Irrigation accounts for 42% of the total freshwater withdrawals in the United States. Climate change, the pressure of a growing population, degrading water quality, and increased competition from other sectors could constrain continuous supply to meet future agricultural water demand. This study presents an evaluation framework to assess the potential reuse of agricultural drainage water for crop irrigation. Using a regional approach, we review the current state of agricultural drainage treatment and reuse and the institutional, economic, and other barriers that can influence the reuse decision. In the 31 eastern states, agricultural drainage contains valuable nutrients that can be reused for irrigation with minimal treatment, while the 17 western states struggle with large volumes of saline drainage that can contain constituents of concern (e.g., selenium), preventing reuse without treatment. Using a new decision-support tool called WaterTAP3, a potential treatment train for saline agricultural drainage was analyzed to identify treatment challenges, research needs, and the potential implementation at a larger scale. As demonstrated by our case study, desalination of agricultural drainage is costly and energy intensive and will require sizable investments to fully develop and optimize technologies as well as manage the generated waste and brine.

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The effective treatment of unconventional oil and gas (UOG) wastewater is a promising and potentially necessary strategy of wastewater management in the UOG industry. While tremendous efforts have been focused on the development of treatment technologies, logistical considerations such as wastewater transportation have been rarely studied in the literature. In this study, we applied spatial analysis tools based on geographic information systems to quantitatively investigate the effects of transportation distance and cost on centralized wastewater treatment (CWT) and deep-well injection (DWI) in Weld County of Colorado, a major UOG-producing state in the United States. CWT using membrane distillation technology powered by waste heat from natural gas compressor stations (NGCSs) was used as the model wastewater treatment approach in our analysis. By analyzing 7583 active UOG production wells, we demonstrate that the distance and cost of wastewater transportation for CWT are comparable to those for DWI in Weld County and that the comparison between CWT and DWI is dependent on the scale of analysis. We also correlated the waste heat availability with the potential UOG wastewater treatment demand at 35 NGCSs. Our analysis shows that the abundance of available waste heat does not always match wastewater treatment demand at NGCSs, requiring a diversion of wastewater that further increases the transportation distance and cost. Our work indicates the importance of logistical considerations in evaluating the viability of CWT for UOG wastewater management. The spatial analysis framework demonstrated in this study is a critical component complementary to the current efforts of treatment technology development, in order to better evaluate the viability and facilitate wide adoption of UOG wastewater treatment via a systems engineering approach.

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