Water Pollution Control

Organization & Service Area

Defiance Water Pollution Control (WPC) division is responsible for over 100 miles of sewer lines and 24 pump stations in addition to operating a 6.5 million gallon per day treatment plant.

The treatment plant is responsible for processing and treating sewage from The City of Defiance, portions of Defiance County, and The Village of Ayersville.

The division consists of 4 administrative staff members, 4 plant operators, 1 chief operator, 4 maintenance mechanics, 4 equipment operators, and 1 lab chemist.

Per Ohio EPA, WPC is required to administer a pretreatment program. Responsibilities include monitoring and controlling non-domestic industrial users to ensure that their wastewater discharges comply with federal, state, and local regulations and requirements. The pretreatment program’s primary goal is the protection of the sewer system, treatment plant, and the receiving stream from harmful or toxic discharges.

“Achieving environmental standards and providing quality and dependable service for our customers through teamwork.”

Wastewater Treatment Process

Facility Layout

Facility Layout

Raw Influent
Raw wastewater is collected throughout the City through a complex system of sewers and pump stations and conveyed to the treatment plant. The combined sewage then flows by gravity to the Grit and Screening Building.

Preliminary Treatment

Preliminary Treatment

The bar screen and grit tanks remove large debris and heavy grit prior to primary treatment.

Primary Treatment

Settled solids are removed in the primary settling tanks and pumped to the digesters. The primary settling tank effluent flows to the settled flow diversion chamber where it can be directed to the roughing towers or the aeration tanks.

Secondary Treatment

Flow from the primary treatment process is pumped to the two roughing towers for the removal of organics. Roughing tower effluent flows to the aeration tanks for further biological treatment.

Secondary Treatment and Final Settling

Ammonia nitrogen is biologically removed in the aeration tanks. Phosphorus is removed by chemical precipitation in the final clarifiers.


The treated wastewater is disinfected to ensure compliance with the City of Defiance National Pollutant Discharge Elimination System (NPDES) permit.

Final Effluent

After the effluent is disinfected it is then discharged to the Maumee River.

Solids Stabilization and Storage

Biosolids are pumped from the primary settling tanks to the anaerobic digesters for volatile solids reduction and stabilization. Digested biosolids are stored in lagoons where it is dewatered and thickened. On a seasonal basis, the thickened biosolids are then transported to area farmland. The biosolids are injected into the soil to act as a conditioner and fertilizer. Biosolids management, including storage, handling, and application, is conducted in accordance with both federal and state environmental regulations.

Wastewater Treatment Operation & Maintenance

Plant Operations
Plant treatment processes and equipment must be physically checked by plant operators and monitored to ensure that wastewater treatment standards are maintained and equipment is functioning at peak efficiency.

Monitoring and Control
Treatment plant processes are monitored and controlled by a computer-based instrumentation and control system. This system records wastewater flows entering and leaving the plant, the status of the 24 pump stations located throughout the city and also provides printed daily reports of plant and pump station operating data. Any abnormalities in equipment or processes, sends an alert to the computer allowing the conditions to be corrected promptly. After hour alerts are sent to supervisors cell phones.

The plant’s raw wastewater, process streams, and treated effluent must be constantly monitored by the laboratory chemist to ensure that the processes are operating efficiently. The lab chemist also monitors and tests industrial wastewater discharges for compliance.

Plant Maintenance
The maintenance mechanics are responsible for the care and maintenance of the wastewater plant facility and 24 pump stations.

Sewer System

Currently, the city’s sewer system consists of both combined and sanitary sewer lines ranging from 6-inches to 54-inches in diameter. Combined sewers are designed to carry both domestic sewage and rainwater. Sanitary sewer lines are designed to convey strictly domestic sewage and industrial discharges. The sewer system consists of over 100 miles of combined and sanitary sewers; more than 6 miles of sewer force mains ranging in size from 4-inches to 20-inches; over 2,600 manholes; 28 combined sewer overflows; and 4 river crossings.

On a daily basis Water Pollution Control employees provide emergency and preventive maintenance on the 100 miles of city combined and sanitary sewers. The sewer line maintenance is accomplished by utilizing the City’s combination high pressure sewer jet/vacuum truck and camera truck.

Pump Stations

The Defiance sewer system is designed to work primarily by gravity, which means it is designed so that wastewater flows downhill from the source to the treatment plant. Due to the relatively flat terrain in the Defiance area, it is necessary to pump the water at various locations in the city, using electric pumps, so that gravity can again take over and continue the flow toward the treatment plant.

The City has a network of pump stations positioned at key points throughout our sewer system. These pump stations are located both inside and outside of the City limits and were named for their geographic location in the City.

Pretreatment Program

The City of Defiance is required to comply with comprehensive Federal and State regulations governing how we control the sources of our wastewater.  The Pretreatment Program is administered by the City for all industries inside the City limits as well as outlying rural areas to the north and south of the city through the provisions of intergovernmental agreements.  Industries that meet certain standards as outlined in 40 CFR Part 403 and the City’s Sewer Use Ordinance Section 925 are required to obtain an Industrial Pretreatment Permit through the Water Pollution Control Plant.

The industries regulated by the Pretreatment Program must meet limits as outlined in their permit.  Sampling is performed by the City on the industries discharge to ensure compliance.  This applies to all new and existing businesses which discharge wastewater to the City sewer system.

For further information on the Pretreatment Program, please contact Water Pollution Control at 419-782-0841.

Contact Information:

Water Pollution Control
26273 State Route 281 East
Defiance, Ohio 43512


Office Hours:
Monday – Friday 8:00 a.m. – 4:00 p.m.

Superintendent – Mark Lehnert

Assistant Superintendent – Kevin Connor
Collection Supervisor –
Administrative Assistant – Angie Legg

sewer facts:

Combined sewers are sanitary wastewater and stormwater runoff that are collected in the same sewer. The combined flow is then transported to the Wastewater Treatment Plant.  Sometimes when it rains, combined sewers do not have enough capacity to carry all the flow to the Wastewater Treatment Plant.  In these situations, a portion of the untreated wastewater discharges into the Maumee or Auglaize River, creating a combined sewer overflow (CSO). These overflows help to minimize backups in homeowner basements during heavy rainfalls.

Long Term Control Plan:
The City is currently working with OEPA on a Long Term Control Plan (LTCP) to reduce the amount of CSO’s discharged during heavy rainfalls.  Over the last 10 years, the City has removed 16 CSO’s but still has 28 that remain active.  Although 28 remain, the City has done several projects to reduce the amount of overflows.

How to make a difference:
Remove downspouts from discharging into the sanitary sewer allowing storm water to “splash” on the ground.
Avoid using excess water during rain events. For example: avoid doing laundry.

Do not discard your grease into the drain. Scrape the grease into a can and dispose of it in the trash. Grease will build up in sewer lines restricting the flows.

Do not dispose of any wipes or feminine products in the toilet. These do not breakdown and can build up causing an obstruction.

For more information:
City of Defiance, WPC 419.782.0841

FOG stands for fats, oils, and grease and comes from: meats, lard, vegetable oils, shortening, butter or margarine, food scraps, baked goods, dairy products, and sauces. FOG is the leading cause of sanitary sewer overflows. A study in California found that about 78% of FOG-related sanitary sewer overflows were caused by residential areas. (Mitchell, Terry and Brook Parker. “Fats, Oil, and Grease Program CalFog Presentation, California Fats, Oils, and Grease workgroup, 26 January 2005.) What you do in your house really matters!

Why is FOG a problem:
When fats, oils, and grease get into the sewer system they stick to the inside of the pipes. Over time, FOG will build up in the pipe and create a blockage. Here are some possible results of a FOG clog:

•    Raw sewage overflowing into your home, yard, or street
•    Potential contact with disease-causing organisms, including E. Coli and Giardia ˡ
•    Expensive clean-up procedures
•    Increased sewer bills due to higher operation and maintenance costs to the sewer department
•    Damage to the environment, including algae blooms and fish kills.

How to make a difference:
•    For small amounts of grease, wipe out pots and pans with a paper towel after cooking and throw the paper towel in the garbage.
•    Scrape or pour grease and food scraps into a can or jar, then throw it in the garbage when it’s full.
•    Put a strainer into the sink drain to catch food scraps, and then throw the scraps in the garbage.
•    Never pour grease or food scraps down the sink or into the toilet.
•    Garbage disposals will not get rid of FOG. Disposals just move grease down the line and spread the problem!
•    Don’t rely on detergents that claim to dissolve grease. These products will also spread FOG through the sewer lines.

The best way to keep FOG from creating an overflow is to not let it get into the sewer in the first place!

For more information:
City of Defiance, WPC 419.782.0841


Recognize. Reduce. Recycle.

Mercury – also known as “quicksilver” since it is a silver-colored liquid at room temperature – is an element that does not break down in the environment. It occurs naturally and is found in oceans, rocks, and soils. Mercury becomes airborne as a gas or dust when rocks erode, volcanoes erupt, and soil decomposes; when people burn coal, oil, or natural gas as fuel; or when garbage containing mercury is incinerated.

Mercury in Defiance:
Mercury washed down the drain ends up at the City of Defiance Water Pollution Control Plant (WPC). Although most mercury is removed with solids at the plant, a small portion remains in the discharged wastewater. Our plant’s current discharge point is the Maumee River. Mercury discharged must be below a certain level set by the state. Removing even small amounts of mercury is expensive and may necessitate additional wastewater treatment facilities. However, with your help, the City may be able to reduce the amount of mercury in the Maumee River – without adding expensive treatment measures.

How can you help reduce mercury impacts:
1) Reduce the amount of mercury-containing products in your home. Recycling products is a great way to keep Mercury from entering the wastewater system.

Household Items That May Contain Mercury:

Ballasts (inflorescent lights), old alkaline batteries, appliance switches, mercurochrome, chest freezers, maze toys, gas pilot lights, contact lens solution, washing machines, light up sneakers, thermometers, household cleaners, thermostats, barometers, florescent lights, and/or chemistry sets.

2) When a mercury spill occurs, be sure to:

  • Increase ventilation in the room with outside air and close the room off from the rest of the house. Use fans for at least one hour to help ventilate.
  • When cleaning a mercury spill:
    DO NOT use a broom or paint brush
    DO NOT use a vacuum
    DO NOT use any cleaning products
  • Pick up the mercury with an eyedropper or scoop up beads with a piece of heavy paper.
  • Place the mercury, contaminated instrument and any broken glass in a plastic zipper bag. Place this zipper bag in a second, then third zipper bag (triple bag). Place bags in a sealed container.
  • Dispose of mercury in compliance with the state and local requirements.
  • If weather permits, leave windows open for approximately two days to assure the area is completely ventilated.

For more information:

Consumer Products Safety Information  800.638.2772

Poison Control  800.222.1222

City of Defiance, WPC 419.782.0841