EPA-600/2-76-195
December 1976
Environmental Protection Technology Series
               EVALUATION  AND  UPGRADING OF  A
        MULTI-STAGE TRICKLING  FILTER  FACILITY
                                  industrial Environmental Research Laboratory
                                       Office of Research and Development
                                      U.S. Environmental Protection Agency
                                              Cincinnati, Ohio  45268

-------
                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency,  have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping  was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:

     1.    Environmental Health Effects Research
     2.    Environmental Protection Technology
     3.    Ecological Research
     4.    Environmental Monitoring
     5.    Socioeconomic Environmental Studies

This report  has been  assigned  to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate  instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new  or improved technology required for the control  and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

-------
                                       EPA-600/2-76-195
                                       December 1976
    EVALUATION AND UPGRADING OF  A MULTI-

      STAGE  TRICKLING FILTER FACILITY
                     by

                John H.  Koon
              Robert F.  Curran
             Carl  E. Adams,   Jr.
        W.  Wesley  Eckenfelder,  Jr,
                AWARE,  Inc.
            Nashville,  Tennessee

                     and

           CIBA-GEIGY CORPORATION
           Cranston,  Rhode Island
             Project 12020 FOH
              Project Officer

            David H.  Stonefield
     Surveillance and Analysis Division
                  Region I
         Needham Heights,  MA  02194
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
    OFFICE OF RESEARCH AND DEVELOPMENT
   U.S.  ENVIRONMENTAL PROTECTION AGENCY
           Cincinnati, Ohio 45268

-------
                            DISCLAIMER

      This report has been reviewed by the Industrial Environmental
Research Laboratory, U. S. Environmental Protection Agency, and
approved for publication.  Approval does not signify that the contents
necessarily reflect the views and policies of the U. S.  Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
                                 ii

-------
                             FOREWORD
     When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory - Cincinnati
(IERL-CI) assists in developing and demonstrating new and
improved methodologies that will meet these needs both effi-
ciently and economically.

     This report evaluates the applicability of several
alternate treatment methods for complex organic waste waters and
documents the results of an in-depth study of a large scale,
multi-stage trickling filter system.  From the study, it was
concluded that the anticipated acclimation of the microorganisms
and enhanced BOD removal were not achievable but rather, that
undesirable air stripping of volatile organic constituents con-
tributed very significantly to apparent pollutant removal.

     This study is one of several undertaken by IERL-CI to
evaluate alternate systems for treatment of complex wastes and
reduction of'discharges to our Nation's waterways.  The report
alerts industrial waste system designers, state officials, and
EPA officials responsible for standard-setting to some of the
problems which must be anticipated even with relatively con-
ventional technology.

     For further information on this subject, contact the
Industrial Pollution Control Division,  Organic Chemicals and
Products Branch.
                                David G. Stephan
                                    Director
                  Industrial Environmental Research Laboratory
                                   Cincinnati
                               ill

-------
                           ABSTRACT
 The  applicability of a  full-scale, six-stage trickling filter plant
 was  investigated for the treatment of waste from a multiproduct
 organic  chemical plant.  Reductions of BOD per unit volume of packing
 indicated  that  the series design of the system did not lead to stage-
 wise acclimation of the microorganisms or enhanced BOD removals.  Tests
 to determine BOD removal mechanisms in the system indicated that air
 stripping  and biological mechanisms both contributed significantly to
 the  total  observed reduction.

 Effluent recycle considerably improved filter performance.  However,
 600  percent recycle was required for an approximate 90 percent re-
 duction of BOD  at a hydraulic loading of 2 gpm/sq ft (0.08 cu m/min-
 sq m).

 Bench-scale activated sludge investigations showed that this process
 could be used successfully for upgrading the trickling filter system.
 Kinetic parameters necessary for the design of activated sludge systems
 were determined.  Comparative studies of air and oxygen aeration indi-
 cated that the  treatment of wastes containing volatile substances might
 be difficult in a closed oxygen system.

 Activated  carbon adsorption,also tested in small-scale systems, was
 most effective  as a means of upgrading the trickling filter system
 when applied following activated sludge treatment.  Activated carbon
 tests indicated that some refractory organics and color-producing
 substances could be effectively removed by adsorption; however, a
 significant nonadsorbable organic fraction remained.

This  report was  submitted by  AWARE,  Inc.  in fulfillment of U. S.
Environmental  Protection Agency  Grant  12020 FOH to CIBA-GEIGY Corporation,
                                   iv

-------
                           CONTENTS
                                                         Page

Foreword                                                 i i i
Abstract                                                 iv
Table of Contents                                        v
List of Figures                                          vi
List of Tables                                           x
Sections
I      Conclusions                                       I
II     Recommendations                                   3
III    Introduction                                      4
IV     Description of Treatment Facility                 8
V      Experimental Procedures                           27
VI     Small-Scale Trickling Filter Investigations       44
VII    Full-Scale Trickling Filter Investigations        59
VIII   Automatic Monitoring                              78
IX     Activated Sludge Investigations                   82
X      Activated Carbon Investigations                   99
XI     Removal of Organic Constituents by Air Stripping  110
XII    Acknowledgements                                  125
XIII   References                                        126
XIV    List of Symbols and Abbreviations                 128
XV     Appendices                                         130

-------
                         FIGURES

No.                                                      Page
1      Correlation of Measured BOD to BOD                12
       Attributable to Solvents

2      Correlation of Measured TSC to TOC                13
       Attributable to Solvents

3      Wastewater Treatment Plant, CIBA-GEIGY            15
       Corporation Cranston, Rhode Island

4      Preliminary Treatment Facilities                  17

5      Trickling Filter Medium                           19

6      Schematic Illustration of Original                 21
       Trickling Filter Design

7      Trickling Filter Recycle System                   24

8      Wastewater Monitoring System                      26

9      Process Flow Diagram-Existing Full-Scale          28
       and Experimental Treatment Sequences

10     Schematic Illustration of Pilot Trickling         31
       Filter

11     Schematic of the Microtower Arrangement           33
12     Schematic Illustration  of Activated Sludge        35
       Units

13     Schematic Illustration  of Oxygen Activated        37
       Sludge Units

14     Schematic Illustration  of Activated Carbon        39
       Columns

15     Aerated Equalization and Stripping Basin          41

16     Variation of  Removal  Effluent with Applied        46
       COD Load
                             vl

-------
                      FIGURES (Cont'd)
No.                                                      Page
17     Removal Efficiency Versus Applied Organic         47
       Loading in the Recirculation Study
18     BOD and COD Removal Efficiency Versus Recycle     48
       Ratio
19     Effects of Organic Loading on Oxygen Uptake Rate  49
20     Oxygen Uptake Versus Recirculation Ratio          51
21     Oxygen Utilization in the Microtower              52
22     Fraction of COD Removal Due to Oxygen Uptake      54
       in the Microtower
23     Effect of Recycle on Pilot Trickling Filter       57
       Performance
24     Variation of Pilot Trickling Filter Performance   58
       and Organic Loading
25     Chronological Variation of BOD Removal             61
26     Relationship of Trickling Filter BOD Loading      63
       and Removal
27     Effect of pH Fluctuation on Trickling Filter      65
       Performance
28     Temperature Dependence of the BOD Removal Rate    67
       Constant
29     Variation of Solvent Concentration through the    69
       Trickling Filter System
30     Oxygen Uptake In, Full-Scale Filters              71
31     BOD Removal Rate Constant-Phases I and II         84
32     Temperature Effect on Activated Sludge            86
       Performance
                            Vll

-------
                      FIGURES (Cont'd)

No^                                                     Page

33     Determination of Oxygen Utilization               87
       Coefficients, BOD Basis-Phases I and II

34     Excess Sludge Production, BOD Basis-              89
       Phases I and II

35     BOD Removal Rate Constant, Unstripped             91


36     BOD Removal Rate Constant, Stripped Waste -       91
       Phase III

37     Performance of Oxygen - Acclimated Sludge         93
       Subjected to Air Aeration

38     Oxygen Utilization for Unstripped Waste,           94
       BOD Basis-Phase III

39     Oxygen Utilization for Stripped Waste,             94
       BOD Basis - Phase III

40     Summary of BOD Removal  Relationships for           97
       Activated Sludge Systems

41     Influence of pH on Carbon Adsorption Capacity     101

42     Breakthrough Curve - Hydrodarco 4000 Carbon       103

43     Breakthrough Curve - Westvaco 8 x 30 Carbon       103

44     Breakthrough Curve - Filtrasorb 400 Carbon        103

45     Color Removal  Breakthrough Curves for Hydro-      105
       darco 4000 and Westvaco 8 x 30

46     Color Removal  Breakthrough Curve for Filtra-      105
       sorb 400

47     TSC Breakthrough for Regenerated Hydrodarco       106
       4000

48     COD Breakthrough for Filtrasorb 400 Using         109
       Trickling Filter Effluent
                           Vlll

-------
                      FIGURES (Cont'd)
No.                                                      Page
49     TSC Removal in Batch Stripping Tests              111
50     Variation of Stripping Removal Coefficient        113
       with Temperature
51     Packed Tower Air Stripping Results,  BOD Basis     115
52     Linearized Data for Packed Tower Stripping -       116
       TSC Basis
53     Linearized Data for Packed Tower Stripping -       117
       BOD Basis
54     TSC Removal in Aerated Equalization  Basin-D.T.=   118
       1.5 Days
55     TSC Removal in Aerated Equalization  Basin-D.T.=   120
       3 Days
56     Organic Removals in the Aerated Basin             122

-------
                           TABLES

No.                                                      Page

1      Wastewater Characterization                       10

2      Solvent Determinations for Raw Equalized Waste    11

3      Stripping Results From Pilot Trickling Filter     56

4      Monthly Trickling Filter Performance              62

5      BOD Removal  Attributable to Oxygen Uptake         72

6      Effect of Tower Blowers on Dissolved Oxygen       74
       Level  and Total Carbon Removal

7      Recycle Data Summary                              76

8      Comparative  Dissolved Oxygen Measurements         79

9      Summary of Activated Sludge Design Parameters     96

10     Carbon Isotherm Results Using Activated           100
       Sludge Effluent

11     Comparison of Results for Activated Carbon        107
       Adsorption of Activated Sludge Effluent

12     Summary for  Stripping in Aerated Basin            119

13     Solvents Measured in Stripping Investigations     123

Al     Treatment Facility Capital Cost Summary           131

A2     Treatment Facility Operating Cost Summary         132

Bl     Trickling Filter Weekly Data Summary              133

B2     Full-Scale Trickling Filter Recycle Data          134

Cl     Summary of Activated Sludge Results-Phase I       135

C2     Summary of Activated Sludge Results-Phase II       135
                             X

-------
                      TABLES (Cont'd)

No.                                                      Page

C3     Summary of Activated Sludge Results,               137
       Varied Temperature Operation -  Phase  II

C4     Summary of Activated Sludge Results - Phase  III    138
                            xi

-------
                           SECTION I

                          CONCLUSIONS
1.  Over the period of this investigation, the six-stage trick-
    ling filter system removed only 32 percent of the effluent
    BOD load.  The effluent BOD averaged 2,180 mg/1.  Due to ex-
    treme organic overloading in the system, no stage-wise
    acclimation of microorganisms was observed.  The quantity
    of BOD removed in the system ranged from approximately 100
    to 200 lb/1,000 cu ft-day (1.5 to 3 kg/cu m).  Since removals
    of this magnitude are not uncommon for single-stage, plastic
    medium trickling filter systems, it cannot be concluded that
    multiple staging resulted in extraordinarily high removals/
    unit volume for this waste.

2.  Recycle investigations in three stages of the full-scale
    system demonstrated that approximately 50 percent BOD re-
    moval could be achieved at 20°C using a recirculation ratio
    of 2.3.  However, while recirculation improved filter per-
    formance, these results and small-scale trickling filter
    tests indicated that BOD reductions higher than approximately
    90 percent could not be achieved at recycle ratios as high
    as 800 percent.  For this high strength waste (initial  BOD of
    3,200 mg/1), this level of treatment would probably be
    inadequate in most instances.

3.  The six-stage trickling filter system, even when modified
    to include effluent recycle, failed to produce acceptable
    results as the sole treatment method for the wastewater.
    Due to the failure of the system to provide extraordinarily
    high organic removals, their multi-stage design can be used
    only as an initial treatment step.

4.  Investigations made using the small-scale trickling filter
    to determine the mechanism of BOD removal indicated the
    principal removal mechanism at low recycle ratios was by
    air stripping, but that the fraction of BOD removed by air
    stripping decreased significantly as the recycle rate was
    increased.

-------
The annual  treatment cost for the 1.44 mgd facility including
neutralization, equalization, trickling filtration in a six-
stage system, and clarification totaled $690,000/yr including
capital  and operating and maintenance costs.   This was equiva-
lent to  $1.58/1,000 gal  and $0.19/lb BOD removed.

Bench-scale activated sludge investigations showed that this
process could be used to upgrade the trickling filter effluent.
Treatment of the waste was characterized by a relatively high
oxygen demand per unit of BOD removed, a relatively low sludge
yield, and poor oxygen transfer characteristics.  The effluent
was characterized by high effluent suspended solids concentra-
tions ranging from 90 to 175 mg/1 and a high refractory effluent
COD of approximately 450 mg/1.

Performance of the activated sludge process was significantly
impaired using pure oxygen aeration in a closed atmosphere
system treating the unstripped raw wastewater.  However,
performance using aeration treating a stripped waste was equal
to or better than that obtained with air aeration.

Activated carbon adsorption was capable of removing refractory
organic substances from the activated sludge effluent.  Results
indicated that treatment of the trickling filter effluent using
this process would be feasible following removal of high con-
centrations of short-chained solvents.

Results of air stripping investigations showed that a signi-
ficant fraction of the raw waste organics could be removed in
an aerated equalization basin with surface aerators and in
packed towers such as trickling filter systems.  In order to
achieve 60 percent BOD reductions, an air flow of 500 cu ft/gal
was required in the packed tower, while a 3-day detention time
using 150 hp/mil gal aeration capacity was required in the
basin.  These results indicate that the effects of stripping
especially as they relate to scale-up from small-scale systems
can be significant in designing biological systems to treat
wastes containing volatile substances.

-------
                         SECTION II

                       RECOMMENDATIONS
1.  The results of this investigation indicated that waste pro-
    duced in the manufacture of miscellaneous organic chemicals
    can be treated using both biological and physical-chemical
    processes.  However, the complexity of the waste and large
    fluctuations in waste composition caused by changes in pro-
    duction schedules dictate that long-term responses of ap-
    plicable treatment systems be thoroughly considered prior
    to preparing a final design.  Primary consideration should
    be given to designs in which fluctuations in concentration
    and composition have a minimum effect on system performance.

2.  In designing plastic medium trickling filters it is impor-
    tant that consideration be given to the structural stability
    of the packing and additional requirements for vertical  and
    lateral supports in the tower superstructure.  Packing such
    as the one used in this design has a minimum ability to
    support vertical and lateral loads and, therefore, must be
    strengthened by more complex supporting structures than
    would be required for other commercially available packing
    designs.

3.  Effluent recirculation should be included in trickling fil-
    ters designed for treatment of high-strength industrial
    wastes.

4.  In designing multi-stage trickling filters, care should be
    taken not to overload the first stages of a system to the
    extent that failure of the entire system will be experienced.

-------
                           SECTION III

                          INTRODUCTION
Wastes from many organic chemical  plants typically contain sig-
nificant concentrations of short-chained organics used as sol-
vents and lesser concentrations of more complex organic substances.
In comparison to municipal sewage, these wastes are highly vari-
able in composition depending on plant production schedules, are
composed principally of soluble organic substances which cannot
be removed by precipitation or adsorption onto biological floes,
and may contain exotic chemical species which would interfere
with conventional treatment processes.  When treating wastes of
this type, biological processes would be most effective in re-
moving short-chained and other degradable organic constituents,
while physical and chemical processes, such as adsorption using
activated carbon, would be required to remove substances refractory
to biological treatment.

The purpose of this project was to evaluate the use of multi-
stage trickling filters and other methods for treating wastes
produced in a diversified organic chemicals plant.  The project
involved demonstration of a full-scale, six-stage plastic medium
trickling filter for reduction of organic constituents in the
wastestream and the investigation of other potential treatment
methods.  Advantages which might be attributed to the multi-stage
trickling filter include the sequential development of micro-
organisms in the system acclimated to the different organic con-
stituents in the waste.  If this were the case, greater removals
of organic constituents per unit volume might be experienced com-
pared to conventional trickling filter designs.  Small-scale
tests using the activated sludge and activated carbon processes
were performed to determine the applicability of these methods
for further treatment of the waste required to meet anticipated
best practicable and best available treatment technology.


BACKGROUND INFORMATION

The CIBA-GEIGY plant located at Cranston,  Rhode  Island is a multi-
product organic  chemicals plant in which over  500 different raw
materials are used to make more than 200 different  chemical pro-

-------
ducts.  Products manufactured in the plant include plastic additives,
Pharmaceuticals, dyestuffs and intermediates, and miscellaneous
chemicals.  The products produced here are destined for use largely
in the plastics, leather, textiles and paper industries.  Because
of the diversity of products produced in the plant, it is difficult
to precisely relate the plant production to the nature of the waste-
waters produced.  During 1973, 30,000,000 Ib of products were manu-
factured in the plant.  The production was distributed among various
product categories as follows:  Pharmaceuticals, 3 percent; plastic
additives such as antioxidants, 59 percent; chemical  products (mostly
fluorescent whitening agents and textile auxiliaries), 26 percent;
tanning agents, 11 percent; and printing inks, 1 percent.

Situated on the Pawtuxet River approximately one mile upstream from
Narragansett Bay, the plant is known for its modern facilities and
versatility.  Due to the extensive development and pilot plant
facilities located at this site and the diverse nature of products
manufactured in the plant, it has become known within CIBA-GEIGY
Corporation as the "pilot plant of the world."

Originally, wastes generated in the plant were discharged through
numerous outfalls to the Pawtuxet River.  When it was recognized
that direct disposal of untreated wastes to the river was unaccepta-
ble, a long-term wastewater management program was implemented in
the plant.  In 1965 cooling water used in the plant was separated
from process discharges and combined in a recirculated cooling
system.  Approximately 7 mgd (26,000 cu m/day) of cooling water
is recirculated through the plant.

In order to reduce process waste discharges, certain  solvents and
acids were segregated and either cleaned, concentrated and recycled
or transported away from the plant for proper disposal.  Having
isolated most materials which lent themselves to this type of
treatment, it was realized that additional treatment  of wastes
would be required.  Investigations were initiated in  July, 1965
to evaluate alternative means for treating and disposing of wastes
in the plant.  After considerable study a decision was made to
construct a multi-stage plastic medium trickling filter system.
This system was designed and constructed by Biodize Systems,
Enviro-Chem Division of Monsanto Company and was placed in opera-
tion during the spring of 1972.

In 1970 CIBA-GEIGY Corporation received a research and development
grant from the Environmental Protection Agency to evaluate the
multi-stage trickling filter system over a two-and-one-half year
period.  Following start-up of the system, CIBA-GEIGY Corporation
retained Associated Water and Air Resources Engineers, Inc. (AWARE)
to perform the on-site investigations associated with the demon-
stration grant.  In November, 1972 investigations were initiated.

-------
THE APPLICATION OF MULTI-STAGE TRICKLING FILTERS

Although most work relating to pilot- and full-scale trickling
filter installations has been concerned with plants in which only
a single stage is employed, two- and three-stage systems are not
uncommon.  Advantages of multi-stage systems which have been
advanced in the past include:  greater flexibility in treating
high-strength wastes to levels acceptable for discharge and the
development of varied microbial  populations from one stage to
the next which might provide greater organic removals compared
to a single stage having an equivalent volume.   The primary dis-
advantage of multi-stage filters is the tendency to organically
overload the first stages of the system.

Good performance of plastic medium, multiple-stage trickling fil-
ters has been reported for numerous industrial  effluents (1, 2).
Food processing industries routinely use  multiple-stage plastic
filters in the treatment of wastes from dairies, meat packing
plants, fruit and vegetable processing plants,  potato processing
plants, and breweries (3, 4).  In one case, a four-stage system
was designed to treat a very strong pharmaceutical  effluent (3, 5).
The design included a series of four plastic filters, each with
individual recycle and an individual  settling tank (although inter-
stage clarification is not considered essential) followed by a
fifth stage consisting of a six-foot granite polishing filter.
Recirculation ranging from 100 to 200 percent was practiced within
each stage.

The effect of effluent recirculation cannot be  predicted a priori
in any single case.  In certain cases, negative effects have been
reported.  For the case of concentrated industrial  effluents,
however, most researchers have reported beneficial  effects of
recirculation (6, 7, 8).  This is due to  enrichment of  specific
enzymes, aeration, adsorption of inhibitory compounds,  dilution,
and dampening of short-term raw waste load  variability.

Equally opposed opinions have been expressed concerning the exist-
ence of a limiting organic loading.  The  limiting loading is
defined as a load beyond which the BOD removal  decreases.   The
existence of such a loading has been considered by  numerous in-
vestigators (9-13).  Other authors, working primarily with plastic
media, reported no limiting loading (14,  15).

-------
OBJECTIVES

The principal objectives of this investigation were to evaluate a full
scale multi-stage plastic medium trickling filter system for the
treatment of waste from a diversified organic chemical plant
and to determine the applicability of the activated sludge and
activated carbon processes for further treatment of the waste
as judged by tests in small-scale systems.  Specific objectives
outlined in the grant application were modified during the course
of the investigation by joint agreement between CIBA-GEIGY
Corporation and the U.S. EPA.  The restructured objectives of
the investigation were as follows:

1.  To optimize operation of present treatment facilities.

2.  To examine operation of the multi-stage trickling filter
    system at various organic loads, temperature conditions,
    and other operating variables.

3.  To investigate BOD removal mechanisms in the trickling filter
    system and to determine whether stage-wise acclimation of
    microorganisms occurred.

4.  To evaluate the feasibility of using automatic monitoring
    equipment for the control of trickling filter systems.

5.  To examine the activated sludge process as a means of further
    treating the waste and to determine the kinetic parameters
    required for a process design.

6.  To examine activated carbon adsorption as a means of reducing
    BOD and removing refractory organic materials.

Personnel  from AWARE,  Inc.  were responsible for sampling,  operation
and care of experimental  treatment units and compilation  and pre-
sentation of all  data  obtained from the project.   CIBA-GEIGY per-
sonnel were responsible for the conduct of all  analytical  work, the
operation and maintenance of automatic monitoring equipment and
the conduct of effluent recycle investigations  in the full-scale
trickling filter system.

-------
                           SECTION IV

                DESCRIPTION OF TREATMENT FACILITY
Although this project was concerned primarily with the perfor-
mance of the multi-stage trickling filter system,  several  other
unit operations were required for treatment of the complex
chemical waste discharged.  The several  unit operations included
in the entire treatment system and characteristics of the influ-
ent waste are discussed in this chapter.
SOURCES OF WASTEWATER

The complexity of waste treatment problems at the Cranston plant
is indicated by the large number of products produced in the
facility and by the variety of manufacturing processes employed.
Production of the great number of products required from this
plant necessitates the use of batch processing methods which
usually generate greater quantities of waste than comparable
continuous-flow production methods.  Since each reactor or
"kettle" is used for producing a large number of products, segre-
gation of wastes would be impossible.   It is often common for
products to be manufactured during "campaigns" lasting several
weeks during which several months' supply of a particular product
is produced.  Therefore, in addition to daily fluctuations in
wastewater strength and composition, significant weekly and
longer-term variations are also evident.

The manufacturing plant consists of six buildings containing
over 100 independent reactor units varying in size up to
3,000 gal (12,000 liters).  In addition to agitated vessels,
reaction units include appropriate auxiliary equipment such as
distillation columns, condensers, receiving vessels, many types
of filters and dryers and associated material transfer equipment.

Because of the many different reaction cycle times, no fixed
number of batches per day can be quoted.   However, the plant
operates on a 24 hr/day basis and material transfer operations
are in progress simultaneously on anywhere from 5 to 25 percent
of the equipment.

Sources of wastewater include:  1) detergents, solvents, and
other materials used to clean kettles, 2) solvents and other

-------
materials used to wash and purify products, 3) filtrates and
centrates from product dewatering and drying, 4) water from vacuum
jets, 5) blowdown from a recirculating cooling system, 6) still
bottoms, 7) materials used to clean floors in production areas,
and 8) stormwater run-off from the production area.  Wastewater
from manufacturing areas is collected in the plant sewer system
and conveyed to the main pumping station.  Based on the use of
city water recorded in the production area and the quantity of
wastewater received at the treatment plant, there is very little
water loss in the plant due to evaporation or packaging with pro-
ducts.  Comparison of these flows over the duration of the study
showed that recordings from the magnetic flow meter in the treat-
ment plant were approximately 15 percent greater than water meter
readings.  Some difference would be expected due to the intro-
duction of stormwater flows to the plant sewer.

During most of the study period, work in the manufacturing areas
proceeded 24-hr/day, 6 days/wk.  However, at times the work
schedule was decreased to a 5-day week or increased to 7 days/wk
depending upon inventory backlogs.  During periods when the plant
was not operating, the waste flow averaged approximately 200 gpm
(0.8 cu m/min) due to water used for vacuum jets and cooling
systems.
WASTEWATER CHARACTERIZATION

Twenty-four hour composite samples of wastewater were collected
over the nine month period from November 1972 through July 1973
and analyzed for BOD, COD, TSC (total carbon test performed on
filtered wastewater, total soluble carbon), suspended solids,
volatile suspended solids, color and temperature.  The results of
these and other tests performed on the wastewater are summarized
in Table 1.  The waste contained a high concentration of organic
material, demonstrated by a total influent BOD of 3,190 mg/1  and
a total influent COD of 4,676 mg/1.   The BOD/COD ratio of the raw
waste was 0.68.  At median concentrations approximately 90 per-
cent of the total BOD and COD was in the soluble fraction, due
largely to solvents present in the wastewater.  Weekly grab sam-
ples were analyzed to determine the concentrations of various
solvents.  The ranges and average values for these solvents are
shown in Table 2.

In order to determine the approximate fraction of the total organic
waste load due to solvents, the BOD attributable to each solvent

-------
                             TABLE 1




                    WASTEWATER CHARACTERIZATION
Parameter
Flow3 (mgd), all days
Weekdays
BOD (mg/1) Total
Soluble
COD (mg/1 ) Total
Soluble
TSC (mg/1)
Suspended solids (mg/1)
Volatile suspended solids (mg/1)
Total kjeldahl nitrogen (mg/1)
Total phosphorus (mg/1 )
Alkalinity (mg/1 as CaCOo to pH 3.7)
Total solids (mg/1)
Color (APHA units)
Temperature (°F) Influent
Effluent
Average
1.26
1.48
3190
3090
4676
4100
1200
151
131
37
6
227
2725
1800
—
—
Percenti le Values
10%
0.48
1.12
1400
1200
2400
2100
620
48
44
2.5
2.2
155b
1500°
400°
57
52
50%
1.42
1.54
3000
2600
4650
4150
1220
108
100
30
3.8
—
—
—
67
62
90%
1.64
1.68
5050
4750
6900
6200
1830
288
250
94
13.
282°
4860°
4000D
77
72
Flow in cu m/day = mgd x 3790-



Values are minimum and maximum  observed.
                                 10

-------
                             TABLE 2

         SOLVENT DETERMINATIONS FOR RAW EQUALIZED WASTE
Solvent
Acetone
Methyl ethyl ketone
Methanol
Isopropyl alcohol
Toluene
Concentration (mg/1 )
Average
280
20
220
1,260
120
Range
30-600
10-100
0-700
500-3,100
0-300
was calculated and correlated to the total BOD of the influent
waste as shown in Figure 1.   This correlation indicates that
approximately 61  percent of the BOD was due to solvents.   In a
similar manner total carbon  values were calculated for each sol-
vent analysis.  The results  shown in Figure 2 indicate that
practically all  of the total  carbon may be attributed to  the
solvent load.  However, while total carbon values for the sol-
vents were theoretical, less  than 100 percent total  carbon can
be measured by any laboratory procedure used for the influent
waste.   Relationships were developed between total BOD and COD
and between soluble BOD and  TSC, resulting in the following
equations:

                    BODT = 0.788 (CODT) - 420

                    BOD$ = 2.65 (TSC) - 382

The suspended solids content  of the waste averaged 151 mg/1;
however, a significant fraction of the solids was very highly
dispersed and non-settleable.  Volatile suspended solids  com-
prised  87 percent of the total suspended solids.  Nitrogen and
phosphorus concentrations of  the raw wastewater were determined
from composite samples collected from mid-November to mid-
December of 1972.  The quantities present would be insufficient
                             11

-------
        5000 r
        4000
      z
      u
      >


      8 3000

      o
      h-

      LU
      _J

      < 2000
      m
      ir
        1000
      Q
      O
      CD
          0
I Slope = 0.61
           0
1000    2000    3000    4000    5000

      INFLUENT WASTE BOD (mg/l)
              6000
FIG. I . CORRELATION OF  MEASURED BOD TO BOD ATTRIBUTABLE
      TO SOLVENTS

-------
  2500
~ 2000
V)
8  1500
UJ
_j
CD


ID
go
oc


<

o
o
  1000
   500
     0
        Regression Line

        y= 0.818 xt 203

        r=0.7l
Visual best fit
through origin



I   i
                                    I
      0
                    500
             1000

        RAW  WASTE TSC (mg/l)
1500
2000
FIG. 2 . CORRELATION OF MEASURED  TSC  TO  TOC  ATTRIBUTABLE

       TO SOLVENTS

-------
to maintain a high level of biological treatment; therefore,
nutrients must be added to this wastewater prior to biological treat-
ment.  Total solids, determined from samples composited over one-
week periods, averaged 2,725 mg/1  in the influent waste and 3,800
mg/1 in the trickling filter effluent.  The alkalinity determinations
made from July 13 to July 20, are  significantly greater than would
be expected from the low inorganic carbon concentration and might
have been due to organic constituents present in the waste,
 PLANT DESIGN
Haste Collection and Transport

All  process wastes from the manufacturing area in the plant flow
through a central sewer system and are subsequently collected
in  a raw wast0 pumping station.  All sanitary wastes from the
analytical and development laboratories are discharged separately
to  the municipal sewer system.  In addition to process waste-
waters, stormwater runoff from some material storage areas  is
collected in  the pumping station.  Because of the highly variable
pH  of process waste discharges, the raw waste collection sump  is
lined with an acid-alkali resistant brick.  Waste is pumped from
the sump to the treatment plant using two 1,250 gpm (5 cu m/min),
acid resistant pumps constructed of a high nickel stainless
steel.  Each  pump is capable of handling the average plant waste
flow of 1,000 gpm (4 cu m/min).  To insure that raw waste is not
discharged during power failures, a back-up power supply consist-
ing of gas-operated generators is provided for operation of the
raw waste and equalization basin influent pumps.  Prior to enter-
ing the sump, all waste is screened through a mechanically-cleaned
bar rack in order to remove extraneous materials discharged to the
plant floor drains.

From the pumping station waste is transported through a polyester-
fiberglass pipe approximately one-quarter mile to the treatment
plant site.   This particular construction was required in order
to  provide adequate resistance to acid, alkali, and solvents
which might be present in high concentrations prior to equaliza-
tion and neutralization.  A photograph of the treatment facility
is  shown in Figure 3.
 Preliminary  Treatment

 Preliminary  treatment  processes  include solvent separation, flow
 measurement,  neutralization, equalization, and nutrient addition.
                                 14

-------

FIG. 3 .WASTEWATER TREATMENT PLANT, CIBA-GEIGY CORPORATION
     CRANSTON, RHODE ISLAND

-------
A schematic illustration of pretreatment facilities is shown in
Figure 4.

Due to the possibility that large spills of solvents might occur
in the plant, facilities are provided to separate immiscible sol-
vent loads from the wastestream.   This is accomplished in a
45,000 gal (180 cu m) cylindrical tank.   Waste enters the tank
through a tangential  inlet in order to maintain most solids in
suspension and yet allow separation of any immiscible solvents.
In addition to serving as a solvent separator, the tank provides
some equalization of pH and flow prior to the neutralization
system.   Immiscible solvent layers are withdrawn through a tan-
gential outlet into a 5,000 gal  (20 cu m) solvent holding tank.
Collected solvents may be trucked away for ultimate disposal or
transported to the manufacturing area for reclamation and reuse.

In order  to provide collection of large solids which settle in
the solvent separation tank, the tank bottom slopes to one side
which  is  equipped with a valved outlet suitable for wasting
sludge.   Sludge is usually collected in 55-gal (200 liter) drums
as necessary and taken for disposal with other concentrated
wastes from the manufacturing area.
Flow Measurement and Neutralization.   Waste is pumped from the
solvent separation tank into the control  building where the flow
is metered and the waste neutralized.   The waste flow is meas-
ured using a magnetic flow meter attached to the raw waste force
main.  Neutralization is accomplished in  a one-stage, tubular
reactor which was constructed by baffling an 8-ft (2.4 m) section
of pipe in the raw waste force main.   Probes are located at the
downstream end of the reactor to monitor  and control  pH.  Con-
trollers are coupled to transmitters  and  automatic valves which
control acid and caustic additions to the wastestreams.  Concen-
trated sulfuric acid and 50 percent sodium hydroxide are used
to neutralize the waste.

Equalization.  Following neutralization the waste is stored in
two, 1-mil gal (4,000 cu m) equalization  tanks.   These cylindri-
cal steel tanks are 100 ft (30 m) in  diameter with a depth of
approximately 20 ft (6 m) and are located above grade.  Together
they provide a holding time of approximately 1.5 days for the
plant design flow of 1.4 mgd (5,600 cu m/day).   Each tank is
lined with a phenolic material  to prevent corrosion.
                                16

-------
          BAR
         SCREEN
TO
TRICKLING
 FILTERS
  RAW
WASTE
PUMPING
 SOLVENT
SEPARATION
                                        TO
                                       TRICKLING
                                        FILTERS
                                     §-a
                                     8--Q
                                                            SOLVENT
                                                            STORAGE
                                                          FLOW
                                                      MEASUREMENT
                                                   NUTRIENT
                                                   ADDITION *
                                                      NEUTRALIZATION
                        EQUALIZATION

         Nutrient addition shown as modified in 1973.
               FIG. 4 PRELIMINARY  TREATMENT FACILITIES

-------
Flow enters the tanks through diffusers which were constructed
across the bottom of each tank approximately 2 ft (0.6 m) from
the bottom.  Two 1,000 gpm (4 cu m/min) pumps convey the waste
from the equalization tanks to the trickling filter system.

It was originally planned that the inlet diffuser system would
provide sufficient mixing for equalization and would prevent
solids from settling in the basin.  However, a significant
quantity of sludge accumulated during the first year of opera-
tion which dictated the need for mechanical mixers.   Subse-
quently, a 40-hp (30 kw) mixer equipped with a marine-type
propeller was installed in the side of each tank.  Since that
time no problems have been encountered due to the accumulation
of solids in the tank or to poor equalization because of
stratification.

Nutrient Addition.   According to the original plant design, an-
hydrous ammonia and 75 percent phosphoric acid were added to
the wastestream as it was pumped from the equalization basin
to the trickling filter system.   However, several problems
were encountered in obtaining adequate control  over nutrient
addition which resulted in severe pH shocks to the biological
system.  Subsequently, piping modifications were made to
permit nutrient addition prior to equalization.
Trickling Filtration

The trickling filtration system consists of six, 20-ft (6 m)
deep trickling filters designed to operate in series.  The fil-
ters were constructed in two rectangular banks with each bank
containing three stages.  Each stage consists of a 20 ft x 25
ft (6 m x 8 m) surface area packed with 10,000 cu ft (300 cu m)
of plastic packing.  The packing is supported by metal gratings
in four, 5-ft (1.5 m) sections.  Waste is distributed to each
stage through fixed nozzle distributors.

The plastic packing is illustrated in Figure 5.  The material
is constructed from polyvinyl  chloride and resembles a corru-
gated expanded metal  grating.   The corrugations are approxi-
mately 1 5/8 in.  (4 cm)  high.   The packing was placed horizon-
tally in each trickling  filter tower with corrugations placed
at right angles with each other in alternate layers.

Waste is collected beneath each tower in a sump having a capa-
city of approximately 15,000 gal  (60 cu m).  Since the bottom
                               18

-------
FIG. 5 . TRICKLING FILTER
MEDIUM

-------
of each sump is flat, sludge which accumulates in corners of the
basin sometimes produces objectionable odors during summer months.
A schematic illustration of the trickling filter system is shown
in Figure 6.

Piping provided in each tower permits the following flow arrangements;

1.  Under normal operation, waste is pumped from the equalization
    tank or from the preceding column up the riser to the distribu-
    tion system at the top of the subsequent tower.

2.  In order to provide for repairs, flow may be bypassed around
    one, or any number, of towers.

3.  Flow may be recycled in any particular tower.

In addition, provisions were included to pump waste directly to the
sump of the first trickling filter, thereby bypassing equalization
facilities, or to recycle flow from Tower 6 to Tower 1  in order to
provide flow through the system during periods when no raw waste is
available.  Each stage is provided with a 1,000-gpm (4 cu m/min)
pump driven by a 25-hp (19 kw) motor.  Pumping from each sump is
controlled by level indicators in the sumps which are connected to
control valves located on the outlet side of each pump.

Ventilation in the system is provided by a 10,000 cfm (28 cu m/min)
blower mounted at the base of each tower which is driven by a 7.5-
hp (5.6 kw) motor.  Air is forced up through the trickling filter
and exists through one 4 ft x 4 ft (1.2 m x 1.2 m)  port  located
in each trickling filter bank.

Final  clarification is provided in a 10-ft (3 m) deep clarifier
having a diameter of 50 ft (15 m).  The overflow rate for design
conditions is 730 gpd/sq ft (30 cu m/day-sq m).  Sludge  is dis-
charged to the city sewer and subsequently handled in the Cranston,
Rhode Island municipal  wastewater treatment plant.

Both the trickling filter system and the final clarifier were con-
structed above grade.   Due to a high groundwater level  in the treat-
ment plant area, above grade construction was employed.   Since the
plant is located adjacent to a residential  area, it was  necessary
to enclose the trickling filter structures, except for one air
discharge port in each  bank, in order to minimize the escape
of biological  odors to  the surrounding community.
                                20

-------
N5
           From
        Equalization
       By pass from
       Neutralization
( ;»


j
\ _.
r

£>
t>

°x
a
3. y

MI >ii
TOWER


!
D
,
/^v
-o
J
*

D
i
y - —
^ v

ill III
TOWER
2



y —
iS y

!l^ III
TOWER
4

£_i
*-

t

  • A TRICKLING FILTRATION CITY SEWER i RWTUXET RIVER .CLARIFICATION FIG.6.SCHEMATIC ILLUSTRATION OF ORIGINAL TRICKLING FILTER DESIGN

  • -------
    DESIGN EVALUATION
    
    Several problems were encountered with the original design.  Two
    of these have been mentioned in the previous discussion:  the
    addition of nutrients downstream from neutralization and equali-
    zation facilities and the absence of mixers in the equalization
    basins.  Additional problems which have been encountered are
    discussed below.
    
    The neutralization system, originally designed as a tubular re-
    actor, provided poor pH control.  As a short-term solution to
    this problem, waste was neutralized on a batch basis in the
    equalization tanks during most of this investigation.   Using a
    procedure developed by the plant operator after the plant was
    in service, waste was introduced into one tank until approxi-
    mately 80 percent of the total capacity was reached.  Subse-
    quently, a sample was taken and titrated to neutrality in the
    plant laboratory.  The quantity of acid or caustic required to
    neutralize the waste was calculated from the titration and
    metered into the tank with the influent flow.   Following a 15
    min mixing period, another waste sample was taken from the tank
    and checked to insure that the pH was within acceptable limits
    for feeding to the trickling filters.  As one tank of neutralized
    waste was fed to the trickling filters, raw waste was collected
    in the other equalization basin.  Although it has been proven
    that this method can reliably be used by plant operators for
    controlling the wastewater pH, the capacity of the equalization
    system to absorb fluctuations in waste strength was sacrificed.
    A more suitable neutralization system is presently being designed.
    
    The adequacy of the equalization system was not specifically
    evaluated during this project.   While it appears that the system
    is probably adequate to absorb short-term fluctuations in waste-
    water strength and flow when the plant is operated 7 days/wk,
    the equalizing capacity of the system is somewhat impaired by
    the use of two parallel  basins.   Considering the difficulties in
    operating two parallel  basins in such a manner to maximize equali-
    zation of the wastewater, the design of one larger basin would
    have provided more control  over equalization of the waste.
    
    Structurally, the trickling filters are supported on an external
    galvanized steel  framework.  Each 5-ft section of packing is
    supported  on  a  structural  steel  framework extending throughout
    each tower.   The system is  designed to support an interior load
                                   22
    

    -------
    of 80 Ib/cu ft.  Originally, the towers were wood impregnated
    with a decay-resistant chemical and were designed to support
    an interior load of 20 Ib/cu ft.  They suffered a complete
    structural failure soon after startup.
    
    Failure of the tower system was enhanced by the lack of lateral
    support for the packing.  Compression of the corregated-type
    packing when loaded with the slippery, biological slime resulted
    in lateral force within the columns in addition to the vertical
    load of the wet biota.  Visual inspection of the packing, shown
    in Figure 5, indicates that this packing would have significantly
    less strength when subjected to both lateral and compression
    loads than compared to other commerically available plastic
    packing.
    
    The capability to recycle effluent and mix it with the raw waste
    was not included in the original design.   The advantages of efflu-
    ent recirculation have been disputed in many applications.  However,
    recirculation should be considered in treating all high-strength
    industrial wastes since it provides recycling of nutrients and
    active microorganisms to the head of the system, dilution of the
    influent organic concentration, and dampening of fluctuations in
    the influent waste load.
    
    During the fall and winter of 1973, the system was modified to
    provide continuous effluent recycle.  A schematic diagram showing
    piping modifications for recycle is shown in Figure 7.   The six-
    stage system was modified to allow operation as two parallel
    units, each containing three filters in series.  Flow pumped from
    the equalization tanks is split to Towers 1  and 4 using orifice
    plates and pressure-actuated control valves.   Raw waste is com-
    bined with recycle flow at the top of Towers 1  and 4 and flows
    sequentially through three towers.  Effluent from Towers 3 and 6
    is split using sump level controllers (not shown in Figure 7)
    and an orifice plate meter, which is coupled to another control
    valve.  A preset flow is returned to the head of the system for
    recycle.  The balance of the flow, as sensed by the sump level
    monitors, is pumped to the final clarifier.
    TREATMENT COSTS
    
    A summary of treatment costs incurred for this plant are summarized
    in Appendix A.  Table A-l shows capital costs for the plant as
    estimated immediately following construction.  Since the plant
    was built under a turnkey contract, it was not possible to obtain
                                    23
    

    -------
    to
               From	
               Equalization
               Tank
                           Existing Piping
                           •New Piping
                                   FIG. 7. TRICKLING FILTER RECYCLE SYSTEM
    

    -------
    exact costs in all cases.   In particular, no delineation of
    major electrical costs or piping costs (included in "Site Work")
    were available.  It should  be noted that the cost given for the
    trickling filters reflects  the original wooden superstructure
    and not the steel and fiberglass structure constructed after
    the collapse of the original system.
    
    The operating costs listed  in Table A-2 are for 1973 which was
    the first year of operation following startup of the reconstructed
    plant.  Part of the cost given for "Supervisory and Administrative
    Labor" included salary and  other costs for the plant environmental
    supervisor whose duties were not completely related to treat-
    ment plant operation.  While "Laboratory and Analytical" costs
    were somewhat high compared to other industrial plants, this level
    of testing will probably be required to adequately monitor a plant
    treating such a complex waste to insure compliance with permit
    limitations.  Maintenance costs reflected startup problems which
    occurred during the year.
    
    In order to calculate treatment costs on a volume and performance
    basis, it was assumed that  the plant would generate 1.4 mgd of
    waste for 310 days/yr (6 day/wk operation) and that 11,900 Ib/day
    of BOD would be removed for each plant operating day (equivalent
    to 32 percent removal from an influent BOD of 3,200 mg/1  observed
    during this study).  In order to obtain an annual  cost for the
    capital cost of the system, an interest rate of 7 percent and a
    life of 10 years was assumed.  Thus, the amortized cost was
    $263,000/yr.  When combined with the annual operating cost of
    $327,000/yr, the total annual cost was $690,000/yr.  This is
    equivalent to costs of $1.58/1,000 gal of waste treated and
    $0.18/lb BOD removed.
    INSTRUMENTATION SYSTEMS
    
    In order to determine the applicability of this system to auto-
    mated control, an Ionics on-line total carbon monitoring system
    and a Weston and Stack dissolved oxygen system were installed in
    the treatment plant.
    
    A schematic illustration of monitoring points in the system is
    shown in Figure 8.  The total carbon analyzer and all recorders
    were installed in an instrument building located adjacent to
    Tower 3   Dissolved oxygen probes were located to monitor the
    contents of the effluent from each tower and the final clanfier.
                                    25
    

    -------
                 r
    FROM	
    EQUALIZATION
    TANKS
                                                                             I
                                                                  CLARIFIER
                                                                DO-Dissolved Oxygen
                                                                TC -Total Carbon
                       FIG.8.WASTEWATER MONITORING SYSTEM
    

    -------
                                SECTION V
    
                         EXPERIMENTAL PROCEDURES
    Due to the diversity of the tests conducted and the processes
    evaluated in this investigation, the experimental equipment
    utilized during the course of the study varied depending on
    the specific phase of the project.  Trickling filter studies
    were carried out using a single-stage microtower which was
    small enough to be operated indoors.  A two-stage pilot trick-
    ling filter was constructed on-site at the CIBA-GEIGY plant
    for use in other parts of the study.  Activated sludge inves-
    tigations using air aeration were performed in 40-gal (150
    liter) pilot units which were later sealed for use in the
    oxygen aeration investigation.  Activated carbon tests were
    made using 1-in. (2.5 cm) and 4-in. (10 cm) column units.
    In this chapter the equipment and operating procedures, analyti-
    cal methods, and data correlation procedures employed during the
    study are described.
    CONDUCT OF THE INVESTIGATION
    
    A schematic drawing of the present treatment facilities showing
    points at which feed was taken for experimental units is shown
    in Figure 9.  Activated sludge investigations were performed
    using raw equalized waste, unclarified trickling filter efflu-
    ent, and clarified trickling filter effluent in order to deter-
    mine any differences in the response of these wastes to activated
    sludge treatment.  Granular activated carbon was tested using
    both the clarified trickling filter effluent and the activated
    sludge effluent.  All trickling filter and air stripping inves-
    tigations were performed using raw equalized waste.
    
    Because the principal objective of the pilot trickling filter
    and microtower studies was to determine the effect of various
    operating modifications on the full-scale treatment system, all
    tests were conducted using equalized raw waste.  A continuous
    feed of raw waste from the equalization tanks was pumped to the
    pilot trickling system, while feed for the microtower was taken
    from the equalized raw waste sampler at 24-hr intervals.  There-
    fore, the feed to the microtower was subjected to fewer concen-
    tration fluctuations than was the pilot trickling filter system.
                                    27
    

    -------
                                                           AfTTrn—.
                                      SCREENING       SOLVENT  NEUTRALIZATION EQUALIZATION
                                                   SEPARATION
    NJ
    00
                    PILOT TRICKLING
                     FILTRATION
             MICROTOWER
             A.S = Act'vated Sludge
             A.C - Aclivaltd Carbon
                                 AERATED BASIN
    STRIPPING
             FIG. 9 .PROCESS FLOW DIAGRAM-EXISTING FULL-SCALE AND EXPERIMENTAL TREATMENT SEQUENCES
    

    -------
    The testing program with the microtower included the use of:  1)
    raw waste, 2) raw waste diluted with tap water and, 3) effluent
    recycle.  All tests in the pilot trickling filter used raw waste as
    feed to the system and effluent recycle.
    
    Activated sludge investigations were divided into three phases.
    Phase I was conducted during January and February, 1973 and had
    the objective of determining the feasibility of activated sludge
    treatment for this waste.  During Phase I investigations, tests
    were conducted using raw wastewater, unclarified trickling filter
    effluent and clarified trickling filter effluent.  Phase II investi-
    gations were conducted during the months of March, April and May
    and had the objective of determining the response of the activated
    sludge system to cold temperatures (during March and April) and
    of determining the longer term response of activated sludge
    treatment to this waste.  Based on favorable results from Phase
    I, unclarified trickling filter effluent was used for the Phase
    II investigation.  The objective of Phase III activated sludge
    investigations was to compare air and oxygen aeration for the
    treatment of this wastewater.  During this portion of the investi-
    gation, air and oxygen activated sludge units were fed unstripped
    and stripped equalized waste.
    
    During the Phase I activated sludge investigation, units were
    operated at food-to-microorganism (F/M) ratios of 0.1, 0.3, and
    0.5 g BOD/day-g MLVSS.   In the remaining portions of the study,
    the loading of all units was maintained relatively constant at an
    F/M of approximately 0.3.
    
    Activated carbon tests were conducted to determine the feasibility
    of adsorption for removing color or gross organics from both the
    trickling filter and activated sludge effluents.  Isotherm tests
    were initially made using eight different varieties of carbon.
    Based upon the results of these tests, three carbons were chosen
    for further study in column contacting systems.
    
    Air stripping investigations were conducted to determine the remov-
    als of organic constituents which could be achieved in an aerated
    basin or a packed tower.  A 13,500-gal  (51,000 liter) basin was
    constructed to simulate  an aerated equalization  basin, while one
    pilot trickling filter was used to simulate air  stripping in a
    packed  tower.  Raw equalized waste was  used as a  feed for both
    experimental investigations.  By conducting Phase  III activated
    sludge  investigations using both stripped and unstripped waste,
    effects of stripping on  the response of the waste to activated
    sludge  treatment were determined.
                                     29
    

    -------
    DATA CORRELATION
    
    Data collected in this investigation were generally correlated
    using established mathematical  models.  In trickling filter
    investigations, the model  which most closely represented experi-
    mental findings was a first-order model used by Eckenfelder (6,
    16).  Activated sludge data were correlated using the models
    which most closely conformed to those proposed by Eckenfelder
    (17, 18, 19) and Pearson (20).   The effects of temperature were
    corrected using the Streeter-Phelps model  (21).
    EXPERIMENTAL EQUIPMENT
    Pilot Trickling Filter
    
    A schematic diagram of the pilot trickling filter used in this
    study is shown in Figure 10.   This system consisted of 2 ft x
    2 ft (60 cm x 60 cm) towers containing 20 ft (6 m) of the
    Monsanto Biodize trickling filter medium.  The plastic medium
    was supported in four, 5-ft (1.5 m) sections on expanded metal
    grating.  Each tower was supported above a reservoir with a
    capacity of approximately 500 gal (2,000 liters) and was equipped
    with a forced draft ventilation system adjusted to deliver 100
    cfm (2.8 cu m/min) of air through the tower packing.  Spray
    nozzles were placed above the media in each tower at a distance
    to provide proper wetting of the media.
    
    Provision was made for piping raw equalized waste to a holding
    reservoir which was used as the influent for the system.  Raw
    waste feed to the first column was controlled using a Fisher and
    Porter flow controller.  A level controller on the reservoir
    insured that an adequate supply of feed was present at all times.
    Pumping was provided for the influent to the first tower, from
    the first to the second tower, from the second tower to the
    clarifier, and for recycle of effluent from the second tower to
    the top of the first tower.  It was possible to adjust all pumps
    to deliver flows ranging from 1 to 10 gpm (4 to 40 1 iters/min).
    Level controllers were also installed in the reservoir beneath
    each tower.
    
    The system was also provided with a 5-ft (1.5 m) clarifier.
    Sludge wasting from the clarifier was controlled by automatic
    timers.
                                   30
    

    -------
           Level
           Controller
    Flow
    Controller
    Raw
    Waste
     Overflow
               HOLDING TANK
    
    — 1 	
    1
    /K
    ' i \
    
    
    
    
    i
    -y
    0
                    Level
                    Controller
                               TOWER I
                                                                  Each  tower packed
                                                                  with 4,5- ft. sections
                                                                  of  Biodize medium
    Level
    Controller
                                  TOWER 2
                                                                                  •Effluent
                Sludge
    
               CLARIFIER
      FIG. 10. SCHEMATIC  ILLUSTRATION OF  RLOT  TRICKLING  FILTER
              (m=ftx0.3)
    

    -------
    Although nutrients were being added in the full-scale system,
    it was necessary to add more in the experimental  systems due
    to the greater quantities of BOD being removed.   Nutrient feed
    to the tower system was provided by continuously pumping a
    mixture of (NH.kSO. and Na3PO. to the reservoir beneath the
    first tower.  Because effluent recycle was practiced in all
    tests, an adequate supply of nutrients was available to biota
    in the first tower.
    
    
    Hicrotower Apparatus
    
    The microtower used in these investigations was  a laboratory-
    scale trickling filter constructed in two, 10-ft  (3 m)  sections.
    which simulated a 20-ft (6 m) plastic medium trickling  filter.
    The medium in the microtower consisted of inclined PVC  sheets
    which were designed by the manufacturer to simulate B.  F.
    Goodrich Koroseal media.  The microtower assembly along with
    auxiliary pumps and holding tanks is illustrated  in Figure 11.
    
    Equalized raw waste was fed daily into an influent tank which
    was continuously mixed to prevent settling of suspended solids.
    Following the adjustment of pH, when necessary,  and the addition
    of nutrients, this waste was fed to the microtower and  was pumped
    from the reservoir on the second tower to an effluent holding
    tank.  During effluent recycle tests, effluent was pumped from
    this barrel to the top of the first microtower section.  During
    dilution studies, the necessary dilutions were made in  the influ-
    ent feed tank.  Supplementary inorganic salts including NaCl
    and Na2$04 were added to produce a mixed TDS concentration of
    2,000 mg/1 to simulate the salts and ionic strength of  the raw
    wastewater.
    
    Daily maintenance of the microtower included adjustment of flows,
    measurement of effluent volumes, correction of uneven flow dis-
    tribution pattern through the filter, and cleaning of the influ-
    ent and effluent drums.  Routine analyses included pH and TSC
    daily on influent and effluent samples.  When the tower was
    acclimated to a particular operating condition as judged by
    consistent TSC measurements, additional samples were taken.
    Under stabilized operating conditions for each run, the fol-
    lowing data were collected at five points through the depth of
    the microtower:  pH, temperature, TSC, COD, BOD,  and dissolved
    oxygen.  In addition, oxygen uptake rates of the  slime  were
    determined at these points in the filter.  The oxygen uptake
    procedure used for this investigation is described in a separate
    section below.
                                   32
    

    -------
                                                 Mixing Unit
    to
                      EQUALIZATION
                                   INFLUENT
                                    TANK
    MICROTOWER
                                                                        Flow
                                                                        Distributor
                                                                        Media Segment Approx.
                                                                        2 ft long
                                                                                         Bi
                                                                                         
    -------
    Activated Sludge Units
    
    Continuous-flow activated sludge units were fabricated from 55-
    gal  (200 liter) drums and had a 40-gal (151 liter) capacity.  A
    schematic illustration of these units is shown in Figure 12.
    Units were constructed by welding a baffle into the side of each
    drum which served as a clarification section.   Three-quarter inch
    (2 cm) nipples welded through the side of each barrel  permitted
    the maintenance of a constant level in the aeration basin and
    allowed effluent to overflow into containers provided  for this
    purpose.  Diffused air aeration was supplied through 12-in. (30
    cm) porous stone diffusers.   These diffusers were suspended in
    the tank to provide adequate mixing of the mixed liquor solids,
    to maintain desired oxygen levels and to prevent turbulence in
    the clarifier section.
    
    The feed to the units was provided through a variable-speed tube
    pump.  Effluent, collected from various points in the  treatment
    plant, was collected daily and added to feed drums.   Effluent
    was collected in containers  provided for each unit and the efflu-
    ent volume was measured daily.  Nitrogen and phosphorus were
    added daily to the waste feed tanks in order to provide a BOD:
    N:P ratio of 100:5:1.  When  required, the pH of the influent
    waste was adjusted to approximately pH 7.   When necessary, mixed
    liquor was wasted from the units in order to provide an operating
    MLVSS level of 2,500 mg/1.   After sludge was wasted, effluent
    collected during the previous 24-hr period was added to make up
    the lost volume in the aeration basin.
    
    Operation of the activated sludge units was initiated  by using an
    equal mixture of sludge obtained from the Cranston,  Rhode Island
    municipal activated sludge plant and clarifier sludge  from the
    CIBA-GEIGY trickling filter system.  Operation of the  units was
    begun the first of December, 1972.   Approximately five weeks were
    required for complete acclimation of the biological  solids to
    this waste.
    
    Flow to the units was adjusted daily in order to maintain the
    desired F/M ratios for each  unit.   Upon occasion it  was necessary
    to adjust the pH of the aeration basin by adding 50 percent NaOH.
    In addition it was frequently necessary to add a silicone defoam-
    ing agent to the aeration basin to suppress frothing.
    
    The influent, effluent, and  contents of the aeration basin were
    sampled daily.  Analyses which were made on the influent and
                                   34
    

    -------
    UJ
                    Waste     ^-^—
                    Feed    —(- )
                    Drum      X-A
                    Compressed
                    Air Supply
                         Air
                         Stone
                                                 TC,
    \
                                        Baffle
                                      55-gal. drum
                                                   \
                   Overflow
                   Pipe
    Effluent
     Drum
                                        Activated
                                       Sludge Unit
    
          FIG. 12.  SCHEMATIC ILLUSTRATION OF ACTIVATED  SLUDGE  UNITS
                  (Liters = gal x 3.8)
    

    -------
    effluent samples daily included pH, TSC, and suspended and volatile
    suspended solids.  These samples were analyzed three times per week
    for total and soluble BOD and COD.
    
    Contents of the aeration basin were analyzed daily for total  and vola-
    tile mixed liquor suspended solids  and pH.   These samples were analy-
    zed four times per week for oxygen  uptake rate, zone settling velo-
    city, and sludge volume index.  Weekly samples were taken for total
    kjeldahl nitrogen and total phosphorus measurements.  Occasionally,
    samples were analyzed for solvents.
    
    During Phase I investigations, activated sludge units were operated
    indoors at a waste temperature of approximately 17°C.  During Phase
    II investigations, one unit was moved outside in order to determine
    the effect of temperature on activated sludge performance.  In Phase
    III investigations, all units were  moved outdoors where the tempera-
    ture varied from approximately 20 to 24°C.
    
    During the Phase III activated sludge investigations, two units were
    modified for use as oxygen activated sludge units.  A schematic
    illustration of these units is shown in Figure 13.  Modification of
    these units essentially consisted of adding a sealed cover to each
    unit so that an oxygen-rich atmosphere could be maintained above
    the liquid.  Additional piping in the covers for these units was
    provided to allow for the introduction of oxygen, withdrawal of off-
    gases, recirculation of gas to the  mixed liquor, and introduction of
    feed to the unit.  A gas compressor was piped into each unit to pro-
    vide a constant diffused air supply for the mixed liquor.  These
    compressors had a capacity of approximately 1 scfm (0.03 cu m/min)
    and were adequate to maintain proper mixing and dissolved oxygen
    levels in the mixed liquor.  Additional piping was added to allow
    the withdrawal and introduction of  mixed liquor samples for daily
    testing.
    
    Oxygen feed to the units was supplied from gas cylinders.  Influent
    oxygen flow was controlled using a  stainless steel metering valve
    and was monitored using gas rotometers.  Off-gas measurement was
    accomplished using wet test meters.  Operational procedures for the
    oxygen activated sludge units were  essentially the same as those
    followed for air activated sludge.
    
    
    Activated Carbon Tests
    
    Carbon Isotherms.  Batch adsorption tests were conducted by con-
    tacting waste samples and granular  activated carbon in a wrist-action
                                      36
    

    -------
             Waste
             Feed
             Drum
                Oxygen
                Supply
                   Sample
                    Port
                                Activated
                               Sludge Unit
    FIG.I3. SCHEMATIC ILLUSTRATION OF OXYGEN  ACTIVATED  SLUDGE
           UNITS
           (Liters = gal x 3.8)
    

    -------
    laboratory shaker for a 24-hr period.   Although powdered carbon
    is frequently used for isotherm tests, results using the granular
    carbon are more representative since waste constituents must
    diffuse through pores in the carbon particles before being ad-
    sorbed onto the carbon.  Granular carbon was sieved to obtain
    the desired range of particle sizes, soaked in distilled water
    for 24 hr, oven dried at 103°C for 24 hr, and cooled in a dessi-
    cator.  Varying amounts of carbon were added to each test flask,
    and then contacted for 24 hr with 200 ml of waste which had been
    previously filtered through Reeve Angel  Grade 802 filter paper.
    Usually carbon was added to obtain COD to carbon ratios ranging
    from 0.05 to 5.0 g/g.
    
    After 24 hr the waste-carbon mixture was filtered through GF/C
    glass fiber filter paper to separate the carbon from the waste.
    A control sample was subjected to the same test procedure as
    each carbon sample.  Initial tests conducted using varying con-
    tact times determined that the 24-hr period would be sufficient
    for all practical purposes to obtain equilibrium between the
    carbon and wastewater.
    Column Units.   One carbon column unit was fabricated from 1-in.
    (2.54 cm) Pyrex glass tubes and is illustrated in Figure 14.   Feed
    to these columns was provided using a tube pump.   Columns were
    operated upflow with each column containing approximately 3 cm
    of glass beads supporting 60 cm of activated carbon.  The columns
    were operated at a flow rate of 2.5 gpm/sq ft (0.1  cu m/min-sq m).
    Clamps were provided at the top of each column so that each carbon
    bed could be backwashed individually.  Solids accumulation made it
    necessary to backwash each column daily.   Grab samples were col-
    lected daily from the influent and effluent from  each column.
    Daily analyses were made for TSC, suspended solids, turbidity, and
    color.  In addition, samples were analyzed twice  per week for BOD
    and COD.
    
    A set of four, 4-in. plexiglass columns were used for testing ad-
    sorption of the trickling filter effluent.  Feed  for these columns
    was provided by constantly pumping clarifier effluent from the
    full-scale treatment system into the control  building.   Waste was
    pumped through the columns at a rate of 5 gpm/sq  ft.  Grab samples
    of the influent waste and the effluent from each  column were taken
    periodically and analyzed for COD, BOD, TSC, color and suspended
    solids.  Columns were backwashed as necessary to  prevent excessive
    headloss.
                                    38
    

    -------
    u>
                             FULL SCALE
                             TRICKLING
                              FILTERS
    PILOT ACTIVATED
    SLUDGE UNITS
    
    
     F/M • 0.3 -0.5
                                               Screw
                                               Clamps
                      2.5 cm Pyrex
                          pipe
                                              170 g
                                              Carbon
                                            Glass
                                             Beads
                                                     PUMP
                                                    to
                                                                                   -14-
                                                                                V
                                HOLDING TANK    SAMPLING POINTS                    EFFLUENT TANK
    
    
               FIG. 14. SCHEMATIC  ILLUSTRATION OF ACTIVATED CARBON COLUMNS
    

    -------
    Packed Stripping Tower
    
    The removal  of organic constituents which could be achieved by air
    stripping in a packed tower was investigated by converting the
    first pilot trickling filter for this purpose.   Necessary modifi-
    cations included the installation of a 2,500 cfm (70 cu m/min)
    blower into the side of the reservoir of the tower and the addition
    of a 40-gpm (151 liter/min) pump to supply influent to the top of
    the tower.   The influent pump was piped to receive the equalized
    raw waste flow in the influent reservoir for the pilot trickling
    filter system.
    
    Influent and effluent samples were collected during each run and
    analyzed for BOD, COD, and suspended solids.  In addition, occa-
    sional samples were analyzed for solvent concentrations.
    Aerated Equalization Basin
    
    Because of the possibility of adding additional  equalization capa-
    city to the treatment plant, the feasibility of achieving removal
    of organic constituents by air stripping in an aerated basin was
    investigated.  For this purpose a 24-ft (7.3 m)  diameter, 5-ft
    (1.5 m) deep swimming pool was constructed at the treatment fa-
    cility.  The basin was designed for a water depth of 4 ft (1.3 m)
    and had a resulting capacity of 13,500 gal (51,000 liters).
    Aeration was provided by a 2-hp (1.5 kw) aerator (Mixing Equipment
    Comi.,-ny, Rochester, N. Y.).  This corresponded to a power level of
    150 hp/mil gal (0.03 kw/cu m).  Influent to the basin was provided
    from the equalization basin.  An inverted U-tube located at the
    outlet of the basin was used to maintain a liquid level of 4 ft
    (1.2 m).  Samples of the basin influent and effluent were taken
    daily and analyzed for BOD, COD, and suspended solids.  An illus-
    tration of this basin is shown in Figure 15.
    SAMPLING AND ANALYTICAL METHODS
    
    Analytical methods used during the course of this investigation
    conformed to those prescribed in Standard Methods for the Examina-
    tion of Hater and Mastewater (13th edition).The graduate dilution
    method was used for BOD analyses except in a few cases when time
    dictated that the pipetting method be used.  Soluble BOD and COD
    determinations were made by filtering samples through glass fiber
    (GF/C) filter paper.
                                    40
    

    -------
                                                       Effluent
      Influent
      Woste
                               C_—- 2 h.p. Aerator
                        24 ft dia. x 4 ft. deep
                        basin - Vol. = 13,500 gal
                           TOP VIEW
                                                         Steel
                                                         Support
                                                          Concrete
                                                          Foundation
                              SIDE VIEW
    FIG. 15. AERATED  EQUALIZATION  AND  STRIPPING
            BASIN
            (m = ft x0.3,kw = hpx 0.77, cu m =galx 0.004)
                                  41
    

    -------
    Total carbon analyses were initially made using an Ionics total
    carbon analyzer and later using a Beckman Model 915 analyzer.
    Tests were made to insure that identical results were obtained
    using both instruments.  Inorganic carbon analyses determined
    from raw waste samples at the beginning of the investigation
    showed that an average of approximately 5 mg/1 were present.
    Therefore, in subsequent analyses, except as noted, only total
    carbon determinations were made.   Based on recommendations of
    the manufacturer of the total carbon analyzer, all samples were
    filtered through Whatman No.  2 paper prior to analysis.  For
    consistency total carbon values determined in this investiga-
    tion are referred to as total soluble carbon, TSC.  For this
    waste the variation between TSC and total  organic carbon (TOC)
    was approximately 0.5 percent for the untreated wastewater.
    Solvent concentrations were determined using gas chromatographic
    procedures employed in the CIBA-GEIGY analytical laboratory.
    Because the oxygen uptake and zone settling velocity tests are
    not described in Standard Methods, these tests are described in
    detail separately.
    Oxygen Uptake Test
    
    The oxygen uptake rate was measured by placing mixed liquor from
    the aeration chamber in a BOD bottle.  A dissolved oxygen probe
    was inserted, insuring that no air bubbles were trapped inside,
    and the mixer turned on to maintain the contents of the bottle
    in suspension.
    
    Oxygen uptake measurements in the trickling filter systems were
    made by taking plastic medium patches and immersing them in
    waste samples taken at the same depth in the filter system.
    The decrease of oxygen in the waste was recorded using a dis-
    solved oxygen probe and chart recorder.  The results were re-
    corded as milligrams of oxygen used per square centimeter of
    plastic medium per hour.   For the microtower system, patches
    cut from the medium were placed in the microtower at 4, 8, 14,
    and 16-ft (1.2,  2.4, 4.3, 4.9 m) depths.   In order to determine
    the oxygen uptake rates of the biological slime, the patch was
    removed from the tower and scraped free of siime except for a
    3-in.  x 3-in.  (7.6 cm x 7.6 cm) area of active slime.  Subse-
    quently,  the patch was placed in a closed 1-liter container
                                    42
    

    -------
    filled with waste and the oxygen depletion recorded with time.
    Patches were located in the microtower so that they could be
    replaced after each determination.
    
    To make oxygen uptake determinations in the full-scale trick-
    ling filter system, a 5-in. x 5 3/4-in. (13 cm x 15 cm)
    piece of plastic medium was cut from a larger section located
    at mid-depth in each tower.  Care was taken to obtain sample
    patches located far enough into the tower to receive a repre-
    sentative portion of waste flow.
    Zone Settling Velocity
    
    The zone settling velocity test  (ZSV) expresses the rate of
    interface settling of particular sludqe in ft/hr (m/hr).  The
    ZSV test is conducted by filling a 1,000-ml cylinder with mixed
    liquor suspended solids from the aeration chamber.  The con-
    tents were slowly stirred with a mechanical device at a speed
    of 4-6 revolutions/hr.  This stirring was used to break up the
    bridging of the sludge in the small-diameter cylinders.  As
    the sludge settled, the interface was recorded at selected
    time intervals.  The interface level was plotted against set-
    tling time and the zone settling velocity calculated from the
    slope of the straight line portion of the curve.
                                     43
    

    -------
                               SECTION VI
    
               SMALL-SCALE TRICKLING FILTER INVESTIGATIONS
     Investigations in small-scale trickling filter systems were under-
     taken to examine and verify BOD removal mechanisms which were
     occurring in the full-scale filter system, and to determine the
     effects of recycle on filter performance.   Tests were made both
     with a single-stage microtower operated in the laboratory and
     a two-stage plastia,medium pilot trickling filter.  Investiga-
     tions were conducted using the microtowers in order to gain
     increased operating flexibility compared to the pilot system.
    MICROTOWER TESTS
    
    Equalized raw wastewater, collected continuously from the influ-
    ent to the full-scale system, was fed daily to the microtower.
    Investigations in the microtower system consisted of three parts:
    1) tests using a raw waste feed, 2) tests using a raw waste feed
    diluted with 0.5, 1, or 2 parts of tap water, and 3) tests in
    which filter effluent was recycled along with raw waste.   Remov-
    able sections of plastic packing were placed into the microtower
    at several depths in order that oxygen uptake determinations
    could be easily made.
    Effect of Variations in Organic Loading
    
    A range of raw waste flows varying from 0.66 to 3.10 gpm/sq ft
    (0.03 to 0.13 cu m/min-sq m) was applied to the filter in order
    to study its response to varying concentrations and organic load-
    ings.  The influent COD concentration for these tests varied
    between approximately 4,000 and 6,600 mg/1.  The corresponding
    organic loading varied between approximately 1,000 and 13,000
    Ib COD/day-1,000 cu ft (16 and 200 kg COD/day-cu m).  In dilution
    studies, raw waste feed was diluted with 0.5 to 2.0 parts of tap
    water.  Applied organic loadings in these tests varied from
    approximately 1,000 to 6,000 Ib COD/day-1,000 cu ft (16 to 96
    kg COD/day-cu m) with applied COD concentrations ranging from
    approximately 750 to 2,400 mg/1 COD.   Hydraulic application rates
    for the dilution tests were either 1.4 or 2.1 gpm/sq ft (0.06 or
    0.09 cu m/min-sq m).  Thus, in these tests the applied COD con-
    centration for corresponding loading rates (Ib COD applied/day-
    1,000 cu ft or kg COD applied/day-cu m) was significantly lower
                                   44
    

    -------
    compared to tests in which undiluted raw waste was applied to the
    filter.  The results of these tests, shown in Figure 16, reveal
    that significantly greater percentage COD removals were obtained
    at corresponding organic loadings when the undiluted raw waste
    was applied to the filter.   Differences in performance might be
    due to either differences in hydraulic loading or to the concen-
    tration differences.   It is  felt that concentration differences
    largely explain the difference  in performance due to reduced
    removals by air stripping at the lower applied concentrations.
    
    In the effluent recycle studies, hydraulic loadings applied to
    the filter ranged from 1.9 to 2.8 gpm/sq ft  (0.08 to 0.11 cu
    m/min-sq m).  The COD  removal efficiency for these tests, shown
    as a function of applied organic loading,  is illustrated in
    Figure 17.  In this case, the removal was calculated based on
    the organic concentration of the raw wastestream.  It can be
    seen that organic removals obtained using effluent recycle are
    much greater for low organic loadings than was obtained in other
    tests.  The higher removals  obtained at low  organic loadings
    corresponded to the highest  recycle ratios.
    
    These  results show that optimum conditions for biological
    activity in the trickling filter may be produced by recycling
    effluent.  On the other hand, changes in operational conditions
    to optimize biological  activity in the filters also result in
    a decrease in the effectiveness of the other principal BOD
    removal mechanism, i.e. air  stripping.  The  results in Figure
    18 show that increasing the  recirculation ratio to approx-
    mately six greatly increased removals which  can be achieved
    in the trickling filter.  However, increasing the recycle
    ratios above six had very little additional  effect on the
    improvement of removal  efficiency.
     Oxygen  Uptake  Measurements
    
     The oxygen  uptake  rate  is  illustrated  as  a  function  of applied
     organic  load in  Figure  19.   These  data show that  oxygen use  in
     the raw  waste  tests  increased  slightly with applied  organic  load,
     but that the absolute values were  significantly  lower than in the
     dilution and recycle studies.   Oxygen  utilization in dilution
     tests was relatively constant  over the range of  loadings applied.
     In effluent recycle  tests,  oxygen  utilization was highest at  low
                                     45
    

    -------
       60
       40
    LJ
    tr
    
    §  20
        0
         0
                            -Raw Waste Tests
                            Dilution Tests
    2000     4000    6000    8000     10,000    12,000    14,000
         ORGANIC LOADING (Ib COD/day-IOOO cu ft)
      FIG. 16 .VARIATION OF REMOVAL  EFFLUENT  WITH  APPLIED COD
             LOAD
         (kg/cu m-day =lb/IOOO cu ft-day x 0.016)
    

    -------
       100
    
    
       80
    
    
       60
    
    
    5  40
    
    O  20
         LU
         CE
    
         Q
         O
         O
    
         CC
         O
    
         Q
         O
         CD
        0
         0
       100
    
    
       80
    
    
       60
    
    
       40
    
    
       20
              0
                                               COD data
                             BOD  data
    1000   2000  3000  4000   5000   6000  7000
              0      1000    2000    3000    4000    5000   6000
                   APPLIED ORGANIC LOAD (Ib/day-IOOO cuft)
    
    FIG. 17 .REMOVAL EFFICIENCY VERSUS APPLIED ORGANIC LOADING
           IN THE RECIRCULATION STUDY
       (kg/cu m-day = lb/IOOO cu ft-day x 0.016)
    

    -------
          a>
          CO
           ,co
          CO
           o
    
           LJ
           tr
    
           o
           o
           0
    
           o:
           o
    
           Q
           o
           CD
                                               BOD data
    
                                           Raw Waste Flow = 0.3-1.7
                                                    gpm/sq fl
               0
                0
    3456
    
     RECYCLE RATIO, N
    FIG. 18 .BOD AND COD REMOVAL EFFICIENCY VERSUS RECYCLE
           RATIO
    

    -------
               2000
      4000      6000      8000      IQOOO
    ORGANIC LOADING (Ib COD/day-1000 cu ft)
    12,000
    14,000
    FIG. 19 .EFFECTS OF ORGANIC LOADING ON OXYGEN UPTAKE RATE
     (kg/cu m-day = lb/IOOO cu ft-day x 0.016)
    

    -------
    organic loadings due to increased biological  activity.   Total
    oxygen uptake is shown as a function of the recycle ratio in
    Figure 20.   These data show that oxygen use increased with
    increasing  dilution of the influent waste, but decreased at
    very high recycle ratios probably due to the  significant de-
    crease in organic loading.
    
    Oxygen utilization shown as a function of the quantity of COD
    removed in  Figure 21 was used to determine oxygen utilization
    coefficients.  The data in this figure were divided into
    three separate parts:   1) raw waste tests, 2) dilution  tests
    having a dilution ratio of 0.5 to 2 and recycle tests having
    recycle ratios ranging from 0.2 to 1.9, and 3) recycle tests
    having recycle ratios  ranging from 2.8 to 8.4.  The slope of
    the line defined by each set of data yields the oxygen utili-
    zation per gram of COD removed.  The data show that signifi-
    cantly higher quantities of oxygen were used  per gram of COD
    removed as  the dilution of the influent waste increased.  The
    value for a'  of 0.6 g  02/g COD removed in the recycle studies
    was almost  identical to the oxygen utilization value of 0.67
    g 02/g COD removed measured in activated sludge investigations
    using air aeration.  The ordinate intercept of each line in
    this figure defines the endogenous oxygen requirement for
    microorganisms under each operating condition.  These data
    indicate that the endogenous activity of the  microorganisms is
    inhibited by high organic loading rates.  This phenomenon is
    probably the result of the high concentrations or organic con-
    stituents at low waste dilution ratios.
    
    Using the oxygen utilization coefficient obtained in Figure 21,
    it was possible to estimate the quantity of COD removed biologi-
    cally from oxygen uptake data.  Removals of COD from oxygen uptake
    data were calculated according to the following relationship:
    
                          (SJ  = (A0? - b')/a'
                            r B      c
    
        where (S )   =  COD removed biologically  (g/sq cm-day)
                r B
             A02    =  total oxygen uptake (g 0?/sq cm-day)
    
              b'      =  auto-oxidation uptake (g  02/sq cm-day)
    
             a'      =  oxygen utilization coefficient (g 0,,/g
                        COD removed)                    "   
    -------
       0.40
    I  0.30
    
    CT
    (0
    £
    
    LJ
       0.20
    Q_
    LJ
    O
    
    X
    o
    0.10
         0
          0
                                                  8
         I     234567
    
                        RECYCLE RATIO, N
    
    
    FIG.20.OXYGEN UPTAKE VERSUS RECIRCULATION RATIO
    10
    

    -------
    Cn
    K5
                      0.40
                   7: o.3o
                 CM
                o
      o
    
      CT
      to
                  UJ
                  CO
                  ID
    UJ
    CD
    
    X
    O
        0.20
                      0.10
                        0
                                 Recycle N=2.8-8.44
                                                          •  Raw Waste Tests
                                                          A  Dilution Tests
    
                                                          O  Recycle Tests
                                         Dilution N = 0.5-2.0
                                         Recycle N = 0.2 - 1.93
                            Autooxidation
                            Uptake
                          0
                                                                   Raw Waste
                                i.o                 2.0
                          COD REMOVED (g CODr/sq cm-hr)
    3.0
                         FIG.21  .OXYGEN  UTILIZATION IN THE MICROTOWER
    

    -------
    The calculated COD removed according to oxygen uptake data  (SrOn
    is compared to the measured COD  removal,  (Sr)T, as a function   B'
    of the applied COD concentration, Sa,  in  Figure 22.  These data
    show that the fraction of COD removal  accounted for by biological
    mechanisms increased significantly as  the applied COD concentration
    to the filter decreased.  At high applied COD concentrations these
    data indicate that only approximately  10  percent COD removal
    was due to biological mechanisms.  For high  influent COD
    concentrations, this value was significantly lower than that esti-
    mated for the full-scale treatment system.   However, the results
    for the microtower were obtained from  a single-stage trickling
    filter system, while oxygen uptake values discussed for full-scale
    system were total values for all six stages.
    
    
    PILOT TRICKLING FILTER INVESTIGATIONS
    
    A two-stage pilot trickling filter consisting of two 20-ft (6 m)
    towers having cross-sectional areas of 4  sq ft (1.4 sq m) were
    constructed to determine the effect of certain operational  changes
    on the full-scale trickling filter system.  The objective of these
    investigations was to determine the operating characteristics of
    the pilot system at various recirculation ratios and to determine
    the degree of BOD removal by air stripping occurring in the first
    part of the full-scale system.  The pilot trickling filter was
    constructed so that equalized raw waste from the riser to the
    first tower of the full-scale system could be used as feed for the
    pilot system.  Considerable difficulty was experienced in generat-
    ing an adequate biological slime in these towers.  Growth in the
    pilot system was very similar to the small amount of growth ob-
    served in the full-scale system.  However, no difficulty was en-
    countered in obtaining an adequate growth of microorganisms in
    the microtower.  The difference might  have been due either to the
    lesser degree of equalization provided in the pilot and full-scale
    systems or to differences in the characteristics of the plastic
    medium used.  Pieces of wood placed at mid-depth in the second
    pilot tower showed a somewhat greater  growth of slime than did
    the plastic medium, but the growth was still less luxuriant than
    would be expected for the organic loading rates which were used
    in this system.  During the months of  July and August, it appeared
    that the maximum amount of growth obtainable had been generated
    into pilot systems.  Therefore,  biological studies were initiated
    at that time.  Prior to growing  a biological slime  in the pilot
    system, removals across the  two  pilot  towers were monitored
                                    53
    

    -------
           1.0
    CL
    or
    to
    p
    LJ
    m
    0.8
    0.6
    §
    LJ
    a:
    o
    o
           0.4
    0.2
            0
             0
                                                •  Raw Waste Tests
    
                                                O  Recycle Tests
    
                                                A  Dilution Tests
             1000    2000    3000    4000    5000    6000
                    APPLIED  COD CONCENTRATION, Sa (mg/l)
    7000
     FIG.22. FRACTION OF COD REMOVAL DUE TO OXYGEN UPTAKE  IN
             THE MICROTOWER
    

    -------
    in order to determine the amount of stripping occurring in the
    first part of the full-scale system.  The results of these investi-
    gations are shown in Table 3.  The average removal achieved over this
    period was significantly greater for Tower 1 than Tower 2 indicating
    that most volatile substances were removed through the first tower,
    while additional volatile materials were removed in the second
    tower, but to a lesser degree.  Total carbon removals averaged
    9.6 and 4.7 percent for Towers 1 and 2, respectively.  Corresponding
    total carbon removals for days on which data were available for
    both the pilot and full-scale systems were 6.8 and 7.1 percent for
    the pilot system and 6.8 and 7.7 percent for the first two towers
    in the full-scale system.  These data indicate that practically
    all removal of COD in the first two towers was due to the air
    stripping mechanisms.
    
    Recycle investigations in the single-stage microtower indicated
    that approximately 85 to 90 percent BOD removal could be achieved
    at recycle ratios greater than 6.0.  While this degree of recycle
    would not be possible in the full-scale system, further tests
    in the pilot towers were undertaken to determine removals which
    could be obtained with recycle ratios ranging between 1.0 and 3.0.
    The effect of recycle on COD removal in the pilot filter system
    is shown in Figure 23.  The recycle data indicate that the per-
    formance of the full-scale trickling filter could be improved by
    adding recycle capabilities.  Organic loading rates to the first
    tower for data shown in this figure were 915, 984, 770, and 152
    Ib COD/day-1,000 cu ft (1.47, 1.58, 1.23 and 0.24 kg COD/day-cu m)
    for recycle ratios of 1.0, 1.4, 1.67, and 3.0, respectively.
    
    Because the strength of waste was somewhat lower than average
    during the period of these studies, organic loads applied to the
    filters were less than would be anticipated for the full-scale
    treatment facility.  The variation of COD removal with organic
    loading is presented in Figure 24.  These results show that the
    major fraction of COD removal occurred through the first tower
    indicating that the rate of degradation will decrease through the
    system.  This might be due to stripping effects or to the removal
    of more readily degradable substances in the first tower.
                                     55
    

    -------
                        TABLE  3
    
    
    
    STRIPPING RESULTS  FROM PILOT  TRICKLING  FILTER
    Date
    (1973)
    3/12
    3/14
    3/15
    3/16
    3/20
    3/21
    3/23
    3/24
    3/29
    3/3,
    4/2
    14/3
    Average
    COD (niq/1)
    Influent
    -
    6720
    -
    5920
    -
    4200
    3460
    -
    5040
    2940
    Tower 1 Eff.
    -
    5720
    -
    5670
    -
    3400
    3840
    -
    4640
    2240
    Tower 2 Eff.
    -
    5080
    -
    4800
    -
    3800
    5080
    -
    4520
    2280
    TSC (ma/1)
    Influent
    1450
    1850
    1640
    1530
    875
    1115
    -
    1325
    1140
    1160
    750
    975
    Tower 1 Eff.
    1300
    1690
    1420
    1600
    450
    1025
    -
    1160
    1140
    1090
    650
    950
    Tower 2 Fff
    1230
    1500
    1420
    1295
    470
    1090
    -
    1185
    1115
    1115
    600
    875
    11.9* 6.4* 9.6% 4.7%
                            56
    

    -------
       100
       80
      < 60
    
      o
      UJ
       40
      Q
      O
      o
        20
        0
          0
                   A I Tower
    
                   • 2 Towers in series
    1.0             2.0
    
     RECYCLE  RATIO, N
    3.0
    FIG.23.EFFECT OF RECYCLE ON PILOT TRICKLING FILTER
           PERFORMANCE
    

    -------
    Ul
    00
               100
                80
              S60
              o
              LJ
              CC
    
              Q
              O
              O
    20
                0
                 0
                 500         1,000
    
                     COD LOADING (
    1,500
    2,000
                                                Ib
                                            1,000 cu f t-day
        FIG.24. VARIATION OF PILOT TRICKLING FILTER PERFORMANCE
                AND ORGANIC LOADING
                (kg/cu m-day = lb/1000 cu ft-day x 0.016)
    

    -------
                              SECTION VII
    
               FULL-SCALE TRICKLING FILTER  INVESTIGATIONS
    
    
    Performance of the present trickling filter facility was monitored
    for a nine-month period beginning in November, 1972.  Following
    modification of the system to provide effluent recycle, additional
    tests were made during April and May, 1974.  In addition to daily
    measures of plant operations and treatment efficiency, data were
    collected to determine organic carbon removals and oxygen availa-
    bility in each of the six trickling filter stages.  Additional
    data taken to provide further insight regarding system behavior
    included oxygen uptake rates using biota from the trickling filter
    and analysis for individual substances  present in the wastestream.
    From November, 1972 through May, 1973 all raw equalized waste and
    trickling filter effluent samples were  composited continuously over
    24-hr periods.  During June'and July, 1973 increased biological
    activity in the waste due to higher temperatures made it advisable
    to implement another sampling procedure.  Over this time, four
    grab samples were taken during each 24-hr period and composited for
    one daily sample.  While some samples of waste from individual
    towers were taken continuously over a 24-hr period, most analyses
    were made from grab samples taken on the morning of the day on
    which analyses were performed.
    
    Due to several upsets in the neutralization system during the months
    of December and January, the trickling  filters were reseeded twice
    during February using mixed liquor from a nearby municipal activated
    sludge plant.  This procedure was undertaken to insure as uniform
    a growth of biota as possible for subsequent studies.  However, after
    reseeding the system, no definite beneficial effects were observed.
    In February, 1973, a batch equalization procedure was implemented to
    assure greater control over the influent waste pH.  Beginning in
    March, 1973, only one pH upset occurred during the subsequent five-
    month period.
    
    This chapter contains all data concerning the operation of the full-
    scale treatment facility along with an  interpretation of the findings
    as they pertain to the upgrading of the system to meet anticipated
    regulatory requirements.  A summary of  operational data is presented
    in Appendix B.
                                     59
    

    -------
     ORGANIC REMOVAL PERFORMANCE
     Variation of Organic Loading and Removal Efficiency
    
     Due to variation in waste organic strength, applied flow rate, and
     seasonal temperatures, several fluctuations in trickling filter
     performance were observed during the course of the investigation.
     The chronological variation of BOD removal in the treatment system
     over  this period is presented in Figure 25.  Performance of the
     system averaged for monthly periods beginning in November, 1972
     are shown in Table 4.  While it appeared during March and April
     that  a significant improvement in trickling filter performance
     would be realized in warmer weather, the results for May and June
     show  that another factor significantly reduced removals for these
     two months.  Data presented in Figure 25 indicate that the in-
     creased BOD reductions (judged on a percentage basis) observed
     during March and April were due to the decreased influent waste
     load, since the quantity of BOD removed remained at approximately
     100 lb/1,000 cu ft-day for January through June.  Following that
     time, 200 gpm  (0.75 cu m/min) of cooling water was removed from
     the plant process wastestream resulting in increased BOD concen-
     trations beginning the last half of June.  Organic loadings ap-
     plied to the filter system (Ib BOD/day-1,000 cu ft or kg BOD/
     day-cu m) were higher than average during June and July due to
     intensive production schedules.
    
     During February, March, and April, investigations were also under-
     taken to determine the performance of the system at reduced loading
     rates.  Therefore, during March and April, changes were made in
     several variables which are expected to have a positive effect on
     treatment plant performance.   These included:   1) a decrease in
     the influent BOD concentration, 2) a decrease in the applied hy-
     draulic and organic loadings,  and 3) an increase in temperature.
     While it is not possible to precisely identify the effect of these
     changes on system performance, it appeared that decreases in hy-
     draulic loading did not produce significant improvements in system
     performance.
    
     The relationship of applied BOD load to the quantity removed at
     various hydraulic loading rates is illustrated in Figure 26.   A
     line which best fits  these data indicates  that an average of 33
    percent BOD was removed in the system.   These  data  also indicate
    that increasing quantities of  BOD were  removed at organic loading
                                     60
    

    -------
       100
    
    
    ~ 80
    
    _j
    ^ 60
    UJ
    oc
       40
       20
        0
               i     i
                                     1	1	r
         IN   12-3  12-31  1-28   2-24  3-25 4-22  5-20 6-17   7-15 7-29
                                TIME (weeks)
         l-l   12-3  12-31  1-28  2-24  3-25 4-22 5-20  6-17  7-15 7-29
                               TIME (weeks)
    
    
      FIG. 25 .CHRONOLOGICAL VARIATION  OF  BOD REMOVAL
          (kg/cum-day = lb/IOOOcu ft-day x 0.016)
                                 61
    

    -------
                                                                         TABLE  4
    
                                                          MONTHLY TRICKLING FILTER  PERFORMANCE
    Date
    (1972-73)
    Nov
    Dec
    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    
    BOD (mg/1 }
    Inf
    Total
    3300
    4600
    3204
    3574
    3002
    1577
    1735
    3059
    4345
    
    Eff
    Total
    -
    3538
    2557
    2642
    1731
    805
    1147
    2365
    2537
    
    SoT
    -
    Rema
    (i)
    -
    3310 '23.1
    2098
    2548
    1566
    619
    1054
    2728
    2287
    
    20.2
    26.1
    42.3
    49.0
    33.9
    22.7
    41.6
    
    COD (mg/1 )
    Inf
    Total
    4279
    5240
    5316
    5012
    4449
    3002
    2869
    5029
    6333
    
    Eff
    Total
    2844
    4278
    4142
    3637
    2741
    1695
    2219
    3870
    3881
    
    Sol
    2841
    3549
    3764
    3279
    2301
    1368
    2026
    3576
    3578
    
    Rema
    (*)
    33.5
    18.4
    22.T
    27.4
    38.4
    43.5
    22.6
    23.0
    38.7
    
    TSC (mg/1)
    Inf
    Total
    1115
    1586
    1402
    1407
    1257
    828
    800
    1225
    1376
    
    Eff
    Total
    -
    -
    -
    -
    -
    -
    -
    -
    _
    Sol
    853
    1244
    1143
    1186
    810
    493
    663
    948
    1011
    I
    Rem
    (*)
    23.5
    21.6
    18.5
    15.7
    35.6
    40.5
    17.1
    22.6
    26.5
    
    Temperature
    (#)
    Inf
    63
    62
    58
    59
    62
    65
    70
    88
    73
    
    Eff
    59
    58
    55
    54
    60
    63
    64
    71
    81
    
    Air
    41
    34
    31
    31
    43
    49
    57
    68
    78
    
    Avg
    Flow .
    (mad)0'
    1.13
    1.05
    1 .19
    0.87
    0.56
    0.89
    0.99
    0.95
    1 .0
    
    1
    System Loading1" i
    (Ib organic/
    1000 cu'ft-day)
    BOD
    518
    671
    530
    432
    223
    195
    239
    404
    604
    
    COD
    627 1
    765
    879
    606
    346
    371
    395
    664
    880
    
     Based on total influent and effluent values.
     Flow in cu m/day = mgd x 3.7.
    cLoading to first filter is 6 times these values:  loading in kg/cu m-day = lb/1000 cu ft-day x 0.016.
    

    -------
       400
    CD
      3300
       •200 -
     §
     o
    
     UJ
     
    -------
    rates as high as approximately 750 Ib BOD/day-1,000 cu ft (12
    kg BOD/day-cu m).  While the BOD load applied to these filters
    ranged higher than usually employed, the quantity of BOD re-
    moved was significantly lower than expected.  For readily de-
    gradable wastes, approximately 80 to 90 percent BOD removal
    would be expected for loadings ranging from 100 to 200 Ib BOD/
    day-1,000 cu ft (1.6 to 3.2 kg BOD/day-cu m).  Removals observed
    in this range shown in Figure 26 were only approximately 30
    to 70 percent.
    
    Effect of pH
    
    During the months of November, December, and January, problems
    were encountered in adequately neutralizing the feed to the
    trickling filter system.  In order to demonstrate the adverse
    effect of these pH fluctuations, COD removal is shown as a
    function of the pH range during a particular 24-hr period in
    Figure 27.  Reductions in COD removal efficiency were most
    noted for pH fluctuations of 3 or more pH units.   The pH range
    identified in this figure refers to the difference in the
    minimum and maximum pH values observed during a 24-hr period
    which was sustained for at least 30 min.
    BOD Removal Relationships
    
    A first-order relationship was used to describe BOD removal in
    the trickling filter system:
    
    
        c            -KD/Q
               (1 + N) - N
    
        S   =  influent organic concentration, mg/1
    
        S   =  effluent organic concentration, mg/1
    
        D   =  filter depth,  ft or m
    
        Q^  =  hydraulic loading,  gpm/sq ft or cu m/min-sq m
    
        K   =  substrate removal  rate constant, (gpm/sq ft)n/ft or
               (cu m/min-sq m)  /m
    
        n   =  flow exponent
    
        N   =  recirculation  ratio,  recycled flow/raw waste flow
                                    64
    

    -------
                400
              D
              TJ
              3 300
             o
    
             .o
    
             ~ 200
             UJ
             cc
    
             o
             o
             o
    100
                  0
                          Data from
    
                           11/18/72 to 1/16/73
                        I	I
                                            J	i
                   02^68
    
             pH FLUCTUATION DURING 24-HR PERIOD(max.pH-min.pH)(pH Units)
    FIG. 27. EFFECT OF pH  FLUCTUATION ON TRICKLING FILTER
    
            PERFORMANCE
       (kg/cu m-day= Ib/IOOO cu ft-day x 0.016)
    

    -------
    Preliminary data collected during this investigation indicated
    that the exponent, n, had a value of 1.0.   Variation of the sub-
    strate removal  rate constant, K, was described using the Streeter-
    Phelps relationship:
    
    
              KT   =  KT  0T1"T2
               'l        2
    
    Variation of the value of K with waste and air temperature is
    illustrated in Figure 28.  Data used in this figure were compiled
    for one-week periods throughout the investigation.
    
    From these data, the temperature coefficient, 6, was determined
    to be 1.11 based on air temperature and 1.27 based on waste tem-
    perature.  This is considerably higher than the values which have
    been reported in treating other wastes.  However, there is some
    fundamental basis for the observation of higher 6 values for com-
    plex organic wastewaters such as this one.
    
    The variation of the data shown in Figure 28 was most likely due
    to changes in waste composition that might have occurred during
    the nine-month period of observation.  The line of best fit in
    this figure was drawn including all points obtained from November,
    1972 through May 26, 1973.  Data obtained during the months of
    June and July are also shown in Figure 28, but there was a signi-
    ficant change in waste treatability during this period which can-
    not be attributed solely to temperature differences.  Points for
    June and July are those having air temperatures greater than 19°C
    and waste temperatures greater than 20°C.
    
    While temperature effects on biological processes are usually
    correlated to waste temperature, it can be argued that the tem-
    perature effect in trickling filters is primarily a function of
    air temperature.  This is especially true of filter media which
    is not always covered by a laminar film of wastewater.
    In this case, the organisms are constantly exposed to the atmos-
    phere and not submerged in waste.  For the data collected in this
    investigation, the correlation using waste temperature gave a
    value of 6 which is extraordinarily high,  while the correlation
    with air temperature resulted in a value of 6 very close to that
    obtained in activated sludge investigations discussed subsequently
    in this report.   At this time, no definitive conclusion may be
    reached because of the possible influence of other variables.
                                     66
    

    -------
    \J\JC.
    
    | o.o,
    I 0.008
    i
    j< Q006
    0
    (i! 0.004
     —
    H-
    1
    -S 001
    5 0.008
    1-
    (/)
    g 0.006
    o
    5 0.004
    or
    _i
    5
    o
    ^ 0.002
    0.001
    /
    /
    /
    /
    /
    **
    / •
    i* • / *
    . /f 1 y '0 046=11!
    x •
    
    /
    / • •
    ••^ •
    
    / * *
    4 • *
    •
    1 	 1 	 1 	 1 	 1 	 1 	 — —- 	 	
                   -10  -5   0    5    10    15   20   25    30
                          B. CORRELATION WITH AIR TEMPERATURE
    
    
    
    FIG.28.TEMPERATURE DEPENDENCE OF THE BOD REMOVAL RATE
    
    
           CONSTANT
    
           (cu m/min-cu m=qpm/cu ftx 0.13)
                                     67
    

    -------
    Fate of Solvents In the Trickling Filter System
    
    Samples were taken each week to determine the change in concen-
    tration of solvents in the treatment system.  Correlation of the
    concentrations of these solvents to BOD and TSC measurements made
    for the waste indicated that the solvents accounted for a larqe
    portion of the organic constituents present in the wastewater.
    Variations in the concentrations of these substances through the
    depth of the trickling filter system are shown in Figure 29.
    Values shown in this figure represent averages for all  measure-
    ments made between mid-December, 1972 and July, 1973.  In all
    cases, methyl ethyl ketone and toluene were not observed after
    the first and second towers, respectively.   Detection of odors
    at the tower outlets indicated that the primary removal mecha-
    nism for these substances was by air stripping.  The decrease
    in the isopropanol concentration through the system was accompa-
    nied by an increase in the acetone concentration.  This suggested
    that the disappearance of IPA was partially a result of chemi-
    cal oxidation to acetone.  However, acetone concentrations in-
    creased by approximately 400 mg/1 through the system, while
    IPA concentrations decreased by approximately 700 mg/1.  The
    increase of acetone through the system is not completely under-
    stood; however, it is believed that this is due either to the
    formation of by-products from biological oxidation, or to the
    auto-oxidation of isopropanol  through the system.
    
    The stability of methanol concentrations through the towers is
    of significance because of the highly degradable nature of this
    substance.  In a healthy biological system, it would be expected
    that methanol would be one of the first organic substances to
    be degraded.   However, decreasing concentrations of isopropanol
    through the system indicate that the decrease of this readily
    degradable substance (IPA) might have been  due to biodegradation.
    Because of the heavy organic loading and consequent poor BOD
    removal in the system the stability of methanol might simply be
    a result of the preference of the microorganisms for isopropanol.
    Generally, the data strongly indicate that  some removal of organic
    constituents was accomplished by air stripping (e.g., toluene)
    and that, while there was evidence of biological removal  of
    organic compounds, the extent to which the  compounds were being
    removed was not as great as would be expected in a healthy biologi-
    cal system under normal  loading conditions.
                                    63
    

    -------
      1500
    t 1000
    o
    
    <
    QC
    UJ
    O
    O
    u
       500-
                 0      20     O      60      80      100     120
                                  DEPTH (ft)
    
          FIG. 29 .VARIATION OF SOLVENT CONCENTRATION THROUGH THE
    
                 TRICKLING  FILTER SYSTEM
         (m-ftx 3.3)
    

    -------
    OXYGEN UTILIZATION
    
    Oxygen uptake measurements in the full-scale trickling filter
    system were made to determine the effect of various operating
    variables on the oxygen uptake rate of the biota and as a means
    of elucidating the mechanism of BOD removal in the tower system.
    Oxygen uptake rates for trickling filters are conventionally
    expressed as grams of oxygen used per sq cm of media per hour.
    
    In this application,  the oxygen uptake rate will  be a function
    of the quantity of biota on the media sample,  the organic load
    to which the biota are exposed, and the presence of any toxic
    or inhibitory substances in the wastestream.   The variation of
    oxygen uptake rates as measured through the filter system are
    shown in Figure 30.  The date on which the measurement was made
    and the waste flow to the system are indicated for each measure-
    ment.  For most tests, uptake rates were relatively low through
    the first two filters followed by significantly increasing values
    through the rest of the system.  These results indicate inhibi-
    tion of the biota in  the first two towers followed by decreasing
    inhibition at greater tower depths.  This inhibition might have
    been due either to pH and organic loading shocks felt most sig-
    nificantly in the first two towers or to the presence of inhibi-
    tory or organic compounds which are removed through the system
    either by air stripping or by biological  oxidation.
    
    While these results indicate significantly increased oxygen up-
    take levels at reduced waste application  rates,  it should be
    noted that these tests were made during the months of January,
    February, and March when flows were 1,000, 500,  and 350 gpm
    (3.8, 1.9, 1.3 cu m/min), respectively.   Thus, differences in
    temperature may have  had some influence on these results.
    
    Additional oxygen uptake values determined during the months of
    April and June are also shown in Figure 30.  The uptake relation-
    ship measured on April 26 showed one of the highest levels of
    activity measured during the course of this investigation and
    corresponded to the time period in which  the organic applied to
    the towers was the lowest during the 9-mo study.   Oxygen uptake
    rates measured June 14, when BOD removal  performance of the fil-
    ters was generally poor, showed significantly less activity.
    
    Examination of biota  samples used for oxygen uptake analyses
    showed a significant  increase of slime thickness through the
    treatment system during the spring months.  Slime thickness in
    Towers 1  and 2 were approximately 1 mm or less with thickness
                                    70
    

    -------
       O.I I
    
    
    
       0.10
    
    
    
       0.09
    I  0.08
    D>
    e
    LU
       0.07
       0.06
       0.05
    o  0.04
    
    i
       0.03
       0.02
       0.01
         0
          0
    20
                                900 gpm
    
                                T=25°C
    40     60      80
    
        DEPTH (ft)
    100
     FIG.30. OXYGEN UPTAKE  IN, FULL-SCALE
    
             FILTERS           3
             (cu m/min = gpm x 3.79 x 10 ; m = ft x 3.3)
    120
                             71
    

    -------
    increasing in subsequent towers to approximately 2 mm in the last
    three towers.  During the months of May and June, it appeared
    that a significantly smaller quantity of slime was present in the
    system compared to the spring months.  Periodic microscopic examina-
    tion of slime samples indicated that a significant growth of
    filamentous organisms was present in the system.  Some higher
    forms of life were present, principally stalked and free-swimming
    ciliates.  Round worms, which are usually found in trickling fil-
    ters, were observed only on one occasion.
    
    In order to determine the relative significance of the air strip-
    ping and biological  methods as BOD removal  mechanisms, estimates
    were made from oxygen uptake measurements of the quantity of BOD
    removed biologically.  For days on which oxygen uptake measure-
    ments were made, estimates of the quantity of BOD removed biologic-
    ally were obtained by assuming an oxygen utilization of 1  g/g BOD
    removed.  The quantity of BOD removal  attributable to biological
    mechanisms for each test is shown in Table 5.   On most occasions,
    
                                  TABLE 5
    
                 BOD REMOVAL ATTRIBUTABLE TO OXYGEN UPTAKE
    
    Date
    (1973)
    1/16
    2/28
    3/28
    4/18
    4/26
    6/1
    6/14
    6/22
    
    BOD
    applied
    (lb/day)a
    35,340
    24,020
    18,310
    23,320
    12,610
    21 ,350
    30,080
    52,780
    
    BOD removed
    (lb/day)c
    7,070
    1,800
    6,000
    7,140
    8,080
    6,960
    3,370
    18,580
    (%)
    20
    7.5
    32.8
    30.6
    64.1
    32.6
    11.2
    35.2
    BOD Removal Due to Qo Uptake
    
    (lb/day)a
    1,490
    1,780
    3,970
    5,750
    3,920
    6,980
    3,250
    8,700
    Fraction
    of BOD
    applied
    (%)
    4.2
    7.4
    21.7
    24.6
    31.1
    32.7
    10.8
    16.5
    Fraction
    of all BOD
    removed
    (%)
    21
    99
    66
    80
    48
    100
    96
    47
     '(kg/day = Ib/day x 0.45)
                                      72
    

    -------
    the oxygen uptake rate for the waste alone was determined at two
    or three depths in the tower system.  For measurements made through
    the month of May, the uptake of the control waste sample was very"
    small and did not significantly affect the value measured for the
    uptake of the organisms attached to the filter medium.  For measure-
    ments made during June and July, it was necessary to determine the
    oxygen uptake rate of the waste separately and correct the value
    obtained for the waste plus the medium sample for the uptake of
    the waste alone.  Visual observations indicated that a biologi-
    cal growth established itself in the sumps beneath each tower
    during the summer months.  Because these organisms also contri-
    buted to the biological removal of organic constituents, an
    estimate of the removals accomplished by these dispersed organisms
    were included in estimates of biological BOD removal.
    
    These results show that significantly greater BOD removals were
    attributable to biological mechanisms during the month of April.
    Smaller biological removals of BOD during the months of January
    and February were probably due to lower temperatures and inade-
    quate waste neutralization.  The relatively poor performance
    during the months of June and July cannot be explained.  While
    the quantity of BOD removed biologically varied considerably
    during the 6-mo period of observation, it appeared that biological
    mechanisms account for approximately 50 percent of the total BOD
    removed in the trickling filter system.
    EFFECT OF FORCED DRAFT VENTILATION ON BOD REMOVAL
    
    As a further indication of the relative significance of air strip-
    ping and biological mechanisms of BOD removal, tests were made to
    determine the effect of forced draft ventilation on removal effi-
    ciencies.  For a one-week period during the month of May, dissolved
    oxygen and total carbon values were measured for the effluent from
    each tower with and without the forced air ventilation system run-
    ning.  After the fans had run throughout the night, samples were
    taken with all fans running each morning.  Following the collection
    of samples, the blowers were turned off for several hours to allow
    the system to equilibrate to the new conditions; subsequently,
    samples were taken with the blower system not running.
    
    The results of these tests are summarized in Table 6.  The results
    show that while dissolved oxygen levels were lower in each tower
    when the fans were off, this level was not too low for aerobic
    biological activity.  Total carbon removals for this system for
    the two conditions exhibited significant differences.  For the
                                    73
    

    -------
                                                TABLE 6
    
                              EFFECT OF TOWER BLOWERS ON DISSOLVED OXYGEN
                                    LEVEL AND TOTAL CARBON REMOVAL3
    1 Sample
    Influent
    Tower 1
    Tower 2
    Tower 3
    Tower 4
    Tower 5
    Tower 6
    Dissolved Oxygen (mq/1)
    Fans on
    3.1
    6.7
    7.0
    7.0
    6.9
    7.0
    7.3
    Fans off
    3.2
    5.9
    5.7
    5.2
    4.8
    4.6
    5.0
    	 	 1
    Temperature (°C)
    Fans on
    19.8
    19.8
    19.7
    19.5
    19.2
    19.2
    19.2
    Fans off
    21.0
    21.2
    21.3
    21.6
    21.7
    Total soluble carbon
    Fans onb
    908
    846
    788
    741
    687
    22.3 649
    22.3 611
    j
    i
    Fans offc
    985
    949
    913
    882
    861
    832
    810
     Data  taken daily over period from May 14 to May 19, 1973.
    
    }Removal  averaqed 32.7 percent.
    'Removal  averaged 17.8 percent.
    

    -------
    one-week period, total carbon  removals during periods with forced
    draft ventilation averaged 32.7  percent, while the removal without
    forced ventilation was only  17.8  percent.  Because the dissolved
    oxygen measurements  indicated  that  D.O. was not  limiting the bio-
    logical performance  of the system,  it was concluded that the dif-
    ferences in removal  observed with and without the blowers running
    can be attributed to air  stripping  of volatile components from
    the wastestream.  While some air  stripping probably occurred when
    the blowers were not running,  it  is felt that these reductions
    were minimal due to  the great  reduction of air flow through the
    system.  While  strictly quantitative judgments cannot be made on
    the basis of these data,  it  appears that biological and air strip-
    ping mechanisms were responsible  for approximately the same degree
    of BOD removal, i.e., 50  percent  of the total removal.
     FULL-SCALE  EFFLUENT  RECYCLE  INVESTIGATIONS
    
     Results  of  pilot-scale  trickling  filter  investigations conducted
     earlier  in  the  investigation showed  that effluent  recycle was
     capable  of  improving treatment performance.   Based on these favor-
     able  results, the  trickling  filter system was modified to provide
     continuous  effluent  recycle.   In  making  this  modification to the
     system,  the six trickling  filters were divided into two  parallel
     systems,  each containing three filters  in series.   Flow  recorders
     and controllers were added so that both  the  raw feed rate and the
     recycle  flow could be adjusted.   Recycle flow consisted  of unclari-
     fied  effluent from each of the parallel  systems.
    
     Bank  A (originally Towers 1, 2, and 3)  was  fed 700 gpm  (2.6 cu  m/min)
     of raw waste and 300 gpm (1.1 cu m/min)  of  recycle waste, while Bank B
     (originally Towers 4, 5, and 6) were fed 300 gpm (1.1 cu m/min) of  raw
     waste and 700  gpm (2.6  cu m/min) recycle flow.  Following stabilization
     of this  period  on April 1, 1974, data were  collected to  demonstrate
     the performance of this modified system.
    
     A summary of data obtained for a 7-wk period  is shown in Table 7.
     Weekly data are presented in  Table B2 of Appendix B.  During  the
     recycle  investigations, Bank  A, operated at a recycle ratio of
     0.43, achieved a BOD reduction of 22 percent which was  somewhat
     less  than the 1973 average of 32 percent for six filters in series.
     Bank B, operated at a  recycle ratio of  2.33, achieved approximately
     45 percent BOD reduction.  For operation at  identical  hydraulic
     loading rates,  it would be expected that the three filters  in
     Bank A would achieve less BOD removal than six filters  in series.
     The lower organic concentration in the  first filter would probably
     reduce air stripping of organics but might not be significant
                                       75
    

    -------
                                                        TABLE 7
                                                 RECYCLE DATA SUMMARY8
    Bank
    A
    B
    Recycle
    0.43
    2.33
    Air
    temp .
    (°c)
    11.4
    11.4
    BOD results
    Inf. Eff.
    (mg/1)
    2,203
    2,203
    1,711
    1,216
    Reduction
    (*)
    22.3
    44.8
    Applied load
    (lb/1000 cu ft-day)D
    820
    605
    COD results
    Inf. Eff.
    (mg/1 )
    3,925
    3,925
    3,330
    2,683
    Reduction
    U)
    15.1
    31.6
    Applied load
    (lb/1000 cu ft-day)
    1,500
    1,220
     Data summarized for operation during 7-wk period from April  1 to  May  19,  1974.
    ^Loading in kg/cu in-day = lb/1 ,000 cu ft-day x 0.016.
    

    -------
    enough to enhance BOD removal.  On the other hand, reductions in
    Bank B, operated at a recycle ratio of 2,33, were significantly
    greater than the 1973 average.  This was perhaps due to the dilu-
    tion of the influent organic concentrations and dampening of flue-
    tuations in the organic load to the filter.
    
    On a BOD basis, the total load applied to Bank A (including the
    BOD content of the recycle stream) was approximately 820 Ib BOD/
    1,000 cu ft-day (13 kg/cu m-day), while that applied to Bank B
    was approximately 600 Ib BOD/1,000 cu ft-day (9.6 kg/cu m-day).
    This is somewhat higher than the total load applied to a system
    without recycle.  However, the load applied to the first tower
    in Bank B  (approximately 1,800 Ib BOD/1,000 cu ft-day or 28.8
    kg/cu m-day) was significantly less than the load of approximately
    3,000 Ib BOD/1,000 cu ft-day  (48 kg/cu m-day) applied to the
    first tower when six filters were operated  in series.
    
    It should  be mentioned that the  biota present in Bank B at the
    beginning  of these tests was  probably better developed than that
    present  in Bank A.  Operation of the recycle system over a longer
    period of  time might result in greater BOD  reductions at a re-
    cycle  ratio of approximately  0.4 than those experienced in this
    investigation.
                                    77
    

    -------
                               SECTION  VIII
    
                           AUTOMATIC MONITORING
    One objective of this grant was to evaluate the potential for
    controlling the multi-stage trickling filter system using auto-
    matic monitoring equipment.  The methods to be evaluated in-
    cluded control of the raw waste feed rate using automatic total
    carbon measurements and control of the blower speed in the forced
    air ventilation system using dissolved oxygen measurements.
    Tests conducted during this investigation had the objective of
    demonstrating the applicability of automatic monitoring equip-
    ment in the trickling filter system.  The investigation did not
    include control of the feed rate or blower speeds; however,  a
    control system could be designed once the stability of monitoring
    systems has been established.   During the fall  and winter of 1973-
    1974, dissolved oxygen and total carbon monitoring equipment was
    installed to measure the contents of each sump and the clarifier
    effluent.  A more complete description of these systems is pre-
    sented in Section IV.
    DISSOLVED OXYGEN MONITORING
    
    Comparative dissolved oxygen analyses were made of measurements
    from the on-line system and a laboratory dissolved oxygen meter.
    For each comparison, grab samples  were taken from the line feeding
    each D. 0.  probe.   Simultaneous readings were made from the on-line
    D. 0. indicator.  The portable laboratory dissolved oxygen meter
    was taken to the field to provide  a comparison for values measured
    using the on-stream system.  This  portable meter was calibrated in
    the laboratory prior to each use.   A least squares analysis was
    performed on comparative analysis  at each sampling point over a
    one-month period.   Results of these analyses and average U. 0.  con-
    centrations observed for both the  laboratory and on-stream systems
    are summarized in  Table 8.  During this period routine maintenance
    in the system consisted of cleaning the probe assemblies at least
    once each week and recalibration of each probe approximately two
    times per week in  order to maintain good agreement between the on-
    stream and  laboratory analyzers.
    
    The data presented in Table 8 show that the average D.  0. differ-
    ences between the  two measurements ranged from 0.0 to 0.4 mg/1 for
                                    78
    

    -------
                                  TABLE 8
    
                 COMPARATIVE DISSOLVED OXYGEN MEASUREMENTS
    Sample
    location
    Tower 1
    Tower 2
    Tower 3
    Tower 4
    Tower 5
    Tower 6
    Clarifier
    Average D. 0.
    concentration3 (mq/1)
    lab
    meter
    9.0
    8.5
    8.9
    8.4
    8.4
    8.9
    7.0
    on-stream
    system
    8.9
    8.2
    8.9
    8.3
    8.2
    8.5
    6.0
                  Averages are from 14 comparative measure-
                  ments made during a one-month period.
    
    each of the towers and 1.0 mg/1 for the clarifier probe.   Consider-
    able difficulty was encountered in obtaining proper operations of
    the clarifier probe.  Shortly before investigations with the auto-
    matic monitoring system were initiated, chlorination of the efflu-
    ent was begun by adding approximately 50 mg/1 chlorine to the
    clarifier influent.  As long as the clarifier probe remained
    immersed in the waste, readings recorded in the automatic moni-
    toring system for this probe continually drifted downward.  Upon
    changing the membrane of this probe and placing it in contact with
    tap water, readings made over a one-week period indicated that
    stable operation could be maintained with tap water.  When the
    probe was returned to the wastewater system, the same lack of
    stability was noted and readings again drifted downward.
    
    The least squares analysis of data for each sampling point indi-
    cated that somewhat lower readings were obtained in the on-stream
    system compared to  laboratory measurements.  A regression analysis
                                     79
    

    -------
    of all data collected had a slope of 1.00 and y-intercept of -0.4
    mg/1.   This indicated that measurements using the laboratory meter
    were approximately 0.4 mg/1 greater than measurements in the con-
    tinuous-flow system.
    
    Additional measurements were taken to determine the operation of
    the system when calibrated less frequently.  While collecting data
    summarized in Table 8, each probe was recalibrated approximately
    two times per week.  During a subsequent period, probes were cali-
    brated approximately once each two weeks.   Data collected with
    less frequent calibration showed that readings with the monitoring
    systems tended to drift downward.  Comparative analyses made
    during this period showed that on-stream measurements averaged
    approximately 1.1 mg/1 lower than equivalent measurements made
    using the laboratory analyzer for each of the tower probes.  Dis-
    solved oxygen concentrations indicated with the clarifier probe
    averaged approximately 3 mg/1 less than comparative analysis made
    with the  laboratory meter.
    
    Observations made during this period showed the need for calibra-
    tion of the system approximately twice each week.   Experience
    indicated that if the probes were not cleaned or calibrated for a
    period of one week, the dissolved oxygen concentrations were
    approximately 20 percent lower than measurements made using the
    laboratory meter.  Operationally, the system was well designed to
    allow for routine maintenance.   The only maintenance required
    included cleaning and recalibration of each probe assembly peri-
    odically.  To disassemble and clean the probe assembly, change
    the membrane, air calibrate the instrument, and reassemble the
    probe unit required approximately two hours per probe.   Thus, ap-
    proximately two days were required to clean and recalibrate the
    seven probes included in this system.
    
    
    TOTAL CARBON MONITORING SYSTEM
    
    During the initial one-month period of operation,  distinct sample
    peaks were obtained only five days.   Of the other days  during this
    period, the instrument was not operational  due to plugging of the
    sample prefiltration system (1  day), a leaking sample injection
    valve (16 days), and a plugged injection tube (2 days).   During
    this test period the analyzer was not operational  due to mechanical
    malfunctions 75 percent of the time.  During the remaining 25 per-
    cent of the test period, values were recorded; however,  most of
    these values did not agree well  with laboratory measurements.
                                     30
    

    -------
    Required maintenance included replacement of the sample injection
    valve, packing of the reaction chamber with a new catalyst, re-
    placement of the oven and mounting plate, cleaning of the flow
    regulator, and complete calibration of the instrument.  The ori-
    ginal catalyst used in the reaction chamber became poisoned soon
    after the instrument was placed into operation.  Although a
    second type of catalyst was evaluated, the same problem recurred.
    It appeared that problems with plugging of the sample injection
    tube, poisoning of the catalyst, and leakage in a block unit used
    to meter samples into the reaction chamber were all caused by
    tar-like and other substances in this particular wastewater.
    
    During the five days in which distinct sample peaks were obtained
    from the instrument, total carbon concentrations ranged from 50
    to 65 percent of values measured using the laboratory organic
    carbon analyzer.  Because of the more consistent operation of the
    laboratory instrument, it was apparent that values determined
    using the on-stream analyzer were incorrect.  Laboratory opera-
    tion of the total carbon analyzer prior to its installation in
    the continuous-flow system indicated that several injections
    (approximately 3 to 6) were necessary to obtain consistent read-
    ings from each sample.  Additionally, it was found that the injec-
    tion of 5 to 8 distilled water samples were necessary to purge
    the reaction chamber when changing from one sample to another.
    Since the multi-stream selector was designed to make only one
    injection of each waste sample alternated with one injection of
    distilled water, consistent operation of the instrument was not
    obtained.
    
    During a two-month test period, operation of the total carbon
    analyzer was unsatisfactory.  Even with a high degree of mainte-
    nance, the instrument was incapable of properly measuring and
    recording the total carbon of waste samples from various points
    in the treatment system.  It  is believed that problems encountered
    in using this instrument were due to the type of materials which
    are not uncommon in wastewaters produced in most diversified
    organic chemical plants.
                                     81
    

    -------
                                SECTION IX
    
                      ACTIVATED SLUDGE INVESTIGATIONS
    Activated sludge investigations were conducted in three phases.
    Phase I was initially conducted to determine the feasibility of
    activated sludge treatment for this waste.   Phase II investiga-
    tions were continued from the Phase I investigation to determine
    longer range performance of these units and to determine the
    effects of temperature on removal efficiencies.   Phase III tests
    were conducted in order to compare differences in the response
    of the waste to treatment using air and oxygen aeration.  The
    results of these investigations are described in this chapter.
    AIR AERATION TESTS
    
    During Phase I investigations, activated sludge units were fed
    raw equalized waste, unclarified trickling filter effluent, and
    clarified trickling filter effluent.   The objectives of this por-
    tion of the investigation were to determine the removals of organ-
    ic constituents possible using activated sludge treatment, to
    determine kinetic parameters required for process design, and to
    determine the effect of pretreatment in the present trickling
    filter system on the effectiveness of activated sludge treatment.
    Five 40-gal (151 liter) activated sludge units were operated
    during this portion of the study.
    
    After a five-week stabilization period, the units were judged to
    be acclimated to the waste and the comprehensive testing program
    was begun.  Data for these tests were collected over a seven-
    week period from January 11 to March 3, 1973.
    
    Phase II investigations were initiated on March 10 and continued
    until May 26, 1973.  One unit was placed outside and allowed to
    operate at the ambient temperature.   Two other units were operated
    indoors at a temperature of approximately 18°C.
    Substrate Removal
    A summary of operating results for Phase I is shown in Table Cl of
    Appendix C.  For units receiving the unclarified trickling filter
    effluent feed,  the influent total  BOD concentration averaged 2,270
                                    82
    

    -------
    mg/1.  Total effluent BOD concentrations averaged 15, 53, and
                                                         ,   ,
    0 pd        p       f°r UnitS Operated at F/M ratios of 0.08,
    0 23  and 0.40.  Percentage removal efficiency ranged from 92
     w  Tonf* /huS' While the waste can be treated to low
    effluent BOD values, these values can be achieved only at low
    F/M ratios.                                          J
    
    Table C2 contains data for all units operated at temperatures
    ranging from 14 to 18 C  during Phase II.  Table C3 contains data
    for a three-week period  in which the temperature of the outside
    units averaged 6 C.  Effluent BOD values were 26 and 71  mg/1
    respectively, for units  operated at 17 and 6°C, while the in-
    fluent BOD was 1 ,100 mg/1 .
    
    The variation of soluble effluent BOD with the substrate removal
    rate for Phase I and Phase II is shown in Figure 31.  These data
    show that the BOD removal rate constant, k, was 0.0045 1/mg-day.
    The average basin temperature during this study was 18°C.
    
    From basic principles describing the activated sludge process, a
    linear relationship is expected between soluble effluent BOD and
    the substrate removal rate.  Greater slopes from this relation-
    ship indicate greater amenability to activated sludge treatment.
    Deviation from this linear relationship is usually found at high
    substrate removal  rates.
    
    Because of the significant weekly variability of this waste,  a
    statistical distribution of substrate removal rate constants  was
    developed from data collected during this part of the investiga-
    tion.  On a BOD basis, the substrate removal rate constant, k,
    varied from approximately 0.0013 to 0.017 1/mg-day, with higher
    substrate removal  rate constants concurrent with periods of
    clearer effluent.   Because of the variability of manufacturing
    operations in the plant, the long-term observation of treatability
    characteristics of this  waste is important for the proper design
    of an activated sludge system.  For operation at constant F/M
    values, the effluent BOD will vary in proportion to the value of
    the substrate removal rate constant.
    
    The principal effect of  temperature changes on the activated
    sludge process is manifested in the effect on the substrate re-
    moval rate constant, k.  A decrease in temperature will  decrease
    the rate of biological metabolism which reduces the observed  k
    value.  For a system treating a given volume of waste, operation
    at reduced values of k will result  in an increased BOD concen-
    tration.  To determine the effects of low temperatures on the
                                     no
                                     OJ
    

    -------
    Q
    
    §
    cc.
    0.7
    
    
    
    0.6
    
    i
    
    0.5
    »
    
    
    0.4
    
    
    
    0.3
    LU
    a:
    LU
    DQ
       O.i
       O.O
                                        1	1	1	r
                                                            -i	r
                  PHASE I
    
               A Raw Waste
               • Unclarified Effluent
               • Clarified Effluent
                   PHASE
             oAD Unclarified Effluent
                                       k = 0.0045 liter/mg-day
                                       T= I8°C
      0
                20     40    60     80     100    120    140
                            SOLUBLE EFFLUENT BOD, Se (mg/l)
                                                                160     180
           FIG. 3 I  .  BOD REMOVAL  RATE CONSTANT - PHASES I
                      AND I
    

    -------
    biological process, all three units in Phase II were operated in
    parallel receiving the unclarified trickling filter effluent as
    feed.  The relationship of soluble effluent BOD to the substrate
    removal rate at different temperatures is shown in Figure 32.
    The relationship used to relate the change of the substrate
    removal rate constant with temperature is expressed as:
                                  =  kn
                                         JrT2
    The symbol, 8, is the temperature coefficient for the system.
    From the BOD removal rate constants determined in Figure 32, the
    value of 9 was determined to be  1.09.  Due to the short sampling
    period the collection of additional data would be advisable to
    confirm this value.
    Oxygen Requirements
    
    Oxygen requirements may  be calculated from a correlation of the
    substrate removal rate with  the oxygen utilization rate expressed
    as grams oxygen utilized  per gram MLVSS per day.  The slope of
    the  line defined by this  relationship represents the assimilative
    oxygen utilization coefficient, a1, while the intercept on the y-
    axis represents the endogenous oxygen utilization coefficient, b'.
    
    The  data illustrated  in  Figure 33 show that oxygen requirements
    for  this waste are 1.12  g Og/g BOD  removed and 0.03 g 02/g MLVSS-
    day.  The oxygen utilization coefficient is somewhat higher than
    usually encountered for  aerobic biological treatment systems,
    while the endogenous  utilization coefficient  is somewhat lower
    than usually measured.
    Sludge  Production
    
    The production of  biological  sludge  is  directly  proportional to
    the quantity of organic matter  removed.   The  net sludge growth is
    the sum of the sludge  growth  resulting  from the  removal of organic
    constituents and the decrease in  sludge mass  due to endogenous
    respiration of the microorganisms.
    
    Since sludge production is directly  related to the organic loading
    rate, the net sludge production rate is correlated to the substrate
                                      35
    

    -------
    00
    ON
                     Q
                     O
                     CD
    $0.3
                       o>
                       UJ 0.2
                       <
                       a:
                       UJ O.I
                       cr
                       LU
                       cc
    
                       CO
                       CD
    
                       CO
       0
                         /
                      * /3k = 0.00!
                      • ' T=I7°C
                                              0.0050 l/mg-day
                                                C
                      Jk=0.002 l/mg-day
                      T=6°C
        0     20     40    60    80     100
    
           SOLUBLE EFFLUENT BOD, Se (mg/l)
             FIG.32. TEMPERATURE EFFECT  ON  ACTIVATED SLUDGE
                    PERFORMANCE
    

    -------
                         0.8
    CD
    -J
                         0.7
                      t
                      §  0.6
    
                      I
                      9!  0.5
                      LJ  0.4
                      oc
    0.3
                      I
                      5  0.2
                      X
                      o
                         O.I
                        0.0
               PHASE I
           A RAW WASTE
           O UNCLARIFIED EFFLUENT
           ti CLARIFIED  EFFLUENT
                                  PHASE IE
                                 A UNIT C
                                 • UNIT D
                                 • UNIT F
                                 '» Q03 90,/g MLVSS- doy
    0.0      O.I      0.2      0.3      0.4
                SUBSTRATE  REMOVAL RATE,
                                               0.5
                                                                           0.6
    0.7
                         FIG.33.DETERMINATION OF OXYGEN UTILIZATION COEFFICIENTS,
                                 BOD  BASIS- PHASES I  AND H
    

    -------
    removal rate.   The slope of the line represented from this rela-
    tionship is the sludge yield coefficient, a, and the y-intercept
    is the endogenous decay rate, b.   The data correlated in Figure 34
    define a sludge yield coefficient of 0.37 g VSS/g BOD removed
    and an endogenous decay rate of 0.02 g VSS destroyed/g MLVSS-day.
    
    In order to determine the total  sludge solids produced, the vola-
    tile content of the wasted sludge must also be known..  Measurements
    made over the duration of this study showed that the volatile fraction
    of mixed liquor solids ranged from 74 to 83 percent for the five units
    operated.
    Sludge Settleability
    
    Sludge settling, as measured by the sludge volume index and the
    zone velocity tests, was determined during the course of the in-
    vestigation.  Because sludge settling in small-scale units does
    not adequately simulate the performance which can be achieved in
    prototype clarifiers, additional  tests were made to determine the
    probable concentration of effluent solids from full-scale activated
    sludge treatment.   For most organic loadings the sludge volume
    index was less than 60 ml/g.  While the data indicate that the best
    sludge settleability is obtained  at higher organic loadings, efflu-
    ent suspended solids data show that a higher concentration of
    solids is present in the effluent at high loadings.  Average values
    for the zone settling velocity ranged from 13.6 to 24.1 ft/hr
    (4.15 - 7.34 m/hr).  The highest  zone settling velocity was ob-
    tained at an F/M of 0.23/day using the unclarified trickling filter
    feed.  Compared to values usually obtained for these measures of
    sludge settleability, this sludge settled very well.
    AIR AND OXYGEN AERATION COMPARATIVE TESTS
    
    For the Phase III investigations two of the 55-gal  (208 liter)
    activated sludge units were modified to be operated using oxygen
    aeration.  In order to determine the effect of pretreatment by air
    stripping on the treatability of the waste, one air and one oxygen
    unit received a stripped waste feed.  Two other units received a
    feed consisting of raw equalized waste.  A summary  of the operating
    data for this portion of the investigation is shown in Table B4 of'
    Appendix B.   The quantity of oxygen fed to the oxygen activated
                                     88
    

    -------
    00
    VQ
    Q.
    CO
    
    o»
             0.3
           CO
           CO
             0.2
           o»
              O.I
    o:
    CD
    iu  0.0
    CD
    Q
    
    CO
                  PHASE I
              A RAW WASTE
              O UNCLARIFIED EFFLUENT
              Q CLARIFIED EFFLUENT
                PHASE H
                 UNIT C
                 UNIT D
               • UNIT F
                0.0
                          J_ b=0.02/day
                  O.I
    0.2
                                     0.3
                           SUBSTRATE REMOVAL RATE
     0.4       0.5
    Sr    gBODr
    Xvt CgMLVSS-day
    0.6
    0.7
              FIG.34. EXCESS  SLUDGE PRODUCTION, BOD  BASIS-
                      PHASES IANDH
    

    -------
    sludge systems receiving unstripped and stripped waste required approxi-
    mately 7 cu ft/day (0.2 cu m/day) to maintain a dissolved
    oxygen in the mixed liquor of 5 mg/1 or higher and to maintain the
    oxygen content in the off-gas less than or equal to 50 percent.
    The average volumes of off-gas measured were greater than would
    be expected, indicating the presence of some leaks in the system.
    However, the volume of gas flowing through these systems was con-
    siderably less than the approximately 1,800 cu ft/day (51 cu m/day)
    which passed through the air activated sludge systems.
    
    Mhile oxygen aeration is usually technically feasible in cases
    where air activated sludge treatment may successfully be employed,
    several considerations warranted a feasibility study regarding the
    use of oxygen in this case.  Because problems were encountered in
    Phase I tests due to the tendency of the aeration basin pH to
    decline below 6.0, there was concern that pH stabilization would
    prove even more difficult in oxygen systems containing a high
    partial pressure of C02 in the gas phase above the mixed liquor;-
    
    An additional indication of the need for a feasibility study was
    the apparent contribution of air stripping as a significant BOD
    removal mechanism in the air aerated systems.  Because there was
    reason to believe that inhibitory constituents in the waste were
    being removed by air stripping, there was the possibility that
    these substances might accumulate in an oxygen aerated system and
    be detrimental to treatment performance.
    Substrate Removal Relationship
    
    The BOD removal rate constants for the unstripped waste are defined
    in Figure 35.  The value of k for the air system was 0.0034 1/mg-day
    which was somewhat less than that found in previous investigations.
    This is more significant when it is realized that the average basin
    temperature for these tests was 23°C compared to a value of 18°C for
    previous investigations.  The difference in these values is perhaps
    a result of the withdrawal of some cooling flow from the plant
    wastestream which might have resulted in the increase in concentra-
    tions of some inhibitory substances.  The BOD removal rate constant
    for the oxygen system was 0.00083 1/mg-day, a value significantly
    lower than that measured for the air system.
    
    Similar BOD removal  relationships for units receiving the stripped
    waste feed are shown in Figure 3:6.  BOD removal rate constants meas-
    ured for these units were 0.0041 1/mg-day for the air unit and 0.0076
                                    90
    

    -------
                 100
                                                    700
                           200     300     400     500     600
                           SOLUBLE EFFLUENT BOO, Se (mg/l)
    FK3.35.BOD REMOVAL  RATE CONSTANT,  UNSTRIPPED  WASTE-PHASE  III
                    0.6|—i	1	1	1	1	r	i	1	1	1	r- "
              ?  n.
    to
    I
    o
                 0.5
                 0.4
             a   0.3
             _i
    
             o
    
             I   0.2
             UJ
             8   oj
                        Oxygen - Unit D
                                         k=OD04l
                                         l/mg-doy
                                         T=23"C
    
                                     Air-Unit C
                   0     20    40     60     80     100    120
                         SOLUBLE EFFLUENT BOD, Se (mg/l)
    
    FIG. 36.BOD REMOVAL RATE CONSTANT, STRIPPED WASTE-PHASE TH
                                   91
    

    -------
    1/mg-day for the oxygen unit.   Although these data exhibited signi-
    ficant scatter, it appeared that the BOD removal  relationship for
    the oxygen unit was somewhat better than for the air system.  These
    data indicate that,  in  fact, some  volatile  constituent  present in
    the raw wastestream was purged from the waste by the air strip-
    ping pretreatment and through  aeration in the air activated sludge
    system.  Further, it is evident that this substance was not removed,
    or not nearly to such a great  degree, in the oxygen system receiving
    the unstripped waste feed and  that this substance resulted in a
    significant deterioration of performance in the closed-atmosphere
    oxygen system.
    
    Following the conclusion of-this investigation on July 28, Units
    III-A and III-B were kept in operation.  The operation of Unit III-B
    was changed from oxygen to air aeration in  order to determine
    whether or not the BOD removal performance  of this unit would ap-
    proach that of Unit III-A under similar operating conditions.  The
    chronological variations of control  parameters for these units are
    shown in Figure 37.  These data show that these units were operated
    under essentially identical conditions for  a four-week period and
    that the effluent BOD and COD  concentrations of Unit III-B decreased
    and became identical to effluent values from Unit III-A during this
    period.  These data give further substantiation to the hypothesis
    that some volatile constituents accumulated in the mixed liquor of
    the oxygen-aerated units receiving the raw  waste  feed.
    
    It is also significant to note that performance in the air system
    was somewhat improved following the air stripping pretreatment.
    This is evidenced by the k values  of 0.0034 and 0.0041  1/mg-day for
    units receiving the unstripped and stripped waste feed, respectively.
    No adequate explanation for the superior performance of the oxygen
    units compared to the air system receiving  the stripped waste feed
    can be offered which is consistent with other data observed for air
    and oxygen activated sludge treatment.
    Oxygen Utilization
    
    Oxygen utilization data for units receiving the unstripped waste
    feed are shown in Figure 38.   From these data,  values of the assimi-
    lative oxygen utilization coefficient,  a',  were determined to be
    1.14 and 0.81 g Oz/g BOD removed for oxygen and air aeration,
    respectively.  Values for units receiving the stripped waste feed
    (Figure 39) were 0.89 and 0.68 g 02/g BOD removed for oxygen and air
    aeration, respectively.   In both cases  the  values for oxygen units
                                     92
    

    -------
       6000
                          10     15
                             AUGUST
    FIG.37. PERFORMANCE OF OXYGEN-ACCLIMATED SLUDGE
          SUBJECTED TO AIR AERATION
                           93
    

    -------
     D
    
     T3
       0.7
    UJ
    cr
    Z
    UJ
    &
    
    s
       0.6
       0.5
       0.4
       0.3
       0.2
                  O.I
              t     i     i
                           Oxyge
                        I b' = O.07 g
    g 02/gMLVSS-doy
                                      0.6
                                                       0.7
                                  0.8
              0    O.I    0.2   0.3   0.4   0.5
    
                  SUBSTRATE REMOVAL RATE, ^
    
    
    
    FIG.38. OXYGEN UTILIZATION FOR UNSTRIPPED WASTE, BOD BASIS-
    
    
           PHASE m
     o
      0     O.I     0.2    0.3
    
    
      SUBSTRATE REMOVAL RATE,  ^r  f-
                            Xvt  \ i
                                        0.4   0.5   0.6    07
    
    
                                           .' g MLVSS -day j
    
    
    FIG.39. OXYGEN UTILIZATION FOR STRIPPED  WASTE, BOD  BASIS
    
          PHASE m
                          94
    

    -------
    were significantly higher than  for air  aeration  indicating BOD
    removal by air stripping.
    Sludge Settleability and  Effluent  Solids  Concentration
    
    Data summarized  in Table  B4  of  Appendix B show that  sludge settle-
    ability as measured by  the sludge  volume  index and zone settling
    velocity tests was very good for all  units.   However, the units
    operated using oxygen aeration  did exhibit lower  SVI values of 37
    and 48 ml/g  (unstripped and  stripped  waste)  compared to 55 and 61
    ml/g for air aerated units.   Values for the zone  settling velocity
    were not as  conclusive.   While  sludge settling measured for all
    units was very good, effluent suspended solids concentrations were
    high.
    SUMMARY
    
    Activated sludge  investigations  showed  that  the waste  is amenable
    to treatment using  this  process.   However, extremely low organic
    loadings (F/M  ratios) were  required  to  achieve effluent BOD values
    less than 30 mg/1.   Process performance was  significantly impaired
    using oxygen aeration in a  closed  atmosphere system treating the
    unstripped waste.   Performance using oxygen  aeration treating a
    stripped waste was  equal  to or better than that obtained with air
    aeration.  However,  the  failure  of the  unstripped waste oxygen
    unit to produce acceptable  BOD values raised questions regarding
    the feasibility of  a staged-oxygen process treating a  stripped
    waste.
    
    Values for kinetic  parameters determined in  this investigation are
    presented in Table  9.   Data correlated  on a  COD basis  are also
    presented for  comparison with BOD  data.   Some variation of data
    was apparent during the  Phase III  investigation when the plant
    was operating  on  a  heavy production  schedule.  Sludge  production
    data for Phase III  were  scattered; however,  it appeared that the
    production was not  significantly different from that observed in
    Phases I and II.
    
    The BOD removal rate constants corrected to  20°C for different
    phases of the  investigation are  shown in Figure 40.  Data points
    shown in this  figure are averages  for entire portions  of the inves-
    tigation.  These  data indicate the poor performance of oxygen
                                     95
    

    -------
                                                                                       TABLE 9
    
                                                                     SUMMARY OF ACTIVATED SLUDGE DESIGN PARAMETERS
    VO
    Parameter
    Aeration
    Temperature
    BOD Basis
    BOD Removal Rate Constant3, k (1/mg-day)
    Sludge Yield Coefficient, a (g VSS produced/g BODr)
    Endogenous Respiration Rate, b (g VSS destroyed/day-
    g MLVSS)
    Assimilative Oxygen Utilization Coefficient, a1 (g 02/g BODr)
    Endogenous Oxygen Utilization Coefficient, b1
    (g 02/g HLVSS-day)
    COD Basis
    COD Removal Rate Constant, k (1/mg-day)
    Sludge Yield Coefficient, a (g VSS produced/g CODr)
    Endogenous Respiration Rate, b (g VSS destroyed/day-
    g MLVSS}
    Assimilative Oxygen Utilization Coefficient, a'
    (g 02/g CODr)
    Endogenous Oxygen Utilization Coefficient, b'
    (g 02/g MLVSS-day)
    Phases I and II
    Air
    17
    
    0.0048
    0.38
    
    0.02
    1.11
    
    0.03
    
    0.0025
    0.18
    
    0.02
    
    0.67
    
    0.03
    Air
    18
    
    0.0042
    0.37
    
    0.02
    1.14
    
    0.02
    
    0.0024
    0.25
    
    0.02
    
    0.79
    
    0.02
    Phas
    Unstripped Waste
    Air
    - 23
    
    0.0034
    b
    
    c
    0.81
    
    0.07
    
    0.0016
    d
    
    e
    
    0.62
    
    0.055
    Oxygen
    25
    
    0.00083
    b
    
    c
    1.14
    
    0.07
    
    0.00097
    d
    
    e
    
    0.78
    
    0.055
    e }II
    Stripped Waste
    Air
    23
    
    0.0041
    b
    
    c
    0.68
    
    0.06
    
    0.0048
    d
    
    e
    
    0.43
    
    0.055
    Oxygen
    25
    
    0.0076
    b
    
    c
    0.89
    
    0.06
    
    0.010
    d
    
    e
    
    0.57
    
    0.055
                             aValues given for temperatures  at which  Investigations were made.
                             ^Average value of the sludge yield coefficient was  0.30  g  VSS  produced/g  BODr.  However, data were not sufficiently  accurate
                              to permit determination of values for each  unit.
                             cAccurate determination of b could not be  made from data available.   However, value was not  significantly different  from 0.02/day
                              determined In earlier tests-.
                             ^Average value for all units was  0.18 g  VSS  produced/g CODr.
                             eAverage value appeared to be 0.02/day.
    

    -------
           0.5
    VD
                                                   June
                                                   June-July
                                     All values corrected to 20 °C
                                     using 0 = 1.09
    50
    100     150     200    250  '  500
        SOLUBLE  EFFLUENT BOD, Se (mg/l)
                                                               550
    600
            FIG.40.SUMMARY OF  BOD REMOVAL RELATIONSHIPS  FOR
                  ACTIVATED SLUDGE SYSTEMS
    

    -------
    aeration for the unstripped waste and the beneficial  effect which
    air stripping pretreatment had on the performance of both air and
    oxygen aeration.  The great weekly variations of k for Phases I
    and II must be taken into account in the final  process design.
    
    Oxygen transfer characteristics for the activated sludge effluent
    were determined several  times during the investigation.   The mini-
    mun alpha value was 0.45.  Repetition of the tests in warm weather
    generally confirmed earlier data and demonstrated that a value of
    approximately 0.4 should be used for design.
    
    In general,  activated sludge  treatment was characterized by  high
    effluent suspended solids (90 - 175 mg/1),  high refractory effluent
    COD (275 - 500 mg/1), a  high temperature dependence (6 = 1.09),
    low oxygen transfer characteristics (a = 0.45), and a low BOD re-
    moval  rate constant, k.   Sludge settleability was good throughout
    most of the investigation.
                                   98
    

    -------
                                SECTION  X
    
                     ACTIVATED  CARBON  INVESTIGATIONS
    Activated carbon  investigations were  performed to determine the
    feasibility of this process  for achieving additional removal of
    organic substances from  the  biological effluent.  Initially,
    batch isotherm tests were conducted to determine the amenability
    of various carbons for use in  treating this waste and to deter-
    mine the effect of pH on adsorption efficiency.  Subsequent
    tests were performed in  column systems to determine breakthrough
    characteristics for the  most promising carbons identified in the
    batch tests.  While most column tests were conducted using acti-
    vated sludge effluent to determine removals of refractory organic
    substances, some  column  tests  were conducted using the more concen-
    trated trickling  filter  effluent.  Results of both batch and column
    tests are summarized in  this section.
    ISOTHERM TESTS
    
    Batch isotherm tests were conducted at room temperature (approxi-
    mately 20°C) by contacting  the carbon with activated sludge efflu-
    ent for a 24-hr period  in flasks attached to a wrist-action shaker.
    In most cases, several  runs were made for each individual  carbon
    in order to minimize the effect of variations in wastewater compo-
    sition.  It was found that  while the adsorption capacities ob-
    tained for individual runs  might vary significantly with wastewater
    composition, the relative ranking of various carbons by capacity
    remained basically unchanged for most of the runs.
    
    Results from the isotherm tests for COD removal were correlated
    using the Freundlich isotherm.  However, color removal data did
    not follow this isotherm and was correlated using the relationship:
    
    
                                y - A (xk)
    
    where y is the equilibrium  in color concentration in APHA units,
    X is the carbon dose in mg/1, A is the ordinate intercept in APHA
    units, and k is a constant  determined from the slope of the line
                                    99
    

    -------
    obtained plotting equilibrium color concentration versus carbon
    dose.   Using this relationship lower values of A and increasing
    values of the absolute k indicate increasing affinity for color-
    producing substances.
    
    Carbon isotherms were  measured with Hydrodarco 4,000, Filtrasorb
    400, and Westvaco Aqua Nuchar 8 x 30 carbons.   Although nine
    different carbons were tested, these carbons showed the best per-
    formance for COD removal in initial isotherm screening tests,
    color removal, and combined COD and color removal  characteristics.
    A summary of the data  obtained from these isotherms is presented
    in Table 10.  Calgon Filtrasorb 400 and Westvaco 8 x 30 showed the
    highest affinity for COD removal, while the Hydrodarco and Westvaco
    carbons showed the greatest affinity for color removal.
    
                                TABLE 10
    
                         CARBON ISOTHERM RESULTS
    
                     USING ACTIVATED SLUDGE EFFLUENT
    
    
    
    Carbon
    
    Hydrodarco 4000
    Filtrasorb 400
    Westvaco aqua
    nuchar 8 x 30
    COD isotherm
    extrapolated
    capacity, X/M
    (g COD/
    g carbon)
    0.6
    1.3
    
    4.8
    
    1
    n
    
    0.86
    0.50
    
    1.80
    Color isotherm
    k
    APHA units
    (mg/l)
    
    0.650
    0.264
    
    0.585
    
    A
    (APHA units)
    
    67
    220
    
    120
    Additional batch tests were made to determine the effect of pH on
    adsorption performance.  Tests were run as described previously
    except that the pH of the wastewater sample was adjusted prior to
    contacting with the carbon.  Following the 24-hr equilibration
    period, the sample was filtered and the pH adjusted back to 7.0
    prior to analysis for residual COD and color.  The results of
    these tests are presented in Figure 41.  Because it was necessary
                                     100
    

    -------
       200O
        1500
        1000
         500
    
    1
    5      o
    <  2000
    Q.
     1500
    
    
    
     1000
    
    
     500
    
    
       0
    2000
    
    
     1500
    
    
    
     1000
    
    
    
     500
            .   HLTRASORB 400
              HYDRODARCO 4
           A COD (Blank 310 mg/l)
    
           • Color (Bionk 600 mg/l)
             WESTVACO NUCHAR 8 x 30
                      \
              COD (Blank 690 mg/l -
    
              Color (Blank ITOOmg/l.
              kCOD (Blank 690 mg/l).
    
              »Color (Blank 1750 mg/ll
           800
    
    
           600
    
    
           400
    
    
           200
    
    
           0
           800
    
    
           600
                                                     400 §
           200
    
    
           0
    
           800
    
    
          H600
    
    
           400
                                                         Q
                                                         O)
                                                         LU
                                                     300
            0
    6     8
      pH
                                     10
    12
    14
            R6.4I .INFLUENCE OF pH ON  CARBON
                    ADSORPTION CAPACITY
                              101
    

    -------
    to run these tests on different days, the influent COD and color
    concentrations were different for the tests with Filtrasorb 400
    than with the other two carbons.  Some precipitation occurred in
    tests with Hydrodarco 4000 and Westvaco Aqua Nuchar 8 x 30 at
    pH values greater than 10.0.   The data shown in Figure 41 indi-
    cate that this resulted in additional COD removal for the sample
    adjusted to pH 12.0.  These data show that optimum conditions for
    the removal of both COD and color occur in the region of pH 4
    to 7.
    COLUMN INVESTIGATIONS
    
    Tests Using Activated Sludge Effluent
    
    Activated carbon column tests using activated sludge effluent
    were conducted in 1-in. (2.54 cm) glass columns.  Activated
    sludge effluent from Unit IE and IID operated at an organic
    loading of 0.4 g BOD applied/g MLVSS-day was used as the feed
    for these tests.  Four columns were operated in series at a
    flow rate of 2.5 gpm/sq ft (102 liters/min-sq m).  The system
    was charged with 170 g of carbon at the beginning of each run.
    Carbon was initially contacted with distilled water for 24
    hr to expel air from the pores, then charged to each column
    and backwashed with tap water until a clear effluent was ob-
    tained.  High suspended solids concentrations made it necessary
    to backwash these columns daily.  Prior to backwashing, samples
    were taken from the influent and from the effluent of each of
    the four columns.  Waste was applied to the columns upflow.
    Hydrodarco 4000, Filtrasorb 400 and Westvaco Aqua Nuchar 8 x 30
    were all  tested in the column investigations.
    
    Normalized breakthrough data for these runs on a TSC basis are
    shown in Figures 42 - 44.  Immediate TSC breakthrough for the
    Hydrodarco 400 run was approximately 15 to 20 percent, while
    values for the Westvaco Aqua Nuchar and Filtrasorb 400 runs
    ranged from approximately 30 to 40 percent.  The high immediate
    breakthrough for the Westvaco run might be due to high influent
    total carbon values (approximately 230 mg/1) during the first
    of this run, while average influent TSC values for the other
    two runs  were approximately 120 mg/1.  While the immediate
    breakthrough for the Filtrasorb 400 run was high, the break-
    through did not increase above approximately 40 percent on an
    average basis for the first 800 BV (bed volumes) throughput.
    However,  as will be discussed in the next section, several
    cycles of regeneration in actual use might reduce this initial
    advantage.
                                   102
    

    -------
                2  468  10  12  14  16 18  20 22 24 26  28 30
              ^^^^^^^       TIME (Coys)
    
              0      200     400     60O     BOO    OOO
    
                              THROUGHPUT(8V)
    
    
    FIG42.BREAKTHROUGH CURVE - HYDRODARCO  4000  CARBON
                         «0.04)
                2  4  6  8  10  12  14 16  8 20 22 24  26 28 30
                                TIME (Days)
                                           '    '
                     _       _ _        -
             O      200    400    6OO     6OO     1000
                              THROUGHPUT (BV)
    
     FIG, 43. BREAKTHROUGH CURVE - WESTVACO 8  x 30 CARBON
                             20         X
                                  TiME (flays)
       *-
    6OO   800   1000   I2OO   1400   1600
           THROUGHPUT (BV)
         FIG. 44. BREAKTHROUGH CURVE - FILTRASORB 400 CARBON
                                    103
    

    -------
    Normalized color breakthrough curves for these same tests are shown
    in Figures 45 and 46.   Although no entirely acceptable routine
    method exists for measuring color in industrial wastes, measure-
    ments were made using APHA units since the waste color closely
    matched these standards.   Color breakthrough relationships show
    that the best color removal was obtained with H.ydrodarco 4000
    with progressively less capacity for Westvaco Aqua Nuchar and
    Filtrasorb 400, respectively.  However, it should be pointed out
    that while color breakthrough for the Filtrasorb 400 carbon rose
    above 30 percent after approximately 75 BV throughput, the color
    breakthrough did not rise above 50 percent for any significant
    period during the remainder of the test run.
    
    In order to determine any significant loss of capacity on regenera-
    tion, the spent Hydrodarco 4000 was returned to the manufacturer
    for regeneration.  Subsequently, another test run was made in order
    to compare the performance of the carbon before and after one re-
    generation cycle.  The TSC breakthrough curve for the regenerated
    carbon is shown in Figure 47.  For this test, the adsorption ki-
    netius were very favorable as evidenced by the sharp breakthrough
    approximately nine days after the run was started.
    
    A comparison of the results is presented in Table 11.  These re-
    •sults show that Hydrodarco 4000 exhibited the best removal charac-
    teristics for both COD and color based on a 30 percent breakthrough
    of the influent concentration.  However, the total  COD exhaustion
    capacity to approximately 90 percent breakthrough was greater for
    the Westvaco and Filtrasorb carbon.  Reference to Figure 44 shows
    that while Filtrasorb 400 reached a TSC breakthrough of approxi-
    mately 40 percent very quickly, the breakthrough did not increase
    above 40 percent for an extended period of time.  While the 30
    percent breakthrough capacity for COD was almost identical for the
    virgin and regenerated Hydrodarco 4000 carbon, the 90 percent COD
    breakthrough was significantly greater for the regenerated carbon.
    Because these tests were  run at different times, changes in waste-
    water composition are probably responsible for these differences.
    However, it is possible that enlargement of small pores in the
    carbon upon regeneration  resulted in an increase in the COD capa-
    city.  This might be expected in this case, since organic constitu-
    ents contained in the activated sludge effluent were quite proba-
    bly very large molecules.   While the 30 percent breakthrough
    capacity for color was significantly less for the regenerated
    carbon, this might be due to the particular influent color varia-
    tion at the time of the two tests.   The exhaustion color break-
    through capacities for the two tests were more similar in value.
                                   104
    

    -------
            100
                Influent Color = 400-1200
                 APHA Units
                Carton = 4 columns,
                    170 a/column
                               10  12
                   14  16   8 20  22
                   TIME (days)
    24 26  28  30
              0
    200
                                                  800
         1000
                                400      600
                                   THROUGHPUT (BV)
    
    FIG.45.COLOR  REMOVAL  BREAKTHROUGH CURVES FOR  HYDRO-
            DARCO  4000 AND WESTVACO  8 X30
            (cumAnin-sqmaqpm/8qft xO.04)
          100
           80
           60
           40
           20
              Influent Color =200-800 APHA Units
              Surface Loading = 25 gpm/sqft
              Carbon = l24 a/column, 4columns
                                                 r
                                                    -•-•-**
                                        /  I
    
    
                                       Jl
                                           ;, r
                                       JL
                                             11
                       8    12   16    20   24   28
                                      TIME (days)
                                 32   36   40   44
                                                                 j—u
             0 '  200 ' 400  600  800  1000  1200 1400 1600 1800 2000 220O
                                   THROUGHPUT  (BV)
    
    FIG.46.COLOR REMOVAL BREAKTHROUGH CURVE  FOR  FILTRA-
    
            SORB 400
            (eumAnln-sqm=qpm/sq ft xO.04)
                                    105
    

    -------
       120
       100
        80
     o° 60
       40
        20
    Influent TSC= 75-235 mg/l
    Surface Loading = 2.5 gpm/sq ft
    Carbon = 124 g/Column,  4 Columns
         0
    10     15     20    25     30
                    TIME (days)
                35
    40
    45
    50
         0   200  400  600  800  1000  1200  1400 1600 1800 2000  2200 2400  2600
                                   THROUGHPUT (BV)
    FIG.47.TSC  BREAKTHROUGH FOR  REGENERATED  HYDRODARCO  4000
             (cum/min-sqm = qpm/sqft xO.04)
    

    -------
                              TABLE 11
    
    
    
                      COMPARISON OF RESULTS FOR
    
    
    
                     ACTIVATED  CARBON  ADSORPTION
    
    
    
                     OF  ACTIVATED SLUDGE  EFFLUENT
    Parameter
    30% Breakthrough capacity
    (g COD/g carbon)
    90% Breakthrough capacity
    (g COD/g carbon)
    30% Color breakthrough capacity
    (APHA units x liters throughput]
    (g carbon) (1000)
    Exhaustion color
    breakthrough capacity
    (APHA units x liters throughput'
    (g carbon) (1000)
    Color breakthrough at end of
    run (%)
    Hydrodarco 4,000
    • Virgin
    0.27
    0.44
    
    1.12
    
    1.39
    50
    Regen-
    erated
    0.26
    0.60
    
    0.40
    
    1.25
    75
    Westvaco
    8 x 30
    Oa
    0.60
    
    0.34
    
    1.58
    100
    Filtra-
    sorb 400
    0.01
    0.85
    
    0.13
    
    0.95
    100
    Immediate breakthrough to greater than 30 percent.
                                    107
    

    -------
    Column Tests Using Trickling Filter Effluent
    
    Additional  column tests were conducted in 4-in.  (10 cm) carbon col-
    umns to examine treatment of the trickling filter effluent using
    activated carbon.  The results of these tests are shown in Figure 48
    While a longer contact time might have resulted  in additional
    COD removal, these results might be expected since the trickling
    filter effluent contained considerable concentrations of unde-
    graded low molecular weight solvents which are not readily sorbable
    on activated carbon.
    
    Greater degrees of color removal were achieved in these tests
    showing the greater sorbability of color molecules compared to
    other organic substances in the waste.  Based on color analyses
    using the APHA standards, the Filtrasorb and Hydrodarco 3000
    carbons averaged approximately 50 percent color  removal through-
    out most of this run.   Color removal through the Hydrodarco 3000
    was more erratic, though.  These tests indicate  that further re-
    ductions of gross organics would be necessary in the trickling
    filter system before this combination of treatment processes
    would accomplish much COD removal.  However, if  color removal
    were a major treatment objective, such an approach would be more
    attractive.
                                     108
    

    -------
    ~   1-0
    o
    o
    o
       0.8
    C   0.6
    
    cr
    3   °4
    O
    I
       0.2
     o
    o
    o
        ,8
        0.8
        0.6
    8   04
    
        0.2
    
         0
          0
                                   Surface Loadings 6 gpm/sq ft
                                   Carbon Depth= 3 ft in 4,4 in columns
                 2000     4000     6000     8000
                 .	.      THROUGHfftJT (liters)
      10,000    12,000
          0
                       100
    300
    400
                                          200
                                    THROUGHPUT (Bv)
    RG.48.COD BREAKTHROUGH FOR FILTRASORB 400 USING TRICKLING
           FILTER EFFLUENT
           (cu m/min- sq m= qpm /sq ft x 0.04)
    

    -------
                               SECTION XI
    
            REMOVAL OF ORGANIC CONSTITUENTS BY AIR STRIPPING
    Due to the large proportion of organic solvents in this wastestream,
    the removal of organic substances by air stripping was investigated
    to determine both the incidental removal by this mechanism in bio-
    logical treatment processes and removals which could be obtained
    using air stripping as a unit treatment process.  Preliminary labo-
    ratory experiments in which raw waste was stripped using diffused
    air aeration showed that approximately 75 percent removal of COD
    could be achieved in three days and approximately 92 percent could
    be removed in ten days.   Because no biological inhibitory agent was
    added to the waste during these tests, it is probable that some re-
    moval of organic constituents was achieved by biological  mechanisms.
    However, it seemed unlikely that the major part of the organics
    could be removed biologically during this period in the unseeded
    raw waste.  Based on these results, additional tests were under-
    taken both in the laboratory and on a pilot-scale.
    BATCH LABORATORY-SCALE TESTS
    
    Initially, batch stripping tests were performed in the laboratory to
    determine the degree of organics removal which could be achieved by
    diffused air stripping and to determine the effect of temperature
    on these removals.  Tests were performed in 2-liter graduated cyl-
    inders initially containing 1,000 ml of raw equalized waste.  The
    laboratory compressed air was passed through an oil trap and dif-
    fused through the sample using a porous stone.  Air flows were
    measured using a rotometer.  In order to measure the effect of
    temperature on organics removal, the 2-liter cylinder was partially
    immersed in a constant-temperature bath and the temperature adjusted
    using ice and hot water.
    
    The results of batch experiments run at temperatures of 5, 17, and
    38°C are shown in Figure 49.  While first-order removal of organic
    constituents would be anticipated for individual organic constit-
    uents, the removal of organic carbon in a multi-component system
    would be the summation of removals for individual organic constit-
    uents occurring at different rates.  The semi-logarithmic plot of
    the data in Figure 49 corresponds to these mechanisms, although it
    does not confirm the hypothesis.  Although all tests were not run
    for an extended period of time, it appears from available data that
                                     110
    

    -------
    101
     0
                                   Initial Volume = 1000 ml
                                   Air Flow = 1.2 scfrn
    10
    20
            2468
                            TIME (hr)
    
    FIG.49.TSC REMOVAL IN BATCH STRIPPING  TESTS
            (std. cu m/min = s cfm x 0.028)
    

    -------
    the residual organic concentration at all temperatures tended toward
    a common value indicating the presence of a non-strippable portion
    of organics in the waste.  The greatest removal of total carbon was
    achieved in the 17°C test which was run over a 20-hr period.  The
    total  carbon removal in this case was approximately 80 percent.
    The determination of BOD in this testing indicated that 96 percent
    of the BOD was stripped from the waste in 20 hr.  The residual BOD
    concentration was 130 mg/1.
    
    The effect of temperature on the rate of stripping was correlated
    to the relationship:
    where ks is the stripping waste constant in hr   and T and T1
    are temperatures in °C.  The rate constant, ks, was calculated as
    follows:
    
                      ,         % TSC remaining at t-,
                      Ks	L
    where t] is the time from the beginning of the test in hours.  The
    data correlated according to this relationship is shown in Figure 50.
    These data show that the temperature coefficient, 9, decreased
    with time from a value of 1.043 for the first hour of these tests
    to 1.023 for a 4-hr period.   The value during the first hour of
    1.043 was almost identical  to the value of 1.044 derived from data
    obtained from stripping tests performed with 1-component systems
    of acetone, alcohol, and methyl ethyl  keytone found in the litera-
    ture.  The decrease of the temperature coefficient with time ob-
    served in this investigation would be expected for data obtained
    from batch experiments in which the residual total carbon concen-
    tration after an extended aeration time would be approximately the
    same for a range of test temperatures.
    CONTINUOUS-FLOW STRIPPING INVESTIGATIONS
    Packed Tower Stripping
    
    Stripping was investigated in a packed tower by adding a 2,500 cfm
    (71  cu m/min ) blower to the first pilot trickling filter.  Tests
                                    112
    

    -------
    10
    20
    60
    70
                              30     40      50
                             TEMPERATURE (°C)
    
    FIG.50.VARIATION OF  STRIPPING  REMOVAL COEFFICIENT  WITH
          TEMPERATURE
    

    -------
    were conducted at surface loadings varying from 1  - 10 gpm/sq ft
    (41 - 410 1/min-sq m) and air flows ranging from 300 - 2,500 cfm
    (8.5 - 71 cu m/min).  Results obtained from this investigation on
    a BOD basis are shown as a function of the gas-liquid ratio in
    Figure 51.  The highest BOD removal observed in these tests was
    approximately 60 percent and occurred most consistently at a gas-
    liquid ratio of 500 cu ft/gal (3.75 cu m/liter).  Assuming that
    the stripping action in a continuous-flow system may be approxi-
    mated by a first-order relationship, the data from these investi-
    gations is shown in linearized form in Figures 52  and 53.   The
    mathematical  relationships defining these data may be used to
    estimate BOD and TSC removals for full-scale systems having a
    depth of 20 ft (6.1 m).
    
    Stripping in an Aerated Basin
    
    Additional air stripping investigations were conducted in a 24-ft
    (7.3 m) diameter plastic swimming pool containing  a 1.5 hp surface
    aerator.  The volume of the basin was approximately 13,500 gal
    (51,000 liters) and the applied power level corresponded to approxi-
    mately 150 hp/mil gal (29.5 kw/mi1 liter).   Tests  were conducted at
    detention times of 1.5 and 3 days.  Results of these tests for the
    1.5-day detention time on a chronological basis are shown in Figure
    54.  Total carbon removals of this period averaged approximately
    40 percent.  As an indication of biological activity which occurred
    in this basin, oxygen uptake tests for the influent and effluent of
    the basin were made periodically.  The results of  these tests shown
    in Figure 54 indicate significant biological  activity  in the waste.
    From these data it was estimated that approximately 30 percent of
    the BOD removed in this basin was due to biological mechanisms.
    A summary of results is shown in Table 12.
    
    Chronological data for a 3-day detention time are  shown in Figure 55.
    Because of the relatively high oxygen uptake rates observed in the
    basin, an additional test was run using the 3-day  detention time in
    which 20 mg/1 Cu was added to the basin influent in order to inhibit
    biological growth.
    
    Only one oxygen uptake measurement was made during the period
    June 15 - 30.  This measurement, made near the end of this run on
    June 28, was  52 mg/l-hr.   Oxygen uptake measurements made during
    theperiodin  which copper was added to the basin were 1.0, 6.0,
                                     114
    

    -------
       UJ
       cr
       o
       CD
         100
          80
          60
          40
          20
            0
                  Surface Loading
                   V 10 gpm/sq ft
                   • 5
                   A 2.5
    100
    200     300     400     500
    GAS- LIQUID RATIO, G/L (cu ft/gal)
    600
    700
    FIG.5I .PACKED TOWER AIR STRIPPING RESULTS, BOD  BASIS
            (cu m/min - sq m = gpm/sq ft x O.O4; cu m/cu m = cu ft/gal x 748)
    

    -------
    h-1
    I—1
    ON
                    0.5
                    0.4
                 o
                 CO
                 co  0.3
                o o>
                CO (CO
    
                 CD  0.2
                 o
                    O.I
                     0
                      0
        = 0.894S0IO-(a00056f>
    100
    200   300    400
    
    GAS-LIQUID RATIO
                                                 G. /cu ft N
                                                1 L \ gal I
    500   600   700
         FIG.52. LINEARIZED DATA  FOR PACKED TOWER  STRIPPING
    
                BASIS
                (cu m/cu m = cu ft/gal x 748)
                                               -TSC
    

    -------
     Q
     O
     CD
       0.7
       0.6
       0.5
       0.4
    § 0-3
       0.2
       0.1
        0
          • Total Inf. - Total Eff.
          A Tota Inf. - Sol. Eff.
    Se=Q833 SQIO-(000064
         0     100   200    300   400   500    600   700
    
                     GAS-LIQUID RATIO, ~- ( c" |f
    
    FIG.53.LINEARIZED DATA FOR  PACKED TOWER
           STRIPPING-BOD BASIS
           (cu m/cu m = cu ft/gal x 7.48)
                            117
    

    -------
    I
    LL)
    QC
    O
      2000
    0>
    
    
    O
    1000
    LJ
    CVl
    O
                                      July 2-26, 1973
                                      D.T = 1.5 days
                                 10
                           TIME  (days)
                                          15
     FIG.54.TSC REMOVAL IN AERATED EQUALIZATION
            BASIN -D.T. = 1.5  DAYS
                            113
    

    -------
    I-1
    vo
                                                                                      TABLE 12
    
    
    
                                                                       SUMMARY FOR STRIPPING IN AERATED BASIN
    Detention
    time (days
    3.1
    3.0C
    1 .5
    Temp
    Air Basin
    23
    25
    26
    23
    24
    25
    Flow
    (gpm)<
    3
    3
    12
    TSC(mq/l)
    Inf. Eff.
    1579
    1264
    1327
    548
    522
    804
    TSC | BOD (mg/1)
    Removed1? Total Soluble
    (%)
    65.3
    58.7
    39.4
    Inf.
    6000d
    3565
    4467
    Eff.
    2110d
    617
    2009
    Inf.
    4758
    3685
    4097
    Eff.
    1453
    1435
    1680
    BOD
    removed"
    (X)
    59.8
    82.7
    55.0
    COD (mg/1)
    Total Soluble
    Inf.
    6361
    6240C
    5630
    Fff.
    1990
    2029
    3128
    Inf.
    6100
    --
    4853
    Eff.
    1400
    1740
    2473
    COD
    removed'3
    (SO
    68.7
    53.2
    44.4
    SS (mg/1)
    Inf.
    211
    228
    168
    Eff.
    409
    344
    321
                           dFlow  in  cu/min  =  gpm 3.79 x 10
    
    
    
                             Percent  removals based on total influent and effluent values.
    
    
    
                           GDuring this  period, 20 mg/1 Cu   was added to basin influent.
                             Based  on  one  value.
    

    -------
    o
     60
    
     40-
    
     20
      0
    1800
    |>!200
    o
    H 600h
         0
                                           June 15-30, 1973
                                           D.T = 3 day*
                                            July 21-28,1973
                                            D.T. = 3 days
                                           20 mg/l Cu added
    H	1-
                      1	1	1	h
                                      10
                                                15
                             TIME (days)
      FIG.55TSC  REMOVAL IN AERATED EQUALIZATION
            BASIN-D.T. = 3 DAYS
                             120
    

    -------
    and 24 mg/l-hr for this 7-day test  period.  These measurements  in-
    dicated that biological activity was  significantly  lower during
    this test period, although  the  value  of  24 mg/l-hr  indicates  that
    complete inhibition of microorganisms was not  achieved.  Corres-
    ponding total carbon removal during these two  tests were 59 and
    65 percent, respectively, for tests with and without  the copper
    addition indicating that only slightly reduced removals resulted
    during the tests  in which copper was  added to  the system.  This-
    might be due to a complete  inhibition of the microorganisms or
    to competition between the  stripping  and biological removal mecha-
    nisms.  In the latter case, a greater removal  of organic constit-
    uents due to air  stripping  might be realized under  conditions where
    there is no removal by biological mechanisms.
    
    Removals of BOD,  COD, and TSC observed in these investigations  is
    shown in Figure 56.  The BOD removal  for the 3-day  detention  time
    was significantly less than that which would be predicted from
    corresponding removals of COD and TSC.   The expected  removals, of
    BOD have also been indicated in Figure 56.  Because only one
    valid BOD determination was obtained  from this test,  it is felt
    that BOD removals of approximately  80 percent  would be observed
    on an average basis under these conditions.
    Removal of  Specific  Organic  Constituents
    
    Periodically  during  the  continuous-flow stripping investigations,
    samples were  taken and analyzed  for  solvents.  All samples taken
    for  solvent analysis were made on  a  grab  basis.  A summary of
    these  results appears in Table 13.   These data show very signi-
    ficant removals  of toluene and isopropanol  in both the aerated
    basin  and the packed tower.   Toluene was  completely removed in
    the  stripping processes  for  each observation.
    
    Acetone concentrations increased in  the aerated basin except for
    the  sample  taken on  July 26  during the test in which copper was
    added  to the  basin influent.   Decreases in  acetone concentration
    were observed in the packed  tower  on all  occasions except for the
    the  sample  taken on  July 9.   Data  taken for the packed stripping
    tower  followed by a  biological trickling  filter on July 26 showed
    that acetone  decreased through the stripping tower but increased
    to its original  level in the trickling filter.  These data tend
    to corroborate an observation made in the trickling filter system
    concerning  increases in  acetone  concentration.  Acetone concen-
    trations decreased in the packed tower and  in the aerated basin
                                      121
    

    -------
                        100
    N>
    N5
                                  I       2      3
                                  DETENTION TIME (days)
                FIG. 56 .ORGANIC REMOVALS  IN THE AERATED BASIN
    

    -------
                                                                       TABLE 13
    
    
    
                                                     SOLVENTS  MEASURED IN STRIPPING INVESTIGATIONS
    Process
    Aerated basin
    
    
    
    Packed tower
    
    
    
    Trickling filter
    Following packed
    tower
    Date
    (July 1973)
    9
    12
    23
    26
    9
    12
    23
    26
    
    
    26
    Influent (mg/1)
    Acetone
    300
    200
    200
    400
    300
    200
    200
    400
    
    
    300
    Methanol
    100
    -
    Tr
    400
    100
    -
    Tr
    400
    
    
    200
    Isoproponal
    1900
    1500
    1300
    1600
    1800
    1500
    1300
    1600
    
    
    800
    Toluene
    100
    300
    Tr
    200
    100
    Tr
    200
    -
    
    
    
    Effluent (mg/1)
    Acetone
    700
    500
    400
    200
    700
    100
    100
    300
    
    
    400
    Methanol
    Tr6
    -
    200
    -
    100
    -
    -
    200
    
    
    200
    Isoproponal
    100
    300
    100
    200
    200
    700
    400
    800
    
    
    600
    Toluene
    
    -
    -
    -
    _
    -
    -
    -
    
    
    
    r-o
    uo
                 Tr   =   Trace.
    

    -------
    tests in which biological  growths  were inhibited.   On  the other
    hand, acetone concentrations increased in the aerated  basin before
    copper was added and in the trickling filter following the
    packed stripping tower.   This  indicated that increases in ace-
    tone concentrations  are due to by-products  of biological  degra-
    dation and not to autooxidation of isopropanol  in  the  presence
    of air.
                                  124
    

    -------
                               SECTION XII
    
                            ACKNOWLEDGEMENTS
    This investigation was conducted as a joint effort between  CIBA-
    GEIGY Corporation and Associated Water and Air Resources  Engineers,
    Inc. (AWARE).  The project was sponsored in part by Grant No.  12020
    FOB from the U. S. Environmental Protection Agency and also  by
    CIBA-GEIGY Corporation.  Mr. Robert F. Curran, Director of  Environ-
    mental Technology for CIBA-GEIGY Corporation served as Project
    Director.  Technical aspects of the project were directed by Dr.
    John H. Koon with the consultation of Dr. Carl E. Adams, Jr. and
    Professor W. Wesley Eckenfelder of Associated Water and.Air
    Resources Engineers, Inc.  Technical assistance was also provided
    by Dr. Jan A. Oleszkiewicz.  Mr. David H. Stonefield served as
    Project Officer for the Environmental Protection Agency.  Techni-
    cal evaluation from CIBA-GEIGY Corporation was provided by manage-
    ment and technical personnel of the Cranston Plant.
                                    125
    

    -------
                                SECTION XIII
    
                                REFERENCES
     1.  Chipperfield, P. N. J.  Performance of Plastic Filter Media in
         Industrial and Domestic Waste Treatment.  J. Water Pollution
         Control Fed. 39^ (11): 1860^1874, 1967.
    
     2.  Richard, J. G.  "Design Considerations for Plastic Media Biologi-
         cal Towers," presented at the W. Va. Water Pollution Control
         Assoc 1973 Meeting, April 26, 1973.
    
     3.  Chipperfield, P. N. J., and M. Ashew.  Multiple Stage Plastic
         Media Proving Effective in Treating Biodegradable Industrial
         Wastes.  Ind. Water Eng, August 1970.
    
     4.  Allen, T. S.  Water Reuse in the Food Processing Industry.  Paper
         72^ - PIDrll, ASME,  March 1972.
    
     5.  Chipperfield, P. N., M. W. Ashew, and J. H. Benton.   Multiple
         Stage Plastic Media Treatment Plants.  J. Water Pollution Con-
         trol Fed. 44 (10):1955-1967, 1972.
    
     6.  Oleszkiewicz, J. A., and W. W. Eckenfelder, Jr.  Mechanism of
         Substrate Removal  in High Rate Plastic Media Trickling Filter.
         Vanderbilt Univ.,  Tech. Report, No. 33, 1974.
    
     7.  Bryan, E. H. and D. H. Moeller.  Aerobic Biological  Oxidation
         Using Dowpack.  Advances in Biological Waste Treatment.  New
         York.  Pergamon Press, 1963.
    
     8.  Gulp, G. L.  Direct Recirculation of Trickling Filter Effluent,
         J.  Water Pollution  Control Fed. 35 (6):742-746, 1963.
    
     9-  Weston, R. F.  Fundamentals of Aerobic Biological  Treatment of
         Wastewaters.  Public Works 1^:77-83, 1963.
    
    10.  Velz, C. J.  A Basic Law for the Performance of Biological Fil-
         ters, Sew Wks J. 20_:607-617, 1948.
    
    11.  Sorrels, J. H., and P. J. Zeller.  Heavy Loading on Trickling
         Filters.  J. Water  Pollution Control Fed. 3J5 (9) :1184-1194,
         1963.
                                     126
    

    -------
    13.  Ganczarczyk, J. J. Grabowska.  Limiting Loadings  of  Biological
         Filters (Polish).  Z. N. Politechn Slaskiej,  Inz.  Sanit.  2  1:
         20, 1960.
    
    14.  Rincke, G.  Technology of Plastic Medium Trickling Filters.
         Proc. 5th Int'l Conf. on Hater Pollution Research.  San  Francisco,
         TOT:—	
    
    15.  Germain, J. E.  Economical Treatment of Domestic  Waste Using
         Plastic Media Trickling Filters.  J. Water Pollution  Control
         Fed. 38^ (2):192, 1966.
    
    16.  Eckenfelder, W. W.  Trickling Filter Design and Performance.  J.
         Sanitary Eng Div ASCE.  87^ (SA4):33-45, 1961.
    
    17.  Eckenfelder, W. W., Jr.  Water Quality Engineering for Practicing
         Engineers.  New York, Barnes and Noble, 1970.
    
    18.  Thackston,  E. L., and W. W. Eckenfelder, Jr.   Process Design in
         Water Quality Engineering New Concepts and Development?,  New York
         Jenkins Publishing Co., 1972.
    
    19.  Eckenfelder, W. W., Jr., and Carl E. Adams, Jr.  Process  Design
         Techniques  for Industrial Waste Treatment, Nashville, Tennessee,
         Enviro-Press,  Inc., 1974.
    
    20.  Pearson,  E. A.   Kinetics of Biological Treatment.  Advances in
         Water Quality  Improvement, Vol. ]_, ed. by E.  F. Gloyna and  W. W.
         Eckenfelder, Jr., Austin, University of Texas Press,  1968.
    
    21.  Benedict,  A. H.  and  D.  A. Carlson.  The Real  Nature  of the
         Streeter  -  Phelps Temperature  Coefficient.  Water and Sewage
         Works.   117 (2):54-57,  February  1970.
                                     127
    

    -------
                             SECTION XIV
    
                  LIST OF SYMBOLS AND ABBREVIATIONS
    a       Sludge yield coefficient (g VSS produced/g substrate
            removed)
    
    a'       Assimilative oxygen utilization coefficient (g Op/g
            substrate removed)
    
    b       Endogenous respiration rate (g VSS destroyed/day-g MLVSS)
    
    b'       Endogenous oxygen utilization coefficient (g 09/g MLVSS-
            day)                                          ^
    
    BV      Bed volume; equal to the gross volume occupied by a
            material
    
    C       Concentration (mg/1)
    
    C       Influent concentration (mg/1)
    
    D       Filter depth (ft)
    
    D.O.    Dissolved oxygen
    
    F/M     Organic loading, food to microorganism ratio (g substrate
            applied/g MLVSS-day)
    
    G       Gas (air) flow (cfm) (cu m/min)
    
    k       Activated sludge substrate removal rate constant (1/mg-day)
    
    K       Trickling filter substrate removal rate constant
            ([gpm/sq ft] /ft) (cu m/min-sq m) /m)
    
    L       Liquid (waste) flow (gpm) (cu m/min)
    
    MLSS    Mixed liquor suspended solids
    
    MLVSS   Mixed liquor volatile suspended solids
    
    n       Flow exponent
                                    128
    

    -------
    N        Recycle ratio, N = R/Q
    Q        Flowrate (liters/day or mgd)  (cu m/day)
    Q»       Applied hydraulic loading (gpm/sq ft)  (cu m/min-sq m)
    R        Recycle flow (liters/day or mgd) (cu m/day)
    Rr       Oxygen utilization rate (g CL/day-1)
    SS       Suspended solids
    S        Effluent substrate concentration (mg/1)
    S        Influent substrate concentration (mg/1)
    Sr       Substrate removed, S  = S -S  (mg/1)
    t        Aeration time  (days)
    T,T'     Temperature  (°C)
    IDS      Total dissolved solids (mg/1)
    TSC      Total soluble  carbon (mg/1)
    V        Volume  (liters or mil gal)
    VSS      Volatile suspended solids
    X        Mixed liquor volatile suspended solids (mg/1)
    AX       Excess volatile suspended solids (Ib/day) (g/day)
                                   129
    

    -------
                              SECTION XV
    
    
    
                              APPENDICES
    
    
    
                                                              Page
    
    
    
    A.  Treatment Facility Costs                              131
    
    
    
    B.  Trickling Filter Data Summary                         133
    
    
    
    C.  Activated Sludge Data                                 135
                                  130
    

    -------
                            APPENDIX  A
    
                    TREATMENT  FACILITY  COSTS
    
                               TABLE Al
    
               TREATMENT FACILITY CAPITAL COST SUMMARY3
     Item
                                                             Cost
    Raw waste sump pumps, motors, and bar'screen
    
    Solvent separation tank (50,000 gal,  steel)
    
    Neutralization (vessel, acid and caustic  metering
      pumps, acid and caustic storage tanks)
    
    Nutrient feed (phosphoric acid and anhydrous
      ammonia tank)
    
    Equalization tanks, two (100 ft dia,  20 ft
      SWD, steel)
    
    Pumping through preliminary treatment (pumps
      and motor)
    
    Trickling filters, six (including packing)
    
    Trickling filter fans and motors, s.ix
    
    Trickling filter pumps and motors, six
    
    Clarifier Shell (50 ft dia, 10 ft SWD,  steel)
    
    Clarifier Rake
    
    Sludge Pump
    
    Instruments (including control  panel)
    
    Control building (three offices, conference room,
      laboratory, maintenance area, motor control
      room, equipment and chemical  storage  room)
    
    Site work (including excavation, soil testing,
      and piping)
    
    Engineering
    
    Total
    $   48,800
    
        42,900
    
        17,400
    
    
         4,900
    
    
       416,000
    
    
        26,400
    
    
       540,000
    
         6,600
    
         9,600
    
        52,000
    
        39,000
    
         1,000
    
        32,900
    
       165,000 '
    
    
    
       170,000
    
    
       277,500
    
    $1,850,000
    aCosts are at 1970 levels.
                                  131
    

    -------
                              TABLE A2
    
    
    
             TREATMENT FACILITY OPERATING COST SUMMARY"
    Item
    Supervisory and administrative labor
    (including engineering support)
    Operating labor
    Electricity
    Chemicals
    Laboratory and analytical costs
    Maintenance (labor and materials)
    Yardwork and custodial costs
    Water
    Total
    Cost
    $ 26,000
    67,000
    17,000
    83,000
    26,000
    83,000
    24,000
    1,000
    $327,000/yr
    Costs are for calendar 1973.
                                   132
    

    -------
                                                                       APPENDIX  B
                                                           TRICKLING FILTER DATA SUMMARY
    
                                                                           TABLE B1
                                                                TRICKLING FILTER WEEKLY DATA SUMMARY
    Date
    ii/i
    1 1 / 1
    11/12
    11/19
    11/26
    12/3
    12/10
    12/17
    12/24
    12/31
    1/7
    1/14
    1/21
    1/28
    2/4
    2/11
    2/18
    2/25
    3/4
    3/11
    3/18
    3/25
    4/1
    4/8
    4/15
    4/22
    4/29
    5/6
    5/13
    5/20
    5/27
    6/3
    6/10
    6/17
    6/24
    7/1
    7/8
    7/15
    7/22
    BOD I nig/ 1)
    Inf
    Total
    
    „
    —
    3300
    4313
    4097
    5985
    4545
    4820
    3620
    3460
    2570
    2470
    2997
    4337
    3080
    3558
    2672
    4052
    2273
    3035
    1987
    1258
    1793
    1164
    1870
    1315
    1750
    1747
    1995
    2398
    2598
    4750
    5400
    5227
    3963
    4037
    4060
    Eff
    Total
    
    ,.
    —
    —
    2848
    3177
    5060
    3940
    3280
    2630
    3027
    1797
    2335
    2480
    2893
    2280
    2625
    1850
    2347
    1281
    1447
    1179
    629
    888
    464
    1323
    611
    1031
    1223
    1810
    1753
    2292
    3700
    —
    3153
    2140
    2563
    2170
    Sol
    
    „
    -- •
    --
    2737
    3253
    4200
    3365
    2770
    1750
    2297
    1607
    2155
    2225
    2620
    1950
    2805
    1707
    2450
    1118
    1141
    1056
    414
    582
    355
    1150
    569
    1186
    1160
    1510
    1823
    2263
    3800
    5600
    2930
    2030
    1760
    2500
    ''-
    REM
    
    __
    —
    —
    34.0
    --
    15.4
    13.3
    32.0
    27.3
    12.5
    30.1
    5.5
    17.2
    33.3
    26.0
    26.2
    30.8
    42.1
    43.6
    52.3
    40.7
    50.0
    50.5
    50.1
    29.2
    53.5
    41.1
    30.0
    9.3
    26.9
    11.8
    22.1
    
    39.7
    46.0
    36.5
    46.6
    COD (mq/1)
    Inf
    Total
    A nun
    HUJU
    5048
    3930
    3737
    6030
    Eff
    Total Sol
    
    -.
    2680
    2953
    4237
    6100 4603
    5773 4730
    4957 3175
    5970
    6753
    5233
    4390
    4453
    4707
    5443
    4680
    5107
    4440
    5773
    3507
    4080
    3813
    2647
    3347
    2200
    2600
    2960
    2947
    2960
    2880
    3253
    3371
    6253
    8240
    7147
    6267
    6160
    5760
    4300
    5480
    4000
    3347
    3637
    3120
    3910
    3540
    3947
    2580
    3503
    2387
    2547
    2360
    1485
    1747
    1187
    1928
    2053
    2320
    2507
    2320
    2680
    3133
    4067
    5600
    4707
    3573
    3893
    3353
    once
    cyoo
    3322
    1947
    2737
    3538
    4153
    3493
    2750
    3805
    4587
    3653
    2930
    3240
    2727
    3470
    2980
    3840
    1825
    3147
    2126
    2267
    2200
    1127
    1360
    787
    1784
    1720
    2107
    2403
    2160
    2367
    2963
    3813
    5160
    4320
    3367
    3520
    3107
    %
    REM
    
    __
    31.8
    21.0
    29.7
    24.5
    18.1
    35.9
    28.0
    18.8
    23.6
    23.8
    18.3
    35.7
    28.2
    24.4
    22.7
    41.9
    39.3
    31.9
    37.6
    38.1
    43.9
    47.8
    46.0
    25.8
    30.6
    21.3
    15.3
    19.4
    17.6
    7.1
    35.0
    32.0
    34.1
    43.0
    36.8
    4KB
    TSC(mg/1)
    Inf
    Total
    
    -«.
    1050
    1151
    1716
    1763
    1732
    1016
    1584
    1732
    1543
    1180
    976
    1122
    1348
    2950
    1495
    1337
    1614
    1099
    1037
    888
    807
    892
    727
    748
    940
    842
    857
    659
    786
    800
    1312
    1865
    1644
    1365
    1285
    1253
    tff
    Sol
    
    __
    570
    934
    1291
    1513
    1390
    680
    1233
    1495
    1155
    898
    916
    912
    1018
    2750
    1338
    847
    1013
    744
    668
    629
    500
    547
    296
    545
    695
    691
    729
    660
    689
    785
    841
    1408
    1161
    1007
    991
    912
    % .
    REM
    
    	
    45.7
    18.9
    24.8
    14.2
    19.2
    33.1
    22.2
    13.7
    25.1
    23.9
    6.1
    18.7
    24.5
    6.8
    10.5
    36.6
    37.2.
    32.3
    35.6
    29.2
    38.0
    38.7
    59.3
    27.1 ,
    26.1
    17.9
    14.9
    0
    12.3
    1.9
    35.9
    24.5
    29.4
    26.2
    22.9
    27.2
    Temperature
    :°F}*
    Inf
    
    66
    63
    63
    63
    63
    60
    61
    58
    56
    59
    60
    59
    61
    57
    59
    59
    61
    62
    61
    63
    63
    64
    67
    67
    68
    69
    70
    70
    71
    75
    78
    81
    80
    73
    75
    72
    74
    Eff
    
    52
    61
    58
    58
    58
    58
    57
    56
    50
    57
    57
    56
    55
    52
    54
    53
    59
    62
    57
    63
    60
    59
    65
    66
    63
    63
    62
    63
    69
    72
    77
    73
    75
    82
    81
    82
    81
    Air
    
    46
    40
    41
    36
    33
    33
    34
    37
    14
    40
    38
    26
    31
    30
    35
    30
    45
    49
    36
    41
    44
    39
    58
    57
    54
    54
    54
    55
    67
    70
    77
    70
    70
    78
    79
    77
    78
    Flow
    (mgd)lJ
    1 99
    I . uC.
    1.28
    0.96
    1.07
    1.28
    1.18
    0.85
    0.90
    1.05
    1.15
    1.28
    1.25
    1.21
    1.01
    1.01
    0.72
    0.72
    0.50
    0.50
    0.50
    0.72
    0.72
    0.72
    1.08
    1.03
    0.99
    0.94
    0.99
    1.10
    0.91
    1.15
    0.91
    0.81
    0.94
    0.97
    1.13
    1.10
    0.79
    Loading (lb/
    1000 cu ft-
    dav)c
    BOD
    
    _„-
    —
    491
    767
    672
    707
    569
    703
    579
    616
    446
    415
    421
    609
    308
    356
    186
    230
    158
    304
    199
    126
    269
    167
    142
    172
    241
    267
    252
    383
    329
    534
    705
    704
    622
    617
    446
    COD
    CQA
    OUH
    898
    524
    556
    734
    1000
    682
    620
    871
    1079
    931
    763
    749
    661
    764
    468
    511
    309
    401
    244
    409
    382
    265
    502
    315
    358
    387
    405
    453
    364-
    520
    426
    869
    1145
    993
    871
    856
    801
    Total
    Solids
    (mq/1)
    Inf
    OCl A
    CO 1H
    3114
    2843
    328
    —
    2540
    2650
    3680
    2130
    2125
    3230
    —
    4540
    2210
    2970
    2950
    3012
    2078
    3279
    2639
    —
    4860
    2430
    2390
    2750
    2520
    2388
    2032
    2436
    —
    2144
    1817
    1497
    3694
    —
    3590
    3020
    3420
    Eff
    ?K7T
    t3/ 0
    2828
    2943
    694
    _.
    3000
    2710
    2360
    2260
    £113
    S/828
    —
    2373
    2490
    2730
    2750
    2114
    1884
    3645
    2431
    2225
    2560
    2380
    2780
    2930
    £140
    2133
    2652
    2743
    —
    2244
    2297
    2013
    3505
    —
    3650
    2770
    3670
    SS
    (mg/1)
    Inf
    i -an
    1 JU
    302
    104
    96
    80
    187
    167
    225
    98
    497
    262
    141
    119
    100
    104
    159
    103
    95
    101
    72
    170
    124
    108
    126
    78
    78
    89
    111
    98
    127
    220
    193
    205
    239
    179
    213
    235
    235
    Eff
    t\?
    u£
    37
    104
    71
    99
    97
    126
    69
    83
    272
    143
    129
    120
    159
    113
    105
    91
    84
    205
    134
    96
    137
    126
    187
    232
    129
    105
    132
    89
    99
    152
    155
    121
    122
    156
    143
    164
    145
    VSS
    (mg/ )
    Inf
    
    -,-
    73
    86
    63
    160
    145
    182
    89
    486
    245
    116
    111
    86
    93
    106
    90
    74
    86
    69
    111
    102
    88
    99
    75
    66
    80
    105
    92
    124
    196
    150
    187
    '160
    135
    194
    200
    188
    Eff
    cc
    «JO
    32
    63
    63
    80
    79
    110
    67
    79
    225
    130
    116
    109
    130
    97
    .79
    75
    71
    181
    124
    86
    106
    104
    163
    209
    110
    94
    121
    86
    97
    142
    131
    107
    89
    137
    131
    143
    121
    OJ
              temperature in °C = 5/9 (F-32).
              bFlow in cu m/day = mgd x 4,000.
              °Loading in kg/cu m-day = lb/1,000 cu ft-day x 0.016..
    

    -------
                                     TABLE  B2
    
    
    
                     FULL-SCALE  TRICKLING FILTER  RECYCLE  DATA
    Date
    (1974)
    Apr. 1
    Apr. 8
    Apr. 15
    Apr. 22
    Apr. 29
    May 6
    May 13
    Avg. Air Temp.
    (°C)
    9.4
    6.7
    11.7
    11.1
    13.3
    10.6
    17.8
    Inf. BOD
    (mg/1)
    1,546
    1,492
    1,522
    2,532
    2,351
    2,851
    2,720
    Bank Aa
    Eff. BOD
    (mg/1)
    1,435
    890
    1,453
    1,810
    1,836
    2,555
    2,097
    Removal
    (*)
    7.2
    40.3
    4.5
    28.5
    21.9
    . 10.4
    22.9
    Bank Bb
    Eff. BOD
    (mg/1)
    892
    630
    1,030
    1,537
    1,382
    1,696
    1,472
    Removal
    (X)
    42.3
    57.8
    32.3
    39.3
    41.2
    40.5
    45.9
    Operated at a recycle  ratio of 0.43.
    
    
    
    
    Operated at a recycle  ratio of 2.33.
                                        134
    

    -------
                                      APPENDIX  C
    
    
                                ACTIVATED SLUDGE DATA
    
                                    TABLE  Cl
    
                   SUMMARY OF ACTIVATED SLUDGE RESULTS-PHASE  I
    JNIT
    OPERATIONAL PARAMETERS
    F/M (g BOD/day-g MLVSS)
    Detention time (days)
    MLVSS (mg/1)
    Volume (1)
    D.O. (mg/1)
    Oxygen uptake (g 0£/day-g MLVSS)
    SVI (ml/g)
    ZSV (ft/hr) (m/m)
    Temperature (°C)
    Sludge age (days)
    INFLUENT QUALITY PARAMETERS
    BOD (mg/1)
    Total
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    EFFLUENT QUALITY PARAMETERS
    BOD (mg/1)
    Total
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    SS (mg/1, median value)
    ORGANIC REMOVAL EFFICIENCIES
    BOD (%)
    COD (55)
    BOD removal rate
    (g BODr/day-g MLVSS)
    COD removal rate
    (g CODr/day-g MLVSS)
    IAa
    
    0.22
    5.3
    2620
    151
    6.2
    0.22
    36
    14.7
    17
    15.5
    
    
    3070
    2910
    
    4760
    3980
    7.3
    
    
    77
    54
    
    723
    421
    6.1
    300
    
    98.2
    91.2
    
    0.218
    
    0.314
    IBb
    
    0.084
    11.3
    2410
    151
    6.7
    0.11
    48
    14.4
    17
    32.9
    
    
    2270
    2200
    
    3860
    3500
    7.3
    
    
    15
    14
    
    416
    336
    7.2
    100
    
    99.4
    91.3
    
    0.083
    
    0.130
    icb
    
    0.23
    4.1
    2440
    151
    5.9
    0.23
    39
    24.1
    17
    15.3
    
    
    2270
    2200
    
    3860
    3500
    7.3
    
    
    53
    47
    
    603
    384
    6.6
    214
    
    97.3
    90.0
    
    0.221
    
    0.347
    ID15
    
    0.40
    2.1
    2700
    151
    4.9
    0.45
    33
    19.5
    17
    7.5
    
    
    2270
    2200
    
    3860
    3500
    7.3
    
    
    233
    184
    
    825
    519
    5.9
    302
    
    91.9
    86.5
    
    0.36
    
    0.581
    IEC
    
    0.24
    3.6
    2600
    151
    5.8
    0.26
    40
    13.6
    17
    13.5
    
    
    2220
    2160
    
    3900
    3510
    7.1
    
    
    39
    39
    
    547
    379
    6.3
    182
    
    98.2
    90.3
    
    0.232
    
    0.376
    ?Unit fed raw  equalized waste.
     Unit fed unclarified trickling filter  effluent.
    cUnit fed clarified trickling filter effluent.
                                         135
    

    -------
                                   TABLE C2
    
                SUMMARY OF ACTIVATED SLUDGE RESULTS - PHASE II'
    Influent
    Unit
    OPERATIONAL PARAMETERS
    F/M (g BOD/day-g MLVSS)
    Detention time (days)
    MLVSS (mg/1)
    Reactor volume (1 )
    D. 0. (mg/1)
    Oxygen uptake (g 02/g MLVSS-day)
    Sludge age (days)
    Temp (°C)
    INFLUENT QUALITY PARAMETERS
    BOD, Total (mg/1)
    COD, Total (mg/1)
    Soluble (mg/1)
    pH (median value)
    EFFLUENT QUALITY. PARAMETERS
    BOD (mg/1)
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    ORGANIC REMOVAL EFFICIENCIES
    BOD (%)
    COD (%}
    BOD removal rate
    (g BOD /g MLVSS-day)
    COD removal rate
    (g CODr/g MLVSS-day)
    Unclarified Trickling Filter Effluent
    IIC
    
    0.23
    2.18
    3150
    151
    6.9
    0.28
    16.7
    18
    
    1559
    2096
    1610
    6.9
    
    
    47
    
    365
    261
    7.0
    
    97.8
    87.5
    
    0.22
    
    0.27
    IID
    
    0.43
    1.19
    3020
    151
    6.4
    0.45
    11.4
    18
    
    1559
    2096
    1630
    6.9
    
    
    111
    
    516
    350
    6.9
    
    94.4
    83.3
    
    0.40
    
    0.48
    IIP
    
    0.23
    2.48
    2760
    151
    6.7
    0.31
    22.7
    14
    
    1559
    2172
    -
    7.0
    
    
    44
    
    354
    268
    7.0
    
    96.8
    87.7
    
    0.22
    
    0.28
    Includes data collected  from March  10  to May  26,  1973 except  for  the
    cold temperature operating  period from March  24 through April  13  excluded
    from Unit II F results.
                                        136
    

    -------
                                    TABLE C3
    
    
    
                      SUMMARY OF ACTIVATED SLUDGE  RESULTS,
    
    
    
                     VARIED TEMPERATURE OPERATION  -  PHASE  II
    Influent
    Unit
    OPERATIONAL PARAMETERS
    F/M (g BOD/day-g MLVSS)
    Detention time {days)
    MLVSS (mg/1)
    Reactor volume (1 )
    D. 0. (mg/1)
    Oxygen uptake (g 02/g MLVSSOday)
    Sludge age (days)
    Temp (°C)
    INFLUENT QUALITY PARAMETERS
    BOD, Total (mg/1)
    COD, Total (mg/1)
    Soluble (mg/1)
    pH (median value)
    EFFLUENT QUALITY PARAMETERS
    BOD (mg/1)
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    ORGANIC REMOVAL EFFICIENCIES
    BOD (%)
    COD (%)
    BOD removal rate
    (g BODr/g MLVSS-day)
    COD removal rate
    (g CODr/g MLVSS-day)
    Unclarif led
    Tricklinci Filter Effluent
    IIC
    
    0.130
    2.50
    3260
    151
    6.7
    0.28
    32.3
    17
    
    1107
    2546
    2165
    6.8
    
    
    26
    
    416
    273
    7.0
    
    97.7
    89.3
    
    0.128
    
    0.268
    IID
    
    0.240
    1.50
    3070
    151
    6.6
    0.31
    35.7
    17
    
    1107
    2546
    2161
    6.8
    
    
    49
    
    666
    375
    7.0
    
    95.6
    85.3
    
    0.230
    
    0.471
    IIP
    
    0.142
    4.44
    1750
    151
    9.3
    0.51
    48.8
    6
    
    1107
    2450
    2027
    6.8
    
    
    71
    
    406
    301
    6.8
    
    93.6
    87.7
    
    0.133
    
    0.277
    'includes data collected from March  24  to April 13, 1973.
                                        137
    

    -------
                                  TABLE C4
    
               SUMMARY OF ACTIVATED SLUDGE RESULTS-PHASE IIIa
    Feed*>
    IAe.ratina Gas
    UNIT
    OPERATIONAL PARAMETERS
    F/M (g BOD/day-g MLVSS)
    Detention time (days)
    MLVSS (mg/1)
    Volume (1)
    D.O. (mg/1)
    Oxygen uptake (g 02/day-g MLVSS)
    SVI (ml/g)
    ZSV (m/hr)
    Temperature (°C)
    Sludge age (days)
    INFLUENT QUALITY PARAMETERS
    BOD (mg/1)
    Total
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    EFFLUENT QUALITY PARAMETERS
    BOD (mg/1)
    Total
    Soluble
    COD (mg/1)
    Total
    Soluble
    pH (median value)
    SS (ing/1, median value)
    ORGANIC REMOVAL EFFICIENCIES
    BOD (%)
    COD (%)
    BOD removal rate
    (g BODr/day-g MLVSS)
    COD removal rate
    (g CODr/day-g MLVSS)
    Unstripped
    Air Oxvaen
    III A
    
    0.31
    5.2
    2540
    151
    4.1
    0.35
    55
    17.1
    23
    12.4
    •
    
    4060
    3720
    
    5737
    4972
    8.2
    
    
    134
    99
    
    836
    432
    7.8
    240
    
    97.6
    92.5
    
    0.30
    
    0.40
    III B
    
    0.34
    3.43
    3500
    151
    8.8
    0.46
    37
    15.3
    25
    14.1
    
    
    4030
    3390
    
    5440
    4806
    8.3
    
    
    521
    366
    
    989
    546
    7.1
    280
    
    89.5
    90.0
    
    0.31
    
    0.41
    Stripped
    Ai r Oxvaen
    III C
    
    0.29
    2.4
    2470
    151
    4.1
    0.25
    61
    14.1
    23
    17.1
    
    
    1710
    1440
    
    2484
    2016
    8.3
    
    
    82
    72
    
    373
    320
    7.9
    130
    
    96.3
    87.1
    
    0.28
    
    0.37
    III D
    
    0.32
    2.3
    2210
    151
    8.6
    0.37
    47
    18.0
    25
    28.0
    
    
    1620
    1430
    
    2410
    193S
    8.3
    
    
    51
    47
    
    32]
    276
    7.7
    115
    
    97.4
    88.5
    
    0.31
    
    0.42
    blncludes data  from June  18  to  July 28, 1973.
     All  units fed  raw equalized waste with or without prestripping as indicated.
     First week of  data not included in averages.
                                         138
    

    -------
                                       TECHNICAL REPORT DATA
                                (I'liuse read iHiilruciions on the reverse before completing)
    , REPORT NO.
                                                                3. RECIPIENT'S ACCESSION-NO.
     .ITLE AND SUBTITI. E
     Evaluation  and  Upgrading of a Multi-Stage Trickling
     Filter Facility
                   !3. REPORT DATE
    
                    December  1976 (Issuing date)
                   6. PERFORMING ORGANIZATION CODE
     .AUTHOR(S)
     Koon, John  H.;  Curran, Robert F.;  Adams, Carl E. Jr.;
     and Eckenfelder, W. Wesley, Jr.
                   8. PERFORMING ORGANIZATION REPORT NO.
    9. PERFORMING ORG \NIZA I ION NAME AND ADDRESS
      AWARE  under contract to:
    
      CIBA-GEIGY  Corporation
      Cranston, RI
    12. SPONSORING AGENCY NAIWf AND ADDRESS
      Industrial  Environmental Research  Laboratory - Cin., OH
      Office  of Research and Development
      U.S.  Environmental Protection Agency
      Cincinnati,  Ohio  45268
                   10. PROGRAM ELEMENT NO.
    
                      1BB036;  Roap 21AZO
                   11. iSfflCKiXdiJXr/GHANT NO.
    
                      12020 FOH
                   13. TLYPE Qf; REPORT AND PERIOD COVERED
                       inal
    hi
                   14. SPONSORING AGENCY CODE
    
                     EPA/600/12
     15. SUPPLEMENTARY NOT IS
     16. ABSTRACT
     The  applicability of a full-scale,  six-stage trickling filter  plant  was  investigated
     for  the  treatment of waste from a multiproduct organic chemical  plant.   Reductions
     of BOD per unit volume of nacking indicated that the series design of the system
     did  not  lead to stage-wise acclimation  of the microorganisms or  enhanced BOD removals.
     Tests  to determine BOD removal mechanisms in the system indicated that air stripping
     and  biological  mechanisms both contributed significantly to the  total observed re-
     duction.  Effluent recycle considerably improved filter performance.  However, 600
     percent  recycle was required for an  approximate 90 percent reduction of  BOD at a
     hydraulic loading of 2 gpm/sq ft (0.08  cu m/min-sq m).  Bench-scale  activated sludge
     investigations  showed that this process could be used successfully for upgrading
     the  trickling filter system.  Kinetic parameters necessary for the design of activated
     sludge systems  were determined.  Comparative studies of air and  oxygen aeration in-
     dicated  that the treatment of wastes containing volatile substances  might be diffi-
     cult in  a closed oxygen system.  Activated carbon adsorption,  also tested in small-
     scale  systems,  was most effective as a  means of upgrading the  trickling  filter
     system when applied following activated sludge treatment.  Activated carbon tests
     indicated that  some refractory organics and color-producing substances could be
     effectively removed by adsorption; however, a significant nonadsorbably  organic
     fraction remained.
    17.
    
    a.
                                    KEY WORDS AND DOCUMENT ANALYSIS
                      DESCRIPTORS
     *TnckTTn'g  Filters,  *BioTogicaT Treatment,
     *Activated  Sludge, *Chemical Wastes,
     Chemical  Treatment,  Adsorption, Industrial
     Wastes, Monitoring,  Waste Water Treatment
    13. DISTRIBUTION STATEMENT
     Release to public
      b. IDENTIFIERS/OPEN ENDED TERMS
       *Air Stripping,  *0rganic
        Chemical  Industry
      19. SECURITY CLASS /Tills Rejxin/
        Unclassified     	
      "20. SECURITY CLACB (This pdge)
        Unclassified
                 COSATl Field/Group
                   13/B
                                                                              21. NO. Of PAGES
                     151
    CPA Form 2220-1 (9-V3)
    
    
      •fr U.S. GOVERNMENT PRINTING OFFICE: 1977-757-056/5525 Region No. 5-H
    139
    

    -------