University Of Tehran Press Pollution 2383-451X 4 4 2018 10 01 Upgrading the Performance of Urban Wastewater Facultative Ponds by changing to Attached Baffled Process 725 735 68063 10.22059/poll.2018.249638.376 EN Hossein Sasani Graduate Faculty of Environment, University of Tehran, P.O.Box 14155-6135, Tehran, Iran Naser Mehrdadi Graduate Faculty of Environment, University of Tehran, P.O.Box 14155-6135, Tehran, Iran Behnoush Aminzadeh Graduate Faculty of Environment, University of Tehran, P.O.Box 14155-6135, Tehran, Iran Afshin Takdastan Department of Environmental Health, School of public health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Journal Article 2018 01 06 This study aims at evaluating the improved facultative ponds performance in pilot scale. Wastewater has been collected from primary settling basins of Ahvaz wastewater treatment plant. Treatment efficacy of the four systems (three systems in parallel with a control system) has been evaluated over a period of 12 months at various hydraulic retention times (HRT) and organic loading rates (OLR). There has been no baffle and no attached growth media (AGM) in the control system (S₀), while other three systems (S₂, S₃, and S₄) have been equipped with different numbers of baffles and AGM packages, containing the mineral shells. Results show that efficiency of BOD₅ removal for S₀, S₂, S₃, and S₄ are 53.4%, 60.8%, 64.7%, and 67.6%, respectively, while for COD these rates alter to 28.1%, 37.7%, 45.8%, and 50.1 % and of coliform to 66.7%, 76.6%, 80.7%, and 83.4%. Filtered BOD₅ in the effluent of S₀, S₂, S₃, and S₄ is 32.5, 27.6, 24.6, and 22.3 mg/l, respectively and 60.2, 52.1, 47, and 44.3 mg/l for TSS. Also the 10-day HRT has been optimum among applied HRTs. As such, attached growth-baffled ponds function better than conventional ones, making the technique, examined in the present paper a low-cost process to establish new wastewater treatment plants or upgrading the existent WSPs, especially in case of warm areas of southwestern Iran. https://jpoll.ut.ac.ir/article_68063_e361e4554b9fb3f8c148e4a3dff048c8.pdf