厌氧条件下深谷型湖泊底泥覆盖效果研究

THE EFFECT OF COVERING ON SEDIMENT IN A CANYON TYPE LAKE UNDER THE ANAEROBIC CONDITION

为有效控制深谷型湖泊内源污染,构建底泥活性覆盖系统,以脱碱赤泥为主料,粉煤灰、黏土和Ca CO3为辅料,制作了不同配比的底泥覆盖材料,并评价其在厌氧条件下对湖泊内源污染物的控制效果。结果表明:底泥覆盖后上覆水体水质总体趋于稳定,DO水平能够得到改善,TP和COD的释放受到抑制,对NH3-N虽有一定控制作用但短期效果不理想;3种材料覆盖后,上覆水体中均低检出或未检出Cu、Pb、Zn、Cr、Cd,Fe、Mn、Ca、Mg的含量也较对照组低,削弱了金属元素的释放迁移;结合底泥内源污染物的控制效果和上覆水体水质的稳定性两方面因素,3种材料中,材料2(配料为赤泥38.9%,黏土14.4%,粉煤灰38.9%,Ca CO37.8%)最适于深谷型湖泊底泥覆盖。该覆盖方法原料获取方便、材料制作简单、经济成本低廉、操作方法简易、污染控制效果优良,可用于深谷型湖泊底泥原位控制。

Active sediment cover system was constructed for the effective control of lake sediment pollution. Several covering materials were prepared according to different proportion of red mud,fly ash,clay and Ca CO3 to investigate the effect on control sediment pollutant. The red mud after de-alkalization was the main material. Results showed that the coverage can stabilize the quality of the overlying water,improve the concentration of DO,and limit the COD and TP content. However,the control effect of NH3-N is weak in short term. Additionally,the coverage could decrease heavy metals（Cu,Pb,Zn,Cr,Cd,Fe,Mn,Ca,Mg） re-released from sediment to overlying water. Considering two aspects of the control effect on endogenous contaminants and stability of the overlying water quality,material Ⅱ（red mud 38. 9%,clay 14. 4%,fly ash 38. 9%,Ca CO37. 8%） is most suitable for covering deep lake sediment due to obtaining raw materials conveniently,making simple,low economic cost,simple operation and good effect.