Small and domestic sewage treatment plants used for cleaning of sewage water and that way provide a quality of sewage water which is drain to water courses. For more than half of area of our territory is their role irreplaceable. There appears a question if new technologies or new approaches could be successfully used for reducing the cost of technology and operating expenses of the sewage treatment plant application. For the final decision should not be the most important the project price only but it is as well as important to take in account the quality of sewage water. Therefore I have directed this work on a comparison of methods for the centralized and decentralized cleaning of sewage water produced in small sources of pollution. The optimal solution for cleaning of waste water has to be evaluated based on application of complex conditions relevant for solved source of pollution (agglomeration).