焦化废水中总氮的构成及在生物工艺中的转化

为了明确焦化废水中总氮的构成及在生物工艺中的转化利用,统计分析了总氮及5种无机含氮化合物在A/O1/O2、A/O1/H/O2和O1/H/O2 3个生物处理工艺中的浓度变化,结合模拟实验研究好氧反应中含氮化合物的氨化作用,并探索高浓度氨氮情况下硝化作用的条件控制。结果表明,总氮由氨氮、硫氰化物、氰化物和有机含氮化合物等构成;氨氮和硫氰化物占总氮比例超过80%,是主要贡献者。模拟实验中在COD和SCN-浓度为4 465和1 238 mg/L水质状况下,控制温度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和SCN-去除率达90%和99%。在O1/H/O2工艺二级好氧池中,氨氮浓度380~400 mg/L时,控制温度23~27℃、pH为7.8~8.3条件下,调试运行23 d实现完全硝化作用。研究证明,影响氨化过程与硝化过程效率的因素包括水质、温度、pH、污泥浓度与停留时间等。

Composition of nitrogeous compounds in coking wastewater and their transformation during biological treatment process

In order to ascertain the composition of nitrogeous compounds in coking wastewater and their transformation during biological treatment process,the concentration variation of total nitrogen,ammonia nitrogen,thiocyanate,cyanide,nitrate and nitrite in different biological treatment stages(A/O1/O2,A/O1/H/O2,O1/H/O2 coking wastewater treatment processes) were analyzed.The ammoniation of nitrogeous compounds on aerobic reaction was investigated through simulative aerobic reactor.Nitrification control under condition of high ammonia concentration were explored.The results showed that the total nitrogen was composed of ammonia nitrogen,thiocyanate,cyanide and organic nitrogen compounds,in which,ammonia nitrogen,thiocyanate accounted for more than 80% of total nitrogen.In simulative aerobic experiment,the concentration of COD,SCN- was fixed at 4 465 and 1 238 mg/L,respectively,when temperature,pH,dissolved oxygen and SV30 were controlled at 17—19℃,7—7.5,1—5 mg/L and 30%,respectively,the removal rate of COD,SCN- could achieve 90% and 99% through a 50.5 h continuous aeration.In secondary aerobic pool during O1/H/O2 process,when ammonia concentration was 380—400 mg/L,temperature was 23—27 ℃,pH was 7.8—8.3,the completely nitrification achieved on the 23rd day of experiment.All the results suggested that the influencing factors of ammoniation and nitrification involved water quality,temperature,pH,sludge concentration and hydraulic retention time.