焦化废水中无机含氮化合物在生物处理工艺中的去除行为研究

发布时间：2018-03-19 23:22

  本文选题：A/O1/O2工艺　切入点：A/O1/H/O2工艺　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：焦化废水是煤制焦炭、煤气净化及焦化产品回收过程中产生的工业废水。其中含氮化合物种类丰富,含氮量较高。在新国标要求焦化废水总氮排放低于20 mg/L的形势下,很多企业将面临着技术改进方面的挑战。所以研究焦化废水中总氮的主要来源及其在生物处理工艺中的去除和转化,可以为总氮减排的工艺优化和工程运行提供指导和依据。首先,为了明确焦化废水中总氮的主要来源,以A/O1/O2、A/O1/H/O2、O1/H/O2 3个生物处理工艺为案例,统计分析了总氮及5种无机含氮化合物在原水和各生物单元反应器进出水中的浓度变化,研究了组成焦化废水中总氮的主要组分形态、所占比例及互相转化。结果表明:3个厂区焦化废水原水中总氮浓度从250 mg/L~620 mg/L不等,主要由氨氮(NH4+-N)、硫氰化物(SCN-)、氰化物(CN-)等组成,氨氮和硫氰化物占总氮比例超过80%,是主要贡献者。含氮化合物在三种生物处理工艺中的转化相似,主要包括两个阶段,第一阶段,硫氰化物、氰化物在一级好氧处理过程基本转化为氨氮;第二阶段,氨氮在二级好氧处理过程中经亚硝化再硝化最终转化为硝酸盐。而后为了研究主要含氮化合物氨氮、硫氰化物、氰化物及其他污染物COD、挥发酚、硫化物在生物处理工艺中的降解,以调试运行阶段的天津天铁炼焦厂O1/H/O2焦化废水处理工艺为研究对象,研究了各单元反应器对主要含氮化合物氨氮(NH4+-N)、硫氰化物(SCN-)、氰化物(CN-)及其他污染物COD、挥发酚、硫化物的去除效果并分析其原因。结合模拟实验研究了好氧反应中这些污染物的好氧降解与工艺指标污泥沉降比(SV30)、水力停留时间(HRT)的关系,并分析了微生物对这些污染物的降解先后顺序。结果表明:在O1/H/O2工艺中,O1反应器对SCN-、氰化物、COD、挥发酚、硫化物的去除率均高于90%,同时SCN-、氰化物被转化为氨氮。在O2反应器中,影响硝化过程的因素包括氨氮浓度、亚硝酸根浓度、温度、pH等,当氨氮浓度380 mg/L~400mg/L时,控制温度23~27℃、pH为7.8~8.3条件下,调试运行23天实现氨氮的完全硝化,。另外,在模拟含氮化合物的好氧降解实验中,在水质指标COD、SCN-浓度为4465mg/L、1238 mg/L状况下,实验条件为温度17~19℃、pH 7~7.5、溶解氧1~5 mg/L、SV30为30%,连续曝气50.5 h时实现COD、SCN-去除率达90%、99%。并且,微生物优先降解酚类、氰化物、硫化物,随着毒性抑制作用的降低,微生物开始降解SCN-,当SCN-完全降解时,COD也降低到最低点。
[Abstract]:Coking wastewater is a kind of industrial wastewater produced in the process of coal coking, gas purification and coking product recovery, in which nitrogen compounds are abundant and nitrogen content is high. Under the new national standard, the total nitrogen discharge of coking wastewater is less than 20 mg/L. Many enterprises will face technical improvement challenges. Therefore, the main sources of total nitrogen in coking wastewater and their removal and conversion in biological treatment processes are studied. It can provide guidance and basis for the process optimization and engineering operation of total nitrogen emission reduction. First, in order to determine the main sources of total nitrogen in coking wastewater, take the biological treatment process A / O _ 1 / O _ 2 / A / O _ 2 / O _ 2 / O _ 1 / H / O _ 2 as an example. The concentration changes of total nitrogen and five inorganic nitrogen compounds in raw water and in the inlet and outlet water of each bioreactor were analyzed statistically. The main components of total nitrogen in coking wastewater were studied. The results showed that the concentration of total nitrogen in raw water of coking plant wastewater ranged from 250 mg/L~620 mg/L to 250 mg/L~620 mg/L, mainly composed of ammonia nitrogen (NH _ 4-N _ 4), sulfur cyanide (SCN-N), cyanide (CN-N), etc. Ammonia nitrogen and thiocyanate account for more than 80% of total nitrogen, and they are the main contributors. The conversion of nitrogen-containing compounds in the three biological treatment processes is similar, including two stages, the first stage, the sulfur cyanide, Cyanide is basically converted to ammonia nitrogen during primary aerobic treatment; in the second stage, ammonia nitrogen is converted to nitrate by nitrification and denitrification during the second stage of aerobic treatment. Then, in order to study the main nitrogen-containing compounds, ammonia nitrogen, sulfur cyanide, Degradation of cyanide and other pollutants such as COD, volatile Phenol and Sulfide in Biological treatment process. The treatment process of O 1 / H / O 2 coking wastewater from Tianjin Tiantie Coking Plant was studied. The effects of various unit reactors on NH _ 4-N _ 4, sulfur cyanide (SCN-N), cyanide (CN-) and other pollutants, such as COD, volatile phenol, were studied. The relationship between aerobic degradation of these pollutants in aerobic reaction and sludge sedimentation ratio (SV30) and HRT (HRT) was studied. The results showed that the removal rate of SCN, cyanide COD, volatile phenol and sulphide in O 1 / H / O 2 reactor was higher than 90%, and SCN and cyanide were converted to ammonia nitrogen in O2 reactor. The factors influencing nitrification process include ammonia nitrogen concentration, nitrite concentration, temperature and pH, etc. When ammonia nitrogen concentration is 380 mg/L~400mg/L, the control temperature is 23 ~ 27 鈩，

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