Development And Application Of Oxygen Restoration Preparation On Polluted Water Body Sediment

With changing environmental conditions, pollutants in sediment would be released again and contaminated the overlying water. A new kind of oxygen restoration preparation was developed and the effects of various mixture ratios on the oxygen releasing efficiency of the preparation were investigated, including the mass ratio of calcium peroxide to activated carbon, the mesh number of activated carbon, etc. Under initial anaerobic condition, experiments were designed to simulate the process of phosphorus release from the sediment. Based on the average removal rate of inorganic phosphorus, the optimal mixture ratio of the preparation was determined as following:the mass ratio of calcium peroxide to activated carbon was 3 to 2, and equal mass of activated carbon with particles size of 20-40 mesh and smaller than 60 mesh was mixed.In static model of water body, with the dosing of the developed preparation at the sediment-water interface, in situ bio-remediation of the simulation sediment contaminated by two concentration levels of naphthalene was studied under initial anaerobic condition, and the eutrophication control of the water body was also investigated. The results indicated that when naphthalene content in sediment was higher than 9.5μg/gwet mud, sediment microbial physiological activity began to be restrained. For the sediment contaminated with lower concentration of naphthalene (case A), the naphthalene biodegradation rate constant of remediation sample A was greater than that for the control group and slightly higher than that for the blank group. For the sediment contaminated with higher concentration of naphthalene (case B), the naphthalene biodegradation rate constant of remediation sample B was greater than that for the control group and close to that for the blank group. For the overlying water, the index of phosphorus, nitrogen and COD also declined evidently, which had obvious effect on eutrophication control. The kinetic studies indicated that the processes of naphthalene biodegradation in the water body and its removal from sediment both followed the first-order kinetics. And desorption process of naphthalene from sediment to overlying water was verified.