Analysis of water quality in effluents from car washes and lubrication facilities in Santo Domingo

Abstract

Urban growth and the expansion of the automotive sector have increased the generation of wastewater from vehicle washing and lubrication activities, which contains potentially polluting compounds. The objective of this study was to evaluate the physicochemical quality of the effluents generated by these establishments in the Abraham Calazacón parish, Santo Domingo canton, and to verify their compliance with environmental regulations. The research, which was quantitative and descriptive in nature, was based on direct observation, surveys, and wastewater sampling. BOD₅, COD, oils and greases, temperature, and total suspended solids were analyzed, and the results were compared with the limits set by Ecuadorian regulations. It was found that 100% of the establishments use only primary treatment—primarily grease traps—which are insufficient to remove dissolved contaminants; furthermore, all establishments discharge their effluents into the sewer system. The BOD₅ (98 and 60 mg/L) and COD (235.84 and 195.95 mg/L) values complied with the established limits; the concentrations of oils and fats (<0.02 mg/L) and total suspended solids (<1 mg/L) were very low, demonstrating high efficiency in the removal of physical and oily contaminants; the temperature remained within the permissible range. Despite regulatory compliance, the presence of partially biodegradable organic matter and the absence of secondary treatment could lead to cumulative environmental impacts; therefore, best practices are recommended for the management of used oils, maintenance of grease traps, separation of hazardous waste, staff training, and efficient use of supplies.