Septic tanks or sludge cisterns are the simplest type of single-unit treatment plant that occurred simultaneously with biological treatment and sedimentation along with anaerobic bacteria. Septic tanks are sheltered caches and usually made with reinforced concrete and prefabricated in small dimensions and with porous polyethylene materials.
The procedure of treat sewage in septic tank After entering the sewage into the septic tank, the sewage system loses its part of the suspended material as it deposits due to the reduction of the hydraulic flow rate next, it goes out. The degree of sewage pollution from the septic membrane will be approximately equivalent to the degree of pollution of the sewage from the initial sedimentation and the percentage of organic load failure and removal of pollutants in septic tanks will not be significant. Sludge deposited on the bottom of the reservoir is digested with anaerobic bacteria so that the storage will need to empty sludge every two years. Septic tank is used for sewage treatment of buildings or residential complexes and it should be noted that today, this method does not have the capacity to deliver sewage to environmental standards.
The history of septic tank According to available reports, in the year 1860 John Morris designed the first septic tank with concrete structures and drained sewage from the houses to the reservoir. In the 1870, Morris with the destruction of the reservoir found that the sewage had a lower solids output than the initial input and was more liquid. In 1881, Morris introduced his invention as "SepticTank" and since 1883, septic tank use in residential homes. After 1940 and World War II, the use of this method was common and customary and offered in cheaper samples. In the 1970s in most cities, septic tanks were designed and installed in different sizes. In 1993, the Natural Resources Conservation Institute was established in Texas and established regulations to create a healthy and sanitary environment for all urban areas using this method.