Wastewater Reuse at a Petroleum Refinery

Concerns regarding the sustainability of the water supply currently utilized by the National Cooperative Refinery Association (NCRA) petroleum refinery in McPherson, Kansas have resulted in a desire to pursue 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 the Reclaimed Wastewater Treatment System (RWWTS) Front End Engineering Design (FEED) study to evaluate process alternatives for reclamation of the refinery's wastewater for reuse within the refinery, and to further develop the selected alternative.A project is currently underway to upgrade the refinery's existing wastewater treatment processes, including new API separators and DAF clarifiers. Other existing refinery wastewater treatment equipment includes sequencing batch reactors and cloth filters. Experience gained from treatment and reuse of refinery wastewater at several Pemex refineries in Mexico (Falcón and Romano, 2006) served as a foundation for development of a treatment scheme at the NCRA 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 NCRA McPherson refinery.