植物净化床去除营养物规律研究

RULES OF REMOVING NUTRIMENTS IN PLANTING PURIFY BED

对植物净化床进出水及床体内部水样进行水质监测,分析植物净化床去除氮磷的途径,研究植物净化床内部DO与营养盐的分布和去除规律。试验结果表明,硝化/反硝化是脱氮主要途径,占TN去除率的46%～55%,吸附沉淀是磷去除主要途径,占TP去除率的54%～65%;植物净化床内ORP(氧化还原电位)均为负值,床体表层为弱还原区、中层为中等还原区、底层为强还原区;植物净化床中除NO3--N外,其他营养物质浓度均沿程逐渐降低,其中CODMn、NH4+-N、TP在第一级中去除率分别达到71%、57%、53%;竖直方向上,由上到下NH4+-N含量逐渐增加,CODMn、NO3--N含量逐渐降低,TN含量下层低于中上层,TP含量先降低后升高,植物净化床上层中有机物的去除率较高,达到总CODMn去除率的65%,CODMn和TP主要在植物净化床的中上层得到去除,TN和NO3--N主要在净化床下层得到去除。

The approach of removing nitrogen and phosphorus were analyzed by testing the inflow, outflow and water inside planting purify beds to investigate the situation of dissolved oxygen（DO） and rules of removing nutriments. The experiment results showed that： nitrification and denitrification were main approaches of removing nitrogen, accounting for 46%-55% of the removal ratio of total nitrogen, and adsorption and settling were the main approaches of removing phosphorus, accounting for 54%-65% of the removal ratio of total phosphorus. The values of oxidation-reduction potential in planting purify beds were all negative. The surface layers of planting purify beds were weak reduction area, the middle layers were middle reduction area and the bottoms were strong reduction area. The concentration of total nitrogen（TN）, total phosphorus （TP）, chemical oxygen demand （CODMn） and ammonia-nitrogen （NH4^＋-N） all reduced along the flow, and the removal rates of chemical oxygen demand, ammonia-nitrogen and total phosphorus were 71%, 57% and 53% in the first stage of planting purify beds, respectively. From surface to bottom, the concentration of ammonia-nitrogen increased gradually, but the concentration of chemical oxygen demand and nitrate-nitrogen （NO3^--N） decreased gradually. The concentration of total nitrogen at bottom was lower than that at surface in planting purify beds, and the concentration of total phosphorus decreased firstly then increased along vertical direction. The removal rates of chemical oxygen demand in surface and middle layer of planting purify beds were about 65%, which is higher than that in bottom. Chemical oxygen demand and total phosphorus were mostly removed at surface and middle layer of planting purify beds, and total nitrogen and ammonia-nitrogen were mostly removed at bottom of planting purify beds.