Wastewater Treatment at the Dearborn Engine Plant

In 2007, the ultrafiltration wastewater treatment plant at our Dearborn Engine Plant had reached the end of its useful life. At the time, the plant used ultrafiltration to process wastewater that contained heavy metals, suspended solids, free oils and stable oil-water emulsions. The plant also used a chemical batch process to treat wastewater that had a significant volume of surfactants, in addition to free and emulsified oils. A cross-functional planning team assessed these wastewater streams and treatment systems to see if they could find a more efficient process. The team found that they could significantly improve the environmental and economic performance of their wastewater treatment systems by in fact changing their whole approach.

Replacing the ultrafiltration plant was going to cost approximately $300,000, and the new system would require almost 40 person-hours a week to operate. However, the team found that they could eliminate the ultrafiltration system entirely, and reduce the wastewater sent to the chemical treatment system, if they separated their primary wastewater streams and treated them separately.

Previously, the process combined oily engine machining wastewater streams with soapy fuel tank wastewater, which resulted in large amounts of grease in the wastewater. The grease caused maintenance problems, required the use of large amounts of treatment chemicals and resulted in a high volume of low-quality wastewater residuals.

The team's analysis found that the soapy fuel tank wastewater did not need chemical treatment. Therefore, that wastewater stream could be treated separately using a simple physical device to remove floating and settling solids, thus reducing the need for the ultrafiltration system. Based on these findings, the team changed course. Instead of installing a new ultrafiltration system – the original impetus for the study – they installed a system to separate the soapy fuel tank wastewater and treat it separately.

This new process offers significant environmental and cost advantages. It reduced the volume of wastewater being treated with chemicals from 3 million gallons per month to less than 750,000 gallons per month – thus also reducing the labor required to operate the wastewater treatment plant. The new process also reduced the amount of chemicals required, increased the percentage of recyclable oil and reduced the amount of sludge, which requires landfill disposal. It also lowered wastewater storage volumes and increased storage capacity, thereby greatly reducing the possibility that an equipment malfunction could result in a wastewater spill to the environment or the city's wastewater treatment plant. The system saved the Dearborn Engine Plant $493,944 in the first year, after installation costs. It is expected to reduce annual wastewater treatment costs by $337,000.

The Dearborn Engine Plant received an Environmental Leadership Award from Ford's Environmental Quality Office (EQO) for developing and implementing this process. These awards are given by the EQO to recognize and promote ideas that are improving the environmental performance of Ford's manufacturing plants. Projects are judged on environmental leadership, environmental benefit and financial aspects.