Wastewater Reuse Considerations at a Petroleum Refinery

Concerns regarding the sustainability of the water source used by a Midwestern petroleum refinery have driven the pursuit of alternative sources of water. The refinery presently relies on its groundwater wells and the local municipal water authority for its process water. Both of these water sources utilize the same aquifer, and ongoing monitoring indicates the aquifer is gradually being depleted by the municipality, irrigation of agricultural crops, and the refinery.In response, the refinery commissioned a front end engineering design study to evaluate process alternatives for reclamation of the refinery's wastewater for reuse within the refinery, and to further develop the selected alternative. In addition, the refinery embarked on a major upgrade of its existing wastewater treatment infrastructure, including new API separators and DAF clarifiers. Experience gained from treatment and reuse of refinery wastewater at several Pemex refineries in Mexico served as a foundation for development of a treatment scheme at the refinery, including cold lime softening for production of cooling water, and cold lime softening followed by low pressure membrane filtration and reverse osmosis for the production of boiler feed water.This paper reviews the wastewater reuse experience at several Pemex refineries in Mexico, and describes the application of that experience as it relates to wastewater reuse at the Midwestern refinery. Details of the design and operation of the wastewater infrastructure upgrades are also discussed.