What’s going down the drain can be money. Energy conservation through reduced water consumption and lower cycle temperatures don’t mean less sterile.
Each time we fill our car’s fuel tank or pay our electricity, gas, or water bill, we are constantly reminded of the continued rising costs of energy and natural resources, with no end in sight. In our homes, we may consider reducing energy costs by converting to a high efficiency HVAC unit, utilizing state-of-the-art, low-energy burners, pumps, and operational modes. The effort may be further applied by reducing hot water temperatures and by raising air conditioning or lowering home heat temperatures. We may even try out the hybrid or alternate fuel-burning cars and trucks.
What about energy conservation in the workplace? Laboratories, in general, are large consumers of utilities. This is in part due to the nature of the industry. The requirement of high-level cleaning, disinfection, and sterilization means the use of specialized equipment and standard operating procedures. These large pieces of equipment (rack washers, tunnel washers, autoclaves, and others) consume large amounts of water and other utilities to perform their tasks.
Many university officials have been given the directive to investigate and implement energy efficiency improvement programs to reduce the demand on all utilities wherever possible. Considerations from recycled vs. raw materials, energy reclamation, and energy efficient systems are all strategies being considered during the renovation or design of their facilities. Research facilities in California, Oregon, Nevada, and several others are especially sensitive to the need of assessing the multiple benefits of integrated water-energy efficiency measures.
Life science cage and rack washing systems have traditionally been a large consumer of both water and heat energy resources. Much like a household dishwasher, the traditional life science cage and rack washer would be programmed with a cleaning cycle consisting of a pre-rinse, alkaline wash, rinse, and a final disinfection rinse phase. For each of these phases, the unit would fill the sump (40–60 gallons), heat and recirculate the water through a spray system, and discard the water to drain at the end of the phase. Additionally, many washers are provided with an optional cold water discharge cool-down system. With this option, cold water is injected into the hot effluent as the unit drains, cooling the wastewater to an acceptable drain temperature. The cold water consumption for this process could be as much as 40–60 gallons per phase, thus doubling the total consumption of domestic water. A cycle could consume as much as 320–480 gallons of water per cycle, or upwards of 8,600 gallons per day, half of which required energy to heat it!
Today, there are several alternatives to the “traditional” washer and cycle parameters. Several equipment manufacturers have recently introduced new washer models with improved features and options to better utilize both utility and water efficiency throughout the cleaning and disinfection cycle process. These highly efficient washers now can provide the same cleaning and disinfection with water con-sumptions of less than 50 gallons per cycle and, with additional options, could be as low as 12 gallons per cycle. Other areas of energy and water savings could be offered as:
• Higher-efficiency motors and transformers
• Redefinition of cycle parameters
• Reduction of sump sizes
• Reutilization of wash waters
• Reuse of waters
• Reduced heating temperatures of non-temperature sensitive phases of the cycle
• Drain-water heat recovery systems to preheat in-coming to the water heater
• HVAC heat recovery