Zupancic Marija, Bukovec Peter, Milacic Radmila, Scancar Janez
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia.
Waste Manag. 2006;26(12):1392-9. doi: 10.1016/j.wasman.2005.12.007. Epub 2006 Feb 20.
The leachability of zinc (Zn) and nickel (Ni) was investigated in various soil types amended with sewage sludge and sewage sludge treated with hydroxyapatite. Sandy, clay and peat soils were investigated. For leachability tests, plastic columns (diameter 9 cm, height 50 cm) were filled with moist samples up to a height of 25 cm. Sewage sludge (1 kg) was mixed with 4.6 kg of clay and sandy soils and with 6.7 kg of peat soil. For sewage sludge mixtures treated with hydroxyapatite, 0.5 kg of the hydroxyapatite was added to 1 kg of the sewage sludge. Neutral (pH 7) and acid precipitation (pH 3.5) were applied. Acid precipitation was prepared from concentrated HNO(3), H(2)SO(4) and fresh doubly distilled water. The amount of precipitation corresponded to the average annual precipitation for the city of Ljubljana, Slovenia. It was divided into eight equal portions and applied sequentially on the top of the columns. The results indicated that the leachabilities of Zn in sewage sludge amended peat and clay soils were low (below 0.3% of total Zn content) and of Ni in sewage sludge amended sandy, clay and peat soil below 1.9% of total Ni content. In sewage sludge amended sandy soil, the leachability of Zn was higher (11% of Zn content). The pH of precipitation had no influence on the leachability of either metal. Treatment of sewage sludge with hydroxyapatite efficiently reduced the leachability of Zn in sewage sludge amended sandy soil (from 11% to 0.2% of total Zn content). In clay and peat sewage sludge amended soils, soil characteristics rather than hydroxyapatite treatment dominate Zn mobility.
研究了用污水污泥和经羟基磷灰石处理的污水污泥改良的各种土壤类型中锌（Zn）和镍（Ni）的淋溶性。研究了砂土、粘土和泥炭土。对于淋溶性测试，将塑料柱（直径9厘米，高50厘米）装满潮湿样品至25厘米高度。将1千克污水污泥与4.6千克粘土和砂土以及6.7千克泥炭土混合。对于用羟基磷灰石处理的污水污泥混合物，向1千克污水污泥中添加0.5千克羟基磷灰石。施加中性（pH 7）和酸性降水（pH 3.5）。酸性降水由浓硝酸（HNO₃）、硫酸（H₂SO₄）和新鲜的双蒸水配制而成。降水量相当于斯洛文尼亚卢布尔雅那市的年均降水量。将其分成八等份并依次施加在柱顶。结果表明，在经污水污泥改良的泥炭土和粘土中，锌的淋溶性较低（低于锌总含量的0.3%），在经污水污泥改良的砂土、粘土和泥炭土中，镍的淋溶性低于镍总含量的1.9%。在经污水污泥改良的砂土中，锌的淋溶性较高（锌含量的11%）。降水的pH值对两种金属的淋溶性均无影响。用羟基磷灰石处理污水污泥可有效降低经污水污泥改良的砂土中锌的淋溶性（从锌总含量的11%降至0.2%）。在经污水污泥改良的粘土和泥炭土中，土壤特性而非羟基磷灰石处理主导着锌的迁移性。
