| With the rapid development of my country’s livestock and poultry breeding industry,the discharge of livestock and poultry wastewater has gradually increased,and biogas projects have also developed rapidly.The advantages of anaerobic fermentation technology for the treatment of high-concentration organic wastewater are becoming more and more obvious.However,the existing single-phase anaerobic process is prone to "acidification" when processing high-concentration organic wastewater,resulting in abnormal reactor operation,thereby reducing the reactor Processing efficiency.Zerovalent iron as an auxiliary factor for the activity of a variety of key enzymes to assist anaerobic digestion.Biological activated carbon as a filler in an anaerobic reactor can effectively maintain an anaerobic environment,promote hydrolysis and acidification,and improve the reactor’s ability to treat pollutants,but There are few reports and studies on the effects of zero-valent iron and biological activated carbon on the anaerobic reactor.Therefore,this study carried out the research on the effect of zero-valent iron activated carbon added with enhanced medium temperature two-phase anaerobic treatment of swine wastewater.This study investigated the medium-temperature two-phase anaerobic reactor as the main process,and studied the treatment efficiency and operating stability of the reactor.The effects of different Fe/C ratios on strengthening treatment were explored.Under the optimal Fe/C ratios,the effect of HRT on mid-temperature two-phase anaerobic anaerobic conditions was established,and a two-phase anaerobic digestion reaction kinetic model was initially established.By inspecting various indicators of effluent,characterizing the operation status of the reactor,it provides good technical support for the treatment of intensive aquaculture wastewater.(1)After the 60-day sludge domestication and cultivation of the mid-temperature two-phase anaerobic reactor,the treatment efficiency of the reactor was investigated by controlling the volume load.The results showed that when the acid generating reactor had a volume load of 16 kg COD/(m3·d),The average removal rate of COD is 44%;the average removal rate of COD in the methanogenic reactor is 83%.The total removal rate of COD reached 93%,the total removal rate of TN reached about 50%,the total removal rate of NH4+-N was 22%,the effluent concentration did not exceed 25.4 mg/L,and anaerobic ammonia suppression did not occur,while the value of volatile fatty acids(VFAs)remained At lower levels,VFAs<400mg/L,no "acidification" phenomenon,but TP removal effect is poor.(2)Different influent p H has a greater impact on the reactor.When the influent p H of the acid-generating reactor is 5-6.5,and the influent p H of the methane-generating reactor is 7-7.5,the reactor has better treatment effect on COD and TN.,COD total removal rate> 80%,TN total removal rate> 31%.(3)Adding different Fe/C ratio to treat pig farm wastewater COD removal effect sequence: 1:1>1:2>2:1,under the optimal ratio of 1:1,the COD removal rate increased by 13.5 %,TN removal rate increased by 14.5%.However,different ratios had no significant effect on NH4+-N,TP and p H of the effluent.Scanning electron microscopy was used to characterize the biologically activated carbon with the best Fe/C ratio before and after the reaction.The pores of the activated carbon narrowed,and a large amount of bacterial micelles and grains were adsorbed on the surface.(4)For the case where the Fe/C is determined to be 1:1 ratio in the middle temperature two-phase anaerobic digestion,the HRT of the acid generator is 24 h,the HRT of the methanogen is 48 h,and the total COD removal rate is 94%.The TFe concentrations of the two-phase reactor were 3.04mg/L and 2.45mg/L,respectively,and the SS removal rate was 83%.At the end of the thesis,a preliminary study on the kinetic reaction order of pig-wastewater treatment with iron-carbon medium-temperature twophase anaerobic process is carried out.The results show that the addition of iron-carbon to the acid-generating reactor basically conforms to the three-stage reaction kinetic law;After adding iron-carbon,it basically conforms to the law of zero-order reaction kinetics.As an electron donor,zero-valent iron has a good effect on the treatment of farming wastewater,and is feasible.Zero-valent iron and biological activated carbon are economically applicable,easy to use,and provide a path for energy recovery and saving of waste iron.The results of this study also provide a theoretical basis for the intensive anaerobic treatment of intensive livestock and poultry farming wastewater. |
