efficiency of sbr process with a six sequence aerobic-anaerobic cycle for phosphorus and organic material removal from municipal wastewater

Background: various chemical, physical and biologic treatment methods are being used to remove nitrogen and phosphorus from wastewater. sequencing batch reactor (sbr) is a modified activated sludge process that removes phosphorus and organic material from sanitary wastewater, biologically.methods: this study was conducted in 2016.the performance of an aerobic-anaerobic sbr pilot device, located at ahwaz west wastewater treatment plant, ahwaz, southern iran in phosphorus and organic material removal was evaluated to determine the effect of the aerobic-anaerobic step time on the efficiency of nitrogen and phosphorus removal, the effect of changing the sequence of steps and the effect of time ratio on phosphorus removal efficiency. a reactor of 8 l was used. influent contained 397 and 10.7 mg/l cod and phosphorus, respectively. the pilot plant started with a 24 h cycle including four cycles of 6 h, as follows: 1- loading (15 min), 2-anaerobic (2 h)-aerobic (2 h), 3- settling (1 h), idleness (30 min) and 5- decant (15 min). results: after reaching steady conditions (6 months), removal percentages of phosphorus, bod5, cod, and tss in the sbr over a period of 6 months was 79%, 86%, 89% and 83%, respectively.conclusion: result of this study can be used for designing and optimum operation of sequencing batch reactors.