Depth Filtration with a Moderate Application Rate for the Treatment of Carwash Wastewater

The development of low-cost and practicable technologies for the treatment of wastewater will be essential to ensure the adequate disposal of the residues generated by carwash businesses. The present study developed a novel wastewater treatment system, based on the Depth Filtration with a Moderate Application Rate (DFMR), which is a low-cost alternative for the treatment of carwash wastewater with simple operational and servicing technology. The proposed system was composed of sequential depth filtration units, containing gravel, zeolite, and activated charcoal as the filtration media. A parallel system, composed of additional gravel and zeolite filters, was also installed, to provide an operational safety valve. At an application rate of 45.7 m3.m–2.day–1, the system obtained 90.8% efficiency for the reduction of turbidity, and 72.4% for the removal of COD and 54.9% for surfactants, achieved exclusively by the application of a depth filtration process. These results highlight the potential of the proposed system as a low-cost and practicable alternative for the adequate treatment of wastewater produced by small- and medium-sized carwash businesses.