Performance of sequencing batch reactor (SBR) of treated tofu wastewater: Variation of contact time and activated sludge sources

One of the wastewater treatment system that is able to reduce levels of contamination are industrial wastewater using Sequencing Batch Reactor (SBR). Important in the early stages of SBR is filling phase (filling) consisting of seeding and acclimatization period. In the seeding and acclimatization period, the reactor will be filled with activated sludge and wastewater aeration process during the next study period. This research was conducted to find out sources and the best contact time of the activated sludge in lowering the concentration of COD and TSS from wastewater of tofu industry. Activated sludge which will be used is sourced from slaughter house, gutters of tofu industry, and polluted rivers. The variation of contact time which will be used is day 0; 1; 3; 5; 9 and 13. The results showed that the activated sludge are sourced from a polluted river sludge with the best percent COD reduction of 81% and TSS by 94% at day 13.