Berryville Council gets look at wastewater treatment options
Berryville -- Mayor Tim McKinney and members of the City Council were presented several options for the expansion and upgrading of the city's wastewater treatment plant Tuesday evening by engineers hired to conduct a study.
Engineers Chuck Nickle of USI Arkansas, Inc. and Steve Yonker of Burns & McDonnell Consulting Engineers made a PowerPoint presentation prior to the council meeting outlining the results of the study authorized last year by the council.
At issue is the need for reduction of the amount of phosphorus and nitrates discharged by the plant. Regulations are due to become more stringent by the first of next year, according to the engineers, and the federal Environmental Protection Agency (EPA) standards for treatment of biosolids are becoming more stringent.
While the studies showed the existing plant capable of handling the city's wastewater volume for several more years, options were presented which would reduce phosphorus and nitrates in the plant's discharge. The engineers presented three scenarios the city could pursue to meet the changed regulations.
The first would require the addition of an anaerobic basin to the existing plant to reduce the phosphorus in the sludge by 60 percent. Additional phosphorus removal could be achieved by adding alum to the sludge, which the engineers said could run from $180 to $250 per day of treatment. The city would still have to haul and land- apply the remaining liquid sludge in the same manner as they are now doing.
This proposal would require capital expenditures of about $41,000 and annual operating expenses of $165,000 per year for the hauling and land application.
The second proposal was for the addition of a belt filter press and dewatering system plus covered sludge storage. That would reduce the amount of water in the sludge and reduce its volume. The resultant sludge would be classified as Dewatered Class B biosludge, which would still be hauled, but probably to a landfill rather than land applied.
This proposal would require capital expenditures of approximately $2.5 million but annual operating expenses would drop to about $52,000. Amortizing this option over 20 years would result in an annual cost of $247,000 a year.
The third proposal, which appeared to intrigue the city officials, was to go one step further than the second option and add a sludge drying system. The resultant residue would be a Class A biosludge which could be land applied without special permits and could be used for lawns, golf courses, city parks or any other project requiring a safe fertilizer, said the engineers.The city could even bag the dried sludge and sell it. This process, they said, creates a minimal odor because the dryer exhaust has built-in scrubbers to remove any residual odors.
With the additional equipment required, this option's price tag would be a hefty $4.2 million with operating expenses, primarily for fuel for the dryer, of $109,000 per year. Using the same 20-year amortization, the annual cost to the city would be about $444,000.
On top of the three proposals, the engineers said a study of the existing plant showed another $500,000 to $600,000 worth of repairs, additions and upgrading are needed.
Nickles said following the design of the third option would require an increase in sewer rates of about 30 percent, which would raise a typical residential customer's bill from $8.50 to about $11. If both water and sewer rates were raised, he said the percent of increase would be less.
Following the timetable contained in the proposal, the refurbished and expanded plant could be in operation as early as the end of 2007, Nickles said.
Nickles said that after the city had completely reviewed the proposals, his firm would submit the chosen option to the Arkansas Department of Environmental Quality for approval.