Wisconsin's fourth largest plant undergoes a major upgrade in its wastewater treatment

The Racine Wastewater Treatment Plant, located on the shore of Lake Michigan in Racine County, Wisconsin, provides wastewater treatment for eight satellite communities.

The design capacity is 36 million gallons per day (mgd), and the plant capacity is 108 mgd. There are two flow balancing pools, each with a capacity of 100 million gallons. In theory, it can treat 308 million gallons of water, but it is usually between 150 and 180 mgd when it rains heavily.

The factory’s system was outdated, and there was a lot of inflow and infiltration during the rain event; in fact, it surprised new operators.

"When we have had a lot of rain, it may be more typically 150 to 180 mgd, which is a lot of water!" said Mary-Frances Klimek, director of Racine's wastewater utilities. "When we have new operators coming in, they see that all this is done through this transfer structure, and you usually see the shock on their faces. I won't say this is panic, they know what to do , But they have never seen such a serious number before."

Due to flow challenges, especially during rainfall events, construction and upgrades are usually centered on flow management. However, the staff of the facility is ready to deal with anything. From unforeseen events and unexpected rainfall to simple adjustments, operator flexibility is something to be proud of.

"I am most proud of the people who work with me. We have a group of people who take what they do very seriously," said Mary-Frances Klimek, Racine Wastewater Utility Supervisor. "Our daily goal is to discharge the best sewage from our factory to Lake Michigan, as well as the emissions into the air. Our employees have solved the problem of many factories hiring contractors to deal with."

The Racine Wastewater Utility Company discharges sewage to Lake Michigan. Two lines enter the factory, one from the north and one from the south. Adding ferric chloride at the front of the factory to limit phosphorus can help reduce H2S.

The water flow enters the diversion structure and passes through the preliminary and pre-treatment building. The plant has two vortex sand removal devices, each 70 mgd, used to continuously remove coarse abrasive inorganic materials from the screened water stream.

The preliminary treatment building contains four strip-shaped screens, each with a rated maximum capacity of 35 mgd. The sludge passes through each of them and then through one of the 12 primary clarification tanks. The clarification tank is divided into east and west sides. The plants alternate between these throughout the day. This is because the nutrient removal of the 12 clarifiers is too large, and they do not have enough biochemical oxygen demand on the back of the plant.

From the primary clarifier, the sludge is pumped from the bottom of the tank into one of the four digesters, and then the solids in these digesters have a residence time of about 4 to 5 days. From there, the sludge enters a storage tank, which used to be a secondary digester. The sludge is then pulled from the storage tank to six belt filter presses.

The sludge enters one of the two trucks from the belt press, and then drags the cake to the warehouse or farm.

When the water leaves the primary clarifier, the primary sewage flows through a channel to the back of the plant, where it enters the aeration system. There are five aeration tanks, the volume of each aeration tank is about 1 mgd, and the aeration capacity is about 5 mgd. From there, the water stream enters one of the nine final clarifiers and then into one of two ultraviolet (UV) disinfection systems. From here, the water is discharged to Lake Michigan.

The Racine Wastewater Treatment Plant is in the final stage of completion of its 20-year facility plan. This stage involves an aeration project, replacing the fine bubble diffuser with a membrane diffuser. The plan also includes a new UV system, new engine, blower, engine generator and biogas cleaning system. The team also plans to add dishwasher lids. Recently, the team completed the restoration of the digester cover and added a walkway between the two primary clarification tanks. As the fourth largest factory in Wisconsin, the factory and collection system teams can cross.

Klimek added that most of the plant's equipment and operations are redundant. The team has also developed a comprehensive training plan for the operation, maintenance and safety of all equipment and processes in the factory and collection system.

Cristina Tuser is the associate editor of WWD. Tuser can be reached via [Email Protection]

The Water and Waste Digest staff invites industry professionals to nominate what they consider to be the most outstanding and innovative water and wastewater projects to be recognized in the annual reference guide question. All projects must be in the design or construction stage within the past 18 months.

7 basic types of temperature measurement sensors

Flint water crisis: 7 years later

What is biological oxygen demand (BOD)?

What is sewage treatment aeration?

What is total suspended solids (TSS)? 

©2021 Scranton Gillette Communications. Copyright Site Map| Privacy Policy| Terms and Conditions