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| Effects of sludge dredging on black bloom: a case study of Bafang port and Lujiang port of Taihu Lake |
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Abstract In order to estimate the effects of dredging on the prevention and control of black bloom, four intact sediment cores had been sampled from dredged and un-dredged areas of Bafang port and Lujiang port to simulation the occurrence and regression of algae-caused black bloom with Y-shape apparatus. Results showed that dredging has a good effect on prevention the degree of algae-caused black bloom. The color of water in dredged treatment group was lighter than the control, and the occurrence time of black bloom in dredged sites of Bafang port and Lujiang port was delayed 6days and 2days, respectively. The concentrations of NH4+-N, PO43--P in overlying water of dredged treatment group of Bafang port and Lujiang port were only 40%, 77.1%, 41.4% and 78.1% of control treatment, and the concentrations of Fe2+ and S2- in overlying water of dredged treatment group were higher than control. The concentrations of Fe2+ in sediments of dredged sites of Bafang port and Lujiang port were 78.1% and 76.4% of control sites, and the concentration of Acid Volatile sulphide (AVS) in dredged site of Lujiang port was 1.36times than control. Vertical distribution characteristics of Fe2+ and AVS in sediment were not observed in this experiment. Overall, dredging can effectively prevent the occurrence of black bloom.
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Received: 04 November 2013
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