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反硝化脱硫工艺运行效能及影响因素研究

Treatment Performance and Factors of Denitrifying Sulfide Removal Process

【作者】 郭磊

【导师】 王爱杰;

【作者基本信息】 哈尔滨工业大学 , 环境科学与工程, 2008, 硕士

【摘要】 碳氮硫同步脱除工艺系统能够同时去除废水中碳、氮及硫三大类污染物,具有工艺简单、运行成本较低、无二次污染、可回收单质硫,实现资源化等优点。该工艺系统由硫酸盐还原、反硝化脱硫及硝化三个处理单元组成,其中反硝化脱硫单元是工艺系统的核心单元,创造自养反硝化菌和异养反硝化菌共存的混养生态系统,实现对硫化物、乙酸盐和硝酸盐的同时去除并积累单质硫。本研究在探讨反硝化脱硫工艺处理效能的基础上,采用单因子法分别考察了硫酸盐还原工艺出水中的有机物、硫酸根、氨氮及硝化工艺回流水中的亚硝酸盐对反硝化脱硫过程的影响,以期为工艺系统的串联运行提供依据。采用膨胀颗粒污泥床(EGSB)反应器探讨反硝化脱硫工艺的运行效能,在HRT为10h,进水硫化物浓度为800mg/L时,硫化物的去除率超过92%,理论单质硫转化率为100%,乙酸盐的去除率稳定在100%,硝酸盐的去除率约85%。有机物对反硝化脱硫工艺的影响试验结果表明,乙酸盐与硝酸盐的比例(C/N)在0.75~1.26时对反硝化脱硫效果的影响较小;C/N为0.75时,硫化物和乙酸盐的去除率均为100%,硝酸盐去除率最低在90%左右;C/N为1.0时,反硝化脱硫的效果最好,硫化物、乙酸盐及硝酸盐的去除率均为100%;C/N为1.26时,乙酸盐和硝酸盐的去除率均为100%,硫化物去除率为92%。试验过程中,单质硫累积效果较好,去除的硫化物全部转化为单质硫。在进水硫化物浓度为200mg/L,硫化物、乙酸盐及硝酸盐的摩尔比为1:1:1时考察了不同硫酸盐和氨氮浓度对反硝化脱硫工艺的影响。结果表明,两种浓度分别为170mg/L~540mg/L和100mg/L~800mg/L时,对反硝化脱工艺基本无影响;硫酸盐未发生还原;由于氨氮的电离平衡作用,出水氨氮略微有所降低。本研究发现,亚硝酸盐对反硝化脱硫过程没有任何抑制,而且还可以作为反硝化脱硫过程的唯一电子受体。在硝酸盐浓度为388mg/L,亚硝酸盐浓度在100mg/L、200mg/L、400mg/L各阶段变化时,硫化物和乙酸盐的去除率均为100%,硝酸盐去除率保持在80%左右;亚硝酸盐单独存在时,浓度在400mg/L、500mg/L、600mg/L各阶段变化时,自养反硝化菌和异养反硝化菌都能利用亚硝酸盐作为电子受体,乙酸盐的去除率一直保持在100%,硫化物的去除率由80%左右逐渐增加至100%,亚硝酸盐的去除率从100%下降至80%左右。

【Abstract】 The process of simultaneous removal of carbon, nitrogen and sulfur is able to removal carbon, nitrogen and sulfur simultaneously in wastewater. It has many advantages for example low operating costs, no secondary pollution, recoverying elemental sulfur, implementing resources. The process is composed of sulfate reduction(SR), denitrifying sulfur removal(DSR)and nitration. The core unit is denitrifying sulfur nemoval process, which can cultivate autotrophic dinitrifying bacterium and heterotrophic denitrificans to remove sulfide, acetate and nitrate simultaneously with elemental sulfur accumulation.In this study, on the basis of investigating the treatment performance of denitrifying sulfur removal(DSR)process, the factors of the denitrifying sulfur removal(DSR)process including organism, sulfate, ammonia from SR process and nitrite from nitration process were discussed.Expanded granular sludge bed(EGSB)reactor was used to investigate the treatment performance of the denitrifying sulfur remova(lDSR)process. At hydraulic retention time(HRT)of 10h and the influent sulfide concentration of 200mg/L, sulfide removal rate exceeded 92%, elemental sulfur conversion rate was 100%, acetate removal rate was stable at 100%, nitrate removal ratio was about 85%.The experimental results showed that organism had less effect on denitrifying sulfur removal(DSR)at C/N ratio of 0.75:1~1.26:1. With C/N=0.75:1, sulfide and acetate removal rates were all 100% and nitrate removal rate was about 90%; At C/N=1.0:1, the denitrifying sulfur removal(DSR)had the best performance and sulfide, acetate and nitrate removal rates were all 100%; At C/N=1.0:1, acetate and nitrate removal rates were all 100% and sulfide removal rate was 92%. In this experiment, the removed sulfide was all oxidized to elemental sulfur(S0).With the influent sulfide concentration at 200mg/L and with fixed C/N/S=1:1:1, the experiment analyzed effects of sulfate and ammonia on denitrifing sulfide removal(DSR)process respectly. The results showed that sulfate concentration at 170mg/L~540mg/L and ammonia concentration at 100mg/L~800mg/L had less effect on denitrifying sulfur removal(DSR)process. In the process, sulfate concentration wasn’t reduced and the outfluent ammonia concentration is less than the influent because of the ionization of ammonia.This study showed that nitrite didn’t inhibit the denitrifying sulfide removal(DSR)process and it might be sole electron acceptor. With nitrate concentration at 388mg/L, three nitrite concentrations—100mg/L, 200mg/L and 400mg/L—were applied to the EGSB reactor.The sulfide and acetate removal rates were all100%, nitrate rmoval rate was kept at 80%. With no nitrate in denitrifying sulfide removal( DSR ) process, three nitrite concentrations—400mg/L, 500mg/L and 600mg/L—were applied to the reactor. In the process, autotrophic dinitrifying bacterium and heterotrophic denitrificans could all use nitrite as electron acceptor, acetate removal rate was always kept at 100%, sulfide removal rate was from 80% to 100%, but nitrite removal rate was from 100% to 80%.

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