Worcester Water Filtration Plant (II)

Environmental Science students visit the city’s water filtration plant in Holden, MA. Pictures above display i) the role that computers play in monitoring and managing each treatment step, ii) plant manager Bob Hoyt fielding a question from upper school science teacher ,Paul Elkins – in the room for coagulation (fast mixing of aluminum sulfate and cationic polymer binds to debris, forming flocs, which after going through slow mixing, or flocculation, will be filtered out by the top layer of the direct filtration beds (comprised of 5 feet coal, 1 foot sand, 1 foot gravel) and de-ozonation (excess ozone needs to be converted back to O2 before being released outside)- and iii) students peering over the direct filtration beds (filtering water at a rate of about 6 gallons/sf/minute). Typically, the plant reaches it annual maximum during the summer, with 32+ MGD, well below its maximum capacity of 50 +MGD. If and when a water main breaks, the plant will have to compensate for the water pressure drop and lost water by increasing filtration rates by a few MGD. The city is working to mitigate the contamination threat from “cross connections” which is when non-potable water (contaminated with pesticides, chlorine, industrial materials, etc.) back-flows into the water distribution systems due to negative pressure. For more information click on the Water page above and previous water post