The parboiled rice effluent has high phosphorus concentration. A sequential batch reactor (SBR) was fed with a UASB reactor effluent and operated with three anaerobic and aerobic phases and solids retention time (SRT) of 25 d, 15 d, 10 d and 5 d, and reaction time (tR) of 1 d, 2 d and 3 d, with and without acetic acid (HOAc) addition. The reactor operated with 5 d of SRT and two phases treating equalization tank effluent. The removal efficiency was calculated by the relation between phosphorus suspended wasted mass and feed mass. The biggest removal potential, 46.14 mg, was operated with HOAc addition and one anaerobic and aerobic phase. The biggest possibility of efficiency increase by biomass waste was obtained with tR=1 d. The system operating with smaller SRT achieves higher removal efficiencies. The removal capacity is better utilized with five days of SRT. The highest efficiency (E=17.82%) was obtained by treating the UASB reactor effluent with two phases, five days of SRT, without HOAc addition.
parboiled rice; nutrients; reactor UASB
