K-State Scientist: Certain Items, Chemicals Can Damage Septic Systems

K-State Scientist: Certain Items, Chemicals Can Damage Septic Systems

MANHATTAN, Kan. – Ah, the allure of country life. Wide-open spaces and the appeal of less traffic have inspired many a family to move beyond the city limits. And if you live in the country, chances are you have an onsite wastewater treatment system.

“When living in the country, septic systems or other onsite wastewater treatment systems are the norm,” said Kansas State University scientist DeAnn Presley. “In 2007, the EPA reported that an estimated 20 percent of total U.S. housing units were served by septic systems. Of these, 50 percent were in rural areas, 47 percent were in suburbs, and 3 percent were found in central cities.”

Most of these systems consist of a septic tank and some type of soil treatment area, said Presley, who is a soil management specialist with K-State Research and Extension. The soil treatment area typically contains gravity laterals or a drip field.

“Whatever soil treatment is used, consideration should be given to the fact that anything placed down the drain potentially could be detrimental to the function or components of the septic system or to groundwater quality,” she said.

For a homeowner to understand why certain items are a problem, it’s helpful to explain how the systems work. Three layers develop in the tank. The bottom layer is the solids (sludge), which settle out in the tank. The middle is partially clarified water, or effluent. The upper layer consists of floating scum, including fats, oils and greases (FOG). Only the effluent from the middle layer should enter the soil absorption field because solids and scum eventually plug the oil pores and lead to slower rates of absorption and potential system failure.

There are two categories of items that should not be put into a septic system: “Cloggers” and “Killers,” Presley said.

* Cloggers include diapers, cat litter, cigarette butts, baby wipes, coffee grounds, grease and feminine hygiene products, all of which can contribute to a buildup in either the sludge or FOG layer. Therefore, they should never be flushed or put down a drain. It is not a good idea to put large quantities of food waste at one time into an onsite wastewater treatment system as this can cause the sludge and/or FOG layer to build up more quickly, and adds more biochemical oxygen demand on the beneficial microbes in the onsite wastewater treatment system.

* Killers include household chemicals, gasoline, oil, paint, pesticides, antifreeze and unused prescription medications. Remember that onsite wastewater treatment systems treat wastewater—they do not dispose of water. If strong chemicals are added to the system, they might temporarily kill off beneficial microorganisms, resulting in little or no treatment of the wastewater. Also, many of these chemicals are toxic to other biological organisms, and could damage the quality of the area’s groundwater. Whenever possible, use local household hazardous waste programs to dispose of unused chemicals, so that they might be properly recycled by professionals. Return unused prescription medications to pharmacies, or dispose of them in the trash. If you’re worried about children, animals or thieves getting medications out of the trash, you could put them inside another container and tape it tightly, or combine it with coffee grounds.

K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by: Mary Lou Peter
mlpeter@ksu.edu
K-State Research & Extension News
DeAnn Presley – 785-532-1218 or deann@ksu.edu.