STP Plant is the process of removing contaminants from wastewater, primarily from household sewage. It includes physical, chemical, and biological processes to remove these contaminants and produce environmentally safe treated wastewater (or treated effluent). A by-product of STP Plant is usually a semi-solid waste or slurry, called sewage sludge, that has to undergo further treatment before being suitable for disposal or land application. STP Plant may also be referred to as wastewater treatment, although the latter is a broader term which can also be applied to purely industrial wastewater. The STP Plant process is similar to the way that a Septic Tank works but mechanical components provide a process to help break down solids to produce a cleaner, more environmentally friendly effluent. Now a days the STP Plant became statutory requirement of all the State Pollution Control Boards, everybody, whether Hotelier or Industrialist were looking for economical, easy to install and operate compact type Sewage Treatment Plant.