The Water Cycle: MWRA Style

Have you ever wondered where the water from your kitchen sink comes from? Or what happens once you flush the toilet? Believe it or not, the water in your faucets, down your drains, and even in your toilet bowl are significant parts of a complex and effective water system run by the Massachusetts Water Resources Authority (MWRA).

The MWRA supplies water to local water departments across the state. The water cycle begins in the Quabbin Reservoir and the Wachusett Reservoir. Water from rain and snow form streams, which flow into these reservoirs. As the water flows towards the reservoirs, it encounters various rocks and plants that can help clean the water. The water in the reservoirs and in the streams is kept clean because of the watersheds that protect it and because of constant examination and daily patrol.

For Metro West and Metro Boston communities, the water from these reservoirs travels through the Cosgrove or Wachusett Aqueduct. It reaches the newly built John J. Carroll Water Treatment Plant at Walnut Hill in Marlborough. Here, the water goes through vigorous treatment to ensure cleanliness. After being disinfected with ozone, the water is instilled with chloramines, which protect the water from contamination from pipes. Then, sodium bicarbonate is added to reduce the acidity of the water; this reduces the possibility of metal particles from pipes from dissolving into the water. As a final touch, fluoride, like the kind in your dentist's office, is included in the water for healthy teeth. After being thoroughly treated, the water goes through the Metro West Water Supply Tunnel. It is stored in covered tanks before passing through pipes and distribution mains to reach your community.

In the Chicopee Valley, water enters the Ware Water Treatment Facility in Ware. Water here also goes through a very thorough treatment process. The water is first disinfected with chlorine. Then, chloramines are added to it. The Chicopee Valley Aqueduct carries the water to each community, where the water will to be further treated. For example, the water is treated to prevent the dissolving of metal particles from pipes.
Pipes around your neighborhood bring the water into your very own house. Although there is a long and complicated process of treatment, the MWRA's water cycle works efficiently and simply. You can demonstrate this just by turning on the sink!

Now that you know how the water gets to your house, the question now is what happens to the water after it leaves your house. Once the water goes down the drain, it enters a whole different world of treatment. The water goes down the pipes in your house to your community's local sewer and then to MWRA' s interceptor sewers. When water is being collected, there are screens that prevent large objects like bricks from flowing along with the water. Pumps do their jobs accordingly and pump the sewage through tunnels under the Boston Harbor. The water is transported to treatment plants, like the Deer Island Treatment Plant. Here, the water is treated in three steps. First, in the preliminary treatment, mud and sand are separated from the water and settle in a tank called the grit chamber. The things that are in the grit chamber are fittingly called grit and screenings. These are landfilled. Some of the landfills that you see may be there because of water and the MWRA's water cycle - imagine that the next time you walk down the street! After the preliminary treatment, the primary treatment, in which the sewage flows into primary settling tanks, is performed. 60% of the solids in the sewage settle out in these tanks as a mix of sludge and water. The sludge from this and from the primary treatment is treated in sludge digesters. The sludge is heated to kill harmful bacteria and reduce the volume. The sludge is transported to a pelletizing plant in Quincy by a barge. Next, oxygen is added to the wastewater in the secondary treatment. The oxygen helps microorganisms grow faster. The microbes are important, because they consume most of the waste before settling to the bottom of the tank. Most, 80%-90%, of human waste, solids, and toxic chemicals are removed. Toxic chemicals pose a serious threat to the environment if too much enters the sewers. Even everyday items, like paints and household cleaners, can contain toxics. Try your best to choose less toxic alternatives and thereby helping the MWRA system and the environment. Finally, the wastewater is disinfected and travels as a stream called effluent. It goes in the Outfall Tunnel, a 9- mile tunnel below the ocean floor. Towards the end of the tunnel, there are release points called "diffusers" that allow the wastewater to mix and be diluted. The water reaches the end of the MWRA water cycle when it is finally released into the Massachusetts Bay.

The MWRA water system passes through many paths, from the rainwater of the skies to the shores of the sea. Next time you take a bath or wash the dishes, remember what a major role water from the MWRA plays in your life. Think about and appreciate the water cycle - MWRA style, that is.

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