NORWICH – A piece of the secondary treatment system at the City of Norwich Wastewater Treatment Plant has failed, and according to Department of Public Works Superintendent Carl Ivarson, more will fail in the coming months, making the need to move forward with the project at the plant even more crucial.
Representatives from Delaware Engineering, P.C. attended a meeting of the City of Norwich Water Commission on Wednesday night to explain the scope of the replacement plan. After examining several possible plans, the developers identified their recommended plan, which would probably raise sewer bills for city residents by approximately 15 percent a year for three years, which totals an average dollar amount of $10 per month or $30 a quarter.
“Media modules in all of the wastewater treatment plant’s Rotating Biological Contactors are deteriorating after over 20 years of service,” Dave Ohman, project engineer for Delaware Engineering, said. The wastewater treatment plant is made up of 18 RBCs on three separate trains. At any given time, two trains are in operation. The RBCs make up a large portion of the secondary wastewater treatment system, but due to their condition, they require extensive repair or maintenance to sustain adequate treatment.
Repairs are required to keep the city in compliance with New York State Department of Environmental Conservation requirements and upcoming limits for phosphorous and nitrogen levels that the Chesapeake Bay/Susquehanna River Basin Commission may require in the future.
The Chesapeake Bay requirements have not yet been issued, but the initial goal was to reduce nitrogen and phosphorous levels in the region.
Four different plans were examined. The first called for the replacement of the existing RBC equipment, and the replacement and addition of some other equipment that could help reduce nitrogen and phosphorous levels. The chemical feed facilities would also be modified for enhanced phosphorous removal. The total cost of the project is estimated at approximately $4.5 million.
The second two plans called for the introduction of a new treatment process, either a Moving Bed Biofilm Reactor (MBBR) or a Membrane BioReactor (MBR). Both plans would reduce nitrogen and phosphorous levels, however both plans are new and would require six months of pilot testing before the project could begin. Additionally, the plans would prove more expensive in the long run as operators trained on the systems would be hard to find and the level of operators needed to run the plant would be higher, which would raise operations and maintenance costs. The cost of the MBBR plan would total $5.3 million. The cost of the MBR plan totals $9.3 million.
The last plan called for the replacement of the existing RBC units with the Moving Bed Biofilm Reactor and the addition of denitrification filters. The project would cost over $17.6 million.
Ohman explained that from a monetary standpoint and from a time sensitive standpoint, the first plan seemed to be the best. The project could be completed in approximately 14 months. The other plans would require between 20 and 24 months.
Currently, the city has received a grant for $500,000 from the USDA Rural Development program. The city has also been approved for a $4 million loan through the same program. The city is currently looking at a 38-year term at an interest rate of 4.3 percent. However additional grants have been applied for, and if received, the loan could be paid off in a shorter period of time.
Water Commission member Ken Winans pointed out that the repairs are necessary. The project is not optional. Ivarson agreed, explaining that if nothing is done and the plant does not meet the DEC regulations, they could be fined $25,000 a day until the problem is fixed.
The repairs to the plant will be made in segments. One train will be repaired at a time, leaving the other two in operation. Ivarson said two trains would be able to adequately handle the waste while repairs are being made. Construction is expected to begin in January of 2009.