The City of Boone, Iowa

The water plant uses a four step process to treat the water pumped from 14 wells along the Des Moines
River. After pumping from the wells, the water moves to the first three steps of the treatment process
which are aeration, lime softening and carbon stabilizing. The gravity filters are the final treatment step
for the water. The gravity filters remove any remaining pollutants in suspension in the water. Turbidity is
how this is measured. After a turbidity violation last summer at the water plant, it became apparent that
additional sand was needed for the gravity filters to work properly.

Originally the plant had 30 inches of special sand in the gravity filters but during the past 18 years of
constant use, nearly 8 inches has been lost, leaving only 22 inches remaining. This remaining 22 inches is
not enough to properly process the water during large summer water usage events, so there was some
lime residual in the water for a short period of time last summer that was quickly remedied by slowing
production.

Bid documents were prepared in October and bids were accepted for addition of special sand to the
gravity filters in November. HydroKlean from Des Moines was the winner at $39,250 for this work.
Work will begin in late January and will be completed by March. The work will occur along with normal
water plant operation, so there will be no disruption in service to the City. After completion of this work,
the plant will again be able to process large water amounts.

Proper maintenance and operation o f the water plant is a high priority and we will continue to monitor
the plant to ensure safe and continuous water service in the future.