Project Overview

The City of Lincoln’s Wastewater Treatment Plant (LISWA), managed by Jacobs (Jacobs’ Operations Management and Facilities Services), provides critical wastewater treatment services for the rapidly growing Lincoln community. After years of operation, the facility began experiencing persistent mechanical issues with its existing competitor recirculation pumps. The operational issues included excessive vibration, seal failures, and clogging due to constant rag buildups.

As a result, the equipment required increased maintenance demands and caused operational disruptions with wastewater treatment plants process. Having previously installed Wilo TR-221 Submersible mixers throughout the oxidation ditches with reliable results, plant leadership once again turned to Wilo to provide a more dependable and efficient pumping solution for their Internal Recirculating Pump application.

The Challenge

The plant’s maintenance team struggled with frequent service interruptions and rising repair costs. The existing pumps experienced ragging issues almost at once after installation. Moreover, existing pump’s lip seal design proved prone to premature failures. These problems caused significant vibration to the pumps and reduced overall reliability.

Maintenance events, which needed extensive labor efforts by the onsite operations and maintenance technicians, further compounded the issue. Service work for the installed pumps averaged six to eight hours to complete, often consuming an entire workday. For context, the plant averaged 20 annual maintenance events and spent approximately $35,000 per year on repairs.

“The previous pumps quickly became one of the most labor-intensive pieces of equipment we had,” said Gary Hengst, Plant General Manager for LISWA. “We were dealing with ragging issues and repeated repairs that required significant downtime."

The Solution

To resolve these operational challenges, Wilo supplied four Wilo RZP recirculation pumps, engineered specifically for demanding wastewater applications.

The Wilo-RZP pumps feature precision-balanced hydraulics and robust construction designed to minimize vibration and improve long-term stability. Their mechanical seal configuration and self-cleaning impeller geometry help reduce rag buildup and clogging, improving reliability in solids-handling environments.

Operators also quickly noticed improvements in serviceability. The Wilo-RZP’s stainless steel construction and stable guide rail system simplified maintenance compared to the previously installed cast iron recirculation pumps allowing operators to remove and reinstall pumps more efficiently for inspection or cleaning.

“The Wilo units are much easier to work on,” said Joe Steer, Maintenance Supervisor at LISWA. “The rail system is more stable, and the stainless design makes maintenance simpler when we need to pull the pumps.”

Wilo’s team also supported the project with factory start-up and commissioning services. Wilo representatives worked directly with plant staff during installation and start-up to ensure smooth transition to the new equipment and provide optimal system performance.

Results & Customer Benefits

Since installing Wilo RZP pumps, the Lincoln Wastewater Treatment Plant has experienced significant improvements in reliability and maintenance efficiency.

Reduced Downtime
Maintenance events that previously needed a full workday can now be completed in 25–30 minutes, dramatically reducing service disruptions.

Lower Maintenance Costs
With fewer repairs and improved reliability, the facility has seen a substantial reduction in annual pump repair costs.

Improved Operational Reliability
The elimination of chronic vibration and clogging issues has improved overall plant performance and reduced the risk of unexpected shutdowns.

Simplified Maintenance
The stable guide rail system and stainless-steel construction make pump removal and servicing faster and easier for operators.

“The Wilo pumps have helped take the stress out of keeping the system running,” Hengst added. “They stay online and allow our team to focus on other critical plant operations”.

Why Wilo

LISWA selected Wilo based on its proven history at the facility and its reputation for reliable, high-performance equipment. The success of previously installed Wilo mixers, and the company’s responsive support, reinforced the decision to implement Wilo recirculation pumps as part of the plant’s equipment upgrades.

Plant operators also noted Wilo’s collaborative approach during installation and commissioning, working closely with both Jacobs and plant personnel to ensure the system was fully functional from day one.

Project Partners

• Client / End User: City of Lincoln, California (LISWA)
• Operator: Jacobs – Gary Hengst, Plant GM; Joe Steer, Maintenance Supervisor
• Contractor: City of Lincoln / Jacobs
• Wilo Team: Tom Webb – Western Regional Sales Manager, Frank Butler – Aftermarket Sales Manager

Key Products

• Wilo-RZP Recirculation Pumps (4 units)
• Wilo-TR 221 Mixers (8 existing units on site)
• Services Provided: Factory start-up & commissioning and potential for an ongoing service agreement.

Summary

The Lincoln Wastewater Treatment Plant upgrade proves how properly engineered equipment can significantly improve operational reliability in demanding wastewater environments. By replacing failure-prone recirculation pumps with Wilo RZP units, the City of Lincoln reduced maintenance demands, minimized downtime, and improved overall system performance.

Backed by Wilo’s engineering expertise and responsive field support, the facility now uses a more dependable and maintainable recirculation system designed for long-term performance.

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