介质筛护岸的水质净化功能与机理

Function and mechanism of the media sieve embankment on water purification

以桂林桃花江介质筛护岸工程为依托,对介质筛护岸的水质净化功能进行了试验研究.结果表明,介质筛护岸两侧水位波动促进了生物地球化学反应的发生.介质筛护岸对COD、NH4+-N和TN的平均去除率分别为76.5%、95%和81%.介质层内的COD浓度逐层降低,在距离岸边2.5m左右的沸石强化层中,其浓度接近5mg·L-1;在介质筛的第5、6层内NH4+-N的浓度基本稳定在0.3mg·L-1.沸石层对NH4+-N吸附的有效厚度为10cm,能够满足水质净化的目的.

Water purification experiments were conducted in a media-sieve embankment （MSE） with zeolite barrier, in the Taohuajiang river, in the city of Guilin. Fluctuation of the water table on both sides of the MSE promoted water purification by way of a biogeochemical process. Average removal rates of COD, NH4^＋ -N and TN in the MSE were 76.5% , 95% and 81% , respectively. The concentration of COD gradually decreased from outside to inside in the MSE. In the tested zeolite barrier, about 2.5 m away from the bank the concentration of COD was close to 5 mg·L^-1 . Concentrations of NH4^＋ -N in the fifth and sixth layers were stabilized at 0.3 mg·L^-1. An effective thickness （ 10 cm） of the zeolite barrier could adsorb NH4^＋ -N completely and meet the requirement of river-water purification.