Contribution of organic bulking materials on chemical quality of sewage sludge vermicompost

Abstract

Vermicomposting is at suitable methods for stabilization and converting of sewage sludge into useful products. To investigate the effects of bulking material on vermicompost quality, an experiment was conducted in a factorial design with three replications. In this experiment, the final dried sludge in lagoons was mixed with bulking materials (woodchips, three leaves, and wheat straw) in four mixing proportion with swage sludge (0, 15, 30 and 45%, V/V). Chemical properties of bulking materials, sewage sludge, and produced vermicomposts were determined. Vermicomposts had relatively low pH and electrical conductivity (EC). The nutrients content of vermicompost, especially N, P, Fe, and Zn, were high. These properties showed its suitable quality for use in agriculture. Heavy metals concentrations of vermicomposts, except Zn, were lower than recommended values by EPA. Mixing of Bulking materials with sewage sludge decreased pH, N, Pb, Co, and Cd, but increased Ca, Mg, Fe, Cu, Mn, Zn, and Ni content of produced vermicomposts. In most cases, the concentrations of nutrients were higher in 30% mixing proportion. Therefore, 30% (v/v) mixing of bulking material with sewage sludge is recommended for vermicompost production.Index terms: Vermicompost, sewage sludge, bulking materials, heavy metals, Eisenia foetid. RESUMOA vermicompostagem é um métodos adequados para a estabilização e conversão de lodo de esgoto em produtos úteis. Para investigar o efeito de aumentar o volume de material sobre a qualidade do vermicomposto, foi conduzido um experimento em esquema fatorial com três repetições. Neste experimento, o lodo final seco em lagoas foi misturado com materiais de volume (lascas de madeira, três folhas e palha de trigo) em quatro proporções de mistura (0, 15, 30 e 45% V / V) com lodo de esgoto. Propriedades químicas dos materiais de amontoamento, lodo de esgoto e vermicompostos produzidos foram determinados. Vermicomposto apresentaram pH relativamente baixo e CE. O seu teor de nutrientes, especialmente N, P, Fe e Zn foram elevados. Essas propriedades mostrou sua qualidade adequada para utilização na agricultura. Concentrações de metais pesados de vermicompostos, com exceção do zinco, foram menores do que os valores recomendados pela EPA. A mistura de materiais Bulking com lodo de esgoto diminuiu o pH, N, Pb, Co e Cd, mas aumentou a concentração de Ca, Mg, Fe, Mn, Cu, Zn, Ni no vermicomposto produzido. Na maioria dos casos, as concentrações de nutrientes foram maiores na proporção de 30% de mistura Portanto, recomenda-se a mistura de materiais ao lodo na proporção de 30% para a produção de vermicomposto.Termos para indexação: Vermicomposto, lodo de esgoto, materiais de volume, metais pesados, Eisenia foetid.

Can sewage sludge increase soil fertility and replace inorganic fertilizers for pineapple production?

“…Furthermore, the formation of organomineral complexes between metals and humic compounds of the SS favors the displacement of Fe and Zn in the soil profile (Hashemimajd & Somarin, 2011). It is worth noting that the concentration of Zn does not constitute a restrictive factor for the agricultural use of sludge since the Zn concentration obtained was below the limit of 2,800 mg kg -1 (Brazil 2006).The increase in the content of soil Zn, after the use of sewage sludge, has been often reported in the literature (Latare et al, 2014;Nascimento et al, 2015;Li et al, 2020).…”

Gradual Accumulation of Heavy Metals in an Industrial Wheat Crop from Uranium Mine Soil and the Potential Use of the Herbage

“…One can accept the use of the Cd-contaminated wheat straw in rates of 15%-45% as bulking material in the vermicomposting of sewage sludge (e.g., [107]). Renouncing its use as a soil structure-improving material, however, does not really contribute to soil remediation.…”

Humic Substances and Chemical Properties of an Acrisol Amended with Vermicomposted Vegetal and Animal Residues

“…In this sense, vermicomposting is a low energy-demanding process that stabilizes the pH and lowers the C/N ratio of organic residues in a shorter time than the regular composting method (Castilhos et al, 2008;Cotta et al, 2015). The final product is more stable and nutrient-enriched than the original material, which are crucial properties for maximization of the fertilizing effect of vermicomposts and for optimization of machinery operations when these products are applied in the field (Hashemimajd and Jamaati-Somarin, 2011;Baldotto et al, 2012). Moreover, vermicomposts are rich in humic substances (HS) resulting from the humification of the plant and animal products.…”