Centre National des Recherches en Science des Matériaux, Borj Cedria Techno-Park, B.P. 95-2050, Hammam Lif, Tunis, Tunisia.
Waste Manag. 2013 Jan;33(1):60-6. doi: 10.1016/j.wasman.2012.08.012. Epub 2012 Sep 11.
Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.
研究了来自突尼斯的三种天然粘性土，以评估它们是否适合用作酸性废物处置场的衬垫。本文研究了矿物成分和机械压实对三种不同土壤水力传导率以及氟离子和磷酸根去除的影响。这三种天然土壤的水力传导率分别为 8.5×10(-10)、2.08×10(-9)和 6.8×10(-10)m/s（土壤-1、土壤-2 和土壤-3）。为了获得三种不同的湿密度（1850、1950 和 2050kg/m(3))，对土壤试件进行了不同压实应变下的压实。在此条件下，所有土壤的水力传导率（k）均随样品密度的增加而降低。使用酸性废水（pH=2.7，含氟离子和磷酸根离子）进行长期（>200 天）水力传导率测试的结果表明，只有天然土壤-1 和土壤-2 的 k 值随时间降低。然而，在水力传导率测试 60 天和 20 天后，分别压缩至两个最高密度（1950 和 2050kg/m(3))的土壤-2 试件出现了裂缝。这种损坏是由于膨胀引起的内部应力持续增加以及侵蚀性废水的影响造成的。对阴离子的分析表明，氟离子的保留率高于磷酸根离子，并且土壤-1 具有最高的吸附能力。
