The original Clinton wastewater Treatment Plant was constructed in the 1940's. The plant provided primary treatment consisting of grit removal, primary settling tanks, chlorination, sludge digestion and dewatering of sludge. In the original plant sand and other heavy inorganic solids were removed from the wastewater in the grit chamber. The effluent from the grit chamber entered the primary clarifier where suspended solids settled. The settled water was then chlorinated and discharged to the Raisin River. Settled solids from the clarifiers were digested, then dewatered on sludge drying beds prior to disposal.
The Village of Clinton Wastewater Treatment Plant was reconstructed in 1978-80 to increase capacity and improve performance. The new wastewater treatment facility was designed to remove 96 percent of biochemical oxygen demand, 95 percent of suspended solids, 80 percent of phosphorus and virtual elimination of disease producing organisms. These removal efficiencies are equal to or higher than stringent pollution control standards set by State and Federal government requirements. The high degree of treatment accomplished at the Clinton Treatment Plant is helping to improve the water quality of the Raisin River.
The new primary treatment facilities included an aerated grit chamber, macerator, and two primary clarifiers. The grit chamber recovers heavy sand and other inorganic solids, which may damage other process units. The macerator reduces the size of solids to a size that will safely pass through plant equipment. Finally, the primary clarifiers remove suspended solids from the wastewater.
The new secondary phase of treatment consists of rotating biological discs and secondary clarifiers. In contrast with the primary phase of treatment, which is physical in nature, the secondary phase is a combination of biological and physiochemical processes. The rotating biological discs are a series of honeycomb discs mounted inside a covered tank. Wastewater flows through the tank so only the lower portions of the discs are submerged. As the discs rotate, sections of the disc are alternately exposed to wastewater and air, and the discs become covered with a bacterialogical film. The bacterial population oxidizes various forms of organic matter from the wastewater as it grows. If the film becomes too heavy it may sluff-off the discs and settle in the secondary clarifiers.
Phosphorus removal is accomplished by the addition of chemicals to the effluent of the rotating biological discs. The resultant precipitate is also settled out in the secondary clarifiers. If additional phosphorus removal is required chemicals may be added prior to the primary clarifiers.
Tertiary treatment, in the form of sand filters, was also added to the treatment scheme during the reconstruction. Filtration of the secondary clarifier effluent has a polishing effect, which means that additional removals of suspended solids, biochemical oxygen demand, and phosphorus are achieved. The higher removal efficiency increases the quality of the water. The effluent from the sand filter is also chlorinated for disinfection prior to discharge into the Raisin River.
The 1978-80 reconstruction provided new solids handling facilities. A new digester, sludge holding tank and sludge drying beds were built. Solids removed from the wastewater are decomposed by a bacteria population which live in the digester. The bacteria stabilize the sludge anti in the process release methane gas. The stabilized sludge is then used by local farmers as a soil conditioner.
In 1992 the Village engineers prepared a Wastewater Treatment Plant Master Plan for Improvements, and a Supplemental Report on the Wastewater Treatment Plant. The Master Plan shows the historical and projected plant flows, explains each phase of the treatment process, provides a general evaluation of the plant, and makes recommendations.
The projected flows for 1995 to 2003 are high because of the significant decrease in consumption by one local industry. The sewer plant averaged 300,000 gpd in 1996. The plant was constructed with older technology and is based on highly mechanized systems. On page 8 of the report, in the two paragraphs above the Summary of Results and recommendations, it is clear to see that there are much cheaper systems to operate. The Village’s system was shown to cost $1,587 per 1,000,000 gallons and an oxidation ditch only $455.
"The purpose of the supplemental report was to determine if the Village could reduce the costs of operating their waste water treatment facilities by abandoning portions of the existing treatment plant and building an oxidation ditch." The report concluded that it would not be practically or financially advantageous. The current system was not at capacity, and the debt costs on the new system would offset its operating savings.
The current wastewater treatment plant was designed to handle 450,000 gpd with a peak flow of 1,250,000 gpd. That type of plant does not operate efficiently at peak design flow. Staff believes the plant would peak at only 400,000 gpd. Therefore, based on an average flow of 300,000 gpd, there are 100,000 gpd of capacity remaining.
The Village’s sewer rate is $6.00 per month for service charge and $6.75 per thousand gallons for residents within the Village, and $8.90 per 1,000 gallons of water metered for service outside the Village.
Connection fees for all residential developments, including single-family, two-family, multiple family, condominiums, apartments, mobile home parks, and any other type of residential use, will be charged based on the meter size required by each individual unit multiplied by the number of units. All connection fees for commercial and industrial type uses will be based on the meter size. Connection fees for water meters larger than 4 inch will be determined on a case-by case basis. All increases in meter size will be billed the difference in cost from the current size to the new size.
Meter Size Sewer
3/4 inch $ 3,400
1 inch $ 5,650
1 1/2 inch $11,325
2 inch $18,120
3 inch $36,280
4 inch $56,680
