Effect of Porous Streambed on Purifying Polluted Water in Eco-irrigation District

摘要

Porous streambed was induced to purify the polluted water in eco-irrigation district.The purification effects of porous streambed with different types of material were experimentally studied in laboratory.The tested materials were gravel and macadam.The experimental results showed that both types ot material gave high purification effects at startup stage,however,macadam gave better results than gravel.The removal rates of TN,TP,CODMn,and NH4+ in macadam channel were 1.8,1.7,1.7 and 1.6 times respectively than those in gravel channel.Thus,macadam was an ideal choice to purify polluted water.Furthermore,the experimental results of macadam channel at the established stage of micro-ecosystem showed the removal rate of TN increased remarkably,while the removal rate of NH4+ was stable.On the other hand,the removal rates of TP and CODMn.decreased comparing to that during the startup stage.The main mechanism of pollutants removal at the startup stage was the physical adsorption process,and that at the established stage of microecosystem was the biochemical degradation process.