The Research Of Repairing Yangzhou Ancient Canal Sediment By Biological Zeolite Capping

With development of China’s industrialization and urbanization, the problem ofurban river eutrophication is increasing. As an effective measure to control the releaseof pollutants from contaminated sediments, in situ covering method is the researchhotspot of both domestic and foreign. Therefore, this paper took Yangzhou ancientcanal as the object of study, investigated the feasibility of reducing nitrogen load by thecoverage of biozeolite （i.e. zeolite attaching isolated heterotrophic nitrifiers andaerobic denitrifier）, and it aims to study the superiority and efficiency of biozeolitecoverage comparing with zeolite coverage, and the effect and influencing factors ofreducing nitrogen load of Yangzhou ancient canal by biozeolite covers. The mainconclusions are as follows:（1） It is effect to reduce nitrogen load of Yangzhou ancient canal by biozeolitecoverage. Under the condition of covering strength2kg·m-2（thickness of about2mm）,the reduction efficiency of total nitrogen （TN） reach up to60%⁷5%ï¼›while wasincreased by23.48%compared with that of zeolite coverage. This result shows that itis very important for biozeolite attached isolated bacteria to reduce nitrogen load.（2） Control DO in the range of1³mg· L^-1, the highest reduction efficiency ofTN and NH₄⁺-N by biozeolite coverage were73.90%and98.37%respectively, whichhigher than the corresponding record under the condition of anaerobic （20.54%,38.63%） and oxygen （19.62%,46.27%）. This indicated that the optimal DOconcentration was1³mg·L^-1for reducing nitrogen load by biozeolite coverage.（3） The hydraulic disturbance restrained the release of NH₄⁺-N from sediment.When water hydraulic disturbance occurred, the reduction efficiency of TN dropped from67.80%to36.99%under the condition of bio-zeolite coverage. It shows thatwater hydraulic disturbance weaken the ability of reducing nitrogen load by thecoverage with biozeolite.（4） In the system with the coverage by bio-zeolite, the reduction efficiency of TNincreased from60.49%to76.15%when carbon source was increased. This suggestthat less carbon source in the later stage is the major reason of low capacity of cuttingnitrogen load, and sufficient carbon source is good for the process of denitrification.