Real-Time Data Helps Facility Combat Algae

REAL-TIME DATA HELPS FACILITY COMBAT ALGAE   During the severe drought of 2001 and 2002, the North Jersey District Water Supply Commission pumped more than 32 billion gallons from the Passiac and Ramapo rivers and stored it in the Wanaque Reservoir. While siphoning off the nutrient-rich river water ensured a steady water supply for the people of northern New Jersey, it also increased the likelihood of a serious algae bloom that could make the water supply unsafe.   “At one point, almost the entire reservoir was river water,” noted Dr. Pen C. Tao, water resources management and planning manager/ hydrologist. “With summer temperatures over 90 degrees, it was a good bet that we would have an algae bloom. Algae causes lots of treatment problems, but the most serious is blue-green algae because you can never get rid of it.”

STARVING ALGAE The commission undertook aggressive algae control measures, including “starving” algae by reducing the available nutrients and aerating the water to encourage the growth of harmless blue algae instead of blue-green algae. What the commission then needed was a reliable remote monitoring system to determine whether dangerous levels of algae or other substances were present in the reservoir.   Hydrolab Datasondes were the answer. The commission installed Hydrolab Datasondes at three strategic locations to provide continuous information about the quality of water in the reservoir. The Datasondes test for a host of water quality parameters, including chlorophyll A, a component in aquatic algae, and can transmit data to the commission’s office instantly. Equipped with buoys and remotely controlled pulleys, the Datasondes can obtain water quality data at virtually any depth.   INSTANT DATA “In the past, we did manual profilings once a month—once a week in the hot season—and it would take a couple of days before we could see the data,” said Tao. “Now we can see the data instantly.”   An additional two Datasondes were installed at pumping stations to test the quality of water leaving the reservoir. All five Datasondes are completely automated, have a solar panel power supply and store information in an on-board computer. The data can be downloaded in real-time, and the instruments can be remotely re-programmed to provide the most useful information.

While the threat of an algae bloom was the driving force behind installation of the Datasondes, Tao said the monitoring system also could detect substances that are intentionally introduced into the water supply.