A. PURPOSE AND POLICY
- City of Hobart Ordinance 2021-01: “SEWER USE ORDINANCE ESTABLISHING RULES FOR THE USE OF THE CITY’S SANITARY SEWER SYSTEM AND AN INDUSTRIAL USER PRETREATMENT PROGRAM”, sets forth uniform requirements for discharges into the Hobart Sanitary District (HSD) Wastewater Collection System which eventually discharges through the Gary Sanitary District (GSD) Collection System and into the GSD Wastewater Treatment Plant. These requirements enable the HSD to protect public health, ensure a sound sewer infrastructure system in the future, and comply with all applicable local, state and federal laws.
- Ordinance 2021-01 details the general regulation of discharges to public sewers, the issuance of discharge permits for industrial users of the system, and the enforcement of all applicable local, state, and federal laws and regulations required by the Clean Water Act, General Pretreatment Regulations (40 CFR Part 403), and consistent with the HSD's Enforcement Response Guide.
- The following indicates specific objectives regarding the HSD Pretreatment Program:
- To prevent the introduction of pollutants into the HSD's and the GSD's Wastewater Collection Systems which will interfere with the normal operation of the GSD Wastewater Treatment Plant or contaminate the resulting municipal sludge.
- To prevent the introduction of pollutants into the HSD wastewater collection system which do not receive adequate treatment in the GSD Wastewater Treatment Plant, and which will pass through the plant into receiving waters or the atmosphere, or otherwise be incompatible with the Publicly Owned Treatment Works.
- To improve the opportunity to recycle and reclaim wastewater and sludge from the system.
- To protect both the general public and city personnel who may be affected by wastewater and sludge in the course of their employment.
- To provide for fees for the equitable distribution of the cost of operation, maintenance, and improvement of the Publicly Owned Treatment Works.
- To provide for the regulation of discharges into the HSD's and GSD's wastewater systems through the issuance of industrial discharge permits, the execution of inter-jurisdictional agreements, and the enforcement of administrative regulations.
Federal, State and Local Requirements
The national pretreatment program requires nondomestic dischargers that introduce pollutants to Publicly Owned Treatment Works (POTWs) to comply with pretreatment standards to ensure the goals of the Clean Water Act (CWA) are attained. The program also outlines requirements for POTWs to proactively protect its infrastructure while overseeing its management responsibilities.
The objectives of the program are to:
- prevent the introduction of pollutants into a POTW that will interfere with its operation, including interference with its use or disposal of municipal sludge,
- prevent the introduction of pollutants into a POTW that will pass through the treatment works or otherwise be incompatible with it, and
- improve opportunities to recycle and reclaim municipal and industrial wastewaters and sludges.
The national pretreatment program identifies specific discharge standards and requirements that apply to sources of nondomestic wastewater discharged to a POTW. By reducing or eliminating waste at the industries (“source reduction”), fewer toxic pollutants are discharged to and treated by the POTWs, providing benefits to both the POTWs and the industrial users.
Local municipalities are mostly responsible for implementing and enforcing the national pretreatment program requirements. The general pretreatment regulations at 40 CFR Part 403.8(a) require certain POTWs to establish a local pretreatment program to control discharges from nondomestic sources and to prevent pass through and interference at the treatment plant. There are approximately 1,600 POTWs that have local programs.
Pretreatment Program Requirements: Development and Implementation by POTW (40 CFR Part 403.8(a)) (PDF) (7 pp, 232 K)
An industrial user (IU) is a nondomestic source of indirect discharge into a POTW. An IU must comply with all applicable federal, state, and local pretreatment standards and requirements. Some federal requirements apply to all IUs and other requirements apply only to specific types of IUs. These federal requirements apply regardless of whether the IU has a control mechanism (e.g., permit or discharge authorization) from its control authority.
- What is Pretreatment?
Beneath the streets of every city and many smaller communities, a system of sewers and pumps conveys wastewater away from homes, factories, offices, and stores. This disposed water, which may contain a variety of domestic, commercial, and industrial wastes, flows through the sewers to a wastewater treatment plant. There, pollutants are removed and the cleansed water is discharged into an adjacent water body, such as a river, bay, lake or ocean. The residues of the treatment process (biosolids) are either used productively as a soil conditioner or disposed of as a solid waste.
Industrial plants are only one of many sources of wastewater discharged into municipal sewers. But the wastewater discharged by industry is often contaminated by a variety of toxic or otherwise harmful substances not common to other sources - the by-products of industrial processes such as cyanide from electroplating shops and lead from the manufacturing of batteries. These wastes can pose serious hazards. Because sewage collection and treatment systems have not been designed to treat them, industrial wastes can damage the sewers and interfere with the operation of treatment plants, or pass through the systems untreated, resulting in contamination of nearby water bodies and increase the cost and environmental risks of sludge treatment and disposal.
The undesirable effects resulting from the discharge of industrial wastewater into municipal sewers can be prevented. Industrial plants, using proven pollution control techniques, can remove pollutants from their wastewaters before discharging them into the municipal sewage treatment system. This practice is known as "pretreatment".
2. National Pretreatment Standards
The federal government has developed national regulations or "standards" that restrict industrial pollutants discharged into sewage systems. Individual POTWs must impose limitations (via Sewer Use Ordinance) that may be stricter than the national standards, but cannot allow less stringent levels of control. The national pretreatment standards consist of two sets of rules, prohibited discharge standards and categorical pretreatment standards.
3. Prohibited Discharge Standards
The National Prohibited Discharge Standards forbid certain types of discharges by any sewage system user (40 CFR 403). The standards apply to all industrial/commercial system users whether or not they are covered by categorical pretreatment standards.
The general prohibitions forbid pollutants to be discharged into the sewage system if they pass through the POTW untreated and cause the POTW to violate its NPDES permit, or if they interfere with POTW operations (including sludge disposal).
4. Categorical Pretreatment Standards
Categorical Pretreatment Standards are pollution control regulations for specific industries. The standards regulate the level of pollutants in the wastes discharged into the sewage system from an industrial process. Each categorical standard covers one industry category and assigns specific end-of-process limits for the process waste streams covered by that specific category.
5. Additional Standards
In addition to applicable pretreatment standards, an industrial user shall comply with an effluent limitation more stringent than the applicable pretreatment standard that is necessary to prevent interference in the POTW receiving the discharge or violation of a state or federal water quality standard that is applicable to the state waters ultimately receiving the discharge from the industrial user after discharge from the POTW.
City of Hobart
See City of Hobart Ordinance 2021-02 regarding municipal code requirements.
Fats, Oils, Grease (FOG)
Grease is a problem for all of us. It doesn't break down in water and tends to separate from other liquids. This can cause problems in your pipes and ours.
As our community grows, so do the demands on public infrastructure. Sewer lines and pump stations require more frequent maintenance, wastewater treatment costs rise and sanitary sewer overflows still need to be prevented.
Oil and grease from kitchen drains accumulate in the pipe system. As grease cools, the fat hardens and pipe capacity decreases. This requires more frequent cleaning and increases maintenance costs at treatment plants. Backups in your home or business are costly, but can be reduced when you implement best management practices to keep grease out of your sink and drains.
1. Why do FOG pretreatment systems matter?
Proper installation, use and cleaning of grease interceptors can help save time and money and ensure compliance with the local sewer use ordinance.
All fixtures and drains in food service areas must be connected to an appropriately sized grease interceptor and be on an effective pump out maintenance schedule. FSEs must also ensure FOG doesn't enter the stormwater system through open trash enclosures or improper practices. When FOG enters a stormwater catch basin, it discharges directly to local creeks, wetlands and rivers – and violates the Clean Water Act.
2. How can I be sure I am in compliance with the ordinance?
- Connect all food and beverage service area faucets and drains to an appropriate-sized grease interceptor.
- Maintain your grease interceptor to prevent FOG bypass accumulation before storage capacity is full.
- Keep maintenance records for inspection by city staff.
3. What is FOG Best Management Practices?
- Keep wash practices in areas that don’t drain to a storm catch basin. Only rain water should enter the storm drain.
- Scrape all FOG and food solids from dishware and cookware into trash before washed.
- Install properly sized screens for all drains to prevent solids and foreign objects from getting into the sanitary system.
- Don't use degreasers or emulsifiers in your building sewer system.
- Clean vent hoods and filters as needed.
- Prevent spillage when transferring cooking oil to an outside oil waste bin.
- Cover trash enclosures. If there is a catch basin in the trash area it should be coved and connected to a grease interceptor.
4. Do I need a grease interceptor?
Yes, if your facility qualifies as a Food Service Establishment as: "A facility that engages in activities of preparing or serving food or beverage for consumption either on or off the premises, including but not limited to restaurants, cafes, commercial kitchens, caterers, hotels/motels, schools, hospitals, prisons, correction facilities, nursing homes, care institutions, and any other facility preparing and or serving food/beverage shall have a Pretreatment system (Grease Interceptor) to protect the public sewer."
5. What is a grease interceptor and how does it work?
A grease interceptor captures wastewater discharge from fixtures and drains in a food/beverage service area and is connected to the building sewer. A grease interceptor is intended to slow the wastewater discharge long enough (retention time) for the FOG and food solids to separate from the gray water. The FOG floats to the top and food solids sink to the bottom, allowing gray water to pass through to the public sanitary sewer system properly.
The gray water discharge travels through conveyance (pipes/pump stations) and on to a wastewater treatment plant for processing. Grease interceptors need to be installed so that all areas that contact wastewater can be properly maintained and visually inspected.
6. What types of grease interceptors can be used?
The food/beverage service industry utilizes two main types of grease interceptors:
- Gravity Grease Interceptor (GGI) is a large vault made of concrete or plastic. It has the largest FOG storage capacity with at least two internal chambers and is installed outside. A gravity grease interceptor allows wastewater to reach the first chamber, the inlet bay. It is where FOG and food solids are stored and separated from the gray water through retention time process. The gray water then continues on to the second chamber, the outlet bay, for further separating. The outlet bay is not intended to store FOG, but to provide an indicator of service needed to comply with the Local Sewer Use Ordinance.
- Hydromechanical Grease Interceptor (HGI) is smaller and made of plastic or metal. HGI uses an internal baffle system with flow control to hold wastewater in the building sewer until the HGI has time to process (retention time) FOG and food solids from the gray water. This process can lead to a FOG buildup in your building system. HGI needs easy access for maintenance and visual inspection.
It's important to note:
- FOG storage capacity will determine long-term maintenance costs.
- Consider capital costs (short term) vs maintenance costs (long term)