analysis of the operational deficiencies originating in design at wastewater treatment plants: a case study of the islamic republic of iran

considerable investments have been made in establishing wastewater treatment plants (wwtps). however, evaluation of the performance of plants during recent years, when more wwtps have become operational, shows that effluent quality criteria were not met in many instances. preliminary assessment of the operational problems of wwtps in iran disclosed that numerous factors affect this issue of effluent quality. one reason is the lack of planning knowledge among the local consulting engineering companies, which causes design-related deficiencies. lack of national standards as well as of practical design manuals are also significant factors. in this study, the effects of the design-related deficiencies on operational practices are investigated in 20 wwtps around iran. this is followed by the implementation of solutions in real models that match the most recent innovations in this regard. consistent methods are then discussed for correcting these deficiencies. it was found that 68% of the operational deficiencies arise from design deficiencies. these are, accordingly, considered in the scope of the solutions presented in this work. the distinctive solutions presented in this study prevent the repetition of the same defects in new designs. scientific methods for rectifying the detected deficiencies are developed in this study. the results are aimed at supporting experts who undertake the role of rehabilitating wwtps in the country, through the correction of various deficiencies, so that the final goal of conserving the environment is met. the findings are compared with those of some related national and international works for the purposes of further clarification.