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Pretreatment is a requirement placed on some commercial and
industrial wastewater customers to provide treatment of the wastewater prior to
discharging to the wastewater collection system. These establishments may be
required to reduce wastes entering the wastewater system by installing grease
traps, oil/water separators, chemical neutralization, and/or other such methods
to prevent disruptions to the wastewater system.
What is FOG (Fats, Oils & Grease)?
FOG stands for Fats, Oils and Grease. FOG includes cooking oil, butter, margarine, bacon grease, dairy products, salad dressings, gravy, soups, sauces and other fats typically used in cooking. They can be liquid or solid. FOG can be a major problem for a wastewater system. In the kitchen, FOG comes mostly from pre-rinsing dishes or washing pots and pans.
When washing these items, FOG is poured down the drain where it cools, hardens, and sticks to the inside of the collection pipes. This produces a buildup that can cause clogs and sanitary backups in homes and businesses, or generate wastewater overflows, spills onto private property, streets, and local surface waters.
Who are the major contributors of FOG?
Restaurants and other Food Service Establishments (FSEs) are a significant source of FOG because of the amount of grease they use in cooking and other food preparation work. The Pretreatment program is intended to prevent FOG (from these commercial customers) from entering the wastewater system.
If you believe your establishment may require a pretreatment device, on is available for download.
See Application and Procedures for Grease Pretreatment Equipment Installation
How do our customers benefit from the Pretreatment program?
Limiting the amount of FOG levels entering the wastewater system helps reduce costs related to maintaining the wastewater system. The District spends a significant amount of money and man-hours unclogging and cleaning wastewater collection lines.
As these costs are ultimately passed on to the District’s customers through our wastewater rates, the less the District has to spend on FOG related issues, the less these costs are passed on to our customers.
Is Pretreatment a requirement?
Pretreatment may be required to comply with Federal and State regulations and statutes. The program is administered through the CLEAN WATER ACT of 1972 (33 U.S.C. 1251 et. Seq.) and is requirement of the United States Environmental Protection Agency (40 CFR 403).
Alderwood Water & Wastewater District’s standards and limitations of discharge materials into its wastewater system is defined through resolution SR 977-2012 These laws were enacted to protect human health and safety by limiting or prohibiting hazardous discharges to the collection system.
How will the Pretreatment program monitor my establishment?
The District conducts quarterly inspections of all pretreatment devices within our service area. Environmental Compliance Inspectors will need to look inside the pretreatment device and analyze the level of grease in the structure and determine if proper maintenance is being performed. They will also look at the outlet tee to determine if there is any grease being discharged into the sanitary sewer.
If the inspector finds any visual issues with the system, they will ask to look at the maintenance logs to determine the last time the system was serviced in order to ensure maintenance activities are being performed. The records review will determine if the District requests that a FSE increase its maintenance schedule or develop a routine schedule if needed. A Maintenance log for cleaning your establishment’s pretreatment device is available for download
What is a Surcharge?
In accordance with AWWDC 6.10.090 , samples will be collected and analyzed for FOG concentration. The surcharge will be recalculated monthly based on the concentration of FOG in the discharge.
The cost of the monthly sample analysis will also be added to the sewer charges. The surcharge will be lifted when the FOG concentration in the discharge falls below 100 mg/L.
Which Pretreatment device is right for my establishment?
All devices must be designed and sized appropriately for your establishment. The District shall approve pretreatment devices designed for the prevention of discharge of FOG into the wastewater system.
Failure to properly submit your design may result is costly revisions to the design at your expense.