Striving for Net Zero Water

The US Army's Vision for Net Zero

                                                     

Originally focused on net zero energy, the US Army has expanded its vision for net zero bases to now include water and waste. The more immediate goals for the program are the reduction of potable water use by 26 percent by 2015 followed by a 50 percent reduction by 2020. The Army has had to rethink its infrastructure and water use practices from the ground up to be able to reach these goals. The initiative has resulted in greater maintenance policies as well as careful water usage monitoring for every use, from the imbedded water in military equipment to the amount of water used to make a cup of coffee.

The greater attention on water management and saving strategies has lead to the Army investing in a number of infrastructure upgrades and repairs. As an example, the Tobyhanna Army Depot in Pennsylvania installed 54 leak-detection sensors along the main valve stems. The sensors identified six leaks in the system, which led to a daily loss of 90,000 gallons. This lost water accounted for 26 percent of the depot's daily water use. Since then, the repairs have saved $29,459 and roughly 17 million gallons of potable water. The same depot installed water meters to further reduce water loss by another 11,000 gallons per day.

                                                      

Another military base that has made strides toward net zero water is the Oregon Army National Guard at Camp Rilea. Camp Rilea does not rely on a centralized system, but instead on the underground aquifer it sits on. The system in use returns treated water to the underground aquifer to reduce the withdrawal rate of groundwater compared to the replenishment rate. The base uses extensive amounts of treated graywater for non-potable uses to reduce the demand on the aquifer. To further reduce the demand on the aquifer and lessen the amount of water lost due to evaporation, the base is investing in rapid infiltration basins to speed up the treatment process and bring the water back to the aquifer 200 feet below the base.

The base also relies on a water balance analysis to understand what uses demand the most water. The analysis has led the base to invest in water efficient fixtures as well as investigate the use of a weather based control system for watering plants. The system would monitor moisture and precipitation before watering to ensure that water isn't being wasted for watering the surroundings after a rainstorm. Other techniques like this are being developed as the Army seeks to reach its ultimate goal of net zero water, in addition to net zero energy and waste, by 2030.