Experimental Study On Anaerobic Biological Treatment Of PO/MTBE Production Wastewater

It is well known that PO/MTBE production wastewater, which eontains high concentration of organic matters, high COD, high salinity and high ammonia, establishes the difficulty in the chemical industry wastewater, and the treatment of the wastewater in the country is still no mature experience can be used for reference. In this paper, the experimental study fouce on the anaerobic treatment of PO/MTBE production wastewater, contains three main research contents: experimental study on the feasibility of anaerobic treatment, experimental study on two-phase anaerobic combined with zero-value iron technology and experimental study on two-stage anaerobic combined with zero-value iron technology.Anaerobic treatment of PO/MTBE production wastewater is feasible. Feasibility test showed that the removal efficiency of COD was significant in anaerobic treatment. COD removal rate reached a highest value of 50%, gas production was stable, and most of the degradation of pollutants can be completed in 5 days. The influence of salinity on the treatment effect was negligible by the mixed 1:1 of wastewater and water. Maintained p H of the anaerobic system at 7.2 can increase the COD removal rate by about 10%, but the addition of SO42- and S2- also increased the difficulty for anaerobic treatment.Verified the operation effect of the two-phase anaerobic combined with the zero value iron technology. When the influent COD was about 12000mg/L, the lowest reduced to 4100mg/L, and the COD removal rate was 65.8%. Acidogenic phase combined with the zero value iron technology can effectively improve the COD removal rate, reduced the concentration of SO42- and S2-, and improve the biodegradability of wastewater. The COD removal rate of methanogenic phase decreased with the increase of volume loading. When the volume loading increased from 1.0 kg COD/(m3·d) to 1.75 kg COD/(m3·d), the effluent COD increased from 4100mg/L to about 5150mg/L, and the COD removal rate decreased from 34% to 18%. The methanogenic phase didn’t need to regulate the p H and the VFA was basically maintained at 2.6~4.0mmol/L.The deficiency of two-phase anaerobic of PO/MTBE production wastewater was optimized by two-stage anaerobic. The easily degradable pollutants were removed and the undegradable pollutants were modified in theⅠreactor, Ⅱreactor further degraded the modified pollutants and it had a good performance of anti-impact load property. When the influent COD of two-stage anaerobic was about 12000mg/L, HRT=192h, the volume loading of Ⅰreactor was 2.9 kg COD/(m3·d) and the Ⅱreactor was 1.35 kg COD/(m3·d), the effluent COD of Ⅰreactor was about 6000mg/L and its COD removal rate was 45%, the effluent COD of Ⅱreactor was 4000mg/L and its COD removal rate was 33%. Ⅰreactor combined with the zero value iron technology shield the high concentration of SO42- and S2- for Ⅱreactor. The gas produced by the two-stage anaerobic was mainly methane. The two-stage anaerobic reactor had a high microbial diversity, the dominant microflora was similar but the proportion was different.