Superior orders design of water treatment plant

After considering five options related to the City of Superior municipal water system, the Superior City Council on Monday evening approved hiring an engineering firm to design a water treatment plant. The option is expected to cost about $4.5 million.

Unlike the treatment plant shut down about 50 years ago that used lime and aluminum sulfate to treat the water, the new plant will use a reverse osmosis system.

The City of Superior uses on average 750 to 800 thousand gallons of water per day during the peak consumption period which traditionally is in the second half of July.

The present well field can produce about twice the daily demand. That quantity is thought to be adequate but the quality is of a concern.

Nitrate content, while still within the acceptable range, has been climbing.

Should the nitrate concentrate exceed the state limits, the city considered several options before deciding on the reverse osmosis plan. One of the plans would have abandoned the field east of town and relocated the wells to an area west of Bostwick. This was determined to be a costly alternative with no assurance the quality would meet the standards over the long term.

The selected reverse osmosis system will remove not only the nitrates but also dissolved solids, sodium and normally occurring organic and inorganic materials,. The result will be much softer water than is currently available. The present water supply has an average hardness of 26 grains.

It appears construction of a treatment plant will qualify the city for a $2 million grant from the state and perhaps another half million from the federal government. The remaining balance can be financed through a state fund with a 1 percent interest rate.

It is projected the treatment plant will cost about $73,000 per year to operate. Andrew Brittenham, city utilities superintendent, said the current water rate will cover the operation of the system.

The system is expected to operate at 95 percent efficiency, meaning only 5 percent of the water pumped will be lost in processing.

The current well field is the city’s fourth field. It replaced a field located on the river bottom south of the community. One of the early fields was located beneath a river bridge west of the city.