不同营养条件对薏苡人工湿地去除Cr(Ⅵ)的影响

Effects of different nutritient conditions on the removal of Cr(Ⅵ)by Coix aquatica Roxb.construced wetland

为研究不同营养水平下薏苡人工湿地对Cr(Ⅵ)的净化与形态转变化的影响,以生活污水(W)、1/2(体积比)Hoagland营养液(Y)、1/2 Hoagland营养液+生活污水(Y+W)为灌溉水源,构建微型模拟垂直流薏苡人工湿地,采取间歇进水方式,进水分别以0、10、30 mg/L左右Cr(Ⅵ)(以K 2Cr 2O 7形式加入)进行处理。结果表明:(1)根、茎、叶中总铬均随处理时间的延长和Cr(Ⅵ)浓度的提高而提高;不同器官之间相比较,总铬依次为根>叶>茎。(2)在不同营养条件下,基质中可交换态、铁锰氧化物结合态、有机物结合态、残渣态铬含量均随着Cr(Ⅵ)浓度的增加而提高,而碳酸盐结合态铬则先升高后降低。(3)Y处理出水Cr(Ⅵ)较高,W、(Y+W)处理均能提高人工湿地对含铬污水的处理效果。

In order to study the effect of Coix aquatica Roxb.construced wetland on Cr(Ⅵ)purification and morphological transformation under different nutrient levels,the micro simulated vertical flow constructed wetland of Coix aquatica Roxb.was constructed using domestic sewage(W),1/2(volume ratio)Hoagland nutrient solution(Y)and 1/2 Hoagland nutrient solution+domestic sewage(Y+W)as irrigation water sources.Intermittent water inflow was adopted.The influent water was treated with 0,10 and 30 mg/L Cr(Ⅵ)in the form of K 2Cr 2O 7.Results showed that:(1)total chromium in roots,stems and leaves increased with the increase of Cr(Ⅵ)concentration and treatment time.Compared with different organs,the order of total chromium was root>leaf>stem.(2)Under different nutrient conditions,the contents of exchangeable chromium,iron manganese oxide bound chromium,organic bound chromium and residual chromium increased with the increase of Cr(Ⅵ),while carbonate bound chromium increased first and then decreased.(3)The Cr(Ⅵ)in the effluent of Y treatment was higher.W and(Y+W)treatment could improve the treatment effect of constructed wetland for chromium containing wastewater.