It’s a hard-and-fast fact: The City of David City, Nebraska, has hard water. That translates to mineral buildup on faucets, sinks, and tubs; soap products that don’t work as effectively as they should; and dry, itchy skin for users.

To treat the situation, the City’s water treatment plant was operating as a lime softening facility to remove arsenic and soften the water to provide the best quality product possible to the community. Operating the 40-year-old plant required significant labor, and despite the staff’s best efforts, the facility was showing its age, with equipment frequently failing.

Recognizing it was time for a change, the City turned to us—and to closed-circuit reverse osmosis (CCRO).

What is Closed Circuit Reverse Osmosis?
Before diving into CCRO, it’s helpful to first understand conventional reverse osmosis. In this process, water is pushed through a membrane once via high pressure to remove contaminants such as nitrates, calcium, and other minerals. The purified water is collected while the remaining waste stream (brine) is discharged. Typically, about 75% of the input water is recovered as purified water—a measure referred to as the recovery rate.

CCRO, by contrast, is more energy-efficient, cost-effective, and less labor-intensive.  It’s particularly well suited for treating hard water. Unlike the conventional method that passes water through a membrane just once, CCRO recirculates the water in a closed loop. Water that still contains contaminants after the initial pass is repeatedly filtered through the loop, increasing the amount of purified water produced while minimizing brine discharge. As a result, the process can achieve significantly higher recovery rates.

The Selection Process
Prior to 2023, the David City water treatment plant operated as a lime softening facility to remove arsenic and treat the City’s hard water. This non-automated system was cumbersome, required extensive labor to operate, and produced a large amount of lime sludge residuals that were difficult to dispose of effectively. 

When the City set out to upgrade its infrastructure in 2020, it took a forward-thinking approach. It was open to exploring non-traditional solutions that could improve water-use efficiencies while also enhancing overall plant operations.

As the project began, we partnered with the City to evaluate several treatment options. Given the challenges of operating a traditional lime softening facility, we proposed the advanced CCRO system as an alternative approach to softening.

CCRO was unfamiliar to City leaders and staff members. Our team walked them through the system’s benefits, outlined expected outcomes, and identified operational requirements. We explained that the City would be able to reduce the labor requirements to operate the facility and see cost savings over traditional RO technology.

• CCRO consumes less energy than conventional RO, resulting in lower energy costs.
• Higher recovery rates generate less brine, resulting in lower disposal costs and reducing the amount of waste sent to the wastewater treatment plant.
• As an additional benefit, the system can be pre-set to run without continuous operator monitoring, eliminating the need for staff to spend several hours each day at the plant, freeing them up to work on other tasks.

Recognizing the system would be a substantial investment for the City, our funding team worked with the City to secure funding from the Nebraska State Revolving Fund Program. That resulted in $6.3 million in loan forgiveness. The project also received a low-interest loan for the remaining costs.

While formal decision-making rested with the City Council, they chose CCRO, realizing it provided the best long-term solution to meet their goals due to its ease of operation, elimination of lime handling by staff, improved water quality, and long-term sustainability. Their decision also reflected a clear commitment to public health and community well-being.

Implementation Begins
Once CCRO was selected, design began to take shape. The team worked closely with equipment vendors and system integrators to customize the CCRO application to fit David City’s unique water chemistry, flow demands, and space limitations.

During design—and into construction—a key constraint was accommodating the work within the plant’s limited physical footprint. The existing lime softening plant occupied the only available space for the upgrade.  To keep the facility operational throughout construction, the team developed a carefully phased approach. Partial shutdowns were coordinated, and a temporary chemical feed system was utilized to maintain continuous water service.

Construction spanned several years and progressed while the existing lime softening plant remained active. Once the new CCRO system was tested and brought online, the old lime system was demolished, and the area was repurposed to allow for a second CCRO unit. This second unit not only provides redundancy but can also be operated on high water-usage days. Flexibility was built in from the start, with space and electrical capacity reserved for a future third CCRO train.

In addition to installing the CCRO system, the project included upgrades to several plant components to support the new system. These included rehabilitation of aerators and gravity filters; construction of a new intermediate clearwell and pump building; cleaning and upgrades to the final clearwell; backwash tank improvements; chemical feed enhancements; a new security system; and building upgrades, including roof, paint, flooring, HVAC, lighting, and plumbing.

Our team recognized that operators would need strong support and training to run this state-of-the-art system. We delivered—and continue to deliver—hands-on training to guide their transition from a lime-based process to an advanced membrane treatment facility.

Because the community would be a primary beneficiary of the project, the City actively involved them in the plant’s upgrades. Public outreach efforts and facility tours highlighted the project’s impact, leading to the public feeling included in the process. This also fostered a sense of local pride and strengthened confidence in the City’s infrastructure. Once all upgrades were complete, a ribbon-cutting ceremony was held on plant grounds to celebrate the successful collaboration between engineers, City leadership, and the community.

The Results
This project challenges the assumption that high-efficiency membrane technology is only feasible for larger utilities. David City demonstrates that even with limited space, budget, and staffing, small systems can implement solutions that offer strong water-quality outcomes, long-term savings, and operational resilience.

With the system fully operational, the numbers speak for themselves.

• The CCRO process recovers 82–90% of water, compared to 75% in traditional RO systems.
• This results in saving an estimated 70,000 gallons per day (about 25 million gallons per year) and lowering discharge to the City’s wastewater facility and collection system.
• A new degassifier supports the CCRO and reduces chemical use for pH adjustment, paying for itself in under a year. This generates ongoing chemical savings of approximately $30,000 each year.

The system is fully automated and equipped with remote monitoring, allowing operators to monitor performance and make adjustments in real time. What once took three to four hours of on-site labor to operate the old lime softening system across multiple days per week now only requires minimal daily in-person checks, allowing operators to focus their time on other priorities while also enhancing operational consistency.

The new system also brings raw water contaminant levels below regulatory thresholds, protecting public health and improving taste, clarity, and color.

The completed CCRO system is a success—with both City leaders and the community. It meets regulatory requirements, extends the plant’s life by more than 20 years, improves water quality, and lays the foundation for future community growth.

David City Mayor, Jessica Miller, shared these thoughts. “These improvements are a testament to the City’s commitment to maintaining a strong, resilient water infrastructure. We’re invested in providing long-term solutions that keep our community safe and thriving.”

Looking Ahead
With a successful implementation under our belt, CCRO is another tool in our toolbox. As we partner with other communities—both inside and outside of Nebraska—we’re evaluating whether site conditions and community goals would make CCRO a good fit.

Your community may be a good CCRO candidate if it:

• Faces rising contaminant levels like nitrates or selenium in the raw water source;
• Utilizes raw water wells with very hard water;
• Has limitations on waste residual discharge to a wastewater plant or receiving water body;
• Wants to enhance a traditional filter water plant and improve water quality; or
• Faces challenges with new EPA regulations on novel contaminants like PFAS in source water.

If you’re interested in learning more, please reach out to me at ejoy@jeo.com. I look forward to helping your community improve its water.