(615c) Principals of Managed Irrigation with Coal Bed Natural Gas Produced Water

Coal Bed Natural Gas (CBNG) produced water may be characterized as having elevated sodium bicarbonate concentrations with or without an accompanying high salinity level. If untreated or inappropriately managed, the high volumes of CBNG produced water pumped from gas production wells can cause severe impacts to receiving streams under direct discharge scenarios or to soil productivity if applied to land surfaces in an uncontrolled manner. Given that much of the CBNG drilling being developed is in rural agricultural regions, the water itself would have a high value as a potential irrigation source if the salinity and sodium issues could be economically addressed. In areas with favorable soil conditions (i.e., low to moderate clay content), CBNG produced water with even relatively high sodium adsorption ratios (SAR) and low to moderate salinity concentrations can be successfully managed as an irrigation source using appropriate application technology and soil amendments (e.g., sulfur and gypsum) applied to the field's surface thus avoiding the need for more expensive in-line water treatment processes. This paper reviews the principal challenges and solutions to utilizing CBNG produced water as source water for irrigated agricultural.