Treatment of Coal Industry Effluents

Large amount of suspended solids and high chemical oxygen demand are present in the coal industry effluents, which on contamination with water creates serious problems to the existing aquatic life and in adjacent localities. The effluents discharged by thermal power plants (TPP) require treatment before they are discharged into the freshwater streams. Effluents from TPPs include thermal discharges, wastewater effluents, and sanitary wastewater. The process of wastewater treatment is long and fluctuates greatly about projects in the construction. The stability of treatment effect needs to be validated. For the domestic wastewater, the treatment process mainly includes adjustment, deoiling, sedimentation, and flotation. Main treatment process has been formed by sophisticated equipment. The removal of emulsified oil, dissolved oil, and subdivision oil requires addition of drugs and even multistage flotation. There are many biochemical treatment processes. Conventional activated sludge treatment processes include oxidation ditch, sequencing batch reactor, air oxidation, common activated sludge process, and membrane bioreactor process.