Water Sustainability Programs
The Facility Service group is taking the following actions to reduce the environmental impact of Baylor College of Medicine's operations:
This initiative began as a project to collect reject water from reverse osmosis water purifying systems and pump it to the cooling tower for evaporation as part of the air conditioning system. Started in 1989, the system has been expanded throughout the campus to collect drain water from ice machines, scientific lasers, air handling units, rain water, roof drains, and drinking fountains. We are currently processing and recycling over 30,000,000 gallons of water a year using this system for a savings of more than $140,000 per year.
The College also uses the cooling tower blow down water to cool boiler blow down water and high temperature cage washer water discharge. In the case of both the cooling tower and boilers the evaporation of water as a natural part of the process causes the amount of solids to build up in the system and a portion of this high solid water must be drained from the system to keep the chemical-solid ratio in balance.
Cooling Tower Water Filter
As part of the HVAC process, the cooling towers evaporate water to provide cooling for the air conditioning of the campus. The cooling tower system is uses direct contact between air and water to facilitate the evaporation process. As a result of the evaporation process the pure water is removed from the system and all the water and airborne solids and impurities remain in the cooling water system. This dirt accumulation in the system remains in suspension and precipitates out in the basin of the cooling towers. The dirt particles become a home to bacteria and other microscopic organisms (often called "slime") that grow and look for opportunities to attach themselves to the walls of the air conditioning units and reduce the heat transfer efficiency of the air conditioning process. The cooling tower filter removes the dirt particles and the biomass associated with the particles. By removing the dirt and biomass from the system we are increasing the heat transfer efficiency of the system and we are reducing the amount of chemicals we have to inject into the system to kill the bacteria.
The cooling tower water filters save water by making sure that the cooling tower blow down water is very high in solids, minimizing the number of gallons of water necessary to maintain the water-solid system balance, and it minimizes the amount of the water treatment chemicals discarded to the environment by virtue of the reduced volume of water discarded. These systems have a pay back on investment of one to two years and have a life of 10-15 years.
Kitchen Exhaust Air Scrubber Water Recycling
This program recycles water that was previously being disposed of after just one use. Our cafeteria uses water injected exhaust fans to minimize the amount of particulate (grease particles) and odor that is discharged from our cafeteria grilling operations. The operational process is such that the water is injected as a mist into the exhaust stream. The injected water then "captures" any particles and removes them from the air stream. This water and particle mixture then drains from the system before the air is exhausted to the outside air. The installation had the water / particle mixture routed immediately to the floor drain in the mechanical room. We installed a tank with a float controlled make up water line to create a recalculating water system. Now the discharge flows into a collection tank where we daily introduce a degreaser and the water level is maintained by a simple float valve. Water from this collection tank is used to supply the mist to the exhaust system. We drain this system once a week to minimize grease buildup. This project saves over 1,500 gallons of water each day or 375,000 gallons of water and approximately $3,000 each year.