การบำบัดก๊าซจากโรงงานยางแท่ง STR20 ด้วยระบบเอสบีอาร์

Abstract

The study of treatment of emitted gases from block rubber STR20 factory with sequencing batch reactor system is to investigate the efficiency of emitted gases treatment with a co-current flow wet scrubber system. The exhausted gases from the STR 20 factory consisted of volatile fatty acids gases (VFAs), hydrogen sulfide (HS) and ammonia (NH,). In this study, influent and effluent gases and absorbed water samples were taken from the 1" unit of wet scrubber. The sampling was conducted for 7 weeks. Results showed that the wet scrubber system could reduce the temperature of those gases by average value of 6 °C. Besides, the average efficiency treatment of VFAs such as isovaleric acid, isobutyric acid, valeric acid, butyric acid, propionic acid, and acetic acid were 47%, 46%, 46%, 40%, 39%, and 32%, respectively, and H,S removal was found to be with an average value of 14%. Moreover, the examination of the absorbent water revealed that after the water was used to absorb gases, its temperature approximately increased by 9.3 °C of average value. In addition, the concentrations of VFAS, SCOD, TKN, SS, NH,-N, H,S, and S2 in absorbent water were determined to be higher than before absorption. For the experiments to investigate the co-treatment efficiency of effluent gases and effluent absorbent wastewater from wet scrubber of STR20 factory by using SBR, 4 sets of reactors (R1-R4) were tested with 2 conditions of wastewater feeding, namely feeding once a day and twice a day. The gases feeding rate to reactor R3 was 13.3 1/m3 (L/G ratio of 0.188 1/m3 and 0.423 1/m3). The reactor R4 had gases feeding rate of 6.65 1/m3 (L/G ratio of 0.376 1/m3 and 0.846 1/m3). The results revealed that treatment of wastewater of SBR units (R1, R3 and R4) and R2, (not SBR system) could remove organic matter. The obtained effluent wastewater could meet the industrial effluent standard announced in 1996. The experimental set running with twice a day of wastewater feeding gave the better wastewater treatment than once a day of wastewater feeding. The R4 reactor with L/G ratio of 0.846 1/m3 gave the highest efficiency of wastewater treatment. For gases treatment, it was observed that temperature of effluent gases was reduced 9.5°C and 8.2 °C by average in the reactors running with once a day and twice a day of wastewater feeding, respectively. For 5 types of VFAs gases treatment, it was found that with once a day of wastewater feeding in R3 reactor, the average efficiency treatment of acetic acid, propionic acid, butyric acid, valeric acid and isovaleric acid were 9%, 77%, 66%, 52% and 87%, respectively, but in R4 reactor, the average treatment of acetic acid, propionic acid, butyric acid, valeric acid and isovaleric acid were 9%, 77%, 65%, 52% and 87%, respectively. In addition, HS removal efficiency of R3 and R4 reactors with twice a day of wastewater feeding was found to be 17% and 31% as of average values, but in R2 reactor, only 25% was found. For NH, removal in R2, R3 and R4 reactors, running with once a day feeding with wastewater, was determined to be 43%, 29% and 32% by average, respectively. It was found that there were 4 types of mechanisms happened in the reactors investigated in this study. Those were bio- degradation, air stripping, absorption and dilution.