Characterization and Criteria for the Management of Sludge Generated During the Treatment of Groundwater: Case Study in the City of Morelia, Michoacán, Mexico

Objectives: To characterize sludge generated at a groundwater drinking water treatment plant in Morelia, Michoacán, Mexico, and establish preliminary management criteria. Theoretical Framework: The study addresses drinking water treatment sludge characterization and management, as well as Mexican Standard NOM-004-SEMARNAT-2002. Method: A quantitative, descriptive case study was conducted. A composite sample was collected from the thickener at the La Mintzita plant. Moisture, total and volatile solids, heavy metals, fecal coliforms, Salmonella spp., and helminth eggs were analyzed. Results and Discussion: The sludge contained 98.10% moisture and 1.90% total solids. Volatile solids accounted for 21.50% of total solids, equivalent to 0.4085% of the wet sample. Arsenic was 1.528 mg/kg; the other metals were below their quantification limits. Fecal coliforms measured 28 MPN/g total solids, Salmonella spp. was below 3 MPN/g total solids, and no helminth eggs were detected in 2 g of total solids. Results were compatible with the reference values for Excellent-type and Class A biosolids for the parameters assessed. The high moisture content indicates that dewatering is necessary before beneficial use is considered. Research Implications: The findings support the evaluation of thickening, dewatering, and beneficial-use alternatives. Originality/Value: The study provides specific data on sludge from a groundwater treatment plant and proposes a management pathway involving dewatering, further characterization, and evaluation for beneficial use or final disposal.