Abstract:
The research aimed to study the efficiency of Sequencing Batch Reactor system by using yeaststrain (Candida utilis: TISTR No. 5001) to treat the synthetic wastewater with various pH of 5, 6, 7,8 under HRT of 10 days. And then, the optimal pH of the condition was selected for observation ofthe optimal HRT value (10, 7, 5, 3 days). And the optimal condition of the SBR system was testedwith cool storage factory wastewater.The results showed that the synthetic wastewater with COD concentration of 2,000 mg/l weretreated by SBR system with yeast strain, yeast strain & bio-sludge, and bio-sludge at the CODremoval efficiency of 97.7, 97.6, 97.5, 96.7 % and 98.2, 98.1, 97.8, 97.8 % and 97.8, 98.3, 98.4,98.4 %, respectively. The effluent COD of the systems were 48.7, 49.8, 53, 71.6 mg/l and 40.4,40.8, 45.3, 45.2 mg/l and 48, 36.4, 33.7, 34.3 mg/l, respectively. However, the highest CODremoval efficiency of 97.7% and the effluent COD of 48.7 mg/l were shown in the SBR system withyeast strain with initial pH of 5. And the lowest COD removal efficiency of 96.7% and the effluentCOD of 71.6 mg/l were shown in the SBR system with yeast strain with initial pH of 8.For the determination of HRT under pH of 5, the SBR system with yeast strain, yeast strain & biosludge,and bio-sludge, showed the COD removal efficiency of 97.8, 97, 97, 97.2% and 98.2, 97.4,97.2, 97.2% and 97.8, 97.5, 97.2, 97.1% respectively. The effluent COD of the systems were 48.7,61.1, 61.1, 55.1 mg/l and 40.4, 56.3, 56.3, 56.6 mg/l and 48, 57.1, 57.1, 58.8 mg/l, respectively.However, the SBR system with yeast strain showed the highest COD removal efficiency of 97.8%and the effluent COD of 48.7 mg/l with HRT of 10 day. And the lowest COD removal efficiency of97% and the effluent COD of 61.1mg/l was found under HRT of 5 days.For treatment of cool storage factory wastewater, the SBR system with yeast strain, yeast strain &bio-sludge, and bio-sludge with HRT of 3 days and initial pH of 5 showed the COD removalefficiency of 96, 96.3 and 96.4%, respectively. And the effluent COD were 91, 81.8 and 80.8 mg/l,respectively.