Emergency After Hours Phone: (989)-224-9192

The City of Saint Johns owns and operates the Publicly-Owned Treatment Works (POTW), known as the Wastewater Treatment Plant (WWTP) and is responsible for treating all residential and commercial sanitary sewage generated in the City Limits as well as portions of Bingham Township.

Sewage is transported through the collection system, which is made up of over 45 miles of pipe and includes multiple lift stations. Lift station pumps raise the liquid to a level from which it can flow by gravity to the plant.

The WWTP is designed to effectively treat an average daily flow of 1.9 million gallons per day (1.9 MGD). Although the Plant can handle this “hydraulic” water load, including temporarily-higher flow spikes, continuous treatment is practical with typical daily flows of 1.4 to 1.5 MGD.

What is Wastewater?

Wastewater or sewage is the byproduct of many uses of water. There are the household uses such as showering, dishwashing, laundry and, of course, flushing the toilet. Additionally, companies use water for many purposes including processes, products and cleaning/rinsing parts. After the water has been used, it enters the wastewater stream and flows to the wastewater facility for proper treatment.


A utility/street permit must be completed prior to performing any work in the City right-of-way. Fees may apply depending on work. Contact City Offices at (989) 224-8944 for further information.

Plant Process are as follows:

Phase I - Influent Treatment


To remove in-organics (grit) and large solids through screening devices. Metering and equalization of the influent flow combined with the introduction of ferrous chloride (FeCL2) and air.


Incoming or influent flows are introduced to the first stage of treatment, utilizing four large pumps. This is an automated process operated by a bubbler system.

Phase II - Primary Treatment


To remove sludge and reduce phosphorus as well as suspended solids levels.


In this stage, a polymer is introduced at the inlet of the primary tanks. Polymer combined with the ferrous chloride creates a ion exchange (positive/negative), which coagulates the solids, ultimately settling to the bottom of the tank. These solids are then pumped through a heat exchanger/boiler unit and into the digesters.

Phase III - Secondary Treatment


To remove biological oxygen demand (BOD), Ammonia Nitrogen and polish the small pin flock solids that is collected in the secondary clarifiers.


Using Rotating Biological Contactors (RBC), natural organisms that are present in domestic waste are used to remove both ammonia nitrogen as well as BOD. The first three stages in each train remove the BOD, while the remaining two stages are used for nitrogen removal. Any remaining solids are settled out in secondary clarifiers and are returned to the front of the plant.

Phase IV - Tertiary Treatment


By using sand filters, any remaining impurities left in the water leaving the facility is filtered out.


After secondary treatment, the water is introduced to the mixed media filters, which consists of sand, stone, and charcoal. The water is then disinfected with chlorine and de-chlorinated with sulfur dioxide and discharged to the St. Johns Big Ditch.

The Wastewater Department staff are responsible for repairs and maintenance to the equipment at the Plant, as well as the Lift Stations. Plant staff also monitor and perform laboratory analysis on the sewage as it undergoes treatment at the Wastewater Plant. The treated sewage must meet stringent State and Federal Standards before it can be discharged to the St. Johns Big Ditch.

All plant operators are required to hold a minimum of a Class D Wastewater Treatment license as issued by EAGLE. Combined, the Wastewater staff has exceeded State standards by obtaining Class B, and class C, Wastewater Treatment licenses. Operators attend many training courses throughout the year to stay updated on the industry and to increase job knowledge.

What is Inflow & Infiltration (I & I)?

Inflow is water from a sump pump or roof drain. This relatively clean water should be connected and discharged to a storm water system. In some cases, homeowners connect sump pumps (illegally) to the sanitary sewer because it is relatively easy and inexpensive.

Infiltration is groundwater that seeps directly into sanitary transmission systems, usually during the spring heavy rains and melting snow.

The City of St. Johns Wastewater Treatment Facility receives an average daily flow of 1.3 million gallons of wastewater from residents and businesses within the City and portions of Bingham Township. Our facility provides tertiary treatment utilizing biodisks and filtration technology.

We initiated many improvements with a construction project that began in July 2008 at the St. Johns facility. We implemented a very practical design to limit the cost for our community. At the same time, replacing old equipment, rerouting portions of the flow to gain wet-weather capacity further increased efficiencies throughout the processes.

We welcome the opportunity to explain the operation and regulations/requirements we must achieve at your public-owned wastewater treatment facility.

Store It... Don't Pour It!
Please Help Save our Sewers from the Beast of Grease!

A common cause of sewer backups in St.Johns is pipes blocked by grease. Sewer backups and overflows can damage home interiors, cause health hazards, and threaten the environment. No one wants to experience a backup but everyone can help. For household cooking greases and oils remember: Store it... Don't Pour it!

Non-Domestic User Survey

Service Request

We provide residential assistance in the event of a sewer back-up. During normal business hours (7:00 a.m. - 4:00 p.m.) residents can call (989) 224-8944, Ext 230. After hours, calls can be placed to the Emergency Answering Service at (989) 224-9192. City personnel will quickly respond to any/all calls and verify problems.