Experiment And Application Of Removing Manganese From Drinking Water By Potassium Permanganate

This paper summarizes various manganese removal processes and methods at home and abroad,analyzes the theoretical mechanism of oxidative manganese removal by potassium permanganate,and establishes a set of economical and efficient manganese removal process for tap water by potassium permanganate through static coagulation beaker test and theoretical analysis combined with practical engineering practice.Now it has been applied steadily in engineering projects.The mechanism of oxidative manganese removal by potassium permanganate is the oxidation-reduction reaction between potassium permanganate and divalent manganese ion in water.According to the reaction mechanism,the direct or indirect factors affecting the oxidative manganese removal by potassium permanganate are the type of oxidant,the dosage of oxidant,the contact oxidation time,the type of coagulant,the dosage of coagulant,pH and so on.Potassium permanganate?KMnO₄?,sodium hypochlorite?NaClO?,hydrogen peroxide?H₂O₂?and chlorine dioxide?ClO₂?were selected as oxidants to carry out static beaker tests,and their manganese removal effects were investigated.Experiments show that potassium permanganate?KMnO₄?has the best manganese removal effect,so potassium permanganate?KMnO₄?is chosen as the oxidant of the treatment process;The effect of potassium permanganate dosage on manganese removal was investigated.A single factor static beaker test was carried out.The results showed that when the dosage of potassium permanganate was 1.3 times of the theoretical value,it was the most economical and effective;Different pH value and reaction time also have great influence on the manganese removal efficiency by potassium permanganate oxidation.When the pH value of water sample is 7.5 and the reaction time is 10 minutes,the oxidation reaction is basically completed,and the manganese removal rate is over 97%,which is the most economical and effective condition.Manganese dioxide concentration is conducive to the positive reaction,so that the reaction is more thorough.The effects of coagulant types and dosage on the oxidative manganese removal efficiency of potassium permanganate were investigated.The results showed that polyferric sulfate had the best treatment effect when the dosage was 20mg/L,so polyferric sulfate was used as precipitation.Coagulant;through filtration test,the filtration effect of different media was investigated,quartz sand was the best,and quartz sand was selected as the experimental filter material.The potassium permanganate oxidation manganese removal process has been applied in practical engineering and has been put into use for two years.The effluent quality conforms to the Sanitary Standard for Drinking Water?GB5749-2006?,and remains stable.The operation cost is analyzed.The direct treatment cost is 0.13yuan/ton of water.