August 04, 2021

GMU explores possibility of a new water plant

GREENFIELD — Greenfield Municipal Utilities officials will likely be deciding in the next month or two if they’d like to proceed on building a new water plant in the next four or five years.

The GMU Board of Trustees heard a facilities plan from HR Green representative Heath Picken during a special meeting last Wednesday morning.

While the current plant, located near Lake Greenfield, has mostly kept up with demand and has been upgraded multiple times in its 39-year history, Picken showed that certain recurring themes within the water treatment process could all be improved upon if the plant was modernized even more.

Challenges GMU faces by continuing to operate its plant as it is are in the areas of the firm or hard capacity of water it treats daily and its ability to combat water quality issues such as algae like the water supply was overtaken by in 2018 when a bottled water order had to be issued.

“We are at the peak of our firm treatment capacity with the current plant, we are challenged with potential algae outbreaks annually on the lakes, and much of the treatment equipment is nearing its end of life”, stated GMU General Manager Scott Tonderum.

Picken’s hour-long presentation outlined ways that engineers feel a new plant would help some of these challenges. He started by showing sources of Greenfield’s water supply, which include surface water sources consisting of Lake Greenfield, Nodaway Lake, the Nodaway River, and ground water sources consisting of six shallow alluvial wells.

The current plant takes the water from those sources, pumps to three Trident Package Water Treatment units which combine up-flow clarification and granular activated carbon (GAC) filtration in a packaged, then into a clearwell, and then to a ground storage reservoir where it gets pumped to the elevated storage tank and distribution system.

A main highlight of the proposed system would be an ozone purification process that is designed to give the plant a greater ability to disinfect for various bacteria and viruses. This added process would also improve a taste and smell issue Greenfield has experienced in its water from time to time. Spirit Lake is the only known Iowa community to have a water treatment system with the ozone purification system.

“It’s similar treatment technology, but we’re splitting out the filtration and clarification system, making the clarification sedimentation process a lot more conservative or bullet proof and are adding ozone for the purification process,” Picken said.

The proposed plan would turn the water plant into a two-story facility because of the needed depth of the basins used. Office and laboratory areas of the facility would also be enlarged as part of the proposed plan.

“This new facility would address our needs today and 20 plus years into the future with regards to firm capacity, water quality and the treatment of algae and potential cyanotoxins, improve office and lab space, and give us a concrete building structure that will last 50 years or more into the future,” said Tonderum.

If acted upon, the process for a new water plant would include a pilot study plan conducted through approximately October. The design phase would last well into fall 2022 with bidding early winter 2022. Construction could begin approximately the start of 2023 with completion approximately August 2024.

Greenfield’s current water treatment plant was constructed in 1982. A high service pump room and ground storage tank were added in 1987 with baffling for the ground storage tank constructed in 1994. In 2012, a clarifier and filter rehabilitation was completed and a new generator installed.