【作者】 张伟；

【导师】 何成达； 丛海兵；

【作者基本信息】 扬州大学 ， 市政工程， 2020， 硕士

【摘要】 化工废水处理是水处理中的难点和热点之一,随着排放标准进一步提高,低浓度难降解化工废水深度处理技术尚待进一步研发。本研究以化工企业处理过的废水为对象,研究化工废水深度处理技术。研究过程中选择陶粒、钢刨花、颗粒氮化碳、活性炭负载铁、铁碳球等催化剂进行臭氧催化氧化实验,以臭氧单独氧化作为对照,研究臭氧氧化过程中,催化剂种类、臭氧投加量、废水初始pH等因素对COD去除效果的影响。并利用顶空固相微萃取—气质联用仪,分析了铁碳球催化臭氧氧化工艺前后,废水中有机物种类、占比的相对变化情况。最终针对实验用低浓度化工废水形成了铁碳臭氧催化氧化+厌氧活性焦生物滤池+好氧活性焦生物滤池的组合工艺,对废水中的COD及含氮物质分别处理。通过研究,得出结论如下:1.在废水臭氧氧化研究中,加入催化剂进行臭氧催化氧化,其处理效果明显优于单独臭氧氧化;经过催化剂的筛选,在废水臭氧催化氧化中,铁碳球催化剂催化作用优于实验中选取的陶粒、钢刨花、颗粒氮化碳等催化剂。2.采用铁碳球为催化剂的臭氧催化氧化,对此种低浓度化工废水COD有明显的去除效果。在废水初始pH为8、臭氧投加率为3mg/(L·min)、反应时间为1h的条件下,COD由186mg/L下降到117mg/L,去除率为37.1%,B/C由0.07提高到0.33。3.废水经臭氧催化氧化处理后,可生化性有明显改善。好氧生物膜法处理臭氧催化氧化出水,挂膜载体不同,对COD去除率存在一定影响;4h停留时间条件下,活性焦填料较常规塑料填料好氧生物膜法,COD去除效果更好,COD去除率分别为39%与35%,同时废水中少量的氨氮能够有效地转化为硝态氮。厌氧生物膜法处理臭氧催化氧化出水时,挂膜载体不同,对COD与硝态氮的去除存在少量影响;相同的停留时间下,外加60～70mg/L的碳源,活性焦填料较常规塑料填料厌氧生物膜法,COD去除率与硝态氮去除率存在一定提升。4.就实验研究的低浓度化工废水而言,采用臭氧催化氧化+厌氧活性焦生物滤池+好氧活性焦生物滤池组合工艺,工业废水COD由181mg/L下降至73mg/L,氨氮由4.lmg/L下降到0.2mg/L,硝态氮由20.8mg/L下降至3.7mg/L,亚硝态氮基本检测不出。出水水质达到《化工工业主要水污染物排放标准》(DB32/939-2006)中规定的集中式工业污水处理厂一级排放标准。5.针对低浓度难降解化工废水,采用臭氧催化氧化是关键技术手段。以铁碳球为催化剂的臭氧催化氧化工艺主要利用臭氧催化氧化过程中产生的羟基自由基来氧化降解废水中的COD。羟基自由基对有机物C-O键等官能团作用,进而引发类似烷烃卤代反应的链式反应,使得有机物裂解,促进有机物氧化分解。更多还原

【Abstract】 Chemical wastewater treatment is one of the difficulties and hot spots in water treatment.With the further improvement of discharge standard,the advanced treatment technology of low concentration and difficult degradation chemical wastewater needs further research and development.In this study,the advanced treatment technology of chemical wastewater was studied.In the research process,ceramsite,steel shaving,granular carbon nitride,activated carbon loaded iron,iron carbon ball and other catalysts were selected to carry out the ozone catalytic oxidation experiment.With ozone alone oxidation as a control,the effects of catalyst type,ozone dosage,initial pH of wastewater and other factors on the removal of cod were studied.By using headspace solid-phase microextraction GC-MS,the relative changes of the types and proportions of organic compounds in wastewater before and after the process of iron carbon sphere catalytic ozonation were analyzed.Finally,a combined process of Fe-C-O catalytic oxidation+anaerobic activated coke biofilter+aerobic activated coke biofilter was formed to treat the COD and nitrogen-containing substances in the wastewater.Through the research,the conclusion is as follows:1.In the study of ozonation of wastewater,adding catalyst for ozonation is better than ozonation alone.Through the selection of catalyst,in the ozonation of wastewater,the catalytic effect of iron carbon sphere catalyst is better than that of ceramsite,steel shaving,granular carbon nitride and other catalysts selected in the experiment2.Using iron carbon ball as catalyst for ozone catalytic oxidation,this kind of low concentration chemical wastewater COD has obvious removal effect.When the initial pH of wastewater is 8,the ozone addition rate is 3 mg/(L·min)and the reaction time is 1 h,COD decreases from 186 mg/L to 117 mg/L,the removal rate is 37.1%,and B/C increases from 0.07 to 0.33.3.The biodegradability of the wastewater is improved obviously after the treatment of ozone catalytic oxidation.The removal efficiency of COD is better under the condition of 4H residence time than that of conventional plastic packing.The removal efficiency of COD is 39%and 35%respectively.At the same time,a small amount of ammonia nitrogen in wastewater can be effectively converted into nitrate nitrogen.When the anaerobic biofilm process is used to treat the effluent of ozone catalytic oxidation,the different membrane carriers have a small impact on the removal of COD and nitrate nitrogen;under the same residence time,plus 60～70mg/L carbon source,the removal rate of COD and nitrate nitrogen of the activated coke packing is higher than that of the conventional plastic packing anaerobic biofilm process.4.As far as the low concentration chemical wastewater is concerned,the combined process of ozone catalytic oxidation+anaerobic activated coke biofilter+aerobic activated coke biofilter is adopted.The COD of industrial wastewater is reduced from 181mg/L to 73mg/L,the ammonia nitrogen is reduced from 4.1mg/l to 0.2mg/l,the nitrate nitrogen is reduced from 20.8mg/l to 3.7mg/l,and the nitrite nitrogen is basically undetectable.The water quality of the effluent meets the primary discharge standard of the centralized industrial sewage treatment plant specified in the discharge standard of main water pollutants in the chemical industry(DB32/939-2006).5.In view of the low concentration and refractory chemical wastewater,ozone catalytic oxidation is the key technology.The process of ozone catalytic oxidation with iron carbon spheres as catalyst mainly uses hydroxyl radicals produced in the process of ozone catalytic oxidation to oxidize and degrade COD in wastewater.Hydroxyl radicals act on functional groups such as C-O bond of organic compounds,and then lead to chain reaction similar to alkane halogenation reaction,which makes organic compounds split and promotes the oxidation and decomposition of organic compounds.更多还原