Thursday, September 9, 2010

Living With A Septic System

Septic system failure is unpleasant, unsanitary, could be a source of serious disease and cost thousands to tens of thousands of dollars to resolve. Septic failure can result in contamination of the groundwater and nearby drinking water wells or you could find septic tanks sludge backed up into your house or on the surface of your yard. These are routine failures that are easily predicted and prevented. Less predictable is the catastrophic failure of a septic system component.

A typical septic system has four main components: a pipe from the home, a septic tank, a leach field (alternative systems might have drip fields, sand mounds or peat tanks where a leach field is not possible or has failed), and the soil. Microbes in the soil digest or remove most contaminants from wastewater before it eventually reaches groundwater. Many systems also have pumps to move the liquids from the home to the septic tank or from the septic tank to the drain field. There are also Alternative systems that have additional components such as; float switches, pumps, and other electrical or mechanical components including additional treatment tanks.

The septic tank is a buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). It also allows partial decomposition of the solid fecal materials. Compartments and a T-shaped outlet in the septic tank are intended to prevent the sludge and scum from leaving the tank and traveling into the leach field area. Some newer systems have screens and filters to keep solids from entering the leach field. These filters and screens become clogged and need to be cleaned out regularly to prevent septic sludge from backing up into the house.

The basic design of a septic tank will only work if the sludge is not too thick on the bottom and the grease and scum is not too thick on top, and if the flow to the tank is not excessive. If there is too much waste on the bottom of the tank or too much water flowing to the tank, there will not be enough time for the solids and liquids to settle out before the tank starts releasing waste. Water containing large amounts of fecal waste will be released to the drain field. Also, if there is too much grease and scum floating on top, the scum will be released to the leach field. A septic system is not a trash can. Don’t put dental floss, feminine hygiene products, condoms, diapers, cotton swabs, cigarette butts, coffee grounds, cat litter, paper towels, latex paint, pesticides, or other hazardous chemicals into your system. Commercial septic tank additives may assist in the breakdown of fecal waste, but do not eliminate the need for periodic pumping and can be harmful to the system.

Septic tank wastewater flows to the leach field, where it percolates into the soil, which provides final treatment by removing harmful bacteria, viruses, and nutrients. Suitable soil is necessary for successful wastewater treatment. Also, the waste can not contain too much solid material or scum. High quantities of solids in the waste stream will overwhelm the leach field. Initially, nitrogen and fecal bacteria will be released to the groundwater as the soil becomes saturated with solids and scum. Eventually the perforations in the pipes to the leach field through which waste water flows become clogged and the waste backs through the system into your home.

Yet, most homeowners wait until a system fails to take action or even think about maintaining their septic system. The functional lifetime of a traditional septic system is limited. The system is designed so that with proper maintenance it will last 20 to 30 years, under the best conditions. Many other factors besides how much and what you put into your system can cause early failure of a septic system. Pipes blocked by roots, soils saturated by storm water, compacting of the drain field by parking vehicles or heavy objects on the top of the field, improper location, poor original design or poor installation can all lead to major problems.

However, it is more likely that septic systems fail because they are abused, improperly maintained or just old. Remember that the entire functioning of a traditional septic system is based on natural ecological cycles. It needs to be treated kindly and kept in balance. When a system is poorly maintained and not pumped out on a regular basis, sludge (solid material) builds up inside the septic tank, and then flows into the leach (absorption) field, clogging it beyond repair. Excessive load from toilets and garbage disposal, putting grease, coffee grinds, kitty litter or any kind of trash down the drain will effectively decrease the size of the tank and the time that the solids have to settle out. This will decrease the life of and potentially overload the system. Even with proper use and maintenance the system will wear out. A garbage disposal adds solids and increases the biological load on a septic system.

If the amount of wastewater entering the system is more than the system can handle, then wastewater either backs up into the house or the yard or both. Doing load after load of laundry on a single day could overwhelm the system. A leaking toilet or sink will overwhelm the system. If you have a septic system you cannot ignore even small leaks. Emptying a hot tub or draining a water bed down a drain into your septic system stirs the solids in the tank and pushes them out into the leach field, causing it to clog and fail. A sump pump should never be pumped to a drain. Some freshwater purification systems, including reverse osmosis systems and water softeners, unnecessarily pump large quantities of water into the septic system. This can contribute a hundred gallons of water or more to the septic tank each day, causing agitation of solids and excess flow to the leach field.

To prevent problems, only put reasonable amounts of grey water, human waste and a limited amount of TP into your system and have your septic system inspected and pumped regularly. In the past decade EPA has shortened the recommended time between tank pump outs. EPA is now recommending pumping the tank every three years. Many towns and counties have no requirements for pump outs or use the older every five year recommendation. Remember, the most likely time for your septic system to back up is when you have a lot of guests at your home using the bathrooms. This is one holiday “gift” you might want to avoid.

1 comment: