A new method of inhibiting pollutant release from source water reservoir sediment by adding chemical stabilization agents combined with water-lifting aerator

Source water reservoirs easily become thermally and dynamically stratified. Internal pollution released from reservoir sediments is the main cause of water quality problems. To mitigate the internal pollution more effectively, a new method, which combined chemical stabilization with water lifting aerator (WLA) technology, was proposed and its efficiency in inhibiting pollutant release was studied by controlled sediment-water interface experiments. The results showed that this new method can inhibit pollutant release from sediment effectively. The values of mean efficiency (E) in different reactors 2#-5# (1# with no agent, 2# 10 mg/L polymeric aluminum chloride (PAC) was added, 3# 20 mg/L PAC was added, 4# 30 mg/L PAC was added, 5# 20 mg/L PAC and 0.2 mg/L palyacrylamide (PAM) were added) for PO43- were 35.0%, 43.9%, 50.4% and 63.6%, respectively. This showed that the higher the PAC concentration was, the better the inhibiting efficiency was, and PAM addition strengthened the inhibiting efficiency significantly. For Fe2+, the corresponding values of E for the reactors 2#-5# were 22.9%, 47.2%, 34.3% and 46.2%, respectively. The inhibiting effect of PAC and PAM on Mn release remained positive for a relatively short time, about 10 days, and was not so effective as for PO43- and Fe2+. The average efficiencies in inhibiting the release of UV254 were 35.3%, 25.9%, 35.5%, 38.9% and 39.5% for reactors 2#-5#, respectively. The inhibiting mechanisms of the agents for different pollutants varied among the conditions and should be studied further.