长反应时间条件下乙醛废水碱解脱毒预处理效果

乙醛废水含有高浓度醛类及有机氯类有毒有机物,对废水生物处理系统中的微生物抑制性强,直接生物处理难度较大,需进行脱毒预处理。考察了延长反应时间和提高反应温度对乙醛废水碱解脱毒所需碱(NaOH)投加量的影响。结果表明:碱解预处理可有效去除废水中的醛类和有机氯类有毒有机物,显著降低废水厌氧生物毒性和好氧生物毒性;以厌氧生物毒性作为脱毒评价指标较有毒物质浓度更为合理;延长反应时间、提高反应温度有利于降低乙醛废水充分脱毒所需碱的投加量;将反应时间由3 h延长至10 h,反应温度由60 ℃升至70 ℃,乙醛废水充分脱毒所需碱的投加量降低了50%,节省药剂成本约3.7元∕t(以废水计)。

Alkaline detoxification pretreatment of acetaldehyde wastewater under the condition of long reaction time

Acetaldehyde wastewater contains high concentration of toxic organic compounds, including aldehydes and organochlorines. It has strong inhibition on the microorganisms in wastewater biological treatment system, and it is difficult to treat directly by biological treatment, so detoxification pretreatment is needed. The effects of prolonging reaction time and raising reaction temperature on the dosage of alkali required for alkaline detoxification of acetaldehyde wastewater were investigated. The results indicated that alkaline pretreatment could effectively remove aldehydes and organochlorine toxic organic compounds from wastewater, and significantly reduce the anaerobic biological toxicity and aerobic biological toxicity of wastewater. The anaerobic biological toxicity was more reasonable for the evaluation of detoxification efficiency than the concentration of toxic substances. Prolonging reaction time and raising reaction temperature were beneficial to reducing the alkali dosage required for sufficient detoxification of acetaldehyde wastewater. When the reaction time was prolonged from 3 h to 10 h, the reaction temperature was raised from 60 ℃ to 70 ℃, the alkali dosage required for the sufficient detoxification was reduced by 50%, and the cost of regents saved by about 3.7 yuan per ton of wastewater.