Membrane distillation is a process where water contaminated with dissolved solids is evaporated across a membrane barrier creating clean water without the dissolved solids. The process uses heat to drive the evaporation and is a major part of the cost of this process. Waste heat can be low-cost driver.
RO Reject Water Recovery and Reuse Using Waste Heat and Membrane Distillation
Learning Station II: Sustainability
Electrocoaters use Reverse Osmosis (RO) to create clean water to wash parts. This generates a wastewater stream that has a high concentration of dissolved solids. Membrane Distillation can be an efficient way to evaporate that water creating low dissolved solids clean water that can be reused reducing wastewater treatment and city water usage. The membrane distillation process typically is not very cost-effective due to the amount of energy needed to evaporate the water. The use of waste heat from the curing ovens can overcome that cost disadvantage. This paper will highlight the results of a pilot study done treating RO Reject Water providing insight on the quality of the distillate water and the recovery efficiency using a Duel Tangential Flow Spiral element with a ePTFE membrane.