Combined DAF and Biological System Treats Vehicle Washing Wastewater

A vehicle washing service center expanded its operating bays and needed to improve the treatment of wastewater generated during daily cleaning. The existing settling arrangement could not manage changing flows or the combination of grit, suspended solids, oil, and detergent residues.

The project team planned a treatment line that begins with screening, grit removal, and flow equalization. These steps protect the downstream equipment and provide a more consistent feed for chemical and biological treatment.

Zhongqiao Enlightenment recommended dissolved air flotation as the main pretreatment stage, followed by an integrated biological treatment unit. The DAF process removes floatable contaminants and fine suspended solids before the wastewater enters the anoxic and aerobic stages.

Chemical dosing, mixing, flotation, sludge discharge, aeration, and disinfection interfaces were coordinated as one process package. This arrangement reduced the need for separate on-site fabrication and helped the operator understand the complete treatment sequence.

The DAF unit was configured with an access platform, operating stairs, flotation tank, and associated dosing equipment. The packaged biological unit provided protected space for the subsequent process and routine inspection points.

Before shipment, Zhongqiao Enlightenment checked the tank coating, structural supports, pipelines, access openings, electrical interfaces, lifting points, and transport protection. Connection labels and delivery documents were prepared for the installation team.

At the site, the pretreatment and biological units were connected to the screened collection tank, equalization system, sludge-handling line, power supply, air supply, and treated-water outlet. Commissioning focused on adjusting dosing and aeration for changes in washing activity.

The combined system gives the vehicle washing center a more organized approach to solids, oil, and biodegradable contaminant removal. Separating pretreatment from biological treatment supports cleaner operation, easier maintenance, and more stable wastewater management.