Tuesday, September 22, 2015

Septic Systems and Water Quality

September 21-25  is the U.S. Environmental Protection Agency’s Third Annual SepticSmart Week.

During SepticSmart Week, EPA seeks to inform homeowners on proper septic system care and maintenance, assist local agencies in promoting homeowner education and awareness, and educate local decision makers about the infrastructure options available to improve and sustain their communities.

The Michigan Department of Environmental Quality (MDEQ) quotes a Rouge River Wet Weather Demonstration Project document to explain septic systems: (excerpts)

Septic systems are waste water treatment systems that use septic tanks and drainfields to dispose of sewage. They are typically used in rural or large lot settings where a sanitary sewer is not available...

A septic system usually is made up of a septic tank and a drain field. The septic tank is usually made of reinforced concrete, is buried and watertight. This tank receives untreated household waste. The drain field consists of a series of perforated pipes (pipes with holes in them), which distribute the liquid from the septic tank to the surrounding soil.

Although even the best designed and installed system will eventually fail, proper maintenance will ensure a longer lasting waste disposal system…

When waste enters the tank, bacteria begin to break down the solid materials. This break down reduces solids, but also leaves a residue behind in the tank. As time passes, this residue builds up, and must be removed to prevent it from entering the drainfield and clogging the system. The center liquid layer flows slowly from the tank into the drainage field. Perforated pipes allow the liquid to be equally distributed in a gravel-filled disposal field. Once the liquid reaches the disposal field, it soaks into the soil. The soil then acts as the final filter for treatment of waste received from the septic system.

Onsite sewage disposal (septic) systems are common in southeast Michigan. In Oakland County, for example, there are more than 80,000 such systems.

According to the Oakland County Health Division, “...proper disposal of solid, liquid and sewage wastes is crucial to prevent contamination to the land and the groundwater below. The use of sewers and municipal sewage treatment plants is limited to areas where infrastructure exists. On-site sewage disposal is the only viable alternative in areas not serviced by municipal sewers.”

The Health Division’s Environmental Health Services Unit issues “...permits and conducts construction and final inspections for the installation of residential and non residential on-site sewage disposal systems…”


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