Abstract

The recycling and reuse of produced water (defined as hydraulic fracturing flowback water and formation water) is an increasing practice driven by competing demands for water sources and limited options for produced water disposal. The final disposition of reused/recycled produced water dictates the level of treatment with typically minimal treatment required when produce water is reused for fracturing subsequent wells and higher levels of treatment required when produced water is recycled for other purposes or potentially discharged to surface water bodies. The latter scenario, discharge of treated produced water is specifically addressed. Clean Water Act National Pollutant Discharge Elimination System (NPDES) permits for direct discharge of oil and gas generated discharge are currently prohibited east of the 98th meridian. West of the 98th meridian, direct discharge of treated oil and gas wastewater is allowed under specific conditions. Regardless of location (east or west of the 98th meridian), centralized wastewater treatment facilities (CWTs) can be permitted to treat and discharge oil and gas wastewater or CWT discharge may be accepted for further treatment and ultimate discharge at publically owned wastewater treatment facilities (POTWs). The EPA is currently developing effluent limitation guidelines (ELGs) for pretreatment of oil and gas wastewater sent to POTWs for treatment and discharge and recently submitted for comment Final 2012 and Preliminary 2014 Effluent Guidelines Program Plans; both addressed in this paper. Discussed are the various treatment technologies currently deployed and permitting issues associated with the treatment facilities. When treating produced water for discharge, constituent levels in the effluent stream and the waste side streams (consisting of a concentration of constituents removed as part of the water treatment processes) must be monitored to ensure proper management.

You can access this article if you purchase or spend a download.