Currently the most common practice for produced water management is disposal through injection into Class IID wells with minimal treatment. This option is costly and risky, especially for wells that are located far from the nearest disposal well. Under these circumstances, treating the produced water for reuse becomes an appealing option. This study investigates disposal and treatment options in detail to determine the economic feasibility of each treatment option compared to the available disposal option.
We used water production and well data from Marcellus Shale Energy and Environment Laboratory (MSEEL) to build a case study for the assessment of disposal, and membrane desalination options. We collected other necessary information such as disposal well location and desalination parameters from the Environmental Protection Agency and previously published papers. We investigated the following high salinity water treatment methods: high pressure reverse osmosis (HPRO), electrodialysis (ED), and direct contact membrane desalination (DCMD).
Under the assumptions of our study, we found that disposal costs less than HPRO and DCMD. ED, on the other hand, is less expensive than disposal and provides more flexibility in terms of the quality of the produced permeate. Our results also show that if the disposal well is farther than 100 miles from the MSEEL well pad, DCMD becomes more cost-efficient than disposal. As the salinity of the MSEEL produced water drops, the cost of HPRO and ED also decreases.
Produced water treatment reduces truck traffic and lowers the spill risk, emissions, and road wear. However, treatment options must be economically evaluated for each well to determine their feasibility. Our findings may serve as a guideline for economic evaluation of produced water management solutions.