Water Savings on Tap at Metro as part of Sustainability Lab

August 21st, 2014

New sustainable water treatment systems used to cool underground Metrorail Stations are projected to save Metro millions of gallons of water and hundreds of thousands of dollars annually.

This month, Metro completed one of its first Sustainability Lab pilot projects – the installation of state-of-the-art water treatment systems at seven (7) chiller plants on the Metrorail system. The project will result in an estimated 400,000 gallons of water savings per location annually.


Metro’s Station Cooling and Water Tower System

So how can one project save Metro so much water? The new water treatment system uses real-time monitoring of water quality, detecting minerals, scale and any other bacteria that could result in deterioration to the chiller plant system. As a consequence, water quality adjustments can be made quickly based on the detection of minor variations in water chemistry, instead of testing water samples monthly and setting plants to run until the next test can be completed.

Optimizing the system reduces blow down (automatic discharge of water to prevent corrosion and scaling) that requires the use of make-up water to replenish the cooling system and water lost through evaporation. Using this active management of the cooling system, Metro’s water consumption can be reduced in two areas simultaneously – thereby maximizing the water savings for the Authority.

When combined with two (2) treatment system upgrades completed as part of Metrorail chiller overhauls, cooling tower upgrades have now been completed at nine (9) stations on the Metrorail system (Capitol Heights, Crystal City, Farragut West, Metro Center, Navy Yard-Ballpark, Pentagon City, Potomac Avenue, U Street, and Woodley Park). In water savings alone, the project will save four Olympic size swimming pools of water per year from the seven (7) sites completed as part of the pilot.

This project builds upon staff experience gained from ongoing chiller upgrades at Metrorail stations and further shows the value of sustainable investments in the chiller systems featured in this short video. Once a full evaluation of the pilot project is complete, Metro plans to extend the upgrade to all of the other 46 cooling plants on the system with estimated water savings of 18 million gallons or $700,000 projected as part of the full rollout. This Sustainability Lab pilot investment provides the opportunity to fine tune this larger rollout and supports ongoing progress towards reducing Metro’s water consumption by 20 percent per vehicle mile by 2025, part of Metro’s Sustainability Initiative.

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