有机废水中硫酸盐和氨的厌氧转化机制研究

Study on anaerobic conversion mechanism of sulfate and ammonia in organic wastewater

采用逐步提升进水n(NH_(4)^(+)-N)/n(SO_(4)^(2-))比的方式,在厌氧有机条件下(ORP=(-334.3±18.2)mV,DO=(0.10±0.5)mg/L)在上流式厌氧污泥床(UASB)反应器中实现了硫酸盐还原-氨氧化(SRAO),研究了不同COD对氮硫脱除性能的影响,通过对SRAO反应产物、不同阶段运行结果的分析并结合微生物菌群变化规律探讨了其转化机制.结果表明,SRAO反应是SO_(4)^(2-)将NH_(4)^(+)-N氧化为NO_(2)^(-)-N并生成S积累在污泥相,中间产物NO_(2)^(-)-N被自养/异养反硝化菌还原,一部分SO_(4)^(2-)被硫酸盐还原菌(SRB)还原为S^(2-),各微生物之间协同代谢实现了系统内氮硫的同步去除.提高进水N/S比可以使NH_(4)^(+)-N更多的转化为NO_(2)^(-)-N被反硝化菌利用,但当N/S比提升至4时,硫自养反硝化作用强烈会影响SO_(4)^(2-)的脱除,反应器内硫自养反硝化菌属(Thiobacillus)的丰度在这一阶段增加了3.36%.在不含有机物的无机条件下,未发生NH_(4)^(+)-N与SO_(4)^(2-)的同步去除.提高进水COD至150mg/L,促进了SRAO反应与反硝化作用的耦合,提高了系统的脱氮除硫性能,反应器内SRB菌属(Desulfococcus、Desulfatiglans)和多种反硝化菌属(Methyloversatilis、Longilinea、Simplicispira、Bdellovibrio、Azospira等)的总丰度分别增加了1.584%和6.081%.当COD=250mg/L时,硫酸盐还原反应增强产生较多S^(2-)则会抑制SRAO反应活性,影响系统内NH_(4)^(+)-N的脱除.

By gradually increasing the influent n(NH_(4)^(+)-N)/n(SO_(4)^(2-))ratio,sulfate reduction-ammonia oxidation(SRAO)was achieved in an up-flow anaerobic sludge blanket(UASB)reator under anaerobic organic conditions(ORP=(-334.3±18.2)mV,DO=(0.10±0.5)mg/L).The effects of different COD on the removel performance of nitrogen and sulfur were studied.The transformation mechanism was discussed by analyzing the SRAO products,the operation results of different stages and the variation of microbal flora.The results showed that the SRAO was that SO_(4)^(2-)oxidized NH_(4)^(+)-N to NO_(2)^(-)-N and generated S to accumulate in the sludge phase.The intermediate product NO_(2)^(-)-N was reduced by autotrophic/heterotrophic denitrifying bacteria,and part of SO_(4)^(2-)was reduced to S^(2-)by sulfate reducing bacteria(SRB).Synergistic metabolism among microorganisms achieved simultaneous removal of nitrogen and sulfur in the system.Increasing the influent N/S ratio can make more NH_(4)^(+)-N converted to NO_(2)^(-)-N to be utilized by denitrifying bacteria,but when the N/S ratio was increased to 4,the sulfur autotrophic denitrification strongly affected the removal of SO_(4)^(2-),and the abundance of Thiobacillus in the reactor increased by 3.36% at this stage.The simultaneous removal of NH_(4)^(+)-N and SO_(4)^(2-)did not occur under inorganic conditions without organic matter.Increasing the influent COD concentration to 150mg/L promoted the coupling of SRAO and denitrification,and improved the nitrogen and sulfur removal performance of the system.The total abundance of SRB(Desulfococcus,Desulfatiglans)and various denitrifying bacteria(Methyloversatilis,Longilinea,Simplicispira,Bdellovibrio,Azospira,etc.)in the reactor increased by 1.584% and 6.081%,respectively.When COD=250mg/L,the enhanced sulfated reduction reaction produced more S^(2-),which inhibited the SRAO activity and affected the removal of NH_(4)^(+)-N in the system.