Top 10 Septic System Design
Top 10 Septic System Design
Septic tanks with drain field are in use in 25% of all homes in rural America. When public sewer line hookups are not available within a reasonable proximity of our home, we have limited choices with reference to house hold wastewater and how to dispose of it. Standard concrete septic tank system with a gravity fed drain field designed schedule 40 PVC and a gravel bed are the easiest, tried and proven method available. These systems have been around the longest and if treated properly, they will give the homeowner many years of practically maintenance free service.
However, other types of wastewater systems available could supply temporary and permanent on sight wastewater relief. These systems are typically large, bulky and require frequent regular maintenance. With the advancement of research and technology in the industry, many new and improved residential onsite waste water systems are available and new designs are coming on to the market every day. Depending on the municipality, you live in and your local code, will determine what type of system you may use.
Drip Irrigation and Sprinkler Septic Systems are available in most states. This system is somewhat more involved than most homeowners are willing to take part. The wastewater is channeled through a pretreatment system or an aerobic septic tank. The effluent transfers to a free access buried sand filter. In the final step, the effluent is channeled through an additional disc filter system with a backwashing system that returns to the first tank for reprocessing. The effluent or leachate, is then distributed near the top of the surface or grade level through1/2 inch small diameter plastic piping. This system will usually use flow controllers to meter the effluent output. This system should only be utilized in a non-food planed operation environment due to the threat of coli form bacterial contamination. As I said earlier, some systems can be very involved and the Drip Irrigation and Sprinkler system in any form requires regular monitoring and maintenance.
Sand Mound Septic System or sometimes referred to as “Turkey Mound Septic Systems” are becoming more and more common in areas where the soil does not perk (absorb water) or in areas where there is a very high water table. The mound system allows for the use of land that would otherwise not be suitable for the construction of homes using a below ground system. Mound systems may be utilized in most areas of the country. Sand mound systems are a great advantage and designed very much like a standard septic tank and gravity fed drain field with the exception of the pump lift station or sometimes referred to as the dosing chamber. The wastewater is drained or pumped from the house into a standard septic tank where the digestion process of the solid material take place. When the digested effluent rises to a certain level, it will spill over the baffle area into the dosing chamber where the dosing pump will pump the effluent up into the absorption area of the above ground sand mound. Mound systems are typically more expensive to install than a standard gravity fed system but less expensive than a Drip Irrigation and Sprinkler Septic System.
Cesspits or Cesspool Septic System is basically a cistern with a cover or tank that consist of a hole in the ground with a depth ranging from 6 to 20 feet. They are considered the oldest types of residential wastewater disposal systems dating back to the1500’s and even earlier. They are constructed typically of stone, rock and in modern day concrete. There are several different variations of these systems. Some systems have two tanks consisting of the first tank being a holding tank and the second tank being the leaching tank where the digested effluent will seep into the ground. Cesspits and Cesspools type septic systems are more common in the northeastern parts of the U.S. These types of systems are typically out dated and are now being replaced with modern onsite wastewater systems.
Dry Well is an underground man made well that is typically filled with gravel, stone or rock and rubble. Dry wells’ are used in several applications ranging from storm water runoff to grey water generated by homeowners. The system works off of gravity and is fed by pipes, drain tile or drain ditches running from the water source. Commercial dry wells, typically are regulated and monitored by the local municipality in order to protect local drinking water supplies. Aerobic Septic Treatment Systems typically are constructed in the same way a conventional concrete gravity fed system is designed. The aerobic systems designed is achieved by adding an air pump creating oxygen in the second stage if the septic tank. The fine bubbles created by the oxygen generation increase the bacteria in order to increase digestion process for the breaking down solids into effluent.
Standard gravity fed systems can be converted to aerobic systems with a simple conversion kit by adding an oxygen pump to the existing system. These aeration systems are effective in maintaining septic tanks and their drain fields.
Grey Water System is referred to as any water that is produced by a home with the exception of toilet water. In some areas of the country, grey water may be recycled and used to irrigate landscaping and gardens. Grey water systems benefit us by lessening the strain on septic tank drain fields and local sewer treatment plants. Grey water systems may be illegal in your area , so check with your local municipality or code enforcement officer for details.
Septic System Holding Tanks In the case where a cottage or lake house and the lot is not large enough or practical to facilitate a normal septic tank and drain field, a temporary holding system may be installed. This type of system is usually simple in construction, leak proof plastic or steel tank. This type of system is costly to maintain would require frequent pumping. The system would require the approval of the local municipality as well as a pumping log.
Non-Waterborne Systems are used in a single-family residence, typically used where water is scares and not economical to flush down the toilet. These systems provide satisfactory sanitary conditions. They consist of sanitary pit, composting toilets and incinerating toilets. The systems are restricted to solid waste matter only. Non-Waterborne Systems require monitoring and require a high level of maintenance.
Lagoon Ponds (Oxidation Ponds) may also be described as sewage or wastewater stabilization ponds. They are used typically as a secondary treatment for residential septic tank effluent. This system uses bacteria to digest organic matter and will help in the growth of algae. The algae will assist in the further decomposition of solid matter with the release of oxygen.
Most lagoon ponds require less than 10 feet of depth in order to stimulate algae growth. Lagoon ponds used to treat residential sewage are limited to the warmer temperature regions. Algae and bacteria flourish in warmer climates creating the perfect digestion environment. Lagoons are designed and constructed in most types of soils with the exception of heavy clay and sandy clay loam. The dimensions are typically 400sq. feet in surface and 5 ft. in depth for a three-bedroom house. Larger homes will require larger ponds with an increase of 150 sq feet per bedroom. The design will change depending on the local municipality code.
By: Bradley Skierkowski