Sewage backups and overflows are typically the result of fats, oils, and greases (FOG) in the sewer collection system. FOG cool and stick to the sides of sewer pipes when poured down the drain, causing backups in homes and businesses. Blockages in the sanitary sewer system can restrict flow and cause it to actually reverse and backup out of manholes and overflow into public streets, into storm drains, into rivers. If this were to occur, it could create a public health hazard.
1. How FOG Gets Into the Sewer System
Fats, oils, and greases are byproducts from cooking, packaged foods, and food scraps; it comes from meat, butter, baked goods, shortening, dressing, dairy products, etc. Flushing food down the toilet or washing cookware before properly disposing of FOG flushes it all down the drain into the sewer system.
The majority of FOG related sewer backups and spills typically occur in areas of the city where restaurants are located. About 5% of sewer blockages in Concord are caused by FOG not being properly managed. FOG gets into sewers from food preparation establishments that do not have adequate grease control measures in place, such as external grease interceptors or internal grease traps hooked to kitchen sinks. Improperly maintained grease control devices can also be the cause of excessive FOG entering the sewer collection system. Sewer blockages do occur in residential areas, although the frequency is less than in areas where restaurants are located.
2. FOG Impact
Blockages caused by improper disposal of FOG can lead to costly repairs and maintenance for the property owner and the City of Concord. FOG decreases pipe capacity and could require pipe replacement a lot sooner than anticipated. The City of Concord`s Highway and Utilities Division are responsible for maintaining the collection system to minimize blockages that can lead to sewer overflows.
If sewage were to overflow in the street, it could find its way into a catch basin and then into surface waters causing environmental, health, and safety issues. Once a backup occurs, it is a reportable incident to our Highways and Utilities Division.
3. Preventing FOG In The Sewer System
Never dump fats, oils, or greases down the sink, garbage disposal, toilet, or any other drain. Do not use hot water to rinse cookware, utensils, dishes, or surfaces. Always wipe it into the garbage prior to washing. If the FOG is still in liquid form, wait for it to dry out or freeze it to allow it to dry out quicker for disposal in the trash within a sealed container. You could also dry it out by mixing in cat litter, coffee grounds, sand, or any other kind of absorbent material.
Always be sure to use strainers in sink drains to catch food scraps and to dispose of them in the garbage. Soap may break up grease while you are washing dishes, but it dissolves as it washes down the drain and the grease solidifies on pipe walls.
Grease Removal Devices
The City of Concord has Ordinances and Regulations requiring the installation and maintenance of a Grease Removal Device(GRD) for facilities providing any type of food or drink service to help minimize FOG from entering the sewer collection system. Food Service Establishments are required to have a grease removal device, such as internal grease trap or external grease interceptor. For more information about GRDs, please, contact the City`s Code Administration Department at 603-225-8580.