木薯淀粉废水混凝预处理试验

在对木薯淀粉生产过程中产生的2种主要废水进行混凝试验的研究中,探讨了pH值、混凝剂的种类及混凝剂、助凝剂的投加量对混凝反应的影响.试验表明,2种废水混凝反应最佳pH值范围均为7.0～7.5.一次废水最佳混凝剂为聚铁(PFS),COD去除率约45%,剩余浊度仅为500度;二次废水最佳混凝剂为聚铝(PAC),COD去除率最高可达62%,剩余浊度仅为210度.混凝过程中的沉淀物含有大量的蛋白质和氨基酸,可回收做饲料添加剂.广西年排放淀粉废水约2000万m3,回收的沉淀物按1 000元/t计,每年可获得约3 200万元的产值.

Experiment of pretreating cassava starch wastewater with coagulation process

Two main kinds of wastewater from cassava starch production were studied with coagulation experiment, the effects of pH value, variety of coagulant, dosage of coagulant and flocculant on the coagualtion reaction were discussed. The results showed that, the optimal pH value for the wastewater was 7.0 - 7.5. To the first separate wastewater, cogulation reaction of the two kinds of the optimal cogulant was PFS, the removal rate of COD reached 45%, and the degree of residual turbidity was only about 500. To the second separate wastewater, the optimal cogulant was PAC, the removal rate of COD reached 62% and the degree of residual turbidity was only 210. The deposit during the cogulation process contained large amount of proteid and aminophenol, which could be reclaimed and used as feed additive. The volume of cassava starch wastewater was 20 million m^3 a year in Guangxi province, the reclaimed deposit cost 1,000 yuan/t, and the production value could be about 32 million yuan a year.