混凝与AB法联用处理制革废水

针对制革废水SS、有机物、总Cr及色度较高的特点,采用混凝与AB法联合工艺处理。试验研究了混凝的条件和处理效果;分别研究了AB法的A、B两段HRT和有机负荷对处理效果的影响。研究结果表明:调节pH值为8.8～10.0,PAC的投加量为300～400 mg/L,混凝单元对制革废水的SS、色度、总Cr和CODCr的平均去除率分别为64.3%、69.2%、97.5%和23.5%;AB法的A段在HRT为50～55 min、DO质量浓度为0.8～1.2mg/L时,CODCr的去除率不小于48%,CODCr负荷达到15～17.8 kg/(m3.d);B段在HRT为8～10 h、DO质量浓度为2.5～3.0 mg/L时,CODCr的去除率不小于75%,CODCr负荷为0.55～0.75 kg/(m3.d)。制革废水经该工艺处理的出水达到GB 8978—1996《污水综合排放标准》的一级标准。

Treatment of tanning wastewater by combined technology of coagulation and AB method

In view of the fact that tanning wastewater contains high concentration of SS,organic matters,total Cr and chroma,a combined technology of coagulation and AB method was used for its treatment.The treat-ment effect under different coagulation conditions was investigated;besides,the influences of HRT of section A and section B of the AB method and the organic loading on the treatment effect were studied respectively.The results of the test showed that: when the pH value was adjusted to 8.8-10.0,and the PAC dosage was 300-400 mg/L,the average removal rates of SS,chroma;total Cr and CODCr in tanning wastewater by coagulation were 64.3%、69.2%、97.5% and 23.5% respectively.In the section A of the AB method,when the HRT was 50-55 min,the mass concentration of DO was 0.8-1.2 mg/L,the removal rate of CODCr was not below 48%,and the CODCr loading reached 15-17.8 kg/(m3·d);and in the section B of the AB method,when the HRT was 8-10 h,the mass concentration of DO was 2.5-3.0 mg/L,the removal rate of CODCr was not below 75%,and the CODCr loading was 0.55-0.75 kg/(m3·d).The effluent quality of the tanning wastewater after the treatment by the said technology reached the first criteria specified in GB 8978—1996 Integrated Wastewater Discharge Standard.