Using Ultrafiltration to Achieve Stringent Heavy Metal Discharge Limits and Effluent Reuse for Engine Remanufacturing Wastewater

A Class 1 Railroad initiated a pilot study to evaluate the effectiveness of the ultrafiltration technology in treating process wastewater generated from their locomotive engine remanufacturing facility located in Pennsylvania. The local Water Authority enforces stringent metals limits. The chelated heavy metal laden wastewater required a treatment system much more effective than the current conventional physical-chemical pretreatment system. Two different types of ultrafiltration systems were evaluated: 1) Modified batch system; 2) Proprietary buoyancy-enhanced system. The results indicated that the ultrafiltration system was an effective and sustainable treatment technology to meet the stringent standards. However, the colder temperatures, as can be seen in Pennsylvania, caused significant flux drops in the modified batch system. Wastewater required heating with high energy costs or oversizing of the units. The buoyancy-enhanced ultrafiltration system, with the introduction of compressed air could maintain flux rates at lowered temperatures and was thus chosen for the final design.