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25
-------
TABLE Z-5
INSTRUMENTATION OF PLANT PROCESSES
AND WASTE STREAMS
Instrument
Locations
Parameters Measured
Conductivity Meter
Density Meter
gamma radiation
ultrasonic
D.O. Meter
membrane electrode
Flow Meter
flume, venturi,
magnetic, weir
Gas Analyzers
Oxidation-Reduction
Potential (ORP) Meters
pH Meter
Selective Ion
Electrodes
Total Organic Carbon
(TOC) Analyzer
Industrial discharge
Primary effluent
Final effluent
Aeration basins
Clarifier underflow
Conditioned sludge
Anaerobic digesters
Aeration basins
RBC stages
Final effluent
Raw wastewater
Sidestream flows
Return/waste sludge
Chemical feed
Final effluent
Collection system
Confined spaces
Aeration basin off-gas
Industrial discharge
Primary effluent
Industrial discharge
Collection system
Raw wastewater
Aeration basins
Anaerobic digester
Final effluent
Industrial discharge
Primary effluent
Final effluent
Industrial discharge
Raw wastewater
Primary effluent
Final effluent
Metals,
Dissolved solids
MLSS
Solids concentration
Dissolved oxygen,
Flow rate
CO, C02, CH4, H2S
Oxygen transfer
Metal forms
Acids, Bases
Cl~, CN~, Cu+, Cu++, F",
NH3, NO', Pb++, S
Organic slugs,
oil and grease
Source: James M. Montgomery, Consulting Engineers, Inc.
26
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TABLE 2-6
ANALYTICAL MONITORING OF PLANT PROCESSES
Process
Clarification
Activated Sludge
Trickling Filters
RBCs
Parameters
Dissolved oxygen
Sludge solids content
Sludge "blanket depth
Dissolved oxygen
Mixed liquor suspended solids
Oxygen uptake rates
Microscopic examination
Nutrients
Sludge volume index
Slime thickness
Influent pH, temperature, H^S
Effluent solids content
Dissolved oxygen (each stage)
Soluble BOD (each stage)
Biomass thickness
Shaft weight
Effluent solids content
Testing
Frequency
Daily
Weekly
Daily
Daily
Daily
Daily/Weekly
Daily/Weekly
Daily/Weekly
Daily
As needed
As needed
As needed
Daily
Weekly
As needed
Daily/Weekly
As needed
Anaerobic Digestion
Temperature
Solids content
Metals content
Volatile acids/alkalinity
Supernatant solids, NH3
Methane content of gas
Daily
Weekly
Weekly/Monthly
Daily
Weekly
Daily
Source: James M. Montgomery, Consulting Engineers, Inc.
27
-------
TABLE 2-7
METHODS FOR EVALUATING INHIBITORY EFFECTS
OF INDUSTRIAL WASTEWATERS
1.
2.
3.
4.
Method
BOD Serial Addition
Respirometry
Packaged Bacteria
Photo Luminescense
Testing Time
5 days
30-60 min.
30-60 min.
15 min.
Approximate
Equipment Costs
$1,000
$1,000 - $5,000
$1,000 - $2,000
$5,000 - $10,000
Operator
Training
2-4 hrs.
4-8 hrs.
4-8 hrs.
20-40 hrs.
Source: James M. Montgomery, Consulting Engineers, Inc.
28
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3. SOURCE IDENTIFICATION
There are two aspects of source identification that should be considered by
POTWs when investigating interference problems:
specific causative pollutants
industrial source(s) of the pollutants identified
The ease with which a causative agent is identified depends upon the nature of
the permit violation. For example, if the interference results from the inability
to dispose of sludge, the problem nearly always results from an unacceptable
concentration of a particular heavy metal. However, if the plant effluent has a
BOD above the permit limit, the problem can range from a shock loading of
influent BOD to an inorganic or organic pollutant that is toxic to the biological
population in secondary treatment. Isolated spill events are difficult to trace to
a specific pollutant unless the pollutant is detected in routine influent and
effluent screening or the spill is accompanied by distinct, recognizable odors,
appearance, pH or solid residues. Recurring discharges may be linked to a
substance with time by process of elimination and analytical testing.
Once an interference is linked to a specific pollutant, the next step is to identify
the industrial source. If the POTW has sufficiently charcterized its industrial
users as part of its initial pretreatment program development, this task will be
greatly simplified. As part of the development of a federally-approved pretreat-
ment program, POTWs are required to conduct a survey of industrial users to
characterize their wastes. The POTW should be familiar with each ITJ's
industrial processes and the chemicals which are used, produced, stored,
disposed, or otherwise handled on the site. The potential for intentional or
accidental discharge of pollutants should be evaluated. The IU survey informa-
tion should be updated at least annually. Another approach to identifying
industrial sources is a tracking program that monitors the interfering pollutants
at key interceptors and traces the substance back to its discharge point.
While industries are sometimes responsible for POTW permit violations, the fault
can be with operation and maintenance practices at the POTW. Where plants
experience chronic operational problems that cannot be linked to industrial
waste discharges, the plant staff may wish to conduct a Composite Correction
Program (U.S. EPA, 1984) to identify operational problems. If violations persist,
then a more comprehensive search for industrial sources is justified. The CCP
was developed by the U.S. EPA as a means to provide "information on methods to
economically improve the performance of existing POTWs". It outlines an
approach for POTW personnel to evaluate POTW operations and implement
systematic improvement steps.
29
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3.1 CHRONIC DISCHARGES
Industrial waste monitoring is the key to successfully identifying most chronic
industrial waste sources. Industries should be monitored for conventional
pollutants, with the testing of other compounds determined by the nature of the
specific industrial waste. In the case of categorical industries, some substances
of concern and pretreatment requirements are already specified by the
regulations. For noncategorical industries, information such as permit
applications and questionnaire responses or specific analytical testing of industry
effluent should provide sufficient data to establish a monitoring program.
Sewer use ordinances and industrial waste management programs typically
provide for some means of monitoring an industry's discharge to the municipal
collection system. Such ordinances require measurements of both quantity and
quality of the industrial or combined domestic/industrial flow. Industrial
discharges are usually monitored both by industry, with regular self-reporting
requirements, and by the municipality.
If it has been determined that a plant upset is being caused by industrial wastes
and is not a result of other POTW deficiencies, then it is up to POTW personnel
to identify the specific source of that upset. This may necessitate expansion of
the POTW's monitoring program as discussed in the next subsection. POTWs
experiencing interference problems tend to fall into one of three categories
regarding interference:
1. A single major industry in town dominates the waste characteristics
at a relatively small POTW.
2. One or two industries among several are primarily responsible for
waste strength fluctuations in small to medium-sized POTWs.
3. Industrial wastewater from numerous sources controls the waste-
water feed characteristics, with no single dominant industry.
The first category listed above is by far the easiest situation to deal with from
an identification standpoint. By monitoring the industry's discharge, POTW
influent and effluent and other relevant plant operations, the impact of the
industrial waste on the POTW can be determined. The cities of Oswego, New
York and Tolleson, Arizona are examples of small facilities significantly
impacted by a single industry.
Category two is a more difficult interference to trace. A monitoring program
may be sufficient if a large database exists covering a period of time.
Unfortunately, when numerous industries must be tested on a frequent basis, the
sampling and analysis costs can be high. Routine sampling for all industries with
additional sampling for troublesome industries may provide a solution for some
POTWs. For example, Paris, Texas set up a comprehensive short term (90 day)
sampling program that industry supported financially. Through this effort, Paris
was able to distinguish which industries were likely to be problems and then
could adjust their long-term sampling accordingly.
30
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The third category generally applies to larger facilities which are less likely to
be susceptible to any particular industrial effluent. Baltimore, Maryland and
Passaic Valley, New Jersey are examples of facilities which fit into this third
category, but have experienced interference (see Appendix A). Large plants may
be less likely to experience permit violations due to industrial waste, but they
have frequently experienced inhibition and other operational and maintenance
problems. Intermittent discharges are particularly difficult to pinpoint by POTW
personnel because of large service areas.
3.1.1 Routine Monitoring
In order to have the ability to utilize POTW influent characterization to identify
the source of interfering pollutants, adequate background and supporting infor-
mation must be available to POTW personnel. A database obtained over several
years of routine monitoring enables a POTW to develop action level criteria for
key parameters. When monitoring shows that these criteria have been exceeded,
it can be suspected that a spill or unauthorized discharge of industrial waste has
occurred, which triggers a tracking program. Specific details of industrial
monitoring programs have been outlined by EPA and others (EPA, 1983; WPCF,
1982).
Routine compliance monitoring, which is part of any local industrial waste
control program, will sometimes serve to generate an adequate background
database. However, POTWs which have interference problems may need to
perform additional monitoring until the source of the problem can be identified.
For compliance monitoring purposes, monitoring methods and frequency are
generally specified by each municipality in its pretreatment program documents
or sewer use ordinance and in discharge permits, contracts or orders issued to
industrial users. Self-monitoring by industry with monthly checking by the
municipality enables the POTW and the industrial users to share the expenses of
monitoring. Such an approach is most successful when:
key manholes or representative sampling points are available
sampling procedures are clearly outlined and followed
a qualified laboratory performs the analytical testing
rigorous reporting requirements are established for the industries
spot checking by the municipality is performed on a frequent yet
random basis
The alternative to self-monitoring is for a municipality to perform all sampling
and analytical services on a once-per-month or once-per-quarter basis, depending
on the significance of the specific industry to the POTW. Under this scenario,
split samples should be made available to the industry, if requested, to provide
them with the opportunity to verify the test results from which their compliance
status and user fees will be determined. Many municipalities prefer not to place
major reliance on industrial self-monitoring for compliance determinations; they
are able to recover the costs for their monitoring programs by assessing fees for
industrial discharge permits or by directly billing the sampling costs to the
industrial user.
31
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Regardless of the approach taken, the objective of any industrial monitoring
program is to obtain representative analytical results of the wastewater flow and
characteristics. An industry with highly variable quality and quantity should be
sampled more frequently than one with a consistent effluent quality. An
appropriate sampling schedule or discharge schedule for batch processes should
be determined for the industry.
If industrial wastes have been well characterized and adequately monitored, then
the identification of an interfering or potentially interfering pollutant source
will be facilitated. As an example, if a POTW suspects a change in their influent
wastewater characteristics by observing a change in one or more operational
parameters, this triggers influent sampling. The interfering pollutant and
concentration are determined through analytical testing, which is then compared
with the information from the monitoring database to identify industries that
discharge (or have the potential to discharge) the problem pollutant. In some
cases, especially large sewer systems, it is not easily determined which of many
industrial contributors is responsible for a particular pollutant that is causing an
interference. However, several large POTWs including Baltimore, Maryland and
Hampton Roads, Virginia have experienced success after setting up their
monitoring programs. It has even been suggested that the mere fact that they
set up a program motivated some industries into cleaning up, rather than risking
the consequences. Those large POTWs that have put effort into their monitoring
program have been successful.
3.1.2 Tracking Program
A tracking program is a procedure developed for locating the source(s) of a
pollutant or impact which has been identified at a POTW. Depending on the size
of the POTW, the sewer system and the type and number of industrial users, this
procedure may be very simple or rather complex. A small system with only a
few industrial contributors will probably not require anything more than a
procedure for comparing POTW influent sample characteristics with industrial
monitoring results. On the other hand, large systems may require sophisticated
programs involving computer analysis.
The City of Baltimore has a computer program that attempts to trace
contaminants back to the source, knowing the necessary background data (see
Appendix A). Batch printouts, called the "Daily Average Mass Discharge
Reports," provide monthly listings of companies grouped by sewer service area
and chemicals used, stored, and/or discharged. If a chemical compound (such as
a solvent) can be identified by the tracking team, or later by means of sample
analysis, a search of the Data Management System's batch printouts can identify
possible industrial sources.
Rapid toxicity testing procedures may become valuable tools for identification
of interference sources as they gain acceptance by municipalities. A toxic
impact can be traced upstream through a collection system very rapidly when
the test procedure takes less than 30 minutes. Such a system has been used at
Baltimore's Patapsco Plant to identify influent toxicity problems. This approach
to interference tracing is most useful if the troublesome industry discharges
32
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toxicants. Municipalities must continue to rely on more conventional monitoring
practices for upsets resulting from non-toxic contamination.
One of the most comprehensive tracking programs is maintained by the Hampton
Roads Sanitation District (HRSD) in the Tidewater area of Southeastern Virginia.
The HRSD operates nine treatment plants handling 130 million gallons per day
generated over a service area covering 1,700 square miles. Industrial wastes
from 300 sources are dominated by military installations, with other significant
discharges from manufacturing and food processing. Industrial discharges are
categorized according to which of the following methods of tracking is
employed:
sensory observations
measurements with field equipment
sampling and analysis
For the first two types of tracking methods, the HRSD has personnel on stand-by
duty supplied with radio equipped vehicles and extensive field sampling and lab
equipment capable of qualitative, as well as quantitative, analyses. Tracking
begins by HRSD personnel checking pump stations and sewer lines in a
downstream to upstream fashion until the source is isolated. Along the way
samples are collected, labeled and preserved as evidence.
For the third type of tracking method, automatic sampling equipment is set up at
key locations throughout a service area. The samples are collected each day and
analyzed. After pollutant concentration trends are determined, the samplers are
moved upstream. This general procedure is continued until the source of the
problem is found.
In either case, once the source(s) is located, the industry is contacted directly
and actions taken appropriate to the circumstances. All costs associated with
the investigation, clean-up and any other item are billed directly to the source.
The HRSD has found that just by having a. highly visible industrial waste
investigative team, users are deterred from unauthorized discharge to the sewer
system. As a result, incidences have decreased by more than 50 percent in the
last eight years.
Tracking programs such as HRSD's are most successful at tracking chronic
discharges. Although not as easily accomplished, isolated spills and unauthorized
slug discharges of short duration can be tracked if quick, aggressive action is
taken. The next section discusses isolated spills in more detail.
3.2 ISOLATED SPILLS AND UNAUTHORIZED DISCHARGES
Interference-causing materials frequently enter POTWs as spills and
unauthorized discharges. The sources generally fall into one of the following
categories (Busch, 1986):
transportation accidents or leaks
storage tank or transfer pipe leaks
industrial discharges
33
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industrial accidents
fires in warehouses and commercial operations
waste haulers
midnight dumpers
The focus of this manual is on industrial discharges, industrial spills, and waste
hauler discharges (both legal and illegal), because these are the problems over
which the POTW usually has the most control. However, POTWs may be able to
control some of the other problems listed by extending the spill prevention and
control plan procedures described in this manual to any business that has toxic or
hazardous materials on site. The POTW would have to assess its legal authority
to set up this type of comprehensive program.
The extent of the spill and illegal discharge problem in POTWs is severe. In the
spring of 1985, the Association of Metropolitan Sewerage Agencies (AMSA)
surveyed 107 of their member municipalities concerning hazardous waste
discharges to their facilities. The respondents to the survey represent
308 POTWs, corresponding to 39 percent of the estimated total flow and
47 percent of the estimated industrial flow nationwide. The results of the survey
indicated that hazardous wastes, if improperly discharged, can have serious
effects on POTWs. Specifically, the survey showed:
nearly all POTWs receive hazardous wastes
the most commonly discharged wastes are corrosives, solvents,
electroplating baths and sludges
the most commonly reported sources of these wastes are spills,
illegal discharges from industries and routine discharges from indus-
tries
half of the respondents indicated the discharge of explosive or
flammable materials (gasoline, toluene, naphthalene, benzene,
xylene, jet fuel) and nearly half reported corrosion of the sewer lines
due to acids and hydrogen sulf ide gas
approximately 30 percent of the respondents have experienced one or
more biological treatment system upsets since 1980 resulting from
the presence of metals, cyanide, diesel fuel, toluene, paint thinner or
stripper, iodine, thiocyanate and pesticides
It is clear that slug discharges resulting from spills, batch releases, dumps, and
illegal discharges are a common concern for many POTWs. It is the responsibi-
lity of industry to notify a POTW of a slug discharge under federal regulations
(40 CFR Part 403.12(f)). The regulations describe a slug loading as any pollutant,
including oxygen-demanding pollutants (BOD, etc.), released in a discharge at a
flow rate and/or pollutant concentration which will cause interference at the
POTW. However, POTWs do not always receive proper notification. One POTW
(HRSD) has responded to slug loads by contacting its major industries in the
service area immediately upon detection. This action is taken for the following
reasons:
34
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1. an IU may not be aware that it is causing a problem;
2. it brings the problem to industry management attention;
3. it provides visibility for the POTW's control program;
4. it discourages illegal discharges;
5. if the problem is later tracked to an industry, the fact that the
industry was notified of the problem immediately may stengthen
enforcement proceedings against an uncooperative industry; and
6. there may still be time to correct the problem.
The mitigation efforts described in Section 4 related to industrial spills focus
mainly on prevention measures and in-plant corrective measures that are best
implemented if proper notification is received by the POTW. The use of
permanent gas detection equipment in sewer lines or treatment plant headworks
is a method of detecting certain types of pollutants that does not rely on
industry notification.
Tables 3-1 and 3-2 provide some examples of industrial spill incidents as
documented by Busch (1986) and Attachment 2 of the AMSA survey report.
3.2.1 Hauled Wastes
Identification of a waste hauler as the source of an interference is sometimes a
difficult task. Hauled wastes can be discharged to convenient manholes and the
hauler gone before the waste reaches the POTW. There are examples where
hazardous waste haulers have paid industries for the seclusion their facility
provides during such illegal discharge events. Approaches used to help alleviate
the problem include:
periodic sampling of suspected sewer lines
surveillance of waste haulers and suspected discharge points
education of industries concerning the seriousness of these violations
increased public awareness of illegal dumping
increased enforcement
Many states have enforcement programs to assist POTWs in detecting illegal
discharges. Local law enforcement officials can also be requested to assist in
surveillance activities and enforcement. Video surveillance of suspected
manholes or storm drains is also a possible option. Some POTWs use locking
manholes to discourage illegal dumping at suspected sites.
Table 3-3 gives examples of the impacts of hauled wastes on both the collection
system and treatment plant in cities identified through the AMSA survey. A
number of problems indicated by the AMSA survey showed the source as
"unknown", which is indicative of the problems associated with tracking hauled
waste interferences. In the Louisville, Kentucky example given in Table 3-3, the
waste hauler discharged the hexachloropentadiene to a manhole located within a
tobacco warehouse (Busch, 1986).
35
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Interference can also occur when hauled wastes are discharged legally to
treatment plants. POTWs that accept discharges of hauled waste should
establish control procedures to ensure that the wastes are compatible with
treatment processes. Procedures for regulating waste haulers are discussed in
Section 4. Identification of a waste hauler as the source of interference can be
facilitated by employing such measures as:
restricting hauled waste disposal to designated, monitored sites in the
collection system or at the treatment plant
permitting waste haulers
requiring submission of a tracking form that documents the origin,
transportation, and disposal of the waste
sampling hauler loads (samples only analyzed if there is a plant
impact)
permitting, sampling, and inspecting the waste generator
Submission of a tracking form, called a waste manifest, is already a federal
requirement when haulers are discharging hazardous wastes. The Resource
Conservation and Recovery Act (RCRA) places requirements on hazardous
wastes received by truck, rail, or dedicated pipeline into POTWs. It is important
that POTW operators become aware of these RCRA requirements and the need
to coordinate their local procedures for accepting hazardous wastes with State
and EPA personnel. To provide information and guidance on the RCRA
hazardous waste requirements and their implications for POTWs, EPA has
published a manual titled RCRA Information on Hazardous Wastes for Publicly
Owned Treatment Works (EPA, 1985c).
3.3 RAPID SCREENING TECHNIQUES
Once an interference is suspected, a number of rapid chemical tests, available
from chemical supply houses, can provide preliminary indication of the presence
of substances thought to be producing the interference. These tests help
determine in seconds the need for more thorough quantitative analysis and
tracking. In addition, these screening tests are also useful when evaluating the
loads of waste haulers at dumping stations (Section 4.Z.4).
1. Metals Chemical test strips utilizing color change indicators may
be used to detect the presence and concentration of specific metals.
2. Solvents Gas detection tubes, sensitive to gases and vapors, can
indicate the presence and concentration of solvents, but may not be
reliable for determining the specific solvent type due to chemical
interferences among similar-type solvents. A portable hand pump
draws in a calibrated amount of air through the detector tube, and
the amount of color change indicates the concentration.
36
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3.4 SUMMARY
Source identification is the key aspect of any industrial waste management
program. Identifying the source(s) of interference-causing substances being
discharged from a variety of industries is not an easy task and must be
approached with an aggressive, well conceived program if it is to be successful.
There is no simple step-by-step procedure to follow to efficiently identify the
source of every interference problem. However, a rational approach to the
problem can be employed for some interferences which can minimize the effort
required. Figure 3-1 is a flow chart that suggests a possible approach to dealing
with permit violations or upsets. It basically outlines steps to be taken at the
treatment plant to identify possible pollutants causing problems. Figure 3-2 is a
flow chart developed by the HRSD that outlines the steps they take in the event
that the treatment plant is upset or unusual influent is detected. It must be
recognized that each POTW presents a unique management and operations
structure to go along with process variations. Therefore, it is important to
realize that Figures 3-1 and 3-2 are only examples, and not necessarily
applicable to all POTWs. The most important aspects of any source
identification or tracking program are well thought out procedures coupled with
an aggressive approach to enforcement.
37
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TABLE 3-1
INDUSTRIAL SPILLS OF HAZARDOUS MATERIALS:
IMPACT ON SEWER COLLECTION SYSTEM
City
Akron, OH
Bayville, NJ
Bergen, NJ
County
Bloomington, IN
Dayton, OH
Forth Worth, TX
Hillborough, FL
Jacksonville, FL
Los Angeles, CA
County
St. Paul, MN
Toledo, OH
WSSC, MD
Industry
Rubber Mfg.
Pharmaceutical
Water Treatment
Grain Processing
Electroplating
Food Processor
Gasoline Station
Battery Salvaging
Organic Chemicals
Petroleum
Refining
Metal Finishing
Adhesives
Photofinishing
Pollutants
Naphtha, Acetone,
Isopropyl Alcohol
Sulfides from
high BOD
High and low pH
Hexane
Acids
Gasoline
Acids
Solvents
Sulfides
Acids
Glue
Sodium Bisulfite,
low pH
Impact
Explosion
Corrosion
Corrosion
Explosion
Corrosion
Explosion
Corrosion
Corrosion,
Odors
Corrosion
Corrosion
Plugged
Sewers
Corrosion
Sources: Busch (1986), AMSA
38
-------
TABLE 3-2
INDUSTRIAL SPILLS OF HAZARDOUS MATERIALS:
IMPACT ON TREATMENT PLANT
City
Industry
Pollutants
Impact
Boise, ID
Camas, WA
Camden, NJ
County
Dallas, TX
Depue, IL
Electroplating
Pulp Mill
Dye Mfg.
Fertilizer Mfg.
Cu, Ni, Zn
Chlorine
Aniline
Organic Chemicals Xylene, Toluene
Sulfuric Acid
Reduced
treatment
efficiency
Biological
upset (2 days)
Biological
upset, sludge
contamination
Fouled carbon
scrubbers
Biological
process wiped
out
Sources: Busch (1986), AMSA
39
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TABLE 3-3
IMPACTS OF WASTE HAULER DISCHARGES ON POTWs
City
Pollutants
Impact
Central Contra Costa, CA
Louisville, KY
Rockford, EL
San Diego, CA
Solvents
Hexachloropentadiene
Electroplating sludge
Cd, Cr, Pb, Zn, CN~
Gasoline
Biological process
wiped out
Treatment plant
out of operation
for 3 months
Hydrogen cyanide
gas production
potential
Sewer explosion
Source: U.S. EPA (1986a)
40
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TRACE TO
SOURCE
IMPROVE
PLANT
PERFORMANCE
SAMPLE
IMPROVE
PLANT
PERFORMANCE
f.
S AND
LL.ENT
TRACE TO SOURCE
ENFORCE
LOCAL LIMITS
SAMPLE POTW
UNIT
PROCESSES
COMPOSITE CORRECTION
PROGRAM (SEE TEXT, PAGE 29)
SOURCE:
JAMES M. MONTGOMERY,
CONSULTING ENGINEERS. INC.
TRACE TO
SOURCE
FIGURE 3-1
TREATMENT PLANT UPSET IDENTIFICATION PROCEDURES
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Supervisor inspects
treatment plant &
phones key industries
to check for spills
Samples collected,
labeled & preserved
during tracking
process
Costs involved with
treatment plant
upset billed to
industry
Supervisor contacts
Coast Guard and/or
State Water Control
Board if pass-through
is evident
IU permit changed to reflect
new monitoring requirements
& compliance schedule
If discharge not
stopped, permit
suspended for up to
60 days to stop all
industrial waste-
water discharges
IU permit modified
to reflect compliance
schedule Sc possibly
increased monitoring
requirements
Water and/or
wastewater service
may be terminated at
this time or later
FIGURE 3-2
HRSD SOURCE TRACKING PROCEDURE
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4. MITIGATION
Mitigating an interference is the goal following the detection of an interference
problem. Whether source identification precedes mitigation depends on the
success of the POTW's tracking program, its knowledge of its lUs, and the other
issues discussed in Section 3. In certain cases, interim measures to address
interference can be taken without initially defining the interfering pollutant
substance or source, although this information can be very helpful. However,
even if an isolated interference event can be handled by process modification at
the treatment plant, the source of the interfering discharge should be identified
and controlled. Interference mitigation by pretreatment and source control or
legal and enforcement remedies obviously requires information about the
discharger(s) causing the problem, but results in a more reliable solution.
The success of any effort to mitigate interference is dependent to a great extent
on the characteristics of the pollutants causing the interference, the charac-
teristics of the treatment plant (capacity, capacity utilization, biological
process, etc.) and the type(s) of mitigation attempted. It is important to
emphasize that mitigation of an interference problem is generally not a
straightforward process. Each POTW possesses unique characteristics that
exclude generalized solutions or approaches so that a combination of techniques
is often necessary to realize satisfactory results.
4.1 TREATMENT PLANT CONTROL
The effects of industrial pollutants on a typical POTW can be eliminated or
minimized through a number of measures initiated at the treatment plant, often
in combination. They can be generally categorized as:
biological process control
biological augmentation
chemical additions
operations modifications
physical modifications
The list above is generally in order of increasing implementation difficulty, e.g.,
biological process control generally requires only minor changes in plant opera-
tion while physical modifications can include costly capital improvements.
4.1.1 Biological Process Control
Biological process control is generally limited to activated sludge systems,
although some modifications to fixed film processes (e.g., trickling filters,
rotating biological contactors) might be considered as a form of biological
43
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process control. An activated sludge system is generally monitored or controlled
by utilizing one or more of three process parameters: mean cell residence time
(MCRT), mixed liquor suspended solids (MLSS) and food to microorganism ratio
(F/M). The biomass and its characteristics are controlled by varying these
interrelated process parameters. The following changes to these parameters
have been observed to mitigate the effects of industrial pollutants on an
activated sludge system:
1. Increase the Mean Cell Residence Time. Increasing the MCRT
(sludge age) has been shown to have the effect of reducing the
inhibitory effects of all forms of toxic industrial contaminants. By
increasing the MCRT at the first sign of a possible toxic upset, (by
decreasing the solids wasting rate) the inhibitory effect of any
toxicant will generally be less than if no action is taken.
2. Increase the Mixed Liquor Suspended Solids. High mixed liquor
suspended solids (MLSS) concentrations have been shown to offset
some of the effects of industrial pollutants. A high MLSS provides
the best conditions for biosorption and acclimation to a toxic
substrate. Increasing the sludge return rate to the aeration basin at
the first indication of toxic upset, while at the same time diverting
and storing any remaining toxic influent away from the aeration
basins, will lessen the impact of a short term upset and cause quicker
biomass acclimation to a long term problem.
3. Decrease the Food-to-Microorganism Ratio. This parameter is
directly related to both the MCRT and the MLSS. It has been
observed that decreasing the F/M causes improved biodegradation of
toxic comtaminants, and expedites biomass acclimation.
Table 4.1 summarizes these process control steps.
The process control steps described apply to both activated sludge systems
treating for carbonaceous removal and nitrifying systems. Generally, the steps
described are beneficial for treating any type of interfering pollutant, whether it
be a metal, toxic organic or high-strength conventional pollutant.
For a fixed film process, control of the biomass characteristics is not as easily
accomplished. However, varying the amount and point of recirculation in a
trickling filter can modify the inhibitory effect of industrial pollutants.
Recirculating secondary clarifier effluent is a means of achieving the greatest
dilution effect, which may be desirable for high-strength organic waste or
toxics. Should excessive biomass sloughing be a problem due to toxic pollutants,
returning uncontaminated secondary clarifier underflow may help in maintaining
a proper biomass population.
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4.1.2 Biological Augmentation
Biological augmentation is a method by which selected microorganisms are added
to an existing biological population in an attempt to improve some characteristic
of the biological system. Conclusive evidence is lacking, but biological
augmentation of secondary treatment systems has been reported to improve
some industrial pollutant treatment by promoting the specific microorganism
populations that successfully degrade particular pollutants. Other enhancements
reported include reduced sludge production and increased COD removal rates
(Grubbs, 1986). The addition of selected microorganisms to an aeration basin is
relatively inexpensive and in the worst case will have no effect on treatment.
The EPA, through ongoing experiments at the Wastewater Engineering Research
Laboratory in Cincinnati, Ohio, is presently studying the subject in greater
depth. Maiden Creek, Pennsylvania employed biological augmentation to
improve treatment, however the results of these efforts were clouded due to
other modifications made at the same time (see Appendix A). Rotating
biological contactors plants have used selected bacteria under substrate-limiting
conditions as a control on biomass growth, but with limited success.
After a treatment upset has occurred, biological augmentation by reseeding with
viable microorganisms is a useful step in getting a plant up and running quickly.
Having commercially packaged microorganisms available and in supply at a
treatment facility may help in speeding such a recovery if reseeding from
another treatment facility is difficult.
4.1.3 Chemical Addition
The addition of chemicals or nutrients to the wastewater stream in existing
treatment steps has been shown in many instances to mitigate the effects of
some industrial pollutants. The following are examples of chemicals or additives
that have been shown to improve industrial wastestream treatability or
biological process stability:
chlorine
nutrients
lime or caustic
organic polymers
inorganic coagulants
powdered activated carbon
Table 4-2 lists these chemicals and additives, the reasons for their use and the
resulting effects. The reader is cautioned that the generalizations in the table
do not apply to all situations. Some exceptions are pointed out in the text.
Chlorine. Chlorine has been shown to be successful in controlling bulking
activated sludge caused by industrial pollutants from such industries as textiles,
breweries and wood and paper products. Points of chlorine addition vary, but
best results generally occur when chlorine is added to the aeration basin effluent
or return activated sludge (RAS). The Horse Creek Plant in North Augusta,
South Carolina and the East Side Plant in Oswego, New York are examples of
facilities which have successfully employed chlorination to control bulking sludge
(see Appendix A).
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Nutrients. Phosphorus addition and, to a lesser extent, sulfur and nitrogen
addition, occasionally improve biological treatment and sludge settleability of
industrial wastewater with high carbonaceous content. In general, better
treatment and settleability is attributed to correcting a nutrient deficient
condition resulting from a high industrial/domestic wastewater ratio.
pH Adjustment. Lime and caustic are sometimes successful at mitigating the
effects of some heavy metals on activated sludge systems. Addition of either
before primary treatment has the effect of raising the pH which generally
improves precipitation of heavy metals in primary clarifiers. There are
exceptions to this generalization, however. For example, it makes a difference
whether the pH is being raised from 2 to 6 or from 7 to 11. In this latter case,
iron and chromium will go into solution rather than precipitate. Optimum pH
ranges exist for metal insolubilities, but these ranges are affected by many
factors and are therefore system dependent. Lime can also be used for pH
adjustment of an acidic wastewater prior to aeration to provide a more
conducive environment for biodegradation.
Coagulants. Polymers and inorganic coagulants such as alum and ferric chloride
are introduced to POTW wastestreams in part to help mitigate the effects of
industrial pollutants. Added prior to primary treatment, the coagulants improve
primary sedimentation and may increase the removal of toxic pollutants before
they reach the aeration basins. Added after the aeration basins, the coagulant
aids can assist in controlling bulking sludge and reducing effluent suspended
solids. Jar testing is an important part of any chemical addition program as the
best means of determining optimum dosages. The North Shore Sanitation
District in Gurnee, Illinois has utilized coagulants successfully for mitigating the
effects of interference (see Appendix A). It should be noted that chemical
coagulants affect the characteristics of the sludge and could alter ultimate
disposal methods. If added after secondary treatment, they could increase the
toxicity of the recycle sludge. Therefore, their use should be carefully evaluated
and contamination potential should be investigated.
Activated Carbon. The addition of powdered activated carbon (PAC) to an
activated sludge unit has been successful at reducing the inhibitory effect of
toxic organic chemicals. By providing adsorption sites, the organic pollutants
not biodegraded are removed by the activated carbon. The activated carbon also
improves sludge settleability by providing dense floe nuclei. A patented process
(PACT, licensed and sold by Zimpro, Inc) exists employing this treatment
concept at full scale. However, even a slug additon of PAC to an aeration basin
known to contain toxics can significantly reduce the effects of the toxics on the
biomass.
4.1.4 Operations Modification
Activated Sludge Alternatives. A further means of mitigating the effects of
industrial pollutants on POTWs is through modifying the operation of existing
treatment steps. Activated sludge systems are often designed to operate in
several different "modes" (e.g., step aeration, contact stabilization, etc.) by
providing the appropriate physical layout. Some modes of operation have been
shown to be more successful than others at mitigating the effects of industrial
46
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contaminants, particularly those dosed in highly variable concentrations. It has
been shown at the laboratory and plant-scale that extended aeration and step
aeration (step feed) are generally more resistant to upset than complete mix and
conventional activated sludge (see East Side Plant, Oswego, New York,
Appendix A). It appears that complete mix generally provides more consistent
treatment, particularly under shock loading conditions, than conventional plug
flow treatment. The contact stabilization mode is generally less successful at
treating industrial pollutants than other modes, particularly when the organic
matter is predominantly soluble and waste strength fluctuations are common.
Staged Treatment. A successful means of mitigating the effects of industrial
contaminants on any biological treatment process is through the use of staged
treatment. Many treatment systems have realized improved conventional and
industrial pollutant removal when switching from parallel treatment to series
treatment. For example, two aeration basins operating in series are generally
more successful at mitigating the effects of industrial contaminants than the
same two basins operating in parallel. The same principles have been observed
to apply equally to fixed film processes and fixed film/suspended growth
combinations.
Excess Biomass. A typical response of a fixed film process to some industrial
waste stressing is excess biomass growth, resulting in clogged media and reduced
treatment efficiency. Should this be a problem, treatment is generally improved
if the biomass population (thickness) can be reduced. By increasing or altering
shearing forces, biomass sloughing increases. This can be accomplished by
altering the direction of flow through RBCs and submerged fixed film basins, or
by increasing or altering the aeration pattern (if any) in the basins. A second
means of inducing increased biomass sloughing is through chemical addition, but
this approach is potentially harmful to the biomass and should only be attempted
under the guidance of professionals skilled in the use of such chemicals.
4.1.5 Physical Modification
The most permanent type of industrial pollutant mitigation effort that can be
undertaken at the POTW itself comes in the form of physical addition to or
modification of the treatment system. Successful modification of treatment
plants for industrial waste effects mitigation have included the addition of new
plant facilities such as flow equalization and physical/chemical treatment steps,
the addition of facilities for adding chemicals (as previously discussed) to
existing treatment processes, and the modification of existing biological systems
(i.e. converting to oxygen activated sludge or replacing rock trickling filter
media with plastic media).
Flow Equalization. Adding flow equalization prior to biological treatment units
has the effect of dampening any slug or diurnal loads of noncompatible or
high-strength industrial contaminants entering a treatment plant. Pollutants
that intermittently enter a POTW in inhibitory concentrations can be diluted by
flow equalization to noninhibitory levels and thus, not adversely impact the
biological system. Maiden Creek, Pennsylvania provides a dramatic example of
the effects of non-equalized industrial flows (see Figure A-4). In this particular
case, hydraulic shocks were accompanied by organic shocks that resulted in
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solids carryover, reduced BOD removal efficiency and sometimes total biological
process failure.
Instrumentation/Control. Some POTWs use a variation of the flow equalization
principle with success, especially when toxic metal pollutants are involved. pH
and conductivity of the influent wastewater is measured and recorded con-
tinuously in the influent. When the pH drops or conductivity rises drastically,
possibly indicating an increased heavy metal level, the influent flow is diverted
to a holding basin until such time that the pH and conductivity in the influent
return to normal. At that time, the diverted wastewater can be bled back to the
influent wastestream in a manner such that metal concentrations are diluted and
do not inhibit the biological system. This type of technique may become more
useful in the future as continuously recording specific ion electrodes are
developed for more pollutants.
An example of similar control steps is Chicago Heights, IL. Officials there were
alerted to a pesticide spill that entered the sewer system. Operators were able
to isolate the incoming spill to some parallel primary clarifiers, activated sludge
and aerobic digester tanks where the toxic materials were subsequently treated
chemically and biologically (Busch, 1986). Passaic Valley, New Jersey and
Newark, Ohio employ similar procedures when necessary (see Appendix A).
Special Treatment Operations. Other treatment steps that might be added
depend on the interfering industrial pollutants. The addition of
flotation/skimming tanks is beneficial for removing pollutants like oils, greases
or other water-immiscible compounds. Separate settling basins may be benefi-
cial in some cases for chemical treatment to precipitate metals or cause
coagulation of unsettleable solids.
Pure Oxygen Activated Sludge. Another type of treatment plant modification
that has experienced some mitigation success is the replacement of an existing
air activated sludge unit with oxygen activated sludge. Pure oxygen activated
sludge has been reported by U.S. EPA (1981c) to be a more biologically stable
process with improved sludge settleability over conventional air facilities when
responding to toxic or high-strength organic loadings. However, a disadvantage
with a covered oxygen system is that volatile organics can build up to potentially
explosive levels inside the covers. Baltimore, Maryland and Passaic Valley, New
Jersey have both experienced problems of this type.
Oxygen Transfer. Increasing the efficiency of oxygen transfer in aeration basins
will help mitigate the effects of high-strength conventional pollutants. Retro-
fitting existing coarse bubble or turbine aeration units with fine bubble units may
provide additional treatment capacity for a high-strength waste (see Newark,
Ohio and Maiden Creek, Pennsylvania in Appendix A). However, maintaining
oxygen levels above 2-3 mg/1 has not been shown to consistently result in a
better treatment of conventional or organic pollutants.
4.1.6 Summary
Table 4-3 summarizes the available measures that may be employed at a
treatment plant to mitigate interference effects.
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4.2 PRETREATMENT AND SOURCE CONTROL
Pretreatment and source control of interfering industrial pollutants is the most
direct and efficient way of mitigating the effects of industrial pollutants
because the cause of the interference never reaches the POTW. This reasoning
was the impetus for the General Pretreatment Regulations which specify the
guidelines under which municipalities must develop pretreatment programs. It is
not the intent of this guidance manual to discuss pretreatment guidelines,
complete program development or details of industrial treatment processes.
Rather, this discussion is intended to document elements important to bringing
about pollutant source control, whether as part of a municipal/industrial
cooperative agreement or a fully approved pretreatment program.
4.Z.1 Local Limits
Setting local industrial discharge limits is one of the best and most direct ways
of mitigating any industrial interference that may exist at a POTW. Federal
Categorical Pretreatment Standards must be applied by POTWs with federally-
approved pretreatment programs, but this does not guarantee interference
prevention because of the uniqueness of POTWs and the waste they treat. In
addition, noncategorical industries are not regulated by such federal standards.
Setting rational, technically-based local limits in a fair and equitable manner is a
sound approach to preventing interference. The General Pretreatment
Regulations (40 CFR Part 403.5(c)) require POTWs with federally-required
pretreatment programs and other POTWs which experience pass-through or
interference to establish local limits. Details on the development of local
discharge limits are contained in the "Guidance Manual for POTW Pretreatment
Program Development" (U.S. EPA, 1983). In addition, a computer
program/model for helping municipalities develop local limits has been
developed (U.S. EPA, 1985a) and is available from the EPA Office of Water
Enforcement and Permits.
4.2.2 Accidental Spill Prevention
It is in the best interests of any municipality to consider developing an
accidental spill prevention program (ASPP). The purpose of an ASPP is to
provide "...a set of procedures and a regulatory structure that will minimize the
chance that accidental spills of toxic materials will damage a municipality's
collection system or treatment plant" (U.S. EPA, 1986b). The principal
elements of an effective municipal ASPP are:
identification of potential sources and types of spill materials
adequate regulatory control
POTW review of industrial user spill prevention programs
complete emergency response procedures
documentation of the development strategy
Spill materials would include all sources and types identified for industrial
pretreatment, but would also include apparently insignificant users who have the
potential for spillage into floor drains connected to a POTW. Facilities such as
chemical warehouses, radiator shops, etc., which are supposedly "dry" or usually
recycle all harmful wastes, could have an accident that would impact a POTW.
49
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A POTW should require industrial users to develop their own in-house ASPP and
the program should be reviewed for thoroughness and effectiveness by the
POTW. Industrial user ASPPs, as well as the overall ASPP should include
complete emergency response procedures by all involved parties. These proce-
dures must be outlined in enough detail to be effective and all the appropriate
personnel must be adequately familiar with the necessary emergency steps.
Finally, the development of the ASPP must be well documented so that as time
passes and modifications become necessary, a written record of the program
development will be available for consultation. This record should prevent
needless rethinking of old ideas.
An active spill prevention program with a high degree of visibility can have a
positive impact on reducing unauthorized discharges of industrial wastes.
Figure 4-1 outlines the fundamental procedures in the development of an ASPP.
4.2.3 Pretreatment Facilities
There exists a wide variety of treatment processes applicable to industrial
pretreatment, depending on the wastestream pollutants, the volume of the
wastestream and the extent to which the waste must be treated. The application
of specific treatment streams is not addressed by this document. However,
many typical municipal treatment processes can be applied to some industrial
wastestreams. There are many other types of treatment processes, usually
physical/chemical, applicable to pretreatment applications.
In many cases where industries have been required to pretreat wastes, it has
been found that wastewater flow equalization, pH neutralization or conservation
and recycle/reuse have been all that are necessary to meet discharge limits and
eliminate interferences. Process modifications or wastestream recovery
processes (such as for metals) have in some cases ended up saving industries
money in addition to reducing pollutant loads. These aspects of pretreatment
should be emphasized in discussions with industries. The Horse Creek facility in
North Augusta, South Carolina, experienced significant operational improvement
from relatively small industrial operation changes (see Appendix A).
Modifications such as discharging sump water from the surface rather than the
drain and equalizing pumping schedules, so as to minimize hydraulic peaks were
typical of successful adjustments.
4.2.4 Regulation of Waste Haulers
POTWs that accept discharges of hauled waste should establish procedures to
control the wastes so as to ensure that they are compatible with the treatment
process. A waste hauler permit or "manifest" system is an effective method of
regulation. Use of such a system to document the origin, transportation, and
disposal of the waste, along with a source control program (permitting, sampling
and inspecting the generator) and predischarge sampling, will provide a high
degree of control over incoming wastes. Figure 4-2 presents an overview of the
procedures of a waste hauler permit system.
50
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POTWs may choose to restrict the discharge of hauled waste either to a
designated point in the collection system or to the plant itself. These
restrictions may be implemented through a permit or license. Larger POTWs
that can handle the slug load from a hauler, may grant access to the headworks.
In other cases, where storage or equalization capacity is available, hauled waste
may be discharged to equalization or holding tanks, where it can be charac-
terized prior to introduction to the system. Sioux City, Iowa has developed a
successful method to regulate the impact of waste hauler discharges (see
Appendix A). A large holding receptacle is utilized for all wastes and the
contents are metered to the treatment plant in controlled dosages, so as to
prevent any upsets from high strength waste.
If hauled waste discharges are restricted to a single site, the POTW can easily
inspect and sample the waste, verify tracking records, supervise the discharge of
the waste, and prohibit the discharge of wastes that would be incompatible with
the POTW. Such supervision will also discourage illegal discharges. Monitoring
of a collection system discharge point is more difficult than monitoring a
headworks discharge point. However, dilution of the waste is achieved when
discharged at a remote location in the collection system.
Waste generators may be regulated by permits specifying conditions such as self-
monitoring requirements, local limitations, categorical standards, specific prohi-
bitions, etc., which must be met before allowing discharge. Procedures to
control generators of hauled wastes should be similar to those employed for
generators of fixed discharges, since both are covered by the General Pretreat-
ment Regulations (40 CFR Part 403). The POTW may inspect the generator's
facility and sample the wastes for pollutants of concern to the POTW, as well as
determine if any other wastes have the potential for being mixed with the wastes
that are to be hauled. Based on inspection results, the POTW may sample for
those pollutants which should be limited before discharge is allowed.
If the POTW monitors the waste prior to discharge, one sample of the waste may
be analyzed for a single indicator parameter and a second sample preserved in
case any problems occur after introduction to the POTW. While this might
subject the POTW to unknown pollutants, it would save the cost of analyzing
each load extensively. In the case of manifest discrepancies, or where the
sample failed the indicator parameter test, or where an interference resulted,
more comprehensive testing could occur.
A waste hauler permitting and monitoring program should serve as a deterrent to
haulers against discharging illegal or harmful wastes. If deterrence alone is
unsuccessful, such a program could trigger enforcement action such as fines,
refusal of wastes, permit revocation, or assignment of liability for damages.
4.Z.5 Planning for Future Sources
To prevent the likelihood of future interferences developing, POTW officials
must plan for future sources of industrial pollutants. Future pollutant loadings
should be considered from two sources: new industries, and new pollutant
streams of existing industries. Planning for future sources is particularly
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important as it relates to local limits development. Future pollutant sources and
quantities must be considered in setting local limits, so that a treatment facility
is able to handle increased pollutant loadings adequately.
4.3 LEGAL AND ENFORCEMENT REMEDIES
Interference is costly to POTWs in terms of worker safety, physical plant
integrity, effectiveness of operation, and liability for NPDES permit violations.
Interference is also a violation of a federal prohibition applicable directly to
industrial users. POTWs are required to establish local limits as necessary to
prevent interference and to take appropriate enforcement actions against
violators.
In order to prevent and quickly remedy interference, the POTW must be ready to
exercise its authority to take effective enforcement and legal actions. These
actions should be clearly defined and readily understood by all parties involved.
The range of enforcement mechanisms available to the POTW will depend on the
legal authorities given to it by the municipality, county, and state. Wastewater
treatment personnel who have not had extensive experience with enforcement
and legal proceedings in the past should consult with the POTW's attorney, city
solicitor, or comparable city official to determine what options are available.
POTWs which have federally-approved or state-approved pretreatment programs
should consult their program submission documents regarding legal authority and
enforcement procedures.
EPA has recently distributed a comprehensive guidance document for POTWs
titled Pretreatment Compliance Monitoring and Enforcement (PCME) Guidance
(EPA, 1986c). It provides detailed discussions on compliance monitoring,
establishing enforcement priorities, and conducting enforcement actions. The
PCME guidance should be examined by POTW personnel for the development or
review of their enforcement response procedures. POTWs are encouraged to
develop an enforcement response guide containing procedures which will define,
in a nonsubjective way, the type of enforcement response that can be expected
for a particular kind or level of violation.
Enforcement actions for POTW interference or industrial discharge noncom-
pliance are typically spelled out in the local sewer use ordinance, permits or
contracts with industrial users, or an approved pretreatment program. In
addition, the enforcement procedures can be described in the POTW's enforce-
ment response guide or their NPDES permit. It is important that the enforce-
ment options be strong enough to provide a real deterrent to the regulated
industries. This requires that adequate manpower and documentation exist to
pursue enforcement actions. Documentation will primarily consist of industrial
waste monitoring as discussed elsewhere in this manual. An in-depth evaluation
of all documentation concerning monitoring results, methods, and techniques, as
well as quality assurance procedures should be part of the preparation for
enforcement proceedings.
In interference situations in which there is imminent endangerment to human
health, the environment, or the POTW, it is important that the POTW have the
ability to immediately notify the discharger and bring about a halt to the
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discharge. POTWs with approved pretreatment programs are required to have
this authority by the General Pretreatment Regulations (40 CFR 403.8 (f)(vi)(B)).
In situations in which there is no threat of immediate harm, enforcement steps
usually begin with noncompliance warnings, meetings and other informal actions.
Should these measures prove inadequate, other more stringent measures should
be taken. These commonly include:
penalties
orders and compliance schedules
litigation
sewer disconnection and permit revocation
Bayshore Regional Sewerage Authority (Union Beach, New Jersey) and
METRO-Seattle, Washington are examples of POTWs which have shown aggres-
sive enforcement efforts (see Appendix A). These POTWs have not hesitated to
levy fines and take other enforcement actions after documenting the source of
interference problems.
Both formal and informal actions are important parts of an effective
enforcement program. Informal actions are likely to be more successful if the
POTW has developed a cooperative relationship with its industrial users.
Virginia's Hampton Roads Sanitation District provides a good example of the
advantages of developing and maintaining a good working and monitoring
relationship between an authority and the industrial user community. Once the
interfering source is located, the District technicians, along with a supervisor,
directly contact the industry to notify them of the problem and see to it that the
discharge ceases. The District approaches the source of any interference in a
cooperative manner, with ample documentation in hand. The source is normally
willing to rectify the problems and agreement on administrative and other
measures is reached informally, without the need to resort to legal remedies. If
a clean-up is warranted, the responsible industrial user contracts for the
necessary work to be done, with District personnel overseeing the operation until
completion. All costs involved with the investigation, clean-up and any other
District expenditures as a result of the upset are then billed to the industrial
source.
4.3.1 Penalties
After compliance warnings and efforts to encourage industrial pretreatment
have failed, the enforcement option most commonly initiated is the use of
penalties. The amount of a penalty is generally limited through state or
municipal laws. EPA's "Guidance Manual for POTW Pretreatment Program
Development" (October, 1983) recommended that POTWs have the ability to
assess penalties of at least $300 per day of violation to act as a sufficient
deterrent. However, this limit may be inadequate for discharges which interfere
with the POTW. Appropriate action may involve seeking the assistance of the
state or EPA for obtaining penalties under state or federal law, which may be
substantially greater (up to $100,000 per day and 6 years in jail for a repeat
knowing criminal violation). Penalties may be used in conjunction with billing
procedures for minor violations which may be detected during inspections or
compliance review of self-monitoring data. Such penalties should appear as a
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separate item on a bill with the violation identified. The amount of the penalty
imposed will usually depend upon the nature and severity of the interference
caused or the quantity of the interfering pollutant.
Surcharges are not penalties, but rather recover the POTW's cost of treating
industrial wastewaters. Payment of surcharges is not a justification for an IU to
violate pretreatment standards or cause interference. POTWs should make it
clear to their industrial users, as part of the IU permit or contractual agreement,
that lUs may be subject to both surcharges for the additional treatment costs, as
well as substantial penalties for causing interference.
4.3.Z Orders and Compliance Schedules
In order to force an industrial user to install acceptable pretreatment equipment,
some POTWs may issue administrative orders to place an industrial user on an
enforceable compliance schedule to meet pretreatment standards. Additionally,
orders are sometimes used to require increased monitoring or installation of slug
notification systems.
The Hampton Roads Sanitation District, for example, may modify an industry's
discharge permit to reflect increased monitoring for a period of time to show
compliance. Also, a compliance schedule from the industry is required to show
what steps are taken to prevent recurrence. Depending on the severity of the
problem, the District may require the industry to permanently install some type
of alarm system and/or automatic shut-off.
4.3.3 Litigation
POTW-initiated litigation can be used as a further attempt to cause compliance
after earlier measures have failed to bring about the desired result. In many
cases, litigation is a way of obtaining an injunction against the discharger to
cease the discharge or to clean it up, or to obtain a sewer disconnection or the
payment of substantial penalties which go beyond routine fines. Litigation also
serves to bring media attention and public pressure to bear when pressure from a
sewer authority has failed. For example, the City of Canandaigua, New York
obtained an out-of-court settlement dictating a compliance schedule for a user
following the City's initiation of court action. The user was required to expand
its pretreatment facility and the City's POTW operation was then able to meet
its NPDES permit.
In some cases, litigation has been initiated to collect unpaid fines, which may
amount to sizeable sums. New Jersey's Bayshore Regional Sewerage Authority
found adverse publicity to have little effect on a major industrial employer, and
was forced to initiate legal action hi an attempt to recover $1.25 million in back
surcharge payments and costs.
4.3.4 Sewer Disconnection or Permit Revocation
Sewer disconnection or permit revocation is used by many POTWs under serious
circumstances such as when there is imminent endangerment to public health,
the environment or the POTW, or when other methods to obtain compliance have
failed.
54
-------
A local ordinance can provide this authority by allowing the POTW to issue a
suspension order and by requiring the discharger to immediately halt discharging
upon notification. Furthermore, the ordinance can allow the POTW to sever the
sewer connection if the industry does not respond.
Frequently, unless there is an immediate threat to human health, an administra-
tive hearing of some type is held before discontinuing service. The industrial
user is invited to appear before a local hearing board, presented with the facts
demonstrating noncompliance, and asked to show cause why service should not be
discontinued. The board then decides whether to pursue disconnection.
Recently in New Jersey, the Hamilton Township Wastewater Treatment Plant
required an industrial user to install flow equalization equipment. However,
deterioration in effluent quality continued, leading to termination of sewer
service. In Pennsylvania, the Maiden Creek Wastewater Treatment Plant
discontinued service to a user when the discharge from the facility caused a
total process failure. Any future failure to comply with municipal requirements
for flow equalization and monitoring, BOD reduction, and sampling will subject
the user to another shut-off. The Bayshore, New Jersey Regional Sewerage
Authority's policy is to notify recalcitrant industries of a violation, with
subsequent discontinuation of service if noncompliance extends beyond 15 days.
At Hampton Roads in Virginia, if a problem represents an imminent hazard to
the public health, safety or welfare, or to the local environment or to any
portion of the sewerage system, the District may suspend a permit for a period
of up to 60 days. Failure to immediately cease discharge of all industrial
wastewater into the sewerage system may also result in termination of water
and/or wastewater service. If cooperation is not received from the user, then
the District may revoke the industrial user's permit.
55
-------
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FIGURE 4-2
PROCEDURES OF A WASTE HAULER PERMIT PROGRAM
(U.S. EPA, 1985a)
60
-------
REFERENCES
Busch, W.H. (1986) "Protecting Your Plant From Hazardous Waste." Operations
Forum, WPCF, April Issue. 11-15.
Geating, J. (1981) "Literature Study of the Biodegradability of Chemicals in
Water (Vols. 1 and 2)" U.S. EPA, Cincinnati, Ohio. 241 pp.
Grubbs, R.B. (1986) "Biotechnology Proves Good Examples." Pollution
Engineering, June, 1986.
Russell, L.L., Cain, C.B. and Jenkins, D.I. (1983) "Impact of Priority Pollutants
on Publicly Owned Treatment Works Processes: A Literature Review." Proc.
37th Ind. Waste Conf. Ann Arbor Publishing, Ann Arbor, Michigan. 871-883.
Silva, S.J. (1981) "EPA Moving to Control Industrial Toxic Pollutants with New
NPDES Permits." Civil Engr. 51:76.
Slattery, G.H. (1986) "Patapsco Wastewater Treatment Plant Standard Operating
Procedure: Routine Operation of Wastewater Respirometer", Baltimore,
Maryland.
U.S. EPA (1977a) "Process Control Manual for Aerobic Biological Wastewater
Treatment Facilities." Prepared by Tsugita, R.A., De Coite, D.C.W. and Russell,
L.L. for U.S. EPA, Washington, DC.
U.S. EPA (1977b) "Federal Guidelines - State and Local Pretreatment Programs."
U.S. EPA, Municipal Construction Division MCD-43, EPA-430/9-76-017a,
Washington, D.C. 3 volumes.
U.S. EPA (1978) "Field Manual for Performance Evaluation and Troubleshooting
at Municipal Wastewater Treatment Facilities." EPA-430-9-78-001. Prepared
by Gulp, G.L. and Heim, N.F. for U.S. EPA, Washington, DC. 387 pp.
U.S. EPA (1979) "Biodegradation and Treatability of Specific Pollutants." EPA-
600/9-79-034. Prepared by Barth, E. F., and Bunch, R. L. for U.S. EPA,
Cincinnati, Ohio. 60 pp.
U.S. EPA (1981a) "304(g) Guidance Document: Revised Pretreatment Guidelines
(Vols. I and H)." Internal Report. Prepared by JRB Associates for U.S. EPA,
Cincinnati, Ohio.
U.S. EPA (I981b) "Assessment of the Impacts of Industrial Discharges on Publicly
Owned Treatment Works." Report submitted to the Office of Water
Enforcement, U.S. EPA, Washington, D.C. by JRB Associates.
61
-------
U.S EPA (1981c) "Parallel Evaluation of Air and Oxygen-Activated Sludge."
EPA-600/2-81-155. Prepared by Austin, S., Yunt, F. and Wuerdeman, D., for
U.S. EPA, Cincinnati, Ohio, 43 pp.
U.S. EPA (1983) "Guidance Manual for POTW Pretreatment Program
Development." U.S. EPA, Office of Water Enforcement and Permits,
Washington, DC.
U.S. EPA (1984) "Improving POTW Performance Using the Composite Correction
Program Approach." U.S. EPA, Center for Environmental Research
EPA-625/6-84-008, Cincinnati, Ohio. 258 pp.
U.S. EPA (1985a) "PRELIM: The EPA Computer Program/Model for Developing
Local Limits - User's Guide." Prepared by SAIC/JRB Associates for U.S. EPA,
Office of Water Enforcement and Permits, Washington, DC.
U.S. EPA (1985b) "Pretreatment Implementation Review Task Force: Final
Report to the Administrator." U.S. EPA, Washington, DC. 75 pp.
U.S. EPA (I985c) "RCRA Information on Hazardous Wastes for Publicly Owned
Treatment Works." U.S. EPA, Office of Water Enforcement and Permits,
Washington, D.C.
U.S. EPA (1986a) "Interferences at Publicly Owned Treatment Works (POTWs)."
Submitted to U.S. EPA-WERL, Cincinnati, Ohio by James M. Montgomery,
Consulting Engineers, Inc.
U.S. EPA, Region X (1986b) "Guidance Manual for the Development of an
Accidental Spill Prevention Program." Prepared by Science Applications
International Corp. for U.S. EPA, Region X, Seattle, Washington.
U.S. EPA (1986c) "Pretreatment Compliance Monitoring and Enforcement
Guidance" U.S. EPA, Office of Water Enforcement and Permits, Washington, DC.
WPCF (1982) "Industrial Wastewater Control Program for Municipal Agencies."
MOP OM-4, WPCF, Washington, DC. 166 pp.
62
-------
APPENDIX A
CASE STUDIES
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A-2
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BACK RIVER WASTEWATER TREATMENT PLANT
Baltimore, Maryland
The City of Baltimore owns and operates two wastewater treatment facilities,
Back River and Patapsco, with a combined flow rate of approximately
250 million gallons per day. The plants serve a combined population of nearly
1.7 million in an area which includes approximately 4,700 sources or potential
sources of nondomestic wastewater. In accordance with the requirements of the
General Pretreatment Regulations (40 CFR Part 403) established by the
U.S. EPA, the City developed an extensive industrial waste control program
requiring a significant commitment in terms of personnel, equipment, office
space, and supplies.
The Back River facility is currently undergoing a major renovation to replace the
30 acres of trickling filter rock media with complete-mix activated sludge, along
with significant alteration and expansion of most process units. The renovation
work is in preparation for new NPDES permit limits of 10/10 (BOD and TSS) and
2 mg/1 (NHg), which will require extensive modification of the system for
nitrification and multi-media filtration. Industrial flows to Back River total
approximately 27 mgd, resulting in metals and solvents in the discharge.
The primary source of metals in the system is from the 12 metal plating
operations identified by the industrial waste survey. If too high, the metals
content in the wastewater restricts the ultimate disposal options for the digested
and dewatered sludge. When local limits were calculated based on unrestricted
distribution of the sludge, the limits were occasionally one-fourth of the
electroplating categorical standards. A compost facility now under construction
is expected to process 150 wet tons of the 450 tons produced each day, beginning
in March 1987.
The benefits of pretreatment for metals removal have been demonstrated at
Back River. An incinerator had been discharging 2 tons of fly ash per hour into
the collection system, which was high in metal content and was responsible for
90 percent of the cadmium in the POTW influent. Other wastewater containing
metals were from steel and automobile manufacturing. In each case, industrial
user pretreatment facilities have come on-line during the past year, with a
measureable drop in influent and sludge concentrations. A summary of the
improved metal content of the sludge from 1984 to 1986 is provided on
Table A-2. Based on the current metal content, the composted sludge will be
acceptable for agricultural use.
The second major area of concern at the Back River plant stems from the large,
batch discharges of solvents, petroleum hydrocarbons and other toxic organics.
In 1985, a 2:00 am discharge of ethyl benzene, xylene and toluene resulted in the
evacuation of the largest pump station and other buildings in town. The problem
was traced to a paint and chemicals manufacturer, which has since improved its
in-house solvent recovery system. A similar evacuation resulted from a
4,000 gallon discharge of xylene by a waste hauler, which was traced to a
A-3
-------
specific location in the collection system. Tetrachloroethylene has been
discovered and traced to dry cleaning operations. While such discharges have not
usually resulted in interference with the plant's ability to meet its NPDES permit
limits, the health and safety issues and potential for explosion are of serious
concern to the City.
TABLE A-Z
AVERAGE METAL CONTENT OF
BACK RIVER SLUDGE
(mg/kg dry weight basis)
Metal Allowable1 1984 1986 % Reduction
Cr (total)
Cu
Pb
Ni
Zn
Cd
Hg
NA
I960
730
575
5,130
48
12
1,491
1,001
372
266
2,747
26
5
273
549
388
67
1,522
17
3
82
45
-4
75
45
35
40
From Compost Contract Schedule 2, City of Baltimore, MD
An interesting aspect of Baltimore's program for preventing interference and
sewer system hazards is the computer coding of the sewer collection system. By
knowing the constituents of each industry's discharge, the flow rate and their
location in the coded sewer system, a contaminant discovered at either Back
River or Patapsco can theoretically be traced back to its potential source or
sources. While such a backtracking program is of limited use for isolated
discharges, it could prove beneficial in locating chronic dischargers of specific
compounds.
In order to further protect the sewer system, a City Ordinance requires that the
atmosphere in a manhole receiving an industrial discharge must not exceed 10%
of the LEL (lower explosive limit) for any fuel. This regulation is in force by
manual monitoring of the sewer manhole and has been successful in curbing
intentional dumps or disposal of fuels and flammable solids.
A-4
-------
BACK RIVER WASTEWATER TREATMENT PLANT
BALTIMORE, MARYLAND
Design Flow:
Secondary Treatment:
180 mgd
Trickling Filters and Activated Sludge
INFLUENT WASTEWATER
SIGNIFICANT INDUSTRIES
Ave. Flow, mgd
% Industrial
BOD5, rog/1
SS, rag/1
Typical (Upset)
180 (Z70)
15
130
190
Industry
Metal Plating (12)
Auto Mfr.
Paint and Chemical
Incinerator
Waste Haulers
Flowrate
(mgd)
0.18
1.5
N/A
N/A
N/A
Problem Pollutants
Metals
Cr, Cu, Ni, Zn
Ethyl benzene, toluene, xylene
Cd, Hg
Solvents, petroleum hydrocarbons
PLANT LOADING
Primary Clarifiers
Overflow Rate, gal/s£/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, mg/1
Secondary Clarifiers (A.S./T.F)
Overflow Rate, gal/sf/day
Detention Time, hours
SVI, ml/gm
Typical (Upset)
730 (1,170)
3.6
180
100
Typical (Upset)
750/950
2.5/2.1
95
Aeration Basins Typical (Upset)
Ave. Flow, mgd 60
F/M, Ibs BOD5/lbs MLSS/day 0.4
MCRT, days 6.1
MLSS, mg/1 2,000
Detention Time, hours 3.5
Return Flow, To 30-40
D.O. Level, mg/1 Z-3
Trickling Filters Typical (Upset)
Ave. Flow, mgd 150(200)
Hydraulic Loadings, ga/sf/d 120 (136)
Organic Loading, Ibs BOD/1000 cf/d 20
Return Flow, % 0
, mg/1
SS, mg/1
PLANT PERFORMANCE
Permit Limit
45
45
Typical (Upset)
40 (50)
40 (50)
BAW WASTEWATER
BETHLEHEM STEEL
COOLING WATER
FINAL EFFLUENT
A-5
-------
PATAPSCO WASTEWATER TREATMENT PLANT
Baltimore, Maryland
A 1981 EPA-sponsored project on biomonitoring of direct discharges rated the
Patapsco plant as having the most toxic effluent of those surveyed. Ironically,
the second most toxic discharge came from an agricultural chemicals manufac-
turer who, in 1983, ceased direct discharging and now sends their pretreated
wastewater to Patapsco. The high level of toxicity has prompted the collection
of much bioassay, acute toxicity and respirometer data over the past four years
in order to evaluate the potential for both toxicity pass-through and toxic
inhibition of the plant biomass. Despite the presence of inhibitory levels of
pollutants in the influent, the plant currently meets its discharge limits for BOD
and SS, indicating the ability of activated sludge to acclimate to consistent
levels of many inhibitory compounds. It has, however, been necessary to operate
at a reduced organic loading in order to offset the effects of the inhibition. This
has reduced the wastewater treatment capacity of the plant.
The City is evaluating several measures to reduce this inhibition and thus
prevent any possibility of interference. They have begun daily routine operation
of a respirometer for measuring the inhibitory characteristics of the plant
influent. They are also evaluating the use of respirometry as a tool for assessing
the impacts of several industrial effluents on the plant.
Another concern to the City is the pass-through of toxicity. Acute influent and
effluent toxicity data using a Beckman Microtox unit have been collected since
November 1980. Some of the results of these analyses are shown on Figure A-l.
The data are on an inverse scale, with 0% indicating complete toxicity and
approximately 45 percent corresponding to no toxic effect.
Figure A-l illustrates the highly toxic nature of the plant influent and effluent
until September 1982, at which time the secondary treatment system went on-
line. The acclimation of the activated sludge improved the monthly average
effluent toxicity from 5 percent to 40 percent by December, where it remained
until secondary shutdown in February 1983. The average effluent toxicity again
increased until the secondaries returned on June 15, providing clear evidence of
the detoxification capability of acclimated activated sludge. Even though
overall effluent toxicity has been reduced, individual daily tests continue to show
substantial day-to-day variability, with significant effluent toxicity occurring in
more than one-third of the tests. Therefore, the City is continuing to study ways
to reduce this toxicity pass-through. In fact, the City of Baltimore is currently
performing a toxicity reduction evaluation (TRE) in conjunction with the U.S.
EPA.
As a means of improving both the inhibition and toxicity pass-through situations,
the State of Maryland included the following in a consent order issued to the
City in 1984:
install on-line toxicity monitoring of the plant influent
develop a toxics emergency response plan
enlarge the scope of the City sewer ordinance to include specifics on
toxicity and flammability for industrial effluents.
A-6
-------
u
FIGURE A-l
MONTHLY ACUTE TOXICITY
(Courtesy G.H. Slattery, City of Baltimore)
In spite of high influent toxicity, the plant is not currently experiencing
interference with its ability to meet its NPDES permit limits. With a mean cell
residence time varying between 10 and 15 days, the plant produces reasonably
stable operation and good plant performance on removals of conventional
pollutants. Although compliance with the NPDES permit has been achieved for
BOD and SS at Patapsco, the plant flow is well below the 70 mgd design
capacity. Toxic inhibition of the activated sludge bacteria is still present
despite the improvement since 1983. Evidence of this inhibition is provided by
the plant actual operating F/M of 0.3, which is significantly less than the design
value of 0.5, and also was verified by respirometry tests on the plant influent.
The attached data sheet indicates that Patapsco's current noncompliance has
resulted from discharging excess phosphorus and an effluent pH below 6.5. The
phosphorus problem is being dealt with by installing anaerobic/oxic (A/O)
technology in the oxygenation basins as a means of biological phosphorus
removal. The low pH is inherent in oxygen activated sludge systems, typically
producing an effluent in excess of 250 mg/1 of CO2 and a pH of 6.2. The problem
can be corrected with either chemical adjustment or post-aeration of the
wastewater.
A-7
-------
PATAPSCO WASTEWATER TREATMENT PLANT
BALTIMORE, MARYLAND
Design Flow:
Secondary Treatment:
70 mgd
Activated Sludge (Pure Oxygen)
INFLUENT WASTEWATER SIGNIFICANT INDUSTRIES
Ave. Flow, mgd
% Industrial
BOD5, mg/1
SS, mg/1
TOX, %
Flowrate
Typical (Upset) Industry (mgd) Problem Pollutants
42 Chemicals 1.0 Insecticides, Volatiles, phenols, metals
30
265 (320) Metal Finishing 0.13 pH, solvents, metals
325 (470)
15
PLANT LOADING
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BOD5, mg/1
Effluent SS, mg/1
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
SVT, ml/gm
Typical (Upset)
1,150
1.5
190
30
Typical (Upset)
450
6.3
50-75
Aeration Rising
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Return Flow, %
D.O. Level, mg/1
Typical (Upset)
0.3
10-15
5,000
2
30
2-4
PLANT PERFORMANCE
Permit Limit
Typical (Upset)
BOD5, mg/1
SS, mg/1
Total-P, mg/1
pH
TOX, %
30
30
2.0
6.5-8.5
13 (40)
15 (40)
3.5
6-6.5
40
RAW WASTEWATER
RAS
FINAL EFFLUENT
BAR SCREENS
PRIMARY
CLARIFIERS
(3)
1
1
j
1
1
i
OXYQENATION
BASINS
(4)
/I
AIR
FLOTATION
THICKENERS
(4)
SLUDGE
LENDING
TANKS
(2)
ASH TO
LAGOON
A-8
-------
BAYSHORE REGIONAL SEWERAGE AUTHORITY
Union Beach, New Jersey
The Bayshore Regional Sewerage Authority (BRSA) operates an activated sludge
treatment facility whose performance is largely dictated by a single industrial
waste discharger. Three manufacturers of flavors and fragrances (one of whom
is a perfume retailer) represent the total industrial wastewater flow of
325,000 gpd, or less than 5 percent of the POTW total. All three industries
discharge high concentrations of conventional pollutants and routinely violate
the maximum allowable monthly concentration limits for BOD (500), COD (1500)
and TSS (500) as specified in their industrial waste permits. Two of the three
manufacturers contribute less than 0.5 percent of the POTW flow, hence their
impact is minimal. However, one building of the largest industry produces in
excess of Z00,000 gpd of wastewater with the following characteristics (in mg/l):
1984 October 1985
Monthly Monthly Daily Daily
Parameter Ave. High Low Ave. High Low
BOD 1004 2054 245 2624 5250 522
COD 3238 4998 1440 7084 11380 2520
TSS 776 1835 94 1113 1698 672
The large variation in wastewater quality indicates that a two-stage primary
pretreatment system located at the industry is not sufficient to meet the
fluctuating demands of their process wastes.
The potential impact of such an industrial discharge is evident when analyzing
Figure A-2. The bar graph represents the percentage of total BOD being
contributed by the industry on a daily basis. The upper plot on the line graph
corresponds to the mass BOD loading, with the industry's contribution plotted
beneath. This graph clearly demonstrates that the effluent from this single
industry has increased the BRSA plant loading above the design limit of
15,000 pounds of BOD per day. This has interfered with the plant's ability to
meet its permit limit for BOD.
The BRSA has been particularly aggressive in their dealings with the industry in
question. It has taken a two-pronged approach:
notification of violation with a subsequent discontinuation of service
if noncompliance persists after 15 days, and
legal action to recover $1.25 million in back surcharge payments and
costs.
A-9
-------
00 COWMIMOII
II 1011 2211 24 H« 17 21 It 3031
OCTOIOI 1*M
IMMWTMY MO * % OF TOTAL tOO
Iff Mil 2223 24 2S M tr ti *» 30
OCTOm 1MI
Figure A-2
Impact of Industrial Waste Discharge on POTW Loadings
October 1985
In addition to the BRSA actions, the County Prosecutor's office made a surprise
visit to the industry in question, in which records were confiscated and samples
collected for analysis. The result was a $5 million fine levied by the State of
New Jersey in June of 1986, coupled with new NJPDES permit POTW limits. As
a direct consequence of the state and local acions, the industry's wastewater
BOD and SS have each been consistently below 100 mg/1 since July, 1986. To
date, $300,000 of the back payments have been received by the BRSA, with some
litigation still pending.
A-10
-------
BAYSHORE REGIONAL SEWERAGE AUTHORITY
Union Beach, New Jersey
Design Flow:
Secondary Treatment:
8.0
Activated Sludge
(Modified Contact Stabilization)
Location:
Population Served:
Eastern shore
80,000
INFLUENT WASTEWATER
Ave. Flow, ragd
% Industrial
BODj, mg/1
SS, mg/1
Typical (Upset)
6.6
5
220 (380)
250 (400)
Industry
Flavors & Fragrances
(3 industries)
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd)
325
Problem Pollutants
BOD, TSS, COD
PLANT LOADING
Primary Clariflen
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, mg/1
Secondary Clarifier*
Overflow Rate, gal/sf/day
Detention Time, hours
SVI, ml/gm
Typical (Upset)
SIS
1.75
150 (250)
100 (200)
Typical (Upset)
540
3.35
US (500)
Aeration Basins
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Return Flow, fa
Detention Time, hours
Contact
Reaeration
Typical (Upset)
0.65 (1.25)
8-10
2000-2500
25
3
12
BOD5, mg/1
SS, mg/1
D.O. rog/1
PLANT PERFORMANCE
Permit Limit
30
30
5
Typical (Upset)
35 (400)
27 ISO)
2-5
RAW
WASTEWATER
HAS
PRIMARY
CLARIFIERS (4)
CYCLONE 7*S
1
BASINS
(4)
WAS
ASH TO
SLUDGE LAGOON
INCINERATOR
A-H
-------
EAST SIDE SEWAGE TREATMENT PLANT
Oswego, New York
The City of Oswego, East Side Treatment Plant has experienced significant non-
compliance problems associated with the loss of solids from their secondary
clarifiers. Half of the plant's hydraulic flow is from a paper mill which is the
only major industry in the city. From 1981 to 1983, the noncompliance problems
at the plant were attributed to severe hydraulic and organic load peaks from the
paper mill as well as operational difficulties such as frequent breakdowns of the
return sludge pump drives. It is not known whether filamentous growth in the
sludge occurred at that time. In 1983 the paper mill began reducing the
hydraulic and organic peaks to the plant. Solids losses from the secondary
clarifier still remained a problem. During 1984, the plant frequently exceeded
their NPDES discharge suspended solids by five times the limit and the BOD by
three times the limit. During that period, the plant still occasionally received
hydraulic peaks from the paper mill which were twice the average rate for two
to three hour periods, but a substantial cause of the problem was identified as
poor sludge settleability due to filamentous growth. The frequent washout of
biosolids from the secondary clarifiers resulted in a low mean cell residence
time and the generation of a young sludge that did not settle well. In the spring
of 1985, the belt drives on the return sludge pumps which had frequently been
out of service were replaced with electronic variable speed drives. This
improvement allowed the plant operators to maintain better control of the solids
inventory in the aeration tanks. Plant performance was still poor, however,
because of sludge bulking.
Several measures have been taken at the plant in an attempt to alleviate the
sludge bulking problem. The measures that were taken include:
switching from plug flow feed to a step feed in the aeration tanks in
order to achieve better dissolved oxygen distribution;
increasing the sludge return rate and mean cell residence time to
improve settleability; and
chlorination of the return sludge for the destruction of filamentous
growth in the sludge.
The step feed operation has resulted in better dissolved oxygen distribution but
did not significantly improve sludge settleability. The second two mitigation
efforts were ongoing at the time of writing. A chlorination dosage of
6 Ib C12/1000 Ib solids had been applied to the return sludge. Microscopic
examination of the sludge indicated that the filaments had shrunk and the SVI
level had dropped to the range of 60-80. The plant operators intend to chlorinate
whenever the SVI increases to 150. It has not been determined if these
mitigation measures can result in plant performance that will consistently meet
the permit discharge limits.
The paper mill periodically discharges slugs of waste containing high suspended
solids to the treatment plant. At these times, the sludge in the primary tanks
A-12
-------
takes on a gelatinous quality which makes sludge removal difficult. High
periodic input of clay filler materials from the paper mill has resulted in poor
sludge incineration with associated high fuel usage.
The City of Oswego is presently preparing an industrial discharge permit for the
paper mill. The permit will restrict the monthly and daily average BOD and
suspended solids levels in the influent from the paper mill as well as restrict the
daily maximum hydraulic peak allowed. Under the permit provisions the paper
mill will be required to submit listings of the chemicals used in their processes.
The paper mill is presently investigating the possible relationship of the
chemicals used in their manufacturing processes to the occurrence of
filamentous growth in the activated sludge process.
A-13
-------
EAST SIDE SEWAGE TREATMENT PLANT
OSWEGO, NEW YORK
Design Flow: 3 mgd
Secondary Treatment: Phig or Step Feed
Activated Sludge
Location:
Population Served:
Northern New York
10,000
INFLUENT WASTEWATER
Ave. Flow, mgd
% Industrial
BOD5, mg/1
SS, mg/1
Typical (Upset)
Z.5
50
Municipal Paper Mill
100
120
300
450 (1000)
Industry
Paper Mill
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd)
1,200
Problem Pollutants
SS, BOD
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BOD5) mg/1
Effluent SS, mg/1
PLANT LOADING
Typical (Upset) Aeration Basins
600
Z
Municipal Paper Mill
70
40
120
100
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Return Flow, %
D.O. Level, mg/1
Typical (Upset)
O.Z
7(3)
Z.OOO (300)
1
25 - 45
Z - 4
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
SVI, ml/gm
Typical (Upset)
800
Z
100 (1000)
PLANT PERFORMANCE
Permit Limit
Remainder of
Summer Year
Typical (Upset)
BODs, mg/1
SS, mg/1
30 45
30 70
RAW DOMESTIC RAW PAPER MILL
WASTEWATER WASTEWATER
-L- JL
iSAR
CREENI
^ 4T
JORIT J|
CHAMBERS
L
r~
\ *
1 *-
1 s~ -v
1 /ORAVITY\
L (JTMCKENERBl
*^;
...- f^^nn^i n
J PRIMARY | f H T T T
dcL«RIF,ER8(2)h T 1.LL1 '
U BASINS _*.
1 .k . ,^.
t PRIMARY 11 | "'
CLARIFIERS ttf 1 ^~
WAS
VACUUM <^3
»-|f"-IERS) * ~>
\ (?) y <-~^ ». **
^_^ -. ~~ LAND
I MULTIPLE HEARTH
INCINERATORS (2)
20 (120)
25 (300)
FINAL
EFFLUENT
t
CHLORINE
CONTACT
CHAMBER
t
SECONDARY 1
CLARIFIERS '
<&l
1 I
J
TO
FILL
A-14
-------
HAMILTON TOWNSHIP WASTEWATER TREATMENT PLANT
Trenton, New Jersey
The Hamilton Township Wastewater Treatment Plant (HTWTP) is an unusual
facility in that plant upgrades over the past 30 years have been constructed as
parallel flow processes rather than as replacements for older, outdated techno-
logy. Although this results in a complicated plant schematic (see below), parallel
flow paths do provide operational flexibility and an opportunity to study the
impact of a combined industrial/domestic wastewater on different fixed-film
biological treatment processes. The HTWTP has had a difficult time meeting its
permit limit for BOD over the past few years, and is currently under a Consent
Order and Agreement and Compliance Schedule from the State Department of
Environmental Protection.
Despite being at just over 50 percent of the plant's hydraulic capacity, Hamilton
Township has experienced organic overloads, resulting in at least partial failure
of 15 of the 48 RBC units. With the advent of an Industrial Waste Monitoring
Program as part of a Sewers and Sewage Disposal Ordinance, the reasons for
such overloading became apparent. Although the industrial waste program is
still in its infancy, observations and analytical data have identified a pharma-
ceuticals manufacturer as a significant and potentially harmful discharger to the
POTW.
Dating back to the summer of 1984, high concentrations of volatile organics
were being discharged to the POTW on a once or twice-per-week basis. A
monitoring program at the HTWTP uncovered an increase in influent BOD from
150 to 350-500 mg/1 and high atmospheric levels of organic constituents with
this discharge pattern. The specific industry was identified when a high influent
pH reading led Hamilton Township personnel to the pharmaceuticals manu-
facturer in March, 1985. Sampling conducted at that time detected significant
levels of ethyl benzene, toluene and xylene in the industry's effluent. These
findings precipitated an extensive testing program by the Township, with an
independent engineering study conducted by the industry. The results indicated a
correlation between the pharmaceutical discharges and high influent soluble BOD
at the POTW. Analyses conducted on the industry's flow streams resulted in the
following calculated average effluent concentrations:
Parameter
Arsenic
Phenols
Total Toxic Volatile Organics (TTVO)
BOD
TSS
TDS
Concentration (mg/1)
2.6
25.7
1.3
21,800
557
65,800
Based on an average flow of 15,000 gpd, these wastewater characteristics should
not be harmful to an 8.5 mgd facility if discharged on a steady basis. It is the
intermittent discharge of this wastewater which has contributed to the over-
loading of the biological population of the POTW.
A-15
-------
During a three week shutdown of the industry in July of 1985, the HTWTP
recovered to the point of meeting their permit limits. Consequently, the
Township only permitted the industry access to the sewer system after the
installation of metering pumps to equalize flows. This requirement initially
improved POTW performance during the fall of 1985, but a gradual deterioration
in effluent quality (indicating possible toxicity effects) lead the Township to
terminate service to the industry in late-November.
While the most recent action is being challenged, the industry is constructing an
anaerobic pretreatment facility on site to reduce its loading to the POTW.
A number of operations and personnel changes have been instituted at the
HTWTP to help mitigate the impact of the industrial discharges. These changes
include:
installation of aeration equipment in the influent channels to the
RBCs to increase the first stage DO to 2-3 mg/1;
extensive use of sludge depth measurement and visual monitoring to
augment reliance on control room instrumentation;
performance of bioassay testing by an independent contractor to
assess toxicity effects;
purchase of a toxicity tester to be used in calculation of local limits;
and
hiring of four more people plus the purchase of a vehicle for an
extensive industrial sampling program.
A-16
-------
HAMILTON TOWNSHIP WASTEWATER TREATMENT PLANT
Trenton, New Jersey
Design Flow:
Secondary Treatment:
16 mgd
Trickling Filter and RBC
Location:
Population Served:
Central Western Border
87,000
INFLUENT WASTEWATER
SIGNIFICANT INDUSTRIES
Ave. Flow, mgd
% Industrial
BODs, mg/1
SS, mg/1
Typical (Upset)
8.5
10 (estl
240 (500)
160 (400)
Industry
Pharmaceutical
Electroplaters (2)
Flowrate
(1000 gpd)
15
160
Problem Pollutants
BOD, phenol, ethyl benzene, toluene, xylene
Cd, Cr, Zn, Ni
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
PLANT LOADING
Typical (Upset) Trickling Filters
830, 260, 320
1.8, 4.8, 5.6
Plant Flow (mgd)
Hydraulic Loading, gal/sf/day
Organic Loading, !')s 3OD/1,000 cf/day
Return Flow, %
Typical (Upset)
2.5, 1.0
100, 210
15, 16 (30)
20,100
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Typical (Upset)
520, 260, 265
2.8, 4.S, 6.8
RBCs
Plant Flow (ragd)
First Stage Organic
Loading, Ibs BOD/1,000 sf/day
- Total
- Soluble
Typical (Upset)
5.0
5.3 (10.8)
3.5 (6.7)
PLANT PERFORMANCE
Permit Limit
s, mg/1
SS, rag/1
NHs, mg/1 (Effective 6/86)
30
30
10
Typical (Upset)
45 (100
20 (50)
20 i'30)
RAW
WASTEWATER
TD. RAT
TRICKLING
FILTERS
(3)
SECONDARY
-O-JCLARIFIERS
V~^\
/ VACUUM \
-»4 FILTER J
> 4
» LANDFILL
A-17
-------
HORSE CREEK POLLUTION CONTROL FACILITY
North Augusta, South Carolina
The Horse Creek Pollution Control Facility (HCPCF) is a regional plant,
operated by the Aiken County Public Service Authority (ACPSA), treating a
predominantly industrial wastewater. Ninety five percent of the industrial
wasteload is contributed by several large textile mills and is characterized by
high COD, BOD, alkalinity and pH. Combined domestic/industrial influent
wastewater pH and alkalinity fluctuations caused inhibition of the biomass,
poorly settling sludge and effluent suspended solids permit violations. Since
implementing a pretreatment program and issuing industrial wastewater
discharge permits, the treatability of the industrial waste has improved, the
result being that HCPCF has been free of NPDES permit violations for over
eight months.
Local textile processes include grading operations, finishing processes utilizing
dyes, and specialized textile chemical manufacturing. The textile wastewater is
highly caustic with alkalinity as high as 2400 mg/1, and pH exceeding 12.5. Prior
to pretreatment the combined industrial/domestic influent to the HCPCF had
the following characteristics:
pH
BOD 360 mg/1
COD 910 mg/1
Alkalinity 1100 mg/1
TSS 210 mg/1
Other distinguishing characteristics of the influent wastewater included the
light, non flocculant nature of the suspended solids and a dark blue/black color,
typical of textile wastewater from washing and dying operations.
Prior to the summer of 1985, the textile industries employed a limited type of
pretreatment and flow equalization. This limited pretreatment and flow
equalization resulted in plant influent pH fluctuations of 2 to 2.5 units and
alkalinity fluctuations of up to 600 mg/1 in a given day. These fluctuations
caused some inhibition of the biomass, but because the hydraulic detention time
in the aeration basins was in excess of 3.5 days, effluent BOD was within the
permit limit of 33 mg/1. These pH and alkalinity fluctuations had their most
detrimental effect on biomass settling characteristics and solids carryover in the
secondary clarifier often resulted, lasting for 24-36 hours. During these
episodes, filamentous organisms were occasionally observed in the biomass. The
solids carryover problem worsened in the winter months when wastewater
temperatures were lower, but chlorination of the return activated sludge, the
influent to the secondary clarifier and the contents of the aeration basin was
somewhat successful at improving settleability. Despite this, the HCPCF still
experienced interference with its ability to meet suspended solids limits in 15 of
the 19 months prior to September, 1985.
The State of South Carolina mandated that the ACPSA implement and enforce a
pretreatment program in the spring of 1984. The ACPSA responded by
A-18
-------
developing such a program and issuing draft industrial wastewater discharge
permits. Final State approval came in May, 1985. As presently written, the
industrial wastewater discharge permits are not restrictive, allowing BOD, COD
and alkalinity levels as high as 600 mg/1, 1300 mg/1 and 1500 mg/1, respectively.
However, the permits have caused the textile industries to make small, but
meaningful alterations to their wastewater discharge practices, resulting in
average plant influent pH levels dropping from 11-12 to 10 and alkalinity from
1100 mg/1 to 700 mg/1. More importantly, maximum daily influent pH
fluctuations have been reduced to 0.5 units or less. Figure A-3 shows the
magnitude of pH fluctuations both before and after the implementation of
pretreatment. Simple modifications at textile facilities to process operations
and waste pumping schedules were typical of the changes that were necessary to
realize the described results. Because of the more stable wastewater discharge,
the HCPCF has realized more consistent plant operation and has not violated its
NPDES permit in over eight months.
Some of the textile dischargers do not currently meet the pH and alkalinity
limits of their industrial wastewater discharge permits and are under a
compliance schedule to do so. The facilities are installing pretreatment works
for caustic recovery that should significantly lower pH and alkalinity levels. The
HCPCF is also presently studying the addition of floating mixing units to
augment the turbine surface aerators in the aeration basins. To date, evidence
indicates that a more consistent secondary clarifier solids feed is achieved which
improves the quality of the secondary effluent.
FIGURE A-3
HORSE CREEK POLLUTION CONTROL FACILITY INFLUENT pH
A-19
-------
HORSE CREEK POLLUTION CONTROL FACILITY
Alken County, South Carolina
Design Flow:
Secondary Treatment:
ZOmgd
Extended Aeration
Activated Sludge
Location:
Population Served:
West-central South Carolina
70,000
INFLUENT WASTEWATER
SIGNIFICANT INDUSTRIES
Ave. Flow, mgd
% Industrial
BOD;, mg/1
SS, mg/1
COD, mg/1
Alkalinity, mg/1
pH
Typical (Upset)
10.4
80
360
Z10
910
1100 (1600)
10-11 (12.5)
Industry
Textile
Textile chemicals
Flowrate
(1000 gpd)
8,400
300
Problem Pollutants
COD, Alkalinity, pH
COD, pH
Primary Clarifien
Overflow Rate, gal/sf/day
Detention Time, hours
Secondary Clarifiera
Overflow Rate, gal/sf/day
Detention Time, hours
PLANT LOADING
Typical (Upset) Aeration Basins
300
4.4
Typical (Upset)
195
9.1
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Return Flow, %
D.O. Level, mg/1
Typical (Upset)
0.05-0.10
50-90
3800-4500
9Z
40-60
1-3 (4)
PLANT PERFORMANCE
Permit Limit
Typical (Upset)
BODs, mg/1
SS, mg/1
COD, mg/1
PH
33
57
9
15
40 (85)
175
9 (10)
RAW
WASTEWATER D»Q
r7
\ /
\A *-
SCREENS AND
AERATED GRIT
CHAMBERS (2)
FINAL
EFFLUENT
LANDRLL
V^ \^J
A-ZO
-------
MAIDEN CREEK WASTEWATER TREATMENT PLANT
Blandon, Pennsylvania
The Maiden Creek Wastewater Treatment Plant (MCWTP) went on-line in
December, 1981 as a secondary treatment facility designed to remove both
carbonaceous and nitrogenous BOD. The plant uses a patented aerated sub-
merged fixed film biological treatment system, where flat asbestos plates
hanging vertically in the settled wastewater provide a growth surface for the
bacteria. Each of three contact basins contains 320 plates with 200 sq. ft. of
surface area. Oxygen is provided by fine bubble aeration through ceramic
diffusers.
During the first six months of operation following an initial acclimation period,
the MCWTP experienced gradual flow increases from 0.1 to 0.15 mgd while
consistently meeting their permit limits. In August of 1981, a local mushroom
processor began batch discharging high BOD wastewater to the POTW at flows
sometimes exceeding 100 gpm. The hydraulic and organic shock loadings
resulted in nitrifier washouts, solids carryover, reduced BOD removal efficiency
and at times total biological process failure. Although the industry was not
measuring their wastewater flow rates at that time, they were the only
significant non-domestic contributor. After factoring out any potential infiltra-
tion/inflow from stormwater flows, the discharge pattern from the industry was
obvious from an inspection of the weekly flow recordings at the POTW.
Figure A-4 illustrates the dramatic effect of the industrial discharges on the
MCWTP influent.
April, 1982
October, 1982
FIGURE A-4
WASTEWATER DISCHARGE AT INFLUENT METERING STATION (MGD)
A-21
-------
As a result of significant time and effort on the part of Maiden Creek Township
Municipal Authority two years ago, the food processor installed a physical-
chemical treatment system which included surge control tanks and aeration. The
system did reduce the solids load and partially mitigated the flow spike problem,
although the surge tanks were not capable of providing complete equalization.
Unfortunately, the great percentage of their organic waste is soluble, so the
pretreatment facility is ineffective in reducing the BOD loading to the POTW.
Additionally, wastewater production far exceeds the 50,000 gpd limit imposed by
their permit, so occasional flow spikes are still evident. The industry has
requested nearly ten times the current flow limit, necessitating the design of a
full secondary system to reduce their waste strength to domestic levels. Such a
system, including a 650,000 gallon aerated equalization basin, is scheduled to go
on-line in mid-1986. In the interim, the municipality has required that the
industry:
control flow surges;
meter and record their flows continuously;
reduce the BOD in the effluent by in-house methods; and
composite sample their discharge on a regular basis.
Failure to comply with the abovementioned program will result in a shut off by
the POTW, a measure used previously in February, 1985 when the industry's
wastewater was responsible for total process failure at the plant.
A number of operational changes were instituted in May of 1985 to help combat
the high organic loads in the contact basins. These changes included:
increasing the aeration by using all blowers at the plant, resulting in
an increase in the first stage D.O. from 2 xng/1 to 5 tng/1;
addition of selective strains of bacteria to increase the rate of BOD
removal;
recycling the plant effluent to the head of the plant to dilute the
incoming wastewater; and
reducing the allowable flow from the food processor and closely
monitoring their adherence to the limits.
Since these changes were implemented concurrently, it is impossible to isolate
the individual impacts of each operations change. However, the collective result
was a substantially improved compliance record. There have also been no flow
spikes at the POTW since mid-December, 1985, indicating better flow control on
the part of the food processor.
A-22
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MAIDEN CREEK WASTE* ATER TREATMENT PLANT
BLANDON, PENNSYLVANIA
Design Flow:
Secondary Treatment:
0.45 mgd
Aerated Submerged Fixed
Film (Contact Aeration)
Location:
Population Served:
Southeastern Pennsylvania
Z,000
INFLUENT WASTEWATER
Typical (Upset)
Ave. Flow, mgd
% Industrial
BODs, mg/1
SS, mg/1
NH3, mg/1
0.25
20 (60)
350 (900)
200
60
Industry
Food Processor
Dental Office
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd)
50
negl.
Problem Pollutants
BOD, Flow surges
Hg
PLANT LOADING
Primary Clarifien
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BOD;, mg/1
Effluent SS, mg/1
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Typical (Upset)
350 (1,000)
3.75 (1.Z5)
260
100
Typical (Upset)
450 (1,300)
2.8 (1.0)
Contact Basins
Typical (Upset)
Organic Loading (Ibs BOD5/1000 sf/day)
Total Plant 2.8
First Stage 8.4
Detention Time, hours 12
D.O. Level, mg/1 5-10
BOD;
SS, mg/1
NH3, mg/I
PLANT PERFORMANCE
Permit Limit
30
30
10/20
Typical (Upset)
15 (400)
10 (50)
1 (60)
RAW
WASTEWATEM
I
COMMMUTOR
T
PfNMAJIV
CLAMFKM
1M »TAQE
CONTACT
AERATION
BASIN
1
DM3E8TER
LAND APPLICATION
OR
8LUDQE DRYING BEDS
A-Z3
-------
METRO-WEST POINT TREATMENT PLANT
Seattle, Washington
The Municipality of Metropolitan Seattle (METRO) has had an operational
industrial pretreatment program since 1969- With minor modifications, the
program was EPA-approved in 1981 as one of the first in the nation. Successful
reductions in influent wastewater and primary sludge heavy metal concentrations
during the last five years can, to a great extent, be attributed to implementation
and enforcement of pretreatment standards. As an outcome of this, self-
monitoring by industrial dischargers augmented with year-round spot monitoring
by Metro's Industrial Waste Section has reduced the incidences of toxic upsets in
the anaerobic digesters of the West Point Treatment Plant.
The Metro-West Point Treatment Plant provides primary treatment and sludge
digestion for an average daily wastewater flow of 132 mgd, 4.7 percent origi-
nating from industrial sources. Approximately 70 metal finishing/electroplating
industries discharge to the sewer system in addition to a variety of other
categorical and non-categorical industries. Records of periodic digester upsets
go back as early as 1967, but their occurrences have become less frequent since
1980, coinciding with substantial overall reductions in heavy metal concen-
trations. Past upsets directly linked to toxic metals (generally chromium) caused
increased volatile acid concentrations, increased carbon dioxide content of the
gas produced, and reduced gas production. An October, 1980 chromium spill to
the West Point facility caused a typical upset and resulted in the plant influent
chromium concentration jumping 10 fold to greater than 2 mg/1. Primary sludge
concentrations of chromium reached 710 mg/1, resulting in a 30 mg/1 increase in
digester concentrations above their normal 16-17 mg/1 level. Metro practices
sludge application to forest lands. Application rates had to be decreased during
upsets, although no interference occurred.
Figure A-5 below typifies the reduction in metals realized during the 1981-1985
time period. Plant influent chromium levels dropped approximately 55 percent
while the digested sludge concentrations were reduced by more than 40 percent.
The magnitude of these decreases are typical of other heavy metals as well,
averaging 41 percent for chromium, cadmium, copper, lead, nickel and zinc
combined (see the accompanying data sheet). The primary reason for the
reduction of cadmium and chromium concentrations is improved industrial
pretreatment. In addition to pretreatment, a less corrosive city water supply has
also resulted in lower background metal concentrations for the other metals,
especially for copper. The city recently began chemically conditioning its water
in an attempt to extend conduit life.
Success of the Metro Industrial Pretreatment Program can be attributed to a
number of important factors including:
development of stringent local limits for industrial discharges;
year-round industrial waste sampling programs supported financially
by industry; and
A-24
-------
follow-up procedures to industrial waste spills, taking enforcement
action and levying fines when necessary.
Metro has recently implemented the following steps to improve their
pretreatment program:
information exchange with industries through the use of quarterly
newsletters and personal communication, and
increasing public awareness of industrial discharge violators by
publishing the names of violating companies in local papers along
with a statement of Metro's enforcement policy.
Chromium Wast Point 1981 to 1985
O_ EFFLUENT LBS/DAX
INFLUENT LBS/DAY
V- 00 SLUDGE MG/KG
BEST LINE FIT SLUDGE
H 1
1/81 7/»l 2/82 B/12 3/»3 8/83 4/14 11/84 5/83 12/83
Tima
FIGURE A-5
WEST POINT CHROMIUM CONCENTRATIONS
A-25
-------
WEST POINT TREATMENT PLANT
SEATTLE, WASHINGTON
Design Flow:
Primary Treatment
IZSmgd
Location:
Population Served:
West-Central Washington
500,000
INFLUENT WASTEWATER
Ave. Flow, ragd
% Industrial
BO05, mg/1
SS, mg/1
Cr, mg/1
Typical (Upset)
13Z
5
160
Z60
0.05 (2.0)
Industry
Metal finishing and
electroplating
SIGNIFICANT INDUSTRIES
Problem Pollutants
Flowrate
(mgd)
1.1
Cd, Cr, Cu, Ni, Zn
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, tog/1
PLANT LOADING
Typical (Upset)
1080
1.58
75-110
60-90
Digested Sludge Metal Concentrations
Cadmium, mg/kg
Chromium, rag/kg
Copper, rng/kg
Nickel, mg/kg
Lead, mg/kg
1981 Level
45
480
1300
160
800
1985 Level
Z8
250
700
1ZO
400
PLANT PERFORMANCE
BOD5, mg/1
SS, mg/1
Cr, mg/L
Permit Limit Typical (Upset)
Summer Winter Summer Winter
135 85 110 75
1Z5 65 90 60
0.07 0.07 <0.05 (0.151
MAW
WASTE WATER.
BAR
SCREENS
_^^ PRIMARY
: QKT CHAMBERS
(4)
i I
CHLORINE
^ CONTACT
^^ CHANNELS
(2)
J
» FINAL
EFFLUENT
CENTRIFUGE
THICKENING
LAND
APPLICATION
ANAEROBIC
DIGESTERS
(3)
CENTRIFUGE
DEWATERING
(2)
A-26
-------
NEUSE RIVER WASTEWATER TREATMENT PLANT
Raleigh, North Carolina
The Raleigh case study illustrates the need for continuous survey and monitoring
even after the implementation of an industrial waste program in any dynamic
population center. In 1976, the 30 mgd Neuse River Wastewater Treatment
Plant (NRWTP) went on-line to replace the overloaded 16 mgd Walnut Creek
plant. In the early 1960's, influent BODs exceeded 300 mg/1 at Walnut Creek,
with the effluent ranging from 35 to 55 mg/1. These effluent levels violated the
Walnut Creek Plant permit, established by the state in order to protect the
quality of the Neuse River, which was used as the raw water source for the City
of Smithfield located downstream of Raleigh. Industries were encouraged to
conserve and recycle wastes, resulting in a 250 mg/1 influent BOD by the
mid-1960's. The City's first Sewer Use Ordinance was enacted in 1972, with
continual modification to comply with changes in the federal regulations. The
net effect is a current influent BOD consistently below 200 mg/1, despite an
industrial flow volume representing 25 percent of the plant flow.
The only significant industrial discharger of metals to the Walnut Creek plant
was a large electroplater whose occasional plating bath dumps were not
prohibited by a sewer use ordinance during the 1950's. Digester upsets
(decreased gas production) and high sludge metals content were traced to this
particular industry. Since dried sludge was being made available to the
community for landscaping purposes at the time, concern for the metals levels
prompted adoption of a proposed ordinance which directed the industry to
construct a physical-chemical pretreatment facility.
Two other metals-related industries have been responsible for high sludge metals
since the construction of the NRWTP. In the current facility, wet sludge is land
applied to farmland adjacent to the POTW, hence metal content is critical. In
each case (an electroplater and a printed circuit board manufacturer), the
industries were discharging levels of Cr, Ni, Zn, Pb and Cu sometimes in excess
of 1,000 mg/1, with highly variable effluent pH, and were uncooperative in
dealing with the City of Raleigh. Fining the former industry $ 1,000, and
threatening the latter with the same, provided sufficient incentive to install
pretreatment.
In the early 1980's, a producer of amino acids for Pharmaceuticals in Raleigh
discharged slug loads totaling 1,000 Ibs of NH3 to the POTW each day.
Fortunately, an activated sludge system had been constructed for their facility
for BOD reduction, which possessed sufficient capacity to nitrify their
wastewater to an ammonia concentration of 50 mg/1. On one occasion, the NHg
levels became toxic to the lU's activated sludge pretreatment, resulting in a
gradual loss of nitrification at the POTW. Rapid identification of the NH3
discharge by City personnel preserved the POTW nitrifier population, which was
subsequently used to re-seed the industry's activated sludge with a viable
nitrifier population for a speedy recovery. The rapid response prevented the
monthly effluent NH3 levels from exceeding the permit limit, despite high daily
concentrations following the incident.
A-27
-------
A dairy product manufacturer who cleans the stainless steel tanker trucks on-
site had previously discharged these wastes directly to the sewer. Average BODs
of 10,000 mg/1, with occasional values in the 30,000 to 40,000 mg/1 range were
typical, often resulting in effluent BODs in excess of the 6 mg/1 (12 in winter)
allowed for the POTW. Working with the North Carolina State University, a
vacuum recovery system was developed and a market identified for the collected
whey waste. The effluent BOD now averages 2,000 mg/1, still resulting in a high
surcharge payment, but no permit violations at the POTW.
An unusual case at the NRWTP was the discovery of high zinc levels (1,000 mg/1)
in the discharge from an office building with no manufacturing component.
Through discussions with maintenance personnel, the City of Raleigh discovered
that the contaminated discharges corresponded to floor stripping activities in the
building. They learned that a Zn-based floor wax had been used, and stripping an
entire office building over the course of a week discharged enough Zn to the
POTW to significantly raise the level in their sludge. The elevated zinc level
threatened to interfere with the POTW's ability to dispose of its sludge.
The Raleigh plant is currently under construction to increase the hydraulic
capacity from 30 to 40 mgd, with an additional expansion to 60 mgd planned for
the near future (the schematic shown on the next page is for the 40 mgd
facility). The rapid growth of this community will continue to bring with it a
variety of challenging new industrial wastewaters with, in some cases, unpredict-
able impacts on the POTW.
A-28
-------
NEUSE RIVER WASTEWATER TREATMENT PLANT
RALEIGH, NORTH CAROLINA
Design Flow: 40 mgd Location: Central North Carolina
Secondary Treatment: Activated Sludge Population Served: 195,000
(Extended Aeration)
INFLUENT WASTEWATER
Ave. Flow, mgd
% Industrial
BODj, mg/1
SS, mg/1
Typical (Upset)
25
25
165 (350)
170 (500)
Industry
Electroplaters, Metal
Finishers (5)
Pharmaceutical
Dairy
Snack Foods
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd) Problem Pollutants
750 Cd, Cr, Cu, Ni, Pb, Zn, Cn", Fe, pH
400 NH3
110 BOD
100 BOD
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, Hours
SVI, ml/gm
Effluent BODg, mg/1
Effluent SS, mg/1
Effluent NH3, mg/1
PLANT LOADING
Typical (Upset) Aeration Basins
650
3.0
Typical (Upset)
680
3.3
150-200 (250)
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Return Flow, %
D.O. Level, mg/1
Multi-Media Filters
Hydraulic loading, gpm/sf
PLANT PERFORMANCE
Permit Limit
Summer Winter
Typical (Upset)
Typical (Upset)
0.08-0.10
12-20
2500
15
50
Typical (Upset)
2.5
BOD5, mg/1
SS, mg/1
NH3, mg/1
6
30
3
12
30
6
3 (15)
4
1.5 (8)
RAW
WAStEWATER
AR SCREEN*
AND
OMT CHAMBER
EFFLUENT
HAS
LAND
APPLICATION
A-29
-------
NEWARK WASTEWATER TREATMENT PLANT
Newark, Ohio
The Newark Wastewater Treatment Plant (NWTP) had been in substantial non-
compliance with its 1981 NPDES permit from the beginning of 1983 until the
middle of 1984. This consistent violation had resulted primarily from increased
waste loads on the POTW from industrial sources. Between 1979 and 1984, the
percentage of industrial wastewater increased from 12 to 22 percent by volume,
with influent BOD increasing from 220 to 330 mg/1, while suspended solids
increased from 200 to 350 mg/1. To complicate the non-compliance problem,
four separate ammonia discharge episodes occurred from August to October,
1983 which resulted in both the loss of activated sludge viability (interference)
and the pass-through of the NH3 and the subsequent killing of 80,000 fish in the
Licking River. The fish kill precipitated the submission of Verified Complaints
to the Ohio EPA on August 6, 1984 by the Black Hand Gorge Preservation
Association, against the City of Newark and the NWTP. Following an
investigation, the Ohio EPA issued Director's Final Findings and Orders,
specifying a compliance schedule and interim discharge limits for the POTW
until a planned facility upgrade is completed by July 1988.
There are two significant industrial contributors to the NWTP who were also
issued Director's Final Findings and Orders in May, 1985. A fiberglas insulation
manufacturer had been discharging high concentrations of phenol (2-5 mg/1) and
NH3 (up to 500 mg/1), with occasional spills of formaldehyde into the collection
system. The activated sludge bacteria were acclimated to the phenol in the
wastewater, but were susceptible to interference from shock loadings of the NH3
and formaldehyde. Fortunately, the industry was responsive to the problems of
the NWTP, and instituted a corrective program to:
conserve and recycle plant flows, which have reduced their discharge
by 60 percent (from 1.22 to 0.45 mgd) over the past two years;
construct an aerated equalization basin to air-strip phenol and
distribute diurnal fluctuations; and
construct a pretreatment facility for their landfill leachate.
The POTW is still subject to occasionally high NH3 loads from the industry,
which is currently the only identifiable cause of isolated interference problems
in the plant. The municipality and industry continue to work cooperatively to
resolve this problem through the implementation of a spill prevention and control
program. Additionally, the renovated POTW will use some of the existing
clarifier tankage for off-line storage in the event of future spill episodes.
The replacement of coarse bubble aerators with fine bubble equipment in mid-
1984 significantly improved BOD removals and the NWTP compliance record.
Nitrification, which did not occur previously, now takes place in the last two
aeration basins, because of the improved carbonaceous BOD (CBOD) removal in
the initial basins. The only incident of non-compliance with the interim permit
in 1985 resulted from an NH3 discharge from the fiberglass manufacturer. In
A-30
-------
this case, even though the average monthly BOD measured 29 mg/1, the
carbonaceous component was less than 10 tng/1. The final permit will have a
more stringent NH3 requirement and will also designate CBOD as a permitted
parameter.
A second major industry is a dairy which came on-line in 1976. Initially, the
dairy stored whey waste in a silo and typically bled it into the sewer system.
The discharge was high in both BOD and suspended solids (Z,000 mg/1), and would
occasionally be batch discharged to the POTW, resulting in a shock loading to the
activated sludge and violation of the NPDES permit limits. The industry has
since installed a reverse osmosis treatment system for the whey waste which has
reduced the solids and organic loading to the plant.
The only categorical industry that currently discharges to NWTP is an electro-
plater who constructed a metals removal system in conformance with federal
pretreatment regulations. In the past, dewatered sludge had been applied to corn
fields adjacent to the plant property. However, when heavy metals were
detected in seven of ten monitoring wells, Newark began hauling liquid sludge
off-site. The planned facility upgrade will include installation of belt filter
presses, so that the existing sludge (with acceptable levels of heavy metals) can
once again be dewatered and more economically hauled off-site to farm land.
A-31
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NEWARK WASTEWATER TREATMENT PLANT
NEWARK, OHIO
Design Flow:
Secondary Treatment:
8.0 (1Z.O Hydraulic) mgd
Activated Sludge
(Conventional)
Location: Central Ohio
Population Served: 41,000
INFLUENT WASTEWATER
Typical (Upset)
Ave. Flow, ragd 7 . 5
% Industrial 1 5
BOD5, mg/1 305 (450)
SS, mg/1 360 (550)
NH3, mi/1 35 (60)
SIGNIFICANT INDUSTRIES
Industry
Fiberglass
Dairy
Electroplater
Flowrate
(1000 gpd)
450
223
97
Problem Pollutants
Phenol, NH3, Formaldehyde
BOD, Phosphorus, SS
Cr, Cd, Pb, Ni, Zn, Cyanide
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, mg/1
Secondary Clarifiers
Overflow Rate, gal/sf/dav
Detention Time, hours
SVT, ml/gm
Typical (Upset)
560
3.2
194 (280)
147 (218)
Typical (Upset)
500
3.7
150 (350)
PLANT LOADING
Aeration Basins
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Retun Flow, %
D.O. Level, mg/1
Typical (Upset)
0.25 (0.4)
5-6
2,000
6.3
50
2.0
s, mg/1
SS, mg/1
NH3, mg/1 (Summer)
PLANT PERFORMANCE
Permit Limit
20
40
25
Typical (Upset)
13 (60)
n (95)
15 (30)
RAW
WASTEWATER
BAR
SCREENS
WAS
V7
AERATED
QRIT
CHAMBER
R
PRIMARY
CLARIFIERS
(7)
A9 |
1
f,
AERATION
BASINS
(6)
/ANAEROBIC)
DIGESTERS
(3)
LIQUID
SLUDGE
HAULING
A-32
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NORTH SHORE SANITARY DISTRICT GURNEE PLANT
Gurnee, Illinois
The Gurnee Plant of the North Shore Sanitary District (NSSDGP) receives an
average daily wastewater flow of 1Z.4 mgd from a variety of sources. Those
sources include a major naval installation, domestic sewage discharges,
secondary effluent from the District's North Chicago Sewage Treatment Plant,
and other industries which contribute 17 percent of the total flow.
Since startup in 1976, the NSSDGP has experienced periodic failures at achieving
nitrification in the two-stage activated sludge system. The failures to achieve
nitrification to the ammonia levels of the District's NPDES effluent limits have
also, at times, been accompanied by general process upsets which have resulted
in effluent SS and BOD5 violations. One of the major industrial contributors to
the Gurnee Plant, a pharmaceutical manufacturer discharging an average flow of
750,000 gpd, has similarly experienced upsets of its own activated sludge
pretreatment system which have resulted in violations of the District's local
sewer use ordinance. It was initially believed that the observed interferences at
the NSSDGP were the result of the discharge of filamentous organisms and other
solids by the manufacturer. The initiation of in-plant solids control methods
(which significantly lessened the quantity of solids entering the industrial
wastewater pretreatment system) and pretreatment system upgrades did not,
however, eliminate interferences at the NSSDGP.
In 1980, District personnel began to suspect that the presence of a nitrification
inhibiting antibiotic, erythromycin, in the pharmaceutical wastewater was the
main cause of the process upsets at the NSSDGP. By 1983, test and control
bench-scale activated sludge reactors were placed in operation and the effects
of the pharmaceutical wastewater and erythromycin on the NSSDGP were
investigated. A bioassay test for the presence of erythromycin and other
nitrification inhibitors was also developed, along with a Direct Insertion
Probe/Mass Spectrometric technique for confirmation. The results of the bench-
scale testing indicated that the presence of soluble and/or solid constituents of
the pretreated pharmaceutical wastewater inhibited nitrification and, at high
levels, could completely suppress nitrification. Additionally, it was found that
although erythromycin inhibited nitrification, acclimation to low concentrations
of erythromycin could occur in the absence of extreme concentration
fluctuations.
During January of 1984, an observed average industrial pretreatment effluent
erythromycin concentration of 53 mg/1 with mass loading fluctuations of greater
than two orders of magnitude completely inhibited nitrification in the Gurnee
Plant. The resulting BOD5 and SS concentrations were as high as 26 mg/1 and
67 mg/1, respectively. Lower concentrations of erythromycin in the absence of
such strong concentration fluctuations did not interfere with the performance of
the Gurnee Plant during August of 1984, with average effluent BODs and SS
concentrations of 11 mg/1 and 8 mg/1, respectively, and effluent ammonia
concentrations ranging from 0.4 mg/1 to 1.5 mg/1 as N. Experience at the
Gurnee Plant and with the bench-scale test systems has also indicated that a lag
period of two to three mean cell residence times is required before the effects
A-33
-------
of erythromycin on the activated sludge process become apparent. Erythromycin
also was found to disrupt the settling of the first-stage carbonaceous organisms.
Measures undertaken by District personnel to lessen the effect of the
pharmaceutical discharge on plant performance have included:
The addition of inorganic coagulants to aid primary clarifier
performance;
the addition of polymer to the first-stage activated sludge system,
daily bacterial (staphylococcus aureus) bioassays of industrial
wastewaters for the presence of inhibiting substances; and
the development of an ordinance governing the discharge of
erythromycin to the NSSDGP.
Since passage of the ordinance in November, 1985, in which the discharge limits
for erythromycin were established, the NSSDGP has substantially been in
compliance with its NPDES permit and ammonia levels of 0.25 mg/1 to 1 mg/1 as
N have been consistently achieved.
A-34
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NORTH SHORE SANITARY DISTRICT GURNEE PLANT
GURNEE, ILLIONOIS
Design Flow:
Secondary Treatment:
13.8 mgd
Activated Sludge
(Two-Stage, Modified-Contact)
Location:
Population Served:
Northeastern niinoi*
65,000
INFLUENT WASTEWATER
Ave. Flow, mgd
% Industrial
BODs, mgA
SS, mg/1
NH3, mg/1
Typical (Upset)
1Z.4
37
140
180
15
Industry
Pharmaceutical
Electroplating
Chemical
Nonferrous Metals
Military Installation
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd)
750
100
170
90
3,500
Problem Pollutants
Antibiotics, SS
Cu, CN
Organics
W
PH
PLANT LOADING
Primary CUrifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODj, mg/1
Effluent SS, mg/1
First Stage CUrifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Second Stage CUrifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Typical (Upset)
695
2.7
100
100
Typical (Upset)
780
2.5
Typical (upset)
645
3.1
First Stage Aeration Basins Typical (Upset)
F/M, Ibs BODj/lbs MLVSS/day 0.95
MCRT, days 7
MLSS, mg/1 3000
Detention Time, hours 4.2
Return Flow, % 25
D.O. Level, mg/1 2.5
Second Stage Aeration Basins Typical (Upset)
F/M, Ibs NH3-N/lbs MLVSS/day 0.07
MCRT, days 13
MLSS, mg/1 3500
Detention Time, hours 5.8
Return Flow, % 50
D.O. Levels, mg/1 2.5
BOD5, mg/1
SS, mg/1
NH3, mg/1 (summer)
PLANT PERFORMANCE
Permit Limit
10
12
1.5
Typical (Upset)
5 (17)
5 (23)
0.5 (15)
MAW
WASTEWATIR
I POLYMER
FINAL
EFFLUENT
TO
CENTRALIZED
DEWATERINO
FACILITY
A-35
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PASSAIC VALLEY WASTEWATER TREATMENT PLANT
Newark, New Jersey
Coping with industrial waste discharges to a 300 mgd POTW in a highly
industrialized area is a challenging task. The Passaic Valley Sewerage
Commissioners (PCSC) maintain an industrial waste control staff to monitor
nearly 400 industries that contribute 20 percent of the wastewater volume and
50 percent of the waste strength. The PVSC performed their first Industrial
Waste Survey for database development in 1972, and adopted a set of Rules and
Regulations (including local limits) in 1976. By 1982, a comprehensive system
consistent with the Federal Clean Water Act of 1977 had been adopted, which
established uniform user fees for mass and volumetric loadings in the Passaic
Valley plant.
The influent wastewater to the POTW is considered a high-strength waste, with
typical BOD and TSS values of 290 and 450 mg/1, respectively. Despite the
strength of the influent, the plant is close to meeting the 30/30 NPDES discharge
limits, even though the primary clarifiers are not scheduled to go on-line until
later this year (1986). The high percentage of industrial flow volume is
responsible for the high influent BOD, and hence an interference exists, although
the number of industries makes it impossible at this time to determine which are
responsible for the interference. The PVSC believes that the addition of primary
treatment coupled with the economic incentives for pretreatment created by the
user charge system will reduce the effluent to consistently below the limits.
The individual constituents of concern to the PVSC fall into three general
categories:
metals
flammables
fibers
The sources of heavy metals are chemical manufacturers, platers and tanneries.
One of the smaller (30,000 gpd) chemical companies had been identified as a
significant contributor (120 Ibs/day) of mercury to the POTW. Although the
mercury level of 50 ug/1 at the influent was not inhibitory to the activated
sludge, the concentration of mercury in the sludge limited the municipality's
disposal options. It is anticipated that ocean disposal of sludge will not be
permitted much longer, which will require the PVSC to incinerate. The Federal
Air Pollution Standards limit the mercury discharge to 3,200 g/day, which
translates into a local limit of 0.4 Ibs/day in the wastewater from the industry in
question. The chemical company responded by isolating the relevant process
streams and utilizing a batch recovery system for the mercury, reducing the
discharge from 120 down to 5 Ibs/day. When ocean disposal is formally
eliminated as a disposal option, the company can employ carbon treatment for
removal of the remaining mercury.
The oxidation of trivalent chromium to the hexavalent form in a POTW sludge
incinerator is a problem caused by the chromium-laden discharge from various
industrial users. An additional problem caused by the tanning industrial category
A-36
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is the clogging of local sewers that results from hides being inadvertently
discharged from the companies. Similar clogging problems existed at the
pretreatment plant due to the balled-up fibers from the pulp and paper
manufacturers which close off sludge return lines, orifices and nozzles. This
condition improved substantially when the moving-bridge primary clarifiers were
placed in service in December, 1985.
The Passaic Valley plant had a. unique problem with high concentrations of
flammable materials in the influent wastewater. The lower explosive limit (LEL)
is defined as the "lowest concentration of a combustible substance in air through
which a flame, once ignited, will continue to propogate". When a wastewater
approaches 50 percent of the LEL, it is important that it not be discharged into
the sewer collection system. The pure oxygen process has a control built into
the system which vents all oxygen away from the activated sludge treatment
process when high LEL is detected. Since the venting of the oxygen reduces the
treatment efficiency it can result in a permit violation as well as creating a
health hazard.
The PVSC instituted a three-part program in October of 1984 to mitigate the
problems of flammables:
required industries using or manufacturing solvents which come in
contact with discharged wastewater to install LEL detection
instruments, and to provide pretreatment to isolate the flammables if
high LELs were detected;
surveyed other industries which used solvents but had no such
discharge to determine if a potential existed, requiring necessary
control mechanisms; and
monitored the collection system more closely for illegal dumping of
such chemicals.
Representatives of Passaic Valley made it clear that a cooperative attitude on
the part of industry was an important factor in successful mitigation of
interference problems. In fact, it was the local pharmaceutical manfacturer
that conducted the research resulting in the type of LEL instrument
recommended by the Advisory Committee when the LEL regulation was adopted.
A-37
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PASSAIC VALLEY WASTEWATER TREATMENT PLANT
Newark, New Jemr
Design Flow:
Secondary Treatment:
330 mgd
Activated Sludge
(PoreOrytea)
Location:
Population Served:
Adjacent to Newark Bay
l.SMillke)
WFLOENT WASTEWATER
Typical
-------
SIOUX CITY WASTE TREATMENT PLANT (SCWTP)
Sioux City, Iowa
The Sioux City Waste Treatment Plant (SCWTP) treats a combined industrial and
municipal wastewater average flow of 13.5 mgd and discharges to the Missouri
River. More than 140 industries were identified by an industrial survey as
potential sources of wastewater. Of these, four are categorical metal finishing
or electroplating industries and, as of recently, eleven industries contributed
significantly to the suspended solids, BOD and oil and grease discharged to the
SCWTP. Although the total volumetric load of the industrial wastewater is
typically less than 10 percent of the total flow, the industrial organic loads to
the plant account for greater than 50 percent of the observed loads.
The SCWTP has experienced two separate incidents in which industrial
discharges have interfered with normal plant operations. Isolated slug loads of
zinc were experienced by the SCWTP in March and again in April of 1984.
Levels as high as 16 mg/1 Zn were observed in the treatment plant influent and
both slug-load incidents resulted in an upset of the activated sludge process and
violations of the NPDES discharge limits. Effluent BODg concentrations
exceeded 60 mg/1 and effluent suspended solids concentrations in excess of
200 mg/1 were observed. The investigation of the first slug load of zinc was
somewhat hampered by the lack of in-house capabilities for metals analysis and
the first indication of a contamination problem was the process upset itself.
Upon confirmation of the nature of the interference, a temporary system for the
continuous addition of lime to the primary clarifiers, which would result in the
precipitation of subsequent slug loads of zinc, was installed and operated until
such time that frequent and periodic monitoring and analysis of the influent for
metals could be performed at the SCWTP.
The source of the metal discharge was identified from the City's industrial use
survey and from samples of wastewater and solids collected at specific locations
in the wastewater collection system. The floor drain at the manufacturing
facility through which the zinc discharges occurred was disconnected from the
sanitary sewer. In addition to the process upsets, several years accumulation of
sludge held in storage lagoons and slated for disposal by land application became
contaminated with zinc. Upon receipt of special permitting from the State, the
SCWTP was allowed to dispose of the sludge as planned.
In 1985, a pharmaceutical manufacturer came on-line discharging batches of high
strength waste without pretreatment. The strength of the waste ranged from
10,000 to 100,000 mg BODs/1 and the waste contained high levels of salt and
sulfite. The average BODs of the waste was 35,000 mg/1 and the batch dumps
represented 45 percent of the total organic load to the SCWTP. The activated
sludge process was severely overloaded and intermittent depressions of the D.O.
level occurred. It was possible to operate the activated sludge process to
accommodate the severe organic loads, but the process would again be upset
during the weekends when the pharmaceutical manufacturer was not discharging
waste and the organic loads were reduced. Throughout 1985, the SCWTP
experienced severe violations of their NPDES 6005 and suspended solids
discharge limits. Frequent violations of the pharmaceutical manufacturer's
A-39
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discharge permit occurred with respect to the organic strength and daily mass
loading of the waste. The industrial user was placed on a compliance schedule
and continued violations of the discharge permit necessitated actions that would
result in flow equalization and reductions in the levels of methyl mercaptan,
sulfite and sulfide. Presently, all batch waste dumps are transported by bulk to
the SCWTP where they are metered, by SCWTP personnel, into the plant influent
under controlled conditions.
The upset conditions presented in the following table represent conditions
related to the discharge of the pharmaceutical wastewater. The reported upset
conditions represent averages for several months of 1985 whereas the typical
conditions were based on data for 1984 which spanned nine months and included
those months in which the slug loads of zinc were experienced.
A-40
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SIOUX CITY WASTE TREATMENT PLANT
SIOUX CITY, IOWA
Design Flow:
Secondary Treatment:
30mgd
Activated Sludge
(Conventional)
Location:
Population Served:
Northwest Iowa
135,000
INFLUENT WASTEWATER
Ave. Flow, mgd
% Industrial
BODj, mg/1
SS, mg/1
Typical (Upset)
13.5
7
380(612)
550 (630)
Industry
Meat Processing
Pharmaceutical
Metal Finishing
SIGNIFICANT INDUSTRIES
Flowrate
(1000 gpd)
1,000
70
20
Problem Pollutants
BOD5, oil and grease, SS
BODg, methyl mecaptan, sulfite
Zn, Cr, Ni
PLANT LOADING
Primary Clarifien
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, mg/1
Secondary Clarifien
Overflow Rate, gal/sf/day
Detention Time, hours
SVI, ml/gm
Typical (Upset)
577
2.9
220 (370)
240 (235)
Typical (Upset)
722
3
150
Aeration Basins
F/M, Ibs BOD5/lbs MLSS/day
MCRT, days
MLSS, mg/1
Detention Time, hours
Return Flow, %
D.O. Level, mg/1
Typical (Upset)
0.2 (0.3)
10
2500
15
40
2.5
s, mB/l
SS, mg/1
PLANT PERFORMANCE
Permit Limit
30
30
Typical (Upset)
34 (37)
33 (45)
MAW
WA4TIWATER
AN SCREENS
AND
OMT CHANNELS
T pr
FINAL
EFFLUENT
MI-
t
PRIMARY
CLARIFIED*
(4)
AERATION !
rANKS 1
u> '
RAS
PRIMARY
EST
(4)
DK3E8TER8J
(4)
8LUDQE LAGOONS
A-41
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TOLLESON WASTEWATER TREATMENT PLANT
Tolleson, Arizona
The Tolleson Wastewater Treatment Plant (TWTP) is a two stage trickling filter
plant that treats a predominantly domestic wastewater from Phoenix, Arizona
suburbs. The successful operation of the TWTP is dependent on the one
significant industrial contributor to the treatment plant, a meatpacker who
processes 1,000 to 1,400 head of beef per day.
The influent to the TWTP could be typified as medium to high-strength municipal
wastewater with average BOD 5 and SS levels being 275 mg/1 and 225 mg/1,
respectively. Approximately 25 to 30 percent of the average organic and solids
loading is contributed by the meatpacker average at levels of 1,100-1,600 mg/1
BODs and 700-1,200 mg/1 SS, for wastewater flows of 0.8-1.0 mgd. In general,
the domestic/industrial waste stream BODs, and SS can both be treated to below
10 mg/1, well within the 30/30 discharge limits. However, hi the past the
meatpacker has upset the treatment process by slug discharging blood or other
high strength organic slaughter by-products with BODs anc^ ^3 levels of up to
2,200 mg/1 and 1,375 mg/1, respectively. Prior to 1982, these upset conditions
would last for several days and result in weekly and monthly effluent suspended
solids of 30-40 mg/1, in violation of permit limits.
Treatment upsets have diminished in frequency and intensity since 1982 for two
reasons:
A legal contract with the meatpacker limits flow to 0.8 mgd,
to 10,675 Ibs per day (1,600 mg/1) and SS to 6,670 Ibs per day
(1,000 mg/1), and provides for fines or disconnection if these limits
are exceeded, and
Improved treatment plant process monitoring has enabled operators
to better detect, and thus act on, a potentially upsetting condition.
The contract with the meat packer attempts to prevent waste blood from being
stored for more than about eight hours at a time before discharging to the sewer.
Prior practice resulted in blood being held back for up to a week at a time before
being discharged all at once.
Primarily through trial and error, the operators of the TWTP have established
several operating parameters that help them in detecting upset conditions hi the
plant. The depth of sludge in the primary clarifiers is monitored closely; a high
or rapidly increasing sludge depth is indicative of upset conditions and is caused
by the high solids content of the meatpacking waste. The mixed liquor in the
solids contact basin following the second trickling filter is monitored closely as
well, with levels above 500 mg/1 signaling possible problems. Mixed liquor
A-42
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concentrations of 1,500 mg/1 generally result in effluent suspended solids of
greater than 30 mg/1. To remedy an upset condition, primary sludge pumping
rates are manually increased above their normal levels to reduce the solids
inventory and prevent escape in the effluent.
A-43
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TOLLESON WASTEWATER TREATMENT PLANT
TOLLESON, ARIZONA
Design Flow:
Secondary Treatment:
8.3 rogd
2 Stage Trickling Filter
with Solids Contact
Location:
Population Served:
Sooth Central Arizona
65,000
INFLUENT WASTEWATER
Typical (Upset)
SIGNIFICANT INDUSTRIES
Ave. Flow, mgd
% Industrial
BOD5, mg/1
SS, mg/1
7.4
14
Z75 (340)
ZZ5 (Z80)
Industry
Meat Packer
Flowrate
(1000 gpd)
1000
Problem Pollutants
BOD, SS
PLANT LOADING
Primary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODj, mg/1
Effluent SS, mg/1
Intermediate Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Effluent BODs, mg/1
Effluent SS, mg/1
Typical (Upset)
860
1.9
160
95
Typical (Upset)
735
Z.4
30
30
First Stage Trickling Filter Typical
Hydraulic Loading, gal/sf/day 1,000
Organic Loading, Ibs BODj/lOOO cf/day 45
Recirculation, % 100
Second Stage Trickling Filter Typical
Hydraulic Loading, gal/sf/day 500
Recirculation, % 100
Secondary Clarifiers
Overflow Rate, gal/sf/day
Detention Time, hours
Typical (Upset)
480
7.4
BODj, mg/1
SS, mg/1
PLANT PERFORMANCE
Permit Limit
30
30
Typical (Upset)
9 (Z5)
9 (35)
MAW WASTIWATER
EFFLUENT TO
TURF IRRIGATION
AH VCREEN AND
OMIT CHAMBER
INTERMEDIATE
CLARIFIER* (2)
8LUOQE TO TURF FARM
A-44
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APPENDIX B
INTERFERING SUBSTANCES
CONVENTIONAL
Biochemical Oxygen Demand
Fats, Oil and Grease
METALS AND INORGANICS
Alkalinity
Ammonia
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chloride
Chromium
Cobalt
Copper
Cyanide
Iodine
Iron
Lead
Magnesium
AGRICULTURAL CHEMICALS
Aldrin/Dieldrin
Chlordane
Chlorophenoxy Herbicides
DDT
Endrin
PH
Suspended Solids
Manganese
Mercury
Molybdenum
Nickel
Nitrogen
Phosphorus
Selenium
Silver
Sodium
Sulfate
Sulfide
Sulfite
Tin
Thallium
Vanadium
Zinc
Heptachlor
Lindane
Malathion
Organometallic Pesticides
Toxaphene
AROMATICS
Benzene
Chlorobenzene
Dichlorobenzene
Dinitrotoluene
Nitrobenzene
PCBs
Toluene
Zylene
B-l
-------
HALOGENATED ALEPHAT1CS
Carbon Tetrachloride Methylene Chloride
Chloroform Tetrachlorodibenzodioxins
Chlorom ethane Tetrachlorodibenzofurans
Dichloroethane Tetrachloroethane
Dichloroethylene Tetrachloroethylene
Dichloropropane Trichloroethane
Hexachlorobutadiene Trichloroethylene
Hexachlorocyclohexane Vinyl Chloride
Hexachloroethane
NITROGEN COMPOUNDS
Acetanilide Dyes
Acetonitrile EDTA
Acrylonitrile Ethylpyridine
Aniline Fluor enamine
Benzidine Hydrazine
Benzonitrile Nitrosodiphenylamine
Chloroaniline Pyridine
Dichlorobenzidine Trisodium Nitrilotriacetate
Dimethylnitrosamine Urea
Diphenylhydrazine
OXYGENATED COMPOUNDS (Acids, Alcohols, Aldehydes, Esters, Ethers,
Ketones)
Acetone Ethylene Glycol
Acrolein Formaldehyde
Adipic Acid Esters Formic Acid
Allyl Alcohol Heptanol
Benzoic Acid Hexanol
Boric Acid Isophorone
Butanol Linoleic Acid
Butyl Benzoate Malonic Acid
Chlorobenzoate Methanol
Chloroethyl Ether Methylethyl Ketone
Cinnamic Acid Methylisobutyl Ketone
Crotonol Octanol
Cyclohexanecarboxylic Acid Polyethylene Glycols
Diethylene Glycol Polyvinyl Alcohols
Ethoxy Ethanol Protocatechuic Acid
Ethyl Acetate Syringic Acid
B-2
-------
PHENOLS
Catechol Pentachlorophenol
Chlorophenol Phenol
Cresol Trichlorophenol
Dichlorophenol Trinitrophenol
Dinitrophenol Vanillin
Nitrophenol
PHTHALATES
Dimethylphthalate
Disoctylphthalate
E thylhexylphthalat e
POLYNUCLEAR AROMATIC HYDROCARBONS
Anthracene Naphthalene
Benzo (a) Anthracene Phenanthrene
Chloronaphthalenes Pyrene
di-Isopropyhiaphthalene
B-3
tr U.S. GOVERNMENT PRINTING OFFICE: 1967 716- 0 0 2/ 60699
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