with R0. This was due, not to plant deficiencies,
failures, or design problems, but to heavy winter rains that pro-
vided natural recharge, reducing the injection barrier demand that
the plant normally provided. When the facility did not operate
at design capacity, unit cost suffered as indicated in the period of
1980-1981.
To give a more accurate picture of current AWT costs,
all cost data were adjusted to reflect full flow at a 90% plant
factor. The results indicate a blended-water cost of 22
-------
Other discussers challenged the need for water reuse at all, which
was quickly dispelled with factual data on worldwide supply and
demand relationships.
While chlorine was used as the principal disinfectant
in most cost data, its use is not mandatory in the United States
and other alternatives will suffice. The question was raised of
why adjusted cost figures for Water Factory 21 were lower
in 1981 than in 1980 with the response than design flows were low
in 1980 as well. Had those data been adjusted in a similar manner,
it would have given a more realistic impression of inflation over
a one-year period.
Chalmers (United Kingdom) suggested that an early EPA
statement was still true, i.e., renovated wastewater costs are
prohibitive unless there is no other choice. This was refuted by
Heaton (U.S.A.), using Denver as an example where other supply al-
ternatives are available but more expensive than potable reuse.
C. Paper C: "Water Recycling—Industrial Applications,"
by D. R. Albrecht and K. Imhoff (Federal
Republic of Germany)
The application of industrial water recyling techniques
was presented by Albrecht (Federal Republic of Germany) with examples
in various manufacturing plants such as: steel; pickling and plating,
coal mining and coking; sulfite cellulose and paper production; sugar
works; and power plants. Special emphasis was given to metal-
finishing works and paper mills in Germany.
In 1975, the total industrial fresh water consumption
was 29.9 x 10" m^/d, in addition, 57.4 x 10^ m^/d of recycled
water was used. A decrease in fresh water consumption was noted
over the years while overall demands have increased. This lent
credence to the importance of internal water recylcing in various
wet industries.
Industry, depending on the product and proven procedures,
can utilize either open- or closed-loop recycling schemes. Open-looped
implied a cascading system where the same water was used successively
in one or more operations prior to treatment. Closed-loop implied
treatment immediately after use and recycled for that same use with
make up as needed.
Some specific examples in the Federal Republic of Germany
were:
(1) Steel Mills. The Salzgitter works in Northern Germany
has a water demand for 25-30 m^/s, but a fresh water surface supply
of only 2 m3/s. Optimizing internal recycling has met the demands
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for cooling, waste transporting and process waters. In another
steel mill, fresh water demands were reduced by reuse from 84 nr/ton
of steel produced to 4 m^/ton.
(2) Pickling and Plating Works. Waste from these facilities
are normally hazardous in nature and concentrated in geographical
areas. In the Ruhr area alone, there are 607 metal-finishing plants.
Water recylcing has become mandatory from both a resource and
economic viewpoint. Multi-stage, counter-current and spray-rinsing
techniques have reduced water consumption by as much as 99%. Ion
exchange technology has become increasingly important for treatment
and recycling.
(3) Coal Mining and Coking. The mining of a ton of coal
requires 2.5-5 m^ of water and coking an additional 5 m^ with primary
uses for washing and cooling. Eighty percent of the wastewaters
are lost to evaporation but the remaining 20% must be reused to con-
serve valuable supplies.
(4) Sulfite Cellulose Plants. With a water demand of
500-900 m3/ton of cellulose and strong wastewater production, these
facilities become known as the greatest water polluters. Water
demands have been reduced drastically through recycling techniques
but one firm had to spend 22% of the total investment costs of
wastewater treatment and air pollution control.
(5) Paper Mills. Sulfite cellulose is used for paper
production and one German mill was able to reduce raw water con-
sumption from 12 m^/ton of millboard to 1.3 m^/ton by applying
recycling techniques and water conservation measures.
(6) Sugar Works. In sugar plants, water reuse has allowed
consumption to reduce from 10-14 m^/ton sugar beets to 1 m^/ton.
Wastewater is often stored during the process season and treated
at a later date.
(7) Power Plants. Electrical consumption has doubled
every 10 years since World War II. Once-through cooling is no
longer possible and 1-2.5 m3/s of fresh water are consumed for
every 1000 MW produced. Multiple-cooling installations are 25%
more expensive than single use.
The invited discusser, Baumann(U.S.A.) agreed that industrial
water conservation has reduced consumption by as much as 70%. Con-
servation preceded reuse which could close the cycle and achieve
zero discharge. The costs to reduce flows by 90% are 10% of those
required to satisfy the remaining 10%. The last fractional increment
is the most expensive. Most agreed with the sophistication of
counter-current rinsing techniques but questioned the overall salt
balance in some industries that generate 2 tons of salt for every ton
of salt removed.
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D. Paper D: "Water Recycling for Domestic and Agricultural
Applications: State-of-the-Art," by
C. F. Schutte (South Africa)
Agricultural reuse concepts are well documented and Schutte
chose to emphasize the more controversial potable reuse situations.
Indirect reuse, indirect recycling and direct recycling of treated
wastewaters in domestic supplies were discussed with regard to
engineering, public health and quality aspects.
There is very little difference between indirect and
unplanned use of water containing effluents and planned recyling
of reclaimed wastewater for potable purposes. The most important
consideration in all reuse situations is that a polluted source is
used for the production of drinking water.
Direct recycling has been taking place on an intermittent
basis since 1969 at Windhoek, South West Africa. The 3800-m3/d plant
provides 20% of the water demand on a yearly average basis. But
South Africa, with critical water supply problems, is looking at
implementing potable reuse at other cities including Cape Town.
Thus, the water supply regulator and research agencies keep a close
watch on the issues of importance outlined below:
(1) Public Health Aspects. Safety of reclaimed water for
human consumption is provided by existing standards for microbiological
and some organic constituents. However, the question of what is safe
for micro-organics is not so readily answered. "Safe" therefore
must be qualified by a degree of risk for the particular situation.
A relative approach of comparing reclaimed effluent quality with
conventional supplies is not entirely satisfactory because it does
not guarantee that either are safe. Schutte called for the establish-
ment of an absolute reference quality and the development of drinking
water criteria/standards regardless of source. Additional require-
ments such as treatment, monitoring frequency, and multiple barriers
may be necessary to insure reuse safely.
(2) Epidemiological Evidence. It is difficult to identify
subtle changes in a community's health pattern as well as to identify
causal relationships or the effect of socio-economic forces. The
two studies completed to date in Los Angeles and Windhoek indicate
no meaningful relationship between consumption of reclaimed water
and disease prevalence.
(3) Technology. It is an engineering assumption that any
quality of water can be produced from wastewater if one is willing
to pay the price. At extremely high costs, reclamation becomes
infeasible. Realistic requirements must be set for unit processes
and treatment trains without compromising quality.
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(4) Public Attitudes. It would appear that public
attitudes toward reclaimed water are not a significant obstacle
in project development but adequate public information programs
are necessary to insure success.
Current recycling projects comprising advanced reclama-
tion technology are performing exceptionally well if judged by
the quality of water that is being produced. Schutte expressed
the hope that results from research on quality parameters,
toxicology and epidemiology will become available in the near future
to allay the apprehension still evident in parts of the scientific
community towards potable reuse.
E. Paper E: "Health Risks Associated with Water Recycling,"
H. I. Shuval (Israel)
Shuval (Israel) began with the premise, "Before you take
the risk, is there anything socially rewarding or beneficial from
wastewater reclamation?" His reply was decided yes and he pro-
ceeded to defend that position.
While wastewater is 99.9% pure water, the remaining 0.1%
of chemical and biological contaminants can result in serious health
problems unless appropriate measures are taken. Indirect reuse
again questioned where in times of severe drought, surface waters
may contain 100% of recycled wastewater.
Conventional water treatment plants were said to be entirely
inadequate to handle what may be a toxic waste. Criticisms were
leveled against the water supply industry in the United States because
of its hesitance to recognize covert reuse which is perhaps the most
common and, in many ways, the most dangerous.
The question was posed - why should direct reuse be subjected
to different standards and stricter requirements? Planned potable
reuse programs must be submitted to municipal, local or national
health authorities for review and/or approval. Under these circum-
stances, the initiators must accept full responsibility for any
risks. In signing approval, health officials accept full responsi-
bility both legally and morally that the project will not have
negative effects. Thus, it is generally accepted that reuse situations
will require more and extensive health regulations and standards.
Shuval (Israel) urged a pragmatic approach to potable reuse.
That is, in water short areas sub-potable reuse schemes should take
precedent, postponing for as long as possible the other decision
until more information is available on epidemiological aspects. Shuval
(Israel) quoted statements from the 18601s that human wastewater should
be applied to the land for fertilizer value to nourish the world and
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prevent pollution of rivers or transmission of disease. There are
social benefits to reuse from land application to potable use. In
Israel, and to further satisfy the question of demand versus
supply, the country is already using more water than they have, i.e.,
at the expense of mining precious groundwaters. In the future,
the gap will have to be closed by reuse.
The author clarified his earlier statement of "I'd rather
drink clean water than cleaned water." This referred to his
hierarchial water use where, and if possible, the highest quality
water should be used for drinking. Water reclamation plants and
water plants in general should be considered places where the
highest quality personnel and standards apply. The main message
was an indictment of the water industry, as a whole, which has
neglected the amount of wastewater in surface supplies and its
hesitance to upgrade treatment from simple filtration and chlorination.
He had complete faith in cleaned water when one knows what he is
dealing with and plans accordingly. He was convinced that Windhoek
water., with its rational design, was safer than drinking New Orleans
water without recognized safeguards.
In response to a question on the value of epidemiological
studies, -in lieu of unknown chemicals being added daily to water
supplies with 20-year latency periods before clinically diagnosed
diseases are evident; Shuval (Israel) agreed that the research
may be misleading because of synergistic effects.
A number of comments related to the fact that so much more
needs to be known before we can endorse potable reuse. The author
rebutted with the fact that public health was advanced before we
had all the information especially with respect to viruses. He
concluded with suggestions that water is the only food product that
is manufactured, sold, and delivered before final testing. It should
be much more expensive than it is to insure its safety.
Shelef (Israel) commented that some decisions are needed
now; we cannot take all the time to assess risk. In his opinion,
the 1963 U.S. Public Health Service drinking water standards were
derived without empirical health data and constitute a greater
risk than allowing potable reuse today. With respect to instrumenta-
tion3 in his generation students could isolate 20 pure substances
in the ppm range. In the 1970's better resolution resulted in
ppb detection and in the 80's detection at the ppt level is achieved.
Extrapolating this to the year 2000 would result in the ability to
determine individual molecules of the 5 million known substances.
In one glass of water, researchers could easily find one molecule
of cobra venom or mustard gas. These results could be sensationalized
unless a line is drawn somewhere. Proper use of public funds and
realistic risk must enter the decision.
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F. Paper F: "Water Recycling - Research Needs," by
A. L. Downing and G. Eden (United Kingdom)
Eden (United Kingdom) proposed that reuse of potable
supplies is the most critical area for research with health effects
being paramount. Since the duty of a water supply agency is to
provide the public at all times with a wholesome water, a major
objective of research is to reassure the public of its safety. A
further objective is to carry out this mandated function economically
and reliably. This might include consideration of reuse as a means
of supplementing inadequate conventional sources.
Specific areas of research needs include: (1) Epidemio-
logical Studies—while these efforts represent the ultimate test of
reclaimed water, they must be coupled with tests capable of more
rigorous control; (2) Animal Studies—these tests are limited be-
cause of extrapolation problems to humans, lifespans and inadequate
sensitivities at nonlethal levels; (3) Bacterial/Cell Cultures—
mutagenic screening tests are useful as primary indicators, but
correlation of lab results with practice is difficult;
(4) Biodegradability Tests—it is important to select one test from
many that accurately predict the behavior of new compounds in the
environment and not just in laboratories; (5) Chemical Analysis—
non-volatile organics remain difficult to analyze with GC/MS tech-
niques and the problem remains after identificationand assessing
harmful biological effects; (6) Microbiological Monitoring—Rapid
methods of ascertaining microbiological safety are needed,
especially with viruses; (7) Standards—standards must be based
on the best available information, yet be realistic; (8) Treatment
Processes—in specific areas, very sophisticated methodologies
will be needed to meet stringent quality criteria; (9) Industrial
Effluents—control of pollutants at their source is becoming
increasingly important and mandatory in reuse situations; and
(10) Administrative Control—realistic approaches to hazardous wastes
are needed without over-reactions or shear neglect.
Eden (United Kingdom) closed his formal comments with
inferences to needed changes in water/wastewater systems. Using
water to dispose of human wastes was like using a 2000-ton train
to remove 1 ton of rubbish and then throwing away the train at
the end of the journey. With new thinking and additional research,
on-site reclamation schemes may well prove to be practical approaches.
IV. CRITIQUE OF SESSION
Except for papers by Heaton (U.S.A.) and Shuval (Israel),
the session was not representative of state-of-the-art conditions.
The first author took time to offer current cost data and upgrade
year-old proceedings. As expected, potable reuse generated the most
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enthusiasm and controversy. The current state-of-the-art is
frankly that a lot remains unknown, but to sit idly and wait for
all the answers is not practical. Risk must play a proper role
in resource alternatives as well as economics.
The same questions appear to have arisen for the last
five years. Why should potable reuse be treated any differently
than indirect reuse situations currently being touted as safe?
And the same answers come forth with a predominance of South
African attitudes. Don't judge a water by its history but its
present quality. Is it safe?
Industrial and sub-potable reuse is well founded with
practical experiences worldwide. South Africa, with the only working
potable reuse endeavor in nearby Southwest Africa, is interested
in expanding the concept to other water-short areas. Criticisms
outnumbered constructive comments and the country has had to establish
its own proof. Sensitivities to world opinions are evident and
South Africa's leadership in the field is a lonely position.
Because of a lack of promulgated reuse standards anywhere
in the world, South Africa's multiple barrier effect is reasonable.
Contrary to opinions expressed at Toronto in 1980 that potable reuse
would never be allowed in the United States, it is a viable but
very site-specific option that should not be ignored.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Interest remains high in wastewater reclamation and
reuse, perhaps in a greater fashion overseas than in the United
States. Water reuse activity in this country is very much a
function of the weather and just as fickle. With the 1977-78
droughts in California came literally hundreds of legislative
actions and fu _Ing proposals. But we forget quickly and when the
rains came, interest subsided and apathy returned. Perhaps we
respond better to crisis than proper planning beforehand.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Water Quality Problems
Caused by Toxic, Nuisance
and Nutrient Chemicals
II. REVIEWER
A. Name: Clifford W. Randall
B. Position and Affiliation: Lunsford Professor of Civil
Engineering
Virginia Polytechnic Institute
and State University
Blacksburg, VA 24061
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation SI: "Removal of Pesticides and
Herbicides by Means of Adsorption
on Activated Carbon," by
D. V. Heroes (Belgium)
Granular activated carbon (GAC) was used to treat a waste-
water containing chlorophenolics and phenoxycompounds, e.g., methyl -
chlorophenoxy acetic acid, phenoxyacetic acid and phenoxypropionic
acids. The study was conducted over a period of three years and one
month using two GAC columns in series operated at an average flow
rate of 14 m^/h, with a contact time of 43 min in each column. A
total of 123,000 m3 was treated during the course of the investigation.
GAC columns were shown to be effective way to remove chlorophenolics
and phenoxycompounds from wastewater. Influent chlorophenol con-
centrations ranged from 0.8 to 6.4 mg/£ while effluent concentrations
ranged from 2.6 to 16 ygJis for overall removal efficiencies ranging
from 99.29 to 99.94%. Influent phenoxycompound concentrations ranged
from 13 to 129 mg/ji with effluent concentrations of 57 to 484 pg/it
for removals efficiencies ranging from 99.60 to 99.93%. Organic
carbon loadings on the activated carbon of approximately 20% could
be obtained with average flow conditions.
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B. Poster Presentation S3: "Adsorption and Biodegradation
of Linear Alkylbenzene Sulfonates
(LAS) by Activated Sludge," by
K. Yoshimura and A. Nakae (Japan)
The authors indicated that adsorption of LAS homologues/
isomers on activated sludge depended on the structure of the hydro-
phobic group of LAS. This tendency was consistent with that of their
biodegradabilities. No accumulation of LAS and its biodegradation
intermediates in activated sludge was observed. The degree of
adsorption of commercial-grade LAS by activated sludge was a function
of both the alkyl chain length and the location of the phenyl group
on the chain. The longer the alkyl chain length and the shorter
the distance of the phenyl group from the far end of the alkyl chain,
the greater the adsorption of the LAS. The principal conclusion
of these results was that adsorption of LAS by activated sludge
depends on the hydrophobic properties of the molecule. The results
further showed the the LAS was rapidly biodegraded and that the
likelihood of biodegradation was also directly related to the hydro-
phobic properties of the LAS molecule. In summary, LAS molecules
that are readily adsorbable are also readily biodegradable, and
vice versa.
C. Poster Presentation SI4: "Polyelectrolyte Toxicity
Tests by Fish Avoidance Studies,"
by L. D. Spraggs, R. Gehr,
and J. Hadjinicolaou (Canada)
A unique type of dynamic fish toxicity testing apparatus
was developed. A continuous flow channel is divided by a partition
for about one-half of its length. The chemical to be tested is in-
jected on one side of the partition just downstream of its upstream
end. Overhead video cameras and UV light are used to record the
preferences of fish for the side with the injected chemical compared
to the side without chemical. The cameras record the position of
the fish every five minutes rather than operating continuously. The
authors used 100 six-month-old SaJbmo gcuAdne/U (rainbow trout)
for each test at a temperature of 13-15°C. The chemical concentration
that caused 50% avoidance was determined.
The apparatus was compared to three other types of toxicity
tests: the static 96-h LC50 test for fish, the Microtox EC5Q test,
and 50% inhibition of algae [SelanaAtAm capA^coAnntuni). Rainbow
trout were used for the static fish test. Two polyelectrolytes
commonly used for water/wastewater treatment, and their monomers,
were selected for testing. The monomers were polyacrylamide and
dimethyldiallyl ammonium chloride, referred to as monomer A and B,
respectively.
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The conclusions were : (1) Polyelectrolytes are signifi-
cantly more toxic than their constituent polymers; (2) Results for
phosphorescent bacterial toxicity tests are inconsistent with those
from fish and algae tests: (3) The dynamic fish test conducted over
a relatively short period is at least as sensitive as the acute
static fish test. It could actually yield information such as
preference for substances actually known to be toxic from results
of the static test; (4) From the magnitude of the concentration of
polyelectrolytes showing significant toxicity, it appeared that
discharges from waste treatment processes utilizing these poly-
electrolytes could be hazardous to receiving water bodies.
C. Poster Presentation SI5: "Mineralisation Problems in
the PWV Complex--The Identifi-
cation of Viable Solutions by
Means of a Suite of Deterministic
Models," by C. E. Herold (South
Africa)
The Pretoria-Witwatersrand-Vereeniging (PWV) complex depends
for its water supply on the River Vaal, which is also the sink for
much of the pollution emanating from the region. With the onset of
the rainy season, accumulated salts are washed off the catchment,
causing unacceptably high TDS peaks in the primary water source. The
salinity build-up is compounded by the feedback effect as effluents
are recycled into supply. A suite of numerical models having
meteorological data as basic input has been developed to simulate
daily or monthly TDS concentrations at key points in the system
for any specified conditions of demand or catchment development.
Parameters relating TDS levels to economic costs are used to deter-
mine the benefits to be derived from adopting one or another of
many different water resource management and pollution control strate-
gies.
Among the findings to emerge were the following: (1) Within
the PWV region the flow-weighted average increase in TDS concentrations
during one usage cycle was 500 mg/£; (2) More than half of the TDS load
originating in the southern PWV region were derived from diffuse
sources attributable to human activities; (3) The storage of salts
in the soil moisture zone and their transport via interflow play a
significant role in the routing of diffuse source mineral pollutants
through a catchment; (4) A strong correlation (r = 0.926) was found
between industrial water demand and the rate at which diffuse source
salts were generated.
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D. Poster Presentation S18: "Microbiology of Nutrient
Removing Activated Sludge,"
by M. A. Hart and L. N. Maimed
(South Africa)
The modified Bardenpho nutrient removal system was
described. The build-up of microbiological life from plant start-up
was recorded and AclneXobacXeA species was identified as a major
component of the Gram-negative group of bacteria in a number of
plants.
The daily development of microbial life in a Phoredox
(modified Bardenpho) activated sludge system was monitored during
start-up. Settled sewage was used as the only seed. The most
important observations were as follows: (1) CluAonomld worms
appeared in large numbers during a temporary breakdown of the sludge
removal equipment; (2) At the end of two months, AclniUobacXeA were
present in scanty numbers and the experimental addition of primary
clarifier sludge to the system greatly increased the kclnztobajcXvi
population and established their dominance; (3) Examination showed
that the ktinoXobacXeA cells contained phosphate deposits which
diminished under anaerobic conditions and increased under aerobic
conditions. Poly-S-hydroxybutyrate (PHB) granules in the same
cells did the opposite; (4) Filamentous organisms such as NocaAcUa
appeared to be able to accumulate polyphosphate.
The authors also surveyed the relative abundance of
several species of bacteria in four nutrient-removing activated
sludge plants and found that kc^neXobactzA/HoAa.xeMa species
clearly dominated in each of them. Nutrient removal plants typically
suffered from poorly settling sludges, particularly during winter.
E. Poster Presentation S25: "Interstitial Meiofauna as
Indicators of Sandy Beach
Pollution," by T. P. McClurg
and J. D. Whitehorn (South
Africa)
The authors proposed the assessment of the community
structure of life forms adapted to the interstices between sand
grains as indicators of the degree of pollution to which a sandy
beach has been subjected and are performing the developmental
research to make the approach feasible. To accomplish this, they
are surveying the meiofauna of two beaches remote from major sources
of pollution and that of some beaches at relatively polluted sites,
all on the Natal, South African coast.
Results showed that the sand of beaches is, indeed, heavily
populated. They found 36 organisms from 16 species in a typical
50 m£ sample of sand. Nematodes were usually the major constituent
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and were generally found to be resistant to pollutants, whereas
copepods were second in abundance and some were relatively sensi-
tive to pollution. The nematode/copepod ratio was recommended as
an indicator of beach pollution.
IV. CRITIQUE OF SESSION
In Poster Presentation SI, the author showed that
efficiency varied with flow rate through the columns, yet very
low effluent concentrations were obtained for all conditions
used. Perhaps the most significant aspect was the demonstra-
tion that pesticide-herbicide concentrations of approximately
100 mg11 can be reduced to effluent concentrations of approxi-
mately 0.060 mg/£. using GAC columns.
The procedures used by the authors of Poster Presentation
S3 were very rigorous, sophisticated and thorough and can be accepted
with confidence. It is doubtful that the results will be found
transferable to other types of synthetic organics such as DDT
and ABSj and the universal usefulness of the principles demonstrated
herein for the screening of environmentally persistent organics is
not likely. However, the results may provide an interesting insight
into the mechanisms of the contact stabilization process of activated
sludge. Perhaps the rapid adsorption of organics by activated sludge
is more strongly related to their hydrophobic properties rather
than to their colloidal nature. Results published in recent years
have shown that a highly colloidal waste is not a sufficient condition
for the contact stabilization phenomenon to occur.
The most interesting aspects of the results of Poster
Presentation SI4 were the very high toxicity of polyelectrolytes
compared to the toxicity of the monomers used to build them, and
the comparison of the dynamic test to the static fish test. It
took 140 mg/£ and 900 mgft of monomers A and B, respectively, to
kill 50% of the fish in the 96-h static test, but only 0.4 mg/£
and 0.2 mg/£, respectively, of the polyelectrolytes made with those
monomers. The difference was enormous and implied that polyelectrolyte
use for wastewater treatment is potentially damaging to a receiving
body of water. This aspect clearly deserves field investigation.
The high toxicity of the polyelectrolytes was also indicated by the
dynamic fish avoidance test and the 50% algae inhibition test. The
concentrations for 50% fish avoidance, however, were twice the con-
centrations of the LC50, indicating that fish may unknowningly remain
in the presence of fatal concentrations of polluting chemical. By
contrast, the fish avoided concentrations of monomer that were only
a very small fraction of the LC50 concentrations.
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The failure of the Microtox test to indicate toxicity
for chemical concentrations that were even remotely close to toxic
levels indicated by the other three tests casts serious doubt on
the usefulness of this approach. For polyelectrolyte C, it erred
by a factor of 37.500X, compared to the LC50 concentration. The
smallest error factor was 96X compared to LC50 concentrations.
In conclusion, though, it did not appear that the authors
demonstrated that the dynamic test was superior to the acute static
test. For the low toxicity monomers, the avoidance levels were much
less than the LC50 concentrations whereas for the highly toxic
polyelectrolytes the avoidance levels were greater than the LC50
concentrations. Considering the high equipment cost of the dynamic
test equipment, it is doubtful its use could be justified. In-
terestingly, the 50% algae inhibition test most closely approximated
the LC50 results.
In Poster Presentation S15, Herold (South Africa) adapted a
group of specific models into a relatively comprehensive approach
that can be used to simulate the complicated interdependence of water
resources, water demands and water pollution in a complex, industrial
watershed. The problem evaluated was the buildup of total dissolved
solids (TDS), but it seems highly probable the models could be used
to project the buildup of a variety of diffuse source pollutants
in a watershed where partial recycle is occurring. The approach
appeared to be particularly valuable for the evaluation of proposed
basin-wide management and planning options and parameters relating
TOS levels to economic costs are included to facilitate such evaluations.
The developmental work that has been performed by the author is im-
pressive.
In addition to the IAWPR poster presentation, the author
will present a related paper at an IAHS conference at Exeter,
England in July, 1982. Preprints of that paper can be obtained from
the author as can copies of the computer program documentation. His
address is: Dr. C. E. Herold; c/o Stewart, Sviridov & Oliver;
P. 0. Box 61672; Marshalltown; Johannesburg, 2107 South Africa.
Poster Presentation S18 was a companion to Poster Presenta-
tion SI 7, and both are outgrowths of the wastewater treatment research
effort that has consumed the attention and energies of many of the
South African workers during the past eight to ten years, i.e., the
excess biological removal of phosphorus by activated sludge. The
significance of this paper cannot be truly appreciated outside of
the context of the overall efforts, which were thoroughly documented
and discussed at a post-conference symposium held in Pretoria. The
reader is referred to those proceedings which can be obtained from:
The Secretary, Post Conference Seminar on Phosphate Removal in
Biological Treatment Processes, c/o Water Research Commission,
P. 0. Box 824, Pretoria 0001, Republic of South Africa, or IAWPRC
Headquarters.
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About 30 full-scale Bardenpho or Phoredox nutrient-
removal activated sludge plants have been constructed and operated
throughout South Africa. A recent survey, however, showed that very
few of these plants were actually achieving nutrient removal to the
level for which they were designed. In the meantime, research at
the University of Cape Town established that totally anaerobic condi-
tions must precede the aerobic portion of the treatment system for
excess phosphorus removal to occur and this combination was not
typically accomplished by the Bardenpho-Phoredox systems because of
recycle patterns. Three of the plants were subsequently modified
in accordance with the research findings, and excellent phosphorus
removal is now being attained at these facilities. The Cape Town
University researchers also identified a bacterial genus with very
unusual abilities as the primary phosphorus removing organism.
This genus was AcxneXobacXeA and the researchers claimed that
anaerobic conditions preceding the aerobic section give these
bacteria a competitive advantage over other activated sludge
bacteria. Poster Presentation SI8 was the result of research
designed to check the validity of the Cape Town University findings
as was Poster Presentation SI7.
The original thrust of the work was the description of
microbial life as it developed during plant start-up. Nothing
unusual or not already known was revealed by this portion of the
work. The appearance and subsequent development of AcxneXobacXeA
as the dominant bacteria was very significant, however, as was
the demonstration that it was the dominant bacteria at four
separate wastewater treatment plants achieving excess phosphorus
removal. Further indications are that the techniques used actually
underestimated the numbers of AaineXoba.cXeA present. These results,
combined with the results of the Cape Town University researchers
and the demonstration of phosphorus granules in A(UyieXoba.cXeA
(Poster Presentation S17), seems to rather conclusively
establish Ac-tnztobaczeA as the primary microbial agent responsible
for excess phosphorus removal. It should not be ignored, however,
that other organisms such as Uoc-cvuLLa. have also been shown to store
phosphorus. Unfortunately, NocandLa. and its companions frequently
exist in filamentous form and cause poor settling of the activated
sludges in phosphorus removal plants. The respective growth require-
ments of AcXneXobacteA and NocaAcUa need to be carefully studied
and compared to see if operational methods that would encourage
AcuneXobacXeA while discouraging NocaAxUa can be devised. Fila-
mentous growths resulting in poorly settling sludge appears to be
the principal problem remaining in the development of activated
sludge plants that can remove phosphorus concentrations typically
found in domestic sewage down to concentrations of 1.0 mg/l or
less.
The overall merit of Poster Presentation S25 would seem
to be as sound as any diversity index approach. Better definition
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of the extent of nematodes resistance to pollution and the extent
of copepod sensitivity to pollution is needed for more complete
evaluation.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The mechanisms of the contact stabilization activated
sludge process have never been well understood. This has hampered
the development of design formula and has made the use of
laboratory/pilot plant testing essential for determining its
usefulness for specific wastewaters. The results of Yoshimura
and Nakae (Poster Presentation S3) that adsorption on activated
sludge was primarily related to the hydrophobic properties of
the organic chemical may be the key towards a better understanding,
and eventually better design technique, for this biological process.
The high toxicity of polyelectrolytes for aquatic life
indicated that considerable research needs to be performed to deter-
mine the implications of this for the utilization of polyelectrolytes
in water and wastewater treatment plants. For example, when poly-
electrolytes are used to enhance activated sludge settling, what
concentrations escape in the effluent? Can harm to aquatic life
be demonstrated in the streams? The widespread use of polyelectro-
lytes in the United States seemingly indicates that a high priority
should be placed on this type of research.
Research of Spraggs et al. (Canada) (Poster Presenta-
tion SI4) casts extreme doubt on the usefulness of the Microtox
method. This approach did properly rank the relative toxicity of
the chemicals but it showed a grave lack of sensitivity. From their
results, it would appear to have very limited usefulness.
The models developed by Herold (South Africa) (Poster
Presentation S15) should have considerable application in the
United States. They should be directly applicable to western
states where considerable irrigation is used and the build-up
of TDS is a problem. They should be of even greater interest to
those concerned with predicting/controlling pollution from diffuse
sources. With relatively small modifications, it should be possible
to adapt the models for pollutants other than TDS, such as nitrogen,
phosphorus, and heavy metals, all of which are of considerable
concern in numerous urban areas throughout the country.
The work pertaining to excess biological phosphorus
removal (Poster Presentation S18) is of great interest in the
United States in the immediate future and should have far-reaching
effects. The demonstration in South Africa that phosphorus can be
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removed to very low levels by biological methods, without chemical
addition, and that the process can be reliably controlled, should
stimulate interest in such an approach in this country. In fact,
it has already occurred to a significant degree. The establishment
of AcUeXobacteA as the primary biological agent responsible for
the phenomenon should stimulate considerable research towards
developing an understanding of the limitations and capabilities of
the organism, which will provide insights in how to control its
performance during plant operation. Further, the implication of
HocaJuLLa. as a cause of poor settling of nutrient removal sludges
should restimulate research interest in an organism that has
caused serious foaming problems in treatment plants all across the
country.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Effects of Pollutants
on Receiving Waters
II. REVIEWER
A. Name: Herbert C. Preul
B. Position and Affiliation: Professor of Civil and
Environmental Engineering
University of Cincinnati
Mail Location 71
Cininnati, OH 45221
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation SI6: "A Chemical Investigation of
a Marine Sewage Outfall," by
P. D. Bartlett and 6. A. Eagle
(South Africa)
Table Bay, situated in the northern end of the Cape penin-
sula near the southwestern tip of Africa, is bounded on the south
and east by the City of Cape Town and on the north and west by the
Atlantic Ocean. The seabed is mostly rocky with occasional patches
of sediment. The largest sediment accumulations occur close inshore
in the south and southeast. The bottom topography is gentle and
reaches a maximum depth of 35 m on the western side between Robben
Island and Green Point.
The bay receives waste from a number of inputs, notably the
Green Point sewage outfall. Approximately 3 x lO^m^ of raw sewage
are discharged daily via this outfall. The pipeline is about
600 m long and has a single port at a depth of about 17 m. The
other major waste inputs include the Table Bay harbour area and
the Salt River which carry partly treated and other industrial
effluents. This study is being undertaken primarily to determine
the behavior of sewage from a single outfall (Green Point) on entering
the sea. The contribution of this effluent to the overall chemical
budget of Table Bay, including nutrients and trace metals, is being
examined. Studies of water chemistry, sediment chemistry and biology,
have been undertaken to complement physical oceanographic studies
carried out previously.
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Forty-five sampling stations were set up in the bay.
Contour maps have been prepared with a computer package to display
the distribution of the various chemical parameters. Typical
residence time of water in the bay is two-three days. The contour
maps showed clear plumes for many of the measured parameters ex-
tending from the outfall. The shape of the plume depended on the
wind regime at the time of sampling. After calm weather, higher
concentrations were found close to the shore, while after a south-
easterly wind, the plumes extended from the outall towards the
middle of the bay. The areas of high nutrient and trace metal
concentrations corresponded with the areas of depleted dissolved
oxygen. Degradation of the sewage thus leads to lower oxygen
levels in the water. The source of these species could be either
upwelling or a bottom current flowing in the opposite direction
from that indicating a likely atmospheric input.
The highest concentrations of all the trace metals
studied in the sediments were in the Granger Bay-harbor entrance
area. These high levels did not correlate well with particle size
or organic content and it is not yet clear whether these metals
originate from the sewage.
Estimates have been made to assess the mass of nutrients
being carried into and out of the bay. In all cases, there was
a net removal of nutrients from the water within the bay. In view
of the vast amounts of nutrients introduced into the bay through
the upwelling process, it is likely that the contribution from
the sewage outfall will be relatively insignificant.
A similar calculation concerning transport of metals into
and out of the bay has been performed. Allowing for the wide margin
of error in such calculations, there was excess iron and lead leaving
the bay whereas more zinc was being introduced than lost.
These results represent the first part of a long-term study
to assess the impact of sewage and other effluents on an area such
as Table Bay. In particular, budget calculations will be attempted
to try and ascertain the long-term effects, if any, of sewage dis-
posal in coastal areas.
B. Poster Presentation SI9: "Nutrient-Salinity Relationships
in Four Estuaries of the Cape
Province, South Africa," by
G. A. Eagle and P. D. Bartlett
(South Africa)
In order to predict the behavior of pollutants in estuaries,
it is essential that the chemistry of unpolluted estuaries be better
understood. For this reason, four estuaries in the Cape Province
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have been studied, with the aim of understanding the concentration
gradients which occur for various chemical species in the transition
from freshwater to seawater.
The estuaries studied were the Orange, Olifants, Berg,
and Breede. All are relatively unpolluted except for agricultural
runoff. The mouth of the Berg River has been modified by the con-
struction of breakwaters, but the other estuary mouths are still
in their natural states.
The general behavior of nutrients in estuaries has been
established in a number of studies and results have been summarized.
However, to date, no similar work has been done in South African
estuaries. This poster described the work carried out and includes
some results which are significantly different from normally expected
concentration gradients including the following: (1) Salinity. The
degree of penetration of saltwater into the estuaries was found to be
far more dependent on river flow than on tides. It appeared that
the mixing of salt- and freshwater can take place anywhere in the
lower, approximately 25 km of these estuaries, depending primarily
on river flow, but to a lesser extent on tides; (2) Nitrate. The
distribution and levels of dissolved nitrate indicated two major
nitrate sources were land runoff and upwelled marine water. The
relative importance of each process depended on local conditions and
season. (3) Phosphate. Phosphate concentrations in estuaries normally
remain more or less constant due to some form of buffering mechanism;
this was found in most cases in this study. (4) Silicate. In most
cases, the expected inverse linear relationship between silicate
concentration and salinity was observed. (5) Dissolved oxygen. The
dissolved oxygen concentrations in all the rivers were close to the
theoretical saturation levels.
As an overall conclusion, the four rivers all showed
distinct differences from each other and there were also some
differences from the normally expected behavior of nutrients in
estuaries. These differences are being investigated further.
C. Poster Presentation S20: "The Role of DOC and TOH
Measurements in Water Pollution,"
by R. A. Van Steenderen
(South Africa)
The beneficial effects of water chlorination as a means of
safeguarding potable water supplies against bacterial and viral
contamination are still virtually unsurpassable. However, relatively
recent findings have established that chlorination of most surface
waters gives rise to the formation of undesirable halogenated organic
compounds, of which chloroform is the most predominant.
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A highly successful unit process which has become an
integral part of water purification is that of active carbon
adsorption which serves as a final polishing step to remove
color and odors but which also reduces the amount of organic
compounds, including halogenated organic precursors, in the final
water.
The organic capacity of active carbon is, however, not
unlimited and periodic assessments are required to determine its
condition and effective life span. Besides the standard and
lengthy quality parameters used to determine the life expectancy
of the carbon itself, an alternative and less complicated
method is that of monitoring the quality of the outflow of the car-
bon column in terms of parameters such as dissolved organic
carbon (DOC) and total organo-halogens (TOH). The tremendous pro-
gress in development of analytical methods for these parameters
has resulted in more efficient group detection techniques, lower
detection limits and increased analysis rates.
Pilot plant studies whereby activated sludge plant
effluent was passed through columns containing Filtrasorb 300
active carbon illustrated that regular DOC measurements could
serve as early indications of carbon column 'breakthrough.'
Ultraviolet absorbance (4-cm path length at 275 nm) measurements
were usad to indicate a deterioration in carbon conditions, and
because of their simplicity, were suitable as a confirmative test.
A twelve-month survey of Pretoria drinking water found
further application of DOC, TOH and UV absorption measurements
including a relatively new concept called the total organo-halogen
potential (TOHp) value, whereby samples were overchlorinated to
100 mg/£ in the laboratory and left for 48 hours before analysis.
Statistical evaluations showed that with the exception of TOH,
positive intercorrelations existed between DOC, TOHp, and UV
absorption measurements for a specific water. The significance
of these correlations was dependent on water quality consistency
and the correlation between DOC and UV absorbance was seasonably
dependent.
D. Poster Presentation S24: "The Impact of of Diffuse
Atmospheric Nutrient Loading
on an Oligotrophic Freshwater
Lake in a Developing Urban and
Industrial Area (Richards Bay,
South Africa)," by C. G. S.
Archibald and M. S. Muller
(South Africa)
Significant increases in urbanization and industrialization
occurred from 1964 to 1981 in the catchment and Richards Bay area.
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Atmospheric fallout of total nitrogen increased over this period.
Increases in algal growths in the spring and summer have caused
water treatment problems with commensurate increases in costs.
Corrective steps taken in the treatment plant included the addition
of dissolved air flotation and improved filtration procedures.
E. Poster Presentation S30: "The Measurement of Organic
Pollution of the Sea Using
Satellite Imagery," by
L. V. Shannon, N. M. Walters,
and A. G. S. Moldan (South Africa)
During the austral summer of 1978-79 and 1979-80, a series
of ocean color experiments were undertaken in the southern Benquela
current region off South Africa. The objective of the experiments
was to relate the Coastal Zone Color Scanner radiance measurements
from the NIMBUS-7 satellite to chlorophyll (phytoplankton) distribu-
tion, to organic pollution emanating from the fish processing fac-
tories in the St. Helena Bay area and to the dynamics of the fronts
associated with the upwelling system. The Coastal Zone Color
Scanner (CZCS) is a six-channel scanning radiometer with four
channels in the visible 443, 520, 550 and 670 nm, one in the near
infra-red at 750 nm and one in the infra-red at 11.5 um.
Extensive and intensive ground truth observations were
made to validate the results obtained from satellite imagery and
a good correlation was found between the chlorophyll concentrations
deduced from the latter and direct measurements in 4-c£u.
The concept of using satellite imagery is not new. The
main problem with satellite observations is that, unless there are
good ground truth data to support these measurements, the inter-
pretation must remain suspect.
IV. CRITIQUE OF SESSION
The poster presentations were concentrated on the effects
of chemical and organic pollution due to wastewaters. Particular
study and emphasis was given to the effects of nutrients such as
various forms of nitrogen and phosphate. New techniques and
approaches in monitoring have been demonstrated, e.g., satellite
imagery of organic pollution in outfall waters.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The reported results in this session are seen as being
pertinent to United States needs in the form of approaches for
monitoring water quality. Several of the nutrient studies ex-
tended over a number of years of study (e.g., Poster Presentation
S24), and the results certainly can provide important insights
where developing urban and industrial areas are affecting bodies
of water which are important water supplies.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Oil Spills and
Environmental Pollution
II. REVIEWER
A. Name: Thomas H. Goodgame
B. Position and Affiliation: Director, Corporate
Environmental Control
Whirlpool Corporation
Benton Harbon, MI 490222
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation S7: "Total Mercury Concentrations
in Some Species of South African
Commercial Marine Fish," by
J. Henry (South Africa)
Results of the analysis for mercury for sixteen species of
fish, native to the South African coastal waters, and primarily from
the western or South Atlantic, coast were presented. The range of
mercury concentrations was from less tha 0.03 to 0.36 ug/g with the
lower limit of the analytical technique being 0.03 ug/g and the
mean for all of the determinations being 0.11 yg/g. Data for a
world mean for fish species was indicated to be about 0.13 pg/g.
On this basis, it was concluded that fish mercury concentrations
were similar to concentrations reported in other areas, and were
therefore "natural."
B. Poster Presentation S8: "Toxicity Testing of Oil Spill
Dispersants," by A. Moldan and
P. Chapman (South Africa)
A bioassay test used to screen oil dispersing agents for
use in a marine environment was described. Using crude oil as a
control, the percentage of subjects that die with the dispersant
added to the crude oil/water system are compared. Under normal
conditions, 40% of the test specimens would die. If the percentage
that die with the oil dispersant added to the system does not exceed
50%, the dispersing agent is passed for use. Usually there were
significantly more survivors after oil treated with dispersant
versus no dispersant. A number of commercial oil dispersing agents
have already been screened and passed for use.
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C. Poster Presentation S9: "Effects of Oil on Reproductive
Capacity of CcUJUmcuia fvuuu>A
-------
agent was reported to do a good job of producing a solid gel, but
it appeared to add dissolved organic carbon to the sea water.
IV. CRITIQUE OF SESSION
Poster Presentation S7 dealt with mercury content of
commercial marine fish in South African waters. This paper was
of very limited interest.
Poster Presentations S8 and S29 dealt with methods for
cleaning up or dispersing oil spills. These were both well
prepared posters. The explanations were clear and useful to one
interested in the field.
Poster Presentations S9 and S28 dealt with aspects of
the effects of crude oil (petroleum) on marine life. Both these
posters form a portion of the Ph.D. theses of the authors. The
authors were frequently in attendance and were very willing and
capable in answering questions and responding to comments.
Poster Presentation 10 dealt with the use of ultra-
violet absorption for analysis of wastewater from fish factories
and was highly specialized dealing with the analytical techniques
only.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Significant methods of controlling oil spills
evaluating oil spill clean-up agents were presented. There is
a continuing need in this area and the methods given in Poster
Presentation S8 are already in use in South Africa. While the
test results appeared to be crude, they did give useful and usable
results. Poster Presentations S7, S9 and S28 were particular to
species of South African waters and may be generally applicable
elsewhere. The information developed in Poster Presentation S7
will generally add to the data base for mercury levels throughout
the world. The methodology presented in Poster Presentation S10
was specific to a particular location. However, the method of
ultraviolet absorption might usefully be transferred to locations
that might be of more interest in our fisheries industry and in
waters receiving wastes from meat and fowl processing locations.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Wastewater Treatment
II. REVIEWER
A. Name: Robert A. Canham
B. Position and Affiliation: Executive Director
Water Pollution Control
Federation
Washington, D.C.
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation S2: "Computer Control in a Sewage
Plant, Methods and Experience," by
C. P. Kuznia (Federal Republic
of Germany)
This was a concise and well-presented pictorial and
graphical display of an integrated computer application for opera-
tional control of a small treatment plant in Germany. The computer
system had a voice component which appeared to be the only unique
feature. It would not be expected that there would be any particu-
lar difficulty in applying the same principles to treatment plant
control in the United States or elsewhere. No information was
available on how long it took to develop the software, at what
cost the system was installed and operated, nor what functional
problems have been experienced.
B. Poster Presentation SI7: "The Location and Nature of
Accumulated Phosphorous in
Activated Sludge," by
L. Buchan (South Africa)
This laboratory study made some positive statements but
also left some questions. The author confirmed the importance of
A(UneXobacXeA species in the phosphorus removal process in activated
sludge. The work also concluded that the nature of the carbon
source in the substrate has a profound influence on the amount of
phosphorus accumulated. The author did not draw a conclusion
relative to whether the role of the anaerobic zone in a nutrient
removing activated sludge plant is to subject bacteria to stress
or to provide phosphate accumulators with the necessary substrate
to ensure their continued growth.
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C. Poster Presentation S23: "Influence of Sewage
Irrigation on the Groundwater
Quality," by G. Milde, H. Dizer,
Z. Filip, V. Newmayer, and
V. Paibyl *
This poster presented in tabular and graphical form a
series of groundwater data that the authors claimed supported
their conclusion that there has been no significant degradation
of groundwater quality during the 80-year history of applying
sewage to land. There was no evidence of innovative work in the
report.
D. Poster Presentation S32: "Precipitation of Calcium
Phosphate and pH-Effects in
Denitrifying Biofilms," by
E. Arvin and G. H. Kristensen
(Denmark)
An excellent summary brochure accompanied this poster.
This type brochure would be a good sample to use as guidance for
those preparing posters. In less than five minutes, a viewer of
the poster and reader of the brochure can tell what the work was,
the basic premises, methods, results, and conclusions. For those
with special interests in phosphorus removal, further discussion
with the authors is encouraged. There was no evidence that this
laboratory work has been extended to either pilot- or full-scale
work.
E. Poster Presentation S33: "Biochemical Changes Associated
with Luxury Phosphate Uptake
in a Modified Phoredox Activated
Sludge System," by D. J. J.
Potgieter and B. W. Evans
(South Africa)
This poster related to work done on a commercial process
for phosphorus removal. The process appears to be similar to the
patented Phostrip Process in the United States. The poster described
a bench-scale project and the state observations from the work were
as follows: (1) increased amino acid content occurred during good
P-removal, and (2) concurrent release of P, Mg++, and Ca++ occurred.
The authors did not relate the observations to application and the
circumstances that caused "good" P-removal were not discussed.
F. Poster Presentation S34: "L.F.B. - Full Scale
Operation," by D. S. Render
(South Africa)
This describes an apparent commercial process that incor-
porates the full range of physical, chemical and biological unit
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processes used in advanced waste treatment. For example, chemical
(organic) flocculation, other flocculants, multimedia filtration,
and carbon filtration were included. The application has been in
treating complex industrial wastes. Extremely high degrees of
removal of organic and heavy metals were shown in the tabular form
but the composition of the raw wastes was not specified. The pro-
cesses used were those of accepted technology.
IV. CRITIQUE OF SESSION
Poster presentations are generally hampered in their
effectiveness by the limited space available for presentation
and by the nonavailability of the authors during the posted times.
Summary brochures to accompany the posters would be very helpful
in providing additional information.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Research activities in South Africa have begun to elucidate
the mechanisms involved in luxury phosphorus uptake. With this
understanding, they have begun to develop and apply this technology
on a full-scale basis which optimizes this process. Closer examination
of this fc'ork by United States engineers and equipment vendors is
suggested.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Wastewater Treatment
II. REVIEWER
A. Name: K. Daniel Linstedt
B. Position and Affiliation: Project Manager
Black and Veatch Consulting
Engineers
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation S35: "Suppression of Density Waves
in Clarifiers," by M. C. Murphy,
R. R. Hudgins, and P. L.
Silverston (Canada)
Experiments on 1.2-m diameter model clarifier operating
at overflow rates and suspension concentrations corresponding to
municipal treatment practice showed that baffles, designed to function
as wave traps, suppressed low-frequency, large-amplitude density
waves observed in these units. Simultaneous measurements of solids
removal show substantial improvement. This work established the
relationship between density waves and the deviation from ideal
clarifier performance that earlier papers on internal waves from
this research group suggested. The power spectrum of the internal
waves and the effect of operating variables, such as overflow rate,
scraper speed, and suspended solids, on the spectrum and solids
removal were discussed.
B. Poster Presentation S36: "Parasites in Southern United
States Sludges and Disinfection
by Standard Sludge Treatment,"
by R. S. Reismers, M. D. Little,
A. J. Englande, D. B. Leftwich,
D. D. Bowman, and R. F. Wilkinson
(U.S.A.)
The objectives of this study were to: (1) assess the
presence and densities of resistant stages of parasites in municipal
wastewater sludge (sewage) in the southern United States; (2) inves-
tigate parasite inactivation by lime treatment of sludges seeded with
intestinal parasites; (3) measure the mass balance of helminth eggs
through various processes in a municipal wastewater treatment plant;
and (4) assess, on the basis of laboratory and field data, standard
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sewage sludge treatment processes for their effectiveness in
inactivating parasites.
Sludge samples collected during each of the four seasons
from 27 municipal wastewater plants located in Alabama, Florida,
Mississippi, Louisiana, and Texas were examined for the presence
and densities of resistance stages of human and animal parasites
using parasitologic techniques developed for this study. Viable
eggs of A&c.arU& and Toxocana were recovered at least once from
every plant and viable eggs of TAAckustsU vulpU and THMihuJuA
t/uxikiuAa. were recovered at least once from 26 and 15 plants,
respectively. Viable eggs of at least 10 other helminths and cysts
of a few protozoa were also found in fewer numbers and less fre-
quently. Depending upon the parasite, the inactivation of para-
sites during sewage treatment fluctuated from season to season,
but, in general, most were inactivated in the summer. Laboratory
studies verified the results of previous investigations indicating
that destruction of resistant parasite eggs is primarily due to
temperature (heat) and not to a specific digestion process. Very
large lime doses were required for the inactivation of viable
A&c.(Vlu in sludges and results were not always consistent. Lime
treatment thus appears to be an inexpensive but unreliable treat-
ment for AaccvUa inactivation. Laboratory experiments also showed
that at certain combinations of ultrasonic frequency intensity
and exposure time, Toxotana eggs could be destroyed, but that the
same ultrasonic conditions did not affect A&cculU eggs.
An important finding of this study is the poor suitability
of A&c(Vua eggs taken from the uteri of gravid female worms as
indicators of the characteristics of AacoaXa eggs discharged in the
feces of the host. The eggs removed from the gravid females are
not as resistant to adverse factors as eggs that have undergone
a hardening process in the intestines of the host and been recovered
from the feces.
C. Poster Presentation S37: "Water and Wastewater Treat-
ment with Reusable Magnetite
Particles," by N. J. Anderson,
B. A. Bolto, D. R. Dixon,
L. 0. Kolarik, A. J. Priestley,
and W. G. C. Raper (Australia)
A process was described which used finely-divided mag-
netite particles to adsorb negatively charged colloidal material.
The basic advantages of the process, as compared with the conventional
alum process, are its relative speed and simplicity. By adsorbing
colloidal material directly onto the surface of a charged particle
which can be rapidly removed from the water, the slow processes of
floe growth and sedimentation can be avoided. Also, because of the
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high quality water which can be produced from the clarifier, there
is no need for a subsequent filtration step.
The direct filtration process also avoids the slow floe
growth and sedimentation steps and has some similarities with the
magnetite process. Both involve charge neutralization and adsorp-
tion onto a particle surface. However, in the magnetite process,
the particles perform a large fraction of the charge neutralization
and are suspended in the liquid medium rather than being held in
a fixed bed. This allows the particles to be continuously recovered,
regenerated and reused, thus effectively creating a continuous
filtration process. Consequently, the magnetite process is better
able to handle the more turbid or colored waters which cause
excessively short filter runs in a direct filter.
While the initial application of the process has been
in the field of potable water, treatment of various industrial
effluent has also been investigated. Satisfactory treatment was
obtained in many cases and the magnetite particles were also able
to adsorb phosphate anions, bacteria and viruses.
Research is continuing into the thermodynamics and kinetics
of the interaction of various colloids with the magnetite surface
in the anticipation that this will lead to further process improve-
ments.
D. Poster Presentation S38: "A System Developed for the
Treatment of Tanning and
Fellmongery Effluents," by
S. D. Roets (South Africa)
When Silverton Tannery decided to implement treatment on a
full scale, it was decided to use flotation as a basis for further
development of a system to obtain ultimate solid separation with
minimum costs. As difficulties in several pilot plants developed
regarding the control and implementation of dissolved air flotation,
it was decided to experiment on the abandonment of dissolved air and
pursue full-scale operation using foam flotation. A new concept
called the Silflo System was introduced whereby some 20% of the clear
effluent of the flotation unit was recycled for the production of
foam. The foam is generated as a result of the mixing of air with
an acidified effluent containing proteinaceous material. The
addition of an acid was either in the form of a salt like ferric
chloride or aluminum sulfate, or in the form of a liquid acid.
Chemical addition not only precipitated the proteinaceous material,
which was subsequently removed along with the other solids like hair
fleshings, shavings and chrome particles, but also assisted in the
production of a stable foam which acted as a support for these
solids. A cationic polymer was added in the same line as the acid
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and foam to render the sludge hydrophobic so that interstitial water
was released while the solids floated to the surface. The mixing
of the foam and the polymer were achieved in the delivery line from
a Mono pump supplying wastewater to the flotation unit. This made
additional flocculation and coagulation facilities unnecessary.
The process was particularly effective for the treatment
of tannery wastewater but could be extended to treat other types of
effluents as well. Preliminary investigation showed promise in
treating wastewater from abattoirs, chicken processing, general
meat processing, paper mills, wetblue plants and fell mongeries.
The COD, solids, sulfide and chromium in tannery wastewater
can be reduced in excess of 90%.
E. Poster Presentation S39: "Research into Mass Culture
of Algae in Closed Systems,"
by R. D. Walmsley,
S. N. Shillinglaw, and
D. Geldenhuys (South Africa)
In order to investigate the scaling up of algal cultures
from the laboratory to the outdoors, some of the early work on mass
algal culture involved the use of systems which were closed to the
atmosphere. However, because nearly the entire work on algal mass
cultures was restricted to open ponds, developments of closed systems
over the past 30 years have been limited. The commercial exploita-
tion of algal cultures is dependent on their integration into multi-
use systems or utilization to solve environmental problems. In
view of the possible benefits of linking closed algal culture systems
with ethanol fermentation units, an evaluation of the concept of
algal cultures in closed systems was presented as well as some
design considerations for experimental ponds to be used in investi-
gation of the feasibility of such a practice under South African
conditions.
F. Poster Presesentation S40: "Utilization of Computerized
Water Monitoring and Information
Systems," by E. Ottmann (Federal)
Republic of Germany)
In many countries automated water monitoring systems are
installed and interesting reports have been published specifying
required instrumentation, telemetering, and data acquisition and
handling systems. Questions arise concerning the philosophy and
the utilization of the equipment. Computerized water monitoring
and information systems may serve several purposes including:
providing data for hydrological services; improving the availability
of data; enabling actual use and interactive communication and con-
trol; providing information for special tasks such as modeling
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prediction of various operations, monitoring conditions on over-
loaded rivers, or inspecting the performance of treatment plants
and comparing this performance with the requirements of state or
national laws. The resulting benefits in operation should be set
against the costs of installation and the advantages of continuous
measurement of parameters.
In hydrology, a description of the dynamic behavior of
a water body and the associated water quality is needed. More
specifically, supervision and control of automatically-merged
information is necessary. It is now beginning to be appreciated
that there are many tasks that cannot be fulfilled without the
help of automation and computers. Besides the current and auto-
matically sensed parameters, data must be integrated after sampling,
lab analysis, and manual keyboard-input and must be considered as
a whole for the purposes of management. Data acquisition may show
how to differentiate between the various parts of a measurement
network. Automated methods represent a small part of that total
effort.
The monitoring network developed in Bavaria during the
last five years utilizes a computerized information system that
collects data from widely scattered points on rivers and offers
evaluated information for users. Control of the automated system
is carried out regularly by a process computer connected to field
stations in Bavaria via dial-link lines of the public telephone
network and with special parallel-serial codes. Reverse communica-
tion is available for remote controlling.
Automatic data acquisition from the field stations and
the data input by teletransmission or keyboard provide the input
to the system; on the other side is the output for users. The
headquarters—a computer center—has to gather, prepare, calculate,
and evaluate all the data before they are stored,for example, on
disks and tapes. Users are then able to obtain all offered informa-
tion and computer printouts or displays for any application from
interactive graphic terminals. The defined objective of the system
is information and communication, not merely water monitoring.
IV. CRITIQUE OF SESSION
The authors of Poster Presentation S35 presented an
interesting paper dealing with the nonideality of settling in clarifiers.
However, some of the conditions imposed in the model system limited
the extent to which their results can be extrapolated to predict per-
formance of the suggested improvements on full-scale clarification
systems. The 1.2-m diameter clarifier size likely accentuated some
of the hydraulic problems that exist in larger clarifiers. Addi-
tionally, a non-flocculating suspension in the concentration range
300-5000 mg/I was used to monitor settling performance.
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At influent concentrations of 1000 mg11 and higher,
the impact of the baffles was inconclusive over the range of
reasonable overflow rates. Generally, the settling efficiency
was lower than that typically experienced in practice, even though
wind and thermal currents evidently were minimized in the experi-
mentation. It appeared that adequate pilot-scale work has been
performed in evaluating the proposed wave-trap baffling system.
Detailed investigation of full-scale operating clarifiers should
now be performed to verify the impact of the baffling system in
improving clarifier performance.
A topic of significant practical value in the United
States, because of the increasing trend toward land disposal of
wastewater sludges was included in Poster Presentation S36. The
approach followed a thorough and logical pattern that included
the development of new separation and analytical techniques, and
the application of those techniques to enumerating parasite densities
in sludges. The sludges studies covered a spectrum of major sludge
treatment approaches that are representative of typical practice
in the United States. The study confirmed the resistant nature of
parasites to these sludge treatment processes. It would be of
interest to expand the scope of the study to include additional
climatic regions and some other treatment methods, such as com-
posting, that may be employed in conjunction with land application.
The process discussed in Poster Presentation S37 offered
an intriguing alternative to conventional water clarification
practice. By using a solid material to remove suspended material
and color, the clarification process can theoretically proceed much
more quickly and result in much lower solids quantities requiring
ultimate disposal than with chemical coagulants. However, there
appeared to be significant shortcomings to the process. Perhaps
most important in the treatment of supply waters is the limitation
on treatment efficiency. It appeared that the proposed process will
not achieve acceptable product water color and turbidity levels in
many instances. Additionally, it appeared that the critical
magnetite-washing step may be difficult, particularly in wastewater
applications. Finally, there is a definite tradeoff between reduced
capital costs and increased power costs when this process is com-
pared to conventional chemical clarification practice. This tradeoff
needs to be evaluated very carefully in the context of life-cycle
costing because of the escalation accompanying energy charges.
Poster Presentation S38 presented an interesting approach
for pretreatment of selected industrial wastes that have high sus-
pended solid and organic concentrations. The modified foam flota-
tion process appeared to provide substantially better suspended
solids removal than either gravity sedimentation or dissolved air
flotation at the solids concentrations associated with the industrial
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wastes under study. However, a discussion of the mechanisms con-
trolling the process was limited. As such, it is impossible to
identify the parameters dictating process performance and to deter-
mine the approach to designing the process for treating wastes of
differing constituent characteristics. More information is necessary
relative to the range of variables evaluated and their impact on the
efficiency of the treatment method.
An interesting assessment of an approach to maximizing
a closed algal cultural system was presented in Poster Presenta-
tion S39. The system was designed to utilize an industrial
CO2 source, minimize evaporation, facilitate recovery of 0? as a
byproduct, and recycle the algal biomass to produce ethanol and
protein for an animal feed supplement.
It was determined during the course of the research that
closed systems have some drawbacks related to decreased light
supply and high temperatures that develop. The reduced productivity
associated with these system characteristics will have to be resolved
if this type of system is to be practical, given the high capital
cost relative to that of open systems.
Poster Presentation S40 described a specific circumstance
involving the utilization of a computerized data collection and
transmission system. While the system successfully addressed some
historic communication problems related to Bavarian water resources,
it did not appear to offer major new conceptual insights relative
to data management.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
A relatively low-cost physical modification to wastewater
clarifiers that would improve efficiency or facilitate higher
hydraulic loadings would be a valuable improvement. The capability
of the proposed system described in Poster Presentation S35 for
achieving these goals has yet to be demonstrated.
The results of the study in Poster Presentation S36
are of immediate significance to American sludge disposal practice
and should be expanded to cover a broader scope of conditions and
practices throughout the country.
The magnetite process described in Poster Presentation
S37 appeared to be undergoing continual refinement to address
some of the indicated drawbacks and to expand the range of process
applications. With additional process improvements, there may be
some instance where this technology would be useful in the United
States. However, it is doubtful that this process will revolutionize
American clarification practice.
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The problem addressed in Poster Presentation S38 is
one that is common to the industrial sector in the United States.
With the results and cost information presented, the proposed
process warrants further investigation. It could provide another
viable pretreatment alternative for a number of major American
industries.
The specific application of algal cultural development
pursued in Poster Presentation S39 has limited potential for
impacting American water polluton control practice. Further, the
concept of closed algal culture systems appeared to have several
costly drawbacks that negate the potential benefits addressed
in the research. Poster Presentation S40 does not appear to
provide much new input to American water pollution control practice.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Wastewater Treatment
and Reclamation
II. REVIEWER
A. Name: Bruce A. Bell
B. Position and Affiliation: Professor of Engineering
George Washington University
School of Engineering and
Applied Sciences
Washington, D.C. 20052
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation S5: "Flotation as the Final Clarifi-
cation Step in Wastewater
Treatment and its Influence on
the Oxygen Balance of Receiving
Waters," by K. P. Kiefhaber,
U. Neis, and J. Weber (Federal
Republic of Germany)
The poster presented a comparison of dissolved air flota-
tion (DAF) and sedimentation for secondary clarification in a con-
ventional municipal wastewater treatment plant. The poster then
went on to calculate and present the effect of effluent dissolved
oxygen concentration on the oxygen budget in the receiving stream
based on the conventional Streeter-Phelps model.
The mixed liquor from a conventional municipal treatment
facility was fed to parallel pilot-scale secondary clarifer and DAF
units. Although not presented, discussions with Wolf revealed that
the DAF unit was operated at a pressure of four bar at a 50% recycle
of subnatent and without polymer addition. No sizing or operating
parameters were available for the secondary clarifier. The use of
sedimentation resulted in an overall plant BOD5 reduction of 95%,
an effluent turbidity of 5.4 FTU and an effluent dissolved oxygen
concentration of 2.2 mg/£. When DAF was used as the final solids
separation unit, the overall plant BOD5 reduction was 97%, the
effluent turbidity was 3.3 FTU and the effluent dissolved effluent
concentration was 5.2 mg/£. No effluent suspended solids data
were presented.
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The effect of the discharge of the two dissolved oxygen
concentrations resulting from DAF and flotation on the D.O. sag
curve in receiving waters was modeled. As would be expected,
the critical D.O. concentration was higher for DAF than for sedi-
mentation. The time of flow to critical D.O. concentration was
longer for DAF.
Virtually all the calculated effects on the D.O. sag
curve resulted from the higher D.O. concentration in the effluent
from DAF. Since this was pilot-scale work, no verification of the
calculated D.O. effects was available. No data were available
either in the paper or from the authors regarding reliability of
performance or variations in operation of either process.
B. Poster Presentation S6: "The Disposal of Sewage Sludge
by Land Spreading," by J. H. Nell
and J. F. P. Engelbrecht (South
Africa)
An overview of current land spreading practices and
regulations in South Africa was presented as was a summary of current
research into the effect of sludge application rates on metals
and pathogen contents of crops grown and leachate. Land spreading
is the major form of sludge disposal in South Africa. Of concern
are heavy metals and pathogenic organisms. The paper summarized
the regulations which use as a philosophical base the concept that
sludge which contains no E. aoti, Aacciaaa lumbnAxio^d
-------
C. Poster Presentation S21:
"Aspects of the Performance
of Final Clarifiers in the
Activated Sludge Process," by
C. Davies (South Africa)
Several concepts in the design, monitoring and operation of
secondary clarifiers in activated sludge plants was presented. The
ideas presented were based on a combination of field trouble-shooting
of clarifiers as well as full-scale experimentation on plants ranging
from 1000 m3/d to 150,000 m^/d. All plants studied had anoxic or
anaerobic zones for biological nitrogen or phosphorus removal.
The author recommended design be based on solids flux as
well as overflow rate and that a flux of 6 kg/m2- hr is a safe peak
design flux. Also recommended is a minimum 3-m sidewater depth.
The author stated that poor inlet design can cause constant failures.
Inlet designs which contain a forced change in direction of flow
were recommended. It was also indicated that care must be taken
to ensure that the gap between scum baffles and launders must be
sufficient to avoid high local velocities. A minimum of 400 mm
between the baffle and launder was recommended.
The SVI test was found to be of little value due to lack
of stirring and wall effects. It was recommended that the initial
settling velocity of the sludge be obtained by turning off aeration
equipment for a short period of time and observing the rate of
blanket settling. Data were presented showing that return sludge
ratio has a profound effect on thickening with a recommended range
of 0.5 & RAS ratio * 4.0.
D. Poster Presentation S26: "Production of Algal Protein
in Raw Sewage," by J. M. P.
Viviers, E. Sandbank,
L. R. J. van Vuuren, and A.
Gerber (South Africa)
The work gives a superficial overview of work carried
out in harvesting of algae from lagoons and drying of the product
to produce a high protein animal feed. Harvesting of algae from
treatment lagoons was carried out using dissolved air flotation
(DAF) with alum and polymers. No data were presented or available
through discussions with the author regarding DAF design or operation.
The float was then dewatered with centrifugation and air drying.
Again, no process design or operational parameters were available for
these operations. The dried product was low in moisture (<10%) and
ash (<10%) and contained 55% protein. Feeding tests are in progress
with no results yet available.
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E. Poster Presentation $31: "Exhaustive Recyclic Use of Water
in the Food Industries," by
R. A. Gallop, A. W. Hydamaka,
B. J. Clark, and L. B. Carvalho
(Canada)
The poster presentation presents virtually no data or
current research. Rather, the authors present an argument for
reuse of water in the food processing industry, particularly in
the third world. Examples of reuse in the food industry were
presented with particular emphasis on cascade processes where
water was used from the last back to the first operation on the
processing line.
IV. CRITIQUE OF SESSION
Poster Presentation S5 was focused on the effect of
effluent dissolved oxygen concentration on the stream sag curve
as calculated by the Streeter-Phelps model. There was no vali-
dation of predicted results.
Poster Presentation S6 presented an interesting overview
of the practice and philosophy of land spreading of sludges. It
is interesting to note that the authors expect a relaxation in the
requirements as a result of current research. Research currently
in progress indicated that only some parameters in leachate and
plants can be correlated to sludge application rates. This is an
area which should continue to be of research interest.
Poster Presentation S21 was excellent and was based on
full-scale experience of design, monitoring and operation of
secondary clarifiers. The value of the work is limited by the
fact that only plants containing anoxic or anaerobic zones were
studied. However, discussion with the author who was totally
conversant with the subject helped extend the work beyond that
formally presented.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
Poster Presentation S5 raised a question which may be of
interest to American researchers. Investigations into the cost
effectiveness and benefits of DAF as a secondary solids separation
process as opposed to sedimentation and reaeration for oxygen
limited receiving waters may be beneficial.
Data presented in Poster Presentation S6 showing only
partial dependence of leachate and plant qualities on sludge appli-
cation rate offered opportunities for additional research. Also,
the philosophical basis for land spreading regulation should be
of interest.
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Poster Presentation S21 points out very clearly the
lack of knowledge regarding design, operation and monitoring
of secondary clarifiers. Much work is needed in this area in
order to provide design engineers and operators with useful infor-
mation and procedures.
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I. SESSION
A. Day: March 29 to April 2, 1982
Hall: Civic Center
B. Theme of Poster Presentations: Membrane Processes;
Environmental Microbiology
II. REVIEWER
A. Name: George Bel fort
B. Position and Affiliation: Department of Chemical and
Environmental Engineering
Rensselaer Polytechnic Institute
Troy, NY
III. DESCRIPTION OF POSTER PRESENTATIONS
A. Poster Presentation S4: "The Application of Pre-
Treatment Procedures to Limit
Membrane Fouling in Reverse
Osmosis Reclamation of Secondary
Sewage Effluents," by
H. A. de Villiers, G. R. Botha,
and M. H. Wright (South Africa)
The authors reviewed the experience of the South Africa
CSIR in operating a reverse osmosis pilot plant on sea water in
Swokopmund, South West Africa (also called Namibia in the United
Nations). Although they were not able to pinpoint the type of
foulant resulting in significant flux-decline during operation,
they discover a novel pretreatment method for reducing the degrada-
tive effects of this fouling. By allowing the feed to remain for
several days in an open reservoir they discovered that membrane
fouling was reduced. They qualitatively attribute this to UV-
degradation together with possible biodegration. This pretreatment
method, called the UVOX process, is now being intensely studied at
the CSIR's National Water Research Laboratory in Pretoria.
B. Poster Presentation SI 1: "The Survival of Bacterial
Indicators in Lysimeters and
Landfills," by J. A. Donnelly,
P. V. Scarpino, and D. Brunner
(U.S.A.)
Data were presented on recovery of feed indicator bacteria
from a 9-year-old commercial municipal refuse landfill and two 2-year-
old lysimeters, one with municipal refuse and the other with hospital
refuse. Total and fecal coliform and fecal streptococci were found
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in homogenized landfilled waste even though fecal coliforms and
streptococci had disappeared two years earlier from leachate
samples. It appeared that neutral pH values in the landfill pro-
vided favorable conditions for survival of the fecal bacteria
since they were present in reduced numbers as the pH decreased
from 7.1 to 5.2 with depth in the landfill. A number of Gram-negative
rods were isolated.
C. Poster Presentation SI2: "The Effect of Ionic Presence
on Chlorine Disinfection of
Animal Viruses," by S. Cronier,
P. V. Scarpino, C. Wells
(U.S.A.)
Information was presented on the influence of potassium
and sodium on poliovirus I and Coxsackie A9 inactivation with free
chlorine at pH 6 and 10 in the presence of several buffers. Data
were also presented on these effects with combined chlorine. The
amount of the inactivation at constant time and nearly constant
residuals depended upon the amount and type of ion and the time of
addition of the ion. These effects were noted for poliovirus I
when hypochlorous acid, hypochlorite ion, monochloramine and
dichloramine were used as disinfectants.
D. Poster Presentation S27; "The Enumeration of Strepto-
cocci and Mycobacteria Present
in Landfill Leachate," by
J. A. Donnelly, P. V. Scarpino
and D. Brunner (U.S.A.)
Qualitative data were presented on recovery of strepto-
cocci and mycobacteria from leachate from a commercial landfill,
pilot and benchscale lysimeters. These had received either municipal
refuse, mixed refuse and sewage sludge or mixed hospital and municipal
waste. Mycobacteria concentrations varied from 1/100 m£ to 33/100 ml
of leachate with eight groups found in at least one sample. A variety
of streptococci were found but with less species diversity in older
landfills indicating a die-off of some strains.
IV. CRITIQUE OF SESSION
Poster Presentations Sll and S27 dealt with a similar problem--
microorganism survival in sanitary landfill. Similar data have been
presented from other studies in the United States. The mycobacteria
findings may be new but were not unexpected. The authors did not
state from which waste these mycobacteria were isolated. The brevity
required in posters precludes the presentation of sufficient data to
answer many of the questions which arise.
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It appeared that all, or nearly all, of the data in
Poster Presentation SI2 have been presented in other papers.
These data, while real, have not been shown to be much more than
a laboratory curiosity. The salt concentrations of interest in
these studies are beyond the range usually experienced in water
disinfection practice. It would seem useful to attempt to deter-
mine the mechanism which causes this effect. If this were known
it would then be possible to extrapolate the known data to other
situations without the need to do another study.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
The information in Poster Presentations Sll and S27 rein-
forced the known facts on biological hazards from landfill leachates.
These leachates are crude materials and their known pollutional
effects must be considered in developing downstream groundwater
supplies or in locating surface disposal points.
The disinfection data in Poster Presentaton S12 were of
limited application value in the usual situation. Where there are
odd salt conditions in the waste to be handled, it would be well
to consider the phenomenon discussed in this poster.
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CHAPTER III
OVERVIEW OF PERTINENT CONFERENCE DEVELOPMENTS
In this chapter, pertinent developments at the Conference
as reported by individual participants are briefly summarized and
categorized. The chapter represents primarily a summary of
Chapter II. However, the chapter also contains a summary of other
observations made by individual participants regarding international
developments of potential interest to U.S. water pollution researchers
which did not emanate from the formal program of the Conference.
DEVELOPMENTS AT FORMAL SESSIONS
This section highlights the individual reports contained
in the previous chapter by reviewing the more significant obser-
vations and conclusions according to various categories of water
pollution research interest. In each case, comments are identified
by the paper number or workshop title to which the observations
relate. Comments included here may not necessarily be contained in
the formal papers but may have developed from discussions at the
Conference. Paper numbers and workshop titles are included to
facilitate reference to the more extensive analyses of Conference
developments included in Chapter II. By referring to the paper or
workshop of interest in the Table of Contents and Key to Reviews,
the location of the corresponding discussion in Chapter II may be
determined.
Analytical Techniques
Detailed procedures for the measurement of wastewater
phenolic compounds in domestic wastewaters and sludges using
capillary GC/MS/DS techniques were presented (Paper No. 30, U.S.A.).
The use of a thermally-modulated electron capture detector,
i.e., two electron-capture detectors in series with a catalytic
pyrolysis unit, in conjunction with two-dimensional gas chroma-
tography, were presented as an emerging analytical procedure. The
technique was shown to be useful in identifying haloacetylnitriles
and trihalomethanes in drinking water (Paper No. 16, U.S.A.).
A membrane diffusion cell was described for use in moni-
toring for dissolved nitrogen (N2) in environmental waters using a
gas chromatography system (Paper No. 18, Norway, U.S.A.).
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Physical-Chemical Treatment
Chlorine reacted with three different organic bases
in different ways (Paper No. 35, U.S.A.). Current ability to
anticipate reaction products is limited.
Slow sand filtration systems were shown to be effective
means of controlling the cercariae (SckUtoAoma mayi&oni) of
human schistomes (Paper No. 17, U.S.A.)
Ultrafiltration was successfully used to recover PVA
from a textile wastewater following pretreatment using filtra-
tion or centrifugation to remove small fibers (Paper No. 45,
South Africa).
Techniques using a simulated flow cell for the charac-
terization of fouling potential of pressure-driven membrane pro-
cesses was presented. The flow cell was shown to be useful in
predicting fouling characteristics for a reverse osmosis membrane
system (Paper No. 19, U.S.A.).
A magnetic ion exchange resin can be used to demineralize
water and wastewater with a TDS of 500 to 2000 mg11 at an 80%
efficiency. Regeneration of the resin requires only the addition of
low-grade heat for removal of exchanged ions (Paper No. 21,
Australia).
Macroporus resins in a strong cation/weak anion sequence
were used in a continuous counter-current ion exchange process for
demineralization of wastewaters and brackish water (Paper No. 23,
South Africa). The use of magnetic ion exchange resins and the
continuous counter-current ion exchange process have the potential
to eliminate fouling problems associated with reverse osmosis
treatment of wastewater effluent.
Use of ozone prior to slow sand filtration was found to
improve heavy metal removal in the filter (Paper No. 37, France).
It was speculated that ozone solubilizes particulate metals
and breaks organic complexes to create free metal ions which are
more readily removed.
Preozonation of effluent was demonstrated to extend
activated carbon life and improve removal (Paper No. 33, U.S.A.).
Similar results were reported by South African and Swiss workers.
pH was shown to be a critical parameter affecting the
rate at which aromatic compounds are oxidized in the ozonation
processes. Ozonation of naturally-occurring and anthropogenic com-
pounds were both shown to be enhanced with elevated pH values
(Paper No. 28, Federal Republic of Germany).
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The magnetite process can theoretically allow the
clarification process to proceed at a much faster rate but may
not produce acceptable color and turbidity in the final
effluent (Poster Presentation S37, Australia).
Fixed Film Biological Reactors
Modeling of fixed film biological reactors received
appreciable attention (for example, Paper No. 59, France; and
Paper No. 61, Japan and Thailand). Participants were critical,
however, of oversimplifications contained in the models.
Effects of turbulence and other factors controlling
transfer of oxygen to the bulk liquid of rotating biological
contactors (RBC) were shown to become relatively less significant
as the size of RBC units increases (Paper No. 27, U.S.A.). Most
oxygen transfer occurs through the biofilm.
The resistance to outward diffusion of bicarbonate and
carbonate ions was shown to cause elevation of pH in biofilms
used for denitrification (Paper No. 63, Denmark).
Results from a study on mass transport within biofilms
(Paper No. 25, Japan) contradicted earlier results and necessi-
tates additional research.
Nitrifying organisms in fixed film reactors were found
to be generally less sensitive to inhibition than those in sus-
pended growth reactors (Paper No. 57, France).
A mathematical model for predicting the performance of
aerated activated carbon biofiIters was presented (Paper No. 31,
France). At low organic loadings, continuous biological regenera-
tion occurs, but at high loadings biological growth hinders
adsorption and leads to clogging.
Installation of rotating biological contactors in modified
primary settling tanks was described (Paper No. 5, U.S.A.).
Suspended Growth Biological Reactors
Use of the Marais-Ekama model to predict performance of
full-scale activated sludge plants was reported (Paper No. 29,
South Africa). Reasonable predictions of COD, TKN, ammonia and
nitrate concentrations were considered to be obtained.
Two very similar systems for nitrogen removal by bio-
logical nitrification and denitrification in a single-sludge system
were reported. The treatment processes were developed independently
in South Africa (Paper No. 8) and in Japan (see discussion of Paper
No. 8).
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Control of bulking in the activated sludge process may
be achieved by control of process configuration (Paper No. 2,
U.S.A.). Use of an initial "selector" containing 1/74 of the
aeration tank volume was successful. Causative mechanisms are
not yet understood, but removal of dissolved substrate in the
selector seems to be important. There seemed to be general agree-
ment among conference participants that basin configuration plays
an important role in control of filamentous bulking.
A two-stage high-rate algal wastewater treatment system
was shown to remove wastewater nitrogen to a level of 4 mgH
and phosphorous to less than 0.5 mg/1. This use of micro-algae
for nutrient extraction was also shown to effectively remove
other growth factors which stimulate algal growth in the natural
environment (Paper No. 20, Israel).
Anaerobic fermentation was shown to be effective means
of treating potato-processing wastewaters (Paper No. 41, Australia).
Work in South Africa (Poster Presentations S17, S18,
and S33, South Africa) has developed a rational basis for design
and operation of activated sludge plants for phosphorus removal
without chemical addition. kcAyioAoba.cX.2A was established as the
primary biological agent. Research established that totally-
anaerobic conditions must precede aerobic tanks for the excess
phosphorus removal to occur. This combination is not accomplished
in the typical Bardenpho-Phoredox type plants. Their work indi-
cated that AcUn&tobacAeA gained a growth advantage when anaerobic
conditions are present. Chemical removal of phosphorus in bio-
films was investigated in a laboratory study (Poster Presentation
S32, Denmark).
Sludge Treatment, Utilization, and Disposal
Clinker formation in multiple hearth furnaces was found
to be associated with high temperatures and long residence times.
Volatilization of cadmium from sludge incinerated in a multiple
hearth furnace was reported to be increased at higher temperaturesj
but most of the cadmium was recovered in scrubber water (Paper
No. 11, Canada).
The potential use of rheological measures to identify
optimal sludge conditioning dosages was described (Paper No. 14,
Canada).
Pasteurization of sludge using submerged combustion of
digester gas before anaerobic digestion was reported (Paper No.
51, Federal Republic of Germany). New German regulations will
require pasteurization or equivalent treatment of sludge applied
to pastures beginning in 1986.
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Because of high capital costs and low efficiency of
energy recovery, anaerobic digestion was considered to be
inferior to thermophilic aerobic digestion at small installa-
tions (Paper No. 49, Federal Republic of Germany).
Wall growths were found to have appreciable influence
on the performance of laboratory-scale anaerobic digesters
(Paper No. 53, Portugal and United Kingdom). In inhibition
studies, it was found that removal of wall growths caused failure
conditions to be reached more readily.
Recycle of magnesium from sludge produced by precipi-
tation of phosphorus with lime was reported (Paper No. 39, Israel).
The magnesium serves as a flocculant and lime dosage is reduced.
An attempt was made to identify design and operational
practices that lead to integrated systems of sludge management
with low cost (Paper No. 55, U.S.A.). Short mean cell residence
time in the activated sludge process, large thickeners, and
ocean disposal favor cost reduction. The mode of sludge trans-
portation used has a very significant effect on costs.
The role of cationic polyelectrolytes in flotation
thickening of conditioned activated sludge was presented. Mole-
cular weight and ionic charge were indicated to be significant
variables (Paper No. 43, Canada).
Metal phosphating and pickling sludges were extracted
using distilled water in a lysimeter to determine long-term effects
of leaching from a segregated landfill (Paper No. 47, U.S.A.).
Current South African regulations for land spreading of
sludges are based on the philosophy that only a sludge with no
E. Coti, AtccuuA ova or pathogenic viruses is one unlikely to
cause disease (Poster Presentation S6, South Africa). Current
research in South Africa is directed to developing data on safe
levels of these agents, as well as for metals, for spreading or
land use for various purposes. Aaccvua ova were found to be resis-
tant to inactivation by major sludge treatment methods (Poster
Presentation S36).
Wastewater Reclamation
Operational performance of wastewater reclamation plants
at Stander and Pretoria, South Africa and Windhoek, Namibia was
reviewed (Paper No. 3, South Africa). Experience at the Windhoek
plant, in particular, had proved the practical feasibility and
safety of direct reclamation of wastewater for potable uses. For
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example, using a hamster cell transformation assay, reclaimed
water from the Windhoek plant was shown to have a quality similar
to that of an excellent drinking water, as far as content of po-
tential carcinogens and toxicants (Paper No. 6, South Africa).
In addition, using extensive chemical analysis of volatile halogenated
hydrocarbons, chlorinated hydrocarbons and pesticides, chlorophenols,
PAH, and phenolic compounds, the finished chlorinated water of the
direct reuse system at Windhoek was judged to be of high quality
and better than that of an indirect reuse system using water from
a surface water source (Paper No. 9, South Africa).
Treatment requirements for use in recycling wastewater
are dictated by the intended use of the wastewater, institutional
considerations and 1 imitations, economic issues, and health con-
siderations and quality criteria. Use of aquifers for storage
for reclaimed wastewaters does not eliminate monitoring problems
since, if a deleterious substance is discovered prior to distribu-
tion, a public health problem is eliminated but a useful aquifer
is contaminated (Workshop-Theme 6).
The use of water recycling techniques by numerous indus-
tries in Germany was presented. The consensus of South African
opinion regarding potable reuse of wastewater was that indirect
and unplanned reuse of water containing effluents and planned
recycling of reclaimed wastewater for potable purposes were
essentially identical. Implementation of new standards for direct
reclaimed wastewater were not considered to be necessary (Workshop-
Theme 6). Although there is considerable concern in many countries
regarding the need for additional research on characterization of
reclaimed wastewaters prior to potable reuse, countries where
water resources have become limited have taken the position that
some risks associated with reuse of reclaimed wastewater must be
taken and that all issues regarding potable water quality need
not be known.
Issues regarding mineralization of surface water supplies
due to continuous dewatering of goldmines, dissolution of salts
from mine rocks and sand dumps and sewage or industrial wastes was
discussed in detail. Examples of types of costs and impacts con-
sidered and treatment systems to be used to prevent mineralization
were presented (Paper No. 12, South Africa).
Monitoring Systems and Strategies
Use of fish for continuous biological monitoring was
advocated (Paper No. 32, South Africa), and it was indicated that
10% of the lethal level could ordinarily be detected.
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A long-term survey, conducted in the surf waters
near Durban, South Africa, was used to indicate improvements
in bacteriological quality of surf waters over a ten-year
study period resulting from improvements in wastewater treatment
systems (Paper No. 1, South Africa).
Sharks were shown to be excellent indicator organisms
for monitoring heavy metal pollution, especially copper, lead,
zinc and mercury. Initial data indicate that sharks may also be
excellent organisms for use in monitoring for such organic com-
pounds as PCBj DDE, DDT, dieldrin and camphloclor (Paper No. 7,
South Africa).
A comprehensive predischarge base-line study in conjunc-
tion with long-term postdischarge surveillance program for a nickel
refinery was presented. It was concluded that since species
diversity may vary seasonally as a result of species interactions,
climatic variations and spacial heterogeneity, extensive predischarge
studies must be conducted in conjunction with long-term postdis-
charge monitoring. The natural cycles of species making up a popu-
lation must be considered when conducting environmental monitoring
programs (Paper No. 10, Australia).
High toxicity of polyelectrolytes to fish was demonstrated
in a study originally designed to test a dynamic testing apparatus
(Poster Presentation S14, Canada). These chemicals, used in waste-
water treatment, may be potentially hazardous to aquatic life in
receiving waters.
Microbial Resistance of Indicator Organisms
The ability of microorganisms to adapt to unfavorable
environment conditions and the selection of resistance of microbial
strains were discussed in detail. Data indicating the mutation of
E. Coti type II to CItAobauteA fawndii types I and II were
presented and questioned by conference participants. Considerable
discussions were focused on factors associated with adaptation of
a microorganism as opposed to the production of genetically-stable
mutations in an unfavorable environment (Paper No. 24, Japan).
With regard to resistance of indicator microorganisms
to combined chlorine, E. Coti was a predominant organism isolated
from unchlorinated sewage treatment processes and ranked fifth of
twelve genera in resistance to combined chlorine. E. Coti, however,
was not found in chlorinated tertiary effluents and EntoAobacteA
species were the most dominant organisms. Issues regarding mechanism
and extent of chlorine resistance were discussed in detail. Con-
siderable concern was noted over the potential for development of
chlorine-resistant microbes, both indicator microorganisms and
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pathogenic microorganisms. The question of the need for chlorina-
tion of wastewater effluents was seriously questioned (Paper No. 26,
U.S.A.).
Mutagenic Activity
Water samples were analyzed directly following filtration
(0.22 um membrane filter) with hamster cells to monitor for potential
carcinogens and toxicants using transformation assays. Transforma-
tion and survival were determined by counting colonies after an
eight-day incubation period using benzo-a-pyrene as a positive
control (Paper No. 6, South Africa).
Mutagenic activity, as determined by the Ames test, was
consistently found in concentrated samples from 14 of 19 sampling
points in Pretoria's drinking water sources (Paper No. 34, South Africa).
Virus Inactivation and Removal
Model enteroviruses were shown to be removed during
filtration in conjunction with fine turbidity particles, indicating
adsorption to turbidity particles was responsible for a major
portion of virus removal. In addition, alum addition enhanced
adsorption of viruses to coagulant particles and their subsequent
removal (Paper No. 48, India).
Enteroviruses were effectively removed with an automated
hollow-fiber ultrafiltration system using polysulfone membranes
(pore opening of 250 ym). Membrane-adsorbed viruses were not
recovered using permeate alone for backwashing but were successfully
removed using pH buffers and glycine (Paper No. 50, U.S.A.).
Adsorption of enteroviruses from sewage was successfully achieved
by adsorption onto preformed aluminum hydroxide floes (Paper No. 52,
Brazil). Enteroviruses were successfully recovered from drinking
water and river water samples at recoveries of 30% to 41% using glass
powder with diameters of 100 to 200 ym (Paper No. 54, France).
Regrowth of bacteria in ozonated drinking waters was
attributed to production of aldyhydes and ketones during the
ozonation process. Addition of chlorine with ozone retarded,
but did not eliminate the regrowth. Ozonation, furthermore, was
shown to markedly reduce the potential for generation of trihalo-
methanes on subsequent chlorination of drinking waters (Paper No. 56,
Switzerland).
Ozone was shown to effectively destroy the structural
integrity of bacteriophage T4 at doses of 0.2 - 0.5 mgA in two
minutes or less. Electron microscopy data indicated that rapid
fragmentation of released DNA occurred within this time period
(Paper No. 58, U.S.A.).
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Eutrophication
A Water Quality Index was used to indicate improvements
in water quality in an urban reservoir resulting from the termina-
tion of nutrient flow from an influent wastewater treatment plant
(Paper No. 60, Federal Republic of Germany).
A two-year study of an urban catchment was conducted to
determine the means of import and export of nitrogen, phosphorus,
COD, BOD, and heavy metals. Atmospheric deposition accounted for
virtually all of the soluble nitrogen contained in storm water
transport but accounted for less than half of the other materials
in runoff. The use of the unmodified SWMM model produced excellent
runoff hydrographs but failed to predict the transport of pollutants
in storm water. This lack of correlation was attributed to the lack
of appropriate atmospheric deposition rates in the model (Paper No.
62, South Africa).
The treatment of the total flow of an influent river to
a major reservoir in Bonn, Germany using chemical precipitation,
flocculation and filtration was successful in reducing total phos-
phorous content from 100-150 yg/£ to approximately 5 yg/ji
(Paper No. 15, Federal Republic of Germany). Treatment of the total
river influent to the reservoir reduced reservoir phosphorous
concentrations from approximately 25 yg/2 in 1970 to 11 ug/ji in
1980. Considerable reductions in reservoir biomass, chlorophyll-a
and transparency of the reservoir were achieved.
Algal growths in the Ruhr River occur to the extent that
stream aeration is required and water treatment plant capacity is
affected. Phosphorus is the limiting nutrient and a source con-
trol program has been implemented (Paper No. 38, Federal Republic
of Germany).
Raw Mater Quality
Studies conducted to determine causes of taste and odor
in natural river waters must include comprehensive monitoring
of inorganic and organic constituents as well as detailed evaluations
of resident algal populations (Paper No. 13, France).
The concentration of nitrates in the Thames River increased
from an average value of 4.2 mg N/£ in 1968 to 7.7 mg N/i. in
1979, and based on model projections, it will be 9.8 to 15.5 mg N/£
by the year 2000. A new European Economic Community Directive
establishes a maximum permissible nitrate concentration of 11.3 mg
N/£ (Paper No. 46, United Kingdom).
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Oil
The Federal Republic of Germany subsidizes collection
of lubricating oils. In France, prices paid for waste oils are
controlled and disposers are licensed (Workshop-Theme 2).
The convener of a State-of-the-Art Workshop on Oil
Pollution in Marine and Fresh Water Environments concluded that
(1) existing international agreements must be made more effective;
(2) sources of oil pollution cannot be considered apart from
effects; (3) adverse local effects must not be underestimated;
(4) the question of whether a few supertankers are more desirable
than a larger number of small tankers remains unresolved; and
(5) available oil pollution abatement technology is improving
(Workshop-Theme 2).
Sediments
Use of a rotating annular channel to measure the deposi-
tional properties of silts in bays and estuaries was described
(Paper No. 36, Japan).
It was reported that the potential for phosphorus release
from sediments is indicated by the amount of phosphorus released
by extraction with sodium hydroxide (Paper No. 42, Japan). This
phosphorus existed as iron or aluminum phosphate or it was
adsorbed.
Large quantities of phosphorus can be stored in oxygenated
surficial sediments and subsequently released during anaerobic
conditions (Paper No. 44, U.S.A.). The primary mechanism is
anaerobic destruction of insoluble ferric iron compounds with release
of sorbed and precipitated phosphorous species.
Mathemati cal Modeli ng
The state-of-the-art workshop identified pitfalls in
mathematical modeling in monitoring water pollution as including
poor communication between modelers and decision makers, use of
sophisticated models for the solution of simplistic problems, and
lack of adequate model verification (Workshop-Theme 1).
Technology Transfer
Major needs in the area of technology transfer were identi-
fied (Workshop-Theme 4). Improved communication between researchers,
consultants, equipment manufacturers and operating personnel was
identified as a major requirement for successful improvement in
transfer of new and developing technologies.
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The scaling of reactor systems from laboratory and
pilot-scale systems to full-scale wastewater treatment systems
was indicated as a major research need in the area to technology
transfer (Workshop-Theme 4).
Nuclear Power Plants
A study of the significance of a nuclear power reactor
on water quality in rivers subject to low flows was reported
(Paper No. 40, Belgium). Reduction in flow, thermal impact,
discharge of radioactive material, and enrichment in salts and
suspended matter were considered.
Developing Countries
The state-of-the-art workshop on water pollution control
in developing areas emphasized appropriate regulations, training,
and appropriate technology (Workshop-Theme 5).
Pollution Control Funding
The same problems of funding for pollution control
activities exist throughout the world. Reasons for the difficulty
in attaining funding must be established in order to achieve
progress in water pollution control (Workshop-Theme 3).
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DEVELOPMENTS OUTSIDE OF FORMAL SESSIONS
Much of the beneficial exchange of technical information
occurring at professional meetings takes place outside of the
formal sessions. At international conferences, the opportunities
for such effective information transfer are considerable. Recog-
nizing this potential, participants in the development of this
report were asked to submit comments obtained from such inter-
actions with water pollution researchers from other nations. Com-
ments of possible interest to U.S. water pollution researchers, not
part of the formal conference program, are summarized in this section.
These comments have been identified with an individual participant
and do not necessarily reflect the views of USANC.
Coal Gasification Wastewater Treatment
Several observations and comments relating to this topic
were presented in the main body of the report and are not repeated
here relating to water pollution control at South Africa's SASOL II
coal gasification plant near Secunda. SASOL is the acronym for the
South African Coal, Oil and Gas Corporation. It represents the
largest synfuels operation in the world and is presently meeting
close to 20% of the petroleum demands of the country (Heaton).
SASOL I, located at Sasolburg and southwest of
Johannesburg, has been converting coal to gaseous and liquid
products since 1957. SASOL II was completed in 1980 at a cost
of approximately $2.5 billion and is near Secunda, which is east
of Johannesburg. SASOL III, a mirror image of SASOL II, began
operation this year at the same site and was built at a cost of
$3.5 bill ion.
Little detailed information is available, such as
output, actual costs and government subsidies because of national
security issues. However, the following information was made
available on the scheduled tour (Wednesday, April 7, 1982) to
SASOL II:
(1) Gasoline at service stations sells for 66<£/£
and SASOL technology is competitive at this price. When the
plants were built, it was not and the management depended
heavily on inflation and increases in world oil prices to
justify construction. Their attitude toward our United States
synfuels industry is that, "If we don't do it now, we'll never
do it." However, South Africa is in a unique position in that
they have no natural oil and few friendly nations with which to
trade.
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(2) Coal is one answer to their energy situation and
several hundred years of good anthracite supplies are available
as in the United States.
(3) Much has already been done to establish a South
African framework to promote the synfuels industry. It has govern-
ment assurance (adhering to their 40-year-old principle) that
prices of indigenous products will be allowed to follow international
oil prices.
(4) Effective synfuel projects require huge capital
investments and a long period between investment and income stages.
It was their conclusion that this was still the major obstacle to
worldwide alternative fuel projects. It is generally accepted in
their country that the synfuel industry requires more government
involvement than mere rate protection.
(5) In the South African context, it is necessary for
government to assume the role of temporary entrepreneur in partner-
ship with private investors as was the case of SASOL II and III.
The relative scale of participation would depend on requirements
of the investors involved. The government, in due course, will
earn a realistic return on its investment in the forms of interest,
dividends and capital gains. Original investments in SASOL I, which
commenced in the 1950's, not only earned dividends but were repaid
sevenfold in 1979.
(6) SASOL IV will probably not be considered until the
1990's. Manpower and training are more critical problems than
initial financing and technology. SASOL II and III were the
biggest industrial projects on one site ever undertaken in the world.
(7) SASOL II alone will mine 27.5 million tons of nearby
coal annually with a 70-year useful life; 40,000 ton/d are consumed
in the process to produce approximately 55,000 barrels of fuel.
(8) The basic overall procedure of the coal gasification/
1iquification process is to combine crushed coal with steam and pure
oxygen to form raw gas for upgrading into petroleum and other chemical
products. Computerized control is used throughout. Thirteen
thousand (13,000) tons per day of O2 are produced at SASOL II, the
largest plant in the world.
(9) Very important to the overall economics of the system
is by-product recovery and marketing of sulfur, phenols, ammonia,
alcohols, ketones, ethylenes, LPG, waxes, tar products, and solvents.
Several industries have developed around SASOL to produce materials
from these feedstocks, e.g., plastics, fertilizers, and explosives.
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(10) In comparison with United States oil-shale pro-
cessing, the SASOL system is perhaps 50% more complicated and
technically difficult with concomitant increases in cost.
(11) The plant was constructed 58 km from the nearest
water source and 160 km from the nearest feasible wastewater
discharge point. Thus, a zero-discharge situation was mandated
from the beginning. A dam was built on the upper Vaal River
and water was piped to the complex. Eventually, 95 x 10^ m^/d
of water will be withdrawn and consumed at SASOL II and III.
Seventy percent of the water is used" for cooling purposes and
the remainder is used to produce steam as follows: 10% for
gasification; 10% for electrical generation; and 10% for general
purposes and heating. Insufficient electricity is generated on-
site and power is purchased from nearby coal-fired plants.
(12) Two separate water systems are employed in the
plant: (a) raw water/utility cooling/boiler feed water treat-
ment; and,(b) wastewater upgrading and process cooling. In the
first system,(a), raw water is brought to SASOL via gravity flow
from the dam. Clarification occurs in settling basins and the
water used directly in hyperbolic utility cooling towers which
serve the steam and oxygen plants. Two or less concentration
cycles are used, then the water is taken to the boiler-water
preparation facility. Three qualities of water are produced for
various boiler feeds from the following treatment steps: hot-
lime softening and sodium ion exchange for steam plant boilers;
hot-lime softening and demineralization plant for waste heat
boilers; and hot-lime softening, demineralization and ion-exchange
polishing for high pressure waste heat boilers. Careful control
is maintained to eliminate any oily wastes from this water loop.
The second or effluent upgrading system,(b),is entirely
distinct and separate from previous processes. All wastewaters,
process effluents, storm waters, oily sewers and domestic sewage
are collected and treated by the activated sludge process. Cal-
cium flouride was previously precipitated with lime but has been
discontinued. The biological process is used to nitrify and
denitrify in several stages but has not been achieved because of
the highly variable nature of the feeds. Solids are centrifuged
and incinerated onsite. The biologically-treated (BI0X) effluent
is filtered and subjected to activated carbon adsorption for COD
removal, then treated by ion exchange for soluble salt reduction.
Carbon regeneration is accomplished onsite. Treated water is
consumed in two hyperbolic process cooling towers after four cycles
of concentration. Brines are taken to a thermal concentrator and
disposed of in abandoned coal mines or the ash piles.
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(13) The ultimate disposal of waste products will be
in coal-ash piles. Literally, mountains of the material will
be created around the flatlands of SASOL II and II and contain
brines and all hazardous wastes. Eventually, the piles will
be revegetated with seepage water recycled.
(14) Corrosion became a severe problem in the second
water loop (i.e., 12(b)) and cooling tower life was reduced to
one-two years. The only solution, thus far, has been to use
chromate inhibitors. Careful monitoring of the biological
system (BIOX) is taking place to note the effects of chromate
poisoning on biological growths.
(15) Two important factors come from the SASOL technical
tour as related to water balances and treatment at Colony. Their
BIOX system does not operate as designed or meet their expectations.
This was a result of inadequate or practically non-existent pilot
work because of time constraints in development. In start-up
operations, tremendous quantities of water were created before
equilibrium could be achieved. It is important to have adequate
storage for these waters which will then be returned to the evapora-
tive system over a long period of time (Heaton).
Pollution control technology in the United States synfuels
industry is a new field. Zero discharge mandates extensive treat-
ment and recycl ing technology and the waste products are unique.
Increased research by private concerns, DOE and EPA is necessary
to allow closed-loop operations and evaluate the delicate balance
between environmental regulations and national energy needs (Heaton).
The SASOL I facility treats synthetic fuels wastewater
in conjunction with municipal wastes in a system incorporating
biological filtration and disposal via a slimes pond. Regulations
for the SASOL II and SASOL III complexes are different than that
for the SASOL I complex (Neufeld).
Research is underway at SASOL to examine questions of
water reuse via advanced waste treatment technologies paralleling
that being conducted at major universities in the United States.
The SASOL complex, however, is capable of using larger pilot
facilities than those in the United States since limitations of
wastewater availability, as experienced by American universities
and DOE, do not exist in South Africa. A need exists to develop
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better criteria for reuse water quality, and for linkages of
processes for treatment. Disposal via evaporative cooling
is being considered. Since South Africa is a dry climate,
disposal of cooling tower blowdowns on land is a viable approach
which may not be applicable in the United States (Neufeld).
Biological Wastewater Treatment
The use of fixed film systems, particularly RBCs, are
becoming widespread throughout Europe and Africa. Many RBC plants
in South Africa are greatly simplified as compared to those being
built in the United States. Most of them are being constructed
to provide nitrification as well as for organic removal (Bishop).
Biological fluidized bed treatment systems are receiving
much attention in the United Kingdom and several experimental full-
scale systems are in operation (Bishop).
The impact of high energy costs has led engineers and
operators to look to more efficient aeration systems. The Water
Research Centre at Stevenage, United Kingdom, is currently per-
forming demonstration studies at Rye Meads to demonstrate the
low use of energy, consistent quality of effluent and reliability,
flexibility, and cost-effectiveness of using fine-bubble diffused
aeration (Boyle).
Ebera-Infilco (Ebera-Infilco Research Center, Fujisawa 47-20,
Fujisawa-shi 251, Japan), M. Kitagawa, K. Watanabe, and M. Kobayashi
have developed and tested, on a pulp and paper waste, a new modifi-
cation of the activated sludge process termed "Bulking Free Process"
(BFP). In the process the recycle activated sludge (RAS) stream is
split; a small fraction (approximately 5-10%) is conveyed to a
small initial aeration basin where it mixes with influent wastewater.
The bulk of the RAS is fed to a larger aeration basin that receives
the effluent from the small initial aeration basin. The organic
loading on the initial aeration basin should be >5 kg BOD/kg
MLSS-day (Jenkins).
The Water Research Centre in Stevenage, United Kingdom,
is in the process of conducting a demonstration study on the use
of the Simon-Hartley Captor process. The Captor process employs
2.5 cm by 2.5 cm by 1.25 cm plastic porous pieces in an aeration
tank. This "fixed" suspension growth system is capable of con-
centrating biomass in a small reactor volume. The project will
be reviewing the efficacy of this process in the carbonaceous
stage of a two-stage nitrification system (Boyle).
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Commercial sector activity is increasing in the area
of developing fluidized bed, expanded bed, and fixed film/suspended
film hybrid systems for the biological treatment of carbonaceous
and nitrogenous materials. Commercial scale systems, applied in
France, have been piloted on an "in/out" basis with relatively
low levels of fundamental modeling support. Many have agreed
that a need exists to develop and apply theoretical models of
such hybrid systems to pilot-scaled facilities for confirmation
and calibration (Neufeld).
Eutrophication
Interest in eutrophication continues to be widespread
throughout the world. In particular, the impact of eutrophication
on the quality of raw water sources for municipal supplies is
receiving increasing attention. The importance of making careful
nutrient budgets to give full consideration to internal as well as
external sources of nutrients is more widely recognized. The need
for a better understanding of the extent of internal sources
is justified, because as external sources are brought under
control, internal sources may have a major influence on eutrophi-
cation. As phosphorus becomes more widely controlled, the control
of nitrogen is receiving increasing attention (Rohlich).
Phosphorus Removal
Interest continues over the most cost-effective methodology
for removing nutrients from wastewater. Research emphasis has
shifted from physical-chemical to biological methodology. Signifi-
cant discussion occurred and some controversy developed while dealing
with mechanisms and optimal design for biological nitrogen and
phosphorus removal (Englande).
There are 30 existing plants in South Africa in which phosphorous
removal is practiced. Of these, 15 are of the multi-stage activated-
sludge Bardenpho type. A survey of 11 of these plants showed that
only one was meeting secondary effluent levels of 1 mg P/I. The
major problem appeared to be in lack of anaerobic conditions in
the anaerobic basin due either to the presence of nitrates
(i.e., COD/TKN ratio is too low) or DO (aeration of RAS and waste
streams by screw pumps or in channels). Low COD/TKN ratios were
often produced by primary sedimentation that removed proportionately
more COD than TKN. Suggested remedies involve bypass of primary
sedimentation and addition of acid-fermented primary sludge
(Jenkins).
A visit to the Bardenpho plant at Goudkoppies, Johannesburg,
revealed: (1) Significant activated sludge settling problems
(SVI 200-300 m£/g) likely due to anaerobic and anoxic basins in the
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treatment system; (2) significant Uocandia. foaming; (3) the COD/TKN
ratio of the waste had been increased by diverting to the plant a
high-COD yeast waste; (4) there was considerable short circuiting
of the anaerobic basin and back mixing of aerobic and anoxic basins
due to aerator placement; (5) the effluent quality after the first
aerobic basin was the same as that following the second aerobic
basin. It is concluded that, in this case, the second pair of
anoxic/aerobic basins were not needed; (6) the plant is run with
manual control because it was found to be impossible to run it on
automatic control using DO sensors (Jenkins).
A post-conference seminar in Pretoria on Biological
Phophorus Removal reached the following conclusions on generally
accepted knowledge concerning enhanced P removal in biological
waste treatment systems. With respect to biological mechanisms:
(1) enhanced P removal is due to polyphosphate accumulation in
bacteria or chemical precipitation or both; (2) enhanced P removal
via polyphosphate accumulation requires that the activated sludge
has been through an anaerobic fermentation stage; (3) the anaerobic
fermentaton unit processes organic matter either directly from the
sewage or from the activated sludge itself; (4) for plants incor-
porating nitrogen removal the following must hold for successful
biological P removal: COD/TKN ratio > 10; (5) there was agreement
that the cations K+ and Mg2+ accompanied the biological uptake and
release of P (Jenkins, Randall).
With respect to chemical mechanisms, the following con-
clusions were established: (1) chemical precipitation is promoted
by relatively high concentrations of P, and cations of [Ca^+, Fe(II);
Fe(III), Zn2 ] and an alkaline pH; (2) phosphorus precipitation is
inhibited by ions such as P207^", Mg2+, CO32-, phosphates, and
polyvalent carboxylic acids; (3) microorganisms modify wastewater
quality with respect to P concentration, cations, pH and they
influence P precipitation; (4) P precipitates are amorphous, poorly-
crystalline and complex when in biological systems (Jenkins).
A proposal for the formation of an international study
group was prepared for submission to IAWPRC on the subject of
Biological P Removal. The chairman is D. Jenkins, Berkeley, U.S.A.;
the secretary is H. N. S. Weichers, Pretoria, South Africa. The study
group plans to operate by correspondence and to meet just prior to
the 12th IAWPRC Conference (Jenkins).
An innovative design of secondary clarifiers has been
used at the Cape Flats sewage treatment plant, located near Cape
Town. The flow is from the perimeter but enters through conduits
that extend a substantial distance towards the center of the
clarifier in an attempt to avoid short-circuiting over the weir,
which is also located around the perimeter. Settled sludge is
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removed by a rotating suction device. In spite of these changes,
the operators stated that the effluent quality was not noticeably
better than that obtained with center feed, rim-overflow clari-
fiers. The Cape Flats plant is a biological nutrient removal
facility, however, and its sludge may be more difficult to settle
than that of a conventional plant (Randall).
M. R. Roberts and D. A. Kerdachi (South Africa) have
accumulated extensive experience with a unique full-scale
phosphorus removal plant located at Pinetown Municipality in the
Natal, South Africa. This plant has a single aeration tank and is
in a soft-water region, yet it has consistently achieved effluent
phosphorus concentrations of less than 1 mg/I, corresponding to
removals of 92% or more without chemical addition. The high removals
were originally observed when the plant was operating at a sludge
age of 20 days with total anaerobiosis periods of 10 to 12 hours each
day. However, they have also demonstrated high phosphorus removals
at sludge ages of 38 and 69 days. The success of the process was
attributed to the functioning of two mechanisms which complement
one another, chemical removal and excess biological uptake. Under
the 20-d sludge age conditions, high phosphate release and excess
biological uptake were achieved, but this was gradually shifted to
where the primary phosphorus removal mechanics were governed by
the equilibrium kinetics of a solid phosphate phase by increasing
the sludge age. The process would seem to have a considerable
economic advantage over the multiple unit design of the
Bardenpho/Phoredox processes, and could be readily adapted to
existing conventional plants (Randall).
The combined effects of excess biological phosphorus
removal and biologically-mediated phosphorus removal have been
studied by E. Arvin of the Technical University of Denmark
using a unique system. This system has three or four aeration
tanks which are operated in sequence on a batch basis. While one
is filling under anaerobic conditions, a second is being aerated
and, in a third, the previously aerated sludge is being settled.
The fourth can be emptying while the first is filling. Excellent
phosphorus removal results have been obtained with this system
and Arvin (Department of Sanitary Engineering, Technical University
of Denmark, Building 115, DK-2800 Lyngby, DENMARK) has written
papers describing the conditions needed to maximize biologically
mediated phosphorus precipitation (Randall).
Sludge Treatment and Disposal
An informal discussion with engineers from Japan revealed
that sludge treatment and disposal are receiving a great deal of
attention because of land shortage and high cost of treatment. In
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Tokyo, incineration is the preferred method of disposal. Electro-
static precipitators are employed to prevent air pollution. Com-
posting of sludge and utilization of ash after incineration are
also being studied (Kawata).
Quality of Treatment Plant Operation and Performance
Operation and maintenance of sewage treatment plants
outside of large municipalities in South Africa is a significant
problem. Lack of knowledge of sewage treatment principles is a
critical problem. The Institute of Water Pollution Control (South
African Branch) offers training courses. Simple plants need to be
built, e.g., for the semi-autonomous states such as the T.ranskei;
trickling filters are being designed rather than activated sludge
on the logic that a non-operative trickling filter will produce
a better effluent than a poorly operated activated sludge plant
(Jenkins).
Wastewater Reclamation
The South Africans have been leaders in the development
of water reclamation methodology. A very interesting state-of-the-
art presentation was given which summarized these efforts. Un-
fortunately, little in the way of new technology was presented.
However, several changes discussed included the trend toward use of
biological methodology for removal of nitrogen and phosphorus. At
the Windhoek facility, it was noted that the ammonia stripping
towers were presently not used (Englande).
The National Institute for Water Research in Pretoria,
South Africa, is involved in ambitious studies to improve the
conversion of treated municipal sewage into drinking water (Keith).
There is little doubt of the need to develop new water
sources in arid sections in the United States. Two main philosophies
are being followed. In one, uses of wastewater are directed toward
low human contact such as irrigation and ground water recharge
either through direct injection or percolation. The other envisions
full treatment of wastewater to meet drinking water quality standards
and its integration into potable supplies (Olson).
The most cost-effective means of increasing water resources
at this time appears to be through the use of treated wastewater for
irrigation purposes. This procedure has several advantages over those
of direct reuse. The margin of safety is not so critical. The major
causes of waterborne disease in the United States today are failures
in treatment plant operations, principally in failures in disinfec-
tion. Delegates from different countries have different ideas on which
strategy to follow. In Israel the decision has been made to restrict
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reuse to irrigation. This is based on public health considerations
and treatment costs. In South Africa, the main thrust is for direct
reuse. In the United States various states, have adopted different
strategies. In Colorado, the decision for direct reuse for the city
of Denver has been made, while California has decided on low contact
uses of reclaimed water throughout the state (Olson).
Water reuse is still receiving attention despite the
increasing energy cost related to physical-chemical treatment
processes. However, a gradual shift has been noted away from
adsorption processes such as activated carbon toward ground-
water recharge. The latter process allows greater detention
times (e.g., months instead of minutes) and greater bed depth and
travel distances (e.g., hundreds of meters instead of meters).
Although the adsorption capacity is not as great as compared to
activated carbon, the longer travel distance compensates for it.
When a monitoring well is installed between the recharge well and
the pumped well, a regular monitoring program will give timely
warning of possible toxic sludges migrating towards the pumped well.
Groundwater recharge can be an alternative for the more expensive
activated carbon adsorption and should, therefore, be studied in greater
detail (DeWalle).
Due to a shortage of water in South Africa, much the same
as in t!ie arid southwestern region of the United States, a respectable
level of research and engineering activities has been conducted in
South Africa. The most impressive studies concern the total reuse
of wastewater generated from SASOL II and III synthetic fuel plants
and the potable reuse of municipal wastewater effluents. It was
observed during the field trips that intensive efforts were made to
monitor for both toxic substances and biological parameters, including
viruses, to insure the safety of water reuse and the sound disposal
of resulting sludges. Although comparable water renovation studies
have been conducted in the United States, the level of activity is
far from intense. This is especially true if one compares the
effective manpower available in South Africa to that in the United
States (approximately 1:50). The South Africans have demonstrated
innovative use of research results from the United States. An
intensive effort in technology transfer is evidenced by the large-
scale applications of activated carbon and ion-exchange resins in
South African water renovation projects, including the use of carbon
and resin regeneration processes. In view of the potential long-
term water shortage in many parts of the United States, it is im-
perative that further long-term research be supported by EPA to fully
expand our knowledge in areas of water reuse (Chian)-
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Ocean Discharge
Even with the great emphasis in water reuse, South Africa
is studying and planning ocean discharge of wastewater following
minimal treatment (Kawata).
Animal Feed from Algae
The National Institute for Water Research in Pretoria
has improved the conversion of algae to animal feeds by advanced
technology which shortens the time of processing it and also uses
less energy to dry the product (Keith).
Pathogenic Organisms and Viruses
Antibiotic-resistant cholera is becoming endemic through-
out most of Africa, and cholera is now being found in waters where
it had not been previously, including in South Africa (Bishop).
Parasite viability in sludges following land spreading
was of general interest since these organisms are generally more
resistant to deactivation than bacteria and viruses. A follow-up
session on sludge handling at the post-conference workshop dealt
with the problem in more detail. While in England, parasites are
not considered a problem in sludges, other countries such as Germany,
South Africa and Switzerland are considering limiting the levels
of specific parasites in the sludge if it is to be disposed on land
for agricultrual purposes (Englande).
The study group on water virology formed by IAWPRC
arranged a post-conference seminar on water virology. Various
aspects of water virology research needs and priorities were
discussed (Roy).
The reappearance of Vibtiio choleAae. along the Southern
Coast of the United States is an issue which should be of prominent
concern. The origin of these organisms, as those appearing in sea
water along the Natal coast South Africa, appear to be from non-
point source discharges. I/. choleAaz in many instances appears to
be multiplying in fresh water environments and then transported into
the marine environment where they are concentrated in shellfish
and present a potential health threat. Other new disease agents
are also appearing and the origin appears in certain instances
to be environmental, ye-tam-ai as well as
CampylobacXeJi are accounting for higher incidence of waterborne
disease and are suggesting the need for at least disinfection
for small water supplies. Solutions are difficult due to cost
and maintenance considerations. Further, Lzg-ioneZia has focused
new concern on cooling waters (Olson).
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Chemical pollution of water supplies from hazardous
wastes dumps and pesticide use in farming is increasing in the
United States. This is particularly a problem with groundwater
which prior to the introduction of such pollutants required no
treatment before distribution to the public. There is a great
need for early warning monitoring systems which can indicate areas
where potential problems may occur. This type of early warning
system could be extremely useful in talcing active measures to
prevent the contamination of groundwater (Olson).
Concern was expressed that although bacterial and viral
diseases receive wide attention, parasites do not. More effort
should be directed toward the factors affecting the longevity
of such microbes in the environment. Disinfection studies should
be directed to include parasites found in water and wastewater.
One delegate was concerned at possible bacterial or viral pathogenic
presence in nematodes, and the possibility of their passage to humans
via drinking water (Scarpino).
Computer Applications
Discussion with academicians from the United States and
other countries revealed that computerized design of environmental
engineering processes and units are gaining wider acceptance in
teaching and practice (Roy).
Laboratory Techniques
Pretorius at the University of Pretoria,in Pretoria, South
Africa, is advocating the use of water as the liquid phase in capillary
columns to concentrate and chromatrograph volatile organic pollutants
in water samples. He also is working on the development of a
"disposable" gas chromatograph. This instrument, cast in a ceramic
material and about the size of a large pocket calculator, would con-
sist of a single cast unit containing the injection port, a spiral
capillary column and a detector. Because of its low cost, he thinks
it should be cheaper to replace it with a new one rather than try
to fix it or recondition the column. If a disposable gas chromatograph
can really be sold for the approximate cost of the capillary columns,
then it might be a viable product. It certainly would add to the
convenience of on-site analyses and, if mass produced, it would make
gas chromatographic analyses within everyone's capability (Keith).
Toxic and Hazardous Materials
In view of increasing awareness and concern related to the
presence of toxic substances in surface and groundwater sources, and
the anticipated capital investment and operating costs that may be
required for control of these substances, additional research is
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needed to evaluate presently available treatment technology in
reducing concentrations of toxic materials in wastewater. Addi-
tional research is needed to develop low cost treatment processes
(Rohlich).
Much concern was voiced over toxicity evaluations
for potable water and wastewater effluent. Delegates agreed
that a battery of testing is required for toxicity characteri-
zation. Particular significance was given to the need for a
chronic toxicity testing protocol to isolate those chemical
constituents which potentially could cause health effects.
There was consensus over the fact that methodology is in a
state of infancy and, for the most part, insufficient to fully
assess impacts on public health (Englande).
There appears to be a growing recognition of the need to
supplement chemical evaluation of potable water supplies with toxi-
cological testing, both for conventional sources and reuse systems.
At the same time, there seems to be considerable uncertainty as to
the significance of the toxicological test results and their inter-
pretation in assessing the human risks from exposure to such water.
Nevertheless, there are increased efforts in bio-testing the complex
mixtures found in these waters, even when they are poorly characterized
as to chemical content (Andelman).
The question raised most frequently by delegates from the
United States was the validity of certain standards in drinking
water for compounds which are carcinogenic or potentially carcino-
genic as evidenced by mutagenicity. Research should be directed
not only at technical solutions but also at risk-benefit assessment
which can be related to some concrete concepts. The very idea of
what is acceptable risk was debated by many delegates usually
expressing the philosophy of his or her own scientific background.
However, to develop meaningful standards and to manage water pollu-
tion, a consensus is seriously needed. If one could be achieved,
then a better desire for compliance might exist for all agencies
concerned (Olson).
The question is complex, as can be pointed out by the
disagreement on the need for disinfection of effluents or the level
of disinfection acceptable in drinking water supplies. The dif-
ference in attitude between the United States and most countries
in Europe is great. Yet, little discussion ever seems to center on
the meaning of how much disinfection is necessary versus how much
is beneficial for public health. Indeed, I believe this would lead
to very lively discussions among microbiologists throughout the
world. Yet, this bears directly on the problem of trihalomethanes.
Thus, the microbiologist and the chemist now more than ever need to
address such questions in a common forum. The current need for such
a forum is obvious (Olson).
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Inorganic hazardous wastes are routinely disposed of by
landfilling after solidification/stabilization in the United Kingdom.
Several delegates reported that this has resulted in no or only
minimal impact on the environment (Bishop).
Several participants expressed the need for additional
information on health effects of low level concentrations of
toxic substances in water, and the need for low-risk analyses
(Rohlich).
One of the major purposes for many attending the con-
ference was to obtain further knowledge on the extent of employment,
safety, and monitoring of potentially hazardous materials used in
agriculture (e.g., sewage amendment of soil) and feed/food (e.g.,
algal protein concentrate). Another was to gain knowledge of the
extent of, or recent estimates of, the extent of the contamination
of food organisms with anthropogenic toxicants, both organic and
inorganic. There was interest and concern in both of these problems.
There appeared to be increasing interest, for example, in the use
of sewage-derived materials for soil amendment, and the production of
highly proteinaceous substances for feed/food purposes from organisms
(such as algae) grown on toxically contaminated substrates such as
wastewater. However, there did not appear to be concern of comparable
magnitude for the toxic potential of such practices. Indeed, research
focusea on this problem appears to have received minimal support
worldwide. Without thorough knowledge of the toxic potential of
these practices, their continued implementation may be analogous
to the proverbial timebomb (Massaro).
Nitrates
Prince (France) indicated that the city of Paris is
attempting biological denitrification of drinking water facilities.
Apparently, the raw water source for Paris contains nitrates in
excess of 200 mg/£, thus, a need for stable techniques for denitri-
fication of drinking water facilities exists (Neufeld).
Ozonation of Wastewaters
Considerable interest was expressed in the area of ozona-
tion of effluents for disinfection purposes, and for advanced waste-
water treatment purposes. Interest was expressed on the part of
several South Africans in the area of ozonation for modification of
molecular structures from nonbiodegradable residuals to biologically
decomposable substances. Such research may have great impact in
the United States in the development of BAT regulations for the
petrochemical and organic chemicals industries (Neufeld).
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Use of Mathematical Models
The use of models in decision making for solving United
States water pollution control problems could be enhanced by requiring
that confidence limits be stated along with model prediction; that
the appropriate model be used (i.e., not too complex or too simple);
that the user agency be included in model development; and that
adequate model validation be proven. It is not obvious how this
can be done, but tightening the requirements of pollution control
agencies, the obvious one being EPA, would help. Although this seems
contradictory to the current mood for less regulation, it will be
necessary if modeling and the profession are to be credible in the
future (Roberts).
More research in the areas of "black box" models with
real-time data would be desirable. It seems that presently these
models are more used in Europe than in the United States. Research
in modeling the chemistry of anaerobic estuaries was also suggested.
Finally, establishment of a clearing house would aid in avoiding
duplication of effort and could provide a common pool of information.
A workshop on modeling at the next international conference would
be highly desirable (Roberts).
Environmental Control Effort
Out of several informal conversations and discussions,
concern was expressed about the retrenchment or scaledown of
United States water pollution research activities. The belief
was that the United States is the leader, and if it falters, so
will others. It was obvious that they would look to the United
States and EPA, in particular, for leadership in pollution con-
trol (Scarpino).
State-of-the-Art Consensus Papers
Extensive discussion takes place at each conference
concerning the interpretation and application of research dis-
coveries to practice. Many delegates differ in their experience
with regard to how and when to make certain research applications.
Different research engineers and research scientists draw dif-
ferent conclusions from the same set of facts. If those who
create the facts differ in their interpretation, consider the
problems of the consultant who tries to apply them in his practice.
Alexander (South Africa) commented that, in his opinion, the
biggest gap in technology transfer is the lack of "comprehensive
state-of-the-art papers" (Baumann).
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Professional societies, government regulatory agencies,
consulting engineers, and educators could provide a significant
improvement in technology transfer if they would develop "state-
of the art papers" on water and wastewater treatment processes
and models on which there is common agreement. These could be
developed and published in the same manner as-Standard Mvtkod& (,o\
Examination WcuteA. and. WcutmateA is developed. The development
of example problems showing all calculations involved in the inter-
pretation and application of processes (together with sensitivity
calculations for expected variations in assumed constants and
coefficients) would aid in bringing process fundamentals to the
engineer, scientist or operator who has to make it work (Baumann).
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APPENDICES
Number Description Page
I PROGRAMME: 11th Conference of the Inter-
national Association on Water Pollution
Research (IAWPR) 282
II Memorandum: Development of Report for
EPA on IAWPR Cape Town Conference 306
III Assignments—Participants in USANC Project 310
IV Memorandum: Assignments for Development of
USANC Report on Cape Town Conference 312
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APPENDIX I
11TH CONFERENCE
OF THE
INTERNATIONAL ASSOCIATION ON
WATER POLLUTION RESEARCH
(IAWPR)
CIVIC CENTRE
CAPE TOWN
29 March - 2 April 1982
"282"
-------
CONTENTS
Page
Scheduled events 3
Opening Ceremony 5
Technical Programme (including technical visits) 6
Special note Timetable for technical programme on
Tuesday, 30 March 16
Bnefing sessions for authors, session chairmen, recorders and
invited discussers 16
Important note for authors-Slides for projection i 16
Poster presentations 17
Special technical visits dunng conference 19
Programme for accompanying persons 19
Social functions 21
Post Conference Seminars 21
Timetable for buses 22
General information 25
Acknowledgements 27
Office bearers 28
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SCHEDULE OF EVENTS
NOTES: 1 The programme lor accompanying persons is not included
here, but is given on p 19
2 A bus service will be provided to and from hotels which are
not within easy walking distance from the various venues
The bus timetable is given on p 22
SUNDAY 28 MARCH
09h30 Depart from Civic Centre on tours PCT 4 (Cape Point) and
PCT 5 (Hermanus)
15h00 Depart from Civic Centre on tour PCT 3 (Orientation)
16h00-18h30 Registration (mezzanine level, Civic Centre)
19h00-20h30 Meet and greet reception, hosted by the Water Research
Commission, in the Venetian Room. Heerengracht Hotel
MONDAY 29 MARCH
07h30-08h30 Registration (mezzanine level, Civic Centre)
08h45 Delegates to take up seats in the Nico Malan Theatre
(adjacent to Civic Centre) for Opening Ceremony
09h00-10h30 Opening Ceremony in Nico Malan Theatre (for programme
seep 5)
10h30-1 IhOO Tea/coffee at Civic Centre
11 h00-11 h45 Poster presentations* Civic Centre (mezzanine level)
11 h45-17h35 Technical sessions. Civic Centre
19h00-20h15 Civic reception. Civic Centre concourse
TUESDAY 30 MARCH
08h30-16h35 Technical sessions. Civic Centre
16h40 Buses depart from Civic Centre for braaivleis (barbecue) at
Bien Donnd expenmental farm near Paarl
WEDNESDAY 31 MARCH
08h30 Buses depart from Civic Centre for technical excursions T1
to T6 (seep 10)
Evening Free
or
Spend the evening with a South Afncan family (Overseas
delegates only**)
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THURSDAY 1 APRIL
09h00-l7h35 Technical sessions Civic Centre
19h30-23h00 Conference banquet at Good Hope Centre
FRIDAY 2 APRIL
09h00-l7h35 Tecnnical sessions Civic Centre
I7h35-I9h00 Cheese and wine farewell function (Civic Centre)
' Additional periods for poster presentations are listed in the technical programme
" The Caoe Town Overseas Hospitality Club extends a friendly invitation to all overseas
delegates to spend an evening with a Soutn African family Overseas delegates inte-
rested in this invitation should contact tne Registration Desk for further particulars on
MONDAY 29 MARCH 1982
-285-
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OPENING CEREMONY
(NICO MALAN THEATRE)
MASTER OF CEREMONIES: Mr P E Odendaal Chairman
Conference Organizing
Committee
MUSIC: Nicola Petrovic Trio
08h45 Delegates to take up seats
MUSICAL INTERLUDE
09h00-10h30 Opening ceremony
PROGRAMME
Welcoming address His Worship the Mayor of Cape Town Alderman M J
van Zyl
Welcoming representatives of individual countries Master of Ceremonies
Opening Address Dr C F Garbers. President of the Council for Scientific and
Industnal Research
Address by Conference President Or G J Stander
MUSICAL INTERLUDE
Address by IAWPR President. Prof R S Engelbrecht
Confernng IAWPR honorary membership on Prof S Iwai. Japan
Announcements
-286-
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TECHNICAL PROGRAMME
(INCLUDING TECHNICAL VISITS)
Techncal sessions will be hetd at the Civic Centre m the
Mowing three halls
Hall A Ground Door (Small Theatre)
Hall B Ground floor (Podium Hall)
Hall C Mezzanine level (beyond registration and poster area)
MONDAY 29 MARCH
I0h30-l ihOO Tea coflee at Civic Centre to be served immediately alter the Opening Ceremony
1 lhOO-11M5 Posters (exhibited m area adjacent to registration on the mezzanine level)
HALL A
Chairman: E C Reed (UK)
Recorder JSxfiwcklUK)
11M5-I2ft30 Pi The Effect of Submanne Wastewater Discharge
on the Bacterial Quality of Surf Waters - D J
Umgstone ISA)
Invited Discusser. B H Olson (USA)
HALL B
Chairman. C F Seyfned (FRG)
Recorder. P Wo)) /FRG)
P2 The Effect of Aeration Basin Configuration on
Activated Sludge Bulking at Low Organic Loading
-SELee BLKoopman DJenkins RFLewis
(USAI
Invtted Discusser: WC Boyle (USA)
HALL C
Chairman W J Weber [USAI
Recorder: LD Lash (USA)
P3 Development ol Water Reclamation Techncrtogy m
South Atnca-/UCteyron LRJvan Vuuren B
Rout (SA)
tnvtted Discusser: RDHeaton(USA)
12h30-Mh00 LUNCH
13M5-14H00 PRESENTATION OF POSTERS S1 - S20
Chairman. EC Reed
Recorder. JSriwick(UK)
14h00-i 4M5 P4 Surface Dilution ol Round Negative Buoyant Jets
- A Comparison with Other Jets - G
Noutsopoutos J Demetnou (Greece)
tnvtted Discusser.
14h50-15h35 P7
The Distribution and Sqniteance ol Tone Metals
in Sharks from the Natal Coast South Africa-fl
J Witting HR Watting RC Stanton TP
UcCturg EMEngeSxechl(SA)
Imfted OltcutMr: E J Massan (USA)
Chairman C F Seyfned (FRG)
Recorder. P Wotl (FRG)
P5 Obtaining Secondary Treatment with
RBC Underflow Clanfiers - / L Bogen (USA)
Invited Discusser: AHMolof(USA)
P8 Optimization of Nitrogen Removal in the Single
Studge Actuated Sludge Process -AC van
Haandel PL OohS G v R Mir ass (SA)
hvflad Utaam: Y Matsuo (Japan)
P6
Chairman. W J Weber (USA)
LD Lash (USA)
Removal of Potential Carcinogens and Toxicants
by Treatment Systems lor Direct and Indirect
Reuse ol Wastewater Evaluated by means ol a
Hamster Cell Culture Assay -RKtir OW
Pronsky(SA)
Invited Discusser. J B Andelman (USA)
P9 Organc Moopotuton of Potable Water Supplies
- Indirect versus Direct Reuse - J f J van
Rensturg S J Them AJHassett PGvan
Rossum(SA)
Invited Discusser: SDWaDe (USA)
15h35-16h00 REFRESHMENTS PRESENTATION OF POSTERS S2t - S40
Chairman: E JHaD(SA)
Recorder: LRJVanVuuren(SA)
16NXH6M5 PtO Baselme Studies and CcmuousMontcmg lor a
Shallow Tropeal Bay Receiving Nrkel Refinery
Effluent-JECarey UAPent WSRooney. TL
jujet (Australia)
Invtted Discusser: R B Clarh (UKt
16h50-l7h35 P13 Influence ol Discharges Irom Storage Reservows
on the Tastes and Odours Appearing m the Seme
and Marne Rivers - URaet J Ukmchet (France)
Invtted Discusser: RGehr (Canada)
Chairman1 L Com (France)
Recorder. C Gomel la (France)
P11 Fate of Heavy Metals and Potential tor Clinker
Formation during Pilot Scale manerason of
Municipal Studge - H W Campbell. P J Cmscuob.
TRBndle (Canada!
Invited Discusser. AGerber (SA)
P14 The Use of Rheology lor Sludge Charactenzaton
- hw Campbell PJCrescuolo (Canada)
tnvtted Discusser. Marcnandae (France)
-287-
Chalnnan: A Van Haute (Belgium)
Recorder: WMasscheiem (Belgium)
Pl2 The Econom* Impact on an urban Industrial
Complex of Mineral Pollution m the Water Supply
-ACaseStudy-JJCHeymke SFMcCuDocti
(SA)
bwttad Discusser. C Herotd (SA)
Pt5 UmnologcalEltects of the Elimination of
Phosphorous from the Wahnbach Reservoir - H
Bernhardt J Clasen (FRG}
Invited Discusser. C Basalo (France)
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TUESDAY 30 MARCH
HAIL A
HALL B
HALL C
Chairmen- W A Bndgeo (Canada)
Recorder. R Gehr (Canada)
08h30-09hi5 Pi6 NewMethodslorAnalysingWaterPollutants-L
HKeitti RCHall RCHamsel1 RGLandoKJE
Henderson (USA)
Invited Discusser: JF J VanRensburg(SA)
09M20-I0h05 P18 Simultaneous m situ Determination of Dissolved
Cases by Gas Chromatography II Oxygen and
Nitrogen in Activated Sludge Process Streams - T
Blstad ENUghtfoot (Norway USA)
Invited Discusser P G Van Rossum ISA)
Chairman J Matsumoto (Japan)
Recorder. Y Watanabe (Japan)
PI7 Stow Sand Filtration (or Cercanal Control in North
Cameroon Village Water Supply - K Kawata
(USA)
Invited Discusser. P Williams (SA)
P19 Characterization of Fouling Potential for Pressure-
Driven Membrane Processes A New Simulated
Flow CeO - fl H Reed G Beitort (USA)
Invited Discusser1 E S K Chian (USA)
STATE-OF-THE-ART
THEME t THE USE OF MATHEMATICAL MODELS
Convener AGeroeriSA)
Recorder- C Basab iFrancei
(a) Review and Background -AGerbertSA)
lb) Application to Estuanne & Coastal Waters - A L
GamesoniUK)
(c) Application to River t Underground Waters - J
Dmcti (Belgium)
Id) The Use ol Modelling in Management Decisions -
PA Krenkelt TOBarnwell(USA 1
(e) Mathematical Modelling ol Estuaries and Coastal
Waters - A James 1UK1
DISCUSSION
Invited Discusser RBnggsiUKi
I0h05-t0h30 REFRESHMENTS PRESENTATION OF POSTERS St -S20
Chairman- M ChaudJnjn (India)
Recorder P Coombs (SA)
I0h30-lihl5 P20 Nutnents Removal ana Recovery m a Two-Siage
High-Rate Algal Wastewater Treatment System -
GSheiel UA:ov R Moraine (Israel)
Invited Discusser. DAlbrecht(FRG)
Chairman: WHJHattingh(SA)
Recorder. EOttman(FRG)
P21 Desalination by Continuous Ion Exchange Based
on Theimaliy Regenerable Magnetic Meroresws -
B A Botto E A Swrnton (Austraia)
Invited Discusser: A D Canr (SA)
STATE-OF-THE-ART
THEME 1 THE USE OF MATHEMATICAL MODELS
CONTINUATION
1 ih20-i2WJ5 P22 Operational Management ol Pollution incidents -
The Thames Way UK-f CReed MCDar)
(UK)
Invited Discusser: P R Philip (France)
P23 Continuous Coumer-current Ion Eichange for
Desalination and Tertiary Treatment of Effluents
and Other Brackish Waters -BA Hendry (SA)
Invited Discusser M J Semmens (USA)
I2h05-I3h00 LUNCH
12h3S-t3hO0 PRESENTATION OF POSTERS S21 - S40
Chairman DHNewsomelUK)
Recorder- G Eden (UK)
13h00-l3h45 P24 Viability and Adaptability of E Cob and
Enterococcus Group to Salt Water with High
Concentration ol Sodium Chloride - T Omura M
Onuma Y Hashimoto (Japan)
Invited Discusser:
I3h50-Mh35 P26 Chtonne-ResistanceotCoiitorm-iestedBactena
Isolated from Raw and Treated Sewage Effluents
-i. YCLeong DOtsana HFRidgway BH
OtontUSA)
Invited Discusser J Via) IFrancei
Chairman HBlersch(SA)
Recorder. J R Simpson (UK)
P2S On the Mass Transfer Charactenstics Within
Microbial Systems -M Onuma T Omura (Japan)
Invited Discusser WJGrenneyiUSA)
P27 The Scale-up and Limitation of Physical Oxygen
Transfer m Rotating Biological Contactors - B J
Km AH MM (USA)
tnvtted Discusser. PL Bishop IUSA|
t4h3S-1Sh00 REFRESHMENTS PRESENTATION OF POSTERS S2t - S40
Chairman. HLeskela (Finland)
Recorder: PLehmusluotoiFmland)
tSh00-tSh4S P28 Ozonation ol Aromatic Compounds pH-
Dependence - E Gilbert (FRG)
Invited Discusser. M Schalekamp (Switz |
I5h50-t6h35 P30 Presence of Phenota Compounds m Sewage
Effluent and Sludge trom Municipal Sewage
Treatment Plants-FBde Walte DA Kaonan D
Russell D Norman S K Chan (USA)
tnvttad Discusser: D W Osbom (SA)
Chairman. J E Lmd (Swedeni
Recorder. B Encsson iSweden)
P29 Application of the Marais-Ekama Activated Sludge
Model to Large Plants -HA NcMts (SA)
hvttad Discusser: W W EckenWder (USA)
P31 A Mathematical Model ol Biological Punficaton m
Aerated Activated Caton Botiiters - G Martin A
YieRoui P Schubl (France)
Invited Discusser GEdentUK)
STATE-OF-THE-ART
THEME 2 OIL POLLUTION IN MARINE AND
FRESHWATER ENVIRONMENTS
Convener N King (UK)
&: D C Madeod (SA)
(a) Review and Background - NKmgiUKi
(b) Legal & Administrative Control -AD Read (UKI
(c) Sources ol Oil Pollution- FGPayneS MT
Wesiaway(UK)
(d) Economic Aspects of Oil Pollution -HPLuhr
(FRG)
(e) Effects of Oil Pollution and Research Needs - RB
Clark (UK)
(f) Methods ol Treatment - F Beme (FranceI
DISCUSSION
STATE-OF-THE-ART
THEME 2 OIL POLLUTION IN MARINE AND
FRESHWATER ENVIRONMENTS
CONTINUATION
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WEDNESDAY31 MARCH
FULL DAY TECHNICAL VISITS
NOTES
1 A ctrace ot sa options. T1 to T6 hat) been presented to
delegates and each delegate had indicated his first three
choices in order ol pnonty on the registration form In allo-
cating places on the tours, delegates lirst choices have as
far as possible been adhered to As certain ol the tours
have been oversubscribed however some delegates have
been placed on tours of their second or third choice
2 IMPORTANT Symbols ranging from T1 to T6 will appear
on the name lag which each delegate will receive on regis-
tration These numbers will correspond with the tours on
whch delegates have been placed and they must board a
bus with ihe corresponding number when the tour buses
depart Irom the Cr/tc Centre
3 A booklet providing inlormaton and lechmcal details ol the
various installations to oe covered by all six tours T1 to
T6 will be included in the material which delegates will re-
ceive on registration REMEMBER TO BRING THIS
ALONG ON THE TOURS
4 Boxed lunches will be orovtded on the buses at no ad-
ditional cost to participants
T1 PAARL SEWAGE WORKS
08h00 Pick up at hotels
08h30 Depart Cwc Centre
09h45 Arnve Paarl Sewage Worts for plant visit
Hh30 Travel to Cape Flats lunchonbus
12h30 Visit Cape Rats Sewage Works and experimental
reclamation plant
14h30 Return to hotels via scenic route (aboul 2 hours)
T2 STEENBRAS WATER TREATMENT PLANT
OShOO Pick up at hotels
08h30 Depart Civic Centre and travel via scene route to
Gordons Bay
11 h 15 Visit Sieenbras Water Treatment Plant
12h05 Lunch at Steenbras Dam
1JM5 Travel to Cape Fiats
14h30 Visit Cape Flats Sewage Works and expenmental
reclamation plant
I6h30 Return to hotels (about 40 mm |
T3 BELLVILLE SEWAGE WORKS
OShOO Pick up at hotels
08h30 Depart Civic Centre and travel via scenic route
10h30 Visit Cape Flats Sewage Worts and expenmental
reclamation plant
12M30 Lunch at Zeekoevlei
13h30 Depart for BelKnlle Sewage Worts
I4hi5 Arnve BetMle Sewage Works lor plant visit
I6hi5 Return to hotels (about 40 mm)
T4 INSTITUTE OF SEA FISHERIES
OShOO Pick up at hotels
08h30 Depart Cwe Centre
09hi5 Amve Cape Flats for visa to Sewage Worts and
expenmental reclamation plant
I0h30 Travel via scene route with stop tor lunch
14h00 Visit Institute ol Sea Fishenes (Sea Point) and
Research Vessel (Cape Town Harbour)
I6h30 Return to hotels (about 15 minutes)
T5 UNIVERSITY OF CAPE TOWN
OShOO Pick up at hotels
08h30 Depan Cive Centre
091115 Amve Cape Flats for visn to sewage worts and
experimental redamatnn plant
I0h30 Travel via scenic route with stop tor lunch
14h00 Visit University (Departments olOvil and Chemical
Engineering)
!6h00 Return to hotels (about 20 mm)
T6 K0E6ERG-MILNERT0N
OShOO Pick up at hotels
08h30 Depart Civk Centre
09h00 Visit Koeberg Nudear Power Stabon
tOhiS Travel to Miinerton
10h30 Visit Miinerton Sewage Works
Hh45 Travel to Cape Flats with lunch on bus
12h30 Visit Cape Flats Sewage Works and expenmental
reclamation plant
14h30 Return to hotels via scene route (about 2 hours)
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HALL A
Chslrmsn: A M Wachs (Israeli
Recordw: E kWwtdi (Israel)
09h00-09M5 P32 An Appraisal ol the Performance ol a Continuous
Automatic Fish Bomonitonng system ai an
Industrial Site - W SG Morgan PCKuhn B
Aits. G Walls ISA)
Invited Discusser. TYosfoda (Japan)
HAU B
Chairman: T L Judeli (Australia)
Recorder W Raper (Australia)
P33 Granular Activated Carton and Preownated
Granular Activated Carton Treatment tor
Biologically and Physieally-Chemically Treated
Wastewater Effluents - A Metier J L Mcttutt
(USA)
Invited Discusser. W J Weber (USA)
09h50-10h35 P34 Examination ot a Dnnlimg water Supply lor
Mutagenicity-PGvanRossum jMWflemse
C Hiber L Alexander (SA)
Invited Discusser
P35 The Nature ot the Reactons Between Chlonrte
am) Purine and Pynmidine Bases Products &
Kinetes-J/'Goutf TR Hay (USA)
Invited Discusser. C W Randall (USA)
10h35-11h00 REFRESHMENTS PRESENTATION OF POSTERS S21 - S40
Chsirman- A H Munu (Spam)
Recorder. F M Bardaji (Spain)
Ilh00-I1M5 P36 Depositional Process ot Fine Sediments - T
Kusuda TUmita KKoga HYorozu YAwaya
(Japan)
Invited Discusser. C Davis (SA|
Chairman. HI Shuvai (Israel)
Recorder. M Patrick (N Zealand!
P37 The Fate o< Some Metal Species Lead
Cadmium Zinc in Surface Water Dunng Biological
Sand Filtration - Effects of Preozonation -FE/b
DDelabre J C L Hopnautt A Philippo P Thomas
A Bnce (France)
Invited Discusser.
Mh50-12h35 P38 Nutrients and Algal Growth m an Impounded
River Consequences lor its Oxygen Balance and
Nutnent Control Strategy -KRImhott
D R Albrecht iFRG)
Invited Discusser. Casteignau (France)
P39 A New Configuration ol the High-lime Process
with Sludge Recirculation lor Magnesium
Recycling - EkJeksviich A M wachs (Israel)
Invited Discusser B A Bell (USA)
I2h35-14h00 LUNCH
13h1S- 14h00 PRESENTATION OF POSTERS St-S20
Chairman' T Bilstad (Norway)
Recorder P H Jones (Canada)
14h00-l 4M5 P40 Impact ot Nudear Power Plants ol the P WR-type
on River Quality - WJUasscheiem J Genet
(Belgium)
Invited Discusser L Henry (Australia)
Chairman H W Campbell (Canada)
Recorder. A S Almeida (Brazil)
P41 An Integrated Low Cost System lor Treatment ol
Potato Processing Wastewater Incorporating
Anaerobic Fermentation and Phosphorus Removal
- J G Parker B J Lyons. C D Parker (Australia!
Invited Discusser B Ericsson (Sweden)
14h50-l5h3S P42 Fractional Composition ol Phosphorus Forms in
Sediments Related to Release -HFunmai S
Qhgaki tJapan)
Invited Discusser. C A Bruwer (SA)
P43 The Adsorption Behaviour ol Catione
Polyeiectrofytes in Dissolved Air Flotation - R
Getir J G Henry (Canada)
Invited Discusser. B M Van Vliet ISA)
15h3S-16hOO REFRESHMENTS PRESENTATION OF POSTERS S1 - S20
Chairman. K R Imhotl (FRG)
Recorder. HPLuhr(FRG)
16hOO-16M5 P44 The Influence ol Sediment Waler Interactions m
an Impoundment on Downstream Water Quality -
TJGmzard CW Randall E M Jennelle (USA)
Invited Discusser. W H J Hamngh (SA)
l6hSO-l7h35 P46 River-Basin Planning lor Control of Nitrate
Pollution-CSS/moff DG Jameson (UK)
Invited Discusser HCPreuHUSA)
Chsirman. R Chalmers (UK)
Recorder J G Parker (Australia)
P45 The Performance ol an Ultrafiltration Pilot plant lor
the Closed Loop Recycling ol Textile Desizmg
Wiuents-CA Buckley RBTownsend R
Groves (SA)
Invited Discusser. A Neuer (USA)
P47 Leaching Characteristics of industrial Metal
Finishing Wastewater Treatment Plant Sobds - T
H Gowgame P W Barnett (USA)
Invited Discusser JWFunkelSA)
HAU C
STATE-OF-THE-ART
THEME 3 THE ECONOMICS OF WATER POLLUTION
CONTROL & RESEARCH
Convener- G Rjncke (FRG)
Recorder K Poppmghaus (FRG)
(a) Review and BacJiground - G Rmcke (FRG)
(b) Funding Water Pollution Control in South Africa -
J A Lusher (SA)
(c) Funding Water Pollution Research - G Rchkh
(USA)
(d) Balancing Benefits 4 Expenditure - C Letrou
(France)
DISCUSSION
Invited Discusser. R ACanhamiUSAi
STATE-OF-THE-ART
THEME 3 THE ECONOMICS OF WATER POLLUTION
CONTROL 4 RESEARCH
CONTINUATION
STATE-OF-THE-ART
THEME 4 TECHNOLOGY TRANSFER
Convener S H Eberfe (FRG)
Recorder MRHeruen(SA)
(a) Review and Background-SHE&erfe/FHGI
(b) Scale-Up Problems - J Sidwidi (UK)
(c) The Role ol Consultants-IV Eckenleider (USAi
(d) Involving Practitioners m Research - P E
Odendaai(SA)
(e) Packaging of Information -MJ Pieterse iSAi
(l| Role ol Equipment Manufacturers - J Bernard
IFrance)
DISCUSSION
Invited Discusser- W Von der Emde (Austria)
STATE-OF-THE-ART
THEME 4 TECHNOLOGY TRANSFER
CONTINUATION
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FRIDAY 2 APRIL
HALL A
Chiirmsn I Hespannoi (Spam)
Recorder' R Ludwg (Brazd)
09h00-09h45 P48 Virus Removal by Fillralfon-hi Snramulu
MChauihm(Ma)
Invited Discusser. L Y C Leong (USA)
HALL B
Chairman: W Vonder Emde (Austria)
Recorder H Kross lAustna)
P49 Aerobic Thermopnilic SlabilLzaton of Sludge
Versus Anaerobic Digestion and Other Kinds ot
Sludge Treaimcni at Middle-sued Plants with
Respect to Power Conservation and Economy - P
mt(FRG}
Invited Discusser. J Bernard (France)
09ft5(M0H35 P50 Enterovirus Concentration using Automated Hollow
Fiber Ultrafiltration - G BeHon A Patuszek
LSSturmanlUSA)
Invited Discusser 0 J Sproul (USA)
tOh3S-llhOO REFRESHMENTS PRESENTATION OF POSTERS S1 - S40
Chairman: G Belfart (USA)
Recorder. J F J Van Rensburg (SA)
HH00-11M5 P52 A Comparative Study ol Methods for
Concentration ol Human Enteroviruses -MT
Martins f Marques IA Soa/es /Bras!)
Invited Oiscusser- E Mupen (SA)
iihXM2h35 P54 A New Large Scale Technique lor Quantitative
Recovery ol Enteroviruses by Adsorption on
Suspended Glass Powder Application to Surface
and Dnnkrng Waters ol the Pans Area -PH
Vitagmes BSarrets CDanglot ft Vdagmes
(France)
Invited Diicuuc. . 0 Roy (USA)
P51 Simultaneous Pasieunsation-Dgesoon (SPD-
Process) - 6 Kugel (FRG)
Invtted Discusser. S Barnes (UK)
Chairman. J P Matthews (UK)
Recorder: C S Sinnott (UK)
P53 Inhibition Modelling m Anaerobic Digestion-AC
Duana GK Anderson (Portugal UKI
Invited Discusser. G v fl Maras (SA)
P55 Process Integration m Sludge Management-fl/
Dick OL Simmons YHa&IUSA)
Invtted Discusser G Kuget (FRG)
HALL C
STATE OF THE ART
THEME 5 WATER POLLUTION CONTROL IN
DEVELOPING AREAS
Convener PH Jones (Canada:
Recorder
(~) Review and Background -PH Jones fCanadal
(~) Institutional Arrangements and Funding - B
Hswermn iSwedenj
(c) Training and Education - K Pooomgnaus iFRGl
(dl Low Cost Technology- GGCtihelSA!
(e| Ptoblems ana Needs -JRSimpson
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SPECIAL NOTE
TIMETABLE FOR TECHNICAL PROGRAMME ON TUESDAY 30 MARCH
Please note that the timetable for the technical programme on Tuesday 30
March had to be adapted in order to allow an early afternoon departure for the
Bien Donng function
The first session will commence at 08h30 instead of 09h00 and the lunch
period will be 55 minutes instead of 85 minutes The last session will therefore
conclude at I6h35 instead of 17h35 Please also note the amended times for
briefing sessions
BRIEFING SESSIONS FOR AUTHORS,
SESSION CHAIRMEN, RECORDERS AND
INVITED DISCUSSERS
Briefing sessions for authors, session chairmen, recorders and invited dis-
cussers. will be held each day in the specific halls in which they will present
their papers or do duty on that day The briefing penods will commence at the
following times
The persons who will lead the briefing sessions in the three halls are
IMPORTANT NOTE FOR AUTHORS: SLIDES FOR
PROJECTION
1 Authors should hand their slides to the technician on duty in the hall
where they will present their papers immediately before the start of the
session during which they will make their presentation. Authors
should collect their slides and check them at the end of the session
2 A slide viewing room will be available next to the Podium Hall (Hall B)
for authors who wish to screen or examine their slides beforehand
Monday 29 March
Tuesday 30 March
Thursday 1 Apnl
Friday 2 Apnl
08h00 and 12h30
08h30 and 13h30
08h30 and 13h30
11 hi 5
HALL A
HALL B
HALL C
Phil Coombs
Keith McCusker
Piet Odendaal
-292-
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POSTER PRESENTATIONS
Authors of posters presentations will be on duty at the times indicated in the
technical programme In addition, special appointments can be made with
authors on appointment pads which will be available on each author's table
The following posters will be exhibited on the mezzanine level in the area ad-
jacent to registration
51 Removal of Pesticides and Herbicides by means of Adsorption on Acti-
vated Carbon
0 V Heroes (Belgium)
52 Computer Control in a Sewage Plant, Methods and Expenence
C P Kuznia (FRG)
53 Adsorption and Biodegradation of Linear Alkylbenzene Sulfonates (LAS)
by Activated Sludge
K Yoshimura, A Nakae (Japan)
54 The Application of Pre-Treatment Procedures to Limit Membrane Foul-
ing in Reverse Osmosis Reclamation of Secondary Sewage Effluents
H A de Vilhers. G R Botha, M H Wnght (South Afnca)
55 Flotation as the Final Clarification Step in Wastewater Treatment and its
Influence on the Oxygen Balance of Receiving Waters
K.P. Kiefhaber, U Neis. J Weber (FRG)
56 The Disposal of Sewage Sludge by Land Spreading
J H Nell, J F P Engelbrecht (South Afnca)
57 Total Mercury Concentrations in some Species of South Afncan Com-
mercial Manne Fish
J. Henry (South Afnca)
58 Toxicity Testing of South Afncan Oil-Spill Dispersants.
A Moldan, P Chapman (South Afnca)
59 Effect of Oil on Reproductive Capacity of Callianassa Kraussi
Lynn F Jackson (South Afnca)
510 The Use of Ultraviolet Absorption in the Measurement of Fish-Factory
Pollution
P Chapman (South Africa)
511 The Survival of Bactenal Indicators in Lysimeters and Landfills
J A Donnelly, P V Scarpino. D. Brunner (USA)
512 Effect of Ionic Presence on Chlonne Disinfection of Animal Viruses
S Cromer, P V Scarpino. C Wells (USA)
513 Interactive Water Quality Simulation of the Han River using Computer
Graphics
Y Chung, P N. French, P Loucks (Korea, USA)
SI 4. Polyelectrolyte Toxicity Tests by Fish Avoidance Studies
L 0 Spraggs, R Gehr, J Hadjmicolaou (Canada)
S15 Mineralisation Problems in the PWV Complex - The Identification of Vi-
able Solutions by means of a Suite of Deterministic Models
C E Herold (South Afnca)
-293-
-------
Si 6 A Chemical Investigation of a marine Sewage Outfall
P D Baniett. G A Eagle (South Afnca)
517 The Location and Nature of Accumulated Phosphorous in Activated
Sludge
L Buchan (South Africa)
518 Microbiology of Nutrient Removing Activated Sludge
Margaret A Hart. LeahN Melmed (South Africa)
519 Nutrient -Salinity Relationships m Four Estuaries of the Cape Province,
South Africa
G A Eagle, P D Bartlett (South Africa)
520 The Role of DOC and TOH Measurements in Water Pollution
R A van Steenderen (South Africa)
521 Aspects of the Performance of Final Clarifiers in the Activated Sludge
Process
C Oavies (South Afnca)
522 Flux of Cadmium through a Laboratory Food Chain (Media-algae-mus-
sel) and its Effects
HF-KO Hennig MJ Orren(SouthAfrica)
523 -
524 The Impact of Diffuse Atmospheric Nutrient Loading on an Oligotrophy
Freshwater Lake in a Developing Urban and Industrial Area (Richards
Bay. South Africa)
CGS Archibald, M S Muller (South Africa)
525 Interstitial Meiofauna as Indicators of Sandy Beach Pollution
T P McClurg (South Africa)
526 Production of Algal Protein in Raw Sewage
J M P Viviers E Sandbank. L R J van Vuuren A Gerber
(South Africa)
527 The Enumeration of Streptococci and Mycobacteria Present in Landfill
leachate
J A Donnelly. P V Scarpino. D Brunner (USA)
528 Some Aspects of the Sensitivity of juvenile Jasus Lalandu to the Water
Soluble Fraction of Crude Oil
S R Lipschits (South Africa)
529 Ecotoxicological Evaluation of an Oil Gelling Agent - its Effect on Photo-
synthesis ol Seaweed
T Yoshida, T Maruyama. H Kojima (Japan)
530 The Measurement of Organic Pollution of the Sea using Satellite Imag-
ery
L V Shannon. N M Walters. AGS Moldan (South Afnca)
531 Exhaustive Recyclic Use of Water in the Food Industnes
R A Gallop. A W Hydamaka. B J Clark. L B Carvalho (Canada)
532 Precipitation of Calcium Phosphate and pH-elfects in Denitrifying Bio-
films
E Arvin. G H Knstensen (Denmark)
-294-
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533 Biochemical Changes Associated with Luxury Phosphate Uptake in a
Modified Phoredox Activated Sludge System
0 J J Potgieter, B W Evans (South Afnca)
534 L F B - Full Scale Operation
D S Render (South Afnca)
535 Suppression of Density Waves in Clanfiers
M C Murphy, R R Hudgins, P L Silveston (Canada)
536 Parasites in Southern United States Sludges and Disinfection by Stan-
dard Sludge Treatment
R S Reismers, M D Little, A J Englande, D B Leftwich, D D Bow-
man, R F Wilkinson (USA)
537 Water and Wastewater Treatment with Reusable Magnetite Participles
N J Anderson, B A Bolto, D R Dixon, L O Kolank, A J Priestley.
W G C Raper (Australia)
538 A System Developed (or the Treatment of Tanning and Fellmongery
Effluents
S D Roets (SA)
539 Research into the Mass Culture of Algae in Closed Systems.
R D Walmsley, S N Shillinglaw, D Geldenhuys (SA)
540 Utilization of Computenzed Water Monitonng and Information System
E Ottmann (FRG)
SPECIAL TECHNICAL VISITS DURING
CONFERENCE
Delegates who. on their registration forms, indicated interest in special techni-
cal visits dunng the conference, are requested to report at the 'Special Tours
desk on Monday 29 March. They will then be informed of arrangements
As these visits take place by special arrangement only, it may happen that the
timing of a specific visit will not suit all the delegates who expressed interest in
participating
PROGRAMME FOR ACCOMPANYING
PERSONS
All registered accompanying persons are entitled to
• attendance at the opening ceremony, followed by a short dnve to Blou-
bergstrand for lunch.
• attendance at all the social functions Apart from the banquet these social
functions are free of charge
• free transport between hotels and venues for social functions
Reservations and payment for sightseeing tours L 1 - L 4 should have been
made beforehand
-295-
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MONDAY 29 MARCH
08h00 Pick up at GROUP A & B hotels* for Opening Ceremony at
Nico Malan Theatre
09h00-10h30 Opening Ceremony
10h30-1lh00 Tea/Coffee at Civic Centre
11 hOO Depart from Civic Centre for lunch at Blue Peter, Blouberg-
strand.
Expected time of return to hotels I5h00
TUESDAY 30 MARCH
09h00 Pick up at GROUP A & B hotels' for Tour L 1 (Wine route)
09h30 Depart from Civic Centre on Tour L 1 Travel via Mitchell s
Plain (new housing development where tea will be served),
along the False Bay coast to Stellenbosch Lunch at Lanserac
Hotel. Continue tour of Stellenbosch (tea at Oude Libertas)
then travel via Hellshoogte mountain pass to Bien Donne' (ex-
pected time of arnval 17h30) to |Oin conference delegates for
South Afncan braaivleis (barbecue)
WEDNESDAY 31 MARCH
09h00 Pick up at GROUP A & B hotels* for Tour L2 (Mountain
Passes)
09h30 Depart Civic Centre on Tour L2 Travel over Du Toil's Kloof
pass (tea at Protea Park in the pass). Continue to Worcester
(lunch at Klemplasie) Proceed via Villiersdorp and Elgin to Sir
Lowry's Pass Tea at Van Riebeeck. Gordons Bay Expected
time of arrival at hotels 17h30
THURSDAY 1 APRIL
09h00 Pick up at GROUP A & B hotels* for Tour L.3 (Kirstenbosch)
09H30 Depart Civic Centre on Tour L 3 Visit Kirstenbosch botanical
gardens where tea will be served Proceed to Groot Constantia
homestead Expected time ot return to hotels 13h00
FRIDAY 2 APRIL
09h00 Pick up at GROUP A & B hotels* for Tour L 4 (Cape Point)
09h30 Depart Civic Centre on Tour L4 Travel via Hout Bay (tea at
Suikerbossie) to Chapman s Peak drive, and then via Fishhook
and Simonstown to the Cape of Good Hope Nature Reserve
and Cape Point Return via Kommet|ie and the "Old Cape
Road" (lunch at Alphen Hotel, Constantia). Expected time of
return to hotels 17h00 Those who wish to attend the cheese
and wine farewell function (17h35—19h00) can alight at the
Civic Centre
* See timetable for buses, p 22.
-296-
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SOCIAL FUNCTIONS
All registered delegates and registered accompanying persons are cordially
invited to attend the social functions Apart from the banquet, these social
functions are free of charge
Sunday 28 March
Monday 29 March
Tuesday 30 March
Thursday 1 Apnl
Friday 2 Apnl
19h00-20h30 Meet and Greet Reception.
Heerengracht Hotel
19h00-20h15 Civic Reception *
Civic Centre
18h00-23h00 Braaivleis (barbecue) at
Bien Donn6 Expenmental Farm.
PaarT
19h30-23h00 Banquet
Good Hope Centre
(Cost R25 per person)
17h35-19h00 Cheese and Wine Farewell Func-
tion, Civic Centre
'NOTE Weather permitting, this will be an open air function Comfortable yet
warm clothing is therefore indicated Also note that buses will depart
for Bien Donnd directly after the technical sessions and that Tour L 1
will conclude at Bien Donn6 Suitable clothing arrangements should
therefore be made on leaving the hotels in the morning
POST CONFERENCE SEMINARS
The following post-conference seminars will be held at the Conference Centre
of the Council for Scientific and Industnal Research, Pretoria, on 5-6 Apnl
1982.
S 1 Modern trends in sludge management
S 2 Water virology
S 3 Mine water pollution
S 4 Phosphate removal in biological treatment processes
Copies of the full programmes are available on request at the Registration
Desk
-297-
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TIMETABLE FOR BUSES
NOTES 1 Group A hotels in Sea Point Area: Ambassador, President, Ar-
thur's Seat, Ritz Plaza
2 Group B hotels in Upper City Area: De Waal, Mount Nelson
3 Group C hotels In Central City Area: Town House. Inn-on-the-
Square
4 Group 0 hotels in Conference Centre Area: Capetonian, Tul-
bagh Square, Heerengracht
5 Bus transport will NOT be provided during the day-time for Group
C and 0 hotels which are within comfortable walking distance
from the Civic Centre.
6 The bus service will be provided at no cost to registered delegates
and registered accompanying persons
7 Although only one time of departure from hotels is given in each
instance, this time will not be precise as any specific bus will
mostly serve more than one hotel However, please regard the
given times as the latest time of departure from your hotel in order
to ensure the smooth operation of the bus sen/ice
HOTELS SERVED
Sunday 28 March
09h00 Depart from hotels for tours
PCT 4 (Cape Point) and PCT
5 (Hermanus)
09h30 Depart from Civic Centre on
GROUP A&B
Tours PCT 4 and PCT 5
(expected time of return to
hotels 16h30)
14h30 Depart from hotels for Civic
Centre for tour PCT 3
(Orientation)
15h00 Depart from Civic Centre on
Tour PCT 3 (expected time of
return to hotels 16h30)
16h30 Depart from Civic Centre for
hotels
18h30 Depart from hotels for Meet
and Greet function at
Heerengracht Hotel
20h30 Depart from Heerengracht
Hotel to vanous hotels
GROUP A&B
GROUP A&B
GROUP A&B
GROUP A, B & C
-298-
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HOTELS SERVED
Monday 29 March
08h00 Depart from hotels for
registration at Civic Centre
and Opening Ceremony at
Nico Malan Theatre
11 hOO Accompanying persons
depart from Civic Centre for
lunch at Bloubergstrand
(expected time of return to
hotels 15h00)
17h40 Depart from Civic Centre after
Technical sessions, for hotels
18h45 Depart from hotels for Civic
Reception, Civic Centre
(concourse)
20h30 Depart from Civic Centre for
hotels
GROUP A & B
GROUP A & B
GROUP A & B
GROUP A, B & C
Tuesday 30 March
07h45
09h00
09h30
16h40*
•NOTE:
21h00-
23h00
Depart from hotels for
technical sessions at Civic
Centre
Depart from hotels for Tour
L 1 (Wine route)
Depart from Civic Centre on
Tour L 1 This tour concludes
at Bien Donnd (expected time
17h30) where group will be
joined by delegates for
braaivlets (barbecue)
Depart from Civic Centre for
braaivleis (barbecue) at Bien
Donnd (expected arrival
18h00)
Accompanying persons not
participating in Tour L 1. must
take this bus to attend the
braaivleis (barbecue) at Bien
Donnd
Buses return to hotels as they
are filled up by passengers
(travelling time about 1 hour)
GROUP A & B
GROUP A & B
(Hotel courtesy cars)
All Conference hotels
-299-
-------
Wednesday 31 March
OfihOO Depart from hotels for
technical tours T1-T6
Delegates will be returned to
their hotels after the technical
tours
08h30 Depart from Civic Centre on
technical tours T1-T6
09h00 Depart from hotels for Tour
L 2 (Mountain Passes)
09h30 Depart from Civic Centre on
Tour L 2 (expected time of
return to hotels 17h30)
Thursday 1 April
08h00 Depart from hotels for
technical sessions at Civic
Centre
09h00 Depart from hotels for Tour
L 3 (Kirstenbosch)
09h30 Depart from Civic Centre on
Tour L 3 (expected time ol
return to hotels 13h00)
09h00 Depart from Civic Centre for
specially arranged technical
visits, and returning at
approximately 13h00
17h40 Depart from Civic Centre for
hotels
19h00 Depart from hotels for
Conference Banquet at Good
Hope Centre, commencing
19h30
23h00 Depart from Good Hope
Centre lor hotels
(expected travelling time 30
minutes)
Friday 2 April
08h00 Depart from hotels for
technical sessions at Civic
Centre
09h00 Depart from hotels for Tour
L 4 (Cape Point)
HOTELS SERVED
GROUP A & B
GROUP A & B
(Hotel courtesy cars)
GROUP A&B
GROUP A&B
(Hotel courtesy cars)
GROUP A&B
GROUP A. B.C & D
GROUP A. B. C & D
GROUP A&B
GROUP A&B
(Hotel courtesy cars)
-300-
-------
HOTELS SERVED
Depart from Civic Centre on
Tour L 4 (expected time of
return to hotels 17h00)
Accompanying persons
participating in Tour L 4 and
who wish to attend the
cheese and wine farewell
function (I7h35-19h00) can
alight at the Civic Centre
Depart from Civic Centre after GROUP A & B
cheese and wtne function
GENERAL INFORMATION
Members of the Conference Organizing Committee and of the Cape Town Lo-
cal Committee will be wearing name tags with green and red nbbons respec-
tively They will be happy to assist delegates whenever possible or refer them
to those who can assist them
REGISTRATION
Registration will take place on the mezzanine level, Civic Centre at the follow-
ing times
Sunday 28 March 16h00-18h30
Monday 29 March 07h30-08h30
Latecomers can register at any time after the Opening Ceremony dunng the
official conference hours
DAILY LUNCHES AND REFRESHMENTS
Tea/Coffee will be provided free of charge dunng the penods indicated on the
technical programme as well as in the mornings before commencement of the
technical sessions
Lunches R5.00 per meal
Please note that restaurants in the immediate vicinity of the Civic Centre are
usually crowded dunng the lunch hour Arrangements have therefore been
made for lunches to be served to delegates at the Civic Centre concourse tea-
room at a cost of R5.00 per head
Tickets for lunches will be available at the registration desk and MUST be pur-
chased at least one day in advance to facilitate catenng arrangements
For the technical visits on Wednesday 31 March, boxed lunches will be pro-
vided at no charge
09h30"
• NOTE:
19h00
-301-
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CAR RENTAL
Car rental services can be provided by AVIS who will have a desk in the regis-
tration area
FIRST AID
The Red Cross will be on hand in the registration area, to provide first aid if
this should be required
PHILATELIC FIRST DAY COVERS
A special first day cover featuring the 11th IAWPR Conference has been
pnnted and can be bought for 60c in the registration area
INTERPRETATION
Simultaneous interpretation services in English. French and German will be
provided in Halls A, B and C during all the technical sessions
BANKING
Banks at which travellers cheques can be exchanged etc are situated close to
the Civic Centre
ACCOMMODATION AND TOUR ENQUIRIES
The South Afncan Transport Services. Publicity and Travel Department will
have a desk in the registration area to deal with accommodation and tour en-
quines
AIR RESERVATIONS
Delegates can obtain assistance with their air reservations at the South Afn-
can Airways desk in the registration area
ORESS
Formal dress is not required dunng the Conference or for the evening func-
tions Lounge (business) suits will probably be worn by gentlemen attending
the conference banquet
POSTAL FACILITIES
Post boxes and stamp machines are available in the concourse of the Civic
Centre
VENUE FOR SPECIAL MEETINGS
A venue is available at the Civic Centre for groups who wish to arrange
special meetings (maximum 30 people) This venue must be reserved before-
hand at the registration desk
NOTICE BOARD
A notice board will be available in the registration area for displaying special
messages
-302-
-------
ADDRESS FOR TELEX MESSAGES
The Cape Regional Laboratory of the National Institute for Water Research
will receive and relay telex messages to delegates The telex address is. 57-
27819SA.
TELEPHONES
Public telephone booths are available in the Civic Centre concourse.
The telephone numbers for incoming calls are.
Cape Town (021) 21-1392 and 21-1598
ACKNOWLEDGEMENTS
The following organizations have granted generous sponsorships for this con-
ference Their assistance is gratefully acknowledged by the Conference Orga-
nizing Committee and by the South Afncan National Committee of the IAWPR
AECI Limited
Anglo American Corporation of S A Limited
Chamber of Mines of South Africa
City Council of Cape Town
ISCOR Limited
Kllpfontein Organic Products
Mondi Paper Company Limited
Ohlsson's Cape Breweries
Oude Meester Group Limited
SAPPI Limited
SASOL Limited
South African Council (or Scientific and Industrial Research
Stellenbosch Farmers' Winery
Water Research Commission
Appreciation is also due to
Fruit and Fruit Technology Research Institute for arranging and catenng
for the braaivleis at Bien Donn6
Geustyn, Forsyth & Joubert for prepanng and publishing the booklet provid-
ing technical details of the installations covered by the technical visits T1-T6
Ninham Shand and Partners Inc. for providing the venue and other services
for meetings of the Conference Organizing Committee and the Cape Town Lo-
cal Committee, and (or prepanng and publishing the brochure for the Orienta-
tion Tour of Cape Town (PCT 3)
The Red Cross for being on duty at the Civic Centre dunng the conference, at
no cost
The following hosts for technical visits dunng and after the conference
AECI Limited
Bellvllle Town Council
Cape Town City Council
East Rand Gold and Uranium Company Limited
-303-
-------
East Rand Proprietary Mines Limited
Electricity Supply Commission
Institute of Sea Fisheries
Milnerton Town Council
National Institute (or Water Research
Paarl Town Council
SAPPI Limited
SASOLII
University of Cape Town
The following organizations which contributed towards the social programme
associated with the IAWPR Governing Board meetings pnor to the Confer-
ence
Cape Town City Council
Constantia Control Board
Klrsten Farms, Paarl
KWV Limited
Paarl Town Council
Simonsvlei Winery
OFFICE BEARERS
CONFERENCE PRESIDENT: Or G J Stander
ORGANIZING COMMITTEE:
Mr C Visser
Mrs M Reeler
Mr W R Ross
Prof L S Smith
Or G J Stander
Mr A E Thorne
Mr Minnaar Smit
Mr D W Osborn
Mr J Panter
Mr H Blersch
Prof A D Carr
Or G G C1H16
Mr P Coombs
Mr S T Foune
Mr F Gouws
Mr E J Hall
Mr K R McCusker
Mr P E Odendaal
Chairman. Organizing Committee
Chairman. Cape Town Local Committee
Member/University of Cape Town
Chairman, S A National Committee
Secretary, S A National Committee
Secretary, Cape Town Local Committee
South Afncan Airways
IAWPR Governing Board Member
Secretary, Organizing Committee
Member/City Health Department, Johannesburg
South Afncan Transport Services
Symposium Secretanat, CSIR
Vice-Chairman, Cape Town Local Committee
South Afncan Transport Sen/ices
Member/Department of Health
Conference President
Member/City Engineer's Department,
Cape Town
South African Transport Services
IAWPR EXECUTIVE
President
Past President
Prof R S Engelbrecht, United States ot Amenca
Mr B Hawerman, Sweden
-304-
-------
Vice-Presidents
Conference President
Chairman, Finance
Committee
Executive Editor
Secretary-T reasurer
Prof P Harremoes. Denmark
Prof E Kuntze. Federal Republic of Germany
Dr G J Stander, Republic of South Africa
Mr E J Walder. Australia
Or S H Jenkins. United Kingdom
Mr Antony Milburn, United Kingdom
CAPE TOWN LOCAL ORGANIZING COMMITTEE
Mr H C Blersch (Chairman)
Mr H G J Beekman
Prof A D Carr
Mr J Clarke
Mr S T Fourie
Mr E P Gouws
Mr P J Heydenrych
Mr G E Hoppe
Mr J Krige
Mr B D Leslie
Mr W M Malan
Dr R H Marks
Mr W R Ross
Prof L S Smith
Mr A E Thome
Ninham Shand and Partners Inc
City Engineer s Department, Cape Town
University of Cape Town
Divisional Council of the Cape
National Institute of Water Research
Liebenberg and Stander
Hill, Kaplan. Scott and Partners
Hawkins, Hawkins and Osborn
Geustyn, Forsyth and Joubert
Ninham Shand and Partners Inc
University of Stellenbosch
R H Marks and Associates
National Institute of Water Research
Department of Health
City Engineer s Department, Cape Town
L1DIES COMMITTEE
Mrs
T
Blersch
Mrs
H
Clarke
Mrs
D
Leslie
Mrs
S
Ross
-305-
-------
APPENDIX II
UNITED STATES OF AMERICA NATIONAL COMMITTEE
For reprewntatlon of the United States to the
INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH
chairman
0 fl F NCD C. I'UHLANU (A i E.f I
SChOJL 0* CIVU INOINtfHING
iNitnvft u* rerHNiuoo*
AllAWTA, 6tn««rA IO>)f
|«9«l «f<
StCRC TAflV-TRl ASliRlR
MR flICHAftO A. CONWAY tA S C.T.I
•cse«*ci« c oevctopntMT
UNIOM CASeiO? COfi^UNAI ION
P. O 00*
ftOUlH CHAKLfSTON, «Btr *l«aiNM »•
(»o«i r«r-«oi«
January 29, 7982
TO:
FROM: F. G. Pohland, Chairman, USANC /
-------
Memorandum
Page 2
January 29, 1982
of a research nature outside of the technical or poster sessions of the Conference.
Shortly after the Conference, each contributor will submit a concise (typically
6 to 10 typed pages) report covering the pertinent developments at his/her
assigned session and other observations made at the Conference. If you are
selected to contribute to the report, more specific Information on the Intended
nature of the overall report and on individual report requirements will be for-
warded to you before the Conference.
Contributors to the report will be reimbursed for some of their expenses
and services. It should be pointed out that the purpose of the EPA grant to USANC
1s to prepare the report outlined above; it 1s not a travel grant. In fact,
reimbursement for international travel, I.e., that portion of your travel to Cape
Town and return to U.S., will not be allowed. However, contributors will be re-
imbursed for a portion of their services. The amount of reimbursement will de-
pend on the number of contributors and the funds available but should be adequate
to cover a good portion of the expenses associated with attending the Conference.
Please complete and return the enclosed form, Indicating your Interest
in contributing to the proposed report and the technical session you would Hke
to be assigned. In the interest of objectivity, please do not select sessions 1n
which you are a participant. A copy of the Cape Town Conference program 1s
attached.
This memorandum is being sent to only one author per paper. In the case
of multiple authorship, this mailing is being forwarded to the author who I
presume will be making the presentation at Cape Town or for whom I have an address.
If I have misdirected the memorandum, please forward it and the attached question-
naire to whomever will actually be making the presentation at Cape Town. It 1s
necessary, because of limited funds, to solicit only one author per paper as a
potential contributor to the report.
If I do not hear from you by February 15, 1982, I shall assume that you
are not interested in participating 1n the preparation of the report. If you have
any question, please telephone me at (404) 894-2265.
hb
Attachments
-307-
-------
QUESTIONNAIRE
Concerning Participation in Preparation of
Proposed USANC Report for EPA on
DEVELOPMENTS AT ELEVENTH INTERNATIONAL CONFERENCE
ON WATER POLLUTION RESEARCH
Cape Town, South Africa
March 29-April 2, 1982
1. I shall be a participant 1n the IAWPR Conference 1n Cape Town in the
following capacity(ies):
Presenting Paper or Poster Number .
Invited Discusser of Paper Number .
Chairman of Session on at
Hall date time
Recorder of Session on at
Hall date time
2. I (do) (do not) wish to participate in developing the proposed report
to EPA.
3. If you wish to participate in developing the proposed report to EPA,
complete the next page relative to the session you are interested in
covering.
4. I (would) (would not) like to receive a copy of the USANC report
covering the 1980 Toronto IAWPR Conference (supply limited).
5. Name
Mailing Address
Phone
Date
Signature
PLEASE COMPLETE AND MAIL SO AS TO REACH:
F. G. Pohland
School of Civil Engineering
Georgia Institute of Technology
Atlanta, Georgia 30332
BY FEBRUARY 15, 1982
-308-
-------
USANC
Name
6. Indicate the sessions of most interest to you by priority, I.e., 1, 2, and 3.
Priority
MONDAY, 29 MARCH
~Hall A, 11:45am
**Hall B, 11:45 am
***Hall C, 11:45 am
*Hall A, 2:00 pm
**Hall B, 2:00 pm
***Hal1 C, 2:00 pm
Session
12:30 pm (Paper 1)
12:30 pm (Paper 2)
12:30 pm (Paper 3)
5:30 pm (Papers Nos. 4, 7, 10, 13)
5:30 pm (Papers Nos. 5, 8, 11, 14)
5:30 pm (Papers Nos. 6, 9, 12, 15)
TUESDAY,
30 MARCH
Hall A,
9:00 am
_
12:30
pm
(Papers Nos.
Hall B,
9:00 am
-
12:30
pm
(Papers Nos.
Hall C,
9:00 am
-
12:30
pm
(Theme 1)
Hall A,
2:00 pm
_
5:30
pm
(Papers Nos.
Hall B,
2:00 pm
-
5:30
pm
(Papers Nos.
Hall C,
2:00 pm
-
5:30
pm
(Theme 2)
THURSDAY,
1 APRIL
Hall A,
9:00 am
_
12:30
pm
(Papers Nos.
Hall B,
9:00 am
-
12:30
pm
(Papers Nos.
Hall C,
9:00 am
-
12:30
pm
(Theme 3)
Hall A,
2:00 pm
_
5:30
pm
(Papers Nos.
Hall B,
2:00 pm
-
5:30
pm
(Papers Nos.
Hall C,
2:00 pm
-
5:30
pm
(Theme 4)
FRIDAY, 2
APRIL
Hall A,
9:00 am
_
12:30
pm
(Papers Nos.
Hall B,
9:00 am
-
12:30
pm
(Papers Nos.
Hall C,
9:00 am
-
12:30
pm
(Theme 5)
Hall A,
2:00 am
_
5:30
pm
(Papers Nos.
Hall B,
2:00 am
-
5:30
pm
(Papers Nos.
Hall C,
2:00 am
-
5:30
pm
(Theme 6)
16, 18, 20, 22)
17, 19, 21, 23)
40, 42, 44, 46)
41, 43, 45, 47)
51 , 53, 55)
*Same person should review both sessions.
**Same person should review both sessions.
***Same person should review both sessions.
-309-
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APPENDIX III
ASSIGNMENTS
Participants in USANC Project
TECHNICAL PRESENTATIONS
DATE/
TIME
Hall A
Hall B
Hall C
March 29
11:45- 5:35
March 30
8:30-12:05
12:35- 4:35
April 1
9:00-12:35
1:15- 5:35
April 2
9:00-12:35
2:00- 5:35
B. H. Olson
Papers 1,4,7,10,13
E. J. Massaro
Papers 16,18,20,22
P. V. Scarpino
Papers 24,26,28,30
A. J. Englande
Papers 32,34,36,38
G. H. Rohlich
Papers 40,42,44,46
R. D. Neufeld
Papers 48,50,52,54
J. P. Gould
Papers 56,58,60,62
W. C. Boyle
Papers 2,5,8,11,14
E. S. K. Chian
Papers 17,19,21,23
D. Roy
Papers 25,27,29,31
D. Jenkins
Papers 33,35,37,39
F. B. DeWalle
Papers 4,43,45,47
A. H. Molof
Papers 49,51,53,55
P. L. Bishop
Papers 57,59,61,63
J. B. Andelman
Papers 3,6,9,12,15
P. J. Roberts
Theme 1 Workshop
L. H. Keith
Theme 2 Workshop
C. Guarino
Theme 3 Workshop
A. Netzer
Theme 4 Workshop
K. Kawata
Theme 5 Workshop
R. D. Heaton
Theme 6 Workshop
POSTER PRESENTATIONS
Name
G. Bel fort
B. A. Bell
R. A. Canham
T. H. Goodgame
K. D. Lindstedt
H. C. Pruel
C. W. Randall
Poster Presentations
54, Sll, SI2, S22, S27
55, S6, S21, S26, S31
S2, SI7, S23, S32, S33, S34
S7, S8, S9, S10, S28, S29
S35, S36, S37, S38, S39, S40
S13, S16, SI9, S20, S24, S30
SI, S3, SI 4, SI 5, SI 8, S25
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EDITORS
Executive Editors (Coordinating Subcommittee)
F. G. Pohland
R. A. Conway
R. S. Engelbrecht
D. Stephan
Editors
E. R. Baumann
R. I. Dick
F. M. Saunders
0. J. Sproul
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APPENDIX IV
UNITED STATES OF AMERICA NATIONAL COMMITTEE
For representation of the United States to the
INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH
QfttnWN
OR. RICHARD S. ENttlBRECHT (W.P.C.F.)
OEPARUCNT OF CIVIL ENGIKEERING
UNIVERSITY OP ILLINOIS AT URBMtt-OiUCUIW
tnwA, iLLtrois tisoi
(tin J33-3S22
VICE-CWlfMPM
OR. FHEO G. POHUW) (A.E.E.P.)
SOCO. OP CIVIL BttllCERING
GEORGIA INSTITUTE OF TEOMUCV
ATLANTA, GECRGIA 30112
(404) 094-224B
SECSETWW-TREASUHEH
MR. RICHARD A. COMIAY lA.SC.f.l
ICSEMKH I KWLCPMENT DCPAnT>B4T
UNION CAPBJCg CORPORATION
P. C. BOX 8361
SOUTH CHARLESTON. «EST VIRGINIA M30J
13041 74T-40I*
MEMORANDUM
DATE: February 28, 1982
TO:
FROM: F. G. Pohland, Chairman
SUBJECT: Assignments for Development of USANC Report on Cape Town Conference
In anticipation that USANC's proposal for developing the Cape Town
Conference report will be funded, it is necessary to move ahead in implementing
the project.
The Coordinating Subcommittee for preparing USANC's analysis of develop-
ments at the IAWPR Conference in Cape Town has assigned sessions to be covered by
participants in the project. Your assignment is to prepare a penetrating analysis
of developments at the following:
Formal Sessions:
Date
Hall
Time
Poster Presentations:
The Subcommittee regrets that the expressed preferences of all participants for
particular sessions could not be accommodated.
SPONSORING ORGANIZATIONS
ASSOCIATION OP ENVIRONMENTAL - 31 2 - AMERICAN CHEMICAL SOCIETY
AMERICAN INSTITUTE OF CHEMICAL ENQINEERS AMERICAN SOCIETY OF CIVIL ENGINEERS WATER POLLUTION CONTROL Ft01 NATION
11TH INTERNATIONAL CONFERENCE ON WATER POLLUTION RESEARCH, CAPE TOWN, SA, 29 MARCH-2 APRIL 1982
-------
Assignments for Development of
USANC Report on Cape Town Conference
Page 2
From: F. G. Pohland
It is essential that you contact one of the members of the USANC
Coordinating Subcommittee soon after you arrive in Cape Town. The purpose is
to verify your presence and to learn of any necessary changes in assignments.
The members of the Subcommittee are:
Frederick G. Pohland
Richard S. Engelbrecht
David G. Stephan
Richard A. Conway
E. Robert Baumann
Guidelines for preparation of individual reports are enclosed. Inas-
much as each individual's report will appear in the overall project report, it
is essential that the guidelines be followed closely. Note particularly the
deadline (July 1, 1982) for submission of reports; to achieve maximum value,
the report must be submitted soon after the Conference.
It is emphasized that each individual's report is to be an inter-
pretive analysis of developments at the Conference. Proceedings, including
discussions, will be published by IAWPR, and these will serve as an objective
record of the technical details presented at the Conference. Your report need
not, therefore, include the detailed information that will be contained in the
Conference Proceedings. What is needed for the USANC report is an assessment
of the significance of the presentations and information related to the
presentations which will not be found in the Conference Proceedings. Such
information might, for example, come from personal discussions with authors or
contributors to discussions or poster presentations. For those of you who
have participated in the preparation of our prior reports, please note that the
outline for individual reports has been modified.
In addition to coverage of the assigned session, participants are spe-
cifically requested to report pertinent developments aj: the Conference which
do not occur during the formal presentations (see Section VI of the out!ine for
individual reports). Enclosed is the entire section of the report on the
1980 Conference which concerned developments outside of the technical or poster
sessions. Please look it over to gain an idea of the type of information desired.
It is felt that this section is unusually important and provides a unique flavor
to this series of USANC reports. It is hoped that this section of the report on
the Cape Town Conference can be expanded over that for our previous efforts.
Remember, information presented during the poster sessions probably will not be
published intact and therefore requires special attention and coverage.
Information on compensation for services and expenses is included in
the guidelines. Experience with previous reports has required implementation
of rigid financial motivations for submission of reports prior to the deadline;
please note the deadline for submission of reports. You should also be aware
that the Internal Revenue Service has regulations on deducting personal expenses
for attending foreign conferences; this information can be obtained from the IRS.
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GUIDELINES
for
PREPARATION OF INDIVIDUAL REPORTS
on
DEVELOPMENTS AT THE ELEVENTH INTERNATIONAL CONFERENCE
ON WATER POLLUTION RESEARCH
CAPE TOWN, SOUTH AFRICA
March 29 - April 2, 1982
Emphasis of Report
USANC's report on developments at the IAWPR Conference in Cape
Town is not intended to be simply a record of the Conference. Instead,
an interpretive analysis of significant developments at the Conference
is required. This penetrating assessment is to be developed not only by
critical analysis of papers and formal and informal discussions at the
technical and poster sessions, but also by inclusion of insights gained
through more informal contacts with Conference participants.
The positive aspects of Conference developments should be
emphasized (what did you learn that is important to United States water
pollution research activities?). Don't dwell on criticism of papers
which you feel to be inferior, and don't give much space to papers which
are not pertinent to problems in the Unites States. Don't include in-
formation of limited significance such as how many people attended a
session, how well the session chairman performed, etc.
Pi stribution
The report will be distributed at least within EPA, to USANC
Sponsoring Organizations and USANC committee members, and to participants
in the report development. The report also will be made available to the
public through the National Technical Information Service; its avail-
ability will be announced through notices in publications of USANC's
Sponsoring Organizations.
Length
Individual reports on sessions are to be as short or long as
necessary to adequately describe pertinent developments. It is not
necessary to give equal attention to each paper or poster. Space in the
report should be allocated on the basis of relevance to U. S. water
pollution control problems and water pollution research activities. It
is anticipated that the average length of individual reports will be a
tightly written 6 to 10 double-spaced pages, but don't unnecessarily
expand or condense a concise, penetrating report merely to achieve that
length.
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-2-
Format
The organization and content of the individual reports is to be
as indicated in the outline included as Attachment I. Note that the last
section of the report provides an opportunity to record observations which
do not relate to your assignment and that it should begin on a separate
sheet of paper. These contributions from all participants will be combined.
Metric units should be used, and the editorial standards for
Water Research {included as Attachment II) should be observed.
It is hoped that arrangements can be made to record the English
translation of each technical session; thus, it may be possible to provide
cassette tapes of assigned sessions following the Conference.
Submission
Individual reports are to be submitted in double-spaced typed
finished form. Four copies of the report are to be postmarked no later
than July 1, 1982 and addressed to:
F. G. Pohland
School of Civil Engineering
Georgia Institute of Technology
Atlanta, GA 30332
Prompt submission of reports is essential. As indicated in the
following section, reimbursement for late reports will be at a reduced
level and no reimbursement will be made for reports postmarked after July
15, 1982.
Compensation
Compensation will require a submitted statement for services and
expenses and, as stated above, reimbursement will be contingent upon post-
marking of an acceptable report prior to the deadline. No reimbursement
for international travel can be allowed. A maximum level of reimbursement
will be established based on available funds, cost sharing requirements,
and demands on available funds. Furthermore, because the maximum allowable
level of compensation will depend on the magnitude of the total requests
for compensation, no payments can be made until all reports are approved
(one late individual could hold up all payments). Requests for reimburse-
ment are to be sent to the USANC Secretary-Treasurer, Richard A. Conway,
Union Carbide Corporation, P. 0. Box 8361 (770-342), South Charleston, WV
25303. Use the expense voucher included as Attachment III for this purpose.
Reimbursement for acceptable reports postmarked after July 1,
1982, will be reduced by 50 percent. No reimbursement will be made for
reports postmarked after July 15, 1982.
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-3-
Coordinatinq Subcommittee
Development of these guidelines, review and acceptance of
individual reports and preparation of the final EPA report is being
coordinated by a USA National Committee Coordinating Subcommittee
consisting of:
Frederick G. Pohland
School of Civil Engineering
Georgia Institute of Technology
Atlanta, GA 30332
Phone: (404) 894-2265
Richard S. Engelbrecht
Department of Civil Engineering
University of Illinois
Urbana, IL 61801
Phone: (217) 332-3822
David G. Stephan
Industrial Environmental Research Laboratory
Environmental Protection Agency
Cincinnati, OH 45268
Phone: (513) 684-7418
Richard A. Conway
Union Carbide Corporation
P. 0. Box 8361 (770-341)
South Charleston, WV 25303
Phone: (304) 747-4016
E. Robert Baumann
496 Engineering Annex
Iowa State University
Ames, IA 50010
Phone: (515) 294-4975
Additional information concerning this USANC activity may be obtained from
any of the Subcommittee members.
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ATTACHMENT I
OUTLINE FOR INDIVIDUAL REPORTS ON
DEVELOPMENTS AT CAPE TOWN IAWPR CONFERENCE
*1. SESSION
*A. Day, Hall, Time
*B. Theme of Session (a few words describing the major
orientation of papers - e.g., "Marine Disposal"
or "Sludge Thickening and Dewatering")
*11. REVIEWER
*A. Name
*B. Position and Affiliation
*111. DESCRIPTION OF SESSION PAPERS OR POSTERS
(Paper-by-pa per summary, starting with identification,
author's or reviewer's abstract, followed by highlights
of the formal presentations, prepared discussions and
floor discussions. For poster papers, use same format
but include as a separate report.)
*IV. CRITIQUE OF SESSION
(Observations and commentary regarding the session and
its papers including insights developed outside of the
meeting room, possible sources of additional information,
and critical review of the papers and the session, in-
dicating matters such as how the research reports were
received, their originality and quality, etc.)
*V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH
ACTIVITIES
(How might the reported results be applied to solve U.S.
water pollution problems? What research pertinent to
U.S. needs is suggested by the reported research?)
*VI. INFORMATION AND OBSERVATIONS FROM THE CONFERENCE RELEVANT TO
U.S. WATER POLLUTION RESEARCH BUT UNRELATED TO ASSIGNED SESSION
(For example, information on water pollution-related
developments which was not presented at any of the formal
sessions at the Conference, information on emerging
problems or on research-in-progress which may be of
particular importance.) See "Illustrative Contributions
from Assigned Session" attached.
NOTE: Section VI will be separated from the remainder of
the individual reports - begin on a separate sheet
which includes your name.
*These headings are to be contained in each report.
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ATTACHMENT II
SCRIPT REQUIREMENTS
). An original typed copy in double spacing and two copies should be submitted. The text must be ready for
printing, and any substantial changes in proof other than typographical errors may be charged to the authors.
2. HalMone illustrations should be restricted to the minimum necessary and the photographs may be on
glossy not matte paper, enlarged sufficiently to permit their clear reproduction in half-tone. These must ac-
company the manuscript, preferably mounted on separate sheets. If words or numbers appear on photographs
two copies are requested, one clearly primed and the other without inscription. If line drawings are already uell
drawn, it may be possible to reproduce them direct from the original, but in this case it is essential that the
original drawings or good photo-prints should be provided. It is not possible to reproduce from "djclinc"'
prints or from prints with ucak lines, and illustrations for reproduction should normally be about luicc the
final size required. All illustrations should be provided with descriptive legends and the illustrations should
accompany manuscripts separately, with legends typed on a separate sheet. The manuscript and diagrams will
be discarded one month after publication unless the publisher is requested to return original material to the
author,
3. In the interests of economy and in order to avoid the introduction of errors, tables will be reproduced by
photo-ofTsci means directly from the authors' manuscripts.
(a) Look at current Tables m the Journal, and arrange >our spatial layout of the Table to conform.
(b) Type should be clear and even, either on an electric typewriter with a carbon ribbon, or LETRASET.
(c) Tables, headings and legends should be typed on a separate sheet.
(d) Insert rules.
(e) Words normally italicized should be typed in italics or underlined.
4. References to published literature should be quoted in the text as follows: Smith (1930)—the date of publica-
tion, in parentheses, following the author's name. References should be listed together at the end of each paper
and not gi\cn as footnotes. They should be arranged m alphabetical order (first author 's surname) v, tth the name
of the periodical abbreviated in the style of the W'orU List of Scientific Periodicals (4th edn, Buttcrworths,
London, 1963-1965, 3 vols) and appear as follows:
Fermi G. and Marshall L. (1947) On the interaction between neutrons and electrons. Pfiyi. Rev.72,1139-1146.
Thring M. W. (19J7) Air Pollution, p. 132. Dutterworths, London.
It is particularly requested that (a) authors' initials (b) title of the paper and (c) the volume or part numbers
' and page numbers both beginning and end are given in every case.
5. Papers should be without unnecessary historical introduction.
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ATTACHMENT HI
USANC REIMBURSEMENT REQUEST
Expenses incurred relating to preparation of interpretive analysis of the 11th
Biennial International Water Pollution Control Conference, Cape Town, South
Africa, March 29 - April 2, 1982. The first column should show the total cost
of developing the report including your services and expenses - the information
is needed for cost sharing calculations. Show in the second column the actual
reimbursement requested. Leave the third column blank.
ITEM
(1)
AMOUNT
(2)
REIMBURSEMENT
REQUESTED
(3)
REIMBURSEMENT
APPROVED
Professional Services (collection/
assimilation/analysis of infor-
mation, report preparation, etc.)
days @ $ per day*
Conference Registration (-$182)**
Subsistence during Conference**
(Hotel and meals)
days @ $57 per day
Travel Costs**
Air:
- Within U.S.
- International***
Personal Auto
- Within U.S.
miles @ 20t per mile
Miscellaneous (Please itemize)
- Limousine, cab fare
(no rental cars, no secretarial)
*Indicate days claimed and consulting rate per day (USANC will set a maximum).
**Attach Conference registration, hotel and air travel receipts.
~¦"¦"International Travel is considered to be from U.S. city of embarkation to
Cape Town and return to the U.S.; include amount in column (1) only.
Send this voucher to:
Signature
Richard A. Conway
Research and Development
Union Carbide Corporation Social Security
P. 0. Box 8361 (770-342)
South Charleston, WV 25303
Date of Submission
FOR COORDINATING SUBCOMMITTEE USE ONLY:
Date and Amount Paid
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