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Publicly Owned Treatment Works: P2 Opportunities
Sector Guidance from EBMUD
The East Bay Municiple Utility District has a series of guidance documents for sectors that discharg...
Pollution prevention opportunities abound for POTWs. However, the P2 opportunity
that is the focus of this topic hub is:
- Pretreatment programs designed to reduce the toxicity of the waste stream
focusing on industrial wastes and fecal wastes
What Is A Pretreatment Program?
Federal law mandates pretreatment Programs. The Regional Water Quality Board
mandates the Program as part of the SCRWA Plant's permit to operate and discharge.
The Program's intent is to control pollutants discharged to a Publicly Owned
Treatment Works (POTW) from non-domestic sources. The Clean Water Act of 1972
sets forth the following objectives:
- To prevent upset, interference(1) and pass-through(2) in the POTW. Specifically,
the SCWRA Plant.
- Provide protection with regard to the health and safety of the public and
- Provide protection of the structure and integrity of the collection system
and safety for the
personnel working the system.
- To prevent deterioration of the quality standards of the receiving waters;
to prevent contamination
of POTW sludge which could affect their disposal or future use.
1 Interference - A discharge by an Industrial User which
inhibits or disrupts the treatment plant processes or operations.
Pass-Through - The discharge of pollutants through the treatment plant which
causes a violation of any requirement of the treatment plant's permit from the
State regulatory agency (the Regional Water Quality Control Board).
What is Source Control?
Source control is a term used to describe activities which reduce or eliminate
wastewater and pollutants that would otherwise exit the manufacturing process
and enter the wastewater treatment facility. One approach to source control,
pollution prevention, focuses on preventing the generation of wastes, while
waste minimization refers to reducing the volume or toxicity of hazardous wastes.
While individuals and homeowners contribute to pollution that enters municipal
POTWs, industrial users are the largest contributors. For information on source
control for homeowners and individuals, click here: P2
Tips for Household Hazardous Waste.
Pretreatment limits may be met by industry through pollution prevention/waste
minimization (e.g. material substitution, recycling and reuse of materials,
treatment or process modification). These efforts may also be termed source
The benefits of source control in addition to protection of the public and
the environment are cost savings to the industry as a result of reduced chemical
and water use, reduction in disposal costs and liability, and potential reduction
in the size of a pretreatment system.
What are the objectives of the Pretreatment Program?
There are three primary reasons:
- To prevent the introduction of pollutants into POTWs that will interfere
operation o f the POTW, including interference with its use or disposal of
- To prevent the introduction of pollutants into POTWs that will pass through
incompatible with the treatment works;
- To improve opportunities to recycle and reclaim municipal and industrial
What Does Pretreatment Mean?
Pretreatment is the reduction of the amount of pollutants, the elimination of
pollutants, or the alteration of the nature of pollutants in wastewater to a
less harmful state prior to discharge to the treatment plant.
How Is the Pretreatment Program Implemented?
The Pretreatment Program is implemented through the Industrial Waste Discharge
permit issued to businesses. The program is implemented through three elements
in the permit: prohibited discharge standards, national categorical standards,
and local limits. Permit conditions are authorized by Chapter 19 of the Gilroy
City Ordinance and Chapter 13 of the Morgan Hill City Ordinance.
Who Is Required To Have An Industrial Waste Discharge Permit?
All existing commercial, institutional, and industrial users of the public sanitary
sewer system. Examples: restaurants, hospitals, car wash, dental offices, medical
offices, dry cleaners, printing shops, electronic components firms, etc.
What Is An Industrial User?
An industrial user is any non-residential discharger. An industrial user may
not have any industrial wastewater, and may only have regular (domestic) sewage.
However the pretreatment program applies to all non-residential dischargers
because they have the potential to discharge other wastes to the system.
What Is An Industrial Waste?
Any non-domestic liquid or solid waste from any producing, manufacturing, processing
or operation of a commercial, industrial, or institutional establishment of
whatever nature. Industrial waste is distinct from sanitary or domestic waste.
When Are Industrial Users Required To Obtain A Permit?
All industrial users proposing to connect to or to contribute to the municipal
sanitary sewer system shall obtain an industrial waste discharge permit before
connecting to or contributing to the municipal sewer system. The Program, however,
only issues a permit certificate to actual dischargers that actually have an
industrial waste. Many users of the system, like a retail shop or an office,
may not have to obtain a permit certificate. This assessment is made during
the Business License application and building permit application processes.
See the list below for examples of businesses that have to obtain a permit certificate.
- Vehicle Related Businesses (Automotive, Aircraft, Boat, Truck or Tractor):
Washing, Steam Cleaning, Parts Washing, Radiator Repair, Detailing, Painting,
- Any Commercial Cooking: Bakeries, Caterers, Deli's, Restaurants, Fast Food
Halls And Auditoriums With Kitchens
- Cleaners, Dry Cleaners, Laundries, Laundromats
- Food Processing, including Breweries, Dairies, Wineries
- Furniture: Repair, Painting, Stripping
- Hospitals: Convalescent, Medical, Emergency, Veterinary
- Animal Care: Kennels, Grooming
- Laboratories: Chemical, Medical, Research and Development
- Medical: Chiropractors, Dentists, Physicians, Veterinarians
- Paper, Wood or Metal Processing, Cutting, Machining, Coating, Painting,
- Photography: Film Processing, X-Ray Developing, Dark Rooms
- Art Studious: Ceramics, Painting, Pottery
- Printing/Copy Shops
Industrial Wastewater Treatment Methods
There are three general treatment methods for industrial wastewaters: Physical,
chemical and biological treatment. Physical treatment methods consist of processes
such as membrane technologies, carbon adsorption, distillation, filtration,
ion exchange, oil and grease skimming, oil/water separation, sedimentation,
steam stripping, and solvent extraction. Membrane technologies, such as ultrafiltration
and microfiltration are currently popular physical treatment technologies. Chemical
treatment methods include: Chemical oxidation, chemical precipitation, chromium
reduction, coagulation, cyanide destruction, dissolved air flotation electrochemical
oxidation, flocculation, hydrolysis, and neutralization (pH control). Biological
treatment methods include: biological nitrogen removal, bioaugmentation, activated
sludge, extended aeration, anaerobic processes, rotating biological contactors,
sequencing batch reactors and trickling filters.
Water Reuse, Pollution Prevention and Waste Minimization
For many industries water reuse, pollution prevention and waste minimization
are being increasingly utilized. Pollution prevention, focuses on preventing
the generation of wastes, while waste minimization refers to reducing the volume
or toxicity of hazardous wastes. Water reuse involves reusing or treating and
reusing wastewater in manufacturing or other processes at a facility. Many companies
are also substituting materials used in production processes with more environmentally
friendly materials. Industries are now realizing that a leaner, greener, and
safer company can also contribute to cost savings, positive recognition and
customer satisfaction. Regulatory agencies are finding ways to reduce regulatory
burdens for "green industries".
Industrial User Evaluation/Pretreatment Programs
Working closely with your industries creates an awareness on both sides of potential
problems and the cause and effect of industrial discharges on the treatment
plant. A good relationship with your industries also fosters communication which
can help reduce the impact of problems that do occur. It also gives you the
opportunity to promote pollution prevention within your community.
- Regularly update your industrial user survey to determine what industries
are tributary to the POTW (and/or CSOs).
- Identify the pollutants of most concern and the industries most likely
a source of those pollutants.
- Target one or more industrial groups per year for pollution.
- Schedule a workshop/training/brainstorming session with one or more industries.
- Incorporate voluntary P2 conditions into permits and renewals, as well as
agreements and corrective action plans.
- Train industrial inspectors in basic pollution prevention, particularly
in the types of industries
that operate in your municipality. This can also include other inspectors,
including fire department
personnel and city code inspectors.
- Incorporate pollution prevention advice into routine pretreatment inspections
(e.g. less hazardous parts
cleaning methods, equipment cleaning and maintenance practices, reuse of materials,
- Encourage hazardous waste generators to participate in pollution prevention
- Promote material exchange between industries for usable waste materials
(pallets, packaging materials,
still usable chemicals and byproducts of production are examples).
For industry specific tips on Pollution Prevention, click
P2 OPPORTUNITIES BY CHEMICAL
A critical element of any successful pre-treatment program is chemical-specific
information that is available to both POTW employees and the industry in general.
The provided list details information on both the environmental hazards and
the P2 opportunities associated with certain chemicals. A list of references
and help sites is also included. Click
here for more information
City of Gilroy, Ca. http://www.ci.gilroy.ca.us/
EPA - Effluent Guidelines - Zero Discharge http://www.epa.gov/ost/guide/p2/faqs2.htm
EPA - Mercury Pollution Prevention at POTWs and other Resources
Illinois Environmental Protection Agency – Pollution Prevention for POTWs
Pretreatment Program Home Page
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