| Because of its strong acidity,high organic content,high sulfate content,and poor biodegradability,acidified vegetable oil wastewater faced the problems of high treatment cost and poor treatment effect in practical engineering applications.This subject took the acidified vegetable oil wastewater from an industrial company in Dongguan City,Guangdong Province as the research object.According to the pollution characteristics of wastewater and the problems in wastewater treatment engineering,a process method for treating acidified vegetable oil wastewater using anaerobic sequential batch reactor?ASBR?was proposed.The start-up mode,treatment efficiency,parameter optimization and substrate degradation kinetics of the reactor were studied to provide a theoretical basis for engineering applications.The ASBR adopted different load starting methods to treat acidified vegetable oil wastewater was studied.The study found that under low-load start-up conditions?the previous wastewater was diluted?,the sludge could more quickly adapt to the shock load of high-concentration acidified vegetable oil wastewater.At this time,the reactor had higher organic matter removal efficiency and less volatile fatty acids?VFA?,sulfide accumulation.Under low-load start-up condition and high-load start-up condition,the average COD removal rates after stabilization were 51.2%and 40.2%,respectively;the average cumulative concentrations of VFA after stabilization were 1069 mg·L-1 and 1225 mg·L-1,respectively;and the average accumulated concentrations of sulfides after stabilization were 47.8 mg·L-1 and 77.6 mg·L-1,respectively.The important influencing factors and treatment efficiency of the treatment of acidified vegetable oil wastewater with stable ASBR were studied.The results showed that the fluctuation of p H,sulfide concentration and VFAs concentration in one reaction cycle was small and the removal rate of COD was 15%?20%under the condition of initial p H=5,5.5 of anaerobic reaction.Whereas,the p H,sulfide concentration,VFAs concentration fluctuated greatly and the COD removal rate was 50%?60%under the initial p H=6,6.5,7,7.5,8.According to the relationship between ASBR treatment efficiency and wastewater retention time of plant acidified oil wastewater at different initial p H,a multiple nonlinear regression model of quantitative relationship amoung initial p H,wastewater retention time and COD removal rate was established,and the model was highly significant.It could be seen from the model conclusion that the maximum COD removal rate was at the initial p H of 7.5 and the wastewater retention time of 84h.The substrate degradation kinetics of the anaerobic reaction of acidified vegetable oil wastewater under optimized conditions was studied.The results showed that during the period of rapid substrate degradation,COD was quickly removed,and the substrate specific degradation rate was high.The model“=507.6-?2.633×106?/?S-4390?could better describe the substrate degradation process at this time;during the inhibition period,the COD removal rate droped rapidly,and the substrate specific degradation rate was low,the describe the substrate degradation process at this time. |
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