The main objective of secondary treatment: To remove most of the fine suspended and dissolved degradable organic matter that remains after primary treatment, so that the effluent may be rendered suitable for discharge. Conventional secondary treatment can reduce the BOD's

Is defined as a ‘Suspension’ of microorganisms, both living and dead’ in a wastewater. The microorganisms are active by an input of air (oxygen) thus known as activated-sludge. Activate-sludge is that sludge which settle down in a secondary sedimentation tank after the sewage has been freely aerated and agitated for a certain time in an Aeration tank. It contains

The activated sludge form the underflow of the final setting tanks should be returned to the inlet of the aeration tanks at a rote sufficient to maintain the MLSS concentration at the design value. Excess activated sludge withdrawal system and subsequent treatment and disposal of waste sludge. Since the whole process takes place in a liquid medium the hydraulic

Microorganisms are significant in water and wastewater because of their roles in different transmission and they are the primary agents of biological treatment. They are the most divers group of living organisms on earth and occupy important place in the ecosystem. Are called OMNIPRESENT. Classification of bacteria based on Oxygen requirements (ORP)

A. Atterberg defined the boundaries of four states in terms of "limits". A fine-gained soil can exist in any of several states; which state depends on the amount of water in the soil system. When water is added to a dry soil, each particle is covered with a film of adsorbed water. If the addition of water is continued, the thickness of the water film on a particle increases.