Utility Committee Agenda and Packet 2020 05 12

Home Browse Search

Data increasingly guides water and wastewater treatment operating decisions. Numbers replace sight, sound, smell and dosing-and- retention-time guidance handed down from old timers. Plants and distribution and collections systems substitute calculations and facts for guesses and gut feelings. A case in point is Louisville, Colorado, which has two water treatment plants and eight full-time operators for its population of 20,000-plus. The city, between Denver and Boulder, was founded as a coal mining town in the late 1870s. It became a bedroom suburb in the 1950s when the coal played out and the need for living space continued to grow. Louisville’s Sid Copeland Water Treatment Plant (North) can produce 8 mgd, and the Howard Berry Water Treatment Plant (South) can produce 5 mgd. Both are conventional dual-media sand filter plants using alum as the primary coagulant and chlorine dioxide as a preoxidant for manganese reduction and taste and odor control. Both plants have undergone major construction and improvements over the last two years. Greg Venette, chief water plant operator, oversees both. “We recently completed construction of a new $3.2 million potable water pump station that had been on the books for 10 years and replaced an old pump station that had been in service since the 1970s,” Venette says. The old pump station could deliver to only one of three distribution zones in the city: the high zone. “With the new pump station, we added three pumps that can pump directly to the midzone,” Venette says. “Previously, both plants would have to be operating to support all three zones, or valves in the distribution sys- tem would have to be adjusted manually every day.” BANDAGE FIXES FIXED The old pump station was at about the same elevation as the storage tank it was built to pump to. It was a bad design made worse by bandage-type fixes applied over time. Operators Bob Carra, Glen Siedenburg and Herb Trickle are among those who kept things running even when times were tough. “Lines would air-lock, and pumps would rattle. It was scary,” Venette says. “And it was almost impossible to find spare parts for the pumps.” The new pump station, completed in May 2018, includes modern Aurora split- case centrifugal pumps (Pentair), variable-frequency drives and monitoring equipment. “We also built in pressure relief valves that allow us to download water to different pressure zones in town and back-feed storage tanks,” Ven- ette observes. The new system provides water to a pressure zone that never existed before. It can send water throughout the city in multiple ways and configu- rations. The project included replacement and upgrade of the emergency generator (Cummins Power Products) and switchgear (Eaton) and the back- wash recycle system. The project engineer, Rob Anderson with Mott MacDonald, also figured out how to tie waterlines into the plant cost-effectively to help “jump-start” Jocelyn Brink, NEED TITLE, takes water samples from the influent water basins. Changes in the operation have helped the facility rectify problems with algae in the source water. Louisville (Colorado) water treatment plants TREATMENT FACILITIES: 8 mgd Sid Copeland (North Plant); 5 mgd Howard Berry (South Plant) RAW WATER SOURCES: El Dorado Springs; Carter Lake at Colorado-Big Thompson Project RAW WATER STORAGE: 3 reservoirs TREATMENT PROCESSES: Conventional PUMP STATIONS: 2 FINISHED WATER STORAGE: 8.5 million gallons DISINFECTION: North Plant, chlorine gas; South Plant, sodium hypochlorite FACING PAGE: Louisville water plant staff members, from left, NEED NAMES AND TITLES, monitor the facility’s new SCADA system. Prerelease Version – NOT FOR REPRODUCTION 32