DEVELOPMENTS AT EIGHTH INTERNATIONAL
CONFERENCE ON WATER POLLUTION RESEARCH
Sydney, Australia
October 17-22, 1976
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
February 1977
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DEVELOPMENTS AT EIGHTH INTERNATIONAL CONFERENCE
ON WATER POLLUTION RESEARCH
Sydney, Australia
October 17-22, 1976
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
February 1977
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UNITED STATES OF AMERICA NATIONAL COMMITTEE
For representation of the United States to the
INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH
O\ airman
OR RICHARD I DICKIAtEPl
Department ol Crvil Engineering
University ol Delaware
Mewark Delaware 19711
(3021 7382431
Vice cnairrnin
OR DAVIDG 5TEPHAN (A I Ch E I
Office of Research and Development
Environmental Protection Agency
Washington DC 20460
12021 755 CM74
SKrniry Trealurtr
OR RICHARDS ENGELBRECHT IWPCF I
Department of Civil Engineering
University of Illinois al Urban* Champaign
Urbmia Illinois 61801
121713333822
March 21, 1977
Mr. William T. Sayers, Chief
Water Quality Staff
Office of Air, Land, and Water Use
Office of Research & Development
U. S. Environmental Protection Agency
Washington, D. C. 20460
Dear Mr. Sayers:
This report on "Developments at the Eighth International Conference on
Water Pollution Research" is submitted in accordance with provisions of EPA
Grant No. R804288010 to the United States of America National Committee for
Representation of the United States to the International Association on
Water Pollution Research. The report contains an analysis of formal and
informal developments at the Conference which are of special relevance to
water pollution control activities in the United States.
Members of the U. S. A. National Committee feel confident that this
report on current water research activities throughout the world will be
useful to EPA's Office of Research & Development. Should questions arise
concerning specific details in the report, please feel free to contact the
Committee for clarification.
SPONSORING ORGANIZATIONS
ASSOCIATION OF ENVIRONMENTAL ENGINEERING PROFESSORS AMERICAN CHEMICAL SOCIETY
AMERICAN INSTITUTE OF CHEMICAL ENGINEERS AMERICAN SOCIETY OF CIVIL ENGINEERS
WATER POLLUTION CONTROL FEDERATION
October 17-22, 1977
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Mr. William T. Sayers
Page Two
March 21, 1977
rt has been a pleasure to have been associated with the Office
of Research & Development in this activity. We have, in particular,
appreciated the cooperation of you. Dr. Thomas A. Murphy, and Dr. Louis
G. Swaby.
Sincerely,
Richard I. Dick, Chairman
For USANC Coordinating Subcommittee:
Bernard B. Berger
Richard S. Engelbrecht
Richard I. Dick
David G. Stephan
ks
Enclosure
11
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CONTENTS
Letter of Transmittal i
Key to Reviews vi
Executive Summary xii
I. Introduction 1
II. Individual Reports 4
Sessions by Theme
a. Spray Irrigation with Wastewater 4
(Including Paper Nos. 1, 4, 7, 10)
Reviewer: Shaukat Farooq
b. General 12
(Including Paper Nos. 13, 16, 19)
Reviewer: Joseph F. Malina, Jr.
c. Lakes, Reservoirs and Surface Water Quality. . . 20
(Including Paper Nos. 2, 5, 8, 11)
Reviewer: Fladimir Novotny
d. Groundwater Pollution 32
(Including Paper Nos. 14, 17, 20)
Reviewer: T. E. Larson
e. Chlorination, Flocculation and Adsorption ... 36
(Including Paper Nos. 3, 6, 9, 12)
Reviewer: John P. Giesy, Jr.
f. Coastal Pollution 40
(Including Paper Nos. 15, 18, 21)
Reviewer: R. E. Speece
g. Dynamics of Biological Nitrification 45
(Including Paper Nos. 22, 25)
Reviewer: John Cairns, Jr.
h. General 47
(Including Paper Nos. 28, 31, 24)
Reviewer: James H. Reynolds
i. Workshop - Ultimate Disposal of Sludges, .... 56
Toxic Wastes and Strong Organic Liquors
Reviewer: Davis L. Ford
j. Sludge Thickening and Dewatering 61
(Including Paper Nos. 23, 26)
Reviewer: E. Robert Baumann
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k. Pyrolysis of Sewage Sludge and Refuse ..... 73
(Including Paper Nos, 29, 32, 35)
Reviewer: John Zoltek, Jr.
1. Sludge Thickening ............... 78
(Including Paper Nos, 24, 27)
Reviewer: Bart T. Lynam
m. Aeration Ponds ................. 84
(Including Paper Nos. 30, 33, 36)
Reviewer: Edward S. K. Chian
n. Advanced Waste Treatment and Physicochemical . . 88
Treatment of Wastewaters
(Including Paper Nos. 37, 40, 43, 46)
Reviewer: Walter J. Weber, Jr.
o. Stabilization Ponds ............... 104
(Including Paper Nos. 49, 52, 55)
Reviewer: R. Addis Lockwood
p. Sulfide Attack on Sewers ............ 110
(Including Paper Nos. 38, 41, 44, 47)
Reviewer: Ivan L. Bogert
q. Automation and Aerobic and Anaerobic ......
Digestion
(Including Paper Nos. 50, 53, 56)
Reviewer: W. Wesley Eckenfelder, Jr.
r. Industrial Wastewater Management ........ 123
(Including Paper Nos. 39, 42, 45, 48)
Reviewer: Carl E. Adams, Or.
s. Monitoring of Waste Discharges ......... 131
(Including Paper Nos. 51, 54, 57)
Reviewer: Howard Edde
t. Workshop - Water Resources Quality Management. . 137
Reviewer: Robert A. Canham
u. Toxicity of Industrial Wastes ......... 142
(Including Paper Nos. 58, 61)
Reviewer: Richard D. Pomeroy
v. Stream Oxygen Balance and Bioassays ...... 146
(Including Paper Nos. 64, 67, 70)
Reviewer: N. Bruce Hanes
iv
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w. Workshop - Land Treatment 151
Reviewer: J. C. Lance
x. Removal of Organics and Tertiary Wastewater. . . 156
Treatment
(Including Paper Nos. 59, 62)
Reviewer: E. Robert Baumann
y. Ion Exchange 168
(Including Paper Nos. 65, 68, 71)
Reviewer: Alan H. Molof
z. Fixed Film Biological Contactors 178
(Including Paper Nos. 60, 63)
Reviewer: Calvin P. C. Poon
aa. Uptake, Exchange Kinetics, Transport 184
(Including Paper Nos. 66, 69, 72)
Reviewer: John Cairns, Jr.
III. Overview of Pertinent Conference Developments 187
Developments at Formal Sessions 187
Developments Outside of Formal Sessions 190
Appendices
I. Formal Conference Program 193
II. Session Assignments 203
III. Preliminary Instructions 204
IV. Detailed Instructions 206
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Key to Reviews
Paper No. Title and Authors Page
1. Spray Irrigation with Wastewater: The Problem of. ... 4
Aerosolization and Dispersion of Enteric
Microorganisms. E. Katzenelson, B. Tel ten, and
H. I. Shuval.
2. Great Lakes Water Quality Agreement. J. P. Bruce. ... 20
and P. M. Higgins.
3. Comparative Evaluation of Commercial Polyelectro- ... 36
lytes for Flocculating Alum Precipitated Domestic
Wastewater. A. Benedek and J. L. Bancsi.
4. Virus Retention by Soil. K. V. Abdulla Koya 7
and M. Chaudhuri.
5. Localised Destratification of Large Reservoirs to. ... 20
Control Discharge Temperatures. F. L. Burns.
6. Treatment of Chlorinated Hydrocarbons Wastewater .... 36
by Activated Carbon Absorption with Steam
Regeneration. Y. Argaman and G. M. Sassu.
7. The Removal of Viruses by Slow Sand Filtration 7
S. F. B. Poynter and J. S. Slade.
8. A Multidimensional Analysis of the Results of the. ... 25
French 1971 Surface Water Quality Network Control
in the River Basin "Seine-Normandie." Y. LeFoll,
R. Pinoit and A. Lesouef.
9. A Fundamental Study of the Removal of Polynuclear. ... 36
Aromatic Hydrocarbons from Water During Chlori-
nation. R. Perry and R. M. Harrison.
10. Virus Removal in Activated Sludge Sewage Treatment ... 7
V. C. Rao, S. B. Lakhe, S. V. Waghmare and P. Dube.
11. Hydrodynamics of Bubble Plumes and Oxygen Absorption . . 25
in Stratified Impoundments. F. Rayyan and R. E. Speece.
12. Chromium Removal with Activated Carbon. J. K. Kim ... 36
and J. Zoltek, Jr.
13. Nitrogen, Phosphate and Virus Removal from Sewage ... 12
Water During Land Filtration. J. C. Lance and
C. P. Gerba.
vi
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Paper No. Page
14. Technical Requirements and Analysis Methods for .... 32
Evaluating the Environmental Consequences of
Groundwater Contamination. R. VI. Nelson.
15. Sedimentation of Dispersed Oil in Surface Waters .... 40
M. Thuer and W. Stumm.
16. Faecal Coliforms and Faecal Streptococci: A 12
Statistical Comparison using Data from England
and Papua New Guinea. R. Feachem, K. Khan and
E. Rosebergen.
17. Pilot Plant Investigation of the Evolution of 32
Various Pollutants During Artificial Recharge
of an Aquifer by a Basin. M. Rizet, J. Malleviale
and J-C. Cournarie.
18. The Application of a Two-layer Time-Dependent 40
Model to Pollution Assessment and Control in a
Short Stratified Estuary. R. M. Pitblado and
R. G. H. Prince.
19. The Effect of Ozone Bubbles on Disinfection 12
S. Farooq, R. S. Engelbrecht and E. S. K. Chian.
20. Hydrochemical Effects of Waste Percolation on 32
Groundwater in Basalt near Footscray, Victoria,
Australia. M. Riha.
21. Preliminary Design of Ocean Outfall at Sydney: 40
Protection of Bathing Waters. I. G. Wallis,
T. J. Pollock and M. W. Whyte.
22. Dynamic Nature of Nitrifying Biological Suspended. ... 45
Growth Systems. K. L. Murphy, P. M. Sutton and
B. E. Jank.
23. Continuous Gravity Thickening of Sludges. P. Kos ... 61
24. Dissolved-Air Flotation in Activated Sludge 78
J. Bratby and G. v. R. Marais.
25. Design of a Nitrifying Activated Sludge Process 45
with the Aid of Dynamic Simulation. W. Gujer.
26. Dewatering Properties of Lime Stabilized Sewage 69
Sludges. B. Paulsrud and A. S. Eikum.
27. Variability of Temperature and Other Process 81
Parameters - A Time Series Analysis Sludge Plant Data.
K-C. Lin and G. W. Heinke.
vi i
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Paper No^ Page
28. An Integrated Pollution Control System: Combined .... 47
Clarification of Wastewater and Incinerator Scrubber
Effluent and Utilization of Clarified Effluent for
Scrubbing of Stack Emissions. W. J. Weber, Jr.,
F. L. Snitz and M. Rebhun.
29. Studies on Pyrolysis Process of Sewage Sludge 73
T. Majima, K. Tadao, M. Naruse and M. Hiraoka.
30. Comprehensive Temperature Model for Aerated 84
Biological Systems. Y. Argaman and C. E. Adams, Or.
31. Design Approach for Effluent Variability Removal .... 47
in Wastewater Treatment Systems. V. Novotny.
32. Combined Disposal of Sewage Sludge and Solid Wastes. . . 73
by the Pyrolytic Process. N. Brovko, R. A. Lockwood,
R. R. Bowerman and K. Y. Chen.
33. The Efficacy of an Equalization Pond in a Water .... 84
Reclamation System. B. M. Van Vliet, H. N. S.
Wiechers and 0. 0. Hart.
34. The Integration of Wastewater Treatment with Water ... 47
Reclamation. L. R. J. VanVuuren, W. R. Ross and
J. Prinsloo.
35. Disposal of Sludge Using Solid Wastes as Fuel with ... 73
Resource Recovery and Creation of Gas End-Product
for Utility Use. I. L. Bogert and D. S. Greene.
36. Scale-up Methodology for Surface Aerated Reactors. ... 84
N. W. Schmidtke and I. Horvath.
37. Investigations into the Lime Precipitation of Raw ... 88
Municipal Wastewater. D. Jenkins and F. M. Lee.
38. Simulation of Design-Storms with Probable Distribu-. . . HO
tions in Time and Space for Storm Drainage Systems.
F. Sieker.
39. Fellmongery Waste Treatment - Comparison of Cost . . . ,123
and Degree of Treatment. H. Melcer and P. N. McFarlane.
40. Calcium Carbonate and Magnesium Hydroxide Solu- .... 88
bility Product Values for Heterogenous Systems.
H. N. S. Wiechers.
41. The Significance of Stormwater Runoff in an HO
Urbanizing Watershed. C. W. Randall, J. A. Garland,
T. 0. Grizzard and R. C. Hoehn.
viii
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Paper No. Page
42. Treatment Alternatives for Wastewaters from the • • • • 123
Tapioca Starch Industry. M. B. Pescod and
N. C. Thanh.
43. Advanced Wastewater Treatment by Chemical Pre- 88
cipitation with Lime and Ammonia Stripping in
Ponds. E. Idelovitch, T. Roth and M. Michail.
44. Prevention and Protection of Sewerage Systems no
Against Sulphide Attack with Reference to
Experience in Singapore. A. Nadarajah and
J. Richardson.
45. Process Design Investigations for Alaska Pulp 123
Mill Wastewater Treatment Facilities. H. Edde,
R. French, 0. Mason and T. Hosoi.
46. Improvement of Tertiary Filtration Efficiency by .... 88
Upgrading Biological Activity. G. H. Faup,
J. L. Bebin and J. C. Jacpuart.
47. The Forecasting of Sulphide Build-up Rates in no
Sewers. R. D. Pomeroy and J. D. Parkhurst.
48. Measurement and Treatment of Oil and Grease in 123
Petroleum and Petrochemical Industrial Wastewaters.
L. F. Tischler, R. L. Elton,III and D. L. Ford.
49. Recirculation Ponds - Pilot Plant and Field Studies. . . 104
G. Shelef, M. Ronen and M. Kremer.
50. Current Status of Research in Automation of Waste- ... 119
water Treatment in the United States. J. F. Roesler,
D. F. Bishop and I. J. Kugleman.
51. Pollution Control Regulations and Monitoring 131
Technology: A Review of Research and Development
from the Pulp and Paper Industry. D. V. Ellis.
52. Seepage from Oxidation Ponds. E. Idelovitch 104
53. A Comparison of Pure Oxygen and Diffused Air 119
Digestion of Waste Activated Sludge. D. B. Cohen.
54. Biomonitoring with Fish: An Aid to Industrial 131
Effluent and Surface Water Quality Control.
W. S. G. Morgan.
55. An Integrated High Rate Pond-Algae Harvesting 104
System. J. C. Dodd and J. L. Anderson.
1x
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Paper No.
56. The Dynamic Behaviour of an Anaerobic Digester 119
A. D. Carr and R. C. O'Donnell.
57. The Use of Ozone Induced Chemiluminescence in 131
Water Quality Monitoring. V. A. Garten, R. B. Head,
R. McNeill and J. M. Overbeek.
58. Development of a Rapid Fish Toxicity Test Utilizing. . . 142
a Freeze Concentration Technique for Routine
Petroleum Refinery Wastewater Monitoring.
E. C. Birchard
59. Removal of Organics in Sewage and Secondary 156
Effluent by Reverse Osmosis. E. S. K. Chian,
S. S. Cheng and F. B. DeWalle.
60. Theory and Design of High-Rate Media Trickling 178
Filters. J. A. Oleszkiewicz.
61. Compounds Toxic to Fish in Pulp Mill Waste 142
Streams. J. M. Leach and A. N. Thakore.
62. Series Intermittent Sand Filtration to Upgrade 162
Wastewater Lagoon Effluent. D. W. Hill, J. H.
Reynolds, S. E. Harris, D. S. Filip and
E. J. Middlebrooks.
63. Biological Rotating Disk Scale-up Design: Dissolved . . 178
Oxygen Effects. W. H. Chesner and A. H. Molof.
64. Nitrification in Free-Flowing Streams 146
F. F. Lopez-Bernal, P. A. Krenkel and R. J. Ruane.
65. Ion Exchange in a Moving Bed of Magnetized Resin .... 168
B. A. Bolto, D. R. Dixon, A. J. Priestley and
E. A. Swinton.
66. Uptake of Americium-241 by Algae and Bacteria 184
J. P. Giesy, Jr. and D. Paine.
67. Consideration of the Efficiency of Attached 146
Organisms in the Simulation of Self-Purification
and Oxygenation Capacity of Flowing Waters.
P. Wolf.
68. Recovery of Zinc using Chelating Resin 168
H. Uejima, M. Hirai and T. Ishibashi.
69. Nutrient Exchange Kinetics in Water Sediment 184
C. P. C. Poon.
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Paper No. Page
70. Comparison of Semi-Continuous and Continuous . ... 145
Flow Bioassays. J. H. Reynolds, E. J.
Middlebrooks, D. B. Force!la and W. J. Grenney.
71. Water Demineralization by a Thermally Regenerate. . 168
Ion Exchange. B. A. Bolto, N. H. Pilkington,
P. M. Sharpies, G. K. Stephens, K. 0. Wade and
D. E. Weiss.
72. Mercury Transport Interacting with Bed Sediment. . . 184
Movements. A. Kudo, D. R. Townsend and
D. R. Miller.
XI
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EXECUTIVE SUMMARY
Beginning in 1962, the International Association on Water
Pollution Research has held an international conference biennially.
(jThis report is an interpretive analysis 'of formal and informal develop-
ments at the Eighth International Conference on Water Pollution Research
held in Sydney, Australia, October 17-22, 1976,land has been prepared
for the U.S. Environmental Protection Agency bjpthe U.S.A. National
Committee for Representation of the United States to the International
Association on Water Pollution Research.
The Conference papers, complete with formal and informal
floor discussion, will be published in the future. Because of this,
this report does not contain the formal papers or the verbatim dis-
cussions. Rather, this report was prepared by the official U.S. par-
ticipants in the Conference as a critical analysis of formal and
informal developments at the Conference which were deemed to be of
potential interest to the U.S. Environmental Protection Agency.
Important information concerning developments in international
water pollution research was obtained both from the formal Conference
sessions and, perhaps even more importantly, from informal information
exchanged outside the formal meeting rooms. |0f particular significance
were the following:!
-U.report of possible transport of pathogens, in the
form of aerosols, for considerable distances downwind
from spray irrigation facilities using wastewater.
--suggestions that acid-fast organisms and yeasts may
be particularly advantageous in the case of disin-
fection as indicator organisms for viruses.
--the finding that the presence of gas phase ozone
substantially enhances disinfection as compared
with ozone residual alone.
-•jsgrious concern over the potential environmental
and public health hazard that may be associated
with traces of Americium 241 in water.I
--a report on a biomonitoring technique utilizing
changes in fish respiration rates as an automatic,
continuous means of detecting the presence of toxic
components in wastewater.
— recognition of the reversible nature of lime stabili-
zation of sludges as the pH of such sludges may be
reduced following land fill disposal.
XII
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-a proposal that utilization of scrubber sludges in
municipal wastewater coagulation/clarification may
offer both economies and improved performance.
-a discussion of the advantages of aerated equalization
ponds in reclamation systems leading to equalization
of influent quality, improvement in ammonia stripping
efficiencies» reduction in calcium carbonate supersatu-
ration, destruction of some pathogens and facilitation
of breakpoint chlorination.
-a report on use of magnetized resins in moving bed ion
exchangers (including a dramatic increase in settling
rate in the resin/water separation step).
-arguments presented that not even primary sedimentation
is justified prior to ocean disposal of municipal sewage.
-a detailed discussion of the operation of Melbourne's
Werribee Farm for land disposal of the City's wastewater.
-a description of a novel technique for corrosion protec-
tion of sewer lines using formed-in-place plastic liners.
-a startling claim of possible transfer of antibiotic
resistance from nonpathogenic bacteria to pathogens.
-discussion of the extended survival of enteric viruses
and coliforms in sediments around ocean outfalls with
the possibility of later unpredictable resuspension and
transport.
-a continuing emphasis and reemphasis on the importance
the wastewater reuse concept.
xiii
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CHAPTER I
INTRODUCTION
Background
This report is an interpretive analysis of formal and informal
developments at the Eighth International Conference on Water Pollution
Research held in Sydney, Australia, on October 17-22, 1976. The
International Association on Water Pollution Research sponsors such a
conference biennially. This report was prepared for the U.S. Environ-
mental Protection Agency by the U.S.A. National Committee for Represen-
tation of the United States to the International Association on Water
Pollution Research.
The International Association on Water Pollution Research
(IAWPR) 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. It is governed by representatives of
national committees of member countries. Each national committee, as a
condition of membership in IAWPR, represents the water pollution research-
related professions in the respective country.
The International Association on Water Pollution Research
recognizes the United States of America National Committee (USANC) as
the national organization representing American water pollution research
interests in IAWPR. USANC is sponsored by five major professional
societies with interests in water pollution research: (1) American
Chemical Society; (2) American Institute of Chemical Engineers;
(3) American Society of Civil Engineers; (4) Association of Environ-
mental Engineering Professors; and (5) Water Pollution Control Federation.
Each of these professional societies provides financial support to USANC
for membership in IAWPR and appoints two delegates and two alternate
delegates to serve on the U.S.A. National Committee.
International conferences of IAWPR have been held biennially
since 1962. Conferences prior to the 1976 Sydney Conference were held in
London, Tokyo, Munich, Prague, San Francisco, Jerusalem, and Paris. The
1980 Conference will be held in Stockholm and the 1982 Conference in
Toronto. The Conferences represent the largest international gathering
of researchers in water pollution control and, thereby, provide an invalu-
able mechanism for the exchange of water pollution control information by
both formal and informal means. While the remote location of the 1976
Conference resulted in below-usual attendance, over 800 individuals rep-
resenting over 30 nations attended.
The purpose of this report is not to present a verbatir record
of the Conference. Papers complete with formal and informal floor dis-
cussion and responses from authors will, in time, be published in one of
the two formal journals of IAWPR, Progress in Water Technology. Rather,
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the purpose of the report is to present a critical analysis of formal
and Informal developments at the Conference which are of potential
interest to the U.S. Environmental Protection Agency. The report rep-
resents an assessment by official American participants in the Confer-
ence of the significance of developments at the Conference. Contribu-
tions 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 developments, but includes developments from the
informal exchanges between engineers and scientists from various countries
which inevitably occur at such conferences.
The agenda for the Sydney Conference was developed by the
Program Committee of IAWPR from papers submitted from around the world
in response to invitations to submit manuscripts appropriate to any one
of 26 designated topics covering the broad area of water pollution
research. Reprints of papers selected for the program were available
to participants in advance of the Conference, and only abbreviated sum-
maries of the papers were presented by the authors in Sydney. Formal
discussers were selected by the Program Committee prior to the Confer-
ence to prepare critical analyses of each paper. Additionally, appreci-
able informal discussion of the papers and of the formal discussions
occurred. Appendix I contains the program for the Conference and pro-
vides additional information on the conduct of the sessions.
Report Development
This report was prepared by the official American participants
in the Sydney Conference. Official participants were those individuals
presenting papers, presenting prepared discussions of research work
described by others, chairing or recording sessions and workshops, and/
or participating in IAWPR Governing Board activities. Development of
the report was coordinated by a Subcommittee of USANC consisting of the
present officers (Richard I. Dick, David G. Stephan, and Richard S.
Engelbrecht) together with the immediate past chairman (Bernard B. Berger).
Prior to the Conference, the USANC Coordinating Subcommittee
ascertained the interest of official participants in cooperating in the
development of this report and solicited expressions of interest in
reviewing particular sessions at the Conference. Then, assignments for
coverage of all the sessions were made as indicated in Appendix II.
Appendix III contains the preliminary instructions given to participants
in development of this report, and Appendix IV gives the detailed direc-
tions issued to guide the preparation of individual reports.
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 unrelated to water pollu-
tion research, the reports are published here as received from the
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authors. The reports thus represent a critical assessment by American
water pollution control researchers of those sessions of the Conference
which received their special attention. The reports appear under the
by-line of the reviewers and represent their personal views—not neces-
arily the views of the Coordinating Subcommittee or USANC.
Highlights of Chapter II as perceived by the Coordinating
Subcommittee are summarized in Chapter III. Additionally, information
submitted by individual participants on developments at the Conference
unrelated to their sessions are summarized in Chapter III. The Execu-
tive 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 or workshops. 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
SESSION
A. Theme of Session: Spray Irrigation with Wastewater
B. Papers Presented: 1
Spray Irrigation with Wastewater: The
Problem of Aerosolization and Dispersion
of Enteric Microorganisms.
E. Katzenelson, B. Teltch, H. I. Shuval
(Israel)
II. REVIEWER
A. Name: Shaukat Farooq
B. Position and Affiliation: Assistant Professor of Environmental
Engineering
Department of Civil Engineering
University of Miami
Coral Gables, Florida 33124
III. REVIEW OF SESSION
A. Formal Paper
A.I Paper No. 1
A paper on spray irrigation with wastewater was introduced by
Dr. Shuval, who explained the problem of aerosolization of microorganisms
during spraying and the possible spread of human disease by contaminated
air. According to the speaker, there are some 250 communities in Israel
which at present are practicing spray irrigation with wastewater and are
thus being exposed to a health risk. The speaker also provided some new
information concerning the epidemic!ogical status of the communities
practicing spray irrigation which was not reported in their paper. The
incidence of enteric communicable diseases in 77 kubbutzins (agriculture
communal settlements) practicing wastewater spray irrigation with partially
treated, non-disinfected, oxidation pond effluent, is compared with 130
kibbutzins practicing no form of wastewater irrigation. The distribution
of ages is reported to be the same in both the groups, although the
kibbutzins utilizing the wastewater tend to have a slightly older popula-
tion since this group includes a number of larger and older well-established
settlements.
The data, obtained from the Department of Epidemiology of the
Ministry of Health, were mainly collected for enteric diseases which could
be waterborne, and include shigellosis, salmonellosis, typhoid fever and
infectious hepatitis. Streptococcal infections (including scarlet fever)
and tuberculosis, not considered to be associated with domestic wastewater,
were selected as controls. Ratios of morbidity were determined between
the settlements using wastewater effluent for irrigation and those which
did not. The results indicated that disease incidence was two to four
times higher in settlements utilizing domestic wastewater for spray
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irrigation, and ratios for shigellosis, salmonellosis, infectious
hepatitis and typhoid fever were 2.2, 3.7, 2.0, and 4.3, respectively.
No significant differences in disease incidence were seen for those
diseases not associated with wastewater (streptococcal infections and
tuberculosis). Further, no significant differences were found in
disease rates for shigellosis, and infectious hepatitis during the months
of winter (December-March) when irrigation is not practiced. These
facts strengthen the hypothesis that there exists a relationship between
irrigation with wastewater effluent and enteric disease incidence.
Finally, Dr. Shuval, after emphasizing the need for spray
irrigation with wastewater effluent in Israel but noting related health
effects, strongly recommended high levels of wastewater treatment,
including effective bacterial and viral inactivation through disinfection,
for all cases of wastewater irrigation or land disposal near residential
areas, in light of the potential public health risks involved.
B, C & D. Discussions
The authors were congratulated on raising the question of health
dangers due to the problem of aerosolization during spray irrigation with
wastewater effluent and also for providing epidemiological data about the
communities which are practicing spray irrigation. However, during the
discussion several questions were raised about the study:
1. The applicability of a theoretical model to predict a density
of microorganisms in the downwind direction is questioned
because it does not accommodate a natural die-away rate in the
atmosphere. However, improved models have been reported in
the literature which do include a natural die-away rate of
microorganisms and thus are closer to the real world situation.
2. It was suggested that the total plate count is a more sensitive
measure of bacteria in air than the Anderson air sampler with
a selective medium for certain bacteria.
3. Information was requested concerning the size and depth of
oxidation ponds and the efficiency of the aerators which would
help calculate the amount of water aerosolized. Unfortunately,
the speaker did not have the information on hand.
4. Concerning the claim by the authors that the field of spray
irrigation has been ignored, the discusser quoted that,
according to a literature survey of 1975 about 131 papers
on aerosolization have been published between 1907 and 1975.
This indicates that the field of aerosolization has not been
ignored as the authors claimed. However, Dr. Shuval rebutted
this by saying that the authors meant the effects of spray
irrigation on health of nearby communities, and not the spray
irrigation itself.
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IV. CRITIQUE OF SESSION
The authors were able to answer the question, asked quite
frequently, about the relationship between the aerosolization of enteric
microorganisms into the atmosphere from either wastewater treatment plants
or spray irrigation and the health effects on the nearby communities.
Their epidemiological data are very suggestive of an increased risk of
enteric communicable diseases among the utilizers of wastewater for spray
irrigation. This appears to be the first time this type of information
has been reported, indicating the originality of their study. At the
same time, it sounds an alarm that an epidemiological study should be
conducted in the United States among the people who are working at waste-
water treatment plants or living close to them.
Another important part of their study was the use of indicator
(marker) organisms which provided better control data. Randall and
Ledbetter (1966) showed that K2e6Ue££ae are the best indicators of
bacterial air pollution from domestic wastewater sources. This was also
confirmed by Pereira and Benjaminson (1975). However, the authors of
this paper (Katzenelson
-------
I. SESSION
A. Theme of Session: Virus Removal
B. Papers Presented: 4. Virus Retention by Soil.
K. V. Abdulla Koya, Malay Chaudhuri (India)
7. The Removal of Viruses by Slow Sand
Filtration.
S. F. B. Poynter, 0. S. Slade (Great Britain)
10. Virus Removal in Activated Sludge Sewage
Treatment.
V. C. Rao, S. B. Lakhe, S. V. Waghmare,
P. Dube (India)
II. REVIEWER
A. Name: Shaukat Farooq
B. Position and Affiliation: Assistant Professor of Environmental
Engineering
Department of Civil Engineering
University of Miami
Coral Gables, Florida- 33124
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 4
The paper, "Virus Retention by Soil," was introduced by
Dr. Engelbrecht as the authors of the paper could not attend the confer-
ence. It was shown in the study that three Indian soils, black cotton,
Kanpur silt and Lateritic, were found very effective in removing bacterial
virus MS2, which was selected as the model virus due to its resemblance to
polio, coxsackie and echoviruses. In batch studies, it was found that the
bulk of viral adsorption occurs during the first 20 minutes, then reaches
a plateau within 80 to 100 minutes. Data from a continuous flow system
showed the same trend as it was observed in the batch sorption test. The
viral adsorptive capacity of soil depends on its clay content and the
chemistry of the percolating water, e.g., pH, bivalent cations, etc. It
was also observed that viruses retained in the soil column remained active
following their sorption on soil.
A.2 Paper No. 10
Again the authors of the paper,"Virus Removal in Activated-
Sludge Sewage Treatment," were absent; therefore, it was introduced by
Dr. Malina. The objective of the study was to determine the virus
removal through an activated sludge treatment plant in the tropical
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climate of Bombay, India. Composite samples were collected to compensate
for hourly variations in viral concentration and then concentrated and
assayed for enteric viruses. The authors evaluated three sampling tech-
niques in order to establish virus removal data through the primary sedi-
mentation tank as well as through secondary treatment. The extent of
virus removal during primary settling was on the order of 41.4 to 83.4
percent, while virus removal by the activated sludge process was 90 to
99 percent under field conditions. The quantity of viruses in the final
effluent in 90 percent of the cases was equal to or less than 54 plaque
forming units (PFU)/£.
A.3 Paper No. 7
Dr. Slade, introducing the paper "The Removal of Viruses by
Slow Sand Filtration," defined the objective of the research as deter-
mining the removal of viruses through sand filters and studying different
variables which affect the efficiency of virus removal. It was found
that slow sand filters are extremely efficient in removing enteric viruses
from contaminated waters. Factors such as low temperature, high flow
rates, reduced sand depth and filter immaturity adversely affect the virus
removal capacity. Another important conclusion was that viruses and
bacteria behave similarly when passed through a filter; however, virus
removal efficiency was better than bacteria. Further, it was found that
bacterial virus T7 is an unreliable indicator of the enteric virus removing
ability of slow sand filters as its removal efficiency is greater than
that of enteric viruses.
B, C & 0. Discussions
Discussion of the above three papers is combined as they are
very much related to one another. The following comments were made:
1. It was stated that the work of Koya and Chaudhuri has provided
additional evidence about the viral adsorptive capacity of the
soil. The discusser then attempted to relate the virus removal
capacity to the rate of filtration. Further, the discusser
quoted a study by Robeck regarding the removal of viruses at
different rates of filtration, i.e., Robeck observed 90 percent
virus removal at the rate of filtration of natural ground water
movement compared to only 10 percent virus removal when flow
rate was increased to that of rapid sand filtration. In agree-
ment with this reference, the work of Koya and Chaudhuri was
able to show good adsorptive capacity of soil in the presence
of clay when the rate of filtration was equivalent to the rate
of ground water movement. This study suggests that conventional
water treatment plants do not remove enteric viruses under all
circumstances. This is a call for effective removal of viruses
by other means such as disinfection.
2. Discusser commended Rao eJL aJt. on quantifying viruses under
field conditions and considering the hourly variation in virus
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concentration by collecting composite samples. He suggested
that the virus removal data would have been more meaningful
if the viruses were detected immediately at the time of col-
lection. This would have demonstrated the efficiency of the
concentration technique as well as that of the assaying
technique.
In respect to the discussion of this paper, the discusser
presented some of his data from laboratory and field studies.
In lab studies, municipal sewage was seeded with polio I and
then fed to a continuous flow activated sludge laboratory unit.
A 2 log reduction in virus counts occurred through that process.
It was found that the removal mechanism of poliovirus depends on
attachment with sludge. Later, poliovirus was recovered from
the sludge up to 5000 PFU/gm of dry sludge withdrawn. Further-
more, virus recovery from the sludge increased as the organic
loading was increased in the system. However, a mass balance
on viruses indicated that permanent inactiyation of a virus
occurred during association of the virus with sludge. It was
observed under field conditions that at constant flow rate the
removal efficiency of enteric viruses remained constant. Fur-
ther, the virus removal efficiency was 90 to 95 percent in the
contact stabilization process.
3. It was suggested that sandy soils do not retain viruses unless
they are coated with active zooglea which is normally found in
slow sand filters. Therefore the possibility exists that sandy
soils with small clay content may not be suitable for virus
removal in water treatment.
4. Objection was made to the selection of bacterial virus MS2 as
the model virus. According to a discusser, it has been reported
that bacterial virus is removed more effectively by soil than
animal viruses. An adsorption study of MS2 virus and poliovirus
on a membrane filter exhibited a significant difference in their
adsorption behavior. According to the discusser the previous
studies have been limited to poliovirus and bacterial virus
while the remaining viruses have been neglected. It has been
shown that reoviruses do not exhibit the same adsorption charac-
teristics through aluminum gel as other enteric viruses do. As
polio and coxsackieviruses were readily adsorbed, therefore it
is expected that the behavior of reovirus in the soil will be
much different than MS2.
The discusser quoted a study showing that viruses not detected
prior to rainfall were found in the ground water after heavy
rainfalls in those areas where land application of wastewater is
practiced. This suggested that heavy rainfalls change the
environment of soil which results in leaching of adsorbed viruses
by soil under different environmental conditions.
5. The efficiency of virus removal through conventional treatment
processes is usually overestimated. It has been reported that
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ambient concentration of enteric viruses in sewage range
between 10,000-100,000 PFU/£ in Israel. Even after 95 percent
removal through a treatment plant, residual viruses will still
be quite high. This suggests the importance of disinfection
of wastewater effluent prior to its utilization in irrigation.
6. Virus removal through adsorption on soil cannot be relied
upon because it is a reversible phenomenon. Viruses can be
leached from the particle surfaces by a change in pH or organic
matter.
IV. CRITIQUE OF SESSION
The study of Koya and Chaudhuri was able to provide additional
evidence that soils containing clay are very effective in removing viruses.
However, the significance of the study would have increased immensely if
the authors had used enteric viruses as model organisms and had studied
different flow rates. An important question still to be raised is how
closely the laboratory conditions duplicate the actual field conditions
when studying the removal of viruses. In addition, the authors reported
that viruses retained in the soil column were active but no information
was given indicating whether or not the soil had an inactivation capacity.
In the past, most of the virus removal studies were conducted in laboratory
scale units using large virus inocula and provided information concerning
the removal efficiency of the treatment process. The research conducted
by Rao at at. was original because for the first time researchers were
able to determine the virus removal efficiency in actual field conditions.
Originality of the work was also indicated by the fact that the authors
tried to compensate for hourly variations in the concentration of viruses
by taking composite samples and to investigate various sampling techniques
to establish good virus removal data through the activated sludge system.
Finally, the research of Poynter and Slade was able to answer
several questions which were raised earlier concerning the first two papers.
Their study was more research-oriented and provided information about the
variables which could affect the virus removal efficiency through slow
sand filters. This study showed that slow sand filters are very effective
in removing viruses from contaminated waters and bacterial virus is an
unreliable indicator for removal of enteric viruses.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
During this session it was emphasized that it is dangerous to
translate the results of bacterial virus to enteric virus. In addition,
even among enteric viruses there are some 100 different viruses which do
not behave similarly under the same environmental conditions. Therefore,
it is suggested to introduce the broad spectrum of enteric viruses in
future studies rather than only bacterial virus or poliovirus. Before
setting any new disinfection standards, it would be advantageous to
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thoroughly understand enteric viruses. Otherwise, we will be committing
the same mistake as in the past when we chose coliform as a standard for
wastewater effluent, which does not even provide safety against bacterial
pathogens.
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I. SESSION
A. Theme of Session: General
B. Papers Presented: 13.
16.
19.
Nitrogen, Phosphate and Virus Removal from
Sewage Water During Land Filtration.
J. C. Lance, C. P. Gerba (USA)
Faecal Coliforms and Faecal Streptococci:
A Statistical Comparison using Data from
England and Papua New Guinea.
R. Feachem, K. Khan, E. Rosebergen (Gr. Brit.)
The Effect of Ozone Bubbles on Disinfection.
S. Farooq, R. S. Engelbrecht, E. S. K. Chian
(USA)
II. REVIEWER
A. Name: Joseph F. Malina, Jr.
B. Position and Affiliation: Professor of Civil Engineering
Chairman of the Department
The University of Texas at Austin
Ernest Cockrell, Jr. Hall 4.200
Austin, Texas 78712
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 13
J. C. Lance (USA) discussed the removal of nitrogen, phosphorus
and viruses in soil columns containing a loamy sand which were intermittently
flooded with secondary treatment plant effluent. The nitrogen, phosphorus
and viruses were absorbed by the soil during the flooding period. Nitrifi-
cation was observed during the drying period. Inability to elute any viruses
from the soil with distilled water after the soil had completely dried indi-
cated inactivation of the virus. In addition to the sorption of phosphorus
to the soil, precipitation of calcium phosphate was reported to be the
mechanism of phosphorus removal. A peak of nitrate in the effluent from
the columns was observed shortly after flooding columns which had been
flooded previously and allowed to dry. Introduction of a carbon source
(dextrose) enhanced denitrification; however, nitrate peak was not eliminated.
A.2 Paper No. 16
The second paper dealing with fecal coliforms and fecal strepto-
cocci was presented by the discusser, Mr. Lane (Australia). The formal
discussion and the floor discussion were more significant than the material
in the paper. These comments will be presented in Section II1.B and III.C
rather than at this point.
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A.3 Paper No. 19
The third paper, presented by Mr. Farooq (USA), discussed the
effectiveness of ozone as a disinfecting agent in a clean water system
consisting of phosphate buffer. The authors clearly demonstrated that
the ozone residual, in fact, enhanced virus inactivation and bacterial
die-off. The presence of gaseous ozone in the form of bubbles resulted
in a higher degree of disinfection than ozone residual alone. The authors
also proposed that Mt/cobaa£e/i/uun fjo-ttactum, an acid fast organism, and
Candida paftap^oA-u, a yeast found in domestic sewage, nay be candidate
organisms for possible indicators because of their resistance to changes
in the environment as well as to ozone.
B. Prepared Discussions
B.I Mr. Ray Rimkus presented the formal discussion of Paper No. 13
prepared by Mr. Cecil Lue-Hing of the Metropolitan Sanitary District of
Chicago. He pointed out a number of discrepancies in the paper as the
authors interchangeably used secondary effluent with sewage water. In
fact, in the paper there are no general characteristics of the water applied
to the soil columns. The possible problem with leakage of nitrogen to
the ground water also was pointed out. The hypothesis of calcium phosphate
precipitation in the soil column was not verified since there were no
samplings of the material in the column. In fact, the measurement of the
variation of pH in the column would help verify if calcium phosphate pre-
cipitation did in fact take place. Therefore, the removal of phosphates
by chemical precipitation seems to be more effective and more controllable
than using soil systems. It also was pointed out that the phosphorus in
the effluent of 12 mg/£ was relatively high and was not typical of secondary
effluents which would have phosphorus concentration of 1 to 2 mg/£.
They also pointed out that in the Fulton County experiments with
viruses in sludge, viruses only traveled 1.3 cm after distilled water was
applied to the soil. However, in Fulton County the soil has a much higher
clay content than the 3 percent clay reported for the soil in the Phoenix
operation. The need to evaluate the soil characteristics at each specific
site along with the chemical composition of the wastewater to be applied
was strongly recommended.
B.2 Mr. D. J. Lane (Australia) discussed the paper on fecal coliform
and fecal streptococci (Paper No. 16) and questioned whether the experi-
mental work reported in the paper was in fact designed as a statistical
exercise rather than interest in fecal coliform and fecal streptococci
as indicator organisms. The variations may be inherent to any lab analyses
and statistically the fecal streptococci seem more appropriate, especially
from a taxonomic and physicological point of view. However, Mr. Lane did
question the sanitary significance of fecal streptococci and presented
some data from South Australian streams. At normal flow, E. co&t and
fecal streptococci were presented in the same numbers. However, during
high flow periods the E. c.oti are much greater in number than the fecal
streptococci. During low flow periods no trend was obvious. In
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unpopulated areas; therefore, the E. cote were the more significant
indicators. He also pointed out that the fecal streptococci data should
be used to substantiate the E. co&i. data.
B.3 Dr. W. Stumm (Switzerland) discussed ozone disinfection (Paper
No. 19). He stressed the need to understand the speciation of ozone
before investigating disinfection, much like it was necessary to understand
the various species of chlorine before investigating disinfection. The
understanding of the speciation of ozone is very limited. Ozone is very
reactive and will react with hydroxyl (OH") ion or other materials to form
hydroxide radicals which will carry on other reactions with the substrate.
He stressed the effects of pH, organics in the water, and other chemical
constituents on the species of ozone which would be present. The phosphate
buffer system used by the authors was different than the carbonate buffer
systems in which bicarbonate acts as a scavenger of the OH radical and
stabilizes the ozone. However, ozone residuals were much more important
than the hydroxide radicals in disinfection.
The bubbles of ozone on disinfection were not significant. Dr.
Stumm pointed out that the ozone bubbles may cause flotation and carry
the bacteria to the surface of the liquid at which point the bacteria are
transferred to the gas phase when the bubbles burst. The detention time
in treating wastewater with minimum ozone residuals is significant since
the wastewaters have an oxygen demand and, therefore, an ozone demand.
The significance of the bubble size cannot be determined from a laboratory
system which is 50 cm tall since most of the installations in the field
are 2 to 3 meters deep. However, Dr. Stumm did commend the authors for
their diligent effort in looking at a continuous flow system. He felt
additional work had to be conducted before a more complete understanding
of the use of ozone as a disinfectant could be applied more universally.
C. Floor Discussions
C.I A number of significant factors were brought out in the discussion
of the use of soil systems for removal of nutrients and viruses. The pos-
sibility of removing the phosphorus by pretreatment with lime precipitation
and disinfection of the effluent to eliminate viruses and pathogens was
suggested along with the high pressure spray to prevent soil plugging with
suspended solids. Dr. Lance indicated that the use of lime would prevent
clogging. However, the need for pretreatment was dependent on the quality
of the effluent applied to the land. He pointed out that the wetting and
drying of the soil prevented clogging, although clogging was more preva-
lent when using the effluent from an activated sludge plant containing
10 mg/t of suspended solids compared to the application of primary sewage
containing several hundred mg/£ of suspended solids. Apparently the
primary sewage solids are more easily degraded and allow for high appli-
cation rates.
A question was raised regarding the length of time and rate at
which wastewaters could be applied to vegetated areas before the grass
would die. Dr. Lance pointed out that the use of flood tolerant grasses
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would be more acceptable than the Bermuda grass which was used in the
vegetated column experiments. The tremendous differences between differ-
ent soil systems were also pointed out. Some contain heavier clays which
would provide for more adsorption of viruses while others contained very
little clay. It was also pointed out that it is extremely difficult to
predict and extrapolate data from one site to another and that it is
essential that the characteristics of the soil at specific sites be care-
fully characterized and constituents identified. Possibly in the future,
a sufficient data bank of information would be available regarding various
soils to at least provide a starting point in looking at the applicability
of various soils to water reclamation systems. Dr. Lance indicated that
the soil in the Phoenix area contained only 3 percent clay and that with
heavier clays you find less movement of viruses. Mr. Rimkus made a
similar point.
Dr. Lance felt that the movement of nitrates into the ground
water would lead to a contaminated situation and suggested that pumping
the reclaimed water with a portion of the ground water would minimize
nitrate buildup in the ground water. Dr. Lance also pointed out that he
had no direct evidence of phosphate precipitation, although removals of
6 to 8 mg/£ were observed and that the calcium content in the effluent
from the columns was greater than the effluent. The effectiveness of the
soil system in removing phosphorus after all the calcium was flushed from
the system was questioned.
C.2 Dr. Shuval (Israel) led off the floor discussion on fecal ccli-
form and fecal streptococci by pointing out that the significance of the
organisms from a public health point of view instead of as a statistical
convenience should be the prime consideration. He pointed out that E. coti,
fecal coli and fecal streptococci in raw sewage are relatively constant in
number. However, the fecal streptococci have more resistance and, there-
fore, will survive longer in the environment and the die-off is less rapid
than that observed for E. co&c and fecal coli. Therefore, he questioned
the efficiency of coliforms as indicators of pathogens and proposed that
fecal streptococci behave more similarly to viruses in the environment.
The survival of salmonella, €. c.oti and viruses in marine environment were
reported. The Tgg was 45 minutes for E. c.oLi and many salmonella strains.
However, other strains of salmonella were more resistant to changes in the
environment. On the other hand, the Tgg for enteroviruses was 24 hours.
The question was raised by Rao of India whether there should be
more parallelism between the indicator organisms and pathogens. The
organisms should indicate the presence of pathogens, and the analysis of
water to indicate the possible presence of fecal pollution did not neces-
sarily indicate the presence of pathogens. The relative significance of
coliform and fecal streptococci was pointed out. In ground water near
Nagpur, India, fecal streptococci were detected but no coliform organisms
were observed. Animal feces contained a much higher concentration of
fecal streptococci than fecal coliform. Therefore, the fecal strepto-
cocci indicate animal pollution. Fecal streptococci, which survive longer
than the fecal coliform, would be more indicative of pathogens.
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C.3 The criteria for an indicator organism were reiterated during
the discussion, namely that the organism is more resistant than pathogens,
although not a pathogen itself, and is easily analyzed and ubiquitous.
Other organisms have also been proposed as indicators in the formal paper
presented by Mr. Farooq. Using a combination of coliform and fecal
streptococci would be more useful in identifying the source of fecal
pollution. Bruce Hanes (USA) felt that the main point of the paper,
namely the study of the statistical variations of the present test being
used, was not understood by the audience. We must understand the sig-
nificance of the variation and the analytical procedures before we can
fully utilize any indicator organism in assessing pollution.
Coliform has been used in conjunction with fecal streptococci
for a long time in France. This work must be continued in order to develop
the relative significance of these organisms as indicators of the presence
of pathogens. However, the blind application and the usefulness of the
ratio of fecal streptococci to coliform is questionable.
Dr. Chian (USA) directed comments to Dr. Stumm's discussion and
agreed that the mechanism of ozone disinfection must be approached in a
similar fashion as the work on chlorine disinfection. However, he felt
that first indications are that the ozone, in fact, enters the cell and
acts intracellularly. Therefore, the transfer of ozone into the cell
affects disinfection and the higher the concentration of ozone in the bulk
liquid, the higher the transfer of ozone into the cell. The question of
temperature effects on disinfection was also raised. Mr. Farooq indi-
cated that as the temperature increases the ozone concentration in the
bulk liquid is reduced, and therefore the disinfection rate is reduced.
Dr. Wachs (Israel) pointed out that in studies in which he was
involved, quasi-residual persisted in water even though a residual ozone
was not measured, and disinfection continued with seeded bacteria in the
system. Dr. Stumrn pointed out that the rate of reaction is based on many
factors. Dissolved ozone is, in fact, a disinfectant and the residual
ozone is a function of the organic concentration in liquid, the bicarbo-
nates and the OH" decomposition. The radicals formed during ozonation
may be involved in the quasi-residual mentioned by Dr. Wachs.
IV. CRITIQUE OF THE SESSION
The material presented in the three papers in this session was
quite diverse. The use of soil systems to reclaim water in arid or semi-
arid areas is quite acceptable throughout the world. Heavy metals in
the applied wastewater are potential problems. The efficiency of phos-
phorus removal in soils systems was questioned, and the concensus seemed
to be that removal of phosphorus by chemical precipitation is more effec-
tive. Complete nitrogen removal also is not possible with the soil system.
Therefore, there are some risks involved in reclaiming water from a soil
infiltration system. However, the retention of viruses in the soil is
significant. Extrapolation of data from one soil system to another can
be extremely hazardous and should be avoided.
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The use of the coliform organism as an indicator seems to be
universally accepted. However, it is apparent that the use of a more
resistant bacterium, such as fecal streptococcus in conjunction with the
coliform analysis, can provide more useful or meaningful information.
However, the total absence of an indicator organism does not guarantee
that viruses are not present in the water. Although the use of an acid-
fast organism and a yeast was proposed, there was no uniform acceptance
of these organisms as replacements for fecal coliform or fecal streptococci.
The effectiveness of ozone as a disinfectant in a clean water
system consisting of a phosphate buffer was demonstrated. However, the
chemical reactions of ozone in waters which contain organic material and
other reacting material is far from being completely understood. An ozone
residual or quasi-residual is responsible for bacterial disinfection,
although speciation of the ozone in clean water systems will aid in develop-
ing the fundamental understanding of ozone as a disinfectant. The work
must be expanded to evaluate the effectiveness of ozone as a disinfectant
by using wastewater treatment plant effluents which contain organic mater-
ial and other substances which will exert an oxygen demand and therefore
an ozone demand. A major advantage of ozone is the fact that, at the
present time, there is no product of ozonation other than the quasi-
residual which persists in a similar fashion as do chlorinated orgam'cs.
Therefore, ozonation of secondary effluent may provide a step in the right
direction in eliminating potential toxic or possible carcinogenic materials
in natural water which may eventually be a source of water supply to other
communities.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Soil systems and land have been used for the reclamation of
wastewater as well as for the disposal of wastewater ranging from raw
sewage to effluents from biological treatment facilities. A variety of
papers dealing with different aspects of wastewater disposal or reclamation
using land systems were presented at the conference. Detailed reports are
being prepared by other individuals; however, it is necessary to draw on
some of this information in identifying significant and future research
needs. The application of wastewater with or without treatment to the
land must be reviewed in the context of the overall objective of the sys-
tem, mainly wastewater disposal, reuse of water for irrigation of edible
crops or animal fodder, or infiltration for reclamation of water. In all
cases the characteristics of the soil system must be defined, and the
capacity of the soil system established. Specifically, additional infor-
mation is required in the following areas:
1. The significance of the clay fraction in the soil and the
absorption and retention of nutrient and cations, especially
heavy metals
2. Identification of the reactions which take place in the soil,
in particular those resulting in the removal or transformation
of nitrogen and phosphorus
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3. The exchange capacity of the soil and the leaching of cations
from soil, as well as tolerance of the soil and vegetation to
various cations and salts in general
4. The introduction of additives to the soil to enhance infiltra-
tion rates as well as specific reactions for the removal of
pollutants
5. Characterization of the soil with regard to the acceptable
application rates of liquids and the capability of these soils
to retain pollutants
6. The pretreatment requirements dictated by the capacity of the
soil prior to application and other factors which affect
bacterial die-off and virus inactivation, specifically the
composition of the soil and the ability to retain viruses and
bacteria
7. The significance of desiccation of the soil system on virus
inactivation and bacterial die-off
8. The effects on pathogens of exposure to sunlight of wastewater
during application for infiltration or irrigation
The shortcomings of using E. c.oli as an indicator organism in
natural waters have been identified. Specific questions which must be
answered include:
1. Would the use of fecal streptococci or fecal coliform be more
representative of the presence of pathogens in water systems in
the United States than in other parts of the world?
2. Should an indicator organism also be responsive to changes in
the environment in the same way as enteroviruses?
3. What is the statistical validity of analyses for fecal
streptococci and possibly enteroviruses?
The use of acid-fast organisms or yeast as indicators of the
quality of water does not seem very practical although these organisms may
be more representative of the response of enteroviruses to environmental
changes. If viruses are the main target of indicator organisms, it seems
that a system can be developed whereby field personnel can concentrate the
viruses in water samples and store these samples under refrigeration for
subsequent analysis in a central laboratory equipped for assaying samples
for viruses.
The question of indicator organisms in the United States is
somewhat a moot point since the number of indicator organisms, pathogens
and viruses is markedly reduced during biological treatment of municipal
wastewater. If the 1977 guidelines of the PL 92-500 are to be met, munici-
pal and industrial effluents will have secondary treatment before discharge
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into the navigable waters. The benefit of indicator organisms would be
in identifying non-point sources of pollution. The transmission of
diseases through the water route is also addressed in the safe drinking
water legislation. Adequate treatment of water supplies, including dis-
infection, should continue to reduce the transmission of diseases via the
water supply system.
Ozonation for the disinfection of secondary effluents from
municipalities should be evaluated in light of the fact that disinfection
with chlorine results in the formation of chloramines and chloro-organic
compounds which may have toxic effects on aquatic organisms and potential
carcinogenic effects on humans. The compounds which provide the quasi-
residual effect in ozonated water should be identified to establish any
long lasting residual effects on the aquatic system.
Understanding of the mechanism of disinfection with ozone is of
significance if ozone is used for the disinfection of drinking water sup-
plies. In this connection the speciation is important in order to optimize
the process. However, in the case of disinfecting biologically treated
municipal wastewater, the ozone demand exerted by the residual organic
compounds and other chemical constituents of the wastewater is significant.
Other factors, such as contact time and required dosage as well as temper-
ature effects, should be established in order to develop proper guidelines
for design and operation of ozone systems for disinfecting biologically
treated wastewaters.
-19-
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I. SESSION
A. Theme of Session: Lakes and Reservoirs Water Quality
B. Papers Presented: 2. Great Lakes Water Quality Agreement.
J. P, Bruce, P. M. Higgins (Canada)
5. Localised Destratification of Large
Reservoirs to Control Discharge Temperatures.
F. L. Burns (Australia)
II. REVIEWER
A. Name: Vladimir Novotny
B. Position and Affiliation: Assistant Professor, Department of
Civil Engineering
Marquette University
Milwaukee, Wisconsin 53233
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 2
A paper describing activities under the auspices of the Inter-
national Joint Commission established in 1972 by an agreement between the
USA and Canada and summarizing Canadian participation was presented. The
paper is very descriptive, dealing basically with the organization of IJC,
ongoing projects and goals. The paper itself does not present information
not already known to U.S. participants in IJC related projects.
A.2 Paper No. 5
The paper describes an investigation involving hydraulic model
studies to develop a destratification installation for a large reservoir
in Victoria, Australia. Australian limnologists, unlike those in the U.S.,
are concerned with cold temperatures downstream from reservoirs as a
result of releasing cold hypolimnic waters. Many species of native fish
require warm water in spring or early summer for breeding. The options
investigated by the River Murray Commission included construction of a
model with multi-level outlets equipped with an aeration device and high
energy water jets located in the vicinity of the outlet, to produce
localized destratification and, thus, provide control over discharge
temperatures.
The model test results indicated that the most effective destra-
tification arrangement was a combination of a water jet and an aeration
curtain. The water jet alone tended to dissipate its effect over a wide
area, the currents spreading quickly along the thermocline. The introduc-
tion of an aeration screen, bubbling air up from the bottom across the
-20-
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path of these jet induced currents, tended to throw the jet current back
onto itself and produce concentrated mixing in depth. Aeration alone
tended to produce mixing mainly above the thermocline. The authors did
not provide information or energy requirements for such a system.
B. Prepared Discussions
8.1 A prepared discussion of Paper No. 2 was presented by K. W.
Lewis (Australia) who was also chairman of the session. His discussion
focused on several questions related to the Australian view on the program.
It was evident from the formal paper that much of the phosphorus reduction
from the point sources has been already achieved. But phosphorus from
non-point sources is sufficient to sustain eutrophication. A question
arises whether nitrogen removal will be required.
Another question or comment was directed to enforcement of pol-
lution control measures. The government of Australia usually considers
the economic status of a region before enforcing strong pollution control
measures. Among the factors of interest are level of unemployment,
development needs, etc. The discusser also inquired as to the number of
people working on the program and size of the IJC staff.
Mr. Higgins pointed out that IJC is facing an overwhelming task.
There are 29 permanent employees but IJC also relies on external committees,
and on research programs being conducted by various research institutions.
A substantial number of man-hours is devoted to IJC tasks by U.S. and
Canadian nationals who are not part of the IJC staff.
The nitrogen reduction problem will be solved in the future.
It is known that phosphorus was stimulating eutrophication in Lake Erie
and Lake Ontario, and it is realized that land drainage is a significant
source of phosphorus.
Industrial and government enforcement experience (in Canada -
comment by the reviewer) is not different from Australia. The Canadian
paper industry has been given 10 to 15 years to cleanse their wastewater
effluents.
B.2 The formal discusser of Paper No. 5 (L. H. James, South Africa)
pointed out that the destratification system design employing water jets
could lead to uneconomic energy consuming solutions, particularly when
high energy water jets are used. It appears that an aeration only system
would achieve the same result at considerably less operating cost than
the water jet and aeration solutions proposed in the paper. Energy require-
ments for the destratification system proposed in the paper were estimated
by the discusser as follows:
Air only 92 kw
Air plus water jets 511 kw
Inefficiency of the Australian system is due to the use of high
-21-
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kinetic energy water jets. Economy could have been improved if large
volume low velocity water jets had been used, Until 1976 localized
destratification had not been attempted in South Africa. Consideration
is now being given to a localized destratification installation to
intercept a high density current caused by a highly mineralized tribu-
tary to a major water supply reservoir for Johannesburg, South Africa.
In response to the formal discusser's comments, the author pro-
vided some indicators on economics of the system. It has been estimated
that a multiple-level outlet would cost A$1.5 mil while the proposed
localized destratification would cost about A$360,000 (capital and oper-
ation cost based on 6 months operation). He also pointed out that the
proposed system is experimental only.
C. Floor Discussion
C.I Seven discussers participated in the floor discussion of Paper
No. 2. About half of the contributions were seeking clarification, e.g.,
how was the agreement reached, what are the expenditures, what is the
effect of the economy on the IJC activities (Mr. Kennedy-Good from New
Zealand), in how many cases was the targeted phosphorus concentration of
1 mg/£ in sewage effluents met (Mr. Zielstra from the Netherlands).
These questions were satisfactorily answered by the speaker.
Two discussers questioned the statement that phosphorus is the
limiting nutrient accepted by IJC for the Great Lakes. Mr. Kinspord from
New Zealand noted that once the lake becomes eutrophied, natural sources
of phosphorus and phosphorus recycle can sustain eutrophication and in
this case nitrogen becomes the limiting nutrient. Most of the phosphorus
loading is associated with sediment and practically independent of the
wastewater input. In response, Mr. Higgins stated that phosphorus was
stimulating eutrophication in Lakes Erie and Ontario but it has been
realized that land drainage is a more significant source of phosphorus
than waste effluents. There is no question that nitrogen control will be
considered in the future. Mr. Novotny (USA) pointed out that some of the
significant pollutants (phosphorus, ammonia, heavy metals, pesticides)
can be readily adsorbed by sediments. A large portion of sediments is
deposited in estuary and harbor areas of the Great Lakes tributaries and
may never reach the lakes. Thus, the loadings of these pollutants carried
by the tributaries may not be the same as the loading to the lakes.
In replying, Mr. Higgins said that he recognized the problem, and
he stated that the role of estuary and harbor areas as a sink for pollutants
will be addressed to a greater extent in the future. Mr. Ellis (Canada)
questioned the concept of "mixing zones" where the IJC quality objectives
are not expected to apply. He stated that such a concept is controversial
since it brings receiving waters into the treatment process. In replying,
the speaker stated that the new IJC recommendations do not propose abandon-
ing water quality objectives in the mixing zones.
-22-
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C-2 in the floor discussion of Paper No. 5, Mr. Sommerville
(Australia) noted that no target discharge temperature was specified.
The author answered that biologists were unable t9 provide any specific
answer as to the minimum downstream temperature. 'Mr. McPhee (Tasmania-
Australia) pointed out that the only danger he saw in discharging colder
hypolimnic water was increase in corrosion. Large sums are involved in
the destra,tification systems. How were the benefits evaluated - the
answer was that the benefits are synonymous with satisfying conservation
interests downstream from the reservoir.
The Australian discussers reported on reservoir stratification
in their area of interest. In Queensland all reservoirs have low land
tributaries and the thermocline can be found about 2 m below the surface.
In the Sydney area, the thermocline is at a depth of 6 m.
In concluding the discussion the speaker pointed out that local
destratification needs about one half the energy input as compared to full
destratification. However, once a small reservoir is fully destratified
it stays destratified while local destratification will return to strati-
fication overnight.
D. Other Observations and Comments
Further details on the project can be obtained from State
Rivers and Water Supply Commission of Victoria, River Murray Commission
or Hydraulic Experimental Station, Werribee, Australia.
IV. CRITIQUE OF SESSION
The first paper was very well received. The paper provides
good information on the organizational structure and activities of the
International Joint Commission. The major discussion topics in and out
of the lecture hall included experience with large scope international
cooperation, effect of economy on policy for enforcing pollution control
measures and problems of eutrophication. The discussion somehow questioned
the strong emphasis on phosphorus removal only and participants expressed
their experience as to the limiting nutrients for eutrophication control.
As stated in a previous section, some experts from Australia and New
Zealand were more in favor of nitrogen control rather than phosphorus
control.
The effect of economics on national policy for pollution control
in the USA and Canada on one side and Australia and New Zealand on the
other side also substantially differs. The Australian government does not
strongly enforce pollution control measures in areas with such problems as
high unemployment.
The second paper seemed more controversial since it represented
a report on an initial phase of the research. Failure to evaluate the
economics of the proposed system was criticized by the formal discusser.
-23-
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From the discussion it seems that localized destratification can be
achieved cheaply by aeration only at an expenditure amounting to about
20 percent of the proposed system.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Two problems emerged in the discussion of the first paper, first
the problem of nitrogen control in waste effluent to the Great Lakes, and
second, the problem of pollutants adsorbed on sediments and estimation of
what fraction of sediment adsorbed pollutants will reach the lakes and
what fraction will be deposited in estuaries and harbor areas. The paper
itself reports on pollution control activities in Canada and the U.S. and as
such it does not represent a contribution to U.S. water pollution problems.
From the discussion of the latter paper it was evident that the
research did not reach its final stage. However, there is one point the
U.S. water pollution research programs should find interesting - Australians
do not accept the notion of cold water streams downstream from a reservoir.
They want to maintain the original warm water fish and biota population.
Thus, their emphasis is on warming reservoir releases rather than supplying
high amounts of oxygen to limited downstream reaches which are to be used
for trout fishing. The costs and benefits of the two approaches should
be evaluated for U.S. conditions.
-24-
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I. SESSION
A. Theme of Session: Surface Water Quality
B. Papers Presented: 8. A Multidimensional Analysis of the Results
of the French 1971 Surface Water Quality
Network Control in the River Basin
"Seine-Normandie"
Y. LeFoll, R. Pinoit, A. Lesouef (France)
11. Hydrodynamics of Bubble Plumes and Oxygen
Absorption in Stratified Impoundments.
F. Rayyan (Saudi Arabia), R. E. Speece (USA)
II. REVIEWER
A. Name: Vladimir Novotny
B. Position and Affiliation: Assistant Professor, Department of
Civil Engineering
Marquette University
Milwaukee, Wisconsin 53233
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 8
A new method of statistical analysis of water quality surveillance
data was presented in the paper. The data information matrix for the
basin Seine-Normandie in France for the year 1971 represented 1800 samples
with a total of 50,000 water quality parameter values. The analysis was
based on classification of all samples to get a limited number of categories
according to the concentration levels of the measured parameters. The
method which was used was a multidimensional statistical technique called
"correspondence factorial analysis." It positions a sample in a space
which has as many dimensions as the total number of available parameters.
By looking at the shape of the volume thus created, it is possible to iden-
tify the parameters, the variation of which plays the most important role
in describing the various aspects of pollution. By this method it is also
possible to regroup all the samples which are close together in this
multidimensional space and by that different water types can be defined.
The volume created by the sample results placed in the multi-
dimensional space is projected on a limited number of plane sections,
determined in such a way that they represent as much as possible the main
characteristics of the shape of the volume. These plane sections are
determined by the inertia axes of the volume. The F] axis is usually a
water quality axis represented by such parameters as BOD5, COD, NH^"1" and
DO. The F2 axis is mainly affected by flow. In order to use the statis-
tical technique for water quality evaluations, the multidimensional space
-25-
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is divided into segments according to various water quality classes. The
classes are based on French water quality criteria which divide water
quality into five quality grades (see Fig. 8 in the original paper
and in Fig. 1 attached). Adding hardness and salinity of water and
including low flow-high flow quality separation, 13 water quality groups
were identified in the Seine-Normandie basin and graphically plotted on
water quality maps.
A.2 Paper No. 11
The paper introduces a modified computer mathematical model
describing hydrodynamic behavior of bubble plumes within stratified
reservoirs. The model was calibrated initially using a controlled labor-
atory system. The actual plume diameter and centerline velocity plots
versus elevation were correlated with the computed values provided by the
model. The observed and predicted stopping points of the plume were also
correlated. The model was then correlated with field data from bubble
plume generated in a 30 m (95 ft) stratified lake. The observed and pre-
dicted results agreed within 10 percent. This agreement was considered
by the authors as satisfactory and, subsequently, they used the model to
design a full-scale hypolimnium oxygenation system for Clark Hill reser-
voir near Augusta, Georgia.
Since the authors ruled out the use of air for destratification
due to anticipated danger of nitrogen supersaturation, commercial oxygen
was used instead. The oxygen plume can be designed to provide 90 percent
absorption of oxygen by water without destroying the stratified conditions
which provide the cold temperatures required downstream for trout.
The author in hi* presentation stated that in the USA there were
almost 100 impoundments with hypolimnium DO concentrations of 0-1 mg/£.
The downstream reaches which are supplied by the oxygen lacking hypolimnic
water are usually designed as trout streams. The effectiveness of tail race
aeration seems to be very low (only up to 1 mg/£) and very expensive.
B. Prepared Discussions
B.l Formal discussion of Paper No. 8 was by J. J. Wright (Australia).
His discussion was focused on various clarifying questions. The questions
touched the problem of site sampling* site selections which seemed to be
based on a trial-and-error basis rather than on an optimal solution.
Another problem raised by the discusser was separating seasonal and geo-
graphical water quality effects. The cost of such monitoring programs is
also of interest. The increase of pollution with flow should be also
explained. The paper itself does not provide enough information to permit
an understanding of the method of data evaluation, the statistics involved,
and the relationship of water quality to water uses. In answering the
discussers questions, Mr. Lesouef stated that the cost of the monitoring
program for the year 1976 was F 8 mil (5 F = $1) and the cost of evaluation
of the results was F 0.4 mil. French water quality grades are related to
-26-
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water uses, e.g., grade 1A represents water usable for water supply. The
method can be used for separating point and non-point sources (except for
nitrates). Site to site variations are more important than seasonal vari-
ations. The results of the 1971-1973 programs were used to amend the 1976
program. In the 1976 program the frequency of data acquisition was reduced
according to the variability of the parameter in the previous years and
degree of correlation between the parameters.
In conclusion Mr. Lesouef stated the present French water pollu-
tion control policy:
1. Keep rivers clean that are already clean.
2. Reduce pollution and keep it reduced.
B.2 The formal discussion of Paper No. 11 was presented by P. A.
Krenkel from USA. In his discussion Dr. Krenkel criticized several points
of the paper:
1. It should be understood that presence of cold water does not
automatically mean the classification of the stream as trout
reach.
2. Nitrogen supersaturation is unlikely to occur.
3. Size of bubbles varies but this factor was not included in the
model.
4. Transfer rate is proportional to the diameter of bubbles.
5. Increase of bubble size during its rise should be anticipated.
6. Pressure will have effect on oxygen saturation value.
7. Effect of surfactants can be quite significant.
8. Experimental data are very sparse; many times only one point
is used for comparison of the model or the measured data.
In answering, Dr. Speece stated that nitrogen supersaturation
is very difficult to measure. First mortality due to the supersaturation
of water by nitrogen was noticed on the Columbia River. Size distribution
of bubbles was approximately 1 mm. Coalescence of bubbles was not included;
however some coalescence was observed in the laboratory. Nitrogen is
stripped from water by pure oxygen into the bubbles, but due to the high
hydrostatic pressure stripping is retarded and very low. Effect of sur-
factants was not included and was considered negligible.
C. Floor Discussions
C.I The vagueness of the method proposed in the paper was one of the
-27-
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problems. Only few questions were raised and they related to the following:
1. Difficulty in understanding the method and interpreting the
figures.
2. Relation between the model and evaluation of water quality.
3. Seasonal effects, time effects and daily fluctuations.
4. Distinguishing between point and non-point sources and identi-
fication of sources of pollution.
In responding, the author stated that the method is still being
developed and improved. It provides a good tool for evaluating large
water quality data matrices.
C.2 Mr. Berns from Australia asked about the economic value of trout
fishing downstream from the reservoir. Dr. Speece pointed out that the
question is not one of economics but a political matter imposed by Congress.
Mr. Jones (Australia) asked about the effect of oxygenation on the concen-
tration of heavy metals which have a tendency to go into solution if oxygen
is added. Dr. Speece replied that the authors did not look into this
problem. It was his opinion that since the DO level usually does not go
down to 0 mg/£, the transformation of S04= to S= does not take place, a
condition necessary for precipitation or dissolving metals.
A question was raised as to the availability of diffusers and
problems associated with installation and operation. The question was
answered both by Dr. Speece and Dr. Krenkel. Dr. Krenkel related the use
of aeration and oxygenation equipment to energy resources. In the present
enery crisis the process seems to be uneconomical. Dr. Speece compared
use of pure oxygen with diffused air systems and surface aerators. Sur-
face aerators are extremely costly. Pure commercial oxygen seems to be
more efficient than diffused aeration.
D. Other Observations and Comments
Since the explanation of the statistical method used by the
French scientists to evaluate water quality data was not quite clear, Mr.
Lesouef was contacted during the conference and provided a more detailed
explanation. The method evaluates water quality data in a multidimensional
space. Each dimension represents a water quality parameter. A three
dimensional case is shown on Figure 1. Each water quality sample represents
a point in this multidimensional space. The volume occupied by the points
is then transformed and plotted with its axes of inertia as coordinates.
This transformation then enables the subsequent evaluation.
The method is described in several(French scientific reports,
e.g., Benzecri, J. P., "La 'analyse des donnees," or Diday, M., "La
methode des nuees dynamiques."
-28-
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IV. CRITIQUE OF SESSION
The first paper described a new quite original method of evalu-
ating large water quality data matrices. The paper, however, was not
clear as to the description of the method and data matrix transformation
into the two-dimensional linear graph. However, the paper was well
received by the formal discusser and session participants. Many scien-
tists from different nations inquired as to the availability of a better
description of the method used in the paper.
The second paper had the usual handicap of papers dealing with
mathematical models, i.e., many equations; therefore, only very few people
were able to comprehend the presented material. Several shortcomings were
pointed out by the formal discusser who stated that insufficient experi-
mental data (especially controlled laboratory data) were presented to
document the validity of the model.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
As was stated earlier the first paper introduces a relatively
new statistical technique applicable to large water quality data matrices.
Although more information from French authors and from the Seine-Normandie
basin staff is necessary, its applicability should be tested in the U.S.
With few exceptions such as ORSANC, Delaware River system, and some others,
a comprehensive water quality surveillance program is relatively new to
this nation and few scientific methods exist for evaluation of the data.
The French method is not simple statistics, but rather a sophisticated
statistical transformation model and it seems very promising.
The second paper was developed in the USA and reports on
research activity which has been conducted in this country for years.
Plume rise models have been developed at other research institutions in
this country, such as MIT, California Institute of Technology, Tennessee
Valley Authority, Vanderbilt University and others. It is very difficult
to ascertain which model is the best and under which conditions.
-29-
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PH
SPACE OCCUPIED
BY SAMPLES
FLOW
FIG. I WAT. QUALITY DATA TRANSFORMATION
-30-
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Water Quality Standards
Quail te
(1) Temp, eau
1
1
1
1
1
2
1
lj
PH
02 dissous mg/£
i Ind. de satur. %
DBOs mgAt
DCO
S04
NH4
NOs
TJ Phenols
iT
(2,
Orthophos. "
Deterg. Anion "
1A
<20
6.5-8.5
>7
>90
<3
<20
IB
20-22
6.5-8.5
5-7
70-90
3-5
20-25
2
22-25
6.5-8.5
3-5
50-70
5-10
25-40
<250
<0.1 0.1-0.5
0.5-2
<44
<0.001
<0.4 0.4-0.7
<0.2
0.001-0.05
3
25-30
5.5-9.5
<%
4
>30
<5.5 ou >9.0
<50
10-25
40-80
>25
>80
>250
2-8
44-100
0.05-0.5
>8
>100
>0.5
>0.7
0.2-0.5
>0.5
T
2
2
2
(2
2
2
2
1
1
2
1,
CN
Cr
F
PB
Se
Cu
Zn
As
Fe
Mn
Cd
Subs. Extrac. "
<0.05
<0.05
<0.7
0.7-1.7
<0.05
<0.01
<0.05
0.05-1
<3 3-5
<0.05
<0.5
<0.1
0.5-1
O.T-Q.25
0.05-0.1
1-1.5
0.25-0.5
<0.005
<0.2
0.2-0.5
0.5-1
>0.05
>0.05
>1.7
>0.05
>0.01
>1
>5
>0.1
>1.5
>0.5
>0.005
>1
r
2;
E. coli N/100 mi
Streptoc. " "
<2000
<20
20-1000
>2000
1000-10000
> 10000
(T"
Llj
I. Lentique
I. Lotique
>9
>9
7-8
7-8
5-6
5-6
3-4
3-4
<2
<2
Salinite
(1) Conductivite
(1) Cl
0
<400
<100
1
400-750
100-200
2
750-1500
200-400
3
1500-3000
400-1000
4
>3000
>1000
Fig. 8
-31-
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I. SESSION
A. Theme of Session; Groundwater Pollution
B. Papers Presented: H. Technical Requirements and Analysis Methods
for Evaluating the Environmental Conse-
quences of Groundwater Contamination.
R. W. Nelson (USA)
17. Pilot Plant Investigation of the Evolution
of Various Pollutants During Artificial
Recharge of an Aquifer by a Basin.
M. Rizet, J. Malleviale, J-C. Cournarie
(France)
20. Hydrochemical Effects of Waste Percolation
on Groundwater in Basalt near Footscray,
Victoria, Australia.
M. Riha (Australia)
II. REVIEWER
A. Name: T. E. Larson
B. Position and Affiliation: Head, Chemistry Section
Illinois State Water Survey
Urbana, Illinois 61801
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 14
This is a rather thorough scholarly evaluation of technical
requirements for analysis of environmental consequences, by way of
developing location-arrival time and location-quantity distributions. In
an example the flow system kinematics provide the geometry of flow in the
subsurface flow. The paths of flow are needed for individual particles
moving through the flow system to the points of emergence at the outflow
boundaries. The paths of flow and the arrival time at outflow boundaries
are determined by the path lines. The differential equations for the
path lines are referenced by the author to his publications submitted for
publication to Water Resources Research. January 1975. (As of the August
1976 issue, these referenced papers have not been published.)
One gets the feeling that the author glosses over the difficulty
with transport analysis. Bredehoeft and Finder (Water Resources Research
[1973] p. 194 — not referenced) do a better job. Little is said about
chemical reactions in transport.
The author did not appear and there was no discussion
-32-
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A. 2 Paper No. 17
A pilot plant was used for artificial recharge to investigate
the evolution of various pollutants in the basin and subsequent ground
layers. The following compounds were introduced separately:
1 mg/Ji Pb N03
1 mg/Ji Na alkyl aryl sulfonate
2 mg/s. a synthetic alcohol (nonionic)
2.5 mg/Jl phenol
12.5 mg/£ hydrocarbons and surfactants (soluble oil)
300 mg/£ refinery effluent
1 yg/2, lindane
10 vg/a lindane
Algal and bacterial counts were made in the basin water and in
the sand before and after passage of the flows. The sequence of flow after
the basin was 10 on washed sand, 2.8 m raw sand, 10 cm gravel, 2 m ground
chalk and 2 m large pieces crushed chalk.
The lead never penetrated to the raw sand, and precipitated
largely in the basin above the washed sand due to the high alkalinity
(level never mentioned). The detergents, hydrocarbons and phenols pene-
trated only during the first hours until the bacteria could adapt to the
compound used. This suggests that even if higher levels were introduced
it is only a matter of time before natural microorganisms will eventually
clear up the contaminant, if degradable.
A.3 Paper No. 20
This is a case history of groundwater contamination. Although
there are many similar cases in severity and complexity, the efforts made
by the author were interesting and commendable. It was rather confusing
to the reader and to the listener because the map and figures did not
locate many of the reference points, i.e., West Footscray, Stonycreek,
the chemical plant, the new treatment plant, the vertical scale in Fig. 2,
the Maribyrnona and Werribee rivers. The 90° orientation of the geologic
cross sections could probably not be helped, but added to the confusion.
It was interesting to see the apparent solution of the phenol and oil
problem by utilizing the microorganisms beneath the oil layer by using
the discharge-recharge jet flow with the jets located beneath the oil
layer. It was also interesting to see that a major mineral degradation
in the upper aquifer from the north-northeast resulted from the cone
developed at 248, and a lesser plum in the lower aquifer in 1975 from the
southeast. This contamination may likely rival the contamination from
the north-northeast in time.
-33-
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B & C Discussions
B & C.2 The prepared discussion of Paper No. 17 concerned buffered
water in relation to lead precipitation and something about Australian
experiences with contamination with zinc.
A question from the floor pertained to replacement of the succes-
sive ground layers between the periods of application of contaminants to
which the answer was no. The basins were cleaned with the use of large
volumes of water in the intermediate periods.
B & C.3 The prepared discussion and that from the floor (Paper No. 20)
pleaded for models for waste disposal control, and suggested desalting
brackish water rather than steps to prevent neighboring contamination,
the possibility of storage and disposal elsewhere.
D. Other Observations and Comments
D.2 On reflection, it seems to me that this pilot plant investigation
should be labeled as an artificial, artificial recharge study, and could
better be studied on a 20-year full scale on-going recharge operation such
as that using the Illinois River water at Peoria, Illinois. With the
current analytical instrumentation capabilities, there is a builtin oppor-
tunity to gather some very important data.
D.3 It appears from a National Geographic Atlas that Footscray is a
suburb adjacent west of Melbourne and north of Williamstown on the bay,
with little open land between. It is probable that no real assessment of
the source of mineralization from the northeast and from the southeast can
be made. Therefore recharge from new treatment plant facilities may
eventually augment rainfall to raise the water level in the local aquifer
and reduce the trend of heavy mineralization in time.
IV. CRITIQUE OF SESSION
This was one of the first sessions of the meeting and the
Chairman conscientiously adhered to the schedule, and clearly explained
and maintained the rules of procedure, with no problems. The prepared
discussions were complimentary and recognized the problems of fulfilling
perfection with the limited time for presentation. The questions (and
suggestions) were courteous and the speakers responded graciously. The
authors for both papers (17 and 20) could have used more than the restricted
10 minutes to make the printed paper more clear and avoid some of the
questions. Paper 17 received many questions to the end of his period,
and Paper 20 was clearly confusing in some aspects from my standpoint,
but his responses to the questions were generally to the point. It was
a difficult presentation. The research was conducted carefully for both
papers and no unreasonable claims were cited.
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V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
My opinion on significance and value are expressed in the
Review of Sessions under III D.
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I. SESSION
A.
B.
Theme of Session: Chiorination, Flocculation and Adsorption
Papers Presented: 3.
6.
Comparative Evaluation of Commercial
Polyelectrolytes for Flocculating Alum
Precipitated Domestic Wastewater.
A. Benedek, J. L. Bancsi (Canada)
Treatment of Chlorinated Hydrocarbons
Wastewater by Activated Carbon Absorption
with Steam Regeneration.
Y. Argaman, G. M. Sassu (Israel)
A Fundamental Study of the Removal of
Polynuclear Aromatic Hydrocarbons from
Water During Chiorination.
R. Perry, R. M. Harrison (Great Britain)
12. Chromium Removal with Activated Carbon.
J. I. Kim, J. Zoltek, Jr. (USA)
9.
II. REVIEWER
A. Name: John P. Giesy, Jr.
B. Position and Affiliation: Research Associate, Savannah River
Ecology Laboratory
Assistant Professor, Dept. of Zoology
University of Georgia
Athens, Georgia 30601
III. REVIEW OF SESSION
A. Formal Papers
All four of the papers presented in this session represented
advances in removing undesirable nutrients or contaminants from waste-
water. While none of the papers represented astounding scientific or
engineering breakthroughs or new theory, each presented the type of
pragmatic information needed to improve water treatment at the treatment
plant level.
A.I Paper No. 3
The manuscript presented flocculation properties of commercially
available polyacrylanndes indicating the optimum chain length and percent
hydrolysis. The authors appraised the relative gains due to reduced
flocculation time.
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A.2 Paper No. 6
This manuscript did not present a new method for removing
chlorinated hydrocarbons from water or a new method of regeneration but
did report the effectiveness of these techniques on a process scale.
The use of steam generation instead of thermal regeneration resulted in
water of the desired quality at lower cost.
A.3 Paper No. 9
This was the most theoretical of the four papers presented in
this session. The primary objectives of the work presented were the
development of sample preparation and detection techniques for the
determination of polynuclear aromatic hydrocarbons (PAH). The authors
cautioned that many factors, which are not generally considered, may
affect analytical results. The title of this paper is misleading because
little material on removal by chlorination was presented in the oral
presentation. The manuscript does present data on the kinetics of PAH
removal from water by chlorination and the effect of pH and dissolved
solids on removal.
A.4 Paper No. 12
This manuscript presented theoretical information on the adsorp-
tion properties of chromium on activated carbon. Optimum conditions for
Cr adsorption were reported to be the proton (H+) to Cr+6 ratio.
B, C & D. Discussions
B.I Most of the prepared and floor discussion of Paper No. 3 centered
around the relatively small economic gains and overall water quality improve-
ment due to polyacrylamides polyelectrolyte (RAPE) flocculants. The authors
addressed these questions by indicating that the most significant gains
achieved by PAPE usage would be in the case of overloaded clarifiers where
the volume of water processed could be increased while maintaining pre-
scribed P04 levels in the untreated water. Another concern of the desig-
nated discusser and floor discussers concerned the possible toxicity of
PAPE. The author cited several studies which demonstrated that PAPE in
current use were not acutely toxic to fish but was unable to field questions
on possible carcinogenic properties of these polyacrylamine compounds.
B.2 The designated discussers presented several good points about
Paper No. 6. The main concerns were with activated carbon regeneration
such as: Do mixtures of organics act similarly to pure compounds? What
happens to nonvolatile compounds such as high molecular weight oils which
may saturate the carbon and not be regenerated by steam? How can break-
through of columns be controlled? How many cycles of regeneration can be
used?
The author addressed all questions from the designated discusser
and the floor well. The author indicated that the columns must be set up
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in a series of three columns with two in the scavenging cycle while the
third is being regenerated. The activated charcoal, in the applied situ-
ation presented in this paper, can be used for about 10 regeneration
cycles before it must be thermally regenerated.
I feel that technology of this type presently has a number of
shortcomings, especially for treating complex organic wastes. The water
quality of the effluent water reported in this study was 1 mg/£ of
polyvinyl chloride. While this is a considerable improvement over raw
effluent, work here in the United States has indicated that we should be
concerned with \*g/i and ng/£ levels of synthetic organics in the environ-
ment. Another problem with the activated charcoal treatment as practiced
is the atmospheric release of organics upon regeneration.
B.3 The designated discusser of this paper did not address the
material presented but presented a review of another research program
studying PAH breakdown by ultraviolet light. This review indicated that
sunlight can cause considerable decomposition of PAH compounds.
Those in attendance at the session were in agreement that the
UV decomposition studies were not applicable to natural systems because
of variation of PH and total dissolved solids and because the study used
detergents and acetone to dissolve the PAH compounds.
Discussion of the manuscript from the floor centered around the
importance of studying low levels of PAH compounds in water supplies
because they are present at low levels, difficult to detect and very
diverse. The author pointed out several studies which had indicated the
carcinogenic nature of these compounds at very low levels. Several
members of the audience asked what the products of chlorination of PAH
compounds might be and whether they might be more carcinogenic than PAH's
alone.
B.4 The prepared discussion of this manuscript was the most penetrat-
ing discussion given during this session. While most of the floor partici-
pants thought the results were interesting, they did not feel that they
represented significant advancements in water treatment because of the
high cost and near impossibility of controlling the H+:Cr+6 ratio on a
process scale.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Using the information presented by the authors of Paper No. 3,
individual plant operators can calculate the relative cost versus water
volume or retention time costs. The authors conclude that in many routine
plant operations, polyelectrolyte flocculants may not improve flocculation
over that of alum alone. However, if plant capacity is limited, as is
often the case, the use of acrylic polyelectrolytes may increase processing
capacity by as much as 400 gal/day/sq ft.
Manuscript No. 6 may be useful for some industrial water treatments,
The most interesting discussion of this paper was by people attending the
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session who thought that activated charcoal may be useful in treating
drinking water for the removal of synthetic organics.
Many workers in the United States have been concerned with the
detection and identification of PAH compounds in drinking water. Manu-
script No. 9 supplies valuable information on the detection and identi-
fication of PAH compounds and some insight on their behavior when drinking
water is chlorinated.
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I. SESSION
A. Theme of Session; Coastal Pollution
B. Papers Presented: 15. Sedimentation of Dispersed Oil in Surface
Waters.
M. Thuer, W, Stumm (Switzerland)
18. The Application of a Two-layer Time-Dependent
Model to Pollution Assessment and Control
in a Short Stratified Estuary.
R. M. Pitblado, R. 6. H. Prince (Australia)
21. Preliminary Design of Ocean Outfall at
Sydney: Protection of Bathing Waters.
I. G. Wallis, T. J. Pollock, M. W. Whyte
(Australia)
II. REVIEWER
A. Name: R. E. Speece
B. Position and Affiliation: Betz Chair Professor of Environmental
Engineering
Drexel University
Philadelphia, Pennsylvania 19104
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 15
The intent of the first paper was to cover:
1. Transport mechanism of oil in natural waters
2. Mechanism whereby spilled oil is dispersed
3. Model colloid - chemical interaction and fate
This topic is extremely relevant to U.S. and global interests. Even
though the public press focuses attention on the more dramatic oil spills
that occur at sea, the less dramatic, day by day addition of oil to inland
waters impacts the lives of the U.S. populace to a much greater extent.
The relative contribution of oil to the hydrosphere by storm water over-
flows and sewage treatment plants is much greater than the contribution
to the hydrosphere by spills. This underscores the importance of storm
water management and unit process des'ign for removal of dispersed oil.
Industrial waste codes for management of effluents from automobile service
stations and repair garages commonly prescribe treatment by gravity
removal and skimming is relatively ineffective.
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An understanding of the fate and transport of oil in the hydro-
sphere is crucial. A complex series of interactions occurs once the oil
reaches the hydrosphere. Were it not for these complex interactions,
all of the oil would rise to the surface and eventually be deposited at
the land-water interface. However, the interaction of the dispersed oil
with particulates carried in the natural waters results in a combined
density greater than water. This in turn transports the oil to the sediments.
About 10 percent of the oil introduced into the hydrosphere is
eventually transported to the sediments in the vicinity of industrialized
regions. Great ecological change is created by the oil in the sediments.
In aerobic environments, microbial degradation of the oil occurs. Thus,
the oil in the sediment encourages the persistence of anaerobic conditions.
The anaerobic conditions in turn create an environment whereby precipitated
phosphorus can be solubilized and fed back into the overlying water. The
end result is that eutrophication can be encouraged.
Fortunately microbial conversion of the oil to carbon dioxide
plays a dominant role in the overall picture, destroying approximately
90 percent of the oil entering the hydrosphere. Aerobic conditions are
obligatory for microbial oxidation of the oil - the accumulation of
natural oil deposits over eons of time attests to their resistance to
anaerobic conversion. It is extremely important to recognize that micro-
bial oxidation of the oil must occur in the aqueous phase. This points
out the dominant role of extra cellular enzymes to solubilize the oil
before it can pass through the bacterial cell wall for oxidation. A
vivid demonstration of the dominant role of microbial destruction of oil
is found in the relatively rapid destruction of tar balls on sandy beaches.
The moist environment allows bacteria to proliferate on the surface of
the tar balls and exposure to the air maintains an aerobic environment.
The low temperatures prevailing in sediments also retard microbial degra-
dation even if aerobic conditions prevailed. In some aqueous environs,
microbial degradation may be retarded due to the lack of an adequate
nitrogen source to sustain microbial synthesis.
The atmospheric "rain out" of evaporated hydrocarbons may be a
significant pathway to the hydrosphere. However, the lower molecular
weight of the fraction lends itself to a much higher rate of biodegradabil-
ity, which reduces considerably the environmental impact thereof.
The behavior of oil reaching saline, coastal waters was noted
to be significantly different than in fresh water - with respect to the
coagulation phenomena. The biodegradability phenomenon would not be
significantly altered.
The gas chromatographic techniques developed by Blumer at Woods Hole
have enabled specific identification of oil types - even to the extent
of identifying the specific well source.
There was some controversial discussion regarding the estimated
quantities of oil reaching the hydrosphere. An M.I.T. study reported oil
losses at 0.1 to 0.5 percent of the total oil transported. Using an esti-
mated value of 0.2 percent would yield about 2,500,000 tons per year to
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the hydrosphere. Professor Pearson of the University of California
stated that the M.I.T. estimate of total losses to the hydrosphere is
only about 20 percent of the actual losses. Professor Pearson also
confirmed that the relative contribution of oil spills to the hydro-
sphere was minor. He estimated 8,700,000 tons per year was in flux in
the hydrosphere. The oil flux into Santa Monica Bay from sewers dis-
charging therein would account for 1 percent of the world flux - using
the loss rate of 0.2 percent of oil in transit. The same would also be
true of the Danube River.
A.2 Paper No. 18
The discussion of the two-layer estuary model emphasized that
storm runoff was a much more significant contribution than industrial
wastewaters. The lower density of the polluted fresh water flowing into
the estuary results in most of the BOD remaining in the top layer of the
stratified estuary.
A.3 Paper No. 21
The subject of ocean outfalls for wastewater is of considerable
technical, political and economic interest. The major obstacle appears
to be public acceptance. Techniques for construction of long outfalls
were not available until recently. Consequently, the adverse public
acceptance of ocean outfalls was generated from experience with short
outfalls. In the public's mind, that distinction is not clear.
The bacterial die-off is closely related to the diurnal cycle.
Fecal coliform die-off tests showed that the time for 90 percent mortality
varied from 1.9 hours in the light to 40 hours in the dark - with other-
conditions remaining constant. Consequently, the effluent field reaching
the shore could be expected to be higher in the morning. Solar variation
between summer and winter should be considered. Bacterial standards are
normally lower in winter than in summer due to the absence of bathing
activity in winter. Initial dilution in the vicinity of the diffuser is
normally designed for 400 to 1 dilution.
IV. CRITIQUE OF SESSION
This session on oil in the hydrosphere was quite well received
because of the timeliness and pertinence of the subject matter. Oil in
the hydrosphere is of intense interest globally. It was quite relevant
to quantify the source contribution of oil into the hydrosphere and to
note that spills may be of major consequence locally but relatively minor
in the long run, overall picture. The need to address the oil contribu-
tion from point source sewers was perhaps the most important issue raised.
The session on ocean outfalls was very well received at the
conference. The audience had a great concentration of people who were
closely associated with actual design and monitoring of ocean outfalls.
It was suggested that the dilution and convection models could and should
be much simplified.
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V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Regarding oil in the hydrosphere a major effort should be made
to develop effective unit processes adaptable to effluents from automobile
service stations and repair garages for coalescence filtration. The field
operational costs associated with such equipment need to be evaluated to
establish the economic impact of such industrial waste treatment codes.
Likewise, microbial removal of emulsified oil by secondary treatment
processes for municipalities treating wastewaters of domestic-industrial
origin needs quantification to establish a national budget for oil con-
tribution to the hydrosphere by sewage treatment effluents.
Concerning estuaries there are many estuaries in the U.S. that
would fall into the category of "two-layered." The contribution of
pollution from storm events to the surface layer results in relatively
short term oxygen depletion. The stagnant bottom layer of the estuary
eventually receives the burden of the pollution and often undergoes
extended periods of anaerobiosis as a result. Fish life is not possible.
It was quite pointedly demonstrated that agreement between
observed and predicted parameters in a model is no guarantee of the value
of the model as conditions change. Likewise with models which have so
many inputs - 22 in this case - it is possible to make anything fit the
model by adjusting the parameters.
Proper model calibration requires frequent sampling of the
entire water column. Helicopters facilitate such sampling.
Regarding ocean outfalls, experience at the Water Pollution
Research Laboratory in Stevenage, England, has demonstrated that a great
discrepancy consistently occurs between die-off tests in small containers
vs. in-situ tests. It is vitally important to utilize drogue floats in
determining the shoreward migration of the effluent field. It was pointed
out that beach bacterial counts are not dominated by the effect of sewage
outfalls. Rather, rivers, storm water and birds are the dominant bacterial
contributors.
One very significant point was made that primary sedimentation
should be eliminated prior to ocean outfall disposal. The operation of
primary sedimentation and resultant sludge disposal problems are not
warranted in view of the fact that inclusion of primary sedimentation is
not reflected in improved beach conditions. Studies in Britain with
properly defined long outfalls have shown that it is impossible to detect
sewage 400 meters from the outfall. In sewage with high grease content
primary sedimentation may still be important because of the likelihood
of grease balls accumulating on the shore.
It is sometimes stipulated in the design criteria that the plume
remain submerged 90 percent of the time. This may be a desirable objective,
but it is very difficult - if not impossible - to monitor such a standard.
The actual spacing of the diffuser ports is not critical. The
main criteria are the discharge per unit length of diffuser and adequate
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port diameter to prevent plugging. Minimum diffuser port diameter
recommended is 7 cm. In shallower depths than about 50 m, it would
be more important to insure higher velocity through the diffuser jets
to achieve higher immediate dilution ratios.
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I. SESSION
A. Theme of Session: Dynamics of Biological Nitrification
B. Papers Presented: 22. Dynamic Nature of Nitrifying Biological
Suspended Growth Systems
K. L. Murphy, P. M. Sutton, B. E. Jank
(Canada)
25. Design of Nitrifying Activated Sludge
Process with the Aid of Dynamic Simulation
W. Gujer (Switzerland)
II. REVIEWER
A. Name: John Cairns, Jr.
B. Position and Affiliation: University Distinguished Professor
Virginia Polytechnic Institute and
State University
Blacksburg, Virginia 24061
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 22
The main point was they found no distinct advantage of combined
over separate activated sludge systems. Apparently the model is not
generalizable.
A.2 Paper No. 25
The principal value of this paper is the detailed information
generated.
B. Prepared Discussions
B.I The discusser, A. Balaban (Israel) questioned some of the basic
data (particularly Table 3 in original paper). Otherwise Balaban's review
was perfunctory.
B.2 A. L. Downing (United Kingdom) gave a very favorable review but
indicated this was merely an update of some research carried out by Downing
and others at Stevenage (United Kingdom) some years ago.
C. Floor Discussions
C.I The most relevant floor discussion was initiated by Professor
Barnes of University Clyde, Glasgow (United Kingdom). Barnes pointed out
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that getting data good enough to handle by the transfer coefficient
equation would require sampling about every 10 minutes (or perhaps more
frequently). Paper No. 22 did not have short enough sampling intervals.
The question of substantial inhibition (50 percent reduction in growth
rate) was acknowledged. Sutton's reply to discussion was that they were
not trying to develop a universal model but rather to see how influent
variability affects function. This alone seriously limits the utility of
this presentation.
C.2 Sutton was the principal floor discusser - the nitrogen loss
really not accounted for, the model indicates it should reappear as
nitrate. Gujer did not disagree with these comments.
D. Other Observations and Comments
Even with many simplifying assumptions the nitrifying process
is still too complex and poorly understood to produce general models with
practical utility.
IV. CRITIQUE OF SESSION
No major conceptual breakthroughs (these are exceedingly rare)
but generally sound professional research that was mostly well received.
Research was original but some models may not be generalizable to other
situations.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Techniques and methodology were probably the most useful contri-
butions. Identification of trouble spots (i.e., data collected less
frequently than desirable) will help Americans avoid similar errors.
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I. SESSION
A. Theme of Session: General
B. Papers Presented: 28. An Integrated Pollution Control System:
Combined Clarification of Wastewater and
Incinerator Scrubber Effluent and Utilization
of Clarified Effluent for Scrubbing of
Stack Emissions.
W. J. Weber, Jr., F. L. Snitz (USA)
M. Rebhun (Israel)
31. Design Approach for Effluent Variability
Removal in Wastewater Treatment Systems.
V. Novotny (USA)
34. The Integration of Wastewater Treatment
with Water Reclamation.
L. R. J. VanVuuren, W. R. Ross, J. Prinsloo
(South Africa)
II. REVIEWER
A. Name: James H. Reynolds
B. Position and Affiliation: Assistant Professor, Civil and
Environmental Engineering
Utah Water Research Laboratory
Utah State University
Logan, Utah 84321
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 28
Two significant errors in the preprint of the paper were corrected
by the authors during their formal presentation of the paper. Figure 1 in
the original printed paper (which is incorrect) v/as identical to Figure 6.
Figure 1 of the printed paper should appear similar to Figure 1, Schematic
Diagram of an Integrated Pollution Control System, which is attached to this
review. The second correction pertains to Figure 4 in the original »paper.
The label for the upper right hand graph of Figure 4 should read "100 mg/£
Alum" instead of "10 mg/l Alum."
The paper is an excellent attempt at combining two separate waste
disposal units into one integrated system. This approach to integration
of waste disposal systems is a concept which has tremendous merit in nations
where waste disposal has reached crisis portions. This is especially true
in the United States. Although the particular system discussed in the
paper has several drawbacks, the basic concept of integration is farsighted.
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The importance of integrated waste disposal systems will become readily
apparent as the demand and shortage of our nation's energy resources
increase.
A.2 Paper No. 31
This paper described an innovative technique, based on the
frequency response approach, for determining the effluent variability of
a waste treatment process for a complete treatment plant. Although the
mathematical development of the paper is somewhat difficult to understand,
the approach for design of equalization basins has significant merit.
The author indicated in his formal oral presentation that this paper was
intended to be a conclusion of three previous papers published by the same
author (Novotny and Englande, Jr., 1974; Novotny, Englande, Jr. and
Mojgani, 1976; Novotny and Stein, 1976). Individuals particularly inter-
ested in the subject should review the previous publications carefully.
The author indicated that there were three errors in the preprint
of the paper. Therefore, the following corrections should be noted:
1) Figures 4 and 7 of the original paper should be interchanged.
2) The title of Figure 5 (original paper) should read:
"Variability reduction of a random input to a dispersed
flow tank."
3) Equation 7 should read:
PQ 5
A(F) = exp {^ {1 - (a^ + b£)"4 cos a}}
A.3 Paper No. 34
The paper presents the results of a pilot scale study designed
to investigate wastewater reclamation for reuse. The pilot plant can be
operated as an independent physical-chemical plant or in conjunction with
biological process units. The preprint of the paper presented the results
of five different operational modes studied using this particular pilot
plant. During the formal presentation of the paper, the author discussed
a sixth operational mode which was not included in the preprint. The
sixth mode is outlined in Figure 2 which is attached to this report.
No specific data were presented concerning the performance of
Mode VI. However, the authors indicated that it was a highly promising
approach and that a full scale report of Mode VI would be published in
the near future.
The authors indicated that their primary purpose in the study
was to produce a water suitable for unlimited reuse. Their principal
reuse parameter was a nitrate-nitrogen level of less than 10 mg/£.
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Several of their modes of operation achieved the 10 mg/£ nitrate-nitrogen
level. However, in all cases the COD concentrations were greater than
40 mg/£. As noted by several discussers of the paper, this high level of
COD indicates that there exists a high potential for refractory organics
to remain in this water which is intended for unlimited reuse. This will
be discussed in more detail in the discussion portion of this review.
This paper reported the successful operation of the dem'trification
process without an external carbon source. Instead a portion of the raw
waste was cycled directly to the denitrification unit, thus providing the
needed carbon.
B. Prepared Discussions
B.I The formal discusser of the paper raised several interesting
questions with regard to the research, (i) What chemical dosages would
be required? (ii) Is there a potential buildup of heavy metals in the
system which could be harmful? (iii) Would there be problems of locating
the wastewater treatment plant near the incinerator and vice versa?
The authors responded that (i) chemical dosages would have to be
determined on a case by case basis. However, their data indicated a
broad range of chemical dosages was acceptable, (ii) Heavy metal buildup
could be a problem. However, lime coagulation could solve the problem.
(iii) Site selection would require an economic evaluation on a case by
case basis.
B.2 The prepared discussion (Paper No. 31) was relatively brief.
The discusser suggested at least two other methods for flow equalization.
These were (i) control of infiltration and inflow, and (ii) pretreatment
of industrial waste. The discusser felt that these methods had been used
satisfactorily in the past and inquired if the new approach presented in
the paper had been demonstrated on a "real world" system. The discusser
also inquired as to the significance of the new approach since the example
presented in the paper only reduced the detention time calculated by a
standard safety factor method by only 6.7 percent.
The author of the paper responded that this paper was the con-
clusion in a series of four papers and that applications to at least
laboratory scale treatment processes were presented in the previous papers
(Novotny and Englande, Jr., 1974; Novotny, Englande, Jr. and Mojgani, 1976;
Novotny and Stein, 1976). The author also commented that it was only
coincidental that the example presented in the paper resulted in a 6.7
percent reduction. For systems with high variability this new approach
would be much more reliable than employing an empirical safety factor.
B.3 The formal discusser indicated that the demonstration of the
denitrification process without an external carbon source was very inter-
esting. The formal discusser indicated that a denitrification plant
employing methanol as the external carbon source was in preparation near
Camberra, Australia. The calculated daily methanol requirement for that
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plant alone would exceed the total amount of methanol currently imported
into Australia.
It would appear that at a time when the cost of petroleum
products is extremely high, non-external carbon source denitrification
systems should be more fully demonstrated.
C. Floor Discussions
C.I The floor discussion (Paper No. 28) centered around the portion
of the paper which indicated that coagulation-clarification could be
accomplished with fly ash only. This aspect will be discussed in detail
in the Other Observations section of this report. Most discussers were
favorable to the research.
C.2 No comments or other discussion from the floor occurred with
respect to Paper No. 31.
C.3 The floor discussion (Paper No. 34) centered more on the issue
of reuse in general rather than a direct discussion of the material presented
in the paper. The discussion was dominated by delegates from water-short
countries such as Israel, South Africa and Australia.
There was considerable discussion concerning the acceptable level
of nitrate-nitrogen in the reclaimed water. The authors were holding to a
10 mg/£ nitrate-nitrogen level. However, several discussers reported on
specific cases where people had been drinking water with extremely high
nitrate levels without any harmful effects. For instance, a community in
Yemen has been using water with nitrate-nitrogen levels ranging from
200-300 mg/£ with no harmful effects. An Australian family has a private
water source with nitrate-nitrogen levels ranging from 100-150 mg/£. The
family has utilized the water for three generations without any harmful effects,
The high COD levels of the proposed reuse water was of concern
to several discussers. High COD levels indicate a high concentration of
dissolved refractory organics which are potentially harmful. More research
is needed to develop processes which will reduce these substances to safe
levels. One discusser reported that in a survey conducted in the United
States, within waters with a TOC of from 3-5 mg/£, approximately 250 dif-
ferent organic compounds were identified. The health risks relating to
these compounds are not presently fully known.
D. Other Observations and Comments
D.I The need for the integrated system was expressed by several
members of the audience. Four Australian and two South African Conference
participants expressed keen interest in the system.
The portion of the paper which gained the greatest attention was
the data indicating that municipal wastewater could be successfully coagu-
lated and clarified without chemical addition, i.e., lime or alum, provided
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sufficient fly ash was present in the scrubber effluent (Figure 6 of original
paper, Weber e£ al., 1977). These data suggested that a substantial savings
in chemical costs could be achieved through the integrated approach. How-
ever, using fly ash to attempt wastewater coagulation-clarification without
additional chemical addition has two potential problems. The first concerns
the degree of control and flexibility available to the treatment plant operator.
That is, from a practical point of view, it appears that it would be an
extremely difficult task to match the scrubber effluent fly ash concentration
to the required municipal wastewater coagulant dose.
The second potential problem concerns the availability of sufficient
quantities of fly ash to actually coagulate the wastewater. For example,
according to the authors 1 to 4 g/l of fly ash is required to achieve adequate
municipal wastewater coagulation-clarification. The authors also indicate
that a community of 200,000 people would require a scrubber which would pro-
duce a maximum effluent of 26,495 m3/day (7 mgd). This same community would
generate approximately 75,700 m3/day (20 mgd) of municipal sewage. The fly
ash dose required to successfully coagulate and clarify this amount of munici-
pal wastewater would range from 74.6 metric tons/day to 302.6 metric tons/day
(83.4 short tons/day to 333.6 short tons/day). This would mean that the fly
ash concentration of the scrubber effluent would have to range from 2,857
mg/£ to 11,428 mg/l. These required concentrations of fly ash seem rather
unrealistic. One conference participant from Australia estimated that 300
to 500 metric tons of fly ash/day would be required to treat the municipal
sewage of Sydney.
Although the total dependency on fly ash for coagulation-clarification
does not seem feasible, it does appear from the authors' data that a potential
savings in chemical costs is possible.
There was some concern expressed concerning the release of heavy
metals (Cu, Pb, Zn, Mg, etc.) by the fly ash when the scrubber water was
integrated with municipal wastewater. However, the authors provided data
indicating this was not a serious concern. A comparison between the authors'
data and Water Quality Criteria (EPA, 1972) indicates heavy metals should
not be a threat to the system unless buildup occurs due to the continual
recycle of the water. The authors did not have enough data to indicate the
significance or nonsignificance of heavy metal buildup.
D.2 The technique presented in this paper (No. 31) appears to be
very innovative. It allows the design of plant performance to be based on
statistical variation. That is, instead of plants being designed to meet
an absolute mean effluent value, the treatment capability of the plant is
designed on the degree of statistical confidence the design engineer wishes
to select. For example, instead of designing a plant to discharge only
30 mg/£ BODs under all conditions, the design engineer can design the plant
on a 95 percent probability that the effluent BODs concentration will not
exceed 30 mg/l. This latter approach allows designers to reflect what
actually occurs in nature rather than fitting the design to an arbitrary
standard.
D.3 Discussion of Paper No. 34 after the formal presentation indicated
that the most probable reason for the lack of harmful effects due to the
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high nitrate-nitrogen in the water in both the Yemen and Australian cases
is that infants were not drinking the water directly. In both cases, it
was speculated that infants were being breast fed and thus were not directly
exposed to drinking the water.
IV. CRITIQUE OF SESSION
The paper by Weber
-------
reuse, the need for better methods of detection and removal of refractory
organics becomes more urgent. This paper illustrates that water for reuse
can be produced but that the health risk of the dissolved organics must
be considered.
REFERENCES
Environmental Protection Agency, "Water Quality Criteria," EPA-R3-73-033,
U.S. Government Printing Office, Washington, D.C. (1972).
Novotny, V. and Englande, A. J., Jr., "Equalization Design Techniques for
Conservative Substances in Wastewater Treatment Systems," \tiaWi ReA.,
8, 325-332 (1974).
Novotny, V. and Stein, R. M. , "Equalization of Time Variable Waste Loads,"
JouA. EnviAon. Engi. flu;., ASCE, EE3, 613-625 (1976).
Novotny, V., Englande, A. J., Jr. and Mojgani, P., "Effluent Variability
Estimation for Complete-Mix Activated Sludge Treatment Systems,"
., 70, 699-709 (1976).
Weber, W. J., Snitz, F. L. and Rebhun, M., "An Integrated Pollution Control
System: Combined Clarification of Wastewater and Incinerator Scrubber
Effluent and Utilization of Clarified Effluent for Scrubbing of Stack
Emissions," P^tog. WoxteA Tech., 9, 365-380 (1977).
-53-
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I
en
Wastewater (Screened and Degritted)
Wet
Scrubber
Solid
Waste
Scrubber Effluent
Incinerator
Stack
Emissions
Incinerator
Settled Sludge
Incinerator Residue
Recycled Clarified Wastewater to Scrubber
Chemical
Addition
Additional
Biological
or
Physical-
Chemical
Treatment
Final
Effluent
Figure 1. Schematic diagram of an integrated pollution control system. (After Weber, Snitz, and Rebhun,
1977) omitted from original paper.
-------
Influent
Lime
Treatment
Effluent
Figure 2. Mode VI: LFB process without ammonia stripping
-55-
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I. SESSION
A. Theme of Session: Ultimate Disposal of Sludges, Toxic Wastes,
and Strong Organic Liquors - Impact of Various
Sludge Disposal Alternatives on the Environment
B. Papers Presented: Workshop - Ultimate Disposal of Sludges, Toxic
Wastes and Strong Organic Liquors.
Convener: G. E. Eden
Speakers: L. Ulmgren (Sweden), G. A. Carthew
(Australia), and B. Lynam (USA)
II. REVIEWER
A. Name: Davis L. Ford
B. Position and Affiliation: Senior Vice President
Engineering-Science, Inc.
Austin, Texas
III. REVIEW OF SESSION
A. Formal Papers
A.I B. Lynam of the U.S. presented a paper in the convened workshop
dealing with the various aspects of ultimate sludge disposal practiced by
the Chicago Metropolitan Sanitary District in Fulton County. He first
discussed a sludge reclamation which should be practiced when beneficial
use is a possible resultant. He cited the application of heat-treated
sludge to citrus and cotton areas in the state of Florida, natural gas
being used for heat treating the sludge which was subsequently dewatered
on vacuum filters with chemical conditioning. The storing and recovery
of dried sludge was cited, the sludge being stored for years in deep
quarries with water monitoring systems for both surface runoff and ground
water. Monitoring of methane gas was also involved. The long-term
storage made the sludge more acceptable, as there was complete destruction
of pathogens during the freeze and thaw cycles. The liquid sludge was
applied to the land by vehicles, and the public acceptance of this overall
disposal technique was underscored. The monitoring of the heavy metal con-
tent in sludges was also mentioned. The speaker cited the fact that corn
has been produced using these sludges as fertilizer and sold on the open
market, as well as soybeans, wheat and other feed grains.
A.2 L. Ulmgren of Sweden also discussed the land application of
sludges. He indicated that municipal and industrial waste sludges were
often treated jointly with positive results. The metal processing indus-
trial sludges cause various problems and pretreatment was required to
facilitate sludge disposal. Temporary storage of sludge inventories during
the winter months was required because of the frozen ground and the sludge
could not be applied during this period. He indicated that as no ocean
disposal was permitted, the industrial sludges were conditioned with lime
and stored or disposed jointly with municipal refuse. The municipality is
responsible for disposal of these sludges when combined with refuse and
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the limit of application is one metric ton per hectare per year with the
possibility of every five years applying as much as five metric tons per
hectare per year.
A.3 G. A. Carthew of Australia discussed lime recovery via recalci-
nation of sludges generated from the lime precipitation of raw sewage.
This sludge is dewatered via centrifugation and burned in a multiple-hearth
furnace. The centrifuged solids capture rate was 35 to 60 percent, but
decreased with time resulting from abrasion and wear on the scroll unit.
It was indicated that the recycled lime from this recalcination process
produced better phosphorus and BOD removal in the primary units as com-
pared to the use of virgin lime.
B. Floor Discussions
There were several discussions from the floor during the workshop
session. Balitho from South Africa cited South African experience in land
disposal indicating that this practice had been followed for 60 years near
Johannesburg. He stated that the disposability of sludge was highly related
to the antecedent processes, citing for example that the maintenance of
sludge under aerobic conditions at all times minimized subsequent phosphorus
release. He also stated, for example, that high ammonia levels in the
sludge may overload the nitrification capacity of the soil, resulting in
chlorosis in plants. Approximately 7000 to 8000 animals in a test popula-
tion under close veterinary control were grazing on the land to which the
sludge was applied. He cited that the ascaris is not carried through the
plants to humans as the crops go to silage or feed for the cattle. He
further stated that inactivation of the ascaris with Cobalt 60 is complete
at a cost of $3/ton.
D. Cohen of Canada presented the next discussion from the floor.
He cited the sources of industrial sludges in Canada which include those
from the production of pulp and paper, textiles, petroleum, mining, organic
chemicals, and inorganic chemicals. He indicated several instances where
waste sludges were used for fuel without adverse effects on equipment.
A representative of Lurgi (Australia) discussed incineration of
waste chemical sludges and the energy conservation realized by the use of
these sludges. He also discussed the incineration of chlorinated hydrocar-
bons at high temperatures, high moisture contents and low oxygen levels.
The application of industrial sludges on sand dunes was also discussed
including the monitoring techniques used in detecting impurities in the
ground water which pick up the leachate. Submersible pumps were lowered
into bore hole's to enable sampling in single holes.
C. Responses and Other Observations
Ulmgren of Sweden indicated that the uptake of heavy metals in
plants had been reviewed for several years in Upsalla, Sweden; however,
there are no published data at this time. Lynam of the USA discussed the
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current restrictions of applying sewage sludge for land application because
there are no universally accepted values for all types of sludges and
soils. He indicated that the limitations for sludge application of land
are specific for the particular site and the characteristics of the sludge.
The control of industrial wastes into sewers was mentioned, using industrial
waste ordinances and pretreatment requirements for control. He also alluded
to the fact that industrial waste sludge disposal problems were many,
including those associated with heat treatment, injection wells, leaching
from landfill sites and contaminating ground waters, and persistence of
conservative components of sludge in the environment.
IV. CRITIQUE OF SESSION
It is interesting to note that the thrust of the conversation of
both the papers and discussions in this session seemed to emphasize in one
form or another the land application of liquid sludge. The trend seems to
be away from ocean disposal, and the energy situation in many countries has
mitigated the attractiveness of incineration of sludges, particularly those
of low BTU value. There was emphasis throughout the discussion of the
uptake of certain conservative constituents such as heavy metals in forage
crops and feed grains which have been fertilized, by liquid sludge as well
as potential ground water contamination resulting from the land application
of waste sludges. There was obviously some overlap between this session
and that conducted on Thursday morning, October 21, entitled "Land Treatment."
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
As indicated in Section IV of this report, the emphasis of the
ultimate disposal of sludges appeared to be directed toward conventional
dewatering processes using heat treatment and/or chemicals and land appli-
cation. Although this is obviously prohibitive in many of the more densely
settled areas of the United States, it appears that an emphasis on research
activities could include the following directly and indirectly related topics:
1. To evaluate the efficacy of selected land disposal of both
municipal, industrial and municipal/industrial sludge blends,
particularly in land areas where the fertilizer value of the
sludge can be realized.
2. To develop a better understanding of the impact of antecedent
unit processes on the sludge characteristics and the implications
of these processes in removing nutrients prior to land application.
3. To develop a cost-effective evaluation of the various ultimate
disposal alternatives including land disposal following sludge
treatment and dewatering, ocean disposal, and the incineration
of sludges, possibly reclaiming given constituents in selected
cases.
4. To assess formulation of optimum solution regarding land farming
of sludges by maximizing the conditioning of sludge for adequate
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dewatering and handling while minimizing the ultimate impact of
the conditioners on the soil and crops.
5. To perform specific research studies in evaluating the effect of
heat treatment reaction temperature and retention time on spe-
cific resistance as well as the evaluation of other variables
which influence the dewaterability of sludges. This is particu-
larly important when realizing that the capital and operating
costs of the sludge handling facilities could constitute 30 to 40
percent of the total cost of the wastewater treatment facility.
6. To make comprehensive studies of the fate of enteric bacteria
and enteric viruses contained in sludge when applied to the land.
Additional studies are warranted in determining the survival of
pathogenic microorganisms in crops used both for human consump-
tion and as feed grains and forage for livestock.
7. To develop information tracing the uptake and removal of heavy
metals from sludges to various soil types and specified crops.
An attempt to quantify the profile of heavy metals transferred
to soil and various crops, establishing a mass balance if pos-
sible, would be helpful in establishing the basic information
to determine the overall impact of heavy metals contained in
land-applied sludges on the receiving environment.
8. To develop a comprehensive energy analysis of heat treating, of
dewatering, incinerating and reclaiming specific constituents
from both municipal and industrial sludges. This energy consump-
tion should be put in perspective of the overall energy require-
ments associated with both BPTCA and BAT levels of wastewater
treatment facilities.
9. To make an evaluation of the land application of liquid sludges
in terms of the soil classification and temperature impacts on
this form of sludge disposal. It is recognized that a good por-
tion of both municipal and industrial sludges are generated in
areas with sterile soils and/or severe climatic conditions. A
sludge quality-soil characteristic-soil temperature interrelationship
would be helpful in formulating decisions relative to the ultimate
disposal of sludges.
10. To consider more seriously not only the land application of liquid
sludge but also the application of partially treated wastewater,
particularly in the arid and semi-arid land areas of the United
States. Although this at first glance appears to be an antiquated
concept with public health hazards, this concept under proper
controls has potential merit in water-limited areas. Of particular
interest is the land application of untreated sewage and'industrial
waste at the Werribee Farm near Melbourne, Australia.
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These are some of the more prevalent areas of research which
were discussed at the Conference. Although it is recognized that some
of these topics have or are being investigated to some extent, a compre-
hensive review of the aforementioned topics in terms of establishing new
areas of research can be considered.
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I. SESSION
A. Theme of Session: Sludge Thickening and Dewatering
B. Papers Presented: 23. Continuous Thickening of Sludges.
P. Kos (USA)
II. REVIEWER
A. Name: E. Robert Baumann
B. Position and Affiliation: Professor of Civil Engineering
Iowa State University
Ames, Iowa 50010
III. REVIEW OF SESSION
A. Formal Paper
A.I Paper No. 23
Flocculent suspensions form three different zones in continuous
flow thickeners: a zone of clear liquid, a zone of sedimentation, and a
zone of thickening. Sludge entering a thickener is partially dispersed
in the sedimentation zone and flows as a density current in the lower part
of that zone. The solid phase of the sludge creates floes which settle
to the top of the thickening zone, lose their individual character, and
become part of the matrix of solids compressed by the pressure of the over-
lying solids. The water in the thickening zone must flow upward through
the matrix of solids — and through channels in it -- as the matrix is
compressed. Design of a thickener requires determination of thickener
cross sectional area for sedimentation. of the floes in concentrations up
to the boundary condition, i.e., the concentration of the floe in the
upper boundary of the thickening zone, and thickening the sludge in the
sludge compression or thickening zone. With wastewater treatment plant
flocculent suspensions, the area required for thickening controls the
thickener design. Unfortunately, Kos states, "there is not at the present
time a reliable simple test procedure for thickening zone area and depth
evaluation."
The action in the thickening zone is a consolidation process and
can be described by studying the filtration and deformation properties of
thickened materials. In other words, gravity thickening in the thickening
zone is a flow (filtration) of liquid through a deforming saturated floccu-
lent porous matrix. There are various theories which describe such liquid
flow through non-rigid or deformable media. Kos studied transport of mass
and momentum in porous media and concluded that, for gravity thickening,
the model of a media with point contacts between particles is applicable.
He developed two equations:
1. Conservation of mass principle for steady state thickening
_ Qu Cu
--
/„ „ x _ r _ n n\
(vs - Vn-^--^j] (1)
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where vs = average solid vertical velocity relative to tank
v» = average liquid vertical velocity
n = porosity
Qu = rate of underflow
Cu = underflow solids concentration
Cx = concentration at depth x
A = cross-sectional thickener area, and
(vs - v^)n = superficial settling velocity
2. Summation of force balances of solid and liquid phases
where 07 = total pressure
p = liquid phase pressure
g = acceleration of gravity
^
d^ = density of liquid
ds = density of solid
Integration of the second equation gives
d/ v
OT(X) = o(x) + p(x) = gxd£x + gx(l - /) /* c(x) dx (3)
The total pressure at depth x, OT(X), is the weight of overlying suspension
per unit of area. The effective pressure, a, is the fraction of total
pressure transmitted through particle contact. The liquid pressure, p,
consists of the hydrostatic pressure and the excess hydrostatic pressure
(p-pressure). Similarly, the ay-pressure can be defined as the total
minus hydrostatic pressure:
OT(X) = OT(X) - gxd^x (4)
Thus, the liquid force balance relates the liquid pressure gradient
(dp/dx) to the relative velocity of solid and liquid phase (vs - v^).
The simplest relationship is Darcy's law:
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(vs -
where \i = dynamic viscosity
k = intrinsic conductivity, k1 =
-r-
d£9x
where K = hydraulic conductivity
Hydraulic conductivity is a function of porosity, n, for compressible
materials. When this relationship does not hold, the flow is non-Darcian,
and the "filtration characteristics" K is a function of other parameters
like (vs - v.£) or different forms of dp/dx versus (vs - v/) relationships
are used. Only experimental work can show the kind of relationship existing
between the pressure gradient and relative velocity of solid-liquid phases
in thickening operations.
For a full description of the thickening model, we must have a
mathematical description of compressive behavior (deformation) of the solid
matrix in high concentrations. As in soil consolidation
dc = a da
where a is the modulus of linear compressibility;
a = a(c)
Again, the stress-strain relationship must be determined experimentally.
In order to determine the "filtration chracteristic" and the
"stress-strain" characteristics of thickening zone sludges, laboratory
tests must be made in a continuous-flow, steady-state thickener. During
steady-state, the solids concentrations and pressure distributions are
steady for relatively long time periods making it easy to take reliable
measurements which can be compared to computer simulated results. Steady-
state conditions are provided when:
1. The solids inflow equals solids leaving in the underflow and
the thickener overflow.
2. The interface between sedimentation and thickening zones does
not move.
3. The distribution of solids concentration with thickening zone
depth is stable.
Data were collected in a 29 cm ID column 253 cm long equipped with a center
inlet well and a bottom sludge rake. Water treatment plant sludge was used
to demonstrate the theory developed in the paper (36 mg/£ of alum, 10.5
mg/£ of powdered activated carbon used to treat surface water).
In the laboratory experiments, 12 different steady-state runs were
established, maintained for a few days to assure steady-state, and readings
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and sludge concentrations were measured twice. Readings consisted of:
1. Solids concentration profile with depth (100 m£ of sludge
withdrawn at depths 10 cm apart after all other readings
were made).
2. Excess hydrostatic pressure (p-pressure) profile with depth.
The excess hydrostatic pressure measurement was made using
piezometers connected to the settling column at various
depths. A "Statham" Low Pressure Accessory (SLPA) capable of
pressure measurement in the range of 0 to 0.1 psi was placed
a few mm below the water level in the settling column. The
pressure piezometers were connected to separation cells which
in turn were connected to the SLPA. The separation cells
kept column solids out of the tubes. The (p-pressure) at a
certain depth was obtained by connecting the SLPA to that
depth and reading the portion of the piezometric pressure
above datum. Then, the portion of the hydrostatic pressure
above datum was measured by connection of the reference port
with the SLPA. The reference port was located just below the
water level.
3. The oy-pressure profile. The measurement of the total minus
hydrostatic pressure, ay, was carried out using the same
arrangement as the (p-pressure) measurement. Experimentally,
the solid matrix can transmit an effective pressure only in
the range from 0 to 100 dynes/cm2 (0.0015 psi). The solid
structure is easily destroyed (mixing, vibrations, etc.).
Thus, with matrix destroyed, the pressure at a port is the
pressure of the whole column of suspension above that port —
or the total pressure.
Kos presented his data in "raw" form in two graphs (Figure 5
of original paper):
1. Height of thickening column, cm, vs. suspended solids concen-
tration, g/£.
o
2. Height of thickening column, cm, vs. pressure, dynes/cm .
The former graph showed the variation in thickened solids concentration
with depth for each of three steady-state runs. The latter graph showed
both the total pressure, 07, and excess hydrostatic (p-pressure) for each
of the same steady-state runs.
To evaluate the "filtration characteristics" of the sludge, Kos
calculated the superficial ve^city (Eq. 1) for various sludge concentra-
tions and plotted Figure 6 (original paper),
(vs - vjn, cm/sec vs. excess hydrostatic pressure drop, dynes/cm .
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(The water sludge data were non-linear; therefore, the sludge is non-Darcian.)
Two models were developed to express the filtration properties of the sludge:
1. (vs- v£)n=A'() (9)
where A' and B1 are filtration characteristics, dependent on sludge
concentration.
2. A "capillary tube model" (10), (11), (12)
The diameter of the "imaginary capillary tube" as a function of the shear
stress on the wall of the capillary tube was shown in Figure 7.
To obtain the sludge "consolidation" characteristics, values of
effective pressure, dynes/cmZ, obtained from all steady state conditions
were plotted against suspended solids concentrations, g/£ {Figure 8).
The following equation was used to represent the C-a relationship:
C - Cb + A a8 (13)
where A and B are constants.
The curve defined by this equation was fitted to the data in
Figure 8 to give the following equation:
C = 8.0 + 0.7645 a0'7578 (14)
where C is in g/£ and a is in dynes /cm . This equation says that the
varying structure of the flocculent porous medium is due to varying flow
conditions (represented by shear stress on the capillary wall). Thus,
consolidation of the porous media solid phase is a function of both the
shear stress on the wall of the imaginary capillary tubes and effective
compress ive pressure.
To apply theory to design, a computer program was written to
simulate continuous-flow gravity thickening. The simulated results can
be plotted to show:
depth of thickening zone, cm, vs. concentration of
thickened sludge, g/£. for any given level of tank
solids loadings, kg/m* hr (Figure 9)
The laboratory data upon which the computer simulation is based are
also plotted to demonstrate conformance of the simulation with the model.
The computer simulated data can, for the case of a fixed depth of
thickening zone, be adjusted to provide a plot of:
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suspended solids loading concentration, g/£, vs.
underflow solids concentration, g/£ (Figure 10}
This plot provides a record of the maximum solids loadings associated
with maintenance of a given underflow concentration.
It was concluded that sludge thickening occurs because the solid
phase in the form of a matrix is compressed by the1pressure of the over-
lying solids and the released water flows upward through the media and
channels in it. The process is a flow of liquid through a deformed satu-
rated media which has very specific filtration and deformation properties
which can be measured and used in thickener design.
B. Prepared Discussion
Y. Argaman (Israel) pointed out that sludge thickening is a
unit process that has wide applications in both water and wastewater
treatment applications. Although the cost of thickening is not very
significant in overall treatment costs, the success or failure of the
process has very significant effects on other treatment processes.
For example, activated sludge treatment secondary clarifiers which fail
in their thickening function cause failure in secondary biological treat-
ment.
Argaman congratulated the author on making a significant con-
tribution to thickener process understanding. Currently, laboratory
studies are made to determine the zone settling properties of a sludge
(settling velocity of the interface) from which a solids flux vs. under-
flow solids concentration curve similar to Kos1 Figure 10 are drawn.
While this empirical approach is adequate for design, the process is
handled as if it were a settling process. This is not, however, a settling
process and Kos' analysis provides more insight into what is actually
taking place. Unfortunately, Kos1 doctoral thesis was not available to
review in depth the basis for his mathematical models.
The Kos approach has several advantages which were not empha-
sized in the paper in that it allows a designer or plant operator to
predict the effects of thickener depth, solids loading variations, par-
ticle sizes, etc. on the process efficiency.
The Kos procedures have several distinct disadvantages as com-
pared to those of R. I. Dick:
1. The collection of the required data requires larger volumes of
sludge and requires that at least 6 to 8 different runs be made
over a steady-state period of several days (12-24 days total).
It is doubtful if pilot plant sludges would be available in
sufficient quantity or quality to complete the tests required
for plant design.
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2. The tests needed to generate Figure 9 - type curves (depth vs.
concentration of thickened sludge for various levels of solids
loading) are elaborate and not very practical.
3. There is need to extrapolate the curves using a rather involved
computer program.
The Kos approach represents a more scientific step in the right direction
in developing a more accurate mathematical model of the continuous-flow,
steady-state, gravity thickening process. Further studies are needed,
however, to make it practical. For example, studies of the variations in
the filtration-consolidation characteristics of full-scale plant sludges
and correlation with gravity thickener operation would be of value.
C. Floor Discussions
Dr. Eden (UK). The Kos studies should be expanded to correlate
the results of pilot plant tests with full scale tests. Knowing the depth
of thickening, is there a simplified design procedure that could be used
with Figure 9 based on solids retention time?
R. I. Dick (US). Dick commended the author and discussed briefly
the implications to design. The Coe-Clevenger-Kinch models are based on
solids concentrations below the zone settling interface. Dick questioned:
1) whether the traditional design approach would, as a practical matter,
be in error by ignoring the interparticle forces; and 2) what is the sig-
nificant limiting solids concentration?
Skinner (Australia). Skinner asked for an estimate of the
error possible in design using current thickener design methods.
Reply - The main result of the Kos paper should be to dismiss
once and for all time the myth that sludge thickening is a sedimentation
process. The rate-limiting process is filtration. The Kos method can
be used in thickener design, but lots of sludge is needed.
Fitch and Kos are about to publish an article on "How to Use
Batch Data to Generate Figure 10." The sludge thickening design approach
will appear soon in a Filtration/Separation (British) Review article.
There are no data in the lower region of Figure 6 since suspensions
cannot exist in that region.
Lines of equal detention time running from the right downward
to the left cutting the solids loading curves can be drawn in Figure 9.
Detention time, however, is of secondary significance because you cannot
design a thickener based on detention time. In Figure 5 the line with
the steepest solids concentration vs. depth line would provide the limit-
ing solids concentration.
It is hard to estimate errors in traditional thickener design
assuming the Kos approach provided accurate results. For flocculent solids,
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however, the estimated error in use of traditional methods would be up
to 200-300 percent, the result being underdesign. For mineral applica-
tions, traditional methods would result in thickener overdesign by 50 to
200 percent.
IV. CRITIQUE OF SESSION
Kos1 paper represents a new fundamental approach to thickener
design based on scientific principles. The thickening process is not a
sedimentation process even though current laboratory studies on which
thickener designs are based are conducted by measuring the sedimentation
rate of the interface at the top of the zone settling sludge layer. Kos
clearly demonstrated that the filtration and deformation properties of
sludge are critical in affecting sludge thickening. His data are convincing.
The paper does not detail in depth the development of the various
mathematical models used in the paper. The continuous-flow, steady-state
laboratory tests require large volumes of sludge and 10 to 15 days to com-
plete. Thus, use of the Kos model as presented in everyday thickener
design is impractical. No correlation of theoretical laboratory continuojs-
flow thickener results with plant scale results,were provided and, evidently,
have not yet been attempted. Kos did indicate that a paper describing how
to use "batch thickener" test data for design would be published shortly
in the Filtration/Separation Journal (Br.).
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
With the new requirements for water treatment and improved secon-
dary and tertiary wastewater treatment, the need for thickening larger
volumes of sludge is increasing. In activated sludge treatment, the fre-
quent failure of secondary clarifiers in providing a thickened sludge for
recycle has led to the use of flotation thickeners in place of gravity
thickeners.
The Kos paper has described a more fundamentally sound method
of collecting pilot plant (laboratory) data on which to base the design
of gravity thickeners. Further studies must be made to make the new
basis for design practical:
1. The laboratory tests must be refined to provide the required
design data with less sludge and in shorter time periods.
Batch test data may provide this possibility.
2. The design approach must be verified in plant scale evaluations
of the accuracy of the design approach. In fact, the approach
may be effective,when combined with computer extrapolation of
the data, in improving the operation of an existing thickener.
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I. SESSION
A. Theme of Session: Sludge Thickening and Dewatering
B. Paper Presented: 26. Dewatering Properties of Lime Stabilized
Sewage Sludges.
B. Paulsrud, A. S. Eikum (Norway)
II. REVIEWER
A. Name: E. Robert Baumann
B. Position and Affiliation: Professor of Civil Engineering
Iowa State University
Ames, Iowa 50010
III. REVIEW OF SESSION
A. Formal Paper
A.I Paper No. 26
Paulsrud presented the paper briefly. In Norway, raw primary
sewage in small plants is stored for extended periods before further
treatment or land disposal. Lime is frequently added to control odors
and to reduce anaerobic digestion. Since lime does not affect the organic
material but simply reduces biological action, it was deemed desirable to
conduct studies of the effect of storage time on the dewatering proper-
ties of lime-treated raw sludge.
Raw primary sludge (2 samples), mixed primary-chemical (alum)
sludge, mixed secondary-chemical (alum) sludge, and septic tank sludges
were treated with 0 to 600 g Ca(OH)2 per kg total suspended solids and
stored for periods of 0 to 28 days. Samples were removed at 0, 1, 4,
7, 14, 21, and 28 days to evaluate:
1. Changes in pH
2. Changes in sludge specific resistance
3. Changes in sludge drainability on a. small sand filter
4. Changes in sludge conditionability with a standard polymer
(Praestol 444K) as measured by the CST (capillary suction
time) test
The test results indicated that to preserve sludge drainability
characteristics, the sludge should retain a lime-induced pH greater than
11 for at least 14 days in an open beaker at 20°C. The lime dosage
required was as follows:
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Lime Dosage Required
Sludge g Ca(OH)2/kg TSS
Raw Primary 200
Mixed Primary-Chemical 300
Mixed Secondary-Chemical 400
Septic Tank 100
Initially the addition of lime reduced the specific resistance
of all sludges proportional to the lime dose. If the pH of the sludge
decreased with time due to biological action generated during storage,
the specific resistance of the sludge increased with time. If the pH did
not decrease below a pH of 11, the 0 time specific-sludge resistance was
maintained during 28 days of storage at 20°C. Only the chemical sludges
provided a specific resistance; however, that was low enough (less than
~\QU m/kg) to provide effective dewatering of the stored sludge on a
vacuum filter or filter press when the lime addition was the minimum
required to stabilize the sludge during storage.
The sludge drainage rate (m£ of filtrate/hr) on a sand filter
decreased as a function of storage time when mixed primary-chemical or
secondary-chemical sludges were drained, even though these sludges had a
specific resistance that was in the range where vacuum filtration would
have been successful.
With all of the lime stabilized sludges, the dosage of polymer
had to be increased as storage time increased, regardless of lime dosage,
in order to obtain a CST value of 10 to 20 seconds recommended for sludge
treatment. This is due either to production of organic acids where the
pH decreased below 11 or due to possible hydrolysis of organic matter
when the pH remained above 11 as recommended. With the primary sludge,
the polymer dosage required increased as the lime dosage increased.
It was concluded that:
1. Lime-treatment of raw and mixed sewage sludges to a pH above
12 after storage for 28 days will improve and maintain sludge
filterability.
2. Lime additions for stabilization will not give proper conditioning
for dewatering by filtration.
3. Sludge drainage of lime-stabilized sludge will increase with
increase in lime but decrease again during storage.
4. The decrease in drainage rate did not affect the total volume
of water that could be drained from the sludge.
5. The conditioning of lime-stabilized sludge with high MM polymers
will require an increased polymer dosage with increased storage
time.
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6. Primary sludges required higher polymer dosages with higher
lime additions; the opposite was true with mixed primary-
chemical and mixed secondary-chemical sludges,
B. Prepared Discussion
R. I. Dick (USA) pointed out that lime stabilization both
reduces odor and bacteria; however, the effect is only temporary. The
authors indicate that the lime dosage for stabilization is inadequate
for sludge conditioning. Do the authors therefore recommend use of
additional lime for conditioning or the use of lime plus a conditioning
chemical?
Dick suggested that basic concepts need to be identified in
evaluating the test results:
1. The authors called for a pH of 12 for stabilization. How
confident are they in selecting this value?
2. In the primary sludge conditioning with lime and polymer,
continued stirring seemed to improve dewaterability of the
sludge. Does this indicate inadequate contact between sludge
and polymer earlier?
3. The paper included no data on the compressibility of the sludge.
Did the authors collect any?
4. What is the most cost effective way of handling sludges of the
type tested? Using auxiliary chemicals or not?
C. Floor Discussions
David Barnes (Australia). Did the authors look at the quality
of the water drained from the sludges? His experience was that you get a
highly polluting return flow using the treatment approach discussed in the
paper.
Ron Hicks (NZ). Can animal wastes be limed using the treatment
described and sprayed onto land?
Reply - No studies were conducted by the authors of the cost
effectiveness of lime-stabilized sludge. Webb in England found that
when using lime for stabilization, you also need to use copperas or
polymer in combination with lime. When using centrifuges, polymers are
also needed.
The basic parameter has to be the effect of pH and it is and
was the only parameter of concern. In fact, it was the only one recorded.
CST times decreased with longer stirring time because mixing with the
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higher dosages is less effective and longer mixing times are required.
Yes, it is a mixing problem. Unfortunately, sludge compressibility was
not measured.
Hydrolysis of organic matter will take place at a high pH and
produce a highly putrescible filtrate water. It was not considered in
the paper, but is a problem in Norway.
The authors have no experience with lime-treating animal wastes
but you should have no obnoxious odors with lime at pH 12, except for
ammonia which would be released at that pH.
IV. CRITIQUE OF SESSION
This paper received generally a so-so reception, principally
because the use of lime-stabilization and storage of sludge is not an
accepted practice in the U.S., Australia and most developed nations. The
test results seemed to merely confirm experience of most of those who
had ever used the process.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
This paper would appear to have no significance to U.S. practice
or need for research activity.
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I. SESSION
A. Theme of Session: Pyrolysis of Sewage Sludge and Refuse
B. Papers Presented: 29.
32.
35.
Studies on Pyrolysis Process of Sewage
Sludge.
T. Majima, K. Tadao, M. Naruse, M. Hiraoka
(Japan)
Combined Disposal of Sewage Sludge and
Solid Wastes by the Pyrolytic Process.
N. Brovko, R. A. Lockwood, R. R. Bowerman,
K. Y. Chen (USA)
Disposal of Sludge Using Solid Wastes as
Fuel with Resource Recovery and Creation
of Gas End Product for Utility Use.
I. L. Bogert, D. S. Greene (USA)
II. REVIEWER
A. Name: John Zoltek, Jr.
B. Position and Affiliation:
Associate Professor
Department of Environmental Engineering
Sciences, University of Florida
Gainesville, Florida 32611
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 29
The first paper dealt with the pyrolysis of raw sewage sludge
that was vacuum filtered with calcium hydroxide and ferric chloride as
chemical aids. A 25 kg of dry sludge/hour pilot plant was used to deter-
mine the feasibility of two pyrolysis processes, noncombustion and partial
combustion. The paper presented much detailed data, and should be very
useful for those interested in this subject. Solids reduction was approx-
imately the same as what would be achieved with incineration, about 50
percent. For comparison with the pyrolysis runs an incineration experi-
ment was carried out at 800°C in an electric furnace. It was found that
34 percent of the total Cr was oxidized to Cr6+ in the incineration process.
In the noncombustion and partial combustion processes the amount of total
Cr oxidized was negligible. Apparently, this was a very important con-
sideration in Japan, and rightfully should be considered in the United
States. The pyrolysis process produced an objectionable odor, but this
odor was decomposed by secondary combustion. Pyrolysis utilized two-thirds
as much fuel when compared to incineration, due to the heat value of the
gas produced by pyrolysis. The quantity of water used for scrubbing was
rather large, but analyses indicated that it was relatively free of pollutants.
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A.2 Paper No. 32
The second paper dealt with the pyrolysis of sewage sludge com-
bined with refuse. The experiments were performed on a small laboratory
type pyrolysis unit and it is questionable whether the data can be directly
scaled up for prototype use. Theoretical calculations were made to deter-
mine what gaseous end products would be formed at different pyrolysis
temperatures and these theoretical values were found to be substantially
different from what was observed in the experimental unit. This discrep-
ancy probably was a result of the small size of the unit as well as poor
heat transfer at the surface of some of the solid particles. It was
estimated that primary sludge must be dewatered to at least 22 percent
solids for the pyrolysis of the combined sludge and refuse to be economi-
cally feasible. The moisture content in both the sludge and refuse was
the most important economic parameter for heat recovery and efficiency.
A.3 Paper No. 35
The third paper dealt with an engineering-calculation type of
study on the disposal of sludge using solid waste as fuel. The primary
objective was creating a gaseous end product that could be sold to a
utility for its heat value. No experiments were performed, other than
analyses on raw sludge and refuse. The process used pure oxygen (20
percent of feed by weight) and the ash was in a slag form that was readily
disposable by use for road construction, landfilling, etc. This slagging
type of pyrolysis unit produced the lowest amount of ash of any of the
pyrolysis processes discussed, compared as a percentage of feed weight.
The process was calculated to be economical in the New Jersey area, probably
because of the high cost of natural gas, a condition that may not be met
elsewhere. The authors stated that there was no air pollution because
the gas was being sold, but special precautions may have to be taken at
the site where the sold gas would be burned for power production. No tests
were run to determine what kind of air pollution was produced by burning
the off gasses. No cost estimate was made for treating the scrubbing water
but a rough calculation indicated that it would be on the order of $2.00/ton
of refuse, compared to a total net cost of $62/ton of refuse for the pyrolysis
system. It was calculated that the slagging type of pyrolysis unit would
cost approximately 77 percent of refuse incineration.
B. Prepared Discussions
B.I One of the main points brought out during the prepared discussions
was that very little full scale operating data are presently available for
the pyrolysis of sewage sludge, refuse, or a combination of the two. Los
Angeles-Orange County Joint Authority have a waste pyrolysis unit presently
in operation, and Baltimore and San Diego have units under construction.
It was asked if the authors of the first paper had any idea what the optimum
air ratio was for no Cr° production and the author indicated that recent
tests showed it to be about 40 percent. It was also noted that the rather
large amounts of water used during the experiments reported on in the first
paper may be responsible for the low levels of toxic concentrations that
were found. It was felt that in normal operation the scrubbing water quantities
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would be far less than were used for the first paper's experiments, giving
proportionally higher effluent concentrations.
B.2 The discusser for the second paper pointed out that a pyrolysis
project in Seattle that was to produce ammonia via pyrolysis energy was
turned down and a waste pyrolysis project in Minneapolis was abandoned by
the city fathers after a negative report from consultants. It was also
stated that a pyrolysis plant in Baltimore will need $6 to$10million more
to correct air pollution problems due to smaller than expected particles
in the gaseous stream. It was felt that quenching water and cooling water
blowdown can be serious pollution problems and should be carefully inves-
tigated when any pyrolysis tests are performed. The discusser also felt
that the second paper predicted fuel values needed for pyrolysis that
probably were on the low side, and during later discussion the author
indicated this might be true. It was generally agreed that larger scale
experiments were necessary, particularly to determine what effects sewage
sludge components such as grit and grease might produce.
B.3 There was very little negative comment during the discussion of
the third paper but the discusser felt that hydrogen cyanide production
might be a problem if it were carried over to the scrubbing water.
C. Floor Discussions
During the floor discussions it was pointed out that the pyrolysis
temperature would have a significant effect on whether low molecular weight
products were formed, such as gases, or whether there would be a significant
amount of high molecular weight products such as oils and tars. It was
generally agreed by various floor discussers that pyrolysis probably could
treat refuse, or refuse combined with sewage sludge, for less than the cost
of incineration. From the papers and from other comments it appears that
the total cost of pyrolysis is probably somewhere between 70-80 percent of
the cost of incineration. However, it was pointed out that until large
scale plants are put into operation, it is impossible to predict total cost
from small scale pilot plant work. Low temperature pyrolysis has the advan-
tage of not oxidizing chromium to Cr°+ which might leach out of the ash
when the ash is used for landfilling. It was generally felt that the water
content of both the refuse and the sludge would be important in determining
the economics of any pyrolysis unit. Sewage sludge should probably be
dewatered to at least 20 percent by mechanical means, with the use of poly-
mers if necessary, in order to minimize the heat loss in heating up the
excess water. The grease in sludge may create air pollution problems that
are not present in pyrolyzing refuse because they produce an odor, are
visible and are not readily water soluble, making their removal difficult.
One floor discusser felt that the final paper was probably the most impor-
tant at the conference, but this reviewer feels that it may be lacking in
value due to the fact that no actual experiments on the pyrolysis technique
were performed. The calculations were based on data that were given to
the authors by manufacturers of the pyrolysis unit. A demonstration project
is presently underway in South Charleston, West Virginia. The authors con-
ceded that their calculations would have to be finalized after results were
in from the South Charleston demonstration project. One floor discusser
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felt that it might be possible to create a meld of pure metals if the
temperatures were raised in the pure oxygen slagging type of pyrolysis
units. This could be an important consideration in simplifying the
recovery of metals. There was some concern by various floor discussers
as to how much heavy metals remain in the sludge during the slagging
process. This type of information was not available because of the
absence of experiments.
D. Other Observations and Comments
In general all of the papers for this session were well
received. It is a relatively new field of interest and any contributions
were felt to be a welcome addition to a rather scarce body of knowledge.
The Japanese seem to be very interested in pyrolysis and it is suggested
that anyone interested in the field should acquaint himself with Japanese
literature. It may be advisable for some of the U.S. project investigators
who are working on pyrolysis units to arrange a trip to Japan to observe
their experiments and techniques first harid. Many of the details for
such a trip can be worked out beforeharid by mail and it is felt that it
probably would be a worthwhile investment of research funds. It should
be pointed out that there was a serious language problem between English-
speaking and Japanese-speaking scientists at the.conference and any such
scientific trip should arrange a translator to assure proper understanding.
Although the Japanese made a valiant effort to communicate in English at
the conference, overall mutual understanding (from the experiences of this
reviewer) ranged from nonexistent to poor.
IV. CRITIQUE OF SESSION
The research reports were well received and it was surprising
that the last paper was as well received as it was. There seems to be a
serious lack of information on pyrolysis of refuse and sludge so a calcu-
lation type of paper with the assumptions that are inherent in such a
work usually is viewed skeptically. The first two papers covered a fair
range of experiments, from noncombustion and partial combustion pyrolysis
of sewage sludge to noncombustion combined sewage and refuse.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Sludge and solid waste disposal is presently one of the major
problems confronting the United States. It was rather disappointing to
see that the papers dealt primarily with pyrolysis producing excess energy
so that the process could be self-sustaining rather than producing a solid
or liquid end product that might have a high commercial value. It was
generally felt that the solid ash was only useful for fill or aggregate.
However, it was significant that the scientists at the conference felt that
pyrolysis can probably be accomplished utilizing less net energy than
incineration. Pyrolysis does seem to provide a good answer for both sludge
and refuse disposal for the large cities that are not near agricultural
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areas. It is felt by this reviewer and others at the conference that the
entire picture of sludge disposal should be approached from the point of
view that the sludge contains valuable elements (nitrogen and phosphorus)
that may be of use to farmers. Refuse, rather than just being considered
for its heat value, should be considered as a source of raw materials such
as metals, glass, plastics, etc. Pyrolysis seems to solve a number of
sludge disposal problems but it should be realized that the gas scrubbing
operations at the end of a pyrolysis unit probably will produce some water
pollution that will have to be treated. It is felt that research in the
area of pyrolysis should continue, perhaps at a slightly faster pace than
is presently underway. It was generally agreed by most of the scientists
that this reviewer personally conferred with that one of the major stumbling
blocks for many engineers trying to solve waste pollution problems is their
failure to realize that "everything has to be somewhere." Essentially,
most of the techniques we presently employ for waste treatment force the
pollutant to either go through a chemical or phase change or to go to a more
concentrated state, where the ultimate disposal might be easier to handle.
Looking ahead to the future it is difficult to imagine that we will not
eventually be a total reuse society. Perhaps we are at the point now that
we should begin thinking along these lines.
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SESSION
A. Theme of Session: Sludge Thickening
B. Papers Presented: 24. Dissolved-Afr Flotation in Activated
Sludge.
J. Bratby, G.v.R. Marais (South Africa)
II. REVIEWER
A. Name: Bart T. Lynam
B. Position and Affiliation:
General Superintendent
Metropolitan Sanitary District of
Greater Chicago
Chicago, Illinois
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 24
The authors in their paper "Dissolved-Air Flotation in Activated
Sludge" summarize much of their experimental work and present a design
example. They propose that the dissolved-air flotation process is useful
for both sludge thickening as well as viable alternative for secondary
sedimentation. While the jse of dissolved-air flotation for sludge thick-
ening has been well documented, it seems doubtful that it would be a
practical alternative to secondary clarification by gravity settling.
This is in light of the fact that no data were presented to justify sec-
ondary clarification by dissolved-air flotation.
Many theoretical and empirical relationships which would affect
the design of a dissolved-air flotation system were presented in the paper.
These relationships were based on experimental work conducted by the
authors and reported in earlier publications. However, it is difficult
to evaluate these relationships presented since the scale of the equipment
used to generate the data is not described and the earlier publications
cited are of limited circulation. The importance of the size of the units
used was pointed out by Ettelt1 who, in his dissolved-air flotation studies
at the Metropolitan Sanitary District of Greater Chicago in the early 1960's,
found that the adhesion efficiency (percent of total air supplied attached
to solid surfaces) in the laboratory scale equipment was substantially less
than in the full scale units. Ettelt attributed the reduction to a lower
intimacy of contact between bubbles and solids in the full scale equipment
and the higher turbulence caused by the inlet velocities in the full scale
units, which tended to shear the gas bubbles from the solid particles.
Thus Ettelt found that the inlet design, i.e., reduction in turbulence
and increasing the contact time, was the key to the successful operation
of the full scale dissolved-air flotation units. Consequently, since the
authors emphasized the empirical and theoretical aspects of dissolved-air
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flotation as opposed to the practical aspects of full scale operation,
one must assume that much of their experimental work was done on laboratory-
scale equipment.
The authors have chosen not to reference and review the work of
others who have published in this area. While the use of dissolved-air
flotation is not extensively being used, it is not a new process and there
are many who have worked on the process and have made important contribu-
tions to this technology, for example, Ettelt.
B. Prepared Discussions
The discusser, Mr. A. Baud (France) brought out some interesting
points concerning the paper and the dissolved-air flotation (DAF) process
in general. He felt that even though the DAF process was more sophisticated
than gravity sedimentation, the DAF process has its advantages in providing
a more concentrated thickened sludge (2 to 3 percent for gravity thickening
compared to 3 to 5 percent for DAF) at much higher solids loadings.
The main point of disagreement with the authors was in the
thickening ability of the DAF process. Mr.'Baud had observed DAF units
capable of producing a thickened sludge of 4 percent at sol'ids loadings
of 100 kg/m2/day, while the pilot plant results of the authors would have
predicted a 4 percent sludge at a solids loading of only 40 kg/m2/day.
Bratby countered that the observations made by Baud could have been with
DAF units which were using polyelectrolytes. In such a case, the poly-
electrolytes could have aided the thickening ability of the DAF unit.
However, what should have been pointed out was the fact that differences
in the sludge characteristics could have accounted for discrepancies in
the observations. In fact, Bratby points out in response to a question by
Baud concerning whether or not the mathematical model in the paper was
universal or not, that the model is limited to the sludge tested and that
the influence of sludge characteristics (SVI, size of floe, etc.) on the
thickening ability of the DAF was not studied and was one of the limita-
tions of the experimental results.
C. Floor Discussions
There were several questions from the floor which stimulated
some interesting discussion concerning the paper by Bratby and Marais.
The use of the dissolved air flotation process in place of secondary sedi-
mentation which was suggested by the authors received a considerable
amount of discussion. One question concerned the cost comparisons of the
DAF and the secondary clarifier and the effluent quality one could obtain
from a DAF. Bratby pointed out that the DAF total capital costs were more
costly at mixed liquor concentrations of 1000 mg/£ and higher. However,
the cost comparisons would be even more pessimistic if the operating cost
were included which would no doubt be much higher in the DAF unit. This
fact coupled with the fact that most activated sludge plants operate in
the 2000 to 3000 mg/£ range makes the use of the DAF even more questionable.
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In spite of the above economic shortcomings of the DAF, Bratby felt that
the DAF should be considered since there would be less land required and
the sludge would be thicker and thus possibly require much less further
dewatering processes. Also, he pointed out that in his studies the effluent
quality from the pilot DAF unit which he used produced effluent suspended
solids in the range of 5 to 10 mg/l, which is comparable to a secondary
clarifier. Nevertheless, this kind of effluent quality needs to be proven
on a large scale DAF unit.
Another discusser concurred with Mr. Baud and felt that the
results obtained were much poorer than he had observed. In his observa-
tions of DAF units in Sweden, he found that at loadings of 100-150 kg/ra2/day,
a 4-6 percent sludge was obtained. With the use of polyelectrolytes
(1 kg/ton), 8 percent sludge was obtained at loadings of 200 kg/m2/day.
Mr. Bratby commented that the use of intermittent scrapers could have
accounted for the differences in his observations and the results Bratby
observed. In Bratby's closing statement, he emphasized the fact that the
effects of different sludge characteristics on the performance of the DAF
were not studied and this was one of the major limitations of the experi-
mental work.
IV. CRITIQUE OF SESSION
The paper on "Dissolved-Air Flotation in Activated Sludge" stimu-
lated some limited discussion and interest. From a practical point of
view, much of the presented information had been previously reported over
the past 15 years in a progressive manner in various technical publications
throughout the world. I cannot judge the report to be highly significant.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
In my opinion much of the paper is existing technology previously
reported and does not require new research. Full scale work on dissolved-
air flotation is progressing in the United States. The United States
Environmental Protection Agency's program of funding under Public Law 92-500
will bring new designs as wastewater treatment plants begin to create acti-
vated sludge in order to upgrade present treatment.
REFERENCES
Ettelt, G. A., "Activated Sludge Thickening by Dissolved Air Flotation,"
PA.OC. 79-tft Annuo£ Purdue InduA. WaAte. Con$., Lafayette, Indiana, Hay 1964.
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I. SESSION
A. Theme of Session: Process Variability in Activated Sludge as
Related to Temperature
B. Papers Presented: 27. Variability of Temperature and Other
Process Parameters - A Time Series
Analysis Sludge Plant Data.
K-C. Lin, G. W. Heinke (Canada)
II. REVIEWER
A. Name: Bart T. Lynam
B. Position and Affiliation: General Superintendent
Metropolitan Sanitary District of
Greater Chicago
Chicago, Illinois
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 27
The objective of this paper was to study the variability of
activated sludge plant data pertaining to the parameters such as temper
ature, BOD5, suspended solids, mixed liquor suspended solids and sludge
volume index. This has been attempted by employing harmonic analysis
and spectral analysis, the tools available in time series analysis1.
The basic assumption in application of harmonic analysis is
that the time series is made up of sine and cosine waves with different
frequencies. More formally we assume that if zt denotes an observation
from time series
zt =
cos (2*^1) + 01 sin (2irf.t)] + et (1)
where f-j = i/N is the ith harmonic of the fundamental frequency 1/N.
et is assumed to be independent and normal with zero mean and variance a2.
This model is tested against
zt = a0 + et (2)
as truly random model. A test for the fit shows if the series contains
a systematic sine component having frequency fj, amplitude A and phase
angle F. An estimate of sample spectrum can be obtained from (1).
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However, if the stationary time series are characterized by random
changes of frequency, amplitude and phase, the sample spectrum fluctu-
ates wildly and is not capable of meaningful interpretation.
The statistical tools employed in this paper are powerful;
however, the impact of the conclusions drawn in this paper cannot be
validly ascertained.
In our experience, we find that it is desirable to check the
assumptions made on the stochastic term in the model as to its probability
distribution. The common assumption of normality does not seem to hold
for many parameters that are of interest in wastewater research. It is
our opinion that the authors have made an excellent effort to obtain the
inferences reported in the paper. However, the authors have made little
effort in translating the meaning of their conclusions to readers who are
not familiar with the terminology of spectral analysis.
At MSDGC, we are interested in employing autoregressive tech-
niques as described in 2. The basic idea is as follows: Fourier series
models approximate continuous functions on (0.2ir). However, any con-
tinuous function can be approximated by polynomials (using Stone-Weirstrass
Theorem). If we now add a stochastic component to these approximations,
we incorporate randomness into the process. Autoregressive model is a
discrete analogue of polynomial function. Thus, it seems that more infor-
mation can be obtained as to the behavior of any one parameter. Further
transfer function models can be fitted to study the relationships that
might exist between two parameters.
In the final analysis, the results of the above paper can be
only considered as preliminary results, and more work needs to be done
before the inferences could be of tangible utility in the study of acti-
vated sludge processes.
B & C. Prepared and Floor Discussions
The comments contained in both the floor and formal discussions
did not contain any significantly new information regarding statistical
treatment of plant data. All present seemed to agree that the statistical
treatment used was interesting and could be of value to the sanitary
engineering profession.
IV. CRITIQUE OF SESSION
The paper was not received very well due to the special nature
of the report. The paper does contain original work on the relationship
of the various process parameters. The statistical analysis of the data
and the techniques used were impressive and of high quality. The author
presented an analysis of a large volume of data which can be readily
understood.
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V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The obvious use of temperature in the control of activated
sludge processes makes the paper a source for reference to techniques for
analysis of data as presented. Additional research is needed in the
practical use of data such as temperature in the control of activated
sludge plants. However, other parameters may be more readily available
as primary control or direct process control.
REFERENCES
Jenkins, G. W. and Watts, D. G., Spectral Analysis and Its Applications,
Holden-Day, San Francisco, 1968.
2Box, G. E. P. and Jenkins, G. W., Time Seriejs Analysis Forecast and
Control, Holden-Day, San Francisco, Revised edition, 1976.
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I. SESSION
A. Theme of Session: Aeration Ponds
B. Papers Presented: 30. Comprehensive Temperature Model for
Aerated Biological Systems.
Y. Argaman, C. E. Adams, Jr. (USA)
33. The Efficacy of an Equalization Pond in a
Water Reclamation System.
B. M. Van Vliet, H. H. S. Wiechers,
0. 0. Hart (South Africa)
36. Scale-up Methodology for Surface Aerated
Reactors.
N. W. Schmidtke (Canada), I. Horvath (Hungary)
II. REVIEWER
A. Name: Edward S. K. Chian
B. Position and Affiliation:
Associate Professor of Environmental
Engineering, Department of Civil Engr.
University of Illinois at Urbana-Champaign,
Urbana, Illinois 61801
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 30
The temperature dependence of biological oxidation is very important
in considering both the efficiency of aerated lagoon treatment of wastewater
and the costs associated with it. Therefore, accurate prediction of temper-
ature of aeration ponds under cold and warm weather conditions is required to
determine the substrate removal rates and thus to determine the detention times
under cold weather conditions and the subsequent oxygen requirements under warm
weather conditions. Considerations were given in Paper No. 30 to all the energy
terms associated with the heat balance around a completely-mixed aeration basin,
along with a comprehensive review of methods available for predicting heat
evolution and dissipation under different process conditions. Confirmation
of the temperature model has been carried out on a 12-month basis while oper-
ating a full scale aeration basin treatment system. The good agreement between
the actually measured and the calculated temperatures indicates the validity
of the temperature model as proposed by these authors.
A.2 Paper No. 33
The performance of an equalization pond which was incorporated later
in a water reclamation system between the high lime process and the ammonia
stripping tower was discussed in this paper. The need for such an aerated
pond arises from the poor performance of a current water reclamation system
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without an equalization basin. In addition to affecting quality equalization,
this pond was also found to improve the efficiency of an ammonia stripping
tower, to reduce calcium carbonate supersaturation, to provide a microbiologi-
cal barrier, and to facilitate the downstream control of breakpoint chlorination.
A.3 Paper No. 36
The complexity of industrial waste treatment process design using
aeration basins dictates that prototype plant simulation using models in the
laboratory be used to minimize risk of process failure. The scale-up of sur-
face aerators was discussed in this paper using three geometrically similar,
square aeration tanks to provide data for the development of a scale-up equa-
tion based on the postulate that equal mass transfer rates in model and
prototype will give equal process results. The postulation of using equal
mass transfer coefficients, such as k|_a, for scale-up appears to be a better
one that that of using equal power input per unit volume, with geometrically
similar systems. Therefore, the use of a parameter relating to performance
of the system, such as kj_a in the case of oxygen transfer, gives a valid approach
in scale-up. The apparent weakness of this approach is that the biological
similarity between the prototype and the model systems has not been considered
in scale-up. This can be circumvented, however, by incorporating the correction
term a for k|_a based on the average value of a obtained from a number of
biologically similar systems.
B. Formal Discussions
B.I The discusser commented that temperature is only one of the impor-
tant parameters involved in a biological treatment system. Others such as
the nature of the waste materials, pH, ionic strength and dissolved oxygen
should all be considered. Only when all of these variables are well defined
can a temperature model be developed meaningfully. A number of questions
were also raised by the discusser as to the heat gained from a compressor
using either air-cooled or water-cooled systems, heat loss in the distribu-
tion system employing an air-cooled system, the rate constant of the auto-
catalytic reaction of the biological system, as well as the correctness of
using similar expressions in calculating the cooling effect of mechanical
and diffused aeration systems.
B.2 The discusser commented that the concept of incorporating flow
equalization in a wastewater treatment system is by no means a new one.
Apparently these authors faced a practical problem as described in their
presentation. They did it simply for the purpose of solving problems encoun-
tered in their wastewater reclamation system. The additional advantages
of improved ammonia stripping, reduced calcium carbonate precipitation
requirements, and improved microbiological quality may be unexpected bene-
fits of such equalization ponds. This may be why these authors were so
excited about the findings of all such additional benefits. The way these
authors reduced data of operation in an empirical mathematical model impressed
the discusser as being an elegant one. However, the question of the mecha-
nism of removing microorganisms with the equalization pond was raised. Also,
the rationale behind the selection of 125 hour residence time was brought out
by the discusser.
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B.3 The major concern as raised by the discusser was whether the
correlation developed for scale-up of an aerator is applicable to geo-
metrically dissimilar systems as well as to prediction of power require-
ments. The discusser's comment that the paper presents a scale-down
instead of a scale-up of the surface aerator appears to be a valid one
since most of the practical design involved in predicting power require-
ments for fermenters of various sizes is based on data available within
the size range rather than extrapolating beyond experimental data while
using a geometrically similar system.
C. Floor Discussion
The correctness of using the term free energy in energy balance
is doubtful. Entropy is a more correct term and should be used. The
question on the sensitivity of the heat input terms, such as solar,
mechanical and biological, etc. was raised. The opinion of the authors
is that the sensitivity is overridden by other parameters such as tempera-
ture.
High heat loss through evaporation while using the surface
aerator can be overcome by using a diffused air system. Surface aerators
should be employed when dealing with a high strength waste. This is
especially true under warmer weather conditions. Diffused air systems
should be used when treating a dilute waste especially under colder
weather conditions. This is due to its lower rate of evaporation.
Since the biological treatment rate constant is also a function
of the BOD remaining in the well-mixed reactor according to the Monod's
model, it should be considered along with the temperature effect on the
rate constant.
The basis for the selection of detention time was an arbitrary
one which was somehow related to the diurnal variations in wastewater.
The mechanism of pathogen removal was probably due to exposure to high pH
for an extended period of contact. However, simple physical adsorption
on suspended solids should be explored.
The question of whether the scale-up equation developed on the
basis of using a single aerator is applicable to a multiple aerator system
was raised. The performance of an aerator in the presence of other
aerators surrounding it is indeed affected, since the criterion of geo-
metrical similarity between these systems will no longer hold. A 15
percent reduction in oxygen transfer with the use of a multiple aerator
system has been experienced.
Other questions regarding scale-up of power input to the aerator
were raised. The relationship between kj_a and P/V varies from 0.95 to 0.65
power depending on the size of the system. The smaller power is applicable
to a larger system.
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IV. CRITIQUE OF SESSION
In view of the amount of literature work involved and the good
agreement between the measured and the calculated temperature data
observed in a 12-month period with an existing aeration basin, the quality
of this paper is excellent. The paper was well received although the
apparent lack of originality is shown by the previous work reported by
other investigators.
The quality of the equalization pond paper was good in that
the plant operation data have been formulated into a mathematical model
which can be transferred to study other cases. The originality of incor-
porating an equalization pond in a wastewater treatment system is, however,
not there. The mechanism of pathogen removal as proposed by the authors
should be substantiated in the laboratory using the same microbial flora
as indicator microorganisms.
Although the quality of the scale- up research was good, it was
not too well received from the floor. There were controversies on the
question of geometric similarity^ relationship of P/V to ^a of different
sizes of aeration basins as well as the use of multiple aerators and
other matters. While the overall originality of the paper was not evident,
the paper does provide certain originality in relating ki_a/N (where N is
revolutions of the impeller per unit time) to Fronde number as well as
to N and Di (impeller diameter).
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Since most parts of the United States are located at latitudes
that have four distinct seasons, adequate temperature projections would
alleviate failure of biological treatment systems to achieve design dis-
charge goals or gross overdesign. Tin's paper is therefore pertinent to
the U.S. needs in solving design problems associated with aeration basins.
In view of the trend in reclaiming wastewater in arid regions of
the United States, the advantages of incorporating a surface aerated
equalization pond should be of value to us.
While extensive work has been done in defining power character-
istics of mixing impellers in a fermenter type aerating system, a paucity
of information is available in the literature concerning oxygen transfer
and agitator geometry relations as applied to surface aeration systems
commonly employed in wastewater treatment. The paper dealing with scale-up
of aerators is pertinent to U.S. needs in solving problems regarding
design of surface aerators.
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I. SESSION
A. Theme of Session; Advanced Waste Treatment and Physicochemical
Treatment of Wastewaters
B. Papers Presented: 37.
Investigations into the Lime Precipitation
of Raw Municipal Wastewater.
D. Jenkins, F. M. Lee (USA)
40. Calcium Carbonate and Magnesium Hydroxide
Solubility Product Values for Heterogenous
Systems.
H. N. S. Wiechers (South Africa)
43. Advanced Wastewater Treatment by Chemical
Precipitation with Lime and Ammonia
Stripping in Ponds.
E. Idelovitch, T. Roth, M. Michail
(Israel)
46. Improvement of Tertiary Filtration Effi-
ciency by Upgrading Biological Activity.
G. M. Faup, J. L. Bebin, J. C. Jacquart
(France)
II. REVIEWER
Name: Walter J. Weber, Jr.
Position and Affiliation: Professor of Environmental and Water
Resources Engineering and Chairman of the
Water Resources Program
The University of Michigan
Ann Arbor, Michigan
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 37
The paper was concerned with laboratory jar tests and a pilot
plant study, in a two gallon per minute continuous flow system, using
sewages of different strength and with normal diurnal flow variations.
The object of the study was to assess the capabilities of this process
and to provide data which might help to reduce costs and improve the
efficiency of primary treatment.
Nine suspensions were prepared by adding powdered quicklime to
a container in which vigorous mixing kept the lime in suspension. The
lime was added at 360 mg Ca(OH)2/£, sufficient to maintain a pH of 11 in
the clarified effluent. The pilot plant had four compartments, in each
of which the nominal residence time was six minutes. The paddle speeds
-------
produced velocity gradients (referred to as "G") measured in seconds .
These gradients varied from 15 to 100 sec~l. One particularly interesting
aspect of this study concerned the nature of organic compounds which are
removed by lime treatment. The organics measured in solution were those
that remained after filtration. These organics and those in suspension
were examined by gel-chromatography in order to determine molecular weight
distribution.
The essential findings of the study may be summarized as follows:
1) optimum removal of suspended solids and COD by lime treatment of sewage
is obtained at "G" values of 30 sec"1 but it is not critical if this value
is exceeded; 2) the critical conditions involved in the removal of suspended
solids, COD and phosphate from sewage by lime treatment could be achieved
in 12 min at "G" values of 50 sec'1; 3) high concentrations of lime when
added to sewage take longer to dissolve than lower concentrations; 4) cal-
cium carbonate formation on dissolving lime particles is thought to be more
effective in preventing lime dissolution than magnesium hydroxide forma-
tion; 5) lime dissolved in recycled effluent gave better results than lime
first dissolved in water; 6) the distribution of molecular weights of the
organic components in sewage remained unchanged after liming; 7) the dis-
tribution of low molecular weight organic components was the same after
lime treatment as before; and, finally, 8)'lime treatment is not effective
in removing low molecular weight substances.
A.2 Paper No. 40
Dr. Wiechers reported studies at Pretoria, South Africa, which
he indicated were designed to determine "solubility products" for calcium
carbonate and magnesium hydroxide in "stable" lime-treated and recarbo-
nated secondary effluents. The "solubility products" were correlated with
the characteristics of the wastewater effluents by empirical models.
Further, degrees of supersaturation for CaC03 and Mg(OH)g were
determined for the effluents from various unit processes of a wastewater
reclamation plant. Wiechers reported that when predictions for these
numbers (degrees of saturation) were based on the solubility products
determined in his studies, they agreed more with actual findings than when
such predictions were based on conventional thermodynamic solubility
products.
The author indicated that the solubility products determined
experimentally agreed closely with literature values for lime-treated raw
sewage and other heterogeneous wastes and claimed therefore that their
application is not limited to secondary effluents. He further stated that
these solubility products enabled more realistic, yet general, calculations
of CaC03 and Mg(OH)2 precipitation in lime treatment of wastewater, and
determination of the stability of effluents produced by lime treatment,
than do conventional thermodynamic solubility products.
A.3 Paper No. 43
This paper dealt with the wastewater treatment scheme of the
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first stage of the Dan region reclamation project in Israel. The project
provides for advanced treatment of wastewater from the Tel Aviv metro-
politan area and indirect reuse of effluent by ground water recharge.
The advanced treatment consists of chemical precipitation by high lime,
with magnesium flocculation, filtration, and detention of the lime treated
effluent in polishing ponds, mainly for the purposes of free ammonia strip-
ping. Stabilization by C02 is carried out before ground water recharge.
The lime sludge is conveyed to sludge drying beds before final disposal.
The basic operational parameters which are considered in the paper follow.
The pH in the secondary effluent ranged between 8 and 8.8, and was raised
by high lime treatment to values of about 11.5. Because of variations
in the sludge blanket clarifier operations, they were varied between roughly
11 and 12, but averaged 11.5. The studies indicated that the optimum pH
should be between 11.2 and 11.5. Magnesium concentrations varied between
20 and 40 mg/£. This was not enough for optimum flocculation and had to
be supplemented by addition of magnesium chloride to a level of about 45
mg/£ in magnesium. The lime dosage required, because of the high alka-
linity of the water, was about 700 mg/£. An interesting observation was
made on the effect of the polishing pond on continuing precipitation of
the phosphorus. By high lime, phosphorus was reduced to about 0.5 to 2
mg/£ whereas after the polishing pond the concentration was always below
0.4, the average being 0.3 mg/£. Ammonia stripping is the main process
of the polishing pond with a detention time of 9 days. Some ammonia is
also removed during lime treatment, but the main part of the ammonia is
removed by stripping during detention of the effluent in the polishing
pond. The pH is also reduced in the polishing pond from roughly 11.5 to
values which averaged 10 to 10.5, sometimes lower. Nitrification must be
avoided in the process since no provision is made for nitrate removal.
In summary of plant performance, virtually complete destruction of coliforms
was achieved along with about 96 percent phosphate removal, 90 percent sus-
pended solids removal, 82 percent ammonia removal, 80 percent BOD reduction,
74 percent Kjeldahl nitrogen reduction, and 72 percent removal of COD. The
authors claim that the effluent is suitable for direct agricultural, indus-
trial, and non-potable municipal reuse as well as for ground water recharge.
A.4 Paper No. 46
This paper described the results of studies of the effect of
biological growths and preaeration on the performance of sand filters used
for tertiary wastewater treatment. It further described the results of
an evaluation of an alternate filtration media for such applications,
specifically, extruded expanded clay.
With respect to preaeration ahead of sand filters, the authors
concluded that this practice 1) slightly improves suspended solids removal
(64 percent versus 57 percent); 2) marginally increases removal of dis-
solved material (expressed as COD, 11 percent versus 8 percent); and 3)
does not result in any measurable increase in retention of suspended solids
in the filter.
The authors claim that expanded clay, without preaeration, gives
better suspended solids removal than sand, but no measurably greater removal
of dissolved organic matter. With preaeration, and a flow velocity of
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10 m/hr, soluble COD removal with expanded clay increases to approximately
30 percent, compared to about 10 percent removal with sand, with or without
preaeration, and to expanded clay without preaeration. Removal of suspended
solids by expanded clay with preaeration increases to approximately 85 percent.
For a given head loss, the authors report expanded clay yields
a higher suspended solids retention than sand and this is increased further
by preaeration. The authors attribute the improved operation with expanded
clay, and with preaeration, to enhanced biological growth on the filters.
They further suggest that above some critical flow velocity (or below some
minimal detention time) the effects of biological activity become negligible;
an experimental flow velocity of 20 m/hr used in the pilot studies described
by the authors clearly yields results inferior to those obtained with a
flow velocity of 10 m/hr in a filter of 1.5 m depth.
B. Prepared Discussions
B.I Van Vuuren (South Africa) emphasized that the results of this
paper (No. 37) very clearly illustrate the superior performance achieved
when lime is added to a recycling stream as compared to direct lime addi-
tion. He substantiated some of these findings by referring to experiences
in South Africa. In mixing a lime slurry of 25 g/£ with secondary efflu-
ent they have considered it necessary to provide for a reaction stage into
which sludge from the clarifier is recycled. This provides crystal seeding
and reaction times required during low temperatures. The dilution effect
on the lime slurry is thereby automatically provided for. He cited evidence
from pilot scale studies that solubilization of solid organic substances
by lime occurs and prolonged sludge retention in the clarifier should be
avoided to avoid increases in soluble COD. Further, he stated that the
clarification process is highly dependent on the concentration level of
magnesium in the raw effluent. When deficient in magnesium, ferric chloride
addition is required. Finally, he stated that he thought that the conclu-
sions drawn by the authors that hydrolysis of high molecular weight organic
materials in solution does not play an important role is a very important
statement. He asked whether the authors had observed if solid organic
substances can be hydrolyzed by high lime treatment.
B.2 Mr. Parker (Australia) noted that the problem of achieving a
stable effluent after lime precipitation and recarbonation is of importance
not only in phosphorus removal from wastewaters but also in water treatment
plants in which the lime-soda ash softening process is used. He indicated
that the lime dosage required to remove phosphorus from domestic sewage
is primarily dependent on wastewater alkalinity and not the phosphorus
concentration peA 4e, and agreed that an understanding of the equilibrium
and reaction kinetics of the lime precipitation process is essential if
the chemical stability of effluents and the calcium dosage to achieve such
stability is to be more effectively controlled. Parker noted that calcium
carbonate solubility products for lime-treated sewage have been reported
elsewhere to be a function of waste strength but that in the present paper
Wiechers has indicated general applicability to other heterogeneous
effluents. He called for some comment by the author on the validity of
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extrapolating these solubility products and correlations, particularly to
high strength domestic sewages with appreciable industrial loads where the
ion-pairing effects with anions other than bicarbonate, hydroxyl and sulfate
may be of importance.
Regarding observations of increased calcium carbonate solubility
in heterogeneous systems relative to pure systems, Parker noted that, in
addition to the author's suggestion of ion-pairing effects and inhibition
of calcium carbonate crystallization by very low concentrations of phosphates,
Wiechers also indicated that calcium complexation with dissolved organic
matter may offer an explanation for this observation. In this regard, he
indicated it would be of interest to hear if any attempt was made to corre-
late calcium carbonate solubility products with COD and, in light of the
previous paper (Jenkins and Lee), with magnesium concentration. He noted
that an objective of the author's study was to establish what constitutes
a stable water after precipitation and that in the past the Langlier stability
index and the method of Caldwell and Lawrence have been used to assist in
determination of the chemical stability of lime-treated and recarbonated
effluents from the lime-soda ash softening process. These methods require
calcium, alkalinity, pH, temperature and ionic strength data to determine
effluent stability. Wiechers, Parker commented, claims that solubility
data, with allowance for some ion-pairing effects, can be used to predict
chemical stability of effluents. Parker noted that since the practical
effectiveness of any stability criterion is indicated by improved control
of the precipitation and recarbonation processes, it would be of interest
for the author to comment on any actual plant data indicating improved
effluent stability by utilization of the solubility product values and cor-
relations determined in this study.
B.3 Wachs (Israel) commented that, although the title of the paper
describes lime treatment as chemical precipitation, when the pH is raised
by the addition of lime to pH values reaching 11 and 12, other processes
take place besides precipitation. One of these processes is the breakdown
of high molecular weight organic molecules into molecules of smaller molecu-
lar weight. He showed a slide of some work at the Technion showing percen-
tages of different fractions of organic matter, in terms of molecular weight,
corresponding to before lime treatment and after lime treatment.
He indicated that these data suggested that the biodegradability
of organic matter remaining in solution after lime treatment will be sub-
stantially increased by the treatment, and that one would therefore expect
increased biological activity on the surface of the sand into which such
waters are injected. This could cause fouling and plugging of the aquifer
due to increased biological activity although the TOC of the injected water
should be improved (reduced). Further, he noted that ground water recharge
applications must take careful consideration of the stability of the efflu-
ent with respect to calcium and phosphorus. Unless this stability is
insured, the precipitation of calcium deposits in the aquifer may cause
a gradual decrease in the aquifer capacity. He indicated that the results
presented in the paper had been obtained during a summer season and that,
because temperature affects several of the processes occurring in the
system, it would be of interest to supplement this information with data
obtained during winter operation.
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B.4 Eckenfelder (U.S.). Filtration following biological treatment
has traditionally been for the purpose of removal of suspended solids and
the BOD associated with these solids. The work of this paper and of other
reports that have appeared recently would indicate that with proper design
and operation of the filter, substantial soluble BOD and associated COD
can also be removed. Work reported recently by the Tokyo Metropolitan
Government indicates that using either upflow sand filters or mixed media
downflow filters at hydraulic loadings between 5 and 20 meters per hour, ter-
tiary filtration can achieve COD removals of 75 percent or a reduction of
the filter influent COD from 8-16 mg/l to 3-6 mg/£, and associated COD
removals of 10-20 percent. The work reported in this paper has indicated
that expanded clay media has a substantially higher specific surface and
that soluble COD removals in the order of 30 percent have been achieved
using preaeration to provide sufficient dissolved oxygen for biological
activity. It is difficult to compare the Japanese results directly with
those described in this paper because of rather different influent con-
centrations to the filter. It would appear that post-filtration with
preaeration is a feasible process where the BOD in the feed to the filter
is something on the order of 20 mg/£ or less. Studies in the United
States (Jeris &£ oJL.) using an upflow expanded bed sand filter have
achieved up to 85-90 percent BOD reduction from domestic wastewater with
retention periods on the order of 8 minutes. In these studies, sand from
the top of the filter is continuously removed and passed through a screen
to separate the biomass from the sand and the sand is then returned to
the filter. Jeris1 data do not correspond directly to the data reported
in this paper. Because of higher influent BOD, on the order of 50 mg/£,
either an aerated recycle has to be employed or pure oxygen introduced.
Eckenfelder asked the authors what their experiences had been when the
filter is used not as a filtration device alone but also as a biological
oxidation unit, relative to potential difficulties due to buildup of
biological solids in the filter, corresponding backwash frequency, and
oxygen limitation in the filter with respect to maintaining aerobic activ-
ity and high efficiency of removal.
C. Floor Discussions
C.I Paper No. 37
Kingsford (NZ). Lime treatment is becoming popular for phosphorus
stripping from effluents and it has been suggested that magnesium is nec-
essary for this purpose and that successful demonstrations have been, at
least in part, consequences of magnesium impurity in the lime. Perhaps
the principal function of the lime is to raise the pH and provide for
magnesium precipitation.
Wiechers (South Africa). Reported studies in South Africa, in
which they have also had a look at the kinetic aspects of this process,
not only at lime dissolution but also of calcium carbonate and magnesium
hydroxide precipitation, have found that the limiting reactions are the
lime dissolution reactions. Commented that the inhibition of lime dissolu-
tion by calcium carbonate and magnesium hydroxide may not be as bad as
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indicated in the paper. The kinetics'were studied by observing a change
in hydroxide concentration. In a pure system, this technique is valid.
However, when one adds lime to a heterogeneous system, such as sewage or
one containing magnesium or other alkalinity such as bicarbonates, the
hydroxide will react with the bicarbonates, the phosphates, the magnesium,
and some of the hydroxide will be removed with time. In other words, a
study of (OH-) with time is an indication of the net effect of lime disso-
lution and therefore the observations made and the kinetic model are an
indication of the net effect.
Molof (USA). Indicated two points in the paper that he thought
deserved discussion. First, in the addition of any coagulant, the result-
ing sludge is really a major consideration. Too often emphasis is placed
on the liquid clarity but not on the sludge handling characteristics.
Second, he questioned why the authors had chosen a pH of 11 to study.
Indicated that there was evidence that between pH 11 and 11.5 one starts
to get more rapid magnesium precipitation which would change the sludge
characteristics. Also questioned use of the term "high lime," indicating
that he wouldn't classify the pH of 11 as high lime.
Dunning (NZ). Indicated two questions of interest to him.
First, whether the authors had any problems in their experiments in simu-
lating diurnal flow. Secondly, relative to potential applications in
coastal areas, for coments on the use of lime for raising pH in combina-
tion with sea water, utilizing the magnesium as the flocculating agent.
Reply - Dr. S. Jenkins, who presented the paper in the absence
of his son, Dr. D. Jenkins, indicated that several important points were
raised, particularly by Dr. Weichers, on the kinetics of lime dissolution
and the kinetics of lime precipitation in particular. He suggested it
would be far better to have authoritative answer from the authors appear
in the proceedings. He did indicate one or two matters that he might be
able to deal with, as rather a bonus to the audience, because of particu-
lar concern with processes of this kind in the United Kingdom. At a con-
ference to take place in Johannesburg, South Africa, in June 1977, which
will be directed especially to chemical/physical approaches to wastewater
treatment and reclamation of water, an opportunity will be given for a
description of the facilities that are available in the United Kingdom
under the Department of the Environment. There are excellent facilities
for carrying out work on chemical/physical and also on biological treat-
ment of sewage at a large center at Coldhill, near Birmingham, United
Kingdom, as a part of a study by the NATO countries, and especially the
committee known as the CCMS Committee (Committee on Challenges in Modern
Society). The Department of the Environment also has work that is being
carried out on a smaller scale at Manchester, where a very highly indus-
trial sewage is being treated by a variety of chemical/physical processes
in combination with biological treatment. The importance of magnesium in
lime coagulation and the fate of organic substances are points that have
been raised by several speakers. It may be remembered that a process was
developed some years ago for the electrolytic treatment of sewage diluted
with sea water, and one of the features of the electrolytic process was to
produce a pH sufficiently high to force the flocculation of magnesium and
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the organic substances that are present in the sewage. Mr. Van Vuuren
referred to the possibility of the solubilization of suspended matter.
Jenkins expressed the opinion that he feels this is not an important
factor in the flocculation of sewage solids, sewage suspended matter,
by lime, if one assumes that the fate of any such solubilized material
would be the same as original organic substances present. The point that
Professor Molof raised concerning the characteristics of the sludge is an
important one, perhaps even a critical one. The effect of using lime as
a flocculant is to increase the yield of sludge by a factor of 25-50
percent at least. Usually it is found that the solids content of the
sludge obtained, under these conditions, also increases so that there is
what might be regarded as a compensating advantage of having a larger
yield of sludge but a sludge having a higher dry solid content. Never-
theless, Jenkins agreed with Professor Molof that in any complete study
of flocculation, it is necessary to take into account the yield of sludge,
the quality of sludge and its dewaterability.
C.2 Paper No. 40
Stumm (Switzerland). Objected strongly to the terminology used
in this paper on basis he did not think Wiechers had equilibria in any
of these systems, nor even pseudoequilibria. For determination of a
solubility product equilibrium should be attained from precipitation as
well as from dissolution data. The fact that Wiechers waited 24 hours is
not sufficient from a point of view of attainment of equilibrium. Fur-
thermore, Stumm commented, the solid phase or precipitate should have been
identified; was it an amorphous magnesium hydroxide, a calcite, a magnesium
calcite, etc. Weichers had discussed complexation solubilization of
calcium carbonates and magnesium hydroxide by organic matter in sewage.
Stumm indicated it was his opinion that organic matter in sewage would
not form complexes with calcium and magnesium to any significant extent
in these instances. Stumm suggested that the study actually dealt with a
kinetic phenomenon and, although kinetics are very important from a point
of view of practice, the data should not be interpreted in terms of "new
solubility products." Stumm recommended that detailed kinetics studies
on the nucleation and crystal growth of calcium carbonate and magnesium
hydroxide in such systems should be carried out.
Bristow (Australia). Asked the author to explain the effects of
ionic strength on the solubility determinations he carried out.
Platell (Australia). Indicated some factors that he thought
should be taken into consideration and which might affect Wiechers1 solu-
bility determinations. He noted that the reactions were carried out for
24 hours in air-tight containers which were constantly shaken and that
there would likely be gaseous environments above the liquid phase which
were somewhat different from an air environment. Further, the pH was not
actually measured in the solution while it was in the sealed container but
after the solution had been filtered. He questioned the potential effect
of aeration and C02 adsorption or release during filtration upon the final
solubility determinations. He also suggested that the potential buffering
capacities of organic acid radicals was not properly accounted for in the
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approach used by Weichers (calculating carbonate levels from measurements
of pH and alkalinity), and asked whether Weichers would consider the
determination of inorganic carbon by a total carbon analyzer to be a more
realistic measure of total carbonate species concentration.
Zoltec (USA). Questioned the use of Equation 12, Wiechers
definition of degree of supersaturation, suggested that he might consider
taking the nth root of that equation, where n is the number of molecules
in the crystal. As an example, he indicated that determining the degree
of supersaturation in this way to yield a number of 3 for calcium carbo-
nate would mean that you would have 3 times as much calcium and carbonate
as you would need, as predicted by equilibrium, whereas the number
obtained by the present equation would be 9. He suggested that this
might be a bit more intuitively meaningful. He also had some questions
on Figures 1-3; percent scatter for Figure 1 was listed as 1.12 percent,
for Figure 3 as 1.9 percent, and for Figure 5 as 2.05 percent. Zoltec
indicated he would think that the fit on Figure 1 is much poorer than
the other two and asked for clarification.
Weber (USA). Underscored what Stumm said about the substantial
difference between the kinetics phenomena apparently observed by Wiechers
and his interpretation of the data in terms of thermodynamic equilibrium
values. Weber suggested that in the 24 hour reaction time utilized, it
would be unlikely for thermodynamic equilibrium to be achieved. Weber
commented that he agreed that the organics in wastewater would not be
likely to form significant soluble complexes with calcium and magnesium
in that the coordination capacity of calcium and magnesium for the types
of organics that would be typical of wastewaters would not be very strong.
However, he noted there is another consideration that relates very
importantly to the fact that the solubility numbers determined by Wiechers
were not thermodynamic equilibrium values but rather kinetic intermediate
values; this consideration is that the types of organics that are present
in wastewaters will very definitely adsorb on precipitating nuclei and
markedly change the rate at which equilibrium is approached. This would
very definitely affect the non-equilibrium solubility numbers.
Reply - Wiechers indicated that the work he did, as stated, was
only for one effluent but Merrill and Jordan reported a summary of liter-
ature values for different effluents from which it was clear that as waste
strength increases the "solubility" products for these systems, determined
after some specified time, become greater and greater. The second point
raised by Parker was that of ion pairing effects. Wiechers agreed that
when studying this sort of effluent, when lime treated, ion pairing effects
are of consequence. Parker asked about correlations of the pK values with
COD and magnesium and in fact this was attempted. No significant correla-
tion could be found for these low COD effluents (20-40 ppm). Regarding
stability calculations using the tanglier saturation index, and the
Caldwell and Lawrence diagram, these diagrams are indeed not totally
adequate in explaining heterogeneous systems. Hiechers agreed with Stumm
and Weber regarding the use of the term "solubility product." He suggested
that the values he determined are in fact quasi-equilibrium values, not
solubility products but perhaps activity products for the specific systems.
On the question of organic matter complexing with calcium and magnesium
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Wiechers pointed out that this was only speculation and, as indicated in
the paper, this could not have accounted for the discrepancy between
calcite solubility constants and the actual values measured. Firstly,
the total organic matter concentration in the effluent was very low and
of this only about one-fifth is in a form which could possibly form com-
plexes with calcium. Adsorption of organics on precipitating nuclei and
reduction of rates of precipitation may have had an effect however, as
noted by Weber. Bristow asked about the effects of ionic strength.
Ionic strength will play an important role in determining true activity
products and it would be important to consider these ionic effects for
brackish wastes or other wastes of high salt content. Wiechers stated
that an attempt was made in the studies to minimize the effects referred
to by Platell, first, in the bottle itself by having as little air as
possible and filling it to the top; secondly, by doing the filtration
as quickly as possible and into a vacuum flask so that exposure to the
air was minimized. Relative to the question on the reliability of the
determination of carbonic or carbonate ion concentration by means of
pH and alkalinity calculations, the techniques used at present for total
organic carbon and total carbon are suitable for more precise determina-
tions but, according to Wiechers, they were not available when he did his
work and so he used the procedure he did realizing that it was subject
to some error. Again in the time required to reach equilibrium Wiechers
commented that after the paper was written he had a look at longer equili-
bration times ranging from 24 to 48 hours and, in one case, on the order
of 200 to 250 hours. He found that time does play a role - there is a
slight improvement in the pK values of the order of 0.1 or 0.2 of a unit,
but that this still did not bring the pK values into the range of those
predicted by the true solubility constants.
C.3 Paper No. 43
Marks (Australia). Regarding the lime required to reduce phos-
phorus to less than 1 mg/£, some research has indicated a dose of approxi-
mately twice the alkalinity or, in this instance, approximately 800 mg/t;
other research has indicated levels of 200-400 mg/£, directed primarily
at achieving a pH of 11.5-12.5, and magnesium hydroxide flocculation.
Some researchers have reported lime clarified sewage sludge volumes of 2
to 3 times that of biological sludges. This introduces a major disposal
problem. The figures in the original paper for total solids reduction
through the clarifier, coupled with lime dose, indicate a sludge produc-
tion of about 0.5 kg of dry solids per cubic meter of plant throughput,
indicating a sludge volume of 3-5 percent of plant throughput. What in
fact was the average sludge production? The paper indicates that natural
recarbonation reduces the pH in the polishing pond from about 11.5 to 10.5
in 9 days. Other researchers have indicated that it takes 20-30 days, in
moderate climates, to achieve a reduction from pH 11.5 to about 8 to 9,
normally required for discharge. Finally, there are some indications that
the calcium phosphate in lime sludges does not redissolve to any great
extent, even when the supernatant is recarbonated to neutral pH. Has any
of the work in Israel shown this to be so?
Wechsler (Australia). The water used for ground water recharge
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eventually will be used for domestic supply. It is disturbing that there
is the possibility that refractory soluble organics may pass through the
system, and may eventually appear in the drinking water supply. Also,
there will eventually be a salt buildup beyond which the water cannot be
used for domestic consumption. Wechsler claimed that it is not possible,
by analysis, to show that refractory organics do not exist and that one
must design around this problem. He indicated his thought that a plant
which maximizes the number of different processes for pollutant removal
is one which is going to give the widest cross section of removal and that
perhaps some process, such as reverse osmosis or activated carbon filtra-
tion, should be used when this water is withdrawn from ground water for
domestic consumption.
Bristow (Australia). Asked whether the authors had experienced
any algae problems in the stabilization pond and whether they have any
comment on algal growth control by the high pH. Also indicated surprise
at the pH level at which the water was discharged into the aquifer.
Uhlraan (West Germany). Asked whether the retention time of the
oxidation pond was selected on the basis of maximum BOD removal or maximum
suspended solids removal.
Shuval (Israel). Commented on the quality aspects of the reuse
water; indicated some might question whether such a high quality effluent
is necessary for agricultural reuse. Supported objective of aiming for
such high quality for agricultural reuse. High microbiological quality
will allow for unrestricted agricultural reuse. If there are pathogens
in the water, must restrict the type of crop. High microbiological quality
is necessary for the health of agricultural workers and residents of the
vicinity of application. High lime treatment does partially remove heavy
metals. The avoidance of heavy metals in the soils or possibly in the
agricultural products is a worthy goal, particularly in dealing with a
wastewater stream from a community of a million and a half people where
it would be difficult to control all industrial sources; also know that
many heavy metals enter the systems from domestic sources. As to the
possible ultimate use of such a water for domestic purposes, Shuval indi-
cated that preliminary tests he has carried out indicate that TOC's as
high as 10 can be detected in the recharged ground water; it is obvious
that such water would require additional treatment before it could be even
considered for drinking water purposes.
Reply - Regarding Wach's question about the distribution of sus-
pended solids, in the observation ponds essentially all the suspended solids
are organic. However, in the clarifier effluent as well as in the tertiary
effluent some of the suspended solids are calcium carbonates. Regarding
the possible clogging of the aquifer, the plans of this project are to add
C02 for stabilization purposes at the end of the last polishing pond. The
amount of carbon dioxide required here is estimated to be about 50 mg/£
instead of about 200 mg/£ if the carbon dioxide were added directly to the
clarified effluent, resulting in a savings of approximately 75 percent in
the amount of carbon dioxide required for recarbonation. As for the question
on winter results, the processes incorporated in this scheme are greatly
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affected by temperature. He indicated that since the paper was written
they have studied the pilot plant in winter conditions. There are some
marked differences between the summer and winter results (he did not
elaborate further). Regarding the lime dose required to reduce phosphate,
the alkalinity was about 300-400 mg/t as calcium carbonate and the lime
dose was about 700-750 mg/£, thus, a lime requirement of roughly twice
the alkalinity. As for the use of polyelectrolytes in conjunction with
lime, there is no reason why polyelectrolytes should reduce the lime
dosage since the lime dosage is mainly dependent on alkalinity and on the
pH required. However, they did try polyelectrolytes to improve performance
of the plant and effluent quality. Tested about 10-12 different polyelec-
trolytes but none were found to have any measurable effect. Conversely,
when magnesium chloride was added, even in very small amounts (5-10 mq/i),
there was a considerable improvement in clarification. Therefore, prefer
to use magnesium chloride rather than polyelectrolytes. Sludge is defi-
nitely a problem. In this type of operation, except for recalcining for
lime recovery, there is no other use that has been found for the sludge.
Sludge yields approach about 1 kg dry solids per cubic meter treated.
However, one advantage is that the sludge is much thicker than biological
sludges, about 8-12 percent solids. Thus, no thickening is required and
the sludge can be directly disposed of to drying beds for dewatering.
Regarding regrowth of algae in the polishing pond, this was experienced
only once, when the detention time was long (14 days). The pH dropped to
about 9.5. This is now avoided by having a detention time of about 9 to
10 days. On the question of refractory organics and the suitability of
this effluent for domestic reuse, he reiterated that the effluent is meant
for ground water recharge only. There are possibilities of using this
effluent, mixed with ground water, after it is pumped from the aquifer,
for domestic supply but only after treatment with additional water treat-
ment processes such as activated carbon and/or reverse osmosis. The exact
process requirements can be determined only after more information about
the quality of the recharged ground water is obtained.
C.4 Paper No. 46
Thorton (NZ). Indicated that in preliminary investigations on
the use of activated carbon for tertiary treatment they have found that
inoculation of the activated carbon filter with bacteria under aerated
conditions increased removal of soluble pollutants over that obtained
with non-inoculated systems.
Rincke (Germany). Reported observations that chlorination
reduced the efficiency of rapid sand filters and that preaeration had
positive effects on removals obtained. Indicated that he did not under-
stand why there was such a low oxygen demand in the filter, however. Only
1 mg of oxygen was reported to be needed for 10 mg of BOD eliminated but
this should be confirmed by including a measurement of the BOD of the
accumulated solids removed by backwashing the filters. Indicated it would
also be of interest to know whether any nitrification took place; this
could be determined from a nitrogen balance between the influent and efflu-
ent. The authors commented elimination of suspended solids in the filter
was better when the biological pretreatment was lightly loaded than when
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the pretreatment was heavily loaded. It is reasonable that the effluent
of a highly loaded pretreatment contained more biodegradable material which
promoted intensive growth of bacteria in the filter. Thus, the suspended
particles in the filter effluent may have been largely comprised of biomass
generated on the filter.
Benedek (Canada). Questioned the physical arrangement relative
to air entrapment in the filter; asked how this problem was avoided in
the downflow filter used. Asked also whether air scour was used in back-
washing the filters to remove residue.
Weber (USA). Referred to studies (Weber e£ o£.) reported approx-
imately 10 years ago describing the substantial growth of bacteria on
activated carbon in waste treatment applications. Noted Thornton's com-
ments that he had observed improved removals by activated carbon systems
when the columns were inoculated with bacteria. The significant point
is that bacteria will grow on any fine grained media and the objective
in developing a treatment scheme should be to provide optimum conditions
for this to occur. First, the consideration of the type of reactor is
highly important. Weber indicated that there are many advantages that
accrue with an expanded-bed type of reactor system and referred to the
results he presented on "Biologically Extended Physicochemical Treatment'1
at the 1972 IAWPR Conference in Israel and earlier papers comparing
expanded-bed and packed-bed reactors. Indicated that the expanded-bed
reactor was the type of system adopted by Jen's in the recent work referred
to by Eckenfelder. The second primary consideration for optimization of
this type of treatment scheme, Weber indicated, is the media on which the
biological growth is developed. He maintained that just as expanded clay
was found in the present investigations to be superior to sand, his
results give indications that activated carbon has marked advantages over
any other type of media. He cited a number of reasons for this. First,
activated carbon has a high affinity for molecular oxygen and, consequently,
provides a driving force across the biological film to bring the oxygen
more actively into the biofilm. Second, the principal partitioning factor,
or driving force, in a system in which sand or expanded clay is utilized
is the free energy for biosorption which is relatively low. In a system
in which the support medium is material such as activated carbon, the
partitioning factor is that of adsorption which has a substantially higher
free energy. Therefore, the sharpness of separation in the latter reactor
is much higher. The retention time then of the organics is controlled by
the retention time of the solid support media rather than the retention
time of the fluid media, a highly significant factor. Third, there are,
as has been pointed out in a number of discussions at this meeting, a
broad spectrum of organic materials which are not readily biodegradable,
such as chlorinated hydrocarbons, but which present very real problems
with respect to reutilization of wastewater. With activated carbon as a
support media, the dual function of adsorption of these materials from
solution and retention in the solid phase can be accomplished. One
further point - there is a potential advantage in some cases to allowing
the system to go marginally anaerobic rather than to try to meet the
total oxygen requirements for aerobic oxidation. One of the advantages
is the generation of a lesser amount of biological solids. One of the
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difficulties in such a system is that sulfates can be reduced to suflides
and cause some deterioration of effluent quality. This, however, can be
controlled by the admission of nitrate in the influent. The nitrate func-
tions as an alternative electron acceptor to the sulfate, producing nitro-
gen gas instead of sulfides. The performance of such a system is often
dependent upon controlling the accumulation of biological solids and, in
answer to the question raised by Professor Benedek of Canada, Weber indi-
cated that he had found that periodic air scouring is essential to the
maintenance of a thin, active biological film.
Reply - Several questions were raised regarding accumulation of
solids in the filter, backwashing and minimum oxygen concentration neces-
sary in the filter. The frequence of washing is a function of the quality
of the secondary effluent being treated on one hand and, on the other,
the acceptable headless across the filter. After a physical/chemical
process, for example coagulation with lime, on domestic waters, the fre-
quency of washing would be about every 24 hours with a permissible head-
loss of 1 m. There is a purification plant which has been operating on
this principle in France for 3 years with excellent results both in terms
of chemical/physical treatment and filtration with expanded clay. The
question of the minimum concentration of oxygen to be maintained in the
filter is quite difficult; indicated that his work suggested a minimum
concentration of 0.5 mg/£. Regarding Mr. Rincke's question about the
quantity of oxygen provided relative to BOD and COD in a tertiary filtra-
tion plant or after physical/chemical treatment, Faup indicated that he
observed that qualities of oxygen consumed were relatively low in relation
to quantities of BOD eliminated but could not really explain this. Regard-
ing Dr. Benedek's question on physical arrangement, several techniques
can be considered. Aeration can take place either above the filter or in
an independent basin. Indicated that he has never observed any problems
with air binding of the filter. Regarding the use of expanded beds with
activated carbon, Faup commented that there is the cost of the granular
media which must be considered and a question of the control of dissolved
oxygen in the air expanded-bed system. Suggested that oxygen input to a
downflow filter is not limited by expansion of the filter media but that
when working with an expanded-bed it may be more difficult to put in
exactly the right quantity of oxygen because of expansion of the filter.
Also asked whether there is a problem of higher suspended solids concen-
tration in the effluent from an expanded-bed filter than in that from a
conventional downflow filter. Faup asked if it would be possible for Weber
to comment further on these aspects.
Weber. Three questions were raised by Mr. Faup: 1) relative
cost, 2} control of dissolved oxygen addition to an expanded bed, and 3)
control of suspended solids in the effluent from an expanded bed. Regard-
ing first the question of cost, one has to look at functionality and the
cost effective utilization of a material. Activated carbon serves at
least two functions, whereas sand and, to a large extent, expanded clay
serve only one function. Activated carbon provides for adsorptive removal
of biologically resistant organic materials that would not be removed by
a sand or expanded clay. Carbon then serves an additional and very impor-
tant function in wastewater treatment; this markedly increases the cost-
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effectiveness of the activated carbon and usually justifies the additional
cost of the media. In such a system, biological activity is really a
secondary function of the activated carbon so the primary cost distribution
relates to the first function, namely the adsorptive removal of organic
material. The additional biological growth does in fact help to extend
the useful life of the carbon between regenerations and consequently mini-
mize the cost of an activated carbon system. It also provides for some
removal of organic fractions that are not strongly adsorbed. Weber indi-
cated no difficulties with respect to application of oxygen to an expanded
bed activated carbon system, nor to his knowledge of any physical difficul-
ties that had been experienced in the addition of air to expanded bed sand
filters. Indeed, he indicated oxygen transport to the biological surfaces
is facilitated and enhanced in an expanded bed system where all of the
surfaces, or a larger fraction of the surfaces, of the granular media are
available for transport. With respect to the suspended solids control,
most activated carbon systems are two stage systems. If suspended solids
control is a potential problem, one logical way to use such systems would
be to have the first stage adsorber operating in expanded bed mode and the
second stage adsorber operating in packed bed mode-
D. Other Observations and Comments
Most observations and comments are covered in the detailed
accounting of floor discussions given above. Of particular additional
note is the observation that the considerable interest displayed in this
session appears also to carry over to the forthcoming IAWPR Conference
on Advanced Treatment and Reclamation of Wastewater scheduled for South
Africa in June 1977. Many in attendance at this session indicated their
interest in presenting results of related studies at the Johannesburg
Conference. The integration of biological treatment systems with physico-
chemical treatment systems for advanced treatment and water reclamation
is clearly of international interest.
IV CRITIQUE OF SESSION
As indicated in D above, the papers of this session were generally
well received and aroused a substantial amount of interest and discussion.
The papers were not particularly original in concept or detail to those
who have been conducting active research in these areas but, since this
latter group is relatively small in size, the material was relatively
original to the majority of the participating audience. The quality of
the papers was generally acceptable although one or two, most notably
paper No. 46 by Faup &t cJL. , could have been much improved had the authors
been aware of and used the substantial body of literature and information
already available relative to the subject matter of the presentation.
The format of the session was excellent with only a brief summary
of the paper presented by the author and a considerable amount of time
allowed for discussion. In this regard, however, it is important that the
preprints be distributed sufficiently in advance of the meeting to allow
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participants time to read and review the papers of most interest to them.
With such a format, the role of the formal discusser becomes somewhat
more critical.
The disadvantage of the format, and this was changed in some
sessions, was that the speaker did not respond to the discussion until
all discussions (formal and floor) had been presented. This had an adverse
effect on continuity and resulted in several points being missed in the
response and/or lost out of context.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
In that physicochemical processes are becoming more and more
prevalent in the U.S. wastewater treatment technology and applications,
this session was one of the more pertinent sessions - relative to U.S.
pollution control problems - of the Conference. Of particular interest
is the possible integration of physicochemical process technology with
conventional (and not-so-conventional) biological process technology.
Advances in this area will have significant implications for simultane-
ously achieving higher degrees of treatment while maintaining reasonable
capital and operating costs for water pollution control, both in indus-
trial and municipal wastewater treatment. It would seem appropriate to
place a much stronger emphasis on developing and optimizing integrated
waste treatment systems.
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I. SESSION
A. Theme of Session: Stabilization Ponds
B. Papers Presented: 49. Recirculation Ponds - Pilot Plant and
Field Studies.
G. Shelef, M. Ronen, M. Kremer (Israel)
52. Seepage from Oxidation Ponds.
E. Idelovitch (Israel)
55. An Integrated High Rate Pond-Algae
Harvesting System.
J. C. Dodd, J. L. Anderson (Australia)
II. REVIEWER
A. Name: R. Addis Lockwood
B. Position and Affiliation: Assistant Professor California
State University
Northridge, California 91324
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 49
The major emphasis stated in this paper dealing with the opera-
tion of multiple stage oxidation ponds is on the effects of recirculating
partially treated effluent back to be mixed with the raw sewage influent.
Data from a full scale plant are presented showing the effect of the
recycle ratio, recycle rate/feed rate (R/F), on BOD^ removal in the first
three pond stages at two organic loading levels. Pilot plant results
showing the effects of R/F on the sulfide concentration in the surface
water of the first stage are given in addition to the effects on BODs
removal in this small two-stage prototype system. Much additional data
on algae counts and identification, COD, suspended solids, dissolved
oxygen, pH, and operating temperatures in various stages were also pre-
sented without specific correlation to recycle ratios. Finally, the
effluent from this plant (Dan River Region in Israel) is to be used for
long-term ground water recharge. During operation since 1969, the biologi-
cal treatment effluent has not met the quality requirements for this use.
A final sludge-blanket lime clarifier is to be used to finish the treat-
ment. The effluent levels of BOD, COD, TSS, nitrogen compounds, phosphate,
and detergents from a pilot plant clarifier operating with 3rd stage pond
effluent are tabulated together with the final quality following ponding
of this effluent for NH3 removal.
The most important conclusions reached were that recirculation
immediately solved the severe odor problem experienced during the initial
operation in 1969. The first pond, receiving raw sewage, was strongly
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anaerobic and considerable sulfide concentrations were present at the
surface. Recirculation of water with considerable DO from a later stage
pond satisfied the immediate oxygen demand and allowed normal reoxygena-
tion at the surface to maintain a sulfide-free top layer. A second benefit
of recirculation was found to be an increase in the aerial loading capacity.
The optimum R/F for maximum loading (about 400 kg/Ha-day) in this system
was found to be about 2/1, the recycle being 3rd stage effluent.
A.2 Paper No. 52
The subject of this presentation was the measurement of seepage
rates from the Dan Region treatment ponds discussed in the first paper.
Seepage was computed from a simple water balance in which the seepage was
the unaccountable portion after all other sources and sinks had been quanti-
fied and balanced. Two sets of ponds are compared - one without linings
and one set with compacted clay linings. The major conclusion to be drawn
from the data is that the unlined ponds (in this case constructed on sand
dunes) after a few years of operation approached the seepage rates of
clay lined ponds after a similar period of use. It was suggested that
the most important issue in the decision to line treatment ponds with clay
is the possibility of seriously polluting ground water during the early
months of operation of unlined ponds. The data showed that after four
years the seepage rates were quite stable in both systems, but still not
near zero. The latest seepage rates were reported to be 7-8 mm/day.
A.3 Paper No. 55
The two key elements in the algae harvesting system described
are: the control of the type of dominant organisms produced in an oxida-
tion pond with wastewater feed and the development of economical and
efficient filtration techniques. The input wastewater for the testing
described was the effluent from a primary treatment plant with "average"
BODs and COD of 405 and 733 mg/£, respectively. No data from the pilot
operation were presented but estimates of removal efficiencies for a full
scale system, based on pilot plant operation, were said to be in the range
of 90-95 percent for suspended solids and BODs- The high rate pond, much
resembling the Pasveer system or oxidation ditch, was lime treated to
raise the pH from near neutral to the range of 8.3 to 9 pH, which main-
tained the predominance of the more readily filterable Sc.e.nedeAmuA sp.
over the smaller ChZo/ieMa.. The separation of algae from effluent was
accomplished by vacuum filtration on a paper medium formed directly
beforehand on a continuous belt septum using the Fourdrinier process.
Most of the data concerned the separation of the algae solids from the
paper filter medium after filtration by a two-stage vacuum backwash where
the paper is supported in a belt sandwich by an auxiliary belt. The algae
pass through the auxiliary belt. Using the two stages of vacuum backwash
plus two stages of wash following repulping of the paper filter medium,
less than 1.5 percent of the algae remained with the pulp. Most of the
discussion is devoted to a description of a proposed full scale 100
megaliters/day (M£/day) plant with flow diagrams and cost estimates.
These show an estimated annual cost nearly one-third lower for the har-
vesting system than for an alternative "conventional" secondary treatment
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system using methanol as an auxiliary carbon source to attain denitrifica-
tion to the levels projected for the harvesting system. This estimate
depends on the recovery of nearly one-third the cost of plant operation
by sales of the algal product at $140/tonne ($200 market value). The
average crude protein content of the algae concentrate was 53 percent.
Heat treatment was proposed to destroy pathogens and improve the digesti-
bility of the product algae.
B. Prepared Discussions
B.I Mr. C. D. Parker from Australia suggested a possible connection
between the responses of both the pond system and trickling filters to
recirculation of effluent. In both cases the loading on a unit could be
nearly doubled by the use of recirculation. Experience with trickling
filters has indicated that concentrations above a maximum of about 100 mg/£
of BOD5 applied to the filter inhibits algal growth. Further work with
higher strength wastes is needed to develop design principles for recycling
pond systems that might be appropriate for industrial wastes with much
higher strengths, say 5 to 10 times those reported in these Dan Region
tests. If the requirement for influent BODs concentration of 100 mg/£ or
less really applied to ponds, 1500 mg/£ wastes would require a 15:1 recycle
ratio. The question of pumping energy in this case will be an important
trade-off against increased pond area to keep the loading down. The
reasons for the sulfide increase with "loading" in the pilot plant and
the type filter used in determining dissolved BOD5 were questioned. Dr.
Shelef responded that the reason for increase in sulfide with R/F, when
R/F = 2, is: sludge raised by turbulence. The suspended solids were
removed with Millipore membrane filters to determine dissolved BODs on the
filtrate.
On the matter of design for higher strength wastes, the author
agreed that something better than recirculation alone would be needed
because of the high pumping energy requirements. The upper limit for
economical pumping was stated to be about R/F = 3, while ratios above
6 result in operation of the whole system as a completely stirred reactor.
B.2 The discusser asked about water table conditions, depth to the
clay layer and sand size. The answers were that little change in level
was observed, with both the water table and clay lining at about 7-8 meters
depth. The sand was about 1 mm size. It was suggested that suspensions
of clay and/or silt might be employed with coagulants to seal the pond
bottoms before operation, to reduce the initial loss of polluted water.
B.3 Dr. Shelef discussed heavy metals in the product saying that
the mere presence of toxic metals, and BaJbnoneJLLa., does not define a prob-
lem. Lead in foods has been found in some cases to be directly eliminated
and not be assimilated. Only extensive feeding and inspection of the
flesh can define the scope of intoxication by contaminated feed. It was
also pointed out that under good conditions one hectare of algae pond can
produce 110 tonnes of dry algae per year; this is about 10 times the pro-
ductivity of soy beans, one of the highest yield high protein alternatives.
Prof. Oswald stated in his written discussion that the system may be too
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complex for developing countries where the trend should be towards
simplicity. Dr. Shelef described work in Israel on an algae recovery
with a simpler system using alum floe for separation by flotation fol-
lowed by acid washing, pH 3.5, to remove the aluminum and readily
soluble heavy metals. The product was successfully fed to chickens.
C. Floor Discussions
C.I The lively floor discussion centered on the operation of the
first stage pond and recycling. Step feeding was proposed as a superior
alternative to recycling. It was also proposed for augmentation where
very high strength wastes are treated. Auxiliary floating aerators were
also suggested for use in augmenting the reaction rates in the first
stage ponds. The point was made that some background is already avail-
able for designing the first stage pond. The first stage pond may be
considered as two cells, one anaerobic and one facultative - photosynthetic.
The depth of the first stage should be determined by the maximum anaerobic
sludge volume required'to digest the settleable solids. Month-by-month
calculations based on temperature (reaction rate) and mass balance have
been used by Dr. Oswald at the University of California-Berkeley to size
the anaerobic cell. The consensus of the group appeared to be that a great
deal more work is needed before the multiple stage pond treatment is well
understood. For example, is stratification a problem? It was stated
from the floor that stratification could result in serious short circuiting
(actual detention times 0.1 of those calculated). Dr. Shelef pointed to
the experience in Israel where the small pilot plant ponds stratified
daily but wind prevented stratification of the full scale treatment ponds.
A possibly significant advantage of using an anaerobic first stage is the
destruction of pathogens. Schistosomes were said to be destroyed in
anaerobic digestion if their detention time is sufficient.
C.2 An experience with a pond in sandy soil was described in which
the extremely high infiltration rate did not change over an eight-month
period with an influent with much higher solids concentration than the
Dan Region water. It was suggested that the high pH may have led to
precipitation of solids to block the interstices.
D- Other Observations and Comments
The general response of a number of Australians to the two
papers on pond lining and algae recovery was rather critical. The con-
sensus was that pond lining is still very much an unresolved problem.
For example, both butyl and hypalon have been used. Fatty acids attack
hypalon. One lagoon lining developed hundreds of methane bubbles in one
year which were lanced like boils to relieve the pressure. The algae
recovery project has been extensively examined by the Bureau of Studies
of the Department of Housing and Community Development in a yet unissued
report titled "Planning for the Use of Sewage." A. 6. Strom, Director
Civil Engineer, stated they have found this system too expensive and are
concerned about pathogens in the product.
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IV. CRITIQUE OF SESSION
The presentation of operating and descriptive data for the Dan
Region pond system brought interested response with much floor discussion
of the first two papers. The value of the exposition of this technology
for low energy treatment is probably best illustrated by the difficulties
encountered in operation of this plant in 1969-70 shortly after start-up
without recirculation although two similar systems were already operating
with recirculation in other countries 10 years earlier. The amount of
data shown represents only a tantalizing beginning. Variables such as
pH, temperature, dominant microbe population, suspended solids, and DO
were reported but not correlated to recycle ratio or BOD removal. Pond
configuration details such as inlet and shape for flow control and depth
cannot be optimized without much more study. Enough has already been done
to point the way to successful, if not optimum, designs for pond treatment
of raw sewage. The report on seepage will not be much help in designing
pond seals.
The separation of algae using an in. &
-------
worth $1.00/kg - but much easier to harvest. The textbook viewpoint
of sewage as a nuisance in the 60's and the admonition to use energy to
subsidize processes to reduce capital costs is rapidly changing to the
idea that the nutrients are a resource to be recovered and energy con-
servation is imperative, at least for the next decade or two. Present
information suggests that economical pond systems with biological treat-
ment have potential to produce superior effluents at low cost in energy,
or even a net gain, counting solar input to produce food products.
Research is needed to learn how to control the growth of destructive
organisms such as some of the cyanophytes (Keating, 1976) while promoting
the growth of desirable species. It is not now clear if or when vascular
plants (bullrushes, etc.) or animals such as brine shrimp or fish should
be used. There are pro (McKinney, 1967) and con arguments about the role
of micropredators (rotifers, voricella, etc.) as well as the symbiotic
relations between the algae and bacteria in using and producing oxygen
(Bartsch, 1957). Answers to these questions are needed before system
optimization to meet water quality requirements for reuse becomes a science.
REFERENCES
Bartch, A. F. and Allum, H. L., "Biological Factors in Treatment of Raw
Sewage in Artificial Ponds," Umnol. and Oceawog., 2, 77-84 (1957).
Carpenter, R. L., Coleman, M. S. and Jarman, R., "Aquaculture as an
Alternative Treatment System," in Biological Control of Water
Pollution, J. Tourbier and R. W. Pierson, Jr. (Eds.), University
of Pennsylvania Press, 215-224 (1976).
Dinges, R., "A Proposed Integrated Biological Wastewater Treatment
System," in Biological Control of Hater Pollution, J. Tourbier
and R. W. Pierson, Jr., (Eds.), University of Pennsylvania Press,
225-230 (1976).
Halvorson, H. 0., "The Use of the Oxidation Ditch in the United States
as a Means of Treating Liquid Waste," in Biological Control of Water
Pollution, J. Tourbier and R. W. Pierson, Jr. (Eds.), University of
Pennsylvania Press, 253-258 (1976).
Keating, K. I., "Interference by Blue-Green Algae with Nutrient Recovery
in Water Quality Control Scheme: Management Implications," in
Biological Control of Water Pollution, J. Tourbier and R. W. Pierson,
Jr. (Eds.), University of Pennsylvania Press, 241-244 (1976).
McKinney, R. E., "Microbial Relationships in Biological Wastewater Treat-
ment Systems," in The Structure and Function of Fresh-Water Microbial
Communities, J. Cairnes, Jr. (Ed.), Research Division Monograph 3,
Virginia Polytechnic Institute and State University, Blacksburg, VA,
165-180 (1969).
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I. SESSION
A. Theme of Session: Sulfide Attack on Sewers
B. Papers Presented: 38. Simulation of Design-Storms with Probable
Distributions in Time and Space for
Storm Drainage Systems.
F. Sieker (Germany)
41. The Significance of Stormwater Runoff
in an Urbanizing Watershed.
C. W. Randall, J. A. Garland, T. J.
Grizzard, R. C. Hoehn (USA)
44. Prevention and Protection of Sewerage
Systems Against Sulphide Attack with
Reference to Experience in Singapore.
A. Nadarajah, J. Richardson (Singapore)
47. The Forecasting of Sulphide Build-up
Rates in Sewers.
R. D. Pomeroy, J. D. Parkhurst (USA)
II. REVIEWER
A. Name: Ivan L. Bogert
B. Position and Affiliation: Partner, Clinton Bogert Associates
Fort Lee, New Jersey
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 38
This paper provides a method of developing the design storm for
storm drainage systems from rainfall data. The design storm intensity
may vary with time and space.
Most drainage systems are still designed by the rational method
for a design storm of a specified duration and return frequency. The
design storm has a uniform distribution of rainfall in time and space.
It implies that the frequency of rainfall is equal to the frequency of
runoff. This is incorrect in reality since rain storms of the same dura-
tion and the same amount but with different storm patterns will result
in different peak and distribution runoff.
The proposed method analyzes point rainfall data at several
rain gauges using a multi-variate statistical technique of variance
analysis. While the total amounts of rainfall at a given station point
are independent from rainfall event to event, the method considers time-
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dependence and space-dependence of rainfall within a given rainfall
event. Irregularity of rainfall is expressed in terms of components
which are evaluated. These are developed with respect to time in three
factors - mean distribution in time, exceedance probability factor, and
random factor (which cannot presently be defined). The distribution in
space is defined by five factors - mean distribution in space, exceedance
probability factor, drift factor due to winds (occurs in strips), anti-
drift component (which is not defined physically), and a random factor
(which also cannot be defined physically).
The design storm is corrected by the ratio of the average
rainfall depth obtained from a frequency analysis of the total rainfall
amounts and the amount of simulated design storm.
The speaker indicated that some of the equations (bottom of
page 515 original paper) have been corrected and simplified since the
paper was prepared two years ago.
A.2 Paper No. 41
Field samplings were made during and after rainstorms with
depth ranging from 0.3 to 0.8 in. at selected locations of varying land
use types. The sample analysis shows that 1) organic concentration in
runoff approaches that of secondary sewage treatment effluent, 2) urban
runoff contains far greater loadings of suspended solids, organic matter
and nutrients entering the stream than a secondary treatment plant efflu-
ent; and 3) more diversified urban area produces considerably more pollu-
tant loading per unit area of all pollution parameters than a single
family residential area.
The data indicate that non-point sources must be controlled or
additional organic removal at treatment plants cannot be justified. The
amount of nitrogen and phosphorus removal which can be justified at
treatment plants is now being studied.
A.3 Paper No. 44
This paper deals with hydrogen sulfide problems in general and
with Singapore's case history in particular. Temperature is particularly
important to the incidence of sewer corrosion which is far greater in
tropical and subtropical areas than in temperate areas.
The paper describes the precautionary measures against hydrogen
sulfide attacks as 1) "prevention" by designing a sewerage system and con-
ditioning its environment to forestall the onset of septicity, and 2) as
"protection" by constructing the sewer with corrosion-resistant materials.
An example of the corrosion problem in the Singapore Sewerage
System is a 13 mm (1/2 in.) thick lining, of high aluminum cement mortar,
in an 1800 mm (71 in.) diameter concrete pipe which was completely cor-
roded after 9 years in use.
The experience on which the paper is based is related to
Singapore's conditions, i.e., material availability, expertise, and last,
but not least, economy.
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A.4 Paper No. 47
This paper discusses three formulas for estimating sulfide
build-up in filled pipes and points out that predictions in partially
filled sewers are much more complex. Based on studies at Los Angeles
County Sanitation District, it was believed that a complete equation
to estimate sulfide concentration could be established, based on the
factors involved. However, obtaining all the data is not practicable
because much data cannot even be obtained. Therefore, a simpler equation
is presented only related to those conditions where BOD, DO and sulfur
concentrations are most favorable to the generation of H2S. These
restrictions inherently result in the equation giving conservative
values. Consequently, the equation becomes useful in engineering where
the worst sulfide conditions need to be known in sewer system design.
The model represents the rate of change of sulfide concentration
as the sum of the input from the slime layer determined from BOD and
temperature, minus the losses due to oxidation rate and HgS volatilization
determined from the sewer energy line slope, stream velocity, mean
hydraulic depth and existing sulfide concentration.
B. Prepared Discussions
B.I Paper No. 38 - Sueishi, T. (Japan)
a. This method appears to be usable in all situations and
would be most valuable when used in connection with computer discharge
methods.
b. It was noted also that overflow possibility is greatest
when the rain clouds are moving in the same direction and speed as flow
in the sewers.
B.2 Paper No. 41 - Parker (Australia)
a. Are there any overflows or small industries into this
drainage system?
Reply - The system is all separate sewers with little industry
but some shopping centers.
b. Would settling of storm runoff significantly affect
nitrogen and phosphorus?
Reply - Yes; it would also affect the TOC.
c. Are there any agricultural runoffs into streams of this area?
Reply - All runoff is from urban areas. Upstream hydrograph,
which has some rural areas, did not change during this particular storm.
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d. The validity of using a single storm episode to calculate
annual figures was questioned.
Reply - Since the average storm during a year is about 0.45 in.,
it appeared that the use of the particular storm, which averaged 0.51 in.,
was reasonable as a starting point for studies.
B.3 Paper No. 44 - Hall (South Africa)
a. They have found liners not generally adequate but
corrosion-resistant pipes more suitable. An alternative would be to
use dolomitic aggregate with a sacrificial layer. For tunnels use
dolomitic aggregate concrete.
b. Spun pipe with silicious aggregate did not hold up.
c. They also use brick liners where turbulence occurs.
d. Inquired what has been done to protect joint material.
Reply - Top wax resin coats over cement joints were placed after
construction.
B.4 Paper No. 47 - Eden (U.K.)
a. There are problems in the United Kingdom but most in
rising (force) mains. They are using oxygen to combat this, using 7 kg
per week in the smaller ones and 9 tons per week in the larger ones.
BOD reductions were quite significant.
b. Has effect of nitrate been considered?
Reply - Nitrates may prevent H2S formation. In sewers, no
effects were found initially but appeared in two or three days.
c. Basis of assumptions on sulfide buildup and oxygen con-
sumption rates appear questionable and based more on empirical comparison
with results.
Reply - Many assumptions were determined theoretically by
Dobbins and checked by them empirically.
d. Feels figures in Figure 2 (original paper) are too high
and that, in practice, no buildup occurs in many cases where buildup
is predicted by formulas.
Reply - Buildup occurred for them.
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C. Floor Discussions
C.I Paper No. 38
Cosgrove (Canada). Postulate used in sewer system design to
date (and retained by the author) that rainfall frequency equals discharge
frequency does not hold. An example was given where an upstream moving
storm resulted in 4-hour discharge time while a downstream moving storm
of the same character resulted in 3-hour discharge time. Therefore, each
would have different hydrograph shapes and peaks.
Reply - This matter is still open and not intended to be covered
by the paper. Studies had not gotten to a point of combining time with
space distribution. Also, complete variations for a 6-hour storm would
cost $10,000 in computer time. In addition, there are measurement prob-
lems since recorders frequently malfunction and can be a quarter or a
half hour out, which completely changes the nature of the analysis. A
system to provide simultaneous plotting of records on one chart may
help in this respect.
C.2 Paper No. 41
Sueishi (Japan). Their data on pounds per day today are similar
to those produced in this report.
Comment from participant from Norway. Method of calculation of
averages appears to be on the high side.
Perry (U.K.). They find a large difference (particularly in
oil content) based upon the length of time prior to the storm at which
the last prior storm occurred.
Barnes (Australia). Have lead levels been checked?
Reply - Lead and iron are very high; also, there are other metals
in significant amounts.
Van Rooyen (South Africa). To what extent are toxic blue-green
algae present?
Reply - They are present in late fall. There are taste and odor
problems which they use copper sulfate to correct.
Are toxins removed by water plant?
Reply - No, better methods of water treatment are required,
however, rather than more advanced sewage treatment.
Participant from South Africa. Wouldn't more use of automatic
samples have been worth the cost?
Reply - Have now gone to automatic equipment for further studies.
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C.3 Paper No. 44
Cosgrove (Canada). Proper maintenance is essential no matter
what the construction. Can anyone report on lined pipe problems with
newly designed, properly maintained sewers?
Reply - In the East, toilets are not flushed as frequently as
they are in Western countries. Accordingly, sewage becomes septic earlier
and there are greater problems in these sewers even when properly maintained.
Browne (Australia). Is the reference to asbestos-cement pipe
that does not hold up, high pressure autoclave steam cured pipe? They
have found this gives superior resistance to pH of 4.
Reply - Yes, it is high pressure pipe. Also, would be more
resistant to pH since there is less concrete, 50 percent in the high
pressure pipe compared to 83 percent in regular A.C. pipe.
Goleb (Australia). There is some evidence that old sewers not
previously exposed to acid conditions were more resistant when exposed
to acid conditions than new sewers.
Parker (Australia) In many systems, as flow builds up,
problem diminishes.
Reply - Yes, but has been high in their case.
There should be more investigation into the chemistry of cement.
They also found older sewer sections more resistant than the new ones.
Shaw (Australia). Feels that approach of this paper is accepting
the hydrogen sulfide buildup rather than attacking it. Suggests use of
pure oxygen and counter current treatment which can build up 20 ppm oxygen
which would last for perhaps 10 miles. Studies of the rate of fall of BOD
after oxygenation indicate it would also result in pretreatment benefits.
In fact, they estimate that secondary treatment can be carried out in a
sewer system at a cost of $0.05 per thousand Imperial gallons.
Reply - As stated before, in many cases sewage is already septic
before it gets into the sewer and, accordingly, hdyrogen sulfide is present
at the time it enters the sewer.
C.4 Paper No. 47
Barnard (South Africa). Should distinguish between turbulence
before septicity which is good, and after sewage it becomes septic, which
is bad.
Reply - Yes.
Lovell (Australia). It would be desirable to gather information
for a curve on critical grades for various size pipes.
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Parker (Australia). Sulfate content of water supply should also
be considered.
Roberts (U.K.). Feels equations are generally tied to average
conditions and do not reflect extreme conditions.
Reply - Need to consider these special conditions as a separate
matter.
Recommends construction of house connections at the same time
as laterals to eliminate initial low flow conditions.
Suggest a special conference on the subject of sulfide in sewers.
Participant from Germany. Agrees on the need for special con-
ference. There has been an increase in Germany over the last few years
in sulfide problems.
D. Other Observations and Comments.
None
IV. CRITIQUE OF SESSION.
In general, the four reports were well received. The papers
were all high quality and were of matters of interest. Comments on
specific items with regard to certain papers are listed in Section V.
Although the method (Paper No. 38) appears to provide a logical
derivation of design storm using rainfall data, there are other practical
methods being used to derive a design storm for storm sewer design. These
practical methods are developed as the result of increasing use of the
hydrograph method instead of the rational method for storm drain design.
The hydrograph is arranged so that it conforms at all points to the
applicable intensity-duration curve which is readily available from the
U.S. National Weather Service publications. The time of peak rainfall
within the design storm is determined from analysis of observed rainfall
which is generally classified as having an advanced, intermediate, or
delayed peak. Storms of intermediate and delayed patterns produce greater
runoff rate and volume than storms of advanced pattern. These methods
are simple to apply and are widely used in the U.S.
The proposed method requires the digitization of rainfall data
in short intervals (as short as 5 minutes) for many years of observation.
The U.S. National Weather Service can readily provide hourly data for
most weather stations. To obtain shorter interval data, however, special
service is required.
Although limited samples were collected, the study findings
(Paper No. 41) are consistent with storm water runoff studies conducted
in other U.S. urban and semiurban areas, such as Philadelphia; New
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Brunswick, NJ; and Durham, NC; etc. These findings point out the needs
for comprehensive water quality planning of both point and non-point
sources. These needs have now been generally recognized. The ongoing
208 area wide wastewater management study in many parts of the country
aims at achieving such a goal.
There is no critique of Papers No. 44 and 47 other than as
given in Section V.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Paper No. 38 covers a matter of considerable importance to U.S.
water pollution control problems. The proposed method, however, appears
to be proceeding in a direction of considerable complexity and, to
evaluate the method for practical application, would require a comparison
study using the proposed method and the methods presently used. In such
comparative studies, one should also keep in mind that there are many
other factors affecting the storm drain design, including the concept of
using storm drains for pollution control.
Paper No. 41 is of considerable importance to American water
pollution research and construction activities due to the serious question
raised regarding the cost effectiveness of expending considerable sums
for more advanced waste treatment at sewage treatment plants without con-
sidering in the balance the effect upon the receiving waters of non-point
sources, as well as combined storm drain discharges. Further research
and studies should certainly be carried out into the effect of storm
water runoff, not only from point sources but non-point sources, both
from urban watershed and other types of watersheds, to determine more
accurately the effects of same upon receiving waters. Studies should
also be carried out of a procedure for economic and environmental evalua-
tion of such sources of pollution, together with the pollution from sewage
treatment plants.
Paper No. 44 presents a more extreme case than is usual in most
areas of the U.S. and the differing economic conditions would also affect
the comparative cost-effectiveness of providing protection against sulfide
attack. Certainly further research could be carried out under conditions
applicable to areas in this country.
In addition, floor comments regarding the higher resistance of
older installations certainly warrants further research in this area.
Further, of the linings considered for the Singapore sewerage
pipes, the resin impregnated terylene lining is of most interest. The
lining is formed by the introduction of a terylene fiber blanket into
the sewer, impregnating it with resin and forcing the blanket against
the sewer wall by pneumatic or hydrostatic pressure until the resin sets.
The resulting lining, which can be from 5 mm (3/16 in.) to 15 mm (1/2 in.)
thick, is rigid and self-supporting. Further investigation appears warranted.
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Paper No. 47 is important as the basic determinant of whether
a sulfide problem does exist or will exist. It would appear, however,
that further studies should be carried out on this matter to be able to
evaluate not only the extreme conditions presented, but also average
conditions which would be important in evaluating protective measures
versus use of sacrificial layers or of chemicals to counteract the sulfide.
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SESSION
A. Theme of Session; Automation and Aerobic and Anaerobic Digestion
B. Papers Presented: 50. Current Status>of Research in Automation
of Wastewater Treatment in the United States.
J. F. Roesler, D. F. Bishop, I. J. Kugelman
(USA)
53. A Comparison of Pure Oxygen and Diffused
Air Digestion of Waste Activated Sludge.
D. B. Cohen (Canada)
56. The Dynamic Behavior of an Anaerobic Digester.
A. D.'Carr, R. C. O'Donnel (South Africa)
II. REVIEWER
A. Name: W. Wesley Eckenfelder, Jr.
B. Position and Affiliation:
Distinguished Professor of Environmental
and Water Resources Engineering
Vanderbilt University
Nashville, Tennessee 37235
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 50
The first paper reviewed the current status of research in
automation in the United States. From the paper it is apparent that the
application of automation to municipal wastewater plants has seriously
lagged in design and construction of large treatment plants. While
several reasons were cited in the paper the paramount ones were: a) lack
of suitable models to base the control mechanisms on, b) lack of reliable
sensors, and c) lack of trained personnel to operate and maintain such
equipment. The USEPA has initiated a program to overcome these deficien-
cies through a newly organized Advisory Committee on Instrumentation and
Automation for Wastewater Management. It was further brought out in the
paper that a significant cost effective impact or improved effluent
quality control needs to be defined to justify widespread use of such
controls.
A.2 Paper No. 53
The second paper was "A Comparison of Pure Oxygen and Diffused
Air Digestion of Waste Activated Sludge," by David B. Cohen of Canada. The
paper developed several pertinent points, namely that sludge dewaterability
by vacuum filtration was improved after air digestion of dilute sludge, but
adversely affected by oxygen digestion of thickened sludge, that the maximum
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effective loading for diffused air digestion was a loading rate of
0.08 IDS VSS/ft3/day. Oxygen digestion was successfully accomplished
at loadings up to 0.433 Ibs VSS/ft3/day. An open tank oxygen diffusion
system was used in this study. The authors conclusions would indicate
advantages for oxygen digestion due to the ability to digest thickened
sludge resulting in reduced space requirements and higher digestion
temperatures from exothermic heat. This would be offset in some cases
by increases in chemical conditioning dosages to obtain equivalent
vacuum filtration performance as compared to air digestion.
A.3 Paper No. 56
The third paper discussed the application of a mathematical
model to the prediction of changes in anaerobic performance. The paper
itself used a theoretical model developed by the senior author with a
synthetic substrate under controlled operating conditions. Agreement
between prediction and response in most cases was good.
B. Prepared Discussions
B.I W. Von der Emde presented the prepared discussion on Paper
No. 50. In discussing the municipal wastewater treatment plant at
Blumental, Vienna, he showed that a variety of automation and control
had been in effective use for a number of years. This includes storm
water control through the use of the sewer level sensors (Roesler
-------
have significantly less degradable VSS present and overall VSS reduction
for any time-temperature relationship would be less. Failure to consider
this factor could lead to misleading conclusions. The paper provides
useful information on the application of aerobic digestion but the limita-
tions relative to the equipment used and the mode of operation must be
considered in any field application.
B.3 The formal discusser, H. Schoenfelder of the Federal Republic
of Germany, discussed municipal sludge digestion practices in Germany
which did not relate to the paper.
C. Floor Discussions
C.I The floor discussion primarily related to the need for operator
training in the use and maintenance of instrumentation and controls. In
addition, more technical training is essential on the mechanisms of
wastewater treatment in order to develop an understanding of control
response and adjustment. It becomes evident to the writer that a number
of actions need to be initiated or continued (some of these are already
in a formative or functioning stage):
1. Practical models defining the various stages of the wastewater
treatment plant need to be developed and field tested. Over
the years many models have been professed particularly for
biological wastewater treatment processes such as the activated
sludge process. Few, if any, of these have been adopted by
either the design engineer or the plant operator. The primary
reason is that the models are too complex, require knowledge
of parameters and coefficients that are not obtainable in the
real world, and were developed on known substrates under con-
trolled conditions which do not reflect field conditions.
2. The operator's professional status and resulting salary level
needs to be established particularly in the municipal field.
While certification has helped this situation over the years,
a large gap still remains in most cases between the professional
competence needed to perform the job and the salary levels
offered.
3. Training courses or programs to provide the technical knowledge
needed to understand and interpret the complexities of the
wastewater treatment processes are necessary. While many
operator training programs are available, few of these provide
the depth of technical understanding needed to effectively
operate under optimum conditions the increasingly complex and
sophisticated wastewater treatment plants of today and the
future.
C.2 An interesting point was made in the floor discussion of Paper
No. 53. The author noted a significant reduction in invertebrate biomass
in the oxygen digester, possibly due to crowding in the oxygen digester
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and the higher operating temperatures. Rincke confirmed from studies in
Germany that thermophilic aerobic digestion reduced or eliminated protozoa
and rotifers but that thermophilic digestion followed by mesophilic diges-
tion reintroduced invertebrates to the system with resulting improved
dewatering characteristics. Based or the paper and the discussion, this
writer arrives at the conclusion that additional work is needed to define
both the engineering and process characteristics of aerobic digestion.
While much of this information is presently available, a logical correla-
tion of such information is needed and a defined program for additional
studies developed.
C.3 The floor discussion (Paper No. 56), while not relating directly
to the paper, opened a major philosophical issue. Both Alan Molof of New
York University and D. Wexler of Canada raised the issue of the practi-
cality of such a model to engineering application and practice. The author
conceded that many of the parameters in the model could not be measured
or defined in practical application. Dr. E. Pearson of the University of
California defended the model approach as leading to a greater understand-
ing of the mechanisms of the anaerobic process. As a conclusion to this
discussion the writer feels that a major portion of the research generated
in universities and research institutes is esoteric and, while providing
advanced degrees to students, is not useful to the practitioner in the
field. It would seem that the question should be raised in a paper such
as this - how can this be applied to practice or, if not directly, what
additional research would be needed to make the results useful. These
observations apply, of course, to much of the research presently being
conducted in this field.
IV. CRITIQUE OF SESSION
This session was a "mixed bag." The first paper on automation,
while not a research paper as such, defined a need and research objectives
to attain. As such it is very useful to all researchers in this area of
activity. The second paper on aerobic digestion provided interesting and
useful information but must be interpreted with caution. A more compre-
hensive analysis of the problem is needed before meaningful engineering
conclusions can be drawn. The third paper on anaerobic digestion pro-
vided a theoretical analysis of anaerobic dynamics. While the response
to controlled and known substrate conditions was good, application to the
real world is questionable.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Aerobic digestion is widely used in the United States and design
practice and economics is very important to present and continuing water
pollution control programs. The paper suggests needed areas of research.
The paper on anaerobic digestion suggests needed research in the conversion
of theoretical models to engineering practice.
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I. SESSION
A. Theme of Session: Industrial Wastewater Management
B. Papers Presented: 39. Fellmongery Waste Treatment - Comparison
of Cost and Degree of Treatment.
H. Melcer, P. N. McFarlane (New Zealand)
42. Treatment Alternatives for Wastewaters
from the Tapioca Starch Industry.
M. B. Pescod, N. C. Thanh (Thailand)
45. Process Design Investigations for Alaska
Pulp Mill Wastewater Treatment Facilities.
H. Edde, R. French, 0. Mason, T. Hosoi
(USA)
48. Measurement and Treatment of Oil and
Grease in Petroleum and Petrochemical
Industrial Wastewaters.
L. F. Tischler, R. L. Elton,III,
D. L. Ford (USA)
II. REVIEWER
A. Name: Carl E. Adams, Jr.
B. Position and Affiliation: President, Associated Water and
Air Resources Engineers, Inc.
P. 0. Box 40284
Nashville, TN 37204
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 39
This paper gives the cost-effectiveness of treating wastewater
in New Zealand. Three methods were discussed: catalytic oxidation,
bio-filtration with a trickling filter, and an aerobic lagoon. The
characteristics of these wastewaters after treatment by these three
methods are shown in Table 1.
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Table 1
Parameter*
BOO
COD
Total Solids
Suspended Solids
Total Nitrogen
Total Sulfide
PH
Raw
Effluent
2,000
3,600
11,000
1,000
400
200
11.5
Catalytic
Oxidation
Effluent
— —
2,100
__
310
--
0
11.5-12.0
Bio- Filter
Effluent
1,200
2,000
__
—
1.0
--
10.0
Lagoon
Effluent
133
850
4,600
600"
1.0-10.0
7.9
— -
*
Units in mg/£, except pH
The following is a summary of capital and operating costs:
Table 2
Method of Treatment Capital Cost Annual Operating Cost
Catalytic Oxidation $135,200 $44,600
Bio-filtration 85,000 2,900
Anaerobic Lagoon 62,500 700
The plant described mixes concentrated dehairing and liming
wastewaters with the very concentrated soaking and deliming water. As
a result of this practice, the sulfide concentration in the wastewater
is sufficiently diluted (200 mg/£) so that the stream may be treated
biologically with no sulfide toxicity problems. In all the systems it
was assumed that adequate screening and sedimentation preceded the basic
treatment unit. Equalization was provided for catalytic oxidation and
bio-filtration; however, the anaerobic lagoon was so large that equali-
zation was not required. Cost information was taken from reference
tables.
The catalytic oxidation scheme employed KMn04- In the U.S.
manganous sulfate is often used because it is more economical. However,
in New Zealand the price of these two chemicals is similar and, therefore,
the more efficient KMn04 is used. The manganese/sulfide ratio was selec-
ted at 1:10 and an aeration time of 15 minutes was used, based on liter-
ature values.
•3
The bio-filter was assumed to be loaded at 5 to 6 nr/day and
a recycle ratio of 8:1 was used. The pH dropped through the bio-filter
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to 9.0, while the catalytic oxidation pH remained high, in the range of
11.5 to 12.0. The organic concentration in the effluent streams from
catalytic oxidation and bio-filtration was very high and, consequently,
additional treatment would be required in order to meet an acceptable
effluent for direct discharge to a receiving water.
The anaerobic lagoon was designed using a depth of 2 m and
70 day detention time. No equalization was required. Approximately
93 percent BOD removal, 76 percent COD removal, and 97 percent sulfide
removal was observed in a full scale plant. The sulfide removal results
were almost as good as the catalytic oxidation effluent. However, the
organic removal in the anaerobic lagoon was much superior to the other
two systems. The sulfide reduction occurred by purple sulfur bacteria,
Cktonwtfctaccae. The red color in the effluent was produced but no odor
problems were observed during three years of operation.
The conclusions of this study were that the anaerobic lagoon
is the only alternative for adequate treatment of sulfides and organics.
However, sufficient land is needed and the climate must be suitable to
provide sunlight since the Cktom&fctaceae are photosynthetic. If land
availability is a problem, the bio-filtration is best. Continuous cata-
lytic oxidation is not considered economically feasible. It is only
satisfactory for low volume, high concentration wastewaters which is
not the case in New Zealand. Catalytic oxidation systems offer the
best operational control, however.
A.2 Paper No. 42
This paper presents a summary of the tapioca starch production
in Thailand. Two types of wastewaters are generated, depending on the
quality of starch which is produced. The authors recommended that the
production waste be separated from the wash water used to clean the
tapioca plant roots before being crushed to generate the starch, and
that anaerobic treatment be used for first-stage treatment in most cases.
Next, the following stages may consist of a series of anaerobic ponds
followed by an aerobic aerated lagoon or bio-filter. If land is avail-
able, it is possible to follow the anaerobic facultative ponds in series.
Two stages of facultative ponds are recommended. If land is limited,
the anaerobic ponds followed by the aerated lagoon or bio-filter are
recommended. If only an aerated lagoon or bio-filter is used, it
should be preceded with primary sedimentation.
The authors also briefly examined single-cell protein produc-
tion using Tatu&i yeast. COD reduction of 73 percent occurred and the
yeast mass contained approximately 50 percent protein with 0.5 kg yeast
produced/kg COD removed. A nitrogen supplement was required on the order
of 1 kg nitrogen/50 kg COD removed. The effluent from the yeast produc-
tion required additional COD removal; because of this it is not considered
feasible.
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A.3 Paper No. 45
This paper presented a comparative study of air versus pure
oxygen activated sludge treatment of a dissolving acid sulfite pulp mill.
It also examined two in-plant options for generating waste streams for
treatment in the activated sludge system. One option was to treat the
total mill stream, while the second option considered bypassing directly
to the chlorination stage of the bleached plant effluent and treating
the remaining stream in the activated sludge system.
The authors recommended that the complete mix design was as
adequate a treatment as multi-stage or contact stabilization activated
sludge systems. Therefore, their studies were oriented toward completely
mixed activated sludge. They also concluded that the COD method for
determining oxygen requirements was more accurate than the oxygen uptake
measurements and, therefore, used the COD method in their comparison.
The pure oxygen system required 2 to 3 percent more oxygen than the air
system. The pure oxygen sludge thickened 50 percent better than the air
(44 vs. 30 Ib/sq ft-day on a mass loading basis to the clarifier). The
underflow concentration from the secondary clarifier was 4 percent in
the pure oxygen system versus 1 percent for the air system. The sludge
production was equivalent for both systems. The thickening and dewater-
ing characteristics were much better for the pure oxygen than for air.
It was also concluded that the oxygen system was shock resistant and
recovered from shutdown much better than air. With air, a 1 week period
was required to recover from a 10-day shutdown, where the pure oxygen
system responded immediately with satisfactory results. The fuel con-
tent of the sludges was about the same at 9,400 BTU/lb.
It was concluded that the pure oxygen system should be operated
at higher F/M (therefore, less land space) and perform much better from
a BOD removal-sludge handling standpoint than the air system. The oxygen
requirements are slightly higher for the pure oxygen system, but the
sludge production was approximately the same. The pure oxygen system
provided better stability.
A.4 Paper No. 48
This paper addresses the analytical capabilities of measurement
of oil and grease in petrochemical wastewaters and presents the perfor-
mance of the various technologies for removing these materials. The
paper discussed sampling techniques, including collection techniques to
deal with stratification in the sewer and handling techniques to avoid
contamination by oil from hands in low-level samples.
Tests were conducted using 31 laboratories and statistical
correlations of these results were provided. The Freon extraction tech-
nique was specified and data from three labs were eliminated because the
statistically acceptable range was exceeded. Data from the remaining 28
labs were reported and results correlated to evaluate the analytical
reliability and variability among the samples. The results from the Freon
extraction-infrared method were considered less variable than those results
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using Freon extraction-gravimetric techniques. The absolute value from
the infrared technique may be in error because of the standard used.
It was concluded that significant variations in yield exist between
detection methods which result in a high degree of variability in the
analysis. The analytical variance as a function of concentration indi-
cates more significance than concentrations less than 10 mg/£.
The review of treatment technology for oil and grease removal
from petroleum wastewaters indicated that biological treatment, when
well designed and well operated with adequate pretreatment, can produce
average effluent oil and grease levels from 3 to 12 mg/£ on a 50 percent
probability basis with high concentrations in the range of 20 to 60 gm/£
(98 percent probability). The addition of post-filtration to biological
systems lowered the average value in the range of 6 to 7 mg/£ on a 50
percent basis and 20 to 30 mg/£ on a 98 percent probability. The observed
oil and grease removal from two activated carbon adsorption facilities
treating refinery wastewater was comparable only to biological treatment
technology. Concentrations in the range of 1.7 to 10 mg/l of oil and
grease have been demonstrated in pilot-scale tests using activated carbon
but in the United States there are no operating facilities on petroleum
refining industrial wastewaters which confirm these results.
B. Prepared Discussions
B.I A formal discusser cited the lack of an accurate design
basis since literature values were used for the catalytic oxidation and
the bio-filtration system. He said the comparison was good with the
results probably applicable only to developing countries since much land
and continuous sunlight was needed.
B.2 The discussion was brief and the discusser stated that
1) yeast production must be feasible with most wastewaters to date;
2) the separation of the yeast is difficult and the effluent still
required additional treatment; 3) it was more feasible to produce pro-
tein on a commercial agricultural basis; and 4) additional modeling
should be done with the data provided by the authors.
B.3 The discusser indicated that more in-plant work should
be explored in pulp and paper mills; for example, the Rapson system which
employs a titanium-clad reactor for recycle of streams to control the
sodium chloride level. The discusser indicated that oxygen does look
good, but that some data in the past have been misleading and careful
consideration should be given to all cost data before the final decision
is made.
B.4 The discusser agreed that analytical standards are prac-
tically impossible to establish presently because of the analytical
variability in the method used. It was also agreed that biological
treatment provides a level of treatment which is just as acceptable as
that from the physical-chemical treatment with petroleum wastewaters.
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C. Floor Discussion
C.I Questions were raised on the design and operation of a bio-filter
and the fact that the design of the bio-filter and catalytic oxidation
were taken from literature.
C.2 There were no questions from the floor.
C.3 The floor discussion clarified the reference to UNOX as the
oxygen system. UNOX was not the only oxygen system examined; however,
UNOX personnel had worked closely with the investigators and the authors
referred to UNOX and pure oxygen interchangeably. It was pointed out
that the fiber content was composed of short fibers in the mill.
C.4 Questions were asked from the floor concerning the use of Freon
instead of hexane as the solvent in the oil and grease analysis. It was
stated that Freon had been selected by EPA because it offers a safer
chemical to use in the laboratory. Other questions arose concerning the
use of analytical techniques to distinguish between oils of vegetable and
animal origin as compared to those oils of mineral origin. The author
stated that he had had no experience with this. I mentioned that I had
had some experience and that I was under the impression that there was not
a readily available technique to distinguish between oils and greases of
vegetable and animal origin and those of mineral origin and that EPA had
been examining this difference. However, the basis of distinguishing
between those oils and greases of different origins was primarily based
on the production methods of a specific industry. For example, those
industries which make edible oils should only have oils and greases of
vegetable and animal origin in their wastewaters unless they had pump
leaks which might leak mineral oils, used for lubricants, into the sewer.
This could generally be checked on a case-by-case basis.
D. Other Observations and Comments
D.I The catalytic oxidation system and bio-filtration system would
probably only be applicable in the United States as pretreatment ahead
of municipal discharge or pretreatment of some other aerobic biological
process. In this case, the bio-filter would serve as a roughing device
and the catalytic oxidation system would be used only for highly concen-
trated streams. The cost data seemed accurate, but I do not feel that
they included all of the personnel costs. The bio-filter design was
probably not optimized and was selected from literature where one or two
pilot cases were examined. The most accurate data available were for
the anaerobic lagoon; however, it/was not modeled and sufficient data
were not presented in order to determine its performance on a seasonal
basis. No nitrogen data were presented other than influent, which is
unfortunate.
D.2 There was quite a bit of interest in single-cell protein pro-
duction. However, most people agreed that at the present it was not
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feasible on a commercial basis; the effluent organic concentration
was too high and still required additional treatment, and protein can
be produced cheaper from an agricultural basis. A considerable amount
of the data presented could be used to generate models to predict anaero-
bic treatment of high-strength organic wastewaters.
D.3 Further discussion showed agreement that the oxygen system
appears good for the pulp and paper industry and that a good job had
been done on correlating the data. Additional correlation may have
produced more conclusive results.
D.4 Serious doubts were raised by the paper concerning the measure-
ment and analytical techniques of oils and greases. This problem is even
more serious with industries who use vegetable and animal oils. There
is a great need for more accepted methods, which may have to be developed
by EPA, to distinguish between oils and greases of vegetables and animal,
and mineral origin. Also, there needs to be either a very reliable,
accurate technique for measurement of oil and greases, or the permits
should incorporate the statistical variability which has been proven for
this test.
IV. CRITIQUE OF SESSION
Of the four papers presented in this section, the following com-
ments are offered. Papers No. 39 and 42 were not research oriented studies
and only reported abbreviated results. No. 39 compared three systems,
but only presented data on one system. Additional data should have been
provided on the system presented. This paper has very limited application
to the United States.
Paper No. 42 was not a research study and does not apply to the
United States but to developing countries. However, some good data were
presented regarding anaerobic ponds. These data could be analyzed to
generate or confirm design models for anaerobic treatment of high strength
wastes.
Papers No. 45 and 48 were very good and highly attended by top
caliber individuals in the profession. Although these papers were not
research in the true sense, they did confirm other data which had been
previously published and presented. Significant correlations of these
data established several key points which I thought were important to
situations in the United States.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Since no papers were truly research oriented, it was difficult
to delineate definite research needs. The data of Paper No. 45 could pos-
sibly be correlated better to give a more acceptable comparison of air
and pure oxygen. This paper, along with other results I have seen, gives
a strong case for the use of pure oxygen in the pulp and paper industry.
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Paper No. 48 (oil and grease) definitely stressed the need for
improving analytical procedures. Also, emphasis was placed on the fact
that physical-chemical treatment is not as definitive as EPA has led many
to believe. It should be noted that a well operated biological system
may satisfy the requirements for BATEA with appropriate pretreatment such
as filtration.
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I. SESSION
A.
B.
Theme of Session: Monitoring of Waste Discharges
Papers Presented: 51
54.
57.
Pollution Control Regulations and Monitor-
ing Technology: A Review of Research and
Development from the Pulp and Paper Industry.
D. V. Ellis (Canada)
Biomonitoring with Fish: An Aid to Industrial
Effluent and Surface Water Quality Control.
W. S. G. Morgan (South Africa)
The Use of Ozone Induced Chemiluminescence
in Water Quality Monitoring.
V. A. Garten, R. B. Head, R. McNeill,
J. M. Overbeek (Australia)
II. REVIEWER
A. Name: Howard Edde
B. Position and Affiliation:
President, Howard Edde, Inc.
1309 - 114th Avenue Southeast
Bellefield Office Park
Bellevue, Washington
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 51
The paper by Mr. Derek V. Ellis was an excellent contribution in
describing the pollution control procedures applicable to the pulp and
paper industry in British Columbia, Canada.
The data base in the paper came from monitoring results of 11
coastal pulp and paper mills and one large sawmill in British Columbia.
Experimental procedures were presented and discussed for monitoring within
the "zone of influence" of these outfalls. This zone included the three-
dimensional space in which the discharge can be shown as present or as
having an effect or the ecosystem, ft series of monitoring tests, conducted
within the zone, were presented and critically analyzed by the author.
These data were used in making an appraisal of the marine water receiving
area. Depending upon the magnitude of the pollutant's impact, only one
routine procedure or all of the procedures may be required to appraise
the effect of the pollutants on the environment.
The monitoring procedures are useful in determining industrial
compliance when the discharge regulations are so worded that compliance
or non-compliance can be demonstrated by single samples from test and
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control stations for one or more parameters analyzable by the discharger's
process control laboratory.
A.2 Paper No. 54
This paper presented the details of a rapid electronic biological
automom'toring system which utilized the fact that fish opercular rhythms
increase under toxic conditions. Field application of the system also has
the ability of controlling toxic industrial discharges. The details in
the paper dealt almost entirely with the how, why, and where of using this
device in actual continuous monitoring situations.
The author concluded that the response limit of fish sensors
lies between 5 and 10 percent of the 48-hour lethal limit. He believed
this respiratory response of fish is a reliable parameter for use in
biological automom'toring systems. The monitor enables an industry to
take immediate remedial action should the toxicity of its waste increase.
A.3 Paper No. 57
The paper was presented by Mr. R. McNeill of CSIRO-Melbourne,
Australia. The paper dealt with a device for water quality monitoring
which utilized the almost instantaneous chemiluminescent reaction of
certain readily oxidizable, organic (and inorganic) materials with ozone.
This phenomenon is due to the fact that ozone can react as either a
1,3-dipole, an electrophile, or a mucleophile. This makes it possible to
distinguish between different chemical groups present in a mixed substrate.
Generally, the recorded photon count is proportional with the
concentration of certain substances in the water. However, some anomalies
exist. For example, a pure solution of sucrose gives inconclusive results.
Also, the measure is pH and temperature sensitive.
B. Prepared Discussions
B.I Mr. Lars Hall of Sweden noted that the paper indicated other
ways of controlling pollution exist and that the British Columbia Pollu-
tion Control Act indicates that pollution should not interfere with the
water's use. However, the paper failed to recognize that in-plant control
is the real place where emphasis should begin in the protection of receiv-
ing waters. This is the better approach to the solution of the problem.
Thus, it was emphasized in the discussion that the implementa-
tion of the best technical solutions that were economically achievable
do not relate solely to the state of the receiving waters as might be
implied in Mr. Ellis' paper. Instead, the solutions should consider how
the production process itself could be improved by in-plant control,
thereby minimizing the development of a potential receiving water problem.
Thus, it may not be necessary to use the maximum resources of the receiving
water for waste assimilation. Long term effects by successive discharges
can be prevented by the in-plant approach to the problem's solution. Only
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after the worst in-plant problems have been corrected by maximum in-plant
controls is it proper to use receiving water quality as the determinant
in establishing a base for further pollution control requirements.
The principles proposed by Dr. Ellis are in agreement with modern
Swedish thinking with regard to the receiving water question. This should
be limited to a few key water quality parameters within a geographically
restricted area for reasons related to the cost of monitoring these waters.
The studies within the zone of influence should be conducted over a long
period of time with each study conducted at approximately three-year
intervals to establish long term effects. Sea bed effects are most impor-
tant as a part of this type of study.
B.2 Dr. John Cairns of the United States noted that Morgan's research
on biomonitoring is among the best for the field. Dr. Cairns suggested
this system may be more useful for the less skilled operators if the thresh-
old response were replaced by a probability of harm estimate. In this
manner the readout would be like a weather report, i.e., 20 percent chance
of rain (toxic conditions) being experienced today. This may prevent pos-
sible false alarm signals from causing a needlessly expensive plant shut-
down.
Dr. Cairns emphasized that some back-up is needed in that an
in-plant biological monitoring system should never be the sole means of
evaluating the effects of a waste discharge upon a complex aquatic eco-
system. We cannot afford to ignore the limitations of even the best
methodology. This limitation might be partially offset by using species
of several trophic levels in the system.
B.3 Mr. Cyril Cornelia of France noted that for the moment this
method is not useful for routine laboratory analysis carried out by medium
level staff. The paper does not explain what method is applied to deter-
mine the rate of spontaneous decomposition of ozone and the correction to
be applied for exact determination of actual ozone consumption. Also, no
data are given regarding the cost of this device.
It was acknowledged in the author's paper that chemiluminescence
can and cannot be induced by ozonation. In some cases (low temperature
and low concentration, for example) many chemical bodies escape from ozone
attack. For these and other reasons, it is not possible to place a general
and absolute significance on the induced chemiluminescence test.
The test may have some value when bodies are polluted with
specific materials that do have a good chemiluminescence response to ozone.
This might include petrochemical effluents, pulp mill effluents and natural
waters with a high content of humic acids. At this time this instrument
is suited for research laboratory work and is not yet adapted for routine
laboratory or field work.
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C. Floor Discussions
C.I The following significant observations and comments were made
during the floor discussion. Dr. Michael Kingsfort (NZ) commented on the
operation of pulp mills in his country. He mentioned a problem of ineffi-
cient operation of chlorine cells. This resulted in a high level of
mercury in fish taken from the lake. Another problem is foam released
below a hydrostation tailrace. It was implied that these are problems
best prevented by in-plant control and that they should never get to the
point where a receiving water investigation is required to detect the
problem.
Peter Higgins (Canada) emphasized that Canadian regulations under
the Federal Fisheries Act also place emphasis on in-plant controls and
that this may not have been sufficiently emphasized in the formal paper.
Every mill in Canada is basically required to meet the same minimum level
of controls.
Mr. Vordman (UK) spoke to the problems of zinc in pulp effluents.
The speaker indicated this is used in groundwood bleaching and present
technology has resulted in boron compounds replacing zinc as a bleaching
agent. Again, the comments from the floor emphasized the significance of
in-plant controls as opposed to subsequent monitoring of recipient waters.
C.2 The following significant observations and comments were made
during the floor discussions. Mr. Morgan emphasized that in South Africa
operators do not like to make decisions and hence the "probability of
toxicity concept" is not applicable since the evaluation is always made
by the responsible person in charge.
The tendency of fish biomonitoring research is toward breathing
rate monitoring and away from the cough rate monitoring system that has
been proposed earlier by several researchers. This is because some fish
cough and some fish do not cough. Thus, coughing is not a reliable method
of monitoring. The fish in Dr. Morgan's system were used for no more than
three months (to prevent conditioned responses). Once a fish responded,
that fish was never used again since the future response of the fish was
then not predictable.
If the system is used in a field application, the surrounding
food must be filtered out of the water. Feeding the fish interferes with
the fish response to the biomonitoring system. Therefore the researcher
must be careful to not monitor the fish during the feeding period.
C.3 The claim that a two or three percent instrument accuracy existed
was questioned from the floor and the author explained this was based on
analysis laboratory samples of pure compounds. The device is not claimed
to be a substitute for TOC or other basic analytical parameters. The effect
of possible interfering compounds such as chlorides has not been investigated.
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D. Other Observations and Comments
In Dr. Ellis' response, he emphasized that the monitoring work
he describes in the paper points to the need for impact assessments being
made on new plants before they are built. Thus, this may result in the
new plant's implementing improved production technology as a preventative
measure and thereby preserve the receiving water area. Dr. Ellis believed
that in-plant technology and recipient monitoring have considerable inter-
play in the realization of industrial pollution control.
The paper on biomonitoring was well received by the session
attendees. It pointed out significant advances that are being made in
understanding and applying the knowledge of biomonitoring of fish. An
additional useful aspect of these developments in biomonitoring is that
this information can be a useful indicator tool to signal industrial plant
operators and managers of deficiencies which may be unknowingly occurring
in the production process, thereby needlessly releasing toxic elements.
Biomonitoring of fish can thus become a tool to improve the efficiency of
production process operations within the industrial plant.
The author (Paper No. 57) stated in his presentation that he
would be receptive to suggestions from the conference attendees on means
to put this device to a practical use. This appears to be the situation
where an idea has been developed and is now in search of a purpose for
which it can be usefully applied.
IV CRITIQUE OF SESSION
I believe the floor discussion of Paper No. 51 indicated to the
more aware conference attendees that today throughout the world the prob-
lems of industrial pollution control are increasingly shifting from
(a) the traditional environmental engineering approach of studying the
effects of a problem and then looking for a traditional solution to (b)
attacking the problem of pollution at its point of origin within the
production process and in this manner reducing the pollutant discharges
to the maximum levels with available technology. This approach thereafter
requires further external treatment based on an evaluation of the recipi-
ents assimilative resources.
In the case of new factories, the pool of knowledge related to
effects of pollutant discharges on the recipients is a useful tool in
evaluating where the new factory should be located. Increasingly today
the decision process on plant location is also supplemented by social-
economic evaluations which must go hand in hand with environmental evalu-
ations.
The paper by Mr. Ellis was well prepared. Its greatest useful-
ness at this conference may have been to motivate the attendees to recog-
nize that a monitoring program can bring about change which may prevent
pollutants from ever being originally released to the recipient from the
industrial production process.
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Paper No. 54 was excellently prepared and the discusser, Dr.
Cairns, was knowledgeable of the subject material. The discussion was
therefore excellent and concise. The paper pointed out many of the most
recent trends, developments, and limitations of biomonitoring with fish.
The paper and review elicited thoughtful response from the audience.
Paper No. 57 described a research instrument that is still in
the developmental stage. Before this instrument can find widespread use,
it will be necessary to further define its practical applications that
were broadly proposed in the paper. The attendees generally recognized
the limitations which exist with the present state of development of this
concept and instrument.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The paper by Ellis and its discussion pointed to a need that
research on industrial pollution problems in the United States should be
directed to understanding how and why pollutants originate in the produc-
tion process. This knowledge is essential in order for implementation of
the most cost effective solutions to the problem.
Paper No. 54 was an excellent paper which presented an example
of water pollution research effectively applied as a practical tool.
Application of this technology will most likely result in many industrial
dischargers becoming more cognizant of toxic material in their wastewater
discharges. This in turn may lead to a further clean up of toxic dis-
charges from the production process itself.
This paper (No. 57) described instrumentation which is presently
in an early stage of development. Its immediate value in the United States
may be limited. The need and usefulness of the concept should be further
evaluated before a parallel interest of development is justified in the
United States.
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SESSION
A. Theme of Session: Water Resources Quality Management
B. Papers Presented:
Workshop - Water Resources Quality Mangement
Convener: W. K. Lewis
Speakers: P. M. Higgins (Canada), L. B. Wood (UK),
H. Schmidt (Fed. Rep. Germany), M. R.
Henzen (South America)
II. REVIEWER
A. Name: Robert A. Canham
B. Position and Affiliation:
Executive Secretary, Water Pollution
Control Federation
2626 Pennsylvania Avenue, N.W.
Washington, D.C.
III. REVIEW OF SESSION
A. Formal Papers
A.I The speaker from Canada, Higgins, separated his remarks into the
following subjects:
1. Canada's soft water lake systems, their low buffering capacity
and resultant sensitivity to S02 and nutrient loading.
2. Lake eutrophication and its acceleration by excess nutrients.
3. Man made lakes as they are affected by previous control decisions.
4. Possible conflict and principles in the relationship between
water resources management authorities and those required to
comply with water quality management decisions.
The speaker discussed in broad terms the circumstances in Canada
whereby there are many areas where the lakes receive acid from sulfides
from the natural mineral sources. The resultant low pH of the water does
not encourage vegetative growth and is not an attractive environment for
fish.
There was no discussion of suggested solutions nor a program
that is dealing with the problem. As a result management of these water
resources was not discussed. Problems of eutrophication, particularly in
the Great Lakes, were discussed. Management of the problem was not dis-
cussed except to indicate that some sort of a concerted effort is needed.
The well documented circumstances of DO and waste assimilative
capacity in impoundments were discussed but no detailed discussion of
management techniques was included. Beyond commenting on the fact that
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there are philosophical conflicts between those who view impoundments for
different uses and the comment that in Canada regulations for industrial
discharges are developed cooperatively with industry, the author did not
discuss management alternatives arid merely wondered whether the cooperative
approach will work.
A.2 The speaker from the United Kingdom, Wood, discussed in general
terms a textbook approach to management of water resources quality and
then discussed some of the major problems facing the newly organized regional
water authorities in U.K. His emphasis was on the financial crisis that
has confronted Britain in recent years and how it is affecting the activi-
ties of the regional water authorities.
The author proposed solutions to the problem and it is unlikely
that many would disagree with the reasoning. However, a careful look at
the proposed solutions suggests that in each enumerated solution there
would be enormous cost involved. As a result it appears that the solutions
offered will not be attained because of the financial problems and that,
therefore, there will be business as usual.
A.3 The speaker from West Germany, Schmidt, chose ground water as
his subject. Since ground water is and will continue to be a major source
of water in Germany there is a high priority set on its management. The
basic reason for this is that about 2/3 of the water sources now is from
ground water and the demand is predicted to increase 50 percent by the
year 2000.
As the other speakers did, this author discussed a series of
reasons why additional work is needed to protect the ground water but he
went somewhat further to discuss some of the ways that the government and
the technical community have tried to attack the problem. Mostly these
have been regulations and guidelines made possible by a national law on
the water budget. The regulations provide some uniformity and limits on
activities that jeopardize the quantity and quality of ground water. How-
ever, there is scant reference to any results of the relative degree of
effectiveness of the law and its regulations. The author did refer to a
five-year plan (1977-81) of the European Communities that places high
priorities on the protection of ground water but without sufficient detail
to understand the plan.
A.4 The fourth speaker (Henzen), who was from South Africa, discussed
the problems of acid mine drainage. Since South Africa is a major producer
of metals for the world market it is natural to assume that acid mine drain-
age is a primary problem. Since South Africa is a water-short country this
is even more important.
He referred to the Water Act of 1956 which sets national water
quality standards for water used by industry but pointed out that the
standards do not apply to underground water pumped from mines or runoff
from mine dumps. Regulations were developed in 1976 for these waters.
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The author discussed in considerable detail the various problems
of acid mine drainage including data and he discussed some solutions. How-
ever, the status of the work to solve the problems is mostly in the research
stage and there is little evidence of full-scale results of applying various
theories. In fact, most of the solutions discussed were theoretical.
B. Prepared Discussions
There were no prepared discussions in this workshop. All dis-
cussion was handled by the Chairman through the selection of questions or
statements made on cards submitted by the audience during the session.
C. Floor Discussions
There was an active discussion from the floor; some of the more
pertinent dialog is mentioned briefly below.
It was pointed out that none of the speakers included socio-
economic matters as a part of the presentation and that these are important
in a management program.
It was brought out that in Germany a new discharge law sets a
schedule of payments for pollution in different degrees and that there are
controls imposed on quantities of discharge as well as quality.
The Canadian speaker emphasized the difficulties with imposing
requirements on old, existing industries vs. the lesser problems of the
same requirements with new plants. Canada requires a comprehensive assess-
ment of all new chemicals.
Implementation problems in the new regional water authorities
in the U.K. were discussed and it was apparent that some of the require-
ments or manifestations are similar to current experience in the U.S.
The requirement for public disclosure of all data has led the Thames
Authority to a different stream classification concept which identifies
priorities. Also it was stated that in the U.K. the policy is that the
polluter pays (and therefore is allowed to discharge some degree of pollu-
tion) but that toxics must be removed.
In Germany it was revealed that the new requirements for pro-
tecting ground water include such details as diversion of surface water
during construction; that there is some effect on vegetation from ground
water withdrawal; that problems of oil transport by pipeline, truck,
rail, etc. have not been solved; and that there is no solution in sight
for ground water that already is polluted.
Relative to acid mine drainage, the speaker from South Africa
responded to questions in several areas by saying that the mine owner is
responsible for the water on his site only, that the government monitors
surface water that flows through mine areas, that there is no federal
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subsidy for construction of corrective systems for gold or coal mines,
and that there are requirements for treatment of process water in con-
struction works when the water is supplied from the outside.
The Chairman summarized the session by pointing out that effec-
tive management can only be carried out with proper organizational frame-
work and with cooperation, that both short- and long-term objectives must
be incorporated, that adequate financing is necessary, that practical
legislation is needed, and that in the development and implementation
there is a need for more research.
IV. CRITIQUE OF SESSION
The philosophy behind the planning of this session may have
been reasonable but the results left the listener far short of high value.
There was no cohesion in the subject matter and none developed in the
presentations and very little in the discussion.
The idea of haying speakers from four countries was excellent
but apparently the planning specified that the four subjects also were to
be different. It would have been much more useful to ask four speakers
from different countries to discuss the management aspects of any one of
the subjects, i.e., lakes and impoundment, rivers and estuaries, acid mine
drainage, or ground water. There was more information exchanged in the
discussion period than in the presentation, even though the discussion
time was short.
A major criticism was that the subject of the session, Water
Resources Quality Mangement, really was not covered if the listener
expected to learn something about effectiveness of management. The
speakers dicusssed at length the problems that need to be solved through
management techniques but left the listener wondering whether any progress
has been made or whether there has been any evaluation of the effective-
ness of the management structures. In some instances there was no dis-
cussion of the strategy being used and in others the discussion was only
about the theoretical management needs.
The speakers in general provided reasonable background on the
problems and this is necessary, but it would have been much more useful
if more attention had been given to the methods and measures of effective-
ness of the work underway to provide solutions to the problems.
One positive aspect of a session like this is that it identifies
individuals throughout the world who can be called on through continuing
communications to discuss more details in the areas of their expertise.
It was obvious that there was strong interest in the session as
measured by the number who attended, the high percentage who stayed through-
out, and the number of questions. However, it is felt that the value of
the session was far less than it could have been if a different set of
specifications had been given to the speakers.
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V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
This session, not being on research, has a different set of
values to American researchers but nevertheless has some.
The speaker from South Africa discussed research projects under-
way that are aimed at dealing with the problems of his subject, acid mine
drainage. However, he is a research individual and the contents of his
paper are to be expected. The other speakers are not research people and
their papers reflected this fact.
The Chairman correctly included .a comment that more research is
needed to deal with the problems of water quality management but that was
not the thrust of the session. As a result of these factors this workshop
had limited value to American researchers pan. &&. If the results of
research were matched with earlier objectives and programs in water quality
management, the session would have been more useful to the U.S. research
community.
It is questionable whether the program for this conference
should include workshops with subjects like this since they do not fit
the original objectives of the sponsoring organizations.
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I. SESSION
A.
B.
Theme of Session: Toxicity of Industrial Wastes
Papers Presented:
58. Development of a Rapid Fish Toxicity Test
Utilizing a Freeze Concentration Technique
for Routine Petroleum Refinery Wastewater
Monitoring.
E. C. Birchard (Canada)
61. Compounds Toxic to Fish in Pulp Mill
Waste Streams.
J. M. Leach, A. N. Thakore (Canada)
II. REVIEWER
A. Name: Richard D. Pomeroy
B. Position and Affiliation: Consultant for Special Projects
Jacobs Engineering Co.
Pasadena, CA
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 58
Three of the papers, Nos. 58, 61 and 70, dealt with various
aspects of toxicity tests by bioassays, reflecting an awareness that more
needs to be known about this widely-used method for effluent monitoring.
The particular paper examined in this review is No. 58, authored by E. C.
Birchard, but reference will be made also to No. 61 because of its perti-
nence in an overall view of the subject.
The object of the research reported in Paper No. 58 was to find
a way to obtain indications of the toxicity of wastewater from oil refiner-
ies and petrochemical plants without waiting the full time specified for
the standard test. In effect, it is desired to obtain in a few hours a
test equivalent to a 24-hr TL-50 result and, in a similarly shortened
time, to obtain an estimate of the probable 96-hr result. The method
selected for investigation in this research is concentration of the toxi-
cants into a smaller volume before accelerating the response to any
toxicants that may be present.
A procedure for concentrating the toxicants in a wastewater
should, insofar as possible, remove water from the solution, leaving the
dissolved toxicants unaltered except as to concentration. There is no
way to accomplish this concentrating effect that will assure that the
ideal objective can be attained. Concentration by freezing will trap some
portion of the toxicants in the ice. Removing part of the water by
evaporating it is likely to vaporize some of the organic components as
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well as the water. A reverse osmosis membrane has the disadvantage that
most solutes, especially non-polar ones, will pass through it to a sig-
nificant extent. Furthermore, any concentrating technique may encounter
boundaries imposed by solubility relationships.
Mr. Birchard concluded that freezing out part of the water held
the best hope for getting useful results.
A.2 Paper No. 61
A question naturally arises as to whether chemical tests might
not be an alternate way to get a prompt indication of toxicity. This
question came to the fore in Paper No. 61. A remarkable piece of research
was there described in which a high degree of analytical skill was shown
in determining toxic components in 124 wastewater samples from wood pulping
operations. Twenty-six complex organic compounds, including resin acids,
fatty acids, terpene alcohols, juvenile insect hormones, and chlorinated
organics, were identified and quantified. Furthermore, toxicites of the
wastewaters were quite closely predicted from the analyses and the known
toxicities of the components. Despite the success of that research, it
does not presently appear that the chemical method could replace the
bioassay for the pulp industry, because a complete chemical analysis would
take far more time and effort than the bioassay. It is possible that
proximate analyses for certain classes of compounds, or the determination
of a few of the most important of the toxicants, would give results that
provide adequate correlation with overall toxicity. Insofar as analytical
results can be used this way, they afford best means for setting sub-lethal
standards of toxicity.
B, C & D. Discussions
The prepared discussion was presented by J. Cairns (US). The
review of all of the discussions, including those from the floor, and also
information from other papers and arising from this writer's background,
are presented in an arrangement based upon subject matter rather than upon
participants.
When wastewater from one Canadian refinery was concentrated by
freezing to one-fifth of the original volume, the concentrate contained
from 70 to 79 percent of the ammonium, sodium, chloride, total organic
carbon, and total solids. Thus, the concentration ratios for these
materials were relatively uniform at between 3.5 and 4. Zinc recovery,
however, was only about 50 percent. When another refinery wastewater
was spiked with solutions of Cu, monovalent Hg, Ni, Pb, In and trivalent
Cr, the results were quite erratic. This is not necessarily a matter of
concern with refinery wastewaters since these metals are rarely present
in significant amounts in these wastes, except for the occasional presence
of hexavalent chromium from cooling towers.
Using wastewaters from four refineries in Canada, comparisons
were made of results by two laboratories for the standard 24-hr static
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tests and also results from the 96-hr flow-through tests, survival times
with freeze-concentrated samples, and survival times with samples that
had been freeze-concentrated and then reconstituted. A sample from a
fifth refinery was tested oni by the 96-hr test and by determining
survival times after freeze-concentrating. Fish survival times in the
four unaltered samples ranged from about 15 min to 800 min.
Fish survived an average of 60 percent longer in the reconsti-
tuted samples, showing that some of the toxicity was lost in the process
of freezing and then reconstituting the sample from the ice and the con-
centrate.
Regression equations were developed for correlating by pairs
the results by different methods or laboratories; five such equations
were developed. One discusser criticized the method of calculating the
equations. It seems that a more serious criticism is the paucity of the
data. Only four samples were tested by all five methods and a sample
from a fifth refinery was tested by two methods. Four or five pairs of
x-y values, particularly when the results are quite scattered, as they
were in these tests, do not afford a very good basis for conclusions.
The correlation equations are rather trivial, anyway.
The author estimates that a bioassay after employing the freeze-
concentration technique will give in five hours about the same result as
will be found in the standard 24-hr test, and in 13 hours the result will
be about the same as in the standard 96-hr test.
In answer to a question about the nature of the toxicants in
the wastewaters, Mr. Birchard said that the principal ones known to be
present are ammonium, HCN, and phenols.
More work on identification of toxicants in the refinery waste-
waters should be undertaken. The task should be considerably easier than
with the wood pulping wastes.
It will probably be agreed by all workers in this field that
toxicity monitoring by bioassays will continue to be necessary as a
catch-all method for the unknowns. It is probable, however, that greater
attention to analytical tests might often accomplish the objectives sought
in the research reported in Paper No. 58.
In answer to a question, Mr. Birchard agreed that the applica-
bility of the freeze-concentration technique could not be assumed for any
type of waste other than the wastes for which it was tested. He does not
propose its general use, but showed that it can be serviceable to providing
the refinery management with an early warning of excessive toxicity in the
discharged wastes. It is inferred that it may prove similarly useful for
other industries as well.
It was pointed out by one discusser that from the time of
sampling until the time of obtaining a result from the freeze-concentrated
sample would be about eight hours because the time for the preparative
manipulations must be included.
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The importance of an early warning technique is related to the
variability of the effluent, One paper of the conference (No. 31) dealt
mathematically with the subject of variability. Whatever the nature of
these relationships, it is obvious that if the wastewater passes through
completely or partially mixed basins, effluent variability will diminish
as the retention time increases. If a refinery uses large ponds for
treatment, as some do, with detention times of several days, the rate of
change of effluent quality is slow enough so that accelerated bioassay
tests would not be very important. Long retention times should be
encouraged as a means to minimize the danger of toxic discharges.
IV. CRITIQUE OF SESSION
The papers were critiqued in the Discussion Section.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The subject of detecting unacceptable discharges is tied in with
the general question of enforcement of standards. It is not particularly
effective for a pollution control agency to set an effluent toxicity limi-
tation based upon a concentration that is expected 1 or 2 percent of the
time, or to tell an industry that it is allowed a certain number of
violations per year. This is a contradiction in terms. An industry does
not like to be recorded as having been in violation if it has in fact
done only what is allowed.
It is appropriate that there be effluent limitations that the
industry should never exceed. More important, the industry should show
that it has provided the means to prevent such discharges. It has long
been required that a refinery provide dikes around tank farms as security
against massive oil spills. Diked areas or other kinds of basins should
be provided for the diversion of unacceptable effluents so that the refinery
(or other industry) can continue to operate during a period when the treat-
ment plant effluent is unacceptable for discharge. This is not a part of
the subject matter of Paper 58, but it shows a use to which an accelerated
bioassay test might be put.
It is not expected that the concentration technique for acceler-
ated bioassays will be widely applicable, but it is useful to know that
the technique has been examined and that it may prove useful at least in
the petroleum refining industry.
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I. SESSION
A. Theme of Session: Stream Oxygen Balance and Bioassays
B. Papers Presented: 64.
67.
70.
Nitrification in Free-Flowing Streams.
F. F. Lopez-Bernal, P. A. Krenkel,
R. J. Ruane (USA)
Consideration of the Efficiency of
Attached Organisms in the Simulation of
Self-Purification and Oxygenation Capacity
of Flowing Waters.
P. Wolf (Germany)
Comparison of Semi-Continuous and
Continuous Flow Bioassays.
J. H. Reynolds, E. J. Middlebrooks,
D. Porcella, W. J. Grenney (USA)
II. REVIEWER
A. Name: N. Bruce Hanes
B. Position and Affiliation:
Professor and Chairman, Department
of Civil Engineering
Tufts University
Medford, Massachusetts
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 64
The paper entitled "Nitrification in Free-Flowing Streams"
represented a practical approach for predicting dissolved oxygen levels
in rivers and streams where nitrification is a significant factor. It
should be noted that the consideration of nitrification in deriving dis-
solved oxygen levels in our waterways has increased in importance as the
United States water pollution control program has made progress in
reducing the carbonaceous waste material in our streams. The authors
cited recent examples where nitrogenous oxygen demand was actually
greater than that of carbonaceous material. This reviewer has also
personally experienced similar conditions in recent stream survey work.
Also of interest was the evidence presented that attached organisms play
an important role in the nitrification process.
The authors stressed that the nitrification model developed in
their presentation was "descriptive" rather than "predictive," thus
requiring field data collected under conditions similar to those under
which the model is applied. The nitrification process was represented
in the model by zero order and/or first order reaction equations.
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Procedures for the development of both equations were presented. In this
study Knr represented the stream nitrogenous BOD distribution coefficient
that included removal of nitrogenous oxygen demand by oxidation plus the
effects of equilibration, cell synthesis and other factors while Kn rep-
resented the removal of nitrogenous oxygen demand by oxidation only. The
authors gave the following typical values for Southern rivers:
K 1 K 2
*n &n
Knr (N03) (NH4)
4.1-1.33 1.68-0.50 0.37-0.65
1 based on increase in nitrate nitrogen
2 based on decrease in ammonium nitrogen
A.2 Paper No. 67
This paper entitled "Consideration of the Efficiency of Attached
Organisms in the Simulation of Self-Purification and Oxygenation Capacity
of Flowing Waters" represented a different approach for the prediction of
dissolved oxygen levels in both natural and man-made waterways. The author
developed a model that is dependent on oxygen removal by suspended and
attached organisms. He noted that in the case of shallow turbulent streams,
the effect of oxygen removal by attached organisms cannot be ignored. The
rate of oxygen removal by the attached organisms is estimated from data
obtained from rotating bio-disks treating domestic sewage as well as the
depth and roughness of the stream under study. The rate of oxygen removal
by suspended organisms is estimated on the basis of the kinetics of domes-
tic sewage which was found to differ for mechanically purified and biologi-
cally purified wastewaters. The author has applied the model to 10 differ-
ent waterways which included a 1000 m model channel, small mountain streams,
larger streams and finally the lower reaches of the Rhine River all with
good results. The unique aspect of this model is its requirement for a
minimum of actual data from a particular stream.
A.3 Paper No. 70
The paper entitled "Comparison of Semi-Continuous and Continuous
Flow Bioassays" presented the theory relating semi-continuous flow cultures
to continuous flow cultures as well as evaluating results obtained from a
toxicity bioassay study employing both techniques. The semi-continuous
flow culture technique is an approximation of the standard continuous flow
system and may prove useful as a screening technique of toxic substances.
Thus a comparison of the two systems is the first step that must be taken
in determining the value of the development of a standard semi-continuous
flow culture procedure. An evaluation of the basic theory of the two
systems suggests that one could expect comparable results. A comparison
of the actual data indicated that competitive inhibition constants
obtained from semi-continuous flow cultures indicated less phenol toxicity
to the algae Se£enoA£*um cja.piLc.orwutwn than inhibitor constants obtained
from continuous flow cultures. The authors suggest that this difference
may be a function of cell growth rate in comparison to the time interval
between withdrawals.
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B. Prepared Discussions
B.I The prepared discussion for Paper No. 64 was presented by J.
Garland (United Kingdom). He conceded that the nitrification process
appeared to be adequately described by zero order and/or first order
reaction equations but stressed that in theory the process was actually
an autocatalytic growth reaction. Mr. Garland expressed disappointment
that the authors had not attacked the nitrogen balance directly but
acknowledged that it is a most difficult problem. He further agreed
that nitrification in streams is primarily a benthic function as a result
of some of his observations. Finally, Mr. Garland complimented the authors
on performing a useful service by calling attention to the nitrification
problem in waterways and expressed the wish that the paper would stimulate
further work on the problem.
B.2 Mr. K. Poppinghaus (Germany) led the discussion on Paper No. 67.
He was critical of the paper and questioned if the model presented could
adequately describe the complex interactions that influence the dissolved
oxygen levels in a stream. For example, he was concerned with the lack
of a factor in the model to account for reaeration from either the surface
or aquatic plants. In addition, he was concerned with the problem of
nitrification and the fact it was not considered in the model. In summary,
Mr. Poppinghaus questioned if the model, as presented, would have general
application to different waterways.
B.3 Ms. D. Brockett (New Zealand) presented the prepared discussion
for Paper No. 70. In general, she concurred with the authors and expressed
the opinion that it was a good paper. Ms. Brockett also suggested that
the semi-continuous flow culture technique may prove to be a good screen-
ing technique for toxic substances. She encouraged other researchers to
work on learning more about the technique so that either a standard method
could be developed or the technique rejected.
C. Floor Discussions
C.I Paper No. 64 initiated a lively floor discussion. Mr. W. Gujer
of Switzerland challenged the authors' failure to develop a "predictive"
model for nitrification in streams. He expressed the opinion that while
the nitrification process was complex it could be modeled in a "predictive"
fashion. Mr. Gujer then proceeded to present a "predictive" model he had
developed for a Swiss Stream. Mr. Krenkel responded that the concept
presented by Mr. Gujer was desirable for a basic research effort but would
not be practicable from an applied point of view. The use of the
"predictive" model presented would require considerable background infor-
mation that would be too costly and time-consuming to obtain in most
cases. He further expressed the opinion that the Swiss model presented
appeared to be primarily for a specific case. Mr. Gujer acknowledged
that the model had been developed for a stream with a high velocity. Mr.
Krenkel also agreed that the nitrification process was autocatalytic by
nature but practically could not be described in that manner in a complex
river situation.
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C.2 The theme of the floor discussion of Paper No. 67 questioned
the general application of the model to different streams. Mr. W. Gujer
of Switzerland requested confirmation that the model had actually been
utilized on 10 different streams. Mr. Wolf confirmed its general use
but did acknowledge that nitrification and reaeration must be taken into
consideration.
C.3 In the discussion of Paper No. 70, Mr. Ullman (West Germany)
agreed that the semi-continuous flow culture technique had the advantage
of utilizing several reactors for different variables simultaneously.
He did express concern, however, with the use of the Michaelis-Menten-
Monod equation for the kinetics of the inhibition model. He also was
concerned with the use of laboratory bioassay techniques to predict the
behavior of toxic elements in the real world. Mr. Ullman ended his
remarks with a request for the lighting conditions used in the study.
Mr. Reynolds responded that continuous flow bioassays were easier to
relate to real world problems, but that if semi-continuous flow bioassays
could be understood and adequately described they may prove an excellent
alternative. He also-defended the kinetics used in this study. He con-
cluded that the lighting conditions were the same as those recommended by
EPA, 400 ft candles + 10 percent of continuous illumination.
D. Other Observations and Comments
This session was the last of the conference which limited the
informal discussion of the material which usually occurred following the
formal presentation. This reviewer was especially impressed, however,
by the excellent attendance of the session (150 participants) considering
its position on the program. The seriousness of conference participants
was apparent.
IV. CRITIQUE OF SESSION
The session as a whole was excellent and well received by the
participants. The discussion leaders were prepared with written comments
and raised pertinent questions concerning the work presented. The con-
ference participants had, as a whole, read the pre-prints of the papers
and actively took part in the floor discussions. The authors did not
read their papers but rather used the time to introduce and expand on
the material presented in the printed paper. For example, Mr. Krenkel
described how the model had been used by the Tennessee Valley Authority
in the U.S., reviewed the analytical procedures and presented typical
nitrogenous removal rates for oxygen that did not appear in the paper.
While honest questions were raised concerning Paper No. 64, after the
discussion, the consensus of the session was positive and it was apparent
that the procedure described was ready for use.
Mr. Wolf's model for predicting the oxygen balance in a stream
(Paper No. 67) met with considerable skepticism. In his presentation, Mr.
Wolf utilized slides of rotating disks, the model 1000 m channel, as well
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as the river and streams in which the model had been successfully uti-
lized. Nevertheless, at the close of discussion there was the feeling
that the model as presented, although original, would not apply in a
broad number of cases. Mr. Poppinghaus, who led the discussion, was
especially effective in presenting his views.
Mr. Reynolds, in his presentation, briefly outlined Paper No. 70
integrating the material with a series of slides of the laboratory equip-
ment and procedures. Although a few specific items were questioned the
paper as a whole was well received. It was the feeling of the conference
participants as well as the authors that while considerable work remains
to be done with semi-continuous flow bioassays, the results of Paper No.
70 indicate definite promise.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The results of the paper entitled "Nitrification in Free-Flowing
Streams" can and should be applied to estimating dissolved oxygen levels
in this country's streams. While it is an empirical tool that works, a
better understanding of the nitrification process in streams would provide
a better tool in the future. It is suggested that basic research into
the nitrification process in rivers and streams would prove fruitful in
the future.
This reviewer questions the model developed in Paper No. 67.
Although the author presented confirmation on two rivers, it should be
noted that the actual range of dissolved oxygen values in the rivers that
the model was matched with were often in excess of 4 mg/£ and in one case
was 9 mg/£. The only apparent practical use that this model may have is
to make a first estimate of a river's dissolved oxygen profile when a mini-
mum of information is available.
The implementation of the Toxic Substances Act in the USA will
require considerable research in the future. While Paper No. 70 does not
provide the final answers concerning semi-continuous flow bioassays, it
does provide a good basic background for further study. It is now appar-
ent that a quicker and simpler standard technique for screening a large
number of toxic materials is needed. This technique appears to show
some promise for this type of work.
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I. SESSION
A. Theme of Session: Land Treatment
B. Papers Presented: Workshop - Land Treatment.
Convener: A. Wachs
Speakers: C. E. Pound (USA), I. P. Hyman (South
America), J. C-. Lance (USA), J. B.
McPherson (Australia)
II. REVIEWER
A. Name: J. C. Lance
B. Position and Affiliation:
III. Formal Papers
Research Soil Scientist, U.S. Water
Conservation Laboratory
U.S. Department of Agriculture
Phoenix, Arizona
A.I C. E. Pound (USA) discussed the long-term effects of infiltration
of wastewater into soils. He described a rapid infiltration system near
Hollister, California, where wastewater has been applied for 30 years. The
water was treated in an Imhoff tank in earlier years and now it is treated
in an unheated digester before application to flooding basins. The waste-
water from a city of about 10,000 people is now applied to 7 ha. The
total amount of water applied per year is about 30 m.
The water table depth is at about 20 m, but clay lenses cause a
perched water table above that level. About 33 kg/ha/day of N and 17.6 kg/
ha/day of P are applied. Preliminary results indicate that nitrogen
removal is significant but a quantitative estimate is not yet available.
No COD, BOD, or P from the sewage appears to have reached the deep aquifer.
A.2 J. P. Hyman (SA) discussed land disposal of mineralized efflu-
ent from pulp and paper mills. He indicated that land treatment is a
feasible method for disposal of some pulp and paper wastes.
A.3 J. C. Lance (USA) discussed nutrient and pathogen removal by
rapid and slow infiltration systems for land treatment. Some of the
practical problems in managing a high-rate system were discussed, and
then nitrogen removal by both rapid and slow infiltration systems was
discussed. Experience over the past 10 years with the Flushing Meadows
Project showed that high infiltration rates (40 to 60 cm/day) can be
maintained by intermittently flooding with cycles of 2 weeks flooding
alternated with 1 to 2 weeks drying. These rates could be maintained
without clearing the surface when the suspended solids content of the
effluent was below 10 mg/£. Soil column experiments showed that infil-
tration rates with primary effluent could be maintained at a much higher
suspended solids level (50 to 150 mg/£). Infiltration was greatly
reduced when detention in a pond allowed a buildup of algae in secondary
effluent before application in flooding basins.
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Most of the BOD, COD, and fecal coliforms were removed at all
infiltration rates. No viruses were detected in 400-£ samples concen-
trated from wells at 2-month intervals during one year. Laboratory
studies showed that the recharge basin sand has a very high adsorption
capacity for viruses.
N and P removal by high-rate systems was discussed in a pre-
vious paper by J. C. Lance. It was briefly mentioned that most of the
N and P could be removed in a rapid infiltration system by careful manage-
ment of infiltration rates and flooding and drying cycles. Denitrifica-
tion is the reaction which must be used for N removal in a high-rate
system. Crop removal is the only N removal system which has been quanti-
tatively evaluated for slow-rate of irrigation systems. Thus, only N
removal by crop removal can be accurately calculated.
Nitrogen is undoubtedly lost by devitrification but the amount
isn't known. Management practices could be developed to increase N
removal by denitrification in low-rate systems. Significant amounts of
N could be stored in soil organic natter when primary effluent, raw sewage,
or cannery plant effluents are applied, but the amount stored when secon-
dary effluent is applied is probably very little. Storage of Nfy-N cation
exchange is temporary but important in slowing the movement of N through
soils.
A.4 J. P. McPherson (Australia) described the Werribee farm land
treatment system in Melbourne. The farm treats sewage from about 1.6
million people at an annual cost of $2.60/person ($3.25 U.S.). Raw sewage
is applied by flood irrigation to pasture land during the summer and the
grass is grazed by beef cattle and sheep. About 10 cm of sewage is
applied every 18 to 20 days, with an average of 105 cm/yr. The water
which moves through the soil is collected in drainage ditches and released
into Port Philip Bay. The reduction of BOD, N and P is more than 90 percent.
The land irrigated with raw sewage during the summer is not used
during the winter. Instead an overland flow system is used on another
area of very slowly permeable soils. The water applied to the overland
flow system is first passed through sedimentation tanks. The removal of
N is about 60 percent, and P removal is about 35 to 40 percent. BOD removal
is more than 90 percent.
The two land treatment systems handle about one-half of the
total flow of sewage water entering the Werribee farm system. The remain-
ing half is treated in lagoons. The water passes through a series of
lagoons before release into the bay.
Beef cattle are bred on the Werribee farm and sold to help reduce
the cost of the system. Sheep are bought in the spring and sold in the
fall to complement the beef production system. Every carcass of beef from
the Werribee farm is inspected and no health problems have been encountered.
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B. Prepared Discussions
These were not used in the Workshop format.
C. Floor Discussions
H. I. Shuval presented information from irrigation systems in
Israel showing that crop production was excellent with sewage water irri-
gated fields. He noted that sewage has been applied by trickle irrigation
near Elat. Enteroviruses survived in the wet area around the trickle
emitters for about 2 weeks. Crops were not contaminated when the wetted
soil was covered with plastic. He also presented some data, which he had
shown earlier in the week, showing that the disease rate in villages near
sewage farms in Israel was higher than in other areas.
Noonan commented that fecal coliforms moved about 900 m in the
groundwater from an application site in Canterbury, New Zealand. The
soils used were very coarse sands and gravels. The amount of nitrogen
in the groundwater was already high and changes after sewage application
could not be detected.
Pound, in response to a question from the floor, noted that
boron could present a problem in irrigating some crops if its concen-
tration in sewage is more than 1 ppm.
Lance, in summarizing the discussion of various land treatment
systems, suggested that the local situation should determine the kind of
land treatment used. Low-rate systems require large areas of land devoted
to crops which can be utilized without a disease hazard. Rapid infiltration
systems require highly permeable soils. Water from high-rate systems can
be reused for irrigation, recreational lakes, or industry. Overland flow
systems can be used on impermeable soils where no other land treatment
system is feasible. In some cases it may be desirable to use a combina-
tion of different systems. For example, water could be treated in a high-
rate system and then used for unrestricted irrigation.
D. Other Observations and Comments
The discussion from the floor and informal discussions indicate
that some people still do not understand what really happens when sewage
is added to soil. Many people assume that the continued application of
sewage will result in an accumulation of organic matter, fecal bacteria,
or salts which will clog the soil and curtail the life of the system.
This is a question which is asked at almost every meeting on land treat-
ment. We must continue to try to communicate the fact that a properly
operated system with resting periods for oxidation of organic matter,
nitrification, etc. can be used indefinitely. Hopefully, reports on
systems used for many years will help to solve this problem.
The movement of viruses through the soil to groundwater is a
matter of concern to many. Reports of movement through some soils and
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lack of movement In others has created confusion. More work is needed
on virus adsorption by various different soils to clear up this confusion.
At the present time, the reports of movement through several feet of soil
have been for coarse soils and gravels. Adsorption was high for the loamy
sand (2 to 3 percent clay) used in our experiments at the Water Conservation
Laboratory. Probably virus adsorption is even higher for mineral soils
which are finer in texture than a loamy sand. Exactly how many feet of
travel are needed under various management practices needs to be established.
Also, I have the impression that reports showing virus movement have led
some people to think that viruses move through most soils. Actually, the
experimental data show that viruses probably do not move through soils except
in special cases like very coarse sands, possibly some organic soils, and
others which need to be identified.
Several people in private discussions voiced the fear that the
epidemiological report by Shuval may be misinterpreted. This report has
been approved for publication in Science and may have a "headline" effect.
Some important points were not mentioned in the oral reports by Shuval and
may not be included in the published paper. First, the water used for
irrigation was almost the equivalent of raw sewage. It had received 5 to
6 days detention time in oxidation ponds. Also, the level of enteric
disease organisms in sewage in Israel is often orders of magnitude higher
than the maximum levels reported in the United States. This is due to
the fact that less water is used in collecting sewage in Israel and thus
the sewage is more concentrated. Also, Shuval stated that the incidence
of enteric diseases in the areas served by the sewage treatment system is
higher than in the United States. It is unlikely that raw sewage would
be used for spray irrigation in the United States. Even if raw sewage
was used, the enteric pathogen level in the water probably would be con-
siderably lower than in the water used in Israel. Therefore, it is doubt-
ful that the results from this report could be applied to the United States.
This does not mean that the data are not valid but simply that experimental
conditions were much different than in the United States. The results do
apply to Israel and probably to many other countries.
In private conversation McPherson indicated that a check of
absentee records for the Werribee farm employees during 1975 showed a
lower rate of absenteeism for farm employees than for other employees of
the Melbourne and Metropolitan Board of Works. This does not carry the
weight of an epidemiological study, but this data, along with the long
experience of Werribee, indicates that this system has not created a health
problem for its employees or nearby residents.
IV. CRITIQUE OF SESSION
Many people attending the meetings were interested in answers
to practical problems which they could not obtain from formal papers. I
think that at least some of these questions were answered by the Workshop.
The presentations were well organized and appeared to be well received
by the audience. Much information was presented on rapid infiltration
systems and this seems appropriate since these systems are not always
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discussed in land treatment sessions. Since land treatment technology
can be applied in both developed and developing nations, such workshops
are a valuable part of international meetings.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The results reported at the Workshop indicate that land treatment
may be used in many cases to prevent water pollution. Of course, it can't
be used in every situation. More information needs to be developed to
assist in determining the best system to use. This would include instruc-
tions on how to use the soils data available from the Soil Conservation
Service to determine what kind of land treatment system, if any, could be
used for a particular location. Also, it is obvious that more data on
economic comparisons of different sewage treatment systems are needed.
This meeting and other similar ones show that more work needs to
be done on the management of land treatment systems. Many systems have
been monitored to determine the removal of pathogens and nutrients, but
in most cases little work has been done on ways to improve land treatment
systems. Field and laboratory work in conjunction with the Flushing Meadows
project has shown that the treatment can be drastically changed by different
management practices and that there is great potential for further develop-
ment of land treatment systems. Also, more work is needed on the way dif-
ferent soils respond to applications of sewage. For example, little is
known about movement of viruses through many of the soils available for
land treatment. The effect of different soil characteristics on various
treatment aspects needs more attention. This would facilitate the transfer
of information between locations. Also, the effect of climate on various
treatment systems needs more attention.
In summary, this Workshop shows that many land treatment systems
have been successful for long periods of time. This shows that further
application of our knowledge of the physical, chemical, and biological
processes operating in soils and further experimentation should greatly
increase the usefulness of land treatment as a method to prevent water
pollution.
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I. SESSION
A. Theme of Session: Removal of Organics
B. Paper Presented: 59. Removal of Organics in Sewage and
Secondary Effluent by Reverse Osmosis.
E. S. K. Chian, S. S. Cheng, F. B. DeWalle
(USA)
II. REVIEWER
A. Name: E. Robert Baumarm
B. Position and Affiliation: Professor of Civil Engineering
Iowa State University
Ames, Iowa 50011
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 59
Reverse osmosis is a versatile separation-purification process
for separating pollutants from industrial and advanced water and waste-
water plant effluents. Most research emphasis has been on removal of
inorganics, but recently Chian at Illinois began a study of RO character-
istics for removal of organics. The understanding of the basic mechanics
involved in separation of organics by such membranes would improve process
design.
Separation of organics by RO membranes depends on the molecular
sieve characteristics of the membrane and on the characteristics of the
organic molecule. The membrane sieve characteristics affect the degree
to which organic molecules are removed and.the rate at which purified
water (flux) is produced.
The removal of organics from wastewaters is dependent on the
operation of previous biological treatment units because this determines
the molecular weight distribution and nature of the organics present. How-
ever, little has been known about 1} the organic compounds in activated
sludge (AS) effluents, and 2) the relation between operating parameters of
AS units and the organics in the treated wastewaters. The purpose of this
study was to operate AS units at two loadings (F/M ratios of 0.33 and 0.69)
and remove organics from the AS effluents using RO so that organics removal
could be correlated with AS unit operation. Specifically, the study classi-
fied the organics by particle size and molecular weight (by gel permeation)
and by identification of the organic chemical composition (gc-mass spec.).
Two AS laboratory units were operated on domestic sewage at F/M
loadings of 0.33 and 0.69 g BOD/g MLVSS-day"1 for two to three months to
assure equilibrium conditions to develop. A 3-day batch composite raw and
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treated effluent was collected and subjected to tertiary treatment by RO.
The wastewaters were first centrifuged (12,500 rpm) and filtered through
0.45 ym membranes for removal of suspended solids and microorganisms.
The filtrate was concentrated by ultrafiltration (UF) using a membrane
having a MW cut-off of 18,000. The UF permeate was subjected to RO treat-
ment using a membrane having a MW cut-off of about 150. UF processes
operated at 28 psi; RO processes operated at 750 psi at 25°C.
All wastewater samples were examined for MW distribution of the
orgam'cs to estimation of their apparent molecular weight (AMW). The
RO permeate analysis was conducted using gas chromatography for compound
separation and were identified using a mass spectrometer.
The AS units provided treatment results as follows:
F/M = 0.33 F/M = 0.69
Raw BODg, mg/£ 178 178
Effluent BOD5, mg/£ 4.1 5.3
Raw TOC, mg/£ 12.9 72.9
Effluent TOC, mq/i 14.2 (11.1 soluble) 24.1 (18.0 soluble)
The BOD removal was nearly equal in both units, but TOC removal varied sig-
nificantly with the lower loaded unit providirig best performance.
The results of MW distribution in the AS, UF and RO effluents
indicated that the unit efficiency is highest in the removal of the lowest
MW fraction. The efficiency of removal of a given MW distribution decreases
as the MW of the organics in each fraction increases. In all cases, the
percentage removal of organics is highest for wastewaters treated in the
low loading (F/M = 0.33) unit. The changes in the percentage distribution
of MW is not the result just of a change in the size of the organic mater-
ial, but involves a complex change in organic species as a result of bio-
logical activities associated with the AS units.
Separation of the organics in both sewage and effluent from both
AS units by gel permeation indicated that there exist two apparent TOC
peaks in the UF retentate and only one in the RO retentate. The apparent
molecular weight (AMW) distribution of each of the UF and RO retentates
was computed. The TOC recovery after the gel permeation experiments was
determined. The results shown in Table 3 (from original paper) indicate
that the AMW in the RO retentate appears to increase as the AS cell residence
time increases. The MW also increases with decreasing F/M ratio in the
UF retentate.
The most interesting finding in the study is the fact that the
F/M ratio operating parameters are closely related to the quality of the
effluent which can be produced by RO.
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Table 3*
Apparent Molecular Weight Distribution (Dextran) of
Soluble Organics in Representative Samples as
Percentage of Initial TOC of Samples**
Sample
Sewage
MW
Effluent
(F/M = 0.69)
MW
Effluent
(F/M = 0.33)
MW
UF Retentate RO Retentate
28.8%
12.4% 3.1% 13.3%
>50 K 2-5 K -v.2 K
(102)***
42.2%
18.1% 24.1%
>50 K *2 K
(99.5)
52.2%
28.3% 3.9% 19%
>50 K 5-50 K 2-5 K
(102)
41.3%
^150
(97.7)
40.6%
200
(99.9)
41.5%
250
(100)
RO Permeate
29.9%
<150
(99.4)
17.2%
<150
6.3%
<150
*Table from original paper
**See Table 2 (original paper) for initial TOC of these soluble fractions
***Numbers in parentheses indicate the average percentage of TOC recovered
from the Sephadex G-75 and G-25 columns
The following conclusions were drawn:
1. The operational parameter, i.e., the F/M ratio in the operation
of an AS unit, is very important in affecting the organic
content in an RO effluent. The highest RO permeate quality is
obtained with the lowest F/M ratio.
2. The RO units should only be operated on AS effluents operated
at low loadings using filtered wastewater to eliminate membrane
fouling.
3. Gross MW size fractionation studies of the organic matter must
be complemented with gel permeation studies to relate MW dis-
tribution of the organic matter in secondary effluents to its
removal by RO.
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4. The quality of the RO permeate treating wastewater from low
loading AS units was comparable to distilled water.
B. Prepared Discussion
The formal discusser, M. A. Baud of France, did not attend the
conference. The name of the formal discusser is not known to the reviewer.
This work represents a turning point in the study of RO and, in
particular, the removal of organics by RO. It is not a simple application
of RO to wastewater upgrading with mundane, standardized process evaluations.
Three new, unique, and significant techniques were carried out simultaneously
in the same study:
1. Use of new techniques to the field for determination of the
relative distribution of soluble organics in wastewaters.
2. Application of these techniques to provide data for a study
of AS process efficiency in providing effluents suitable for
subsequent RO treatment.
3. Determination of the possible effect of F/M ratio in operation
of AS units for improving the efficiency of UF and RO units in
organics removal.
The paper is very clear and precise in describing apparatus and techniques
so that others should be able to reproduce the authors' results and use
the techniques in their own work. The authors demonstrated that studies
in all three areas could be conducted simultaneously to provide a signifi-
cant improvement in study results.
Two areas of potential study deserve attention:
1. All biological breakdown processes break down the MW of the
soluble organics and therefore increase the biodegradability
of the organics.
2. Physical-chemical processes used for tertiary treatment (acti-
vated carbon, macroreticular resins, RO) all have better output
efficiency with large MW organics.
So, how can we keep the large MW organics suitable for removal using
physical-chemical processes? The discusser had several questions:
1. Although the percentage recovery reached in the AMW studies
reached 100 percent, can we wonder about the loss of volatile
materials?
2. Would not an additional extraction be helpful to get an addi-
tional MW range?
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3. Should not the methods be expanded to evaluate what goes on
using other processes, such as activated carbon adsorption?
C. Floor Discussions
Wechsler (Australia). Several questions were raised:
1. If it is important to remove SS prior to RO units, is the
problem with bacterial slimes?
2. Why did the authors use hollow fibers if the maintenance of
flux is a problem with SS?
3. Can you identify the RO peak?
Peter Gibbs (Australia). The University of New South Wales has
operated an extended aeration plant followed by UF (12 ft2) for solids/
fluids separation. Using a synthetic sewage with a BOD of 200-300 mg/£
and a F/M ratio of 0.12 day'1, the unit provided 80-85 percent BOD removal
and the BOD of the ultrafiltrate was about 30 mg/t. The pilot plant was
operated at 4.5 £/hr to a 45 psi drop on the UF'unit. This work has
been published. (?) What was the dependable flux on the authors' RO unit?
T. Waldmeyer (UK), the recorder. I had hoped for more discussion
of low MW organics. In 1970-71, the UK Stevenage Lab studied this problem.
Their main effort was to determine methods and techniques for identification
of organics. Using high pressure liquid chromatography, they identified
almost 90 percent of sewage organics - mostly sugars, low MW volatile acids,
detergent residues, ureas, etc. Stevenage has operated a pilot RO unit
for 12 months (still going) by use of a warm detergent cleaning solution.
However, the original promise of RO has not been fulfilled. The only UK
application of significance is in the dairy industry for whey recovery.
E. A. Pearson (US). It becomes very clear that attention must
be directed to the species effectiveness of RO processes. The real interest
is in the removal of specific organics, not BOD or TOC. California has
pending regulations which would require all recharged wastewater to be
treated with all tertiary processes, including RO.
What is the real cost of a 10 MGD RO process? What is the
membrane cost as a percentage of total cost?
Reply - We have completed studies to show the biological break-
down of organics. Long time AS with SRT of 20 days will reduce organic MW
to the level where RO is of no value. The suspended solids removal prior
to RO should include alum mix, clarification, granular media filtration,
and pH adjustment to 8 to 9. UF is good for removal of suspended solids
and UF and RO in series make a good team for that purpose. We used hollow
fiber which does require more suspended solids removal by pretreatment.
With tubular units, pretreatment costs are reduced. It is really only a
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problem of economics which determines which you use. The results of
organics removal are not affected.
We are using the paper's techniques to look at trace organics
in drinking water. Illinois has six postdoctoral staff members at work
on a $500,000 per year study. The cost of a 130 MGD plant at Yuma,
Arizona, was $60,000,000 for the AS system and $60,000,000 more for RO
treatment. Total operating cost is 50-60^/1000 gal. We have studied
rejection of 500 compounds by RO. Small plant construction costs will
be about $1/gal/day and operating costs will be about$1.50/1000 gal.
IV. CRITIQUE OF SESSION
This paper was, by general consensus, one of the two or three
best papers presented at the conference. The techniques used to classify
MW ranges and to evaluate RO performance are not well known or frequently
used in the field. The results confirm the importance of making more
detailed process evaluations prior to mass movement to new processes.
The authors are to be commended for a particularly interesting,
effective presentation.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The techniques used in this paper are important in evaluating
what effects prior biological treatment will have on several tertiary
treatment processes such as use of activated carbon or XAD resins for
organics removal. Studies should be conducted to evaluate their perfor-
mance in studies similar to those reported in this paper.
Unfortunately, few universities or treatment plants will have the
requisite trained chemists and the expensive equipment necessary for con-
ducting studies of this type. It will be deplorable if everyone rushes in
to cash in on the technique. Only three or four groups in the U.S. should
probably be supported in this area of work; one should be in EPA's own
laboratories.
The ability to identify AMW ranges is not as important as the
ability to identify specific compounds. Grants should be made to provide
general support of a long term nature to three or four groups for work in
this field.
The study reveals very effectively the conclusion that for
"optimization" of total wastewater control we need to develop models for
prediction of what happens to organic compounds in waste streams, not
just BOD and/or TOC.
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I. SESSION
A. Theme of Session: Tertiary Wastewater Treatment
B. Paper Presented: 62. Series Intermittent Sand Filtration to
Upgrade Wastewater Lagoon EFfluent.
D. W. Hill, J. H. Reynolds, S. E. Harris,
D. S. Filip, E. J. Middlebrooks (USA)
II. REVIEWER
A. Name: E. Robert Baumann
B. Position and Affiliation: Professor of Civil Engineering
Iowa State University
Ames, Iowa 50010
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 62
The purpose of the study reported was to develop design criteria
for intermittent sand filters used to polish lagoon effluents. Most
lagoons now are required to provide an effluent BODs below 30 mg/£; Utah
now requires that lagoon effluent BODs be ]ess tnan 5 m9/£- Previous
studies at Utah State had indicated that single-stage intermittent sand
filters provided a simple, economical, reliable method of wastewater treat-
ment but the filters used resulted in very short filter runs (14-42 days)
and operating problems. This study, therefore, was directed at evaluation
of series operation of intermittent filters using larger media in the
first filter with the specific purpose of increasing the length of filter
run for "optimization" of the process.
To evaluate the effectiveness of series intermittent sand fil-
tration of lagoon effluents, nine 16-sq ft surface area filters in three
sets of three filters in series were operated at different loading rates.
The three sets of series filters all had 0.762 m of sand and 30.48 cm of
gravel on the bottom for a drain. The sand sizes were:
1st filter in set - 0.72 mm
2nd filter in set - 0.40 mm
3rd filter in set - 0.17 mm
The hydraulic loading rates used were 0.5, 1.0, and 1.5 mgad (4,700;
9,350; and 14,000 m^/hectare-day). {Uniformity coefficient of sand was
not recorded. The filter media was uniformly distributed in the filter.)
Samples of filter influent (lagoon effluent) and filter effluent from
each filter in the series were collected weekly and analyzed for BOD, SS,
VSS, pH, temperature and dissolved oxygen from the period July 23 to
December 2, 1974. The system was shut down without termination of any
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filter run after 130 days due to freeze-up of the waste lines from the
Logan Municipal Sewage Lagoon to the study filters.
Figures and tables are provided in the paper to tabulate the
filter operating results. Studies of algae present in the samples indi-
cated that a small, coccoid blue-green algae (Apfeanocapaa AJO.) was the
predominant algae. Total algal populations in the lagoon effluent varied
from 5,000 to 275,000 cells per mi.
All filters were still in operation after 130 days; thus, none
were run to failure. The dosing cycle (remember, these are intermittent
sand filters) was not described, but the "applied influent load passed
completely through all three filters" in a set within four hours.
Lagoon effluent BOD varied between 4.1 and 23.4 mg/l. The 1.5
mgad loaded filter produced an effluent BOD between 0.6 and 4.1 mg/£.
Filter efficiency increased with run length due to the buildup of a sur-
face layer of solids on "each" filter. Mean BOD levels in mg/£ on the
highest loaded filter set were:
Lagoon effluent - 10.5
1st filter effluent - 8.2
2nd filter effluent - 5.8
3rd filter effluent - 2.3
Lagoon effluent suspended solids levels varied between 12.5 and
69.4 ng/t and averaged 31.7 mg/£. The average results on the filters with
highest mgad loading rates were:
Lagoon effluent SS, mg/£ - 31.7
1st filter effluent SS, mg/e - 16.1 (0.72 mm sand)
2nd filter effluent SS, mg/£ - 14.1 (0.40 mm sand)
3rd filter effluent SS, mg/£ - 6.4 (0.17 mm sand)
Again, suspended solids removal improved as the filter run progressed due
to buildup of solids on the filter surface.
Mean volatile solids levels, in mg/£, from the highest loaded
filter set were:
Lagoon effluent - 21.3
1st filter effluent - 9.8
2nd filter effluent - 7.0
3rd filter effluent - 3.3
The tests conducted using a lightly loaded lagoon effluent
indicated that series intermittent sand filters (3) could produce an
effluent BOD less than 3 mg/£, effluent SS less than 9 mg/£, and effluent
VSS less than 4 mg/£ at a loading rate of 1.5 mgad with a run longer than
130 days.
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The authors recommended design criteria as follows:
Hydraulic rate - 1.5 mgad (14,000 m3/hectare-day)
(Flow rate divided by area of a single filter)
Filter sand size, mm - 1st filter - 0.65-0.70 (special processing)
- 2nd filter - 0.35-0.45 (special processing)
- 3rd filter - 0.15-0.25 (pit run sand)
Uniformity coefficient - 2 to 10
Filter bed - 0.914 m of sand (minimum of 0.61 m),
0.304 m of 1.27-2.54 cm gravel;
drains embedded in the gravel
Sand cleaning - hydraulic backwash after removal from
the bed
Embankment - same as for lagoon system
Influent-effluent drain system - size to dose filters in less than 6 hr
Operation mode - hold lagoon effluents during peak
algal loads; load filters at night
Total operating costs of series intermittent lagoons were esti-
mated to be $67-70 per million gallons of filtrate.
B. Prepared Discussion
The appointed discusser of this paper (G. Shelef, Israel) commented
and raised the following questions:
1. He could argue the validity of the effluent standards, but if
the treatment cost is only 6-74/1000 gal, he concluded that
lagoons followed by series intermittent sand filters was a
sound-logical design approach.
2. The quality of the Logan, Utah, lagoon effluent was already
superior to that required in Israel which are operated at far
higher loading rates. Since the algae themselves have a low
BOD, they should not be limited by an SS limits imposed. Do
you agree?
3. In Utah, the most prolific algal species encountered is also
the one that is most easily filtered out. What happens when
a difficult filtering algal species is encountered, as they
are yearly in Israel?
4. Why were no fecal coliform determinations made in the study?
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5. The filtration system itself for the purpose outlined can take
many forms. In Israel, sand dunes have been successfully used.
C. Floor Discussions
Dahlem (West Germany). In Table 1 in the paper, the zooplankton
dimension is not given. What Zooplankton prevail?
Ben-Harim (Israel). You reported filtration rates up to 1.5
mgad. Did you use higher rates?
Participant (West Australia). Intermittent sand filters have
been used for over 100 years. Aren't you confusing the issue by reinvent-
ing them? Why not put all your different sized media in layers in one
filter?
Baumann (USA). The cleaning of series intermittent sand filters
is based on scraping off the surface film that forms. Yet, your data
demonstrate clearly that solids do penetrate the media and that there
must be depth removal of such solids. Have you given any thought to the
fact that in 5 or 10 years the filter may have to be completely rebuilt
due to the progressive nature of such clogging?
Reply - Intermittent sand filters are not new and the authors
have never claimed them to be. We are merely applying an old process to
a new problem and we are trying to define how this can be done successfully.
In the study, a 5-cell series lagoon was used to supply waste-
water by drawing effluent from the second lagoon. Therefore, our lagoon
site was a poor choice since the wastewater quality is so good without
filter treatment. We have encountered small algal species and had them
removed by our filters. I know, however, of an Oregon plant where very
small algal cells are not removed in a filter like ours. Coliform removal
was uniformly high, with effluent counts below 100/100 mi. We have heard
that operation of series intermittent filters for two days with two days
of rest would eliminate the need for cleaning. We tried it; the filters
require cleaning.
Layering of the filter media in one filter unit would provide an
interface where surface (interface) removal would occur at a place we
cannot get at to remove it. In our experience, most of the solids removal
is at the surface and we - at least in our study periods - have not had
problems with depth removals of the suspended solids. The zooplankton
were principally daphia. We have tried loading rates to 16 mgad, but run
lengths are seriously reduced at rates over 3 mgad; the effluent quality
is not degraded significantly.
Waldmeyer (UK). British experience indicates that series inter-
mittent sand filters require that a very high quality of effluent be applied
to them before they will perform satisfactorily over the long term.
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IV. CRITIQUE OF SESSION
This paper does outline the application of an old process for
solving a current problem, the upgrading of lagoon effluents. The study
conducted did not generate any real enthusiasm on the part of the audience,
particularly with those who have familiarity with lagoons or with filters.
The results of the study as reported suffer severely from the following
limitations:
1. The lagoon selected for use in the study is definitely not
representative of a normally loaded lagoon.
2. The study was made with only three media sizes and at only
three wastewater application rates. At no stretch of the
imagination could we conclude that sand size, sand depth, and
wastewater application rates are anywhere near at optimum
criteria.
3. The filter runs were not conducted through even one cycle,
since the filters never needed cleaning. How can we be sure
that continued cleaning of only the surface would leave the
solids removed with depth still in place and ultimately in
1-2-3-4 years cause complete failure of the system? No pro-
visions are made for depth cleaning of the media.
4. Thus, the extrapolation of results from this study to estab-
lish general design requirements would be tenuous at best.
5. It would appear desirable that plant-scale installations be
made on normally and overloaded lagoons to observe the opera-
ting characteristics of series-intermediate filters over a
period of years and the results recorded and reported. Instal-
lations should be made on both storage lagoons (as at Iowa where
all wastewater is stored from about December 1 to April 1) and
flow through lagoons. This reviewer would expect real problems
to develop! Conversations with Australian, British, and Israeli
conference representatives indicated that they had the same fears.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Series intermittent sand filters used for polishing of lagoon
effluents represents the application of an old process for solution of a
new problem. The filters obviously can work. The filters obviously will
ultimately clog and need complete rebuilding. We do not have good data
to optimize design. We do not have "real plant" operating experience to
indicate confirmation of the pilot plant results reported in the paper.
The technique, however, has real merit in that it is a low energy,
low labor, cost effective (barring rebuilding needs) method of removing
algal cells and residual BOD from lagoon effluents.
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This reviewer presently is concerned about discharge of algal
cells from lagoons not because of the BOD discharged to the river but
because the algal cells constitute a continuous source of seed into
waters containing loads of nitrates and phosphates (in Iowa, anyhow)
from agricultural runoff. Our only major aimiom'a fishkill occurred with
a spring lagoon emptying with plankton counts of over 1,000,000 cells/mi.
These cells hit the Racoon River where plankton counts increased 2 or 3
times in the 15 miles below the discharge point sending the pH of the
river from 7.5 to at least 9.3-9.4. The ammonia level in the river from
the lagoon was in the range of 10-15 mg/£. Fish kill was inevitable. We
must give consideration to removal of such algal cells from lagoon dis-
charges. We need better information on the feasibility of long-term
service of series, intermittent sand filters for this purpose.
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I. SESSION
A. Theme of Session: Ion Exchange
B. Papers Presented: 65. Ion Exchange in a Moving Bed of
Magnetized Resin.
B. A. Bolto, D. R. Dixon, A. J. Priestley,
E. A. Swinton (Australia)
68. Recovery of Zinc using Chelating Resin.
H. Uejima, M. Hirai, T. Ishibashi (Japan)
71. Water Demineralization by a Thermally
Regenerable Ion Exchange.
B. A. Bolto, N. H. Pilkington, P. M. Sharpies,
G. K. Stephens, K. 0. Wade, D. E. Weiss
(Australia)
II. REVIEWER
A. Name: Alan H. Molof
B. Position and Affiliation: Associate Professor of Civil Engineering
Polytechnic Institute of New York
Brooklyn, NY 11201
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 65
The paper given by Dr. Priestly covered three main areas. These
were:
1. Structure of a typical magnetic resin
2. Dealkalization process using weak acid magnetic resin
3. Entrained flow pipe line as the adsorber (ion exchange) vessel
The structure of a typical magnetic resin consists of an inert
polymeric core of cross-linked polyvinyl alcohol in which is distributed
fine particles of magnetic gamma iron oxide. Around the core is grafted
the shell of the resin material. In this case the weak acid resin is
polyacrylic acid.
The unmagnetized form has a settled slurry voidage of 0.33.
Upon magnetization the magnetized resins form into ringlets of higher
void volume. Settling produces a slurry with a voidage of about 0.4
which allows easy transfer by pumping with low resin attrition and low
pressure drop.
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A dramatic increase in settling rate occurs upon magnetization.
The settling rate of the fine size magnetic particle (60-70 ym) is equal
or greater than much larger size conventional resins. This property allows
separation in simple settling tanks and wet magnetic separators and also
allows use in fluidizedbeds at a relatively high superficial velocity.
The small particle size results in rapid ion exchange. With weak
acid resin there is an increase of about 6 to 7x over conventional Amberlite
IRC-84.
One of the first uses of the magnetic resin was in the dealkaliza-
tion of a hard alkaline bore water using a weak acid resin form. In this
reaction there is a simultaneous removal of hardness and alkalinity in one
reaction. The process flow diagram consisted of a vigorous fluidized bed
for the exchange vessel and an incipient fluidized bed for the regeneration
vessel. For regeneration the flow was counter current with the resin down
and the acid up. The exchange column ID was 30 cm and the regeneration
column 13 cm with a flow of 30 £/day. An eductor was used for physical
transport with little physical attrition.
There was essentially complete dealkalization with concurrent
calcium removal and a small amount of sodium removed. Compared to results
with more complicated continuous ion exchange processes, the magnetic resin
process obtained the same degree of dealkalization but with simpler equip-
ment, less resin, higher concentration in effluent and lower flow rate.
Application of the magnetic resin process to wastewater treatment
would require equipment to handle highly turbid waters with small particle
resins. Fluidized bed was not found satisfactory. The proposed alternate
was an entrained pipeline in which the resin is carried in turbulent flow.
The feed and resin flow are concurrent to a settling tank where
the settled resin is transferred to a pipeline regeneration with acid. The
regenerated resin goes to a water separator and wash such as a vacuum fil-
ter. The washed regenerated resin is returned to the exchange section.
The equipment is simple except for the vacuum filter. However, the high
filter rates would result in small size filters.
A cost comparison shows the entrained flow pipeline process to
require the least volume for exchange and the smallest resin inventory for
the several alternates considered. The capital cost was estimated to be
half of the equivalent fluidized bed process.
A pilot plant was used at a physical-chemical plant handling
primary settled wastewater. The feed was from the base of the ammonia
stripping tower following lime coagulation. The pipeline was 60 m long
with a 2.54 cm ID plastic pipe. The velocity at 0.7-0.8 m/sec was suf-
ficient to fully entrain the resin.
The results showed rapid dealkalization with a contact time
of 70-80 sec to lower the alkalinity to low levels. The results were
more rapid than that predicted from a previous design study. It was
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thought this was due to the turbulence pulling the floes apart exposing
more exchange area. The entrained flow pipeline in a large scale appli-
cation would require a 75 cm ID pipe with a velocity of 1.2 m/sec for a
45 M£/day (10 mgd) flow. Advantages included simplicity, no high pressure,
no blocking of streams, less resin, small plant and no preclarification
needed.
A.2 Paper No. 68
This is a report on the use of a chelating resin, Unitika UR-10,
to remove zincfroman industrial waste and concentrate it sufficiently so
that the zinc can be reused in the polyvinyl alcohol fiber process. There
is a high calcium and sodium content compared to zinc requiring a high
selectivity resin such as UR-10. After the metal is removed, the organic
material in the waste (formalin) at 580 mg/£ is treated by activated
sludge. The resin selectivity coefficient for ZN was 12 and for Ca was 1.
The zinc must be a concentration of at least 96 percent based
on a zinc-calcium mixture. The normal zinc recovery is as high as 88
percent. Therefore, a major process development was required to raise
the zinc removal in the presence of calcium. The wastewater had a pH
1-2; zinc, 21.5 mg/£, calcium, 76 mg/£; sodium, 600 mg/£; iron, 0.7 mg/£;
copper, 0.2 mg/£; and formalin, 580 mg/£.
The first scale was a laboratory level using a 1.5 cm resin
column. The operation cycle was: sodium salt form, adsorption of Zn,
elution with acid, and regeneration with NaOH. The total adsorption
capacity of the resin was 0.6 mol/£-RNa. The best pH was 5-6.
Calcium having a low selective adsorption was affected by
sodium significantly more than was Zn. This fact was used as the basis
of raising the purity of the recovered Zn.
One test passing the wastewater through the resin followed by
acid elution yielded a zinc/calcium weight ratio of 80:20. If a zinc
sulfate solution (250 mg/£ Zn) was passed through the resin before the
acid elution, purity of the recovered Zn in the acid elution reached as
high as 97 percent. The acid was H2S04.
The first process scale-up was to the middle scale with a 70 cm
diameter resin column 153 cm high. The process had neutralization followed
by a filter and the resin column. To avoid problems resulting from the
resin reducing its volume by 25 percent when the metal was adsorbed, a
limit of 0.5 mg/£ suspended solids at a space velocity of 25 was required.
The suspended solids were mainly from hydroxide and CaS04 at 5-20 mg/£
from the neutralization. A limit of 2 mg/l Zn in the effluent was moni-
tored. This was done by a chemical indication test developed by the
authors for this particular waste.
The second scale-up was to the full scale plant with a wastewater
flow of 100-120 m3/hr, 15-20 times as much as the middle scale. The Zn
was almost completely recovered and the Zn content of the eluate was high
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enough for reuse. The iron and copper were reduced to nondetectable
levels. The activated sludge plant yielded a 95 percent COD removal.
A.3 Paper No. 71
The process described is for removing small quantities of salt
from large volumes of water. The feed water is mildly brackish up to
3000 mg/£ total dissolved solids (TDS). The main advantage of the process
is the ability to regenerate the resin with hot water, the cheapest
regenerate. The resin and process are called Sirotherm. A commercial
plant is in operation and the resins are being distributed around the
world. Testing started in 1973.
The resin is a mixture of weak acid and weak base groups to
adsorb cations and anions respectively. The hydrogen and hydroxide for
regeneration is supplied by the hot water. The equipment is conventional,
fixed or moving bed, co- or counter-current regeneration.
The first full scale plant removes 80 percent salinity with a
feed of 400-600 mg/£ in Adelaide, South Australia. The flow is 600 m3/day
and the process acts as a pretreatment for boiler feed water.
The flow sheet consists of: alum coagulation and filtration,
ion exchange organic trap column, strong acid resin softening regeneration
with Nad, H2$04 to pH 3.8, vacuum degasser tower, pH adjustment by caustic
to neutral, and Sirotherm column. The acid destroys the alkalinity and
the liberated C02 and dissolved oxygen are removed in the degassing tower.
Neutral pH is a requirement for the feed. Removal of dissolved oxygen is
also required since the resins will be slowly oxidized at the elevated
temperature of regeneration.
Another major application of the process is in the renovation
of wastewater for reuse. The typical salt content is 1000-2000 mg/£ TDS.
Organic fouling is a major problem since it reduces capacity at
a rate too rapid for practical purposes. The capacity loss was not per-
manent since it was possible to renew the resin by caustic and brine
chemical regeneration. By using a pretreatment of a conventional organic
trap resin to remove organics not removed by activated carbon, the fouling
organics were captured (MW 1000-10,000) and the Sirotherm capacity was not
reduced.
A 20 m3/day pilot plant similar to that used in Adelaide was
used in Japan where reuse is a very high priority. The pilot plant fol-
lowed an activated sludge plant with tertiary treatment including carbon.
There were dramatic changes in salt feed levels over the 1000 cycles of
operation with 3-5 mg/£ COD in the Sirotherm feed.
The advantages of the process include cost, i.e., cheapest
energy for regeneration (low grade heat 80-90°C), minimum chemical pollu-
tion, offers large interfacial area and has low capital and operating costs.
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B. Prepared Discussion
B.I According to the discusser (A. D. Carr, South Africa), they are
doing work at Capetown on treatment of secondary effluent to produce
potable water. Part of the treatment is a vertical multi-stage continuous
ion exchange column. At the start each stage is half full of resin. In
the upflow cycle when loading the column the resin in each stage is fluid-
ized for about 4 min. Then the resin is settled and transferred to the
stage below.
After several cycles, the resin will deplete at the bottom stage
and overfill at the top stage. The problem comes from the density ratio
of the resin/solution which is 1.06 at the top and 1.2 at the bottom. If
a heavy resin such as the magnetic resin could be used, the resin problem
could be solved. The first question was - is it possible to use the mag-
netic resin in equipment such as the vertical multi-stage column with a
short period for settling and transfer of resin of about a half minute?
If not, is there any basic disadvantage to making a larger resin?
In multi-stage operation, the kinetic advantage of small size
resins is often lost due to time constraints externally posed, i.e., the
rate of transferring resin is usually critical and small size kinetic
advantage would not be justifiable. Small resin size can be a disadvantage
since they have found with dilute feed solutions that film diffusion, not
pore diffusion, controls.
The second question asked for comment on the apparent inter-
changeable use of the terms "attrition" and "loss of capacity" by the
authors, since the discusser has found attrition does not mean a marked
change of loss of capacity.
The third question asked was in regeneration of the resin with
strong acid and base, what is the possibility of permeation of the acid
and base to attack the iron core and break up the resin?
B.2 R. K. Chalmers (UK) described the process as "elegant" and felt
the process was "very clearly described," the investigation was "logical,
direct and conclusive," and this was "an advancement in knowledge." Figure
2 in the paper needed explanation. It did not seem to mention Na nor is
the link between that effect and elution of calcium ion with zinc sulfate
very apparent.
It was not clear what is done with the ZnSO^ used to elute the
adsorbed calcium from the resin. Did it come off within purity restric-
tion for calcium for reuse? If not, what happens to it and how much zinc
is lost in the treatment?
It was surprising to find worthwhile the recovery of 50 kg/day
of zinc for reuse water purposes while no mention was made by the authors
of recovery of more expensive metals such as cadmium, copper and nickel.
He asked the authors to comment.
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The discusser posed several questions:
1. Was there any danger of tracking liquid down the side of the
1.5 cm diameter column used in the initial studies?
2. What determined a diameter of 70 cm in the middle scale plant?
The lab was 1.5 cm, the middle scale 70 cm, and the full scale
15-20 times larger. The discusser's experience was that a final
scale-up of 100 times was justifiable.
3. What was the alkali consumption in raising the pH to 5-6? Was
there any precipitation in the effluent? Why was a settling
tank introduced in the full scale plant before the filter?
4. In the precipitation of CaS04 in pretreatment, is a supersatu-
rated solution of CaS04'2H20 left? Has there been any problem
with CaS04 precipitation in the ion exchange system? The dis-
cusser has experienced CaS04 resin column blockage.
5. Would the process be applicable to acid zinc solutions? Is
there any instance of chelation resins being effective for metal
cyanide complexes?
6. How often does the window in the color detection instrument need
to be cleaned? Wouldn't it be better to use atomic adsorption
or a limit test using dithiozone?
7. Is activated sludge applied to this waste alone or in combination
with other wastes? 95 percent removal is "remarkably good." It
would be desirable to know more details of activated sludge
process.
8. The process holds promise as applicable to other fields.
B.3 F. G. deWilde (South Africa) stated the work was done with "utmost
scientific care" and commented on the "clarity of writing." He was pleased
with the cooperation of the industrial group with a scientific institution.
In an earlier paper in 1973, costs were presented of 6£/m3 for
operation and resin replacement, and 8-10tf/m3 for total cost including
amortization and interest. What is the present cost?
The authors mentioned anionic detergents and organic acids
(1000-10,000 MW) as fouling agents. Dr. deWilde asked for examples of
the low molecular weight organic acids and bases that can be adsorbed
and regenerated and examples of the high molecular weight that would not
cause chain entanglement. He also asked for examples of industrial sites
where the authors planned to use the process.
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C. Floor Discussions
C.I Dr. Van Vhet (South Africa). In the pipeline process with waste-
water, it can be assumed that the suspended solids will be removed along
with the resin in the settling tank and both will be passed to the regener-
ation section. What happens to the suspended solids buildup over a long
period operation? If the rate step control is the external film, would
this be a partial explanation for the increased rate seen in practice against
the lab data?
Representative from Australia. The author mentioned cation resin
in the paper. Is anion resin made and is it commercially available. The
author reported resin capacity as 5 meq/g at about 50 percent iron or 10 meq/g
for pure material. Is this usually high capacity used for dealkalization?
Commercial resins will foul up from materials such as organics. Will the
magnet resin foul up when used with wastewater?
D. E. Weiss (Australia). The purpose of the work described in
the paper was to get a simple reliable technique for continuous operation
in large scale operation since most ion exchange processes are not truly
continuous. The design scale of operation is about 100 mgd plant size.
Since large scale systems use processes as settling and percolation through
sand, these processes are used as guides. The pipeline reactor has very
good control of contact time, turbulent flow, plug flow and a settling
device and is easy to scale to any size. The work done to date has been
a single stage system only. Future work will be on multi-stage units.
Reply - The magnetic resin can be made in a larger size and
therefore could be used in the multi-stage column. The increase in par-
ticle size will lose the advantage of kinetic rate but the advantage in
separation and transfer are still retained and possibly enhanced. This
is a problem in optimization.
The data indicate pore diffusion controls. However, independent
of whether film or pore diffusion, the rate would increase with decreasing
size but not as fast if it was film diffusion control.
There are two aspects of resin attrition - physical and chemical.
The pilot plant was operated for 2500 hours with wastewater with little
physical attrition. The changes, which were noticed, were due to a chemical
effect. The cause was due to acid hydrolysis since in the initial opera-
tion there was no regeneration pH control and very low pH levels did occur.
The experience indicates pH should not be lower than 2. If not, leaching
and corrosion of iron can occur and damage the resin. There is also a low
contact time in the regeneration of about one minute. Their operation at
one minute detention at a pH of 3-4 indicated no problems.
If the settling tank is at the end of the pipeline or fluidized
bed, a small amount of suspended solids will be captured and recycled to the
regeneration column. It was not found to be a severe problem in the pilot
plant work. If a magnetic separator is used instead of a settling tank,
there will be little trapping of solids. Studies showed 99-100 percent of
the influent turbidity out with the effluent.
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A weak base magnetic resin has been made but it is still in
the experimental stage. The weak acid resin has been used in a pilot
plant but the resin is not yet commercially available.
The magnetic resin has a capacity of 4-5 meq/£. Pure poly-
acrylic acid capacity would be 10 meq/£. The resin capacity is about
half. There were no adsorbed organics found on the resin and it appears
that little adsorption occurs in the work reported.
C.2 One of the two floor questions (Dr. Sashe, Japan) concerned
the effect of scale on overall selectivity. What type of factors did
reduce to uneven velocity or uneven depressions in resin surface or did
it come from size of operation? If not, could the authors identify any
distinct cause-effect resin shape between selectivity of zinc and uneven
adsorption that occurred. Possibly the adsorption may be the rate deter-
mining factor but the breakthrough characteristics may suggest a possible
depth and velocity effect on changing selectivity.
The second floor question (Australia) concerned two aspects.
The first aspect concerned the question on the molecular form of the
resin and what was the functional group. The second aspect concerned
the possible effect of volume change of the. resin on the breakage of
small lab columns (1:5 cm).
Reply - There was a misprint in Figure 2 in the original paper
where Na concentration should replace Ve/Vb. In this figure Zn and Ca
ions were studied separately. In full scale the total metal ion was only
0.3 kg/day lost outside. When calcium was eluted with ZnS04, about 2.5
kg/day of Zn will come out of the column. However, this soTution of Zn++
will be returned to the settling tank. The system was studied for zinc
because of a serious industrial waste problem involving zinc removal.
This system has been used in Japan for Ni from metal plating.
The author agreed with the discusser's comments on scale-up.
The plant scale-up was limited by capacity of filtration before chelating
resin treatment. The CaS04 was not precipitated in this treatment but
there was a possible CaS04 precipitation in elution process with ZnS04.
The problem was solved by an operating change of dilution of ZnS04 before
use.
The details of the activated sludge plant will be reported in
the future. It is now being studied in the lab. The only feed is from
the industrial waste treatment system reported here.
In responding to Dr. Sashe, the author stated that selectivity
is a function of the concentration of metal ion, calcium in solution and
the resin phase. This volume depends on activity of reaction phase, not
contact time. It did not reach equilibrium state. Because reaction between
resin and ion depends on adsorption, the apparent selectivity coefficient
is very high with space velocity.
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Responding to the discusser from Australia, the author commented
that the functional group is amino acid. It contains OH group in polymer
matrix and has hydrophylic properties. The base co-polymer is styrene-
divinyl benzene. Their UR-10 resin is very effective.
C.3 Cosgrove (World Bank). In developing countries many water sup-
plies are greater than the WHO level of 1500 mg/£ TDS. The present salt
removal process requires technology to operate. Would your system be
simpler to operate?
Stevenson. Could your process be used to remove nitrate in
simple small units?
Reply - The costs now are about 7$/m3 for a 10 mgd plant and
for a 0.1 mgd plant. The cost will also be a function of the salt
removed and the cost for heat. An advantage is that the heat is low grade
and can often come from industrial waste heat sources. In addition solar
heat could be applied.
Work on organic fouling has been done with sulfited alcohols
up to Cs-Cg which was no problem in regeneration. From Cg-Ci6» there
were some problems with branched chains but could still regenerate with
caustic brine. Proteins with molecular weight >15,000 were excluded.
Most common sources of fouling are the carboxylic acids, i.e., humic and
fulvic acids. Analysis of material stripped from organic fouled resin
showed carboxylic acids with MW range of 1000-10,000. These could be
removed with difficulty with caustic brine. These organics can be removed
with organic resin pretreatment to avoid resin fouling. They are working
on building a charge on the surface interface so larger molecular weight
compounds would not penetrate the Sirotherm resin.
The pilot plant in Japan has been moved to the Central Chemical
Research Lab to recycle laboratory wastewater. 03 is being used which
might change the organic fouling problem by breaking down carboxylic com-
pounds. Possible industry locations for the process under discussion in
Japan would be steel, coal and brewery.
The control conditions for the process do require fairly sophis-
ticated techniques. These are feed water pH and deoxygenation regeneration.
At present fixed beds give short cycles. They are looking at simpler
control procedures such as moving bed.
The resin will remove nitrate and there is some selectivity of
nitrate over chloride. With wastewater feed very low levels of ammonia
and nitrate were found in the effluent. At present it is still complex and
not suited for small scale.
IV. CRITIQUE OF SESSION
Paper No. 65 describes newly developing technology and appeared
to be somewhat original. The quality was very good.
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The presenter of Paper No. 68 had great difficulty speaking
English and, conversely, of being understood. The prepared discusser was
quite impressed with the paper. This had the most scientific detail of
the three papers in this session. Unfortunately, the author's difficulty
with English reduced his effectiveness. The work appears original and its
quality is very good. Only two people contributed to the floor discussion
indicating the audience was not overly familiar with the area under discussion.
There were only two floor discussions for Paper No. 71 and they
did not directly address the materials presented in the paper. A lack of
floor discussion might be attributed to the fact that this was the last
paper in the session and thus the Conference. Paper No. 71 mentions that
organic fouling is a major problem and the presenter of the paper gave
too little information even when asked directly on this subject. This
seemed to be part of a series of papers covering this process. Therefore,
it does not appear to be highly original; it is more like a progress report.
However, the quality was good.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
The results of Paper No. 65 apply directly to both water and
wastewater fields. Since the magnetic resin and pipeline reactor have only
advanced to the pilot plant stage, this concept should be reviewed to see
where its priority and application should be.
The metal industry would be very interested in Paper No. 68.
In addition, industrial wastes with metals are applicable. The concept
of creating a method to reuse and recycle industrial wastes is commendable.
With regard to Paper No. 71, there was a feature article in
Environmental Science and Technology in its October 1976 issue covering
ion exchange and included the Sirotherm Process for water as one of its
major subjects (page 980). For wastewater the area is still developing
and certainly could help solve U.S. water pollution problems in reuse.
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I. SESSION
A. Theme of Session: Fixed Film Biological Contactors
B. Papers Presented: 60. Theory and Design of High-Rate Media
Trickling Filters.
J. A. Oleszkiewicz (Poland)
63. Biological Rotating Disk Scale-up
Design: Dissolved Oxygen Effects.
W. H. Chesner, A. H. Molof (USA)
II. REVIEWER
A. Name: Calvin P. C. Poon
B. Position and Affiliation: Professor of Environmental Engineering
University of Rhode Island
Kingston, RI 02881
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 60
The paper presents the development of a model to describe the
performance of a high rate media trickling filter. The model is identi-
cal to a substrate removal model of the plug flow activated sludge if
the trickling filter biomass is related directly to the specific surface
area, i.e., activated sludge solids correspond to the specific surface
area in biofilters. Some limited amount of the author's data as well as
results from other workers are presented to verify the model. A general
guideline for the design of high rate media trickling filter is also
presented.
A.2 Paper No. 63
The author, in the paper presented, attempted to delineate a
problem in the biological rotating disk scale-up design concerning only
the dissolved oxygen transfer in the process. The data show a decrease
in peripheral velocity resulting in a reducing overall dissolved oxygen
concentration. However, peripheral velocity is related to disk diameter.
Rotational velocity, independent of disk size, correlates much better
with the reactor DO concentration than peripheral velocity. A model was
presented to relate the DO at the first stage with rotational velocity
and COD. The author, however, in his conclusion stated that rotational
velocity is impractical to use as a design scale-up speed. This is
mainly due to the fact that rotational velocity scale-up in a full-scale
plant may lead to excessive shear forces on the fixed slime and power
requirements. Peripheral velocity is still the design speed of choice
today.
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B. Prepared Discussions
B.I The discusser, J. Roberts (Australia), raised a question on the
author's interpretation of effluent changes in many diagrams presented in
the paper. When recirculation is involved in the operation, an interaction
of flow rate Q and feed concentration Sa on effluent Se is in effect. The
interpretation of the intercept to mean feed concentration would be
erroneous. The discusser presented a mechanistic model which includes
all parameters used by the author's model. In addition, the discusser's
model includes a recirculation concentration parameter as well as an
influent substrate inhibition function. More significantly, the model
has separated the process variables, flow rate Q and influent concentration
Sa from the plant or design variables, packing specific surface area, A,
and packed height, H. The given model and the diagrams presented show
clearly the advantage of the discusser's approach in that erroneous inter-
pretations can be eliminated.
B.2 Two prepared discussions were presented. G. Rincke of the
Federal Republic of Germany presented results which show an increasing
of peripheral speed of disk results in larger values of the oxygen trans-
fer coefficient, K|_a. Similar to the author's work, the results show that
smaller disks have higher oxygen transfer .capabilities for the same per-
ipheral speed. For a 3 m diameter disk turning at 15 rpm, the peripheral
speed is 2.4 m/sec which may, according to the discusser, have detrimental
effects on the slime layer due to the excessive shear force. N. W. Schmidtke
of Canada commented on the author's work with a suggestion that the value
of the paper can be greatly enhanced by stating more clearly the boundary
conditions under which the author conducts his work. The author should
study both the immersion depth as well as the wall effects. Although the
system cannot be properly described in terms of Reynolds, Froude, Weber
or power numbers, or even a combination of them, a calculation of the
Reynolds' number is useful. Hartmann in 1967 has shown that at a Reynolds'
number greater than 3 x 10^, the effect of turbulence on biological reaction
rate becomes negligible. The discusser also referred to his work on scale-
up methodology for surface aerated reactors involving a simple functional
power relationship between two independent variables of impeller diameter.
It was suggested to the author that the same scale-up function, but involv-
ing a different power exponent, could be developed for the rotating disk
system. Furthermore, the exponential value will indicate which forces
predominate in the system. Theoretically the exponent is near 0.5 when
gravitational forces predominate, 1.5 surface tension forces and at 2.0
viscous forces.
C. Floor Discussions
C.I Several comments were offered from the floor. These include:
1. The author neither considered nor included the flow regime
parameter in developing his model although the possibilities
of turbulent flow, quasi-trubulent flow, and rippled laminar
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flow have been mentioned. The possible incorporation of the
Reynolds' number in a model was suggested.
2. A model of the first order equation may overlook the possible
higher order and fractional order equations which could be more
suitable in describing the complicated unit process of a high
rate media trickling filter.
3. The thickness of the slime layer was not considered in the
model.
4. The explanation of an abrupt change in direction of a straight
line log Se vs. the reciprocal of volumetric load (1/2) was
given by the author as an indication of an effluent concentra-
tion below which removal processes were slower. The explana-
tion is not convincing.
It should be noted that neither the author nor the designated
substitute was oresent to present the paper and to make the concluding
discussion. A lively discussion of the subject inside and outside of
the meeting room was absent.
C.2 The following comments and discussions were initiated from the
floor:
1. A study in the Philippines indicates that the oxygen transfer
mechanism should be divided into two parts, one from the atmos-
phere to the slime layer or the part of the disk emerging from
the liquid, and the other from the atmosphere to the liquid
and then to the submerged slime layer. The two transfer mecha-
nisms are different. The second part is related to the Reynolds'
number. The black-box approach taken by the author without
considering the basic mechanism in mass transfer contributes
to one more equation among nearly one hundred others which are
presently available. The author's finding of poor COD removal
at 2 mg/-£ or lower concentrations of DO in the liquid was also
questioned by the discusser since there is evidence to show
consistently a high performance by rotating biological contac-
tors with 0.1 to 1 mg/£ DO concentration in the system.
2. The validity of scale-up based on dissolved oxygen is questioned
because recirculation is often practiced in rotating biological
contactor operation just as in the operation of trickling filters.
When recirculation is in effect, the combined influent flow has
a much higher DO concentration and a lower organic concentration
than the influent alone. The relationship of DO with the rota-
tional speed of the disk as well as the organic substrate con-
centration, as is expressed by the author's model, does not hold
any longer unless recirculation parameter is included in the
model. It has also been observed in pilot plant studies that
the rotating biological contactors perform as a combination of
biological film filter and a suspended growth reactor. The
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removal of organic substrate by the suspended biomass is sig-
nificant. It is suggested that separate considerations are given
in substrate removal by the slime layer and by the suspended
growth in order that the true mechanism and kinetics of removal
can be understood.
3. The author used single disks for his study. No scale-up
consideration is given to the effect of banks of disks on oxygen
transfer as compared to single disks.
IV. CRITIQUE OF SESSION
Since Paper No. 60 was not presented by the author, a disappoint-
ment could be felt among the participants in the meeting. Much of the
questioning directed at the author by the discussers went unanswered. Much
old data, either by the author's own work or by other workers, were pre-
sented in the paper. .The model and its discussion have been presented
elsewhere by the author as it was so stated in the paper. Symbols in many
equations presented have not been properly identified, leading to unneces-
sary guessing by the readers. The design guidelines are too general to
serve any useful purpose.
The author's model, originating from a basic substrate removal
kinetics equation, does not show any new concept or incorporate any new
parameter when compared with a multitude of equations long available for
design purposes in Europe as well as in the United States. A designer
needs to carry out extensive pilot scale tests to derive the removal rate
coefficient, k, under various operating conditions. Even so, the uncer-
tainty of uneven distribution of slime in the media, decrease of the
effective surface area, A, and uneven distribution of liquid over the
media surface could be critical in scale-up for which the author's paper
offers no help.
The discusser's model (Equation 19) incorporates the recircula-
tion flow concentration and an influent substrate function. Two areas of
improvement over the author's model can be recognized. Firstly, inter-
action of flow rate Q and feed concentration Sa can be handled properly
in preparing the performance prediction diagram. Secondly, the inhibition
function allows a correction of regression of substrate degradability when
the liquid is recirculated many times through the filter. Nevertheless,
much of the criticism on the author's model also applies to that of the
discusser. Most significantly missing from these two models are slime
thickness and biologically active surface area per unit filter volume.
Unfortunately the difficulty in measurement of these two parameters pro-
hibits their incorporation into the prediction or design models.
Much discussion took place in the meeting following the presenta-
tion of Paper No. 63. The first question on this research work is whether
scale-up based on dissolved oxygen has any practical value. A pilot plant
study at the University of Rhode Island has shown high DO in latter stages
of biological rotating disk systems in severe overloading (over supply of
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organic substrate) and no recirculation circumstances. When recircula-
tion applies, as it is a standard practice for trickling filter and
biological rotating disk operations, even the first stage has high DO
concentration in organic overloading situations.
The author recognized the importance of rotational velocity
as a scale-up design parameter but decided against its use because it is
impractical to use. Furthermore, two discussers adequately point out that
the oversimplified approach taken by the author overlooks many important
factors such as banks of disks vs. single disks, wall effects, disk sub-
mergence, flow regime criteria such as Reynolds' number, possible use of
a functional power relationship which enables a designer to recognize
the predominant force in the system among the gravitational, surface
tension, and viscous forces.
Both papers present an empirical approach in an attempt to
deal with complex problems. It is generally accepted that the complexity
of biological contactor (both fixed film and rotating disks) processes
are such that theoretical models have proved impractical for design pur-
poses. On the other hand, empirical models cannot be extrapolated beyond
the operating conditions and, to some degree, the media (type, configura-
tion, and method of packing) for which they were devised. A theoretical
model is circumscribed by assumptions under which it is expected to follow
observed behavior. In general many restrictive assumptions can only be
met in laboratory experiments specially designed for the purpose. Theo-
retical development proceeds by relaxing these restrictions in turn, to
obtain an understanding of the overall system through understanding the
individual processes of which it is comprised. The resultant understand-
ing of basic behavior aids the practitioner when troubleshooting, designing
or operating, particularly under conditions for which little or no previous
experience is available.
In contrast, an empirical model makes little pretense of repre-
senting individual phenomena, since its purpose is to relate operating
input and output variables to each other. Accumulated experience is cor-
related so that it is available, in reduced form, to the practitioner who
expects accuracy under the conditions for which the information was gathered
but who accepts risks outside these regions.
It follows that a theory must always be qualified by its simpli-
fying assumptions and that an empirical equation must likewise be qualified
by the conditions prevailing at the time the data were generated. It is
in this spirit that the quality of both papers should be judged.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
For the paper on the high rate media trickling filter, an
empirical model is offered. The practitioners can be benefitted by
applying the model to design. It is unfortunate that the conditions
under which the data were gathered are not specified. However, much
of the data presented in brief forms in the paper have been presented
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in greater detail elsewhere and such information can be obtained from
references cited by the author {Ganczarczyk, 1960; Bruce and Merkens, 1973;
Oleszkiewicz, 1974, 1975). Consequently design engineers in America can
find use of the model under certain circumstances.
Much of the problem of scale-up has not been solved. The per-
formance of a trickling filter is greatly dependent on the distribution
and thickness of the active biological film. The empirical models presently
available cannot relate the process variables, flow rate Q and influent
concentrate on Sa, to the distribution and characteristics of the biological
film. Research in this direction is needed.
The authors of the paper on rotating biological contactors did
not present a working model with peripheral speed, the paper does point
out the significance of taking into consideration the relative rotational
velocity differences in scale-up. Presently there is a great variety of
rotating contactors on the market with different physical and mechanical
features. Coupled with the fact that the system works as a combination
of a biological filter process and a suspended growth process, the diffi-
culty of scale-up is easily recognized. Recirculation of effluent in
controlling the thickness of biological film and in distributing the
active biological film more evenly throughout all stages of the process
is perhaps the most important feature of the process operation. Future
research work should be directed to include these considerations in either
the development of theoretical and empirical models for design or the
development of a scale-up procedure for the process.
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II,
SESSION
A. Theme of Session: Uptake, Exchange Kinetics, Transport
B. Papers Presented: 66. Uptake of Americium-241 by Algae and
Bacteria.
J. P. Giesy, Jr., D. Paine (USA)
69. Nutrient Exchange Kinetics in Water
Sediment Interface.
C. P. C. Poon (USA)
72. Mercury Transport Interacting with Bed
Sediment Movements.
A. Kudo, D. R. Townsend, D. R. Miller
(Canada)
REVIEWER
A. Name: John Cairns, Jr.
B. Position and Affiliation: University. Distinguished Professor
Virginia Polytechnic Institute and
State University
Blacksburg, VA 24061
III. REVIEW OF SESSION
A. Formal Papers
A.I Paper No. 66
The important feature of this paper is that it was concerned
with one of the most toxic substances known to mankind. Another inter-
esting point was the surprisingly similar results in uptake for both
pure cultures and aufwuchs communities.
A.2 Paper No. 69
The major point of this paper was that there was more phosphorus
coming out of the mud in very polluted areas than the inputs from all other
sources combined.
A.3 Paper No. 72
This paper presented a fairly detailed study of the mercury
distribution, transport and transfer (including seasonal effects in all
categories) in an aquatic ecosystem. Kudo feels he can estimate both
distribution and transport in rivers.
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B. Prepared Discussions
B.I J. Slade (UK) pointed out how unlikely it was to have in a single
institution both talent and facilities necessary to carry out such a study
(this suggests confirming data not likely to be generated).
B.2 W. Stumm (Switzerland). The most serious criticism was that
Poon paid no attention to the chemical characteristics of the interstitial
water. The second was that over time, sediments can be either a sink, or
a source of phosphorus, manganese, etc. and understanding which depends on
the redox potential.
B.3 T. Sueiski (Japan). Mostly complimentary review. Pointed out
that the paper only mentioned 75 samples while the research actually had
thousands.
C. Floor Discussions
C.I No significant floor discussion due probably to the almost total
ignorance of the audience of americium.
C.2 A substantitive comment by Home:
1. Is rate of sedimentation constant over geologic time?
2. Should Poon have used shock loads?
3. If the supply rate from sediments was greater than from sewage
and other sources this can only be a temporary situation.
Reply - This was only a limited simulation with a gross check
on the field situation and there was no attempt to study the mechanism of
tieup of nitrogen and phosphorus. Poon also assumed a constant rate of
sedimentation although he realized this was probably not actually true.
IV. CRITIQUE OF SESSION
The paper by Giesy (No. 66) may well be the most important of
the conference in terms of identifying a problem of major political and
social concern. The audience reaction was cautious as is typically the
case when a professional group is faced with an unexpected problem of
possible major significance. Giesy's research and presentation were
generally acclaimed despite the paucity of discussion. Poon and Kudo
gave good first approaches to systems dynamics problems.
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
Concerns identified by Giesy's paper deserve serious immediate
attention, i.e., how to cope with ultra toxic materials. It would be
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irresponsible not to get more information about the biological effects of
americium. The other papers provide useful information and examples of
how such monitoring can be carried out. They also identify pitfalls in
such studies.
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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 categor-
ized. The Chapter represents primarily a summary of Chapter II; however,
other observations made by individual participants regarding international
developments of potential interest to EPA, not emanating from the formal
program of the Conference, are indicated.
Developments at Formal Sessions
This section highlights the individual reports contained in
the previous Chapter by reviewing the more significant observations 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 work-
shop 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.
Virus and Pathogenic Organisms --
There was appreciable interest at the Conference in work pre-
viously reported in Science and elsewhere indicating a higher incidence
of enteric communicable diseases in kibbutzims in Israel which practice
spray irrigation of partially treated, non-disinfected oxidation pond
effluent as compared with kibbutzims practicing no form of wastewater
irrigation (Paper No. 1). Doubts were expressed (Workshop on Land
Treatment), however, about the application of the epidemiological results
to American practice because of the higher background level of enteric
disease in Israel, the greater degree of concentration of organisms in
wastewater, and the lower degree of treatment provided prior to spraying.
Additionally, a recent study of absentee records from employees of the
Werribee Farm (Melbourne's sewage farm) in Australia showed a lower rate
of absenteeism than for other employees of the same organization, the
Melbourne and Metropolitan Board of Works (Workshop on Land Treatment).
The need for collecting additional epidemiological data in the United
States on the incidence of infectious diseases among both waste treatment
plant personnel and residents in the immediate vicinity of wastewater
treatment plants was suggested (Paper No. 1).
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The unreliability of a bacterial virus as a model of the
behavior of an enteric virus was emphasized (Paper No. 7). Confusion
concerning reported information on virus movement in soil systems was
noted and research to clarify the matter was suggested (Workshop on
Land Treatment). Because of the resistance of certain enteric viruses
to environmental conditions and certain disinfectants, acid-fast
organisms (e.g., Mycobactvuum fioJituitum) and yeasts (e.g., Candida.
¥KUiapt>ito&
-------
Integrated Pollution Control Systems —
Conference participants were interested in a system for using
fly ash from air pollution control scrubbers for wastewater clarification
(Paper No. 28). Substantial savings in the cost of coagulating chemicals
was indicated, and data were presented indicating that the heavy metals
contained in the fly ash were not released to the wastewater. A need
was identified at the Conference (Paper Nos. 37, 40, 43, and 46) for more
effective integration of physicochemical wastewater treatment processes
with conventional (or novel) biological wastewater treatment techniques.
Opportunities for achieving higher degrees of treatment while avoiding
excessive expenditures were felt to be available.
Advanced Wastewater Treatment —
Advantages of surface aerated equalization ponds in reclamation
systems were emphasized (Paper No. 33). In addition to affecting equali-
zation of water quality, the ponds improved the efficiency of ammonia
stripping towers, reduced the degree of calcium carbonate supersaturation,
allowed for some destruction of pathogens, and facilitated breakpoint
chlorination.
Experiences in South Africa verifying the advantage of adding
lime in a recycling stream as compared to direct lime addition were
reported (Paper No. 37). The practice allows for crystal seeding and
increases reaction time.
An interesting report was presented on the use of magnetized
resin in a moving bed ion exchanger (Paper No. 65). A dramatic increase
in settling rate occurs upon magnetization. The process, currently
being developed in Australia, is in the pilot plant stage.
Ocean Pollution —
Based on British experience, one author concluded that primary
sedimentation prior to ocean disposal of effluent was not considered to
be justified (Paper No. 21). The environmental degradation associated
with sludge disposal from such facilities was felt to exceed the improve-
ment in ocean water quality. Primary treatment may be justified with
sewages of high grease content.
Land Treatment —
There was appreciable interest at the Conference in the
Werribee Farm Land Treatment System used by the City of Melbourne.
Raw sewage is applied by flood irrigation at a rate of about 105 cm/yr,
and the land is used for grazing by beef cattle and sheep. Beef carcasses
are inspected prior to sale, and no health problems have been identified
(Workshop on Land Treatment).
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Miscellaneous --
Lining of sewer pipes for corrosion control, using resin
impregnated terylene, was reported to be practiced in Singapore
(Paper No. 44). Five to 15 mm linings are produced which are rigid
and self supporting.
A novel means for the surface water quality modeling was
presented by a French researcher (Paper No. 8). A sophisticated
statistical transformation model is used to manage large water quality
data matrices.
A need was suggested for improved analytical techniques for
measurement of oils and greases (Paper No. 48). A need exists for
distinguishing between oils and greases of vegetables, animal, and
"mineral" origin.
Developments Outside of Formal Sessions
Much of the beneficial exchange of technical information
which occurs at professional meetings takes place outside of the formal
meeting rooms, and at international conferences the opportunities for
effective information transfer by this means are considerable. Partici-
pants in the development of this report were asked to submit comments
obtained from such interactions with water pollution researchers from
other nations. Several of the participants also submitted comments on
the value of the international exchanges on water pollution research.
These reactions and items of possible interest to EPA which were not a
part of the formal Conference program are summarized in this section.
Nature of the Conference --
One participant, a veteran of several IAWPR biennial conferences,
indicated a general improvement in the quality of papers presented at
Sydney. Another participant related a general feeling he perceived among
Conference participants that inadequate basic research in water quality
control is being performed globally.
One participant remarked that participation in the Conference
had been worthwhile if only because "it was most reassuring to verify
that my appraisal of the research progress of others in my field was
accurate." The same participant indicated that as a result of the
Conference, he felt that he would now have far better access to unpublished
data of foreign researchers. Perhaps the following statement best
summarizes the remarks made by many participants concerning the value
of exchange of technical information with water pollution researchers
in other nations:
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"In general, the research papers reflected the needs
of the respective nations conducting the research. For
example, water reuse was dominant in the contributions
from Israel and South Africa, while secondary and advanced
treatment reflected research in North America and Europe.
One value of this type of conference is that research
from one nation can be meaningfully discussed and con-
tributed to by researchers from other nations. This was
amply demonstrated in many of the sessions where the
experience from many nations in similar and allied areas
greatly enhanced the technical value of the primary paper.
To the writer's knowledge, this is the only forum in water
pollution research where this type of interaction is
achieved."
Health Related Research —
One participant expressed disappointment at the small number
of health-related papers on the technical program but felt that his
conviction that health effects is an area which deserves far more
attention of researchers in the United States was verified by the wide-
spread concern over health-related problems expressed in personal
conversations at the meeting. A startling claim of possible transfer
of antibiotic resistance from coliforms to pathogenic organisms was
related by a participant from New Zealand. He indicated that he had
observed such a transfer even between species, genera, and families.
It was suggested that several recent outbreaks of typhoid fever might
be attributed to this phenomenon.
A Brazilian researcher discussed the survival of enteric viruses
and coliforms in sediments around ocean outfalls. He noted that they
had much longer survival times in sediments than in overlying water and
indicated the possibility of resuspension of pathogenic microorganisms
and viruses.
Concern with the report (Paper No. 1) of epidemiological
evidence of aerosolization and dispersion of enteric microorganisms
during spray irrigation in Israel was not confined to the technical
sessions. One of the participants indicated a conversation with a
researcher from Israel in which it was indicated that the disease-
causing organisms could have been transported to the villages on the
clothing of field workers who were exposed to the sprayed effluents in
the fields or on the vehicles used on the fields.
Because of the location of the Conference, the Werribee Farm
near Melbourne which has been practicing waste application on land for
80 years was a frequent topic of discussion. One concern which came from
private conversations about the Werribee Farm was the transmission of
Taenia in the meat of these cattle. A significant point was the develop-
ment of a vaccine which can be injected into the animals to immunize them
against Taenia.
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Ocean Disposal —
Because of national differences in practices with regard to
wastewater and sludge disposal to the ocean, this topic was frequently
discussed in informal sessions, particularly the need for even primary
treatment of wastewater prior to ocean disposal. One participant reported
a general consensus, from informal discussions, of a lack of incentive
to remove nutrients prior to ocean disposal; but pretreatment for heavy
metal removal might be considered.
Scale of Facilities —
A participant reported on discussions indicating concern with
a tendency for increased regionalization in wastewater treatment. The
gist of the concern was that as the scale is increased, so are siting
problems and transportation costs; and the problem of disposing of sludge
and reusing effluent are magnified. When resource recovery from waste-
water is a societal goal, dispersal of treatment facilities may have some
merit.
Wastewater Reuse --
The following quote from a participant summarizes the general
thoughts on wastewater reuse by several participants:
"Wastewater reuse, rather than simply receiving
water quality control, appears to be more and more an
issue of global concern with respect to water pollution
research. Water shortage in many areas of the world,
coupled with increasingly stringent effluent quality
requirements, are bringing heretofore separated aspects
of wastewater treatment technology and water development
and treatment technology closer together. De facto
reuse exists; planned reuse is a near-term reality.
This will likely have profound effects on the philosophy -
and technology - of wastewater treatment."
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APPFNDICES
-------
Appendix I
CONFERENCE PROGRAMME
QUICK REFERENCE PROGRAMME OF ALL
ACTIVITIES
SATURDAY. OCTOBER 16
12 noon - 8 00 p m REGISTRATIONS - Wentworth
Hotel
SUNDAY.OCTOBER 17
900am -500pm
Morning
Afternoon 4 20 p m
Evening 6 30 p m
730pm
REGISTRATIONS -Wentworth
Hotel
EXCURSION E 1 -City sights
OPENING CEREMONY -
Sydney Opera House
OFFICIAL RECEPTION -
Sydney Opera House
CONCERT -Sydney Opera House
MONDAY, OCTOBER 18
Morning 900am FIRST TECHNICAL SESSION -
Wentworth Hotel
EXCURSION E 2 - Northern
Beaches
Afternoon 2 00 p m SECOND TECHNICAL SESSION
i - Wentworth Hotel
^ 430pm FIRST SHOWING -I AW P R
V film
EXCURSION E 3 - Wildlife Sane
Evening EXCURSION E 4 - Sunset and
Starlight
TUESDAY.OCTOBER 19
Morning 9 00 a m
9 15am
Afternoon 2 00 p m
Evening 6 30 p m
THIRD TECHNICAL SESSION -
Wentworth Hotel
HARBOUR CRUISE (For
Accompanying Persons)
FOURTH TECHNICAL SESSION
- Wentworth Hotel
AUSTRALIANA BARBECUE -
AJ C Randwick Racecourse
WEDNESDAY.OCTOBER 20
Morning 9 00 a m FIFTH TECHNICAL SESSION -
Wentworth Hotel
All Day EXCURSION E 5 - Blue Mountains
and Jenolan Caves
EXCURSION E 6 - Canberra
WEDNESDAY OCTOBER 20. Continued
Afternoon 2 00 p m SIXTH TECHNICAL SESSION -
Wentworth Hotel
430pm SECOND SHOWING-LAW P R
Film
EXCURSION E.7 -WildlifeSane
Evening Free
THURSDAY.OCTOBER 21
Morning 900am SEVENTH TECHNICAL SESSION
- Wentworth Hotel
930am VISIT TO ARGYLE CENTRE AND
PICNIC LUNCH (For Accompanying
Persons)
Afternoon 200pm FINAL TECHNICAL SESSION-
Wentworth Hotel
Evening 7 30 p m CONFERENCE BANQUET -
Wentworth Hotel
FRIDAY. OCTOBER 22
Morning 800am TECHNICAL INSPECTION TOUR
T 1 - Malabar and Southern
Beaches
800am TECHNICAL INSPECTION TOUR
T 2 - Shell Oil Co . Clyde
EXCURSION E 8 - Taronga Park
Zoo
All Day EXCURSION E 9 - Hunter Valley
Mid-day 1230pm FAREWELL HOUR-Wentworth
Hotel
Afternoon 130pm TECHNICAL INSPECTION TOUR
T 3 — Warnewood and Northern
Beaches
130pm TECHNICAL INSPECTION TOUR
T 4 - Castle Hill and Koala Park
SATURDAY, OCTOBER 23
Morning CONTINUING EDUCATION
COURSE Commences Melbourne
SUNDAY, OCTOBER 24
INTERNATIONAL
CONFERENCE
PROGRAMME OF
TECHNICAL & SCIENTIFIC
SESSIONS & WORKSHOPS
Conducted at the
WENTWORTH HOTEL
Monday October 18 until
Thursday October 21
ENQUIRIES CONCERNING ALL ASPECTS OF THE
TECHNICAL & SCIENTIFIC PROGRAMME SHOULD
BE REFERRED TO MR. R. R. ASH AT THE TECH-
NICAL SESSIONS OFFICE, MEZANNINE FLOOR,
WENTWORTH HOTEL.
Morning
POST-CONFERENCE TECHNICAL
INSPECTION TOUR COMMENCES
-------
GENERAL ARRANGEMENTS
All sessions and workshops will be held in the Conference
meeting rooms. Mezzanine Floor, Wentworth Hotel, from
Monday October 18 to Thursday October 21. inclusive
The conduct of the sessions will be as follows
1. GENERAL ARRANGEMENTS
1 1 All Conference sessions on Monday 18 to
Thursday October 21 will be at the Wentworth
Hotel, Sydney, commencing at 9 a m and at
2pm
Three Halls, A, 8 and C will be in use concur-
rently except for the Workshops on Tuesday
and Thursday when only two Halls, A and B,
will be in use.
Simultaneous interpretation will be operating
in English, French and German in Halls A and
B Sessions in Hall C will be conducted in English
1 2
1 3
,
V3 2. CONDUCT OF SESSIONS (OTHER THAN
"f WORKSHOPS)
21 Each of these sessions will be of 45 minutes
duration
2 2 The paper will be circulated in advance and be
taken as read Authors will be allowed ten
minutes to introduce the paper
2.3 The Chairman will call the nominated discusser
who will be allowed five m mutes to introduce
the discussion
2 A The Chairman will then call discussers from the
floor calling first those who have notified their
intention to speak by completing a discussion
slip No discussor will be entitled to speak for
more than three minutes save at the discretion
of trie Chairman.
25 No later than five minutes before the end of the
session the Chairman will close the discussion to
give the Author or Authors opportunity to reply
to the discussion.
CONDUCT OF
SESSIONS & WORKSHOPS
2 6 Nominated discussers and all subsequent dis-
cussors must confine their remarks to the sub-
ject of the paper, the Chairman has power to
halt discussion which goes beyond the confines
of the subject
3. CONDUCT OF WORKSHOPS
3 1 Each Workshop will be of 90 minutes duration
3 2 The objects of the workshops are to promote
informal discussion on subjects (as per the
Programme) of current interest, to identify
topics for further discussion or investigation
and to prepare a report to be included in the
Conference Proceedings
The Conveners have been responsible for nomi-
nating speakers who will introduce the discussion
No papers will be circulated m advance
3 3 The Convener will open the workshop promptly
and will take no more than five minutes to
introduce the general theme of the workshop
3.4 The Convener will then call upon the nominated
speakers in turn to make their points The
Convener will allow a total of 30 to 40 minutes
for this part of the workshop, allocating time
per speaker, accordingly
3 5 The Convener will then call discussers from the
floor giving priority to those who have notified
their intention to speak by completing and hand-
ing in a discussion slip No discussor will be en-
titled to speak for more than three minutes
save at the discretion of the Chairman.
3 6 The discussion will be terminated fifteen minutes
before the end of the session to enable the nom-
inated speakers to reply to the discussion and
the Convener to summarise the conclusions of
the workshop
4. PROCEEDINGS
No verbatim record will be made of the proceedings.
Contributors to the proceedings who wish their contribu-
tions to be recorded must send three copies in typescript
in English to the Secretary-Treasurer, IAWPR, Chichester
House, 278 High Holborn, London WC1, U K., to reach
him not later than November 30, 1976 The Editor re-
serves the right to accept, reject or edit these contribu-
tions for publication in the Conference Proceedings to
be printed in "Progress in Water Technology"
PRE-PRINTS OF PAPERS
Registrants who did not request that their copy of
the Pre-prints be sent to them prior to the Conference
can take delivery of their copy at the TECHNICAL
SESSIONS PROGRAMME OFFICE, each day of the
Conference between 8 30 a.m and 5pm
-------
MONDAY MORNING
HALL A
HALLB
HALLC
1. Spray Irrigation with Waste water: The Problem
of Aerosolization and Dispersion of Enteric
Microorganisms.
E. Katzenelson. B. Teltch. H.I Shuval (Israel)
9.00- Chairman B Hanes (USA)
9.45a.m. Recorder RA Canham (USA)
Discusser C Lue-Hmg (USA)
2. Great Lakes Water Quality Agreement.
James P. Bruce. Peter M. Higgins (Canada)
Chairman A Hanson (Sweden)
Recorder B Rosen (Sweden)
Discussor KW Lewis (Australia)
3. Comparative Evaluation of Commercial Polyelectrolytes
for Flocculating Alum Precipitated Domestic
Waitewater.
Andrew Benedek. John L. Bancsi (Canada)
Chairman P Benedek (Hungary)
Recorder C.P Fisher (Canada)
Discussor H.N S Wiechers (South Africa)
4. Virus Retention by Soil.
K.V. Abdulla Koya. Malay Chaudhuri (India)
9.50- Discussor HI Shuval (Israel)
10.35a.m.
5. Localised Destratification of Large Reservoirs to
Control Discharge Temperatures.
Frank L. Burns (AustialU)
Discussor L H James (S Africa)
6. Treatment of Chlorinated Hydrocarbons Wastewater by
Activated Carbon Absorption with Steam Regeneration.
Yerachmiel Argaman. Giovanni M. Sassu (Israel)
Discussor F Middleton (USA)
Ai 7. The Removal of Viruses by Slow Sand
jo Filtration.
i S.F.B. Poynter. J.S. Slade (Great Britain)
11.00- Chairman H McFie (Australia)
11.45a.m. Recorder LF Scragg (Australia)
Discussor L Com (France)
8 A Multidimensional Analysis of the Results of the
French 1971 Surface Water Quality Network Control
in the River Basin "Seine-Normandie".
Y. Le Foil. R. Pmoit. A. Lesouef (France)
Chairman G D M Roberts (UK)
Recorder J Garland (UK)
Discussor J J.Wright (Australia)
9. A Fundamental Study of the Removal of Polynuclear
Aromatic Hydrocarbons from Water During Chlonna-
tion.
Roger Perry. R.M. Harrison (Great Britain)
Chairman- D E Weiss (Australia)
Recorder N Norman (Australia)
Discussor- T E Larson (USA)
11.SO-
12.35 p.m.
10. Virus Removal m Activated-Sludge Sewage
Treatment.
V. Chalapati Rao. S.B. Lakhe. S.V. Waghmare.
Pushpa Dube (India)
Discussor. J F Malma (USA)
11. Hydrodynamics of Bubble Plumes and
Oxygen Absorption in Stratified
Impoundments.
F. Rayyan (Saudi Arabia). R.E. Speece (USA)
Discussor P A Krenkel (USA)
12. Chromium Removal with Activated Carbon
Jung I. Kim. John Zoltek. Jr. (USA)
Discussor B M Van Vhet (South Africa)
NOTES
-------
MONDAY AFTERNOON
HALL A
HALLB
HALLC
13. Nitrogen, Phosphate and Virus Removal from
Sewage Water During Land Filtration.
J. Clarence Lance, Chute* P. Gerba (USA)
2.00 - Chairman- W. Gujer (Switzerland)
2.45p.m. Recorder H I. Shuval (Israel)
Discusser. C. Lue-Hing (USA)
14. Technical Requirement! and Analysii Methods
for Evaluating the Environmental Consequence]
ol Ground water Contamination.
R.William Nelson (USA)
Chairman C. Basalo (Fiance)
Recorder C Cornelia (France)
Discusser B. Rognerud (Norway)
15. Sedimentation of Dispersed Oil in Surface Waters
M. Thuer. Werner Stumm (Switzerland)
Chairman A.L Downing (UK)
Recorder R Perry < UK I
Discusser To be Announced
16. Faecal Col if or ms and Faecal Streptococci:
A Statistical Comparison using Data from
England and Papua New Guinea.
R. Feachem. K. Khan. E. Rosebergen (Grt. Brit.)
2.50- Discussor. DJ Lane (Australia)
3.35p.m.
17. Pilot Plant Investigation of the Evolution of
Various Pollutant! During Artificial Recharge
of an Aquifer by a Basin.
Michele Rizet. Joel Malleviale.
Jean-Claude Cournarie (France)
Discussor BJ Lyons (Australia)
18. The Application of a Two-layer Time-Dependent
Model to Pollution Assessment and Control in a Short
Stratified.Estuary.
R.M. Pitblado, R.G.H. Prince (Australia,
Discussor B M Mollowney (UK)
Presented by G E Eden (UK)
us
en
19. The Effect of Ozone Bubbles on Disinfection.
Shaukat Farooq. Richard S. Engelbrecht.
Edward S.K. Chian (USA)
3.50 - Discussor W Stumm (Switzerland)
4JSp.m.
20. Hydrodiemical Effects of Waste Percolation on
Groundwater in Basalt near Footseray, Victoria,
Austral!*.
Mirko Riha (Australia)
Discussor M R. Henzen (S, Africa)
21. Preliminary Design of Ocean Outfall at Sydney:
Protection of Bathing Waters
I.G.Wallis. TJ. Pollock. MAW.Whyte (Australia)
Discussor. D Munro (UK)
Presented by G E Eden (UK)
NOTES
-------
TUESDAY MORNING
HALL A
HALLB
HALLC
Workshop — Current and Future Marina
Pollution Problem
Convenor: E.A. Pearson
9.00 - Recorder To be announced
10.35a.m. Speakers:
1 JD Isaacs
-------
TUESDAY AFTERNOON
HAL LA
HALLB
HALLC
28. An Integrated Pollution Control System:
Combined Clarification of Wasteweter and
Incinerator Scrubber Effluent and Utilization of
Clarified Effluent for Scrubbing of Stack
Emissions.
W J. Weber, Jr., F.L. Snitz (USA)
M. Rebhun (Israel)
2.00- Chairman D Stephen (USA)
2.45p.m. Recorder-P. Balmer(Norwav)
Discusser J. Barnard (S Africa)
29. Studios on Pyrolysb Process of Sewage Sludge
T. Majima. K. Tadao. M. Naruse. M. Hiraoka
(Japan)
Chairman S Iwai (Japan)
Recorder T Sueishi (Japan)
Discusser B M Ellis (Canada)
30. Comprehensive Temperature Model for Aerated
Biological Systems
Yerachmiel Argaman. Carl E. Adami, Jr. (USA)
Chairman R L. Earls (N. Zealand)
Recorder-D Bracken (N Zealand)
Discusser J Hollo (Hungary)
2.50-
3.35 p.m.
31. Design Approach for Effluent Variability
Removal in Wastewater Treatment Systems
Vladimir Novotny (USA)
Discusser B.B. Berger (USA)
32. Combined Disposal of Sewage Sludge and
Solid Wastes by the Pyrolytic Process
N.Brovko. R.A. Lockwood. R.R. Bowerman.
K.Y. Chen (USA)
Discusser B Lynam (USA)
33. The Efficacy of an Equalization Pond in a Water
Reclamation System
Ben M. Van Vliet, Herman N.S. Wiechers.
Oliver O. Hart (South Africa)
Discusser P Benedek (Hungary)
1 34. The Integration of Wastewater Treatment with
Water Reclamation.
Lucas RJ. Van Vuuren. William R. Rots.
Jan Prinsloo (South Africa)
3.50- Discusser JJ Wright (Australia)
4.35 p.m.
35. Disposal of Sludge Using Solid Wastes as Fuel
with Resource Recovery and Creation of Gas
End-Product for Utility Use.
Ivan L. Bogert. Daniel S. Greene (USA)
Discusser M Hiraoka (Japan)
36. Scale-up Methodology for Surface Aerated Reactors
NorbertW.Schmidtke (Canada).
Imre Horvath (Hungary)
Discusser FF KolbefS Africa)
NOTES
-------
WEDNESDAY MORNING
HALL A
HALLB
HALLC
37. Investigations into the Lime Precipitation of
Raw Municipal Wastewater.
David Jenkins. P.M. Lee (USA)
9.00 - Chairman E Kunlze (Fed Rep Germany)
9.45a.m. Recorder K R Imhoff (Fed Rep Germany)
Discusser LRJ VanVuuren(S Africa)
38. Simulation of Design-Storms with Probable
Distributions in Time and Space for Storm
Drainage Systems.
F. Sieker (Germany)
Chairman J Hollo (Hungary)
Recorder P Benedek (Hungary)
Discusser T Sueishi (Japan)
39. Fellmongery Waste Treatment — Comparison of Cost
and Degree of Treatment.
Henryk Melcer. Paul N. McFariane (New Zealand)
Chairman J D Salloum (Canada)
Recorder T. Davey (Canada)
Discussor JL Pretonus (S Africa)
40 Calcium Carbonate and Magnesium Hydroxide
Solubility Product Values for Heterogenous
Systems.
Herman N.S. Wiechers (South Africa)
9.50 - Discussor J Parker (Australia)
10JS a.m.
41. The Significance of Stormwater Runoff in an
Urbanizing Watershed.
Clifford W. Randall. John A. Garland.
Thomas J. Grizzard. Robert C. Hoehn (USA)
Discussor F S Vivier (S Africa)
42. Treatment Alternatives for Wastewater: from the Tapioca
Starch Industry.
Mainwaring B. Pescod. Ngyuen Cong Thanh (Thailand)
Discussor. A.D Carr (S Africa)
I 43 Advanced Wastewater Treatment by Chemical
' Precipitation with Lime and Ammonia Stripping
in Ponds.
Emanuel Idelovitch. Thea Roth. Medy Michail
(Israel)
11.00- Chairman H Caspars (Fed Rep Germany)
11.45a.m. Recorder G Rincke (Fed Rep Germany)
Discussor A Wachs (Israel)
44. Prevention and Protection of Sewerage Systems
Against Sulphide Attack with Reference to
Experience in Singapore.
A. Nadarajah. J. Richardson (Singapore)
Chairman LRJ van Vuuren (S Africa)
Recorder H C Stegmann (S Africa)
Discussor. E J Hall (S Africa)
45. Process Design Investigations for Alaska Pulp Mill
Wastewater Treatment Facilities
Howard Edde. Richard French. Oren Mason.
Toshi Hosoi (USA)
Chairman C J Price (Australia)
Recorder- R C. Williams (Australia)
Discussor FG Neytzell-de Wilde (South Africa)
46. Improvament of Tertiary Filtration Efficiency by
Upgrading Biological Activity.
G.M. Faup. J.L. Bebin. J.C. dacquart (France)
11.50 - Discussor W W. Eckenfelder (USA)
4.35 p.m
47. The Forecasting of Sulphide Build-up Rates in
Sewers.
Richard D. Pomeroy. John D. Parfchurst (USA)
Discussor G E Eden (UK)
48. Measurement and Treatment of Oil and Grease in
Petroleum and Petrochemical Industrial Wastewaters.
Lial F. Tischler. Richard L. Elton III
Davis L. Ford (USA)
Discussor B Audouze (France)
NOTES
-------
WEDNESDAY AFTERNOON
HALL A
HALLB
HALLC
49. Reeirculation Ponds - Pilot Plant and Field
Studies.
Gedaliah Shelef. Moshe Ronen. Moshe Kremer
(Israel)
2.00- Chairman-L Coin (France)
2.45p.m. Recorder MA Baud (France)
Discusser J Barnard (S Africa)
50. Currant Statui of Research in Automation of
Wastewater Treatment in the United States
Joseph F. Roesler. Dolloff. F. Bishop.
IrwinJ. Kugelman (USA)
Chairman W von der Emde (Austria)
Recorder C.Adams (USA)
Discusser W von der Emde (Austria)
51. Pollution Control Regulations and Monitoring
Technology: A Review of Research and Development
from the Pulp and Paper Industry
Derek V. Ellis (Canada)
Chairman-G Shelef (Israel)
Recorder To be Announced
Discusser B Hawerman and S Freyschuss (Sweden)
52. Seepage from Oxidation Ponds
Emanuel Ideloviteh (Israel)
2.SO - Discusser J Barnard (S Africa)
3.35 p.m.
53. A comparison of Pure Oxygen and Diffused
Air Digestion of Waste Activated Sludge.
David B. Cohen (Canada)
Discusser WW Eckenfelder (USA)
54. Biomonitoring with Fish: An Aid to Industrial
Effluent and Surface Water Quality Control
William S.G. Morgan (South Africa)
Discusser: J. Cairns (USA)
55. An integrated High Rate Pond-Algae Harvesting
System.
Joseph C. Dodd. John L. Anderson (Australia)
o
o
'3.50- Discusser W J Oswald (USA)
4.35 p.m.
56. The Dynamic Behaviour of an Anaerobic
Digester.
A.D. Carr. R.C. O'Donnell (South Africa)
Discusser H Schoenfelder (Fed Rep Germany)
57. The Use of Ozone Induced Chemiluminescence in Water
Quality Monitoring
V.A. Garten. R.B. Head. R. McNeil).
J.M. Overbeek (Australia)
Discusser C Gomella (France)
NOTES
-------
THURSDAY MORNING
HALL A
HALLB
HALLC
Workshop -Water Resources Quality Management
Convenor: W.K.Lewis
9.00- Recorder. DJ Lane (Australia)
10.35a.m. Speakers
1 PM Higgins (Canada)
Lakes and Impoundements
2 L B Wood (UK)
Rivers and Estuaries
3 H Schmidt (Fed. Rep Germany)
Underground Water
4 M R Henzen (S A )
Acid Mine Drainage
i
ro
58. Development of a Rapid Fish Toxicity Test
Utilizing a Freeze Concentration Technique
for Routine Petroleum Refinery Wastewater
Monitoring
E.G. Birchard (Canada)
11.00- Chairman MR Henzen (S Africa)
11.45air. Recorder P E Odendaal (S. Africa)
Discusser J Cairns (USA)
Workshop - Land Treatment
Convenor: A. Waehs
Recorder B Lynam (USA)
Speakers
1 C.E Pound (USA)
a) Rational basis for design of land d isposal systems
b) Long-term effects of infiltration of Wastewater
into soils
2 I P Hyman
Land disposal of intractable effluents
3 A Cotteme
Storage Capacity of SoSIs for Wastes of bio
industrial farming
4 JB McPherson (Australia)
Effluent Irrigation for fodder production
The basic concepts of 'land and grass filtration'
of effluents
59. Removal of Organic: in Sewage and Secondary
Effluent by Reverse Osmosis
Edward S.K. Chian. Sheng S. Chenq.
FoppeB Dewalle.
Powell P.K. Kud (USA)
Chairman B B. Berger (USA)
Recorder D Stephan (USA)
Discussor MA Baud I France)
60. Theory and Design of High-Rate
Media Trickling Filters
Jan A. Oleszkiewicz (Poland)
Chairman H. Jones (Australia)
Recorder N Klamus (Australia)
Discussor J Roberts (Australia)
61. Compounds Toxic to Fish in Pulp Mill
Waste Streams.
J.M. Leach. A.N. Ttiakore (Canada)
11.50- Discussor WSG Morgan (S Africa)
12.35p.m.
62. Series Intermittent Sand Filtration to Upgrade
Wastewater Lagoon Effluent
David W. Hill. James H. Reynolds. Steve E. Harris.
D.S. Fihp. E J. Middtebrooks (USA)
Discussor G Shelef (Israel)
63. Biological Rotating Disk Scale-up Design: Dissolved
Oxygen Effects
W.H. Chesner. A.H. Molof (USA)
Discussor G Rincke (Fed Rep. Germany)
NOTES
-------
THURSDAY AFTERNOON
HALL A
HALL B
HALLC
54. Nitrification in Free-Flowing Streami
Fernando F. Lopez-Bemal. Peter A. Krenkel.
Richard J. Ruane (USA)
2.00 - Chairman A Van Haute (Belgium)
2.45 p.m.. Recorder J Bebin (France!
Discusser-J Garland (UK.)
65. Ion Exchange in a Moving Bed of Magnetized
Reiin.
B.A. Bolto. D.R. Dixon. A J. Priestley
E A. Swmton (Australia)
Chairman T Tsutsui (Japan)
Recorder. M Hiraoka (Japan)
Discussor A D Carr (S Africa)
66. Uptake of Americium-241 by Algae and
Bacteria.
John P. Gieiy. Jr., Donald Paine (USA)
Chairman PA Krenkel (USA)
Recorder A Sato (Japan)
Discussor J Slade (UK)
67. Consideration of the Efficiency of Attached
Organisms in the Simulation of Self-Purification
and Oxygenation Capacity of Flowing Waters.
Peter Wolf (Germany)
2.50- Discussor. K Poppinghaus (Fed Rep. Germany)
3.35 p.m.
68. Recovery of Zinc using Chelating Resin
Hiroyuki Uejima. Masahtde Hirai.
Tadaya Ishibashi (Japan)
Discussor R K Chalmers (UK)
69. Nutrient Exchange Kinetics in Water
Sediment Interface.
Calvin P.C. Poon (USA)
Discussor W. Stumm (Switzerland)
ro
i
70. Comparison of Semi-Continuous and Continuous
Flow Bioassays
James H. Reynolds. E J. Middlebrooks.
D.B. Poredla. WJ. Grenney (USA)
3.50- Discussor. D Brocket! (N. Zealand)
4.35 p.m.
71. Water Demmeralization by a Thermally
Regenerable Ion Exchange.
B.A. Bolto. N.H. Pilkington. PJW. Sharpies.
G.K. Stephens. K.O. Wade. D.E. Weiss (Australia)
Discussor F.G Neytzell-deWilde (South Africa)
72. Mercury Transport Interacting with Bed Sediment
Movements
Akira Kudo. D. Ron Townsend.
Donald R. Miller (Canada)
Discussor T. Sueishi, T Morioka (Japan)
NOTES
-------
Appendix II
ASSIGNMENTS
Participants in USANC Report on Developments
at IAWPR Sydney Conference
SESSION
A-l
(Hall A, 9-10:35 am
A- 2
(Hall A, 11-12:35 pm
A- 3
(Hall A, 2-4:35 pm
B-l
(Hall B, 9-10:35 am
B-2
(Hall B, 11-12:35 pm
B-3
(Hall B, 2-4:35 pm
C-l
(Hall C, 9-10:35 am
C-2
(Hall C, 11-12:35 pm
C-3
(Hall C, 2-4:35 pm
18th
Monday
Farooq
Malina
*
Novotny
I
Larson
*
Giesy
i
Speece
19th
Tuesday
Pearson
„ . *
Cairns
Reynolds
Ford
*
Baumann
Zoltek
X
Lynam
Chi an
20th
Wednesday
*
Weber
V
Lockwood
Bogert
V
Eckenf elder
*
Adams
1
Edde
21st
Thursday
Canham
Pomeroy
Hanes
Lance
*
Baumann
Molof
X
Poon
Cairns
2 Sessions
-203-
-------
UNITED STATES OF AMERICA NATIONAL COMMITTEE
For representation of the United States to the
INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH
Chairman
OR RICHARD I DICK (A E E P I
Department of Civil Engineering
Urweriily of Delaware
Nmnvk. Oelnnn 19711
(302) 738 2431
Vo-Oicimun
OR OAVID G STEPHAN IA I Ch E I
Office ol Reuarch and Development
Environmental Protection Agency
Washington. 0 C 20460
12021 7554474
DR RICHARDS ENGELBRECHT (w P C f I
Dapennwm ol Civil Engineering
Umverniv of Illmoii at Urbana Champaign
Urbana. Illinoii 61801
(2171 333-3822
September 29, 1976
MEMORANDUM
TO:
FROM:
SUBJECT:
Richard I. Dick, Chairman
Assignments for Development of USANC Report
on Sydney Conference
The Coordinating Subcommittee for preparing USANC's analysis of develop-
ments at the IAWPR Conference at Sydney has met to determine the sessions to
be covered by participants in the project. Your assignment is to prepare a
penetrating analysis of developments at the following session:
Date:
Hall:
Time:
The Committee apologizes that the expressed preferences of all participants
for particular sessions could not be accommodated.
As soon as you recover from your travel to Sydney, it is essential that
you contact one of the members of the USANC Coordinating Subcommittee for the
SPONSORING ORGANIZATIONS
ASSOCIATION OF ENVIRONMENTAL ENGINEERING PROFESSORS AMERICAN CHEMICAL SOCIETY
VIERICAN INSTITUTE OF CHEMICAL ENGINEERS AMERICAN SOCIETY OF CIVIL ENGINEERS
WATER POLLUTION CONTROL FEDERATION
October 17-22, 1976
-204-
-------
Assignments for Development of
USANC Report on Sydney Conference Page Two
From; R. I. Dick September 29, 1976
EPA Report. The members are:
Bernard Berger
Richard Dick
Richard Engelbrecht
David Stephan
The purpose of contacting them is: (1) to verify your presence in Sydney,
and (2) to obtain detailed instructions for preparing your section of USANC*'s
report.
The Subcommittee appeals for your understanding because the new form of
the EPA grant and the late award of the grant require development of new
procedures under tight time constraints. The Subcommittee ±s still working on
the guidelines for report preparation which will be distributed in Sydney, but
you can anticipate the following major items:
(1) Penetrating Analyses! - If EPA desired a totally
objective and passive assessment of developments at
the Conference, they would buy the Conference
Proceedings for far less than they are paying us!
Interpretation of the significance of developments
and inclusion of insights gained outside of the
formal meeting rooms is essential.
(.2) Timely Submission! - A tight deadline for report
submission (probably November 22) will be imposed.
The value of our report to EPA diminishes rapidly
with time.
(31 Follow the Directions! - We'll be supplying some
guidelines on format—please help the Subcommittee
by following them.
(4) No Performance, No Money! - USANC's proposal to
EPA indicated that we would reimburse only those
participants who submit an acceptable report on time,
(5) Have Fun! - While some rigorous guidelines must be
imposed, they are not incompatible with the normal
objectives of attendance at a research conference.
I look forward to seeing you in Sydney.
ks
-205-
-------
Appendix IV
GUIDELINES
on
PREPARATION OF INDIVIDUAL REPORTS
on
DEVELOPMENTS AT THE EIGHTH INTERNATIONAL CONFERENCE
ON WATER POLLUTION RESEARCH, SYDNEY
October 17-23, 1976
Emphasis of Report
USANC's report to EPA on developments at the IAWPR Conference in Sydney
is not intended to be simply a record of the Conference. Instead, an inter-
pretive 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 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 American 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
United States.
Distribution
The report will be distributed at least within EPA, to USANC Sponsoring
Organizations and USANC committee members, and to participants in the report
development. Bylines will be included to acknowledge the authorship of
of individual sessions.
-206-
-------
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
time to each paper. Space in the report should be allocated on the basis of
relevance to American water pollution control problems and water pollution
research activities. It is anticipated that the average length of individual
session 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.
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 assigned session 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.
Submission
Individual reports are to be submitted in double-spaced typed finished
form. Reports are to be submitted by November 22, 1976 to:
Richard I. Dick
Department of Civil Engineering
University of Delaware
Newark, Delaware 19711
-207-
-------
Compensation
Compensation will be on the basis of statements for services and expenses.
As indicated in earlier correspondence, no reimbursement for international travel
can be allowed, and a maximum level of reimbursement based on available funds,
cost sharing requirements (grant based on 70% cost sharing), and the demands on
available funds will be established. Reimbursement will be dependent upon
receipt of an acceptable report prior to the deadline. 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 individual may hold up all payments). Requests for reimbursement are to be
sent to the USANC Secretary-Treasurer, R. S. Engelbrecht, at the same time the
report is submitted, use the expense voucher included as Attachment III for this
purpose.
Coordinating Subcommittee
Development of these guidelines, review and acceptance of individual reports
and preparation of the final EPA report is being coordinated by a U. S. A. National
Committee Coordinating Subcommittee consisting of:
Bernard Berger
Water Resources Research Center
University of Massachusetts
Amherst, Massachusetts 01002
Phone: (413)545-2842
Richard Dick
Department of Civil Engineering
University of Delaware
Newark, Delaware 19711
Phone: (302)738-2431
Richard Engelbrecht
Department of Civil Engineering
University of Illinois
Urbana, ILlinois 61801
Phone: (217)333-3822
David Stephan
Industrial Environmental Research Lab
Environmental Protection Agency
Cincinnati, Ohio 45268
Phone: (513)684-4439
Additional information concerning this USANC activity may be obtained from any
of the Subcommittee members.
-208-
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OUTLINE FOR INDIVIDUAL REPORTS ON
DEVELOPMENTS AT SYDNEY IAWPR CONFERENCE
*
I. SESSION
A. Day, Hall, Time
*
B. Theme of Session (a few words describing the major orienta-
tion of papers—e.g., "Marine Disposal" or
"Sludge Thickening and Dewatering")
II. REVIEWER
*
A. Name
*
B. Position and Affiliation
*
III. REVIEW OF SESSION
*
A. Formal Papers
B. Prepared Discussions
*
C. Floor Discussions
*
D. Other Observations and Comments Regarding Papers (Insights
developed outside of the meeting room,
possible sources of additional information,
etc.)
IV. CRITIQUE OF SESSION (Critically review the items in III, indicating
matters such as how the research reports were
received, their originality and quality)
*
V. SIGNIFICANCE AND VALUE TO AMERICAN WATER POLLUTION RESEARCH ACTIVITIES
(How might the reported results be applied to
solve U. S. water pollution control problems?
What research pertinent to U. S. needs is
suggested by the reported research?)
*
VI. INFORMATION AND OBSERVATIONS FROM THE CONFERENCE RELEVANT TO WATER
POLLUTION RESEARCH BUT UNRELATED TO ASSIGNED SESSION (Pertinent
information on global water pollution control
research which was not presented at any of
the formal sessions at the Conference.)
(Section VI will be separated from the remainder
of the individual reports—place on a separate
sheet which includes your name.)
it
These headings are to be contained in each report
-209-
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ATTACHMENT II
SCRIPT REQUIREMENTS
1. 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. Half-tone 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 printed and the other without inscription. If line drawings are already well
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 "dyeline"
prints or from prints with weak lines, and illustrations for reproduction should normally be about twice 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-offset means directly from the authors' manuscripts. In case of difficulty please consult the Photo-
reprographic Unit of your institution.
(a) Look at current Tables in the Journal, and arrange your 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.
(dl 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 (1950)—the date of publica-
tion, in parentheses, following (he author's name. References should be listed together at the end of each paper
and not given as footnotes. They should be arranged in alphabetical order (first author's surname) with the name
of the periodical abbreviated in the style of the World List of Scientific Periodicals (4th edn, Butterworths,
London, 1963-1965,3 vols) and appear as follows:
Fermi E. and Marshall L. (1947) On the interaction between neutrons and electrons. Phys. Rev. 72,1139-1146.
Thring M. W. (1957) Air Pa/lnlion, p. 132. Butterworths, 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 III
USANC
REIMBURSEMENT REQUEST
Expenses incurred relating to preparation of interpretive analysis of the
8th Biennial International Water Pollution Control Conference, Sydney, Australia,
October 17-23, 1976.
ITEM
Professional Services (collection/
assimilation/analysis of
information, report prepara-
tion, etc.)
days @ $ per day
*
Conference Registration
*
Subsistence During Conference
days @ per day
*
Travel Costs
— Within U.S.A.^
— International
TOTAL
***
AMOUNT
REIMBURSEMENT
***
REQUESTED
REIMBURSEMENT
APPROVED
**
***
Attach receipts (subsistence receipts required
only if amount exceeds 51 U.S. dollars per day
*
No international travel costs are reimbursable
*
Information needed for cost sharing
Signature
Social Security Number
For Coordinating Subcommittee Use Only:
Report Received (Date)
Report Accepted and Reimbursement
Approval (Date
Date and Amount Paid
Send the Voucher To:
Richard S. Engelbrecht
Department of civil Engineering
University of Illinois at
Urbana-Champaign
Urbana, Illinois 61801
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