In general, the activated sludge process is a continuous or semi continuous (fill and draw) aerobic method for biological wastewater treatment, including carbonaceous oxidation and nitrification. This process is based on the aeration of wastewater with flocculating biological growth, followed by separation of treated wastewater from this growth. Part of this growth is then wasted, and the remainder is returned to the system. Usually, the separation of the growth from the treated wastewater is performed by settling (gravity separation) but it may also be done by flotation and other methods. SHIVAM also deals with modification of Activated sludge like extended aeration etc.

• oxidizing carbonaceous matter: biological matter.
• oxidizing nitrogeneous matter: mainly ammonium and nitrogen in biological materials.
• removing phosphate.
• driving off entrained gases carbon dioxide, ammonia, nitrogen, etc.
• generating a biological floc that is easy to settle.
• generating a liquor low in dissolved or suspended material.