Septic Tank and Standard System in Onsite Wastewater Treatment
How does an onsite wastewater treatment system work?
Sewage from the home first goes into a septic tank - a large, watertight chamber made of concrete, fiberglass, or plastic with baffles or tees at the inlet, and outlets. Household waste enters the septic tank where heavy solids settle out to form a layer of sludge on the bottom. Grease and light solids float to the top forming a layer of scum. Inside the septic tank, anaerobic (oxygen-lacking) bacteria partially break down the sewage. The liquid that remains after the solids settle out of the sewage in the septic tank is called effluent.
Sewage from the home first goes into a septic tank - a large, watertight chamber made of concrete, fiberglass, or plastic with baffles or tees at the inlet, and outlets. Household waste enters the septic tank where heavy solids settle out to form a layer of sludge on the bottom. Grease and light solids float to the top forming a layer of scum. Inside the septic tank, anaerobic (oxygen-lacking) bacteria partially break down the sewage. The liquid that remains after the solids settle out of the sewage in the septic tank is called effluent.
After leaving the septic tank, effluent may need to flow through an effluent filter to ensure enough solids are removed form the sewage. The effluent may flow to a distribution device or pump tank before it enters the soil absorption (lateral) field. The soil absorption field is a network of trenches dug into the soil. In these trenches are various types of structures that help convey the effluent down the trench and allow it to be absorbed into the soil. The absorption field is where filtration and aerobic (oxygen-using) bacteria in the soil remove most of the remaining impurities (pathogens and chemicals) before the wastewater returns to groundwater.
Pump to Gravity Flow Absorption Field
How does a pump to gravity septic system work?
Sewage from the home first goes into a septic tank - a large watertight chamber made of concrete, fiberglass, or plastic with baffles or tees at the inlet and outlet. Inside the septic tank, anaerobic (oxygen-lacking) bacteria partially break down sewage. There is always a portion of the solids which bacteria cannot digest, and these remain in the tank as sludge and scum.
After leaving the septic tank, effluent (the liquid from the sewage) enters into a pump chamber, which is then pumped to the absorption field via a manifold. The soil absorption field is a network of pipes laid in trenches dug into soil and surrounded by gravel. Perforations in the pipe allow the sewage to drain through the gravel into the soil, where the majority of the actual treatment occurs. The absorption field is where filtration and aerobic (oxygen-using) bacteria remove the remaining impurities (germs and some chemicals) before the wastewater returns to the groundwater.
Sewage from the home first goes into a septic tank - a large watertight chamber made of concrete, fiberglass, or plastic with baffles or tees at the inlet and outlet. Inside the septic tank, anaerobic (oxygen-lacking) bacteria partially break down sewage. There is always a portion of the solids which bacteria cannot digest, and these remain in the tank as sludge and scum.
After leaving the septic tank, effluent (the liquid from the sewage) enters into a pump chamber, which is then pumped to the absorption field via a manifold. The soil absorption field is a network of pipes laid in trenches dug into soil and surrounded by gravel. Perforations in the pipe allow the sewage to drain through the gravel into the soil, where the majority of the actual treatment occurs. The absorption field is where filtration and aerobic (oxygen-using) bacteria remove the remaining impurities (germs and some chemicals) before the wastewater returns to the groundwater.
Why maintain your system?
The first and most important reason to maintain your system is to protect the health of your family, your community, and the environment. Untreated wastewater from a failing system can contaminate nearby wells, groundwater, and drinking water sources. Once wastewater has polluted the water table, it can become extremely difficult and costly to manage and treat, sometimes at the owners expense.
Significant health risks include hepatitis A, diarrhea, salmonella, giardiasis, tetanus, hookworms, cholera, dysentery, typhoid fever, and staphylococcal infections. Waste water can pollute local water ways with nitrogen and phosphorus.
The second reason is money. Failing systems are expensive to repair and replace, and poor maintenance is a common cause of premature system failure. Routine preventative maintenance costs very little compared to a system replacement. For example a system inspection and maintenance, including pumping the tanks, costs from $150-$300. In contrast, replacing a failing system with a new one typically costs from $4,500 to $30,000, assuming you have enough property to install the replacement system. In addition, property values drop when a system fails.
The third reason is lack of alternatives. A lagoon system was specified for your building location because of some limiting factor(s) in the soil or space constraints. You need to care for the system to keep it operating because there may not be any other legal and healthy ways to handle sewage at your location.
The first and most important reason to maintain your system is to protect the health of your family, your community, and the environment. Untreated wastewater from a failing system can contaminate nearby wells, groundwater, and drinking water sources. Once wastewater has polluted the water table, it can become extremely difficult and costly to manage and treat, sometimes at the owners expense.
Significant health risks include hepatitis A, diarrhea, salmonella, giardiasis, tetanus, hookworms, cholera, dysentery, typhoid fever, and staphylococcal infections. Waste water can pollute local water ways with nitrogen and phosphorus.
The second reason is money. Failing systems are expensive to repair and replace, and poor maintenance is a common cause of premature system failure. Routine preventative maintenance costs very little compared to a system replacement. For example a system inspection and maintenance, including pumping the tanks, costs from $150-$300. In contrast, replacing a failing system with a new one typically costs from $4,500 to $30,000, assuming you have enough property to install the replacement system. In addition, property values drop when a system fails.
The third reason is lack of alternatives. A lagoon system was specified for your building location because of some limiting factor(s) in the soil or space constraints. You need to care for the system to keep it operating because there may not be any other legal and healthy ways to handle sewage at your location.
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DO's of Maintaining your System
Do obtain necessary permits from the appropriate local agency before doing any construction or repairs.
Do use professional certified installers when needed. Do keep your septic tank accessible for pumping and adjustment. Install risers if necessary. The covers should be locked or of sufficient weight to prevent a child from lifting them. Do have your septic tank inspected annually and tank pumped out every 2-5 years by a professional contractor. Do keep a detailed record of repairs, pumpings, inspections, permits issued and other maintenance activities. Do conserve water to avoid overloading the system. Repair dripping faucets and leaking toilets, avoid long showers and run washing machines and dishwashers only when full. Use water-saving features in faucets, shower heads and toilets. Do divert other sources of water, like roof drains and hillside runoff away from the lagoon system. Use curtain drains, terraces, downspout extensions, retaining walls, etc. to divert water. Do take leftover hazardous household chemicals to an approved hazardous waste collection center for disposal. Use bleach, disinfectants and drain and toilet bowl cleaners sparingly and in accordance with product labels. |
Don'ts of Maintaining your System
Don't go down in a septic tank for any reason. Toxic gases in the tank can be explosive and cause asphyxiation.
Don't allow anyone to drive or park over any part of the system. Don't allow the overflow from the lagoon to leave your property, event during wet weather. A grass cover will not only prevent erosion, but will help dispose of excess water. Don't plant trees or shrubbery near the lagoon. This could cause shading, sludge buildup and increased odor levels. Decaying vegetation can lead to voids in the lagoon berm and promote berm leakage. Don't make or allow repairs to your lagoon system without obtaining the necessary permits. Don't pour into drains any grease, cooking fats, chemical drain openers, paint, varnishes, solvents, fuels, waste oil, photographic solutions, pesticides, pharmaceuticals or other organic chemicals. These materials can upset the bacterial action in the septic tank or lagoon and pollute groundwater. Don't use your toilet for trash as a trash can. Keep out coffee grounds, bones, cigarette butts, disposable diapers, feminine hygiene products, paper towels, facial tissues and other materials that decompose very slowly. Don't add enzyme or yeast additives to the septic tank or lagoon in hopes of improving bacterial action. None have been proven beneficial and some actually cause damage to soil and vegetation and may pollute groundwater. |