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Advisor(s)
Abstract(s)
Overexploitation of resources makes the reutilization of waste a focal topic of modern
society, and the question of the kind of wastes that can be used is continuously raised. Sewage sludge
(SS) is derived from the wastewater treatment plants, considered important underused biomass, and
can be used as a biofertilizer when properly stabilized due to the high content of inorganic matter,
nitrate, and phosphorus. However, a wide range of pollutants can be present in these biosolids,
limiting or prohibiting their use as biofertilizer, depending on the type and origin of industrial waste
and household products. Long-term applications of these biosolids could substantially increase the
concentration of contaminants, causing detrimental effects on the environment and induce hyper accumulation or phytotoxicity in the produced crops. In this work, some critical parameters for
soils and SS agronomic use, such as organic matter, nitrogen, phosphorous, and potassium (NPK),
and heavy metals concentration have been reviewed. Several cases of food crop production and the
accumulation of heavy metals after SS application are also discussed. SS production, usage, and legis lation in EU are assessed to determine the possibility of sustainable management of this bioresource.
Additionally, the World Health Organization (WHO) and Food and Agriculture Organization (FAO)
guidelines are addressed. The opportunity to produce bioenergy crops, employing sewage sludge to
enhance degraded land, is also considered, due to energy security. Although there are numerous
advantages of sewage sludge, proper screening for heavy metals in all the variants (biosolids, soil,
food products) is a must. SS application requires appropriate strict guidelines with appropriate
regulatory oversight to control contamination of agricultural soils.
Description
Keywords
By-products Biosolids Organic compounds Circular economy Total lifecycle assessment Biomass effect . Faculdade de Ciências da Vida
Citation
Nunes, N., Ragonezi, C., Gouveia, C. S., & Carvalho, M. Â. P. (2021). Review of sewage sludge as a soil amendment in relation to current international guidelines: a heavy metal perspective. Sustainability, 13(4), 2317. https://doi.org/10.3390/su13042317
Publisher
MDPI