The  concept  of  effluent  treatment,  by  means, of  a collective  effort,  has  assumed  reasonable  gravity  by being  especially purposeful  for  cluster  of  small  scale  industrial  units. Common effluent treatment plant (CETP) not only help the industries in easier control  of  pollution,  but  also act as a step towards cleaner environment and service to the society at large. Small scale industries,  by  their  very  nature  of  job  cannot  benefit  much  from economies of scale and therefore the burden of installing pollution- control equipment, falls heavy on them. Realising this practical problem, under the policy statement for abatement of pollution the Govt. felt to extend the scheme for promoting combined facilities for treatment of effluent and management of solid waste  for  clusters  of  small  scale industria l units  and  also to  provide  technical  support  to  them. Accordingly, Ministry of Environment & Forests, Govt. of  India, had  instructed  various  State Pollution Control Boards, to examine the possibilities of establishing CETPs in various Industrial estates in the respective states.

The  concerted  approach  of  joint  or common  effluent  treatment  provisions has many advantages. Wastewater of individual industries  often  contain  significant  concentration  of  pollutants;  and  to  reduce them by individual treatment upto the desired concentration, become techno-economically difficult The combined treatment provides a better and economical option because of the equalization and neutralization taking place in the CETP.

Other  important  issues for the  merit of common treatment include, scarcity of land at the industry's level and a comparatively easier availability of professional and trained staff for the operation of CETP, which  can otherwise be difficult, at the individual industry  level. For  the  regulatory  authorities  also, common treatment  facility offers a comparatively easier means of ensuring compliance of stipulated norms. The handling and disposal of solid- waste also becomes increasingly easier as the infrastructure is  created  in  the project  itself. The concept of common  treatment,  based on  feasibility, should  be part of the new industrial estates  as  essential component of  infrastructure,  In fact, the  location  of  industries  should  always  be such  that  units  with compatible nature of activity are located in a cluster which in-turn can facilitate in providing common treatment .