Green land is important carrier in cities. We investigated the effects of soil permeability improvement and purification of pollutants under different matrix composition amendments in Xixian New Area, Shaanxi Province. Six materials, including biochar, vermiculite, perlite, compost, polyacrylamide (PAM) and coir, were mixed with basic materials that were composed of soil and sand (volume ratio of 4:4), and then incubated for 30 days. We analyzed bulk density, saturated hydraulic conductivity, saturated moisture, and total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), copper (Cu), zinc (Zn), cadmium (Cd) concentrations in pollutants. For biochar and compost with volume ratio of 0.5:1.5 (1) and 1:1 (2), 1%PAM application had the best effect on soil permeability (including bulk density, saturated hydraulic conductivity, and saturated moisture). The effect purification of TN and COD was better under the condition of biochar and compost (1) with 0.5% PAM amendment than that with 1% PAM amendment. Under biochar and compost (1) with 1%PAM treatment, the adsorption rate of Zn, Cd, Cu was 99.9%, 99.7%, and 97.2%, respectively. In general, biochar and compost (volume ratio of 0.5:1.5) with 1% PAM could be recommended as the media of the sponge city green land in Xixian New Area.
绿地土壤是城市的重要载体。为探讨不同物料配比对西咸新区土壤渗透性改良及污染物净化效果的影响,本试验将生物质炭、蛭石、珍珠岩、堆肥、聚丙烯酰胺(PAM)、椰糠等6种物料分别与体积比为4∶4的土沙混匀,室内培养30 d,分析了介质容重、饱和导水率、饱和含水量及污染物总氮(TN)、总磷(TP)、化学需氧量(COD)、铜(Cu)、锌(Zn)、镉(Cd)浓度。结果表明: 体积比分别为0.5∶1.5(Ⅰ)和1∶1(Ⅱ)的生物质炭∶堆肥添加1%PAM配比对介质渗透性(包括容重、饱和导水率、饱和含水量)的改良效果最好;I添加0.5%PAM配比对TN、COD的净化效果优于添加1%PAM处理,但后者对Zn、Cd、Cu的吸附率分别达99.9%、99.7%、97.2%。综合考虑,体积比为0.5∶1.5的生物质炭∶堆肥添加1%PAM可作为西咸新区城市绿地土壤换填介质。.
Keywords: biochar; compost; pollution reduction; polyacrylamide (PAM); soil permeability improvement; urban green soil.