Top 10 Water Management Techniques
EPA's Sustainable Facilities Practices Branch developed the following list of top 10 water management techniques that have proven helpful in managing water use at facilities throughout the Agency.
- Optimize Cooling Tower
- Upgrade Sanitary Fixtures (High-Efficiency Toilets and Urinals, Faucet Aerators)
- Eliminate Single-Pass Cooling
- Incorporate Landscape Irrigation/Xeriscaping
- Reduce Steam Sterilizer Tempering Water Use
- Reuse Culture Water
- Control Reverse Osmosis System Operation
- Recover Rooftop Rainwater
- Recover Air Handler Condensate
The process of metering, measuring, and managing laboratory facilities is essential for effective water management. Metering and measuring help in analyzing a facility's water usage, and proper management of mechanical equipment results in greater water efficiency. Making sure that the equipment is run correctly and maintained properly is the key to preventing excess water usage through leaks and malfunctioning mechanical equipment.
- In FY 2006, facility managers at EPA's Office of Research and Development (ORD) in Athens, Georgia, noticed that the facility's water bill had doubled over a two-month period of time. By closely monitoring the facility's water use, they were able to detect the serious leak—located in an underground pipe—and quickly fixed the problem.
- Water metering at the Region 8 Laboratory in Golden, Colorado, indicated that irrigation accounted for more than 50 percent of the facility's total water use. Facility managers determined that an excessive amount of water was being used, and this led to the push for the facility’s xeriscaping project.
Cooling towers provide a vital source of cooling for laboratories, but they are also large consumers of water. Cooling tower operations can be optimized by carefully controlling the ratio of the quantity of water evaporated to the quantity of water discharged (blowdown). The quantity of water evaporated is a function of the cooling demand. The quantity of blowdown should be controlled using an automated conductivity controller, and by maintaining proper cooling tower water chemistry. The ratio of evaporation to blowdown is called the cycles of concentration. If possible, cooling towers should be operated at six or more cycles of concentration for maximum water-efficiency. In addition, metering the quantity of water put into and discharged from the cooling tower provides information that helps to better manage the efficiency of the tower.
- In FY 2003, the Environmental Science Center in Fort Meade, Maryland, saved 530,000 gallons of water and approximately $1,800 by reducing its cooling tower blowdown.
Prior to the 1990s, when the government established federal water-efficiency standards, most EPA facilities were outfitted with inefficient sanitary fixtures, such as toilets that used 3.5 gallons per flush (gpf). Several EPA laboratories have since received water-efficiency upgrades, including new toilets with efficient flow rates of 1.6 gpf, urinals with 1.0 gpf rates or below, and even waterless urinals in some men’s bathrooms. If you have old sanitary fixtures, consider an upgrade. In addition, many lavatory faucets that flow at 2.0 gpm or more can be retrofitted with spout-end flow control devices that limit flow to 0.5 gpm. These devices provide a comfortable spray for washing and rinsing hands, and they save a significant amount of water.
- High efficiency plumbing fixtures, along with other water efficiency upgrades, helped the Mid-Continent Ecology Division Laboratory in Duluth, Minnesota, reduce its water use by nearly 60 percent from the FY 2000 baseline.
- Since April 2004, the Atlantic Ecology Division Laboratory in Narragansett, Rhode Island, has installed 11 new waterless urinals and one high efficiency urinal that flushes at 0.125 gpf. Lavatory faucets have been retrofit to flow at either 0.375 or 0.875 gpm, depending on faucet configuration. Showerheads have be replaced with ones rated at 1.25 gpm with superior results.
- In April 2008, the Ecosystems Research Division Laboratory in Athens, Georgia retrofit two restrooms with 1.28 gpf high efficiency toilets and 0.125 gpf high efficiency urinals. In addition, all lavatory faucets were converted to 0.5 gpm maximum flow.
Single-pass cooling uses a continuous flow of water that is circulated once through the system for cooling purposes and is then disposed of down the drain.
- In FY 2001, the National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, Michigan, replaced its single-pass cooling system with an upgraded cooling plant involving a recirculated chilled water loop. This upgrade helped NVFEL reduce its water consumption by 80 percent, saving the laboratory 24.8 million gallons of water and $235,000 annually.
- In FY 2004, the Western Ecology Division Laboratory in Corvallis, Oregon, installed a closed-loop system that uses a recycled chilled glycol solution instead of water to cool air-conditioning equipment. As a result of this upgrade, the Corvallis laboratory reduced its yearly water consumption by 3.7 million gallons and saved approximately $21,000 annually.
Xeriscaping is a type of landscaping that conserves water by planting native, water-efficient plants rather than water-intensive ones, and utilizes techniques that minimize the need for irrigation. A laboratory can significantly reduce its total water consumption by incorporating xeriscaping techniques, which will help lower or eliminate the demand for irrigation water. Within an existing landscape, irrigation water use can be reduced by 10 to 20 percent by having an irrigation water audit performed (seek out irrigation professionals that are WaterSense® partners) and using a weather-based irrigation controller or soil moisture sensor to control landscape irrigation.
- EPA's Region 8 Laboratory is currently evaluating a xeriscaping project for its grounds in Golden, Colorado. The laboratory anticipates its new landscape will save the facility more than 650,000 gallons per year by using 50 percent less irrigation than the existing turf requires.
Steam sterilizers use cooling water to temper steam condensate discharge from the sterilizer to the laboratory drain. Many older sterilizers discharge a continuous flow of tempering water to the drain, even when it is not needed. This can be prevented with improved operational controls, or by retrofitting the sterilizer with a tempering water control kit.
- The Region 10 Laboratory in Manchester, Washington, changed the operational procedures for sterilizers to maintain them in “standby” rather than “on” mode. This saves an estimated 60,000 gallons of water per sterilizer each year.
- The Western Ecology Division Laboratory in Corvallis, Oregon, installed tempering water control valves on its sterilizer, which allows water to flow only when the sterilizers are operated. This saves approximately 1.5 million gallons of water and between $6,000 to $9,000 annually.
- The Ecosystems Research Division Laboratory in Athens, Georgia replaced an older sterilizer unit with a new unit with efficient tempering water control. This upgrade saves an estimated 500,000 gallons per year.
Several EPA laboratories require water for aquatic culture research. In some cases, culture water is pumped into laboratory specimen tanks from local bodies of water, such as lakes or bays, but then might be discharged into the sewer after use.
- The Mid-Continent Ecology Division Laboratory in Duluth, Minnesota, uses approximately 35 to 40 gallons per minute of Lake Superior water for its wet laboratory. The lab installed an aquatic culture water filtration system that diverts this water back into the lake instead of the sewer system.
Up to 10 percent of a laboratory’s water consumption can be related to the multi-step process of generating deionized (DI) water through reverse osmosis (RO). Water savings can be achieved by carefully regulating DI generation rates to meet laboratory demand. Avoid producing excess DI water that overflows to drains.
- In FY 2003, EPA's Environmental Science Center (ESC) in Fort Meade, Maryland, conserved approximately 1.5 million gallons of water and saved more than $5,000 by reducing DI/RO system operation from 24 hours per day to 12 hours per day.
Rooftop recovery systems capture rainwater from the roof and redirect it to a storage tank. This cache of water can then be used for various purposes throughout the facility, such as flushing toilets, supplying cooling towers, and irrigating the landscape.
The Region 7 Science and Technology Center in Kansas City, Kansas, has incorporated a state-of-the-art rooftop rainwater recovery system in its new facility. The design consists of a 1,500-gallon underground settling tank and a 10,000-gallon holding tank. This system has the potential to save the laboratory more than 500,000 gallons of water per year.
The normal operation of air conditioning equipment in warm, humid climates produces condensate water from the cooling coils. Rather than draining this water into the sewer system, some EPA laboratories are capturing this water for use in cooling towers and other various applications.
- EPA's Environmental Services Branch Laboratory in Houston, Texas, implemented a project that incorporates air handler condensate recovery at a cost of less than $6,000. This project saved the laboratory $20,000 over the past six years and also saves approximately 832,000 gallons of water annually.
- The Region 4 Science and Ecosystem Support Division Laboratory in Athens, Georgia completed a project in 2008 to capture condensate from three rooftop air handlers and route it to the facility cooling tower. The system is anticipated to save 300,000 gallons per year.
For more information on water saving best practices, please see the resources available from the Federal Energy Management Program (FEMP).