Laboratoire Production, Amélioration Et Protection Des Végétaux Et Des Denrées Alimentaires (LPAPVDA), Université Mouloud Mammeri, BP 17 RP, 15000, Tizi Ouzou, Algeria.
Université de Toulon, Aix Marseille Univ, CNRS, IM2NP, Cedex 9, 83041, Toulon, France.
Environ Sci Pollut Res Int. 2022 Oct;29(46):70396-70407. doi: 10.1007/s11356-022-20868-w. Epub 2022 May 19.
The agricultural spreading of dehydrated sewage sludge from urban sewage treatment plants is economically profitable provided that the soil agronomic quality and the absence of contamination, in particular of heavy metals, are maintained. We evaluated the variability of sludge between five treatment plants in northern Algeria. We determined parameters that account for their agronomic quality and total content of Ag, Cd, Co, Cr, Cu, Ni, Pb, Ti and Zn. The speciation of metals, which determines their bioavailability, was characterized by sequential extraction into five fractions: easily exchangeable, acid-soluble, bound to carbonates and Fe-sulphides, bound to Fe-Mn oxides, bound to organic matter or sulphides, residual. All the sludges analysed showed satisfactory properties for plant growth. High total Ni contents for three of the sludges indicated that they were not landfillable under French or Chinese regulations. Ni, however, was contained in poorly bioavailable fractions and therefore presented a low risk to soils. In contrast, the total Cu was lower than the regulatory limit values, but mainly contained in very bioavailable fractions whose accumulation over time could reach toxic levels for plants over a period of 3 to 11 years depending on the sludges. These results showed that regulations are not adapted and must take into account the bioavailability with regard to the characteristics of the soils on which to spread. The speciation of metals in the sludge has also, on the one hand, made it possible to identify the zone of the sewerage network in which the sources of contamination must be sought and, on the other hand, has given indications on the possible nature of these sources.
只要保持土壤农艺质量和无污染（尤其是重金属污染），从城市污水处理厂农用脱水污泥是具有经济效益的。我们评估了阿尔及利亚北部五个污水处理厂之间的污泥差异。我们测定了反映其农艺质量和 Ag、Cd、Co、Cr、Cu、Ni、Pb、Ti 和 Zn 总量的参数。金属形态决定了其生物利用度，通过连续提取五种金属形态进行特征描述：可交换态、酸可提取态、碳酸盐和硫化物结合态、Fe-Mn 氧化物结合态、有机物或硫化物结合态和残渣态。所有分析的污泥均显示出对植物生长良好的特性。其中三个污泥的总 Ni 含量较高，表明它们不符合法国或中国的填埋规定。然而，Ni 主要存在于生物利用度较差的形态中，因此对土壤的风险较低。相比之下，总 Cu 含量低于法规限值，但主要存在于生物利用度非常高的形态中，这些形态的积累可能会在 3 至 11 年内达到对植物的毒性水平，具体取决于污泥。这些结果表明，法规没有适应，必须考虑到与要施撒的土壤特性有关的生物利用度。污泥中金属的形态还一方面能够确定污水管网中必须寻找污染来源的区域，另一方面提供了这些来源可能性质的线索。
