By By ANDY HAMILTON / Niles Daily Star
NILES - Talks continued Monday night concerning the conditions of Niles Waste Water Treatment Plant.
Jack Rafter of the Grand Rapids-based architectural firm Fishbeck, Thompson, Carr and Huber, Inc. presented the Niles City Council and the trustees on boards of surrounding townships with a presentation on the condition of the plant.
Rafter said the recommendation from the firm to develop a master plan for the facility is in response to a Michigan Department of Environmental Quality (MDEQ) inspection performed at the plant in 2004.
The inspection identified five major areas Rafter said need attention; influent headworks screens, raw sewage pumps and piping, biosolids handling equipment, ferrous chloride storage and disinfection facilities.
The influent headworks screens have been in service for more than 25 years, are corroded and, therefore, are no longer capable of handling all the flows through the plant, Rafter said. The equipment continually requires maintenance and Rafter said the reliability of the screens are a concern.
The raw sewage pumps and piping at the plant are also more than 25 years old. Rafter said the equipment handles 14 million gallons of flow a day coming into the plant. Both the pumps and the piping leading to the pumps are eroding from the “grit” that flows in, Rafter said.
In his assessment of the biosolids handling equipment, Rafter said the current process used at the Niles plant is outdated and expensive. Zimpro was a popular process in the 1970s as a way to reduce the byproducts of waste water treatment, Rafter said. The process uses a combination of heat and pressure and is expensive because it requires a lot of natural gas, Rafter said.
The ferrous chloride storage containers have been weakened by exposure to ultraviolet rays over the last 25 years, Rafter said. There are occasional leaks in the pipes connected to the containers that have a corrosive effect on the equipment, he added.
Rafter said a structural analysis of the tanks was not completed.
Mayor Michael McCauslin suggested coating the tanks with a layer of sun protectant instead of replacing the equipment. If new containers are needed, councilmember William Weimer said an awning to protect the new tanks should be considered.
Rafter termed the plant's disinfection facilities, or chlorination equipment, as another “area of concern”. Again, Rafter said the age of the facilities has weakened their performance and limited their ability to feed enough chlorine gas at an efficient enough pace.
The recommendation from the firm is to switch the process from gas to liquid chlorine, Rafter said. The process is much safer and the new equipment can hold up to 5,000 gallons of the liquid, Rafter added.
The city is also under pressure from the MDEQ to eliminate its amount of combined sewer overflows (CSOs) into the St. Joseph River.
Both sanitary waste and storm water are carried in the city's combined sewers and are released into the river to avoid back-up flow into residential homes, businesses and streets.
The MDEQ has changed the requirement in National Pollution Discharge Elimination System (NPDES) permits, Rafter said. Niles' current permit through October 1, 2007 was given because the treatment plant was able to handle the maximum amount of rain expected to fall over the period of one hour based on the average rainfall over the last 10 years.
In order to obtain the new permit in April of 2007, Rafter said the Niles plant would have to be able to support the maximum rainfall in a 24-hour period based on the average of the last 25 years.
According to the capital improvement plan in Rafter's presentation, the total cost for all the necessary equipment to keep the plant reliable as recommended by Fishbeck, Thompson, Carr and Huber, Inc. is more than $19 million over five years.
Included in the city's options to cover the cost is a recent state initiative that offers a grant to help pay for engineering costs, Rafter said. The legislation allows the state to cover 90 percent of engineering costs up to $1 million dollars, Rafter said.
Niles is not the only municipality in this position, but, Rafter said those cities that have failed to act quickly on the problems have seen a quick increase in sewage rates because of the condition of their plants.
City Administrator Terry Eull said Niles remains in the evaluation and preparation process.
Eull added Niles is currently performing a cost analysis to examine the different scenarios available to the city.