Water & Wastes Digest recently discussed membrane-related technology and issues with membrane expert, Dr. YuJung Chang, vice president/national director of advanced water treatment for HDR Inc.
WWD: Do you think membrane filtration is a key to solving the world’s water-related problems?
Dr. YuJung Chang: Yes. With the demand of water supply increasing constantly and the available unpolluted water resource depleting, many metropolitans and fast-growing communities are tapping into less-desirable water sources. Regardless of raw water quality, membrane technology will be the most dependable treatment processes to ensure public health around the world.
WWD: How do membranes effect water quality?
Dr. Chang: Membranes are highly effective filtration devices with numerous tiny pores on the filter surfaces. With the assist of pressure or vacuum, raw water passes through those membrane pores, but impurities that are bigger than the pores cannot go through and therefore are separated from the treated water. Membranes with larger pores (e.g., microfiltration and ultrafiltration membranes) are able to remove pretty much all particulate materials, including small pathogens. Membranes with smaller pores (e.g., nanofiltration and reverse osmosis) can remove soluble contaminants and small ions, such as sodium and chloride.
With appropriate design, membranes can remove almost all of the undesirable contaminants from any water supply.
WWD: How would you describe the current membrane marketplace and what companies make up the major suppliers?
Dr. Chang: Before 1990, membranes were used primarily for industrial water supply, industrial wastewater remediation and seawater desalination in limited regions in the world. Since then, membrane technologies are now widely adopted by municipalities for water supply and wastewater treatment and the growth of membrane market place has been phenomenal. In 2003, the overall membrane market value in U.S. was about $2 billion. With an average annual growth rate of 8.3%, the sale of membranes in the U.S. market is expected to reach $3 billion by 2008. There are currently more than 500 membrane companies around the world. Major membrane suppliers for U.S. market include Dow (Filmtec), Hydranautics, Koch Membrane Systems, Ionics, Zenon Environmental, USFilter, Pall and Norit.
WWD: Do you envision an increase in the installed membrane capacity in North America in the upcoming years?
Dr. Chang: Absolutely. New regulations on the protection of public health from waterborne pathogens and more stringent limitations on the wastewater treatment plant discharge have already put membranes on the top choices for compliant technologies. The growing demands on the use of seawater desalination and wastewater recycling as part of regional alternative water resources will further warrant a strong growth for membranes in North America.
WWD: What are some of the implementation challenges faced by those who are interested in incorporating a membrane-based treatment system?
Dr. Chang: Membrane systems come with a wide variety of choices. Selecting the right membrane technology that would work under a set of specific site conditions is probably the number one implementation challenge. Using appropriate operation protocol and membrane cleaning methods would be the most critical challenge for day-to-day operation. From the regulatory compliance perspective, the assurance of maintaining adequate pathogen removal by the membrane system is the most prominent issue for surface water treatment. For brackish water treatment and seawater desalination, brine disposal is almost always on the critical path for permitting.
Finally, although the cost of membrane equipment has dropped to a point that’s very competitive with conventional treatment, the overall cost could be still on the higher end, particularly for systems that have capacities less than 20 MGD
WWD: Globally, how common will membrane-related technology become in the future?
Dr. Chang: Simply put, membrane-related technology will be the technology of choice in the future. To date, membrane is the only practical technology—other than distillation—that can offer a near-complete treatment to all types of water applications. The increased demand in high-quality water, the increasing pressure of utilizing alternative water sources, the aggravating water pollution, and the relentless R&D efforts that keep advancing membrane technology are the main drivers that will make membranes the obvious choice in the developed and developing countries in the next 10–20 years.
EPA: Substantial Decline
According to a new report from the EPA, sewer overflows cause up to 860 billion gallons of wastewater to be discharged annually into U.S. rivers and lakes.
The report recommends $140 billion over 20 years to solve the problem.
The report to Congress, “Impacts and Control of Combined Sewer Overflows & Sanitary Sewer Overflows,” does not make recommendations on how to solve overflows but details the numbers of overflows, costs of controls, and health and environmental impacts.
According to the report, 756 communities in 32 states have combined sewer systems with 9,348 outfalls regulated by 828 NPDES permits. EPA estimates that CSOs discharge 850 billion gallons of untreated wastewater annually.
The report cites EPA’s Clean Water Needs survey which discussed the need for a greater investment of $140 billion to curb CSOs by 85% and control SSOs. The primary funding mechanism is the Clean Water State Revolving Loan Fund. Although in the past it has been appropriated at $1.35 billion, the Bush Administration only requested $850 million in FY05, severely diminishing any hope that sufficient funds would be available to address overflows.
The report is available at: http://cfpub.epa.gov/
Water Quality Test Kits Available for World Water Monitoring Day
The U.S. EPA joined America’s Clean Water Foundation in issuing an invitation to citizens worldwide to monitor the water quality of their waterways, wetlands, coastal waters and inland waterbodies.
Specifically, the EPA and ACWF are encouraging people and organizations to participate in the second annual World Water Monitoring Day, Oct. 18. Volunteers and organizations are expected to measure their watersheds for four basic indicators—dissolved oxygen, pH, turbidity and temperature.
World Water Monitoring Day was created with two major purposes in mind. First, to serve as an educational platform to introduce people to the importance of water monitoring and connect them personally with efforts to protect and preserve their local watersheds. Second, as a means of expanding the base of information available about the health of each watershed over time
For info visit www.worldwatermonitoringday.org.
B&V Pros Recognized
Black & Veatch’s Pete Goins, Dave Parker, Chris deBarbadillo and Cindy Wallis-Lage recently received the prestigious George Bradley Gascoigne Medal from the Water Environment Federation during WEFTEC.04 in New Orleans.
The team was recognized for their article, “Build a Better Nutrient Trap,” which identified and discussed the process used to remove phosphorus from the effluent to enable the plant to operate efficiently and more easily accommodate additional future loadings. Specifically, the McDowell Creek (N.C.) Wastewater Treatment Plant, a 6 MGD activated-sludge facility, was upgraded to biological nutrient removal in 1999. Several operating strategies were tested and the recommended strategy was implemented and has yielded annual net savings of $150,000.
In addition, James H. Clark, a B&V vice president and senior project manager based in Los Angeles, received the prestigious Charles Alvin Emerson Medal from WEF. Clark was recognized for his many significant contributions during his term as a WEF officer.
New AMSA President, Officers
The Association of Metropolitan Sewerage Agencies’ board of directors recently elected William B. Schatz to serve as the association’s president at their 2004 National Environmental Policy Forum.
Schatz [second from right] is general counsel for the Northeast Ohio Regional Sewer District, Cleveland. Schatz succeeds Thomas R. “Buddy” Morgan, general manager of the Montgomery Water Works & Sanitary Sewer Board, in Montgomery, Ala.
In addition to AMSA’s new president, the association’s new officers include vice president, Donnie R. Wheeler [second from left], general manager, Hampton Roads Sanitation District, Virginia Beach, Va.; treasurer, Dick Champion, Jr. [far right], director of the independence Water Pollution Control Department, Independence, Mo.; and secretary, Christopher M. Westhoff [far left], assistant city attorney, public works general counsel for the city of Los Angeles.
Tax Dollars for Desal
A recent national survey found a vast majority of Americans believe the potential for a water shortage is a significant issue and support federally funded desalination as a solution. The survey, conducted by Wilson Research Strategies, Inc., was sponsored by the U.S. Desalination Coalition.
A sample of 1,003 adults interviewed this past summer found that 79% of Americans regard water shortages to be a significant issue for them and their families. An equal percentage support desalination as part of a solution.
Only 10% of the respondents were opposed to the use of desalination, while 70% said they favor using federal funding to facilitate the construction and operation of desalination plants.