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|10/18/2017 ||Email this article Print this article |
|DeWitt OKs studies on
cleaning up wastewater|
Nutrient reduction part of water quality issue state, cities are facing
By Tom Pantera
It's uncertain how it will be done, or how much it will cost, but DeWitt has taken the first, early steps to do its part for a big issue for Iowa: cutting nutrient levels in wastewater.
The city isn't exactly taking that step voluntarily, however; it's part of the deal in renewing its state permit, through the Department of Natural Resources, to operate the city wastewater plant.
The DeWitt City Council started the process Monday when it approved paying its engineering firm, IIW, $52,000 for a study that will come up with a nutrient reduction strategy.
That is one of three such studies that will have to be done, and council members approved contracts for all three. The others include $33,750 for a strategy to improve disinfection of wastewater; and $44,900 for a strategy to meet new, lower levels of metals in wastewater.
Aside from being the most expensive of the three studies, the nutrient study addresses what has become a major issue statewide, pitting agricultural interests against environmentalists.
Nutrients occur naturally in water, and can be aggravated by agricultural runoff, primarily from fertilizer.
The three main ones are nitrogen, phosphorus, and oxygen. Too much of any of those will aggravate algal blooms in water, which can suffocate aquatic wildlife.
Geoff Blandin of IIW, the city's engineering consultant, said reducing levels of any of those three substances involves mechanical fixes to its current methods, combined with biological processes at the city wastewater plant.
Basically, outflow from the city's wastewater plant is oxygenated, which reduces nitrogen and phosphorus, Blandin said. But once that's done, other measures have to be taken to reduce higher-than-allowed amounts of oxygen left in the water.
local water rates
Under its latest DNR permit to operate the wastewater plant, the city has until the end of 2018 to come up with a plan that includes various options to reduce those nutrients. That plan also will include the costs of the various options and how much each would increase sewage treatment rates paid by property owners. The DNR then signs off on the city's chosen plan, Blandin said.
Clinton is considered a leader in nutrient reduction at its wastewater plant, but Iowa's 18th largest city reportedly has the second- or third-highest municipal water rate in the state.
Meeting new standards for disinfection might involve modifications to DeWitt's wastewater treatment plant, while meeting the standards for metals probably would not, City Administrator Steve Lindner told council members Monday. Reducing metals in wastewater is more a matter of working with the industries in town that use those metals to contain them before they get into the city's sewer system.
In other action Monday, council members:
Gave $500 to the DeWitt Lego League for a public information project on water conservation.
Turned down a request from property owner Ellen Mayberry to pay half the cost of mud-jacking to level the sidewalk in front of 505 Sixth Ave. That sidewalk has sunk due to private utility lines run underneath. Lindner had recommended against the request because nothing the city has done caused the problem.
Approved a change order adding $20,151 to the cost of the West Side Trail Project to move part of the trail 20 feet to the north. The change was made at the request of property owners, who will in turn grant an easement to run the trail across their property.
Approved second reading of an ordinance that will close all DeWitt parks at dusk. All but Westbrook Park currently close at 11 p.m.
Approved closure of the 1200 block of Fourth Avenue from 5 to 11 p.m. Oct. 2 for a neighborhood block party.
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