WILLMAR -- A nearly $7 million project spread over four to six years is being proposed to improve the quality of water delivered by Willmar Municipal Utilities to its customers. The three-phase project would preserve the viability of the water system infrastructure and replace the core treatment process with biological filtration. The new filtration process would be designed to not only remove iron and manganese -- which had been a problem in Willmar's water two decades ago -- but also remove naturally occurring ammonia (nitrogen) and total organic carbon.
These compounds not only pose significant operational difficulties now but also create byproduct compounds that are currently regulated or will be regulated in the foreseeable future, said Bart Murphy, Willmar Utilities director of water and district heating.
Murphy introduced the proposed project to the Willmar Municipal Utilities Commission on Monday and requested the commission approve a consultant services agreement with Carollo Engineers Inc. of Walnut Creek, Calif., for the first phase of the project in an amount not to exceed $68,606.
Commission President Dave Baker suggested and the commissioners agreed to tour the city's two water plants first and then take action on Murphy's request.
"We need to do due diligence, get into the plants, see what they look like, ask questions,'' Baker said. "I think it's a great idea because I think you're on to something that we definitely need to look into.''
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The utility has two water treatment plants: the southwest plant located on 18th Street Southwest, and the northeast plant located on Lakeland Drive Northeast. Both plants were constructed in 1992 and have been operating about 20 years.
Murphy said there is degradation and worsening of the filter performance over the last five years where the iron and manganese are trapped and backwashed out. Twenty years ago, the primary objective of constructing the treatment plants was to remove iron, which had been a longtime problem.
The water department is trying to deal with compounds in the water that cause operational problems and are subject to current and future regulations, he said.
"We've been working to extend the useful life of these plants,'' said Murphy. "A number of working parts have been replaced. That has been occurring over the last six years. Our goal in this is to maintain the current infrastructure that's viable to take into the future.''
The utility has 17 wells: one at the power plant for emergencies; 10 in the southwest field that tend to be shallower and have more iron and manganese and less ammonia and less carbon; and six wells in the northeast field that are deeper and tend to have less iron and manganese but more ammonia and carbon.
The $146,500 cost of the first phase of the proposed project was budgeted for 2012 and includes the consultant's engineering fee.
The remainder of the phase-one budget includes the nine-month cost of renting from Carollo Engineers a pilot treatment plant, a specially built miniature version of the large-scale equipment that would be installed in the treatment plants.
The pilot plant is critical to the successful implementation of the eventual project, according to Murphy. It forms the basis, through actual demonstration of the treatment process, for the correct design criteria and provides concrete evidence that the process achieves the desired results.
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Murphy proposes the pilot plant be placed in the northeast field.
"We're really after the ammonia and carbon, so we want to make sure we test that water,'' he said.
Murphy said the project should extend the life of the plants by another 20 to 30 years at a minimum cost while reducing operating costs.
The project's second phase of $67,000 in 2013 and $465,000 in 2014 would cover design and bidding. The third phase would include $3.1 million in 2015 and $3.1 million in 2016 to buy and install equipment at each of the two treatment plant buildings.
The total project is estimated at about $6,988,000.
The alternative, he said, is to build completely new treatment plants at an estimated cost exceeding $45 million, with increased operating costs exceeding $800,000 per year.
