[Influencing factors of calcite active barrier system to control phosphorus release from sediments]

Influencing factors of calcite active barrier system to control phosphorus release from sediments were researched, including barrier thickness, Ca2+ of overlying water, temperature, calcite's grain size and artificial aeration. The results show that the calcite barrier can effectively control phosphorus release from sediments under anaerobic conditions, and its efficiency was influenced by barrier thickness, Ca2+ concentration of overlying water, temperature, calcite's grain size and artificial aeration. The efficiency of calcite barrier to control phosphorus release from sediments will increase with the increment of Ca2+ concentration of overlying water and barrier thickness. Application of 12.7 kg/m2 calcite active barrier system resulted in 56% reduction of phosphorus flux from sediment for 72 days; however 99% reduction was obtained by 38.2 kg/m2 calcite active barrier system. When the Ca2+ concentration of overlying water increased from 1 mmol/L to 5 mmol/L, the phosphorus concentration was reduced by about 36% in the 72nd day. In comparison to low temperature, high temperature was disbennifit to control phosphorus release from sediments by a thin calcite barrier. The smaller the grain sizes of calcite, the more efficient the calcite barrier. The ammonia and phosphorus release rate from sediments under calcite barrier will be decreased by aeration.