Growing Trend Toward Reuse and "Zero Liquid Discharge
As water costs increase and supplies dwindle, more and more industries are turning to high-tech water treatment systems that recycle and reuse water within plant production processes. Some of these systems include "closed loop" technology--known as Zero Liquid Discharge (ZLD)--that recycles all in-plant water streams and discharges none to the environment.
The trend is benefiting companies like USFilter, Palm Desert-based supplier of total water management systems and services, which reports a wave of new bookings for ZLD and other industrial water reuse systems.
"We've booked more than $80 million in ZLD and industrial water reuse systems during the current fiscal year," says Frank Firsching, president of USFilter's systems group. "We have many more in the pilot testing and proposal stages."
One of the new projects is for Constellation Energy Group's new High Desert Power Project in Victorville, Calif. The 750-megawatt plant will be the first new major power plant to be built in Southern California in more than a decade.
USFilter will provide a wide range of integrated technologies to meet the entire scope of water treatment needs for the power plant, including pre-treatment of raw water, treatment of cooling tower blow-down, and treatment and recycle of all wastewater. Commercial operation is scheduled for July 2003.
"Power plants and other industrial operations can require large quantities of water," Firsching explained. "It takes 8 to 9 gallons of water to produce just one kilowatt hour of electricity. It can take 50,000 to 100,000 gallons of water to manufacture an automobile."
Firsching said USFilter's ZLD systems use high-end technologies such as membrane filtration to treat raw water to high-purity standards, to facilitate use in industrial processes. Next, the wastewater from these industrial processes is treated with similar technology, restoring it to a contamination free status to enable re-use.
As a result, industrial plants installing ZLD systems can expect to recover close to 100 percent of water that would otherwise be discharged to environment as wastewater.
"That's very good news in areas where accessible clean water is becoming a scarce resource," Firsching said.
In addition to power generators, USFilter is providing water reuse systems for a variety of other industrial clients.
In the automotive sector, USFilter has supplied ZLD systems to several customers in Mexico, where resource conservation is critical. One of the projects, a Daimler-Chrysler truck production facility in Saltillo, Mexico, was the first to employ ZLD when it started to treat and recycle water in 1996. Industrial wastewater is purified and returned to the manufacturing plant. Sanitary wastewater is treated and reused for irrigation.
In the oil and gas market, USFilter has supplied a water reuse system to a California refinery. Wastewater from the production of petroleum-based products and a co-generation facility are treated with a variety of technologies, including carbon adsorption and reverse osmosis, then reused in boilers and cooling towers.
A Sasol Polymers plant in South Africa uses USFilter systems to purify wastewater from the production of vinyl chloride monomer. The high-quality recovered water is piped to other production processes at the site.
USFilter also is participating in several projects where industries take treated wastewater from a municipal treatment plant, treat it further, and then use it for industrial purposes - reducing stress on scarce drinking water supplies.
Firsching believes that while the cost and availability of water are strong market drivers, the availability of cost-effective, proven technology is having a positive effect, as well.
He said advancements in membrane filtration, liquid-solid separation, and deionization, and the integration of these technologies into complete systems has given industrial clients proven technical solutions for water reuse.
"As ZLD and water reuse systems become more common, and the true costs of clean water are recognized, the technology becomes increasingly more feasible and cost effective. We expect to see more projects of this type."
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