Sewer

Wastewater Treatment

• We have a design capacity of 10.4 MGD with a maximum capacity of 32.7 MGD.
• On average, 5,912,000 gallons of water are treated each day.
• We begin by screening, which removes objects such as rags, stones, and other items that could damage equipment and clog the processes. Screened objects are washed and then disposed of in a landfill.
• Grit separators remove small gravel and sand particles that could cause damage to equipment over time. Collected grit is washed and disposed of in a landfill.
• Primary clarifiers create a zone of slowly moving flow to allow floatable solids to be skimmed off and the heavier solids to settle. The settable solids collect at the bottom of the tank and create sludge that is pumped to the digesters.
• Aeration tanks are injected with oxygen to allow microorganisms to feed on the high concentrations of inflowing organic matter.
• Secondary clarifiers allow floatable solids to be skimmed off and the microorganisms to settle to the bottom where a portion is pumped to the aerobic digesters. Some of the solids are recirculated back to the aeration tanks.
• Chlorine is added to a contact tank to disinfect the flow from the secondary clarifiers.
• Sodium bisulfite is added at the outlet end of the contact tank to remove any chlorine remaining after disinfection.
• Effluent flow is discharged into the Ohio River.

Biosolids Treatment

• Aerobic digesters are aerated tanks where microorganisms break down the organic matter in sludge, producing “biosolids.”
• Anaerobic digesters are tanks that heat and mix the sludge in a zone that is free of dissolved oxygen where bacteria decompose waste matter into biosolids.
• Dewatering is where polymer is mixed with the sludge and then pressed by a belt and roller system to remove excess water and dry the biosolids into a cake-like substance.
• The dewatered biosolids are beneficially reused as a soil conditioner for area farms in compliance with a PUB Biosolids Management Program as well as state and federal guidelines. The biosolids are spread on farm fields not used for crop production.

Collection

• Our gravity collection mains stretch across 210 miles.
• We have 7.2 miles of force mains.
• Our collection system contains 17 pumping stations
• Collection system maintenance is a high priority with dedicated resources including:
  
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Pretreatment, Hauled Waste, and Fats, Oils, and Grease (FOG) Programs

PUB operates a pretreatment program for industrial sewer dischargers to monitor and help regulate the strength and quantity of hazardous and harmful materials flushed to the wastewater collection system. The hauled waste program provides the same protection for septic tank haulers as well. The FOG program works with dischargers to protect lines from buildup of grease deposits that decrease the capacity of the collection system and cause other problems for the operation of the collection system. PUB issues permits for these services and monitors the permit holders to help ensure compliance with the programs.