不同覆盖方式对底泥内源营养盐释放的控制效果

Control effect of different covering patterns on indigenous nutrient release from sediment

通过底泥内源营养盐释放控制室内模拟试验,考察了塑料包被、斜发沸石、方解石、石英砂和硝酸钙5种覆盖材料对底泥氮磷释放效率的影响,系统分析了各自优劣程度,为实际环境中不同污染背景水体选择适宜的控制技术提供科学依据.结果表明:不同覆盖材料对底泥总磷释放的控制效果依次为:塑料包被>硝酸钙>斜发沸石>方解石>石英砂;不同覆盖材料对底泥总氮释放的控制效果依次为:斜发沸石>塑料包被>方解石>石英砂>硝酸钙;不同覆盖材料对底泥硝态氮释放的控制效果依次为:塑料包被>斜发沸石>方解石>石英砂>硝酸钙;不同覆盖材料对底泥铵态氮释放的控制效果依次为:硝酸钙>石英砂>斜发沸石>方解石>塑料包被;温度和底泥内源营养盐释放有对应关系,水样中总磷、总氮和硝态氮浓度会随着温度上升而增加,而铵态氮浓度呈下降趋势.

A laboratory simulation experiment was conducted to study the release of sediment phosphorous and nitrogen under the effects of coating the sediment with plastic, clinoptilolite, calcite, quartz sand, and calcium nitrate, aimed to provide scientific basis and technical support to control the sediment nutrient release under the background of water environment pollution by different con- centrations of nitrogen and phosphorus. The control efficacy of test coating materials for sediment total phosphorous release was in the order of plastic 〉 calcium nitrate 〉 clinoptilolite 〉 calcite 〉 quartz sand, and that for sediment total nitrogen release was in the order of clinoptilolite 〉 plastic 〉 calcite 〉 quartz sand 〉 calcium nitrate. As for the release of sediment NO3--N, the control efficacy of test coating materials was calcium nitrate 〉 quartz sand 〉 clinoptilolite 〉 calcite 〉 plastic coating; whereas for the release of sediment NH4 ＋-N, the sequence was calcium nitrate 〉 plastic coating 〉 clinoptilolite 〉 calcite 〉 quartz sand. Water temperature had definite relativity to the sediment nutrient release. With the increase of water temperature, the concentrations of water total phosphorous and nitrogen and NO3 -N increased, while the concentration of water NH4 -N presented a declining trend.