Domestic Wastewater Treatment

Domestic wastewater is typically divided into two varieties: gray water and blackwater. The liquid waste from bathing, showering, washing dishes and clothes is called gray water; while, the water waste consisting of fecal matter and urine is called blackwater.

Gray water (also known as greywater) or sullage is considered fit for watering the plants and for use in toilet flushes. If it does not have some specifically known harmful chemicals, it may be used for the above-mentioned purposes, without considerably worry.

Domestic wastewater management is usually divided into three stages i.e. main, secondary and tertiary. These are briefly described below:
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Primary Stage: The principal purpose of the primary stage is to separate the solid and liquid matter of the sewage, so as to ease the procedure of treatment. This is required as you’ll find different, certain ways to treat solid and liquid wastes. Sedimentation is used for the purpose of separation here. Sewage is kept in big tanks designed to carry out sedimentation. These tanks are huge enough for sludge to settle down at the bottom and oil, grease and other floating material to rise up to the top, from where it can be easily skimmed off.

Secondary Stage: The secondary stage is meant for the removal of dissolved biological matter from the sewage water. This job is best done by indigenous water-borne microorganisms. The solid wastes obtained by this way, is either subjected to special treatments to create it fit for reuse or is disposed of. Secondary treatment systems are categorized as follows:

Fixed Film System: Fixed film program includes trickling filter and rotating biological contactor. These are provided with growth media to facilitate the growth of biomass and the sewage water passes via it.

Domestic wastewater treatment is focused generally on treating blackwater. Blackwater is the best medium for the growth of pathogenic bacteria. Consequently, it really is incredibly essential to treat it prior to reuse or to be discharged into rivers and lakes. Sewage, a further term for blackwater, is also called brown water or foul water.

You will discover local, federal and state standards for sewage collection and management. Sewage might be treated in a local wastewater treatment plant. The local sewage treatment plants have biofilters, septic tanks or an aerobic treatment system. If this facility isn’t obtainable, it’s carried away by sewers to the master plant run by the municipal authorities of the location concerned. Each and every city has a well-defined pipe infrastructure for this purpose.