Vermicomposting as a sustainable alternative for the stabilization and utilization of industrial brewery wastewater sludge

Abstract

Industrial brewery wastewater sludge (BWS) is generated in large volumes, causing environmental contamination issues due to its high organic matter content and, in some cases, the presence of heavy metals, toxic substances, pathogens, and emerging contaminants. Vermicomposting is a promising alternative for stabilizing organic waste. Once the process is completed, the end product (vermicompost) can be applied to soils, improving their structural, physicochemical, and fertility properties. The objective of this study was to investigate vermicomposting as a strategy for stabilizing wastewater sludge from the brewing industry and to determine the final quality of the product. To achieve the objectives, eight vermicomposting units were established with different proportions (25%, 50%, 75%, and 100% w/w) of sludge and stabilized material. Over 10 weeks, various parameters such as moisture, pH, and organic matter were monitored and analyzed. Subsequently, the products underwent a 4‐week maturation process. To determine if the mature products comply with the minimum requirements of the corresponding regulations, parameters such as C/N ratio, organic matter, cation exchange capacity (CEC), faecal coliforms, heavy metals, pH, germination index (GI), and moisture were analyzed. The 25%, 50%, and 75% brewery sludge units met the established requirements and can therefore be used for agricultural, forestry, and commercial vermicompost applications. The 100% sludge ratio did not comply; however, the maturity stage time can be extended to meet the standards. In conclusion, the vermicomposting stabilization of brewery industry sludge is a viable alternative for obtaining value‐added products.