Fats, oils, and grease (often referred to as FOG) are universal problem substances in wastewater. Most FOG is not soluble; meaning it does not mix well with water. Due to this, FOG floats on water and clings to surface areas void of water. This is why grease collects on the top of drain lines first. As additional FOG flows down a line the line will eventually clog. FOG that does not collect inside drain lines ends up in the sewer system. District sewer line maintenance crews get trouble calls throughout the year due to line blockages caused by excessive amounts of FOG in discharged wastewater. Some of these blockages occur in the customer's sewer line while others cause a more serious problem by obstructing the District's pump stations and sewer lines. Excessive FOG in a wastewater discharge can come from just about any source ranging from a studio apartment to a large industrial facility. Some of the more common sources include restaurants, bars & grills, grocery stores, food processing facilities, automobile service shops, apartments and homes. Even if the FOG does manage to find its way into our wastewater treatment plants (WWTP), it remains a problem substance due to its molecular structure. FOG simply requires much more time, energy, and resources to manage than other, more common organic wastes received at WWTPs. Additionally, FOG is a primary source of sewer odors, whether inside a building or emanating from a sewer line in the street.

FOG is the number 1 cause of sewer back-ups in homes and food service establishments. Even a small amount in drains can cause a serious (and expensive) plumbing blockage, or even worse, an overflow in your home or our community. Managing discharged FOG is expensive. The more it costs the District to maintain the sewer system, the more it eventually costs you, the customer. Please help keep these costs to a minimum. If you have any specific questions or comments regarding the management and disposal of FOG, please contact the District's Pretreatment Coordinator, Brian Asbury, via e-mail at basbury@lakehaven.org or telephone at 253-946-5407.

FATS, OILS AND GREASES - Prevention and Discharge Limits

In our last newsletter, some basic information was given regarding fats, oils, and grease (FOG) and some of the problems it can cause with wastewater. In this article we will focus on some more specific FOG issues.

The District has established a FOG discharge limit of 50 parts per million. This means that for every 61/2 gallons of wastewater discharged it can contain no more than one (1) teaspoon of FOG. This limit was developed primarily for the District's commercial/industrial customers, however it applies to all wastewater discharged to the District. The most effective, and recommended, method of controlling the amount of FOG in wastewater is to simply not let it go down the drain. It is always best to put FOG in the garbage instead of the drain. Wipe-clean all pots, pans, and dishes before washing them in the sink or dishwasher. Store spent FOG (that FOG which cannot be rendered by a professional) by pouring it into an old jar, coffee can, or plastic bag with a zip closure. When full, seal it and tie it up in a plastic bag (a grocery bag works well) and dispose of it with the garbage. Commercial/industrial facilities may choose to utilize some device (grease trap or interceptor) and/or chemical/bacterial/enzymatic additives to pretreat their wastewater for FOG prior to discharge to the sewer system. Proper design for retention time, temperature, and turbulence is just as critical as proper maintenance (routine FOG removal and disposal) for these devices and substances to be effective. Simply installing a properly designed FOG trap or interceptor is not enough - it will need to be routinely pumped out. Use extreme caution when selecting certain "grease-treating" substances. Many of these simply move the FOG down the pipe, avoiding the problem and subjecting the customer to an expensive plumbing blockage and/or a discharge violation. Soap and hot water may help to clear your clogged drain lines, but they do not reduce the FOG in your wastewater. If you have any specific questions or comments regarding the management and disposal of FOG please contact the District's Pretreatment Coordinator, Brian Asbury, via e-mail at basbury@lakehaven.org or telephone at 253-946-5407.