Criteria of Selection and Proposals Concerning Parameters of Active Sediment for Design of Biological Sewage-treatment Plants.

The results of analyses of numerical productive parameters applied in 31 designs of sewage treatment plants operating under the active treatment methods are considered, including data for 7 completed projects in operation. Proposals of evaluation of these parameters are presented, that are based on many years of design experience and on relevant references. The difficulties in attainment of the assumed design parmeter values in practical applications are explained, and suggestions are made how to increase the professional help by consulting engineers to the constructors and operators of sewage treatment facilities.