加载絮凝-污泥回流工艺处理重金属废水的研究

Study on ballasted flocculation-sludge return process for treatment of heavy metal-containing wastewater

电子行业废水的重金属处理通常采用混凝沉淀方法。然而,常规混凝方法存在药剂投加量大、污泥产量多、水质波动影响大等不足。因而,本文提出了加载絮凝—污泥回流工艺,在小试、中试基础上,对原处理工程进行了改造。改造后出水重金属含量稳定。Cu2+、TCr和Ni2+的含量上限值分别小于0.5 mg/L、0.6 mg/L和0.5 mg/L,与改造前相比,改造后PAC和PAM用量可分别节省70%和93%,污泥产生量也会相应减少。加载絮凝—污泥回流工艺可实现电子行业废水重金属达标排放,同时可降低处理成本和污泥产量,具有较好的应用前景。

The heavy metal-containing wastewater from electronic industry is conventionally treated with coagulation-settlement process.However,the conventional coagulation method has the defects of larger dosage of coagulant,more sludge yield,greater impact on fluctuation of water quality,etc.Therefore,a ballasted flocculation-sludge return process is put forward herein for improving the original treatment works on the basis of the relevant lab trail and pilot trail.After the improvement,the heavy metal content is stable,i.e.the upper limit values of the contents of Cu2+,TCr and Ni2+ are less than 0.5 mg/L,0.6 mg/L and 0.5 mg/L respectively and the dosages of PAC and PAM can be saved by 70% and 93% along with corresponding decrease of the sludge yield,if compared with those before the improvement.With the ballasted flocculation-sludge return process,not only the heavy metals in wastewater from electronic industry can be discharged under the relevant standards,but the treatment cost and the sludge yield can also be reduced.Therefore,the process has a better application prospect.