Drought leads to woes with water clarity in Elgin
By Mike Danahey firstname.lastname@example.org September 5, 2012 8:26PM
A 30 inch pipe brings water from the Fox River to the Riverside Treatment plant in Elgin. From this point, it takes 24 hours, on average, before it hits the consumers tap. | Sun-Times Media File
Updated: October 7, 2012 8:00AM
ELGIN — Because of how Elgin draws water from the Fox River, the city has not needed to put any usage restrictions in place during this summer’s drought. However, the drought means that staffers at the Riverside Treatment Plant have been fighting issues with water clarity.
Regular rainfall provides a river with a fresh inflow that reduces the incidence of solids of all sorts in the water. During a drought, the quality of the water is reduced and it can become turbid, which has been the case in Elgin.
According to the federal Environmental Protection Agency website, “Turbidity is a measure of water clarity — how much the material suspended in water decreases the passage of light through the water.”
Those materials usually are very small and include soil, algae and microbes. Sources of turbidity include erosion, waste discharge, urban runoff, erosion, stream banks, large numbers of bottom feeders such as carp stirring up bottom sediments, and excessive algae growth.
For human consumption, the Illinois Environmental Protection Agency has turbidity regulations that apply to both a plant’s output to homes and businesses as well as to the filters used to remove particulates.
Water Director Kyla Jacobsen said that sometime over this past weekend, the Riverside plant exceeded IEPA standards for individual water treatment filters on two filters. The matter was immediately rectified and reported to the state agency, Jacobsen said.
However, overall plant output turbidity levels have remained within acceptable ranges: “At no time was total water output compromised,” Jacobsen said.
To battle the turbidity trouble, the water department has been using chemical treatments and back-washing the plant’s filters. Jacobsen said the process involves using alum and small doses of polymer, which make the tiny particulates stick together, then settle out of the water, either at the bottom of a basin or in the filters.
The back-washing of the filters apparently led to drainage problems, and the treatment plant’s wash-water recovery basins intermittently overflowed and sent water down the road toward the Fox River. That stopped over the weekend, Jacobsen said.
Jacobsen explained that water from the plant not put into the system normally goes to lagoons, then back into the Fox. The water in question went from the wash basins to the street then to the river.
Jacobsen said turbidity has been an issue this year at least since March and appears to have peaked in August. To help rectify it, the area will need considerably more rain, she said. Too much rain all at once, though, can also lead to turbidity issues, stirring up particulates, as can a lot of boats, she noted.
To deal with the turbidity, Jacobsen estimated the water department used about twice as much in treatment chemicals as it did last year.
While the low river levels led to turbidity issues for the city’s water, it can also mean trouble for the aquatic ecosystem. According to the EPA website, “Higher turbidity increases water temperatures because suspended particles absorb more heat.” That reduces the concentration of dissolved oxygen in the water. Higher turbidity also reduces the amount of light penetrating the water, which reduces photosynthesis and the production of dissolved oxygen.
“Suspended materials can clog fish gills, reducing resistance to disease in fish, lowering growth rates, and affecting egg and larval development. As the particles settle, they can blanket the stream bottom, especially in slower waters, and smother fish eggs and benthic macroinvertebrates,” the EPA website states.
As for why the city has no watering bans, its system is such that, as Mayor Dave Kaptain has noted, for every gallon the city takes out of the Fox, it puts back three-quarters of a gallon.
Elgin also is part of the Fox River Water Reclamation District, which provides wastewater treatment to about 150,000 people within Elgin, South Elgin, West Dundee and portions of Sleepy Hollow, Streamwood, Hoffman Estates and unincorporated St. Charles Township, and FRWRD puts its treated wastewater into the river. Jacobsen has noted that for every 20 gallons the city uses from the river, FRWRD puts 23 to 25 gallons back in. Most of the other towns get their water originally from wells.
While no one in Elgin went thirsty, the hot and dry conditions did lead to some unusually high uses of water.
Sources said the Bowes Creek Country Club was using as much as 600,000 gallons of water a day during the height of the heat to keep the city-owned course green. The country club draws waters from its own wells.
And Sherman Hospital had to add 4.58 million gallons of water to the 15-acre, energy-producing geothermal lake on its campus. For that, the hospital employed a nearby fire hydrant and used a special meter hooked up to it for billing and monitoring purposes.