Treatment of the wastewater containing low-level 241Am using flocculation-microfiltration process

Abstract

This paper studies the treatment of low-level radioactive wastewater containing 241Am by a combined flocculation-microfiltration (FMF) process. The average concentration ratio of the treated wastewater to the discharged sludge was 189.8 in the cold test. After operating for 4 months, the fouled membrane was cleaned and cleaning effects of physical and chemical methods were compared. In the hot test, the pH was adjusted with nitric acid and 20mg/l potassium permanganate was added to remove surfactants from the feed during pretreatment. The pretreated wastewater was pumped to the membrane reactor, where the pH was adjusted to above 8 and the dosage of Fe3+ was 30mg/l. The mixed liquor was then filtered through the submerged microfiltration (MF) membrane. When the radioactivity of 241Am in the feed was 809.2Bq/l, the effluent was below 1.0Bq/l. The removal of 241Am was higher than 99.9%. The decontamination factor (DF) is more than 1651.4. The results showed that the FMF process has significant potential in treating low-level radioactive wastewater containing 241Am.