Wastewater Operations

  1. Danbury Township Wastewater Treatment Plant
  2. Portage-Catawba Island Wastewater Treatment Plant

Danbury Township Wastewater Treatment Plant Overview

The wastewater entering the Danbury Wastewater Treatment Plant is treated in an aerated facultative lagoon system. Within the lagoons two types of microorganisms, aerobic and anaerobic, use the pollutants in the wastewater as food. The aerobic microorganisms live in the upper water level of the lagoon. They are maintained by a variable supply of air injected into the lagoons. These organisms will use pollutants suspended in the lagoon water as food.

Anaerobic microorganisms exist in the sludge layer in the bottom of the lagoons. Anaerobic microorganisms live in the absence of air utilizing the sludge layer as food. The sludge layer consists of settled pollutants of the wastewater, byproducts of the aerobic microorganisms, and dead organisms and algae. Together the aerobic and anaerobic microorganisms reduce the pollutants in the wastewater and sludge in the lagoon bottoms.

Danbury Township Wastewater Treatment Plant Components

Pre-treatment Building

Receives pumped wastewater from both sides of the peninsula and directs the wastewater through a fine screen and into an aerated grit tank to remove grit and debris. From there the water is directed to any of the three lagoons or combination of the three. Normal operation is to direct all flow to Lagoon Number 1 for series operations.


The three lagoons in the system each have a volume of 24 million gallons and a water depth of 17 feet. They are constructed on one of the few areas on the peninsula having a deep clay stratum. The clay forms an effective seal for the lagoon contents.

Aeration Equipment

Efficiently distributes air throughout the lagoons to meet the oxygen requirements of the aerobic microorganisms. The equipment is a membrane diffuser system manufactured by Environmental Dynamics Inc.

Air Blowers

Four positive displacement air blowers are located in the Blower Building on top of the dikes. The blowers compress air forcing it through the aeration equipment into the lagoons where it will provide oxygen for the aerobic microorganisms.

Tertiary Treatment

Actiflo system manufactured by Kruger further enhances the treatment process by using a polymer and alum for the removal of phosphorus

Chlorination System

Adds chlorine to the treated water after it has passed through the treatment plant to kill any disease-causing microorganisms remaining in the treated water.

Dechlorination System

Injects bi-sulfite into the water following chlorination to remove any remaining chlorine before discharge into the Sandusky Bay.

Sludge storage lagoon

Provides a means to store sludge from the Actiflo process which is later land applied in accordance with all EPA regulations.

Service Building

Contains an administration office, wastewater laboratory, chlorination room, repair shop, and storage areas.

Additional Plant Information

The plant has the capacity to treat an average sewage flow of 3.8 million gallons per day with a strength of typical domestic sewage. The plant is capable of providing the treatment required by the Ohio Environmental Protection Agency even when one of the lagoons is out of service.

The pipes handling the flow through the plant are so arranged that all raw sewage pumped to the plant must pass through the lagoons. It is not possible to pump sewage to the plant and then directly to the Bay. All flow must pass through the lagoons to reach the plant outfall which discharges to Sandusky Bay.

The aerated facultative lagoon system was chosen over more conventional treatment systems because the construction cost and operating cost are approximately one-half those of a conventional system.