治理感潮河道黑臭的底泥原位修复技术研究

In-situ Sediment Remediation Technology for Control of Black and Odorous Water in Tidal River

选择典型的珠江流域重污染感潮河道——广州市荔湾区郭村涌为研究对象,结合河道感潮特性,在退潮后的最低水位时采用底泥曝气并投加TRSS稳定剂来消除河道黑臭,以利于河道生态系统的恢复。研究结果表明:底泥曝气可有效氧化底泥中的硫化物,运行一个月后对其去除率达到了86.3%～92.1%,臭味基本被消除;底泥经投加TRSS进行稳定化处理后,Cu、Zn、Cr、Cd等重金属的释放量降低了79.5%～87.2%,且形态更加稳定,经底泥毒性鉴别其浸出量分别降低了66.2%、81.5%、82.2%和78.6%,均低于危险废物毒性鉴别标准值,同时还使磷的释放量降低了约90%;停止投药两个月后,底泥中硫化物的含量稳定在0.035 g/kg以下;维持微碱性、好氧条件(pH≈8,DO>2 mg/L),可使表层底泥由黑色变成亮褐色,上覆水体水质稳定,黑臭基本消除。

Taking Guocun River in Liwan District of Guangzhou City, a typical heavily polluted urban tidal river in Zhujiang Delta Area as research object, based on the tidal characteristics of the river, the black and odorous water was treated by aeration and oxidation of the sediment and addition of TRSS stabilizing agent in the period of low tide to help the restoration of the river ecosystem. The results show that： （1） By sediment aeration, about 86.3% to 92.1% sulfide in sediment is oxidized in 30 days, and the odors disappear. （2） Cu, Zn, Cr and Cd in sediment become more stable after stabilization treatment, and their release amounts are reduced by 79.5% to 87.2% , furthermore, their extraction amounts after identification for extraction procedure toxicity are reduced by 66.2% , 81.5% , 82.2% and 78.6% , respectively, which are much lower than the values of identification standard for hazardous waste. At the same time, about 90% of TP in treated sediment is stabilized. （3） Under alkalescence and oxidation state （pH ≈8, DO 〉 2 mg/L）, the overlying water quality is improved, and the colors of surface sediment are turned from black to light brown, in addition, concentration of sulfide in sediment is kept below 0.035 g/kg for over two months after stopping addition of stabilizing agents, which means that the black andodorous water is treated well.