NAWI has kicked off efforts to make non-traditional water sources cost-competitive with a focus on brine management, an area ripe with opportunity for produced water treatment technology developers.
On August 28, the National Alliance for Water Innovation (NAWI) issued a request for proposals (RFP) for innovations in intensified brine management, which is one of the challenge areas identified in its research program. The alliance will provide a total of $8 million for 4-12 early-stage applied research projects aimed at improving the costs and energy efficiencies of small-scale desalination systems.
The RFP is open to all interested parties that are developing ways to treat water streams with total dissolved solids concentrations of 75,000-250,000 ppm at half the cost of existing methods. According to the notice of intent, “several opportunities exist to move beyond state-of-the-art brine management approaches including novel systems, processes, and materials for minimizing brine production, concentrating brines to higher salinities and valorizing brine constituents.”
OPPORTUNITIES FOR INTENSIFIED BRINE MANAGEMENT
|“Evaporative processes e.g. mechanical vapor compression (MVC), humidification/dehumidification”||Phase transition, steep economy of scale, expensive materials||Modularity, low-cost thermal materials, small-scale systems, harnessing renewables|
|“Membrane processes using novel combinations of driving forces e.g. reactive membrane distillation, osmotically assisted reverse osmosis (RO)”||Novel driving forces and new combinations of traditional driving forces||Process optimization in multi-stage design, cost reductions, tailored membrane properties|
|“Operational innovations e.g. batch and semi-batch RO, flow reversal RO, high-pressure RO”||Manipulate the induction time for scaling , extend the operational range of the system||Integrated pretreatment, operando monitoring, predictive capabilities|
|“Electrically-driven processes e.g. electrodialysis (ED)”||Silica and chlorine tolerant, divalent separation for high-recovery RO||Low-cost ion exchange membranes, high permselectivity with low membrane resistance and water transference|
|“Cycling and extraction processes e.g. solvent extraction”||Possible advantages where low-temperature heat widely available, solvents non-hazardous||>99.99% solvent recovery, long solvent lifespan, low temperature swings, high water miscibility|
|“Innovative pretreatment e.g. selective removal prior to or during treatment”||Softening technologies often chemically intensive, avoid (or encourage) precipitation of hazardous contaminants||In-situ chemical generation|
The RFP is the first of several that NAWI plans to issue to achieve its goal of delivering technologies that enable 90% of non-traditional waters to be cost-competitive with the next available traditional water source for a specific end user. Chosen in September 2019 by the Department of Energy to lead the $100-million Energy-Water Desalination Hub, the alliance is focused on five end user types and nine non-traditional water sources, including conventional and unconventional produced water.
NAWI research director Meagan Mauter told WiO that transportation contributes to a large chunk of total water costs for non-traditional water sources due to high operating expenditures for water hauling and high capital requirements of permanent pipeline networks. Another major cost factor is treatment, which for higher-salinity sources like produced water, is energy-intensive and thus very expensive.
“The only way you’re going to be able to reduce costs significantly is to basically eliminate the contribution from transport,” NAWI research director Meagan Mauter said.
She explained that depending on the sector, costs could be reduced by 50-80% by cutting transportation out of the equation because transportation-related costs rise exponentially as water volumes grow. However, eliminating transportation would necessitate smaller treatment systems located closer to both points of origin and reuse.
FINDING THE SWEET SPOT
If technology providers are able to significantly lower water treatment costs in small-scale systems, then historically unusable water supplies could becomes valuable resources.
Small-scale water treatment is not able to realize economies of scale, making it more difficult to achieve cost-competitiveness. To address this, NAWI has identified six challenge areas that require innovation to make small-scale systems more economical:
- Autonomous treatment system operation
- Precision separation of low-concentration problem constituents
- Resilience of water treatment units
- Intensification of brine management processes
- Modularity of systems and expansion of membrane-based technologies for lower and higher salinity ranges
- Electrification of treatment trains
“You really need all six of these to come together if you’re going to enable small-scale distributive systems, especially at costs that are competitive with alternative water sources,” Mauter said.
To view the RFP, click here.