UASB—好氧—混凝工艺处理高盐榨菜废水研究

Study on the treatment of mustard tuber wastewater with high salinity by UASB-aerobic-coagulation process

针对榨菜废水呈高盐、高有机物浓度的水质特征,对UASB—好氧—混凝工艺处理采用盐脱水工艺所产生的榨菜废水的效能进行了研究。试验结果表明,UASB的最佳反应条件是:盐质量浓度(以NaCl计)不超过46 g/L,有机负荷不超过15.0 kg/(m3.d),温度38℃,pH在6.8～7.2;而在兼性氧化反应器和好氧接触氧化反应器中,DO保持在>4 mg/L,HRT控制在20～24 h时,COD的去除率最高;在混凝过程中,当聚合氯化铝(PAC)投加质量浓度为200mg/L时,pH在6.4～7.8,出水的COD最低。经UASB—好氧—混凝工艺处理后,三个工艺段废水COD的去除率分别为45%、60%、61.7%,出水COD约为78 mg/L,总去除率>90%,达到《污水综合排放标准》(GB 8978—1996)一级标准。

The mustard tuber wastewater is characterized by high salinity and high organic matter concentration.The efficiency of using UASB-aerobic-coagulation process for treating mustard tuber wastewater from the desalting technology has been studied.The results show that the best reaction conditions of UASB are as follows： the salt mass concentration（calculated as NaCl） is lower than 46 g/L,the organic loading not higher than 15.0 kg/（m3·d）,temperature 38 ℃ and pH 6.8-7.2.The removal rate is the highest,when it is in the facultative oxidation reactor and aerobic-contact oxidation reactor,DO is 4 mg/L,and HRT is 20-24 h.The COD of effluent water is the lowest,during the process of coagulation,when the mass concentration of PAC dosage is 200 mg/L,and pH 6.4-7.8.After treated by the UASB-aerobic-coagulation process,the wastewater COD removal rates of the three units are 45%,60%,and 61.7%,respectively,the effluent COD is about 78 mg/L,and the total removal rate is higher than 90%,meeting the first class of Integrated Standard of Wastewater Discharge（GB 8978—1996）.