Raul Varela was hired by MIT 10 years ago in an effort to conserve water at MIT. They looked at much of the water use on campus, and analyzed projects and their payback time. Projects that had payback periods of 2-3 years are near completion. The next set of conservation efforts will pay back in roughly 5-6 years, and have not been implemented yet. Included in this project are some of the efforts that have been made thus far.
All new buildings in the state of Massachusetts cannot contain toilets with a capacity greater than 1.5 gal. In 1999 water conservation program took this farther by installing low flow toilets in all of the bathrooms on campus. The traditional toilets before flushed 6 gallons of water per flush, so these new installations drastically reduced the amount of water used on campus. Also, the team retrofitted urinal flushometers.
Along with installing new toilets across campus, the water conservation team also installed faucet aerators in bathroom and kitchen sinks. This decreased the amount of water going through the faucets without compromising the pressure.
These two efforts resulted in water savings of 11,802,922 gal/year in the residential buildings.
New high efficiency washing machines were installed in dorms in 2002. These use half the amount of water traditional washing machines use.
Reverse Osmosis (R.O.) water is used for many laboratory experiments. To make the R.O. water, each laboratory has its own R.O. water system that is very water intensive. In 1999, the water conservation program recirculated the R.O. reject water in buildings E17 and E25. The R.O. purification process is very wasteful; for every gallon of R.O. water made, 9 more gallons are wasted. To conserve water, the system is looped so that the discarded water is recycled back into the machine, and processed again. This process has been implemented in building E17, E25. By closing this loop, 146,600 gallons/year of water was saved.
Another R.O. related conservation effort is to use the discarded water as non-potable water in other laboratories. Uses for non-potable water include the taps within the laboratories or as cooling water for the autoclaves. This water is also used to flush toilets. This process has been implemented in buildings 68 and 39, saving the institute 1, 446,000 gallons/year.
The efficiency of R.O. systems have been increasing in the recent years. While these new systems are more expensive, they provide more R.O. water for the amount of water being put through. Building 39 is currently upgrading their R.O. system, which will save the institute an estimated 1,985,695 gal/year.
Various facilities and laboratories on campus need water to cool excess energy and heat that are produced. The water previously was used once before it was discarded. The conservation effort has re-piped these systems in buildings 12, 26, and E23 to chilled water. This water is then used throughout the rest of campus as gray-water, providing non-potable water for other facilities. This has saved the institute 1,640,000 gal/water.
Autoclaves use the steam of water to sterilize and heat-treat laboratory equipment in many labs. To produce the steam, water is raised to extremely high temperatures. This leftover water is condensed at very high temperatures. However, water cannot be discharged at 180F. Thus, chilled water is used to mix with the hot water so the final water temperature is at 120F. In the past, the chilled water is run continuously through the system, regardless of whether or not the autoclave was on and producing hot water. The system has been redesigned and programmed so that the chilled water only enters when needed.
These water tempering limiters has been implemented in buildings E17 and E56, saving the institute 976,064 gal/year. It is also being implemented in buildings 68, E18 and E25 saving the institute an estimated 3,360,000 gal/year.
All the academic building bathrooms on campus were replaced with low-flush toilets in 1999. This resulted in water savings of 18,700,000 gal/year
The chilled water system not only represents an energy efficient way of producing cold water, but also serves to conserve water. Before the system was introduced some of the laboratories used once through cooling equipment. The chilled water system uses a closed loop system to deliver cool water to the laboratories, which is then delivered back to the condensers to be cooled where some water is lost. This chilled water system has saved MIT an estimated 8,000,000 gallons of water per year.
In 2001, MIT installed a new irrigation system at Brigg's Field and Killian Court. This new system is connected to a satellite controller behind Johnson Athletic center. At this location, probes look at the evapotranspiration of the soil. The irrigation system only goes on if the evaportranspiration of the soil falls below a certain point. The system also contains a cup that collects rainfall. If this cup gets filled to a certain capacity, the sprinkling system gets shut off.
This new systems also have a separate water meter for irrigation. Previous water meters only read one value for all water usage in a building, regardless of its use. This new meter will allow the institute to have a more accurate understanding of how much water is used for irrigation.
When the water conservation effort at MIT started around 1990, the water usage excluding cogen was around 400,000,000 gallons per year. The water usage for 2001 was 240,000,000 gallons per year. This does not include data for the two cogeneration plants on campus. This 40% saving in water has saved the institute roughly $1,000,000 in its annual water bills.
Raul Varela's efforts have not gone unnoticed. In 1995, he received the Facilitiees Management Excellence Award (FAME), issued by the American Institute of Plant Engineers for effective water reclamation and reuse in a campus building. At MIT, Raul also received an environmental award for his water conservation efforts.
One of the only shortcomings of the water conservation at MIT is that it has gone largely unnoticed by the students. Those who witnessed the upgrading of all the toilets have graduated, and almost no one knows about the water conservation efforts in the academic laboratories and facilities. If students are made aware of MIT's attempts to save water, they may make more of an initiative on their own to do the same.
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