垂直流人工湿地有机质含量分布特征

利用3种复合基质(沸石+泥炭+红壤、河砂+泥炭+红壤、蛭石+泥炭+红壤,体积比均为18∶1∶1)构建模拟垂直流人工湿地处理人工合成污水,分析基质灭菌与接种污水等情况下,不同基质层w(OM)(OM为有机质)的分布特征. 结果表明:3种复合基质初始w(OM)依次为1.011、6.654和15.896 g/kg,存在显著差异(P<0.01). 复合基质2经灭菌后w(OM)下降26.77%,说明河砂微生物活性最高. 基质灭菌和接种3%污水对湿地w(OM)分布的影响均比较显著(P<0.05),主要是改变了表层的w(OM). 湿地运行45 d后,w(OM)沿基质深度增加明显,并且分布差异显著(P<0.01),OM主要分布于表层；其中复合基质3不灭菌+不接种污水湿地表层的w(OM)高达42.008 g/kg,运行90 d后增至44.228 g/kg,说明蛭石的吸附作用最强. 吸附和微生物作用对复合基质3湿地表层OM积累的贡献大小表现为吸附作用>基质微生物作用>接种污水微生物作用. 

Characterization of Organic Matter Content Distribution in Vertical Flow Constructed Wetland

Three compound substrates (zeolite+peat+red soil, river sand+peat+red soil, and vermiculite+peat+red soil, all with ratios of 18∶1∶1) were used to construct simulated vertical flow constructed wetlands (VFCWs) for synthetic sewage treatment. Organic matter (OM) content distributions from different matrix layers were analyzed under the conditions of sterilized substrate and inoculated microbes to the sewage. The results indicated that there were significant differences (P<0.01) in the original OM content of the three compound substrates, which were 1.011,6.654 and 15.896 g/kg respectively. The river sand had the highest microbial activity value because OM content of compound substrate two decreased 26.77% after sterilization. There were significant differences (P<0.05) in OM content distribution in the VFCWs under the conditions of sterilized substrate and inoculated 3% microbes to the sewage, which mainly occurred at the surface of the VFCWs. The OM content was significantly different among different matrix layers (P<0.01) and mainly distributed on the surface of the top layer after 45 days. The VFCWs filled with compound substrate three (vermiculite+peat+red) had the highest OM contents on the surface of the top layer. The OM contents reached 42.008 g/kg after 45 days and increased to 44.228 g/kg after 90 days without sterilized substrate and inoculated microbes to the sewage. Therefore, vermiculite had the highest adsorption ability. In addition, different actions contributed to the OM accumulation, ranged as:substrate adsorption>substrate microbial action>inoculated microbial action.