The secondary stage of treatment removes about 85 percent of the organic matter in sewage by making use of the bacteria in it. The principal secondary treatment techniques used in secondary treatment are the trickling filter and the activated sludge process.,
The purpose of secondary treatment is to remove the suspended solids that did not settle out in the primary tanks and the dissolved BOD that is unaffected by physical treatment. It is called biological treatment because it involves the use of microbes.
Secondary treatment of sewage is called biological treatment because it involves living organisms such as aerobic or anaerobic microbes to digest the organic waste. [ 1] In this process, the primary effluent is first passed into an aeration tank where vigorous growth of aerobic microbes (flocs) takes place.
Secondary treatment removes the dissolved organic matter by the use of biological agents and hence, known as biological treatment. This is achieved by microbes which can consume and degrade the organic matter converting it to carbon dioxide, water, and energy for their own growth and reproduction.
Secondary treatment is the second step in most waste treatment systems during which bacteria consume the organic parts of the wastes. This is accomplished by bringing the sewage, bacteria and oxygen together in trickling filters or within an activated sludge process.Mar 13, 2003
Secondary sewage treatment is mainly a biological process. In secondary treatment primary effluent is passed into large aeration tanks, where it is constantly agitated mechanically and air is pumped into it. ... These microbes consume the major part of the organic matter in the effluent while growing.
Secondary treatment is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. ... During secondary treatment, biological processes are used to remove dissolved and suspended organic matter measured as biochemical oxygen demand (BOD).
Secondary treatment involves the removal of biodegradable organic matter (BOD) and suspended solids (TSS) through the processes of aeration and filtration. Secondary treatment is typically characterized as producing a treated wastewater effluent with a BOD of 25 mg/L or less and TSS of 30 mg/L or less.