By Jim C. Lozier, P.E., CH2M HILL Technology Fellow and Global Technology Leader for Membranes
Mr. Lozier will present the paper, Utilizing Membrane and Other Treatment Technologies to Achieve Sustainable Water Management Schemes for Industrial Facilities Located in Arid, Water Scarce Regions,” co-authored by CH2M HILL’s Michael Hwang and Ralph Williams, on Wednesday, October 3, at 4:30 pm in room 350 during WEFTEC. Learn more about CH2M HILL’s WEFTEC 2012 participation and technical sessions.
As water-intensive industries such as specialty manufacturing, power generation and mining continue to locate in relatively arid and water-constrained geographies, they are faced with water supply and wastewater disposal issues that are becoming increasingly complex and expensive. Due to the both geographic and hydrogeologic conditions, arid-region water supplies have elevated levels of total dissolved solids (TDS) and inorganics, requiring the use of demineralization technologies, most typically reverse osmosis (RO), as a key step to the production of high quality process water.
The disposal of the high salt waste produced from the RO, called reject (or concentrate), is a challenge because of the lack of naturally-occurring surface waters in which to discharge; or limitations on disposal to sewer because treated effluent is used for landscape irrigation or other non-potable uses. These constraints—lack and quality of water supply, and difficulties with high-salt discharges—are forcing industry to develop a more comprehensive approach to water management that incorporates water reuse and recycling. These strategies include innovative approaches to high-salt RO reject management, and in an effort to reduce overall water demands, reuse treated wastewater and limit the volume of RO concentrate requiring disposal.
During WEFTEC I will discuss a water management study conducted by CH2M HILL in the arid southwestern U.S. to evaluate treatment options for a high salinity RO reject that is produced as a waste stream from high purity water production. Increasing RO reject flows, coupled with a fixed volume within existing solar evaporation ponds for concentrate disposal, required the development of new approaches to reducing overall reject flows. Furthermore, water supply limitations required the treatment and reuse of the clean water recovered from the reject.
Technologies considered in the development of reject treatment and reuse schemes for this study included precipitative softening using lime, caustic soda and soda ash followed by conventional and novel solids clarification processes; tubular and hollow fiber micro- and ultra-filtration, nanofiltration (NF), electrodialysis reversal (EDR) and various configurations of RO (brackish and seawater spiral wound, high efficiency RO [HERO™], and disc-tube); thermally and electrically-driven evaporation; and passive and enhanced solar evaporation ponds.
The findings from this case study, which I will go into detail about at WEFTEC, illustrate that disposal of brackish waste streams, exemplified here by a RO reject produced from purification of a higher salinity municipal water supply, is both challenging and expensive. While the use of membrane-based desalination may appear to be less expensive based on its considerably lower energy use, the need for chemically intensive pretreatment can result in a higher total water cost than thermal based desalination methods, depending on what degree of volume reduction is necessary. As importantly, the use of evaporation ponds for final (zero) liquid discharge must carefully consider a number of factors to ensure that adequate pond capacity is provided, particularly when disposing of hypersaline brines, where evaporation rates are low salt accumulation is significant.
The results underpin the need for an effective industrial water management approach that moves away from the ‘use it once and discharge’ approach to one that balances high purity water production with sustainable management of saline waste steams with the objective of maximizing recovery and reuse and minimizing impact to the environment. I look forward to discussing further with you at WEFTEC, or if you aren’t attending, please don’t hesitate to contact me for more information.
Jim Lozier is a Technology Fellow within the CH2M HILL Water Business Group and specializes in the application of membrane processes for water treatment, desalination, and water reuse. He has 28 years of experience in evaluating, designing, and implementing a wide variety of membrane technologies, including reverse osmosis, nanofiltration, ultrafiltration, microfiltration, and electrodialysis. Lozier received a masters of science at the University of Arizona. He is also a member of the American Desalting Association, American Society of Civil Engineers, Arizona Water Environment Association, and the American Water Works Association. Lozier is trained in hazardous communication and is involved in the global technology department in the Phoenix department.
Tags: brackish waste streams, CH2M HILL Access Water, industrial wastewater, Jim Lozier, reverse osmosis, wastewater, wastewater management, water blog, water management, WEFTEC, WEFTEC 2012
