Harmony team demonstrates batch RO in the field, wins challenge, continuing development
Harmony Desalting team wins the More Water Less Concentrate Challenge, starts long-term testing supported by Yuma Desalting Plant, Bureau of Reclamation, MassCEC Catalyst Program
Last July, a team composed of Olin College of Engineering, Harmony Desalting, and MIT was named one of five finalist teams in the Bureau of Reclamation’s More Water Less Concentrate Challenge. The MWLC challenge spurred the development of innovative approaches to reducing concentrate volumes while increasing recoveries. Concentrate disposal is particularly expensive at inland desalination plants like the Yuma Desalting Plant in Arizona. Each finalist team was awarded $115,000 to design and build a prototype to be tested at the YDP in June and July of this year. The teams demonstrated a variety of technologies: electrodialysis, thermal distillation, and reverse osmosis (RO).
One limitation to increasing water recovery with RO membranes is scaling: crystallization of sparingly soluble salts on the membrane surface impairs performance and necessitates water conditioning or membrane cleaning with harsh and costly chemicals. Our patented technology, batch RO, reduces the likelihood of scaling and the need for chemical usage. Batch RO operates in short (~10 minute) cycles with three phases: flush, recharge, and permeate production. The membranes are only exposed to supersaturated conditions briefly at the end of each permeate production phase and then immediately rinsed with freshwater when the system is de-pressurized as the cycle begins again.
The batch RO prototype was constructed and tested at Olin (Needham, MA) from December 2021 through May 2022. The demonstration took place July 26-August 2 at the Water Quality Improvement Center of the Yuma Desalting Plant with two weeks of set-up time beforehand. This was the first time batch RO with a flexible bladder has operated in the field. Over the seven day demonstration, our 1 gpm (5 m3/day) system reduced YDP’s RO brine (8990 us/cm) volume by 83% and operated with 92% uptime while consuming 616 Watts and producing clean water (150 mg/L). We saw no apparent signs of membrane scaling or fouling throughout the demonstration.
On September 9th, the Bureau of Reclamation announced that the Olin-Harmony-MIT team won the More Water Less Concentrate Challenge, taking home $150,000 in prize money. The money will support Prof. Emily Tow’s research into RO membrane scaling and Harmony’s commercialization of batch RO. The Massachusetts Clean Energy Center (MassCEC) Catalyst Program has also awarded Harmony Desalting $65,000 to test and develop batch RO for the reliable treatment of harsh waters. Batch RO is well-suited for the treatment of corrosive liquids such as mining waste because the bladder protects the high pressure pump. Harmony will use Catalyst funds to scale-up the batch RO technology and begin work on a commercial pilot.
On August 18th, Harmony Desalting commenced a 113 day test of the batch RO prototype at the Yuma Desalting Plant. The YDP was designed and constructed to conserve Colorado River water while fulfilling treaty obligations to Mexico regarding discharge salinity levels by desalinating agricultural drainage water from the Main Outlet Drain Extension (MODE). The YDP is a unique location for this long-term testing due its water source and 24/7 monitoring. Over the next three months we will demonstrate the reliability of the batch RO process and learn more about its ability to resist membrane scaling. We are grateful for the support of the operators at the Yuma Desalting Plant, the Bureau of Reclamation, and the Massachusetts Clean Energy Center to make this testing possible.
Yuma Desalting Plant long-term test data (updated weekly on Wednesdays)