Performance of Attached Growth Biological Reactor in Wastewater Treatment in Small Communities

Background & objectives:The attached growth process is an aerobic method for wastewater treatment where microorganisms grow on the surface of a substrate.In this study, a small-scale attached growth reactor was used for wastewater treatment for eight weeks in rural and small communities.Methods: The average operational parameters of HRT, DO, MLSS, and MLVSS were measured in the pilot-scale reactor.The reactor's ability to remove suspended solids, organic materials such as BOD5, COD, and nutrients like TP, TKN, 4NH-N, as well as coliforms, was also analyzed.Coliform tests were conducted using the MPN method and dilution, BOD5 tests were performed with a BOD measuring device, and COD tests were carried out using the COD Set-Ups COD VARIO method and purchased kits. Results:The average removal efficiency for BOD5, COD, TP, TKN, NH4-N, TSS, fecal coliforms, and total coliforms was 73.1%, 82.5%, 48.9%, 58%, 82%, 92.8%, 85%, and 81%, respectively. Conclusion:The results of this study indicated that the stability of the microbial biomass present in the biofilm is observed after several weeks of system operation, and the attached growth system effectively reduces solids and organic compounds during its various stages.Additionally, acceptable results regarding total and fecal coliforms were obtained in the absence of any disinfection, indicating that the attached growth system can be a suitable option for wastewater treatment in small communities.