Analysis of the Performance of a Wastewater Treatment Plant at a Cosmetics Industry: A Case Study in Minas Gerais, Brazil

The cosmetics industry generates highly complex and polluting wastewater that requires treatment to mitigate environmental impacts. This study analyzed the performance of a wastewater treatment plant (WWTP) at a cosmetics industry in the state of Minas Gerais, Brazil, which employs screening, an anaerobic baffled reactor, and an activated sludge system. WWTP monitoring data collected over four years were evaluated regarding pollutant removal to ensure compliance with discharge standards in the receiving water bodies. Average COD and BOD5 removal efficiencies were notably high, at 96.0% and 98.1%, respectively. The other mandatory parameters monitored (pH, surfactants, oils and fats, settleable solids, total suspended solids) were also in compliance with discharge standards. Linear correlation analysis between BOD5 and COD indicated a weak relationship for raw wastewater (R2 < 0.5) and a moderate relationship for treated wastewater (R2 between 0.5 and 0.8). Sensitivity analysis indicated moderate correlations for both raw and treated wastewater; however, the relationships were insufficient for reliable estimation of BOD5 from COD. When considering reuse, even with the good performance of the WWTP, the treated wastewater did not meet the typical criteria for direct use as feedwater in the cosmetics industry’s wood-fired boilers based on the evaluated COD and pH values. Unlike wastewater and atmospheric emissions, various sustainable solid waste management strategies—such as composting sludge to produce fertilizer and recycling—are adopted by this industry. The results of this study highlight the contribution of wastewater treatment and resource management to the sustainability of the cosmetics industry.