Overview:

Fleet washing operations generate large quantities of wastewater containing free and emulsified oils, detergents, heavy metals, suspended solids, and other contaminants. Management of washing wastewater varies from activity to activity. However, the most prevalent practice used involves treatment with an oil/water separator (OWS) prior to discharging into a sanitary sewer. This practice is not recommended due to the emulsifier oils generated by the detergents and heavy metals found in waste stream. Conventional OWSs do not remove these contaminants, which are commonly found at levels that exceed sanitary sewer discharge limits.

A closed-loop washing wastewater recycling system helps facilities achieve compliance with discharge limits while reducing water and detergent usage. As environmental regulations continue to set more stringent discharge limits for wastewater contaminants, recycling becomes even more justified since regulatory agencies grant permitting exceptions to activities that recycle wastewater.

Numerous systems are commercially available including one developed by Superior Wash. In general, systems are purported as capable of removing containments from wastewater to the following concentrations: oils to less than 10 ppm, heavy metals to less than 0.1ppm and suspended solids to 1 ppm.

Superior Wash recovery/recycling systems are described in the following paragraphs. Fleet equipment was and rinse water is collected from a wash pad or other comparable paved surfaces and pumped via a high powered vacuum system to the systems load equalization tank (LET) until sufficient water is collected. Prior to washing all drains are sealed and booms placed around the drain to direct the flow to the high power vacuum system. Once the job is concluded, Superior Wash then takes the recovered wastewater to out facility for recycling. The wastewater from the LET is then pumped to the recycling system. Inside the recycling system a corrugated parallel plate separator removes free oil. Next the system adds demulsified to treat emulsified oils, sodium hydroxide to precipitate heavy metals, and hydrogen peroxide as disinfectant.

Following the chemical additions, the solid generated by the chemistries are removed through an automated pre-coat indexing filter. The treated water is then pumped into a holding tank where it is to be utilized by being pumped back into the truck soap cycle water tanks and used for soap cycles only.

Closed-loop wastewater recycling systems require scheduled maintenance to insure satisfactory performance. This may include replacing or cleaning of filters.

Compliance Benefit:

Use of a Superior Wash closed-loop wash recycling system complies with Executive Orders 13123 and 13148 requiring federal facilities to implement water conservation projects and to reduce offsite hazardous waste disposal. The system may also help facilities to meet the waste reduction requirements of RCRA (40 CFR 262). Superior Wash closed-loop system meets the EPA standards.

The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, ex…, the amount of workload involved.

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