Assessment of carwash wastewater reclamation potential based on household water treatment technologies

Abstract This paper assesses a bench-scale carwash wastewater treatment system's removal efficiency based on coagulation-flocculation and a household-type activated carbon filter and water ozonator. For the experiment, the wastewater that went through an oil/water separator (OWS) from a medium-sized carwash facility located in a dense commercial area in Barranquilla, Colombia, was collected. The study evaluates the following parameters: water quality indicators recommended by the U.S. Environmental Protection Agency and literature related to carwash water reclamation. The treatment results are compared to related regional studies in Latin America and Colombian legislation in force. Experimental results evidence that reclaimed water's characteristics are similar to those of a groundwater source for most analyzed variables, and the system was able to reduce organic matter concentrations considerably. Regarding the organoleptic characteristics, the system eliminated foaming and generated a transparent and odorless product. The coliform test showed that reclaimed water has an average total coliform count of around 5800 MPN/100 ml, which is above the proposed health risk limit per most international standards for water reuse; but as it complies with industrial wastewater and non-food irrigation purposes in Colombia, additional disinfection is recommended depending on the reuse purpose. The results from this research may assist future carwash wastewater reclamation regulations in Colombia and the Latin American region.