人工湿地不同基质对城市生活污水净化效果研究

Study on the Purification Effect of Different Substrates in Constructed Wetland on Urban Domestic Sewage

选取果壳炭、炉渣、陶粒和沸石4种填料,在不同水力停留(12、24、48和72 h)的条件下,进行人工湿地模拟净化生活污水试验。结果表明,4种基质中果壳炭和炉渣对出水pH的影响较大,果壳炭在不同水力停留时段出水pH(8.2~8.6)较进水(pH=7.6)高,炉渣在水力停留12和48 h增加了出水pH(分别为8.05和8.20)。4种基质在不同水力停留时段对COD和BOD_(5)均表现出了较好的处理效果,去除率分别达到了57.08%~81.85%和72.25%~94.16%,尤其是对BOD_(5)基本随水力停留时间的增加而增加(水力停留72 h时果壳炭除外)。在不同水力停留条件下,各基质对总氮的去除效果均表现为果壳炭>陶粒>沸石>炉渣,果壳炭和陶粒以水力停留72 h去除效果最佳,而沸石和炉渣在水力停留前期(12和24 h)的处理效果优于后期(48和72 h);各基质对氨氮的去除效果均表现为果壳炭>陶粒>炉渣>沸石,且随着水力停留时间的延长而增加;吸附总磷效果最好的是炉渣,对总磷的去除率均显著优于陶粒和沸石(P<0.05),而果壳炭却表现出少量的释磷现象。

Four kinds of fillers(fruit shell carbon,slag,ceramsite and zeolite)were selected to simulate the purification of domestic sewage by constructed wetland under different hydraulic retention conditions(12,24,48 and 72 h).The results showed that the fruit shell carbon and slag in the four substrates had a great influence on the pH of effluent.The pH of outfall(8.2-8.6)was higher than that of inflow(pH=7.6)in different hydraulic retention periods for fruit shell carbon system.The slag system increased the pH of outlet water(8.05 and 8.20 respectively)after hydraulic retention for 12 and 48 h.The four substrates showed good treatment effects on COD and BOD_(5)during different hydraulic re-tention periods,and the removal rates of BOD_(5)were 57.08%-81.85%and 72.25%-94.16%,respectively.Especially,BOD_(5)increased with hydraulic retention time(except for fruit shell carbon when hydraulic retention time was 72 h).Under different hydraulic retention conditions,the removal effects of total nitrogen for different substrates were as follows:fruit shell carbon>ceramsite>zeolite>slag.The removal efficiencis of fruit shell carbon and ceramsite were the best under 72 h hydraulic retention.But the treatment effect of zeolite and slag in the early period of hydraulic retention(12 and 24 h)was better than that in the later period(48h and 72 h).The removal effect of ammonia nitrogen by different substrates was as follows:fruit shell carbon>ceramsite>slag>zeolite,and it increased with the extension of hydraulic residence time.The slag had the best effect of adsorbing total phosphorus,and the removal rate of total phosphorus was significantly better than that of ceramsite and zeolite(P<0.05),but the fruit shell carbon showed a small amount of P release.