By Tina Snell, Staff Writer
Planning for the growth of the city, the Motley Council heard from a representative from Bolton Menk Inc., Consulting Engineers and Surveyers. John Graupman spoke about constructing a new water treatment facility to replace the 20-year-old one now in use.
After viewing the city’s current plant, Graupman said the steel gravity filter, constructed in 1992, is currently operating above its capacity and that the electrical controls are obsolete.
The storage tower, said Graupman, was also constructed in 1992, and was in generally good condition. But, its coatings are near the end of their useful life and that it doesn’t supply adequate fire flow storage.
Based on 1 percent annual growth, the Council was told that in 20 years, Motley’s population would be more than 800 people, up 147 from the 2010 count.
With those numbers, Graupman said water demand would exceed well and filter capacity.
Suggested alternatives were to rehabilitate the existing facility and add a second filter or install new pressure filters, steel gravity filters or concrete gravity filters. Adding a reverse osmosis alternative to any of the filters was another option.
To rehabilitate the existing water treatment plant, Graupman said the city would need to rebuild the interior, add new coatings and a new filter. It would also have to erect a new building and he said this would not be economically feasible.
Pressure filters use multiple tanks for easy expansion, but have no aerator so there is a higher chemical use. They are also less efficient for manganese filtering.
A steel gravity filter has effective aeration and lower chemical use, offering a more flexible treatment.
Concrete gravity filters offer the most efficient aeration, said Graupman. They also have the lowest life-cycle costs.
Adding reverse osmosis treatments to any of the options would remove 99 percent of all effluents, provide chloride and sodium-free soft water and blend the water with filtered water to reduce corrosion and add taste.
The cost for a facility using pressure filters is $4.03 million, for steel gravity filters is $4.1 million and for concrete gravity filters is $5.07 million. If the reverse osmosis alternatives are added to each, $375,000 would be added to the cost.
Graupman said the cost to operate and maintain the facility would be about $40,000 less than the city’s existing costs. If reverse osmosis were to be added, another $120,000 would be added to the annual cost for chemicals, membranes and electricity, $80,000 more than the cost to run the current plant.
Adding in the payments for the facility, the cost to the city could be as much as $744,000 annually, based on a 20-year term at 2 percent interest.
Clerk Treasurer Terri Smith showed the Council the city’s financial report and due to the three years of infrastructure improvements and an updated wastewater treatment plant, the city has more than $5.3 million in outstanding indebtedness.
The issue of replacing the water treatment facility will be discussed at a future meeting.