Summary of the Plant and Its’ Performance

1)  Bar Screen

The Bar Screen is utilized for removal of heavy debris that could cause damage to pumps and clog pipes. This includes rags, sticks, rocks and large chunks of grease.

2) Grit Tank

The term grit is used for material that would cause wear on pumps and other equipment. Sand, gravel, eggshells and coffee grounds are all types of grit. When the flow of water is slowed down the heavier material will settle to the bottom and can be removed by the bucket elevator. The grit is then disposed of at a landfill.

3)  Influent Pump Controller

The influent pump controller allows the alternating of all three raw sewage pumps. Equalization of wear and adequate exercise of all pumps to maintain lubrication are the benefits as well as greater control over influent wet well levels.

4)  Primary Treatment

The primary tanks are used for the removal of heavy solids and grease. Heavy sludge settles to the bottom where the flights (scrapers) move it into hoppers. The sludge is drawn from the hoppers then pumped to the digesters. The grease is skimmed off the top and sent to the same tank.

Each primary tank holds about 42,000 gallons of water.

5)  Expanded Aeration Capacity

The aeration tanks were originally designed for BOD (Biological Oxygen Demand) removal only. Now we also use them for removal of ammonia as dictated by our NPDES permit (National pollution discharge elimination system). The permit changed in 1990 to include a parameter for ammonia and it was deemed necessary that three tanks would be needed for ammonia removal at our design flow of 1 MGD. Current flow necessitate the use of only 2 tanks, however all three are utilized for maximum efficiency.

6)  Secondary Treatment

The final tanks are used for removal of solids that would not readily settle in the primary tanks. This sludge is then returned to aeration to maintain a proper balance of solids for treatment.

7)   Return Activated Sludge (RAS) Controls and Division Chamber

The return sludge pumps are equipped with variable frequency drive (VFD) controls and motors, which are in turn controlled by a RAS well level controller. The sludge is pumped to a division chamber where it is returned to the aeration tanks. A small amount is constantly diverted (wasted) to the primary tanks to maintain a stable quantity of activated sludge in the aeration process. Wasted sludge is then dewatered and taken to a PPG land reclamation site.

8)  Tertiary Rapid Sand Filters

The traveling bridge filters were put online in March of 1992. They assist the plant in maintaining suspended solids in the effluent at less than the 12-mg/l limit set in our permit. In the 12 months prior to their installation the WWTP averaged 11-mg/l suspended solids discharged with two violations of the limit. An average of less than 3.5-mg/l has been maintained since the filters were brought online. This translates into about 22,000 lbs. of solids prevented from escaping the treatment plant every year!

9)  Chlorine Disinfection

The chlorine disinfection system includes the ability to chlorinate the effluent water prior to filtration as well as after filtration. This allows plant operators to control coliform bacteria, keeping them within NPDES permit limits.

10)  Digesters

The digesters are used for the breaking down of raw sludge. They utilize air for this purpose. After the “volatile content” (odor causing) of the sludge is reduced it is pumped up to the belt filter press. 

11)  Ashbrook Sludge Press

The one meter Ashbrook Belt Filter Press was added in 1995 to aid in sludge removal. Previous filter presses were only able to achieve a solids content of about 10%. The Ashbrook press averages 18-21%.  This translates into a large savings for the village because more sludge is removed by volume.

12)  High Flow Equalization Tank

Due to the aging sewer collection system, large volumes of storm runoff infiltrate the sanitary sewer system. At times these storm flows exceed the capacity of the Wastewater Treatment Plant. In the past, this excess flow was diverted through the old treatment plant into the river with settling being the only treatment. To eliminate this bypass of untreated sewage to the river a 697,000-gallon tank was constructed on the site of the old Solon Rd. Wastewater Treatment Plant. (Currently the service dept. garage) Since the EQ tank was put into service in April 1992 over 10,000,000 gallons of raw sewage have been prevented from entering the river.