Research on cellar rainwater of northwest region villages and small towns enhanced coagulation by potassium permanganate combined with powdered activated carbon

Abstract

According to cellar rainwater characteristics, the rainwater contains turbidity, lower temperature and micropolluted in northwest region villages and small towns. The result is not fine by adopting the conventional coagulation. The effect of three ways regarding enhanced coagulation was studied. The three methods were permanganate pre-oxidation alone, powder activated carbon (PAC) added alone and KMnO4 and PAC combination. Static experiments of three methods were carried out. The results showed: KMnO4 and PAC combination had the best effect of enhanced coagulation. Under the best conditions in conventional coagulation, when the optimal dosage of KMnO4 was 2mg·L-1, pre-oxidation time was 15min, while the optimal dosage of PAC was 10mg·L-1 and was added after 3min of coagulant dosing, the removal rate of cistern water turbidity and CODMn could be 98.5% and 56.6% after enhancing coagulation. The experiment also proved that there were synergies between them. This approach was more efficient to treat with cistern water of northwest region villages and small towns.