BMP #12 - Laboratory/Medical Equipment
Background
Equipment used in hospitals and laboratories can use significant amounts of water, but also offer the opportunity for substantial water savings by making a few small changes to how and when the water is used by the equipment. The Environmental Protection Agency (EPA) and the Department of Energy (DOE) recognize the importance of incorporating water efficiency products and practices in laboratory settings. These Agencies have teamed up under a program called Laboratories for the 21st Century (Labs 21) to provide architects, engineers, and facility managers with information about technologies and practices that can be used to create and maintain sustainable, high-efficiency laboratories. Focusing on reducing water use from equipment such as water treatment systems, sterilization/disinfection systems, photographic and x-ray equipment, vacuum systems, glassware washers, and vivarium equipment such as automatic animal watering systems and cage and rack washers can go a long way towards helping Federal facilities achieve water efficiency goals.
For more information on this and other FEMP Water Efficiency Best Management Practices, please see the resources section.
Operation and Maintenance Options
- Establish a user-friendly method to report leaks and fix them immediately.
- When performing maintenance replace worn parts and adjust mechanisms to ensure that the water consumed continues to meet manufacturers' guidance.
- Encourage cleaning or custodial crews to report problems.
- Shut off units that are not in use, or install an automatic shut-off feature if it does not interfere with the unit's normal operation.
- Check solenoids or automatic shut-off valves regularly to ensure that they are working properly. Verify that water is not flowing when equipment is in stand-by mode.
- Install a pressure-reducing device on equipment that does not require high-pressure. Lowering the pressure can reduce water use.
- Set equipment to the minimum flow rates acceptable or recommended by the manufacturer and post signs nearby equipment to increase employee awareness and discourage tampering with equipment flow rate.
- Run glassware washers only when full, use newer, cleaner rinsing detergents, and reduce the number of rinse cycles whenever possible.
Retrofit Options/Replacement Options
Water Purification Systems
- Evaluate the laboratory's requirements for high-quality water, including the total volume and the rate at which it will be needed, so that the system can be properly designed and sized.
- Choose systems with a higher recovery rate - the ratio of filtered purified water to the volume of feed water. Some proprietary systems claim recovery rates up to 95 percent. Conventional reverse osmosis systems have recovery rates between 50 and 75 percent.
- Consider reusing concentrate produced by reverse osmosis treatment systems for non-potable applications such as in bathroom commodes. Water quality should be monitored to avoid fouling other systems.
- Determine the quality of water required in each application; use the lowest appropriate level of quality to guide the system design. For example, reverse osmosis units should only be used in processes that require very pure water.
- Evaluate the quality of the water supply for a period of time before the water purification system is designed. This evaluation allows designers to accurately characterize the quality of the water supply and helps them determine the best method for attaining the quality level required.
Disinfection/Sterilization Systems
- Replace older inefficient equipment with new equipment only that is designed to recirculate water or allows the flow to be turned off when the unit is not in use, or both.
- If purchasing new equipment is not feasible, consider purchasing a water efficiency retrofit kit; many are now available for older units. They reduce water use by either controlling the flow of tempering water or by replacing the venturi mechanism for drawing a vacuum. Tempering kits sense the discharge water temperature and allow tempering water to flow only as needed.
- Install a small expansion tank instead of using water to cool steam for discharge to the sewer. Check with the manufacturer to make sure this will not interfere with the unit's normal operation.
- Use high-quality steam for improved efficiency.
- Use uncontaminated, noncontact steam condensate and cooling water as make-up for non-potable uses, such as in cooling towers and boilers.
Photographic and X-Ray Equipment
- Replace older equipment with digital x-ray and photography equipment and computerized printing. If transitioning to digital equipment is not feasible, look for models with a squeegee that removes excess chemicals from the film. The squeegee can reduce chemical carryover and reduce the amount of water needed for the wash cycle.
- If the purchase of new equipment is not feasible, adjust the film processor flow to the minimum acceptable rate. If necessary install a control valve and flow meter in the supply line to monitor flow rate.
- Recycle rinse bath effluent as make-up for the developer/fixer solution.
Vacuum Systems
- Install a laboratory vacuum system or use small electric vacuum pumps instead of employing faucet-based aspirators to create a siphon vacuum source.
Glassware Washers
- Replace older inefficient glassware washers with new dishwashers that use less water. Choose models that allow the operator to select the number of rinse cycles or that can reuse final rinse water as wash water for the following load.
- Install a water recycling system for glassware washer wastewater.
Vivarium Equipment
- Replace older inefficient cage and rack washers with new more efficient models. Look for models that recycle water through four stages of cleaning using a counter-current rinsing process. In counter-current rinsing, the cleanest water is used only for the final rinsing stage; water for early rinsing tasks (in which the quality of rinse water is not as important) is water that was previously used in the later stages of rinsing operations.
- Retrofit existing cage and rack washer to make use of counter-current flow system to reuse final rinse water from one cage-washing cycle in earlier rinses in the next washing cycle.
- Use tunnel washers for small cage cleaning operations.
- Sterilize and recirculate water used in automatic animal watering systems instead of discharging water to the drain. Where water cannot be recycled for drinking due to purity concerns consider using in other non-potable applications such as cooling water make-up, or for cleaning cage racks and washing down animal rooms.
Laboratory and Medical Equipment Resources
US Environmental Protection Agency and Department of Energy. Labs for the 21st Century. (PDF 473 KB). Download Adobe Reader.
U.S. Department of Energy. Case Study - Veteran Affairs Hospital.