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Treatment Facilities

Water Treatment Plant

April 8, 2024

The original Great Bend Water Treatment Plant was constructed in 1983 and the equipment had outperformed its useful life. Red Rock Rural Water System (Red Rock) faced a dilemma: rehab a nearly 40-year-old facility to extend its useful life, or start fresh by constructing a new facility. Red Rock worked with DGR Engineering to begin design of a new state-of-the-art water treatment plant that would provide continued growth opportunity for Red Rock’s next 40 years of operation.

Two new production wells were drilled and developed a total of 1,100 gpm of new capacity. Red Rock also wanted to incorporate operational improvements over the old treatment plant, including a dedicated office space with a fully functional master SCADA computer that can operate all components of the plant, as well as all other facilities in the water system. Pneumatically actuated valves on the filters are tied into the SCADA controls to automate the backwash process.

Two rapid infiltration basins were constructed to collect backwash water from the filters. The infiltration basins allow the backwash water to recycle back into the aquifer while filtered particles settle out on the surface of the basin.

The new Great Bend Water Treatment Plant went into full-time operation in May 2023. By the time the new facility went on-line, the original Great Bend treatment plant was functioning at only 60% of its designed capacity. Initially the new facility will operate at 1.2 million gallons per day (MGD) at a flow rate of 1,000 gpm.

The building is expandable to add future treatment equipment that can double the treatment capacity as water demands increase in the future. With three times more water available and enough annual water appropriation to operate at full capacity all year long, the new facility has become Red Rock’s primary water source.

New Water Treatment Plant

October 24, 2022

New Water Treatment Plant

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Vision Becomes Reality

Iowa Lakes Regional Water's Osgood Water Treatment Plant

Project Owner:
Iowa Lakes Regional Water

Key Experience:

  • RD Water and Waste Disposal Loan and Grant Program Funding
  • Piloted technology to prove concept

Key Features:

  • Direct treatment reverse osmosis water treatment plant
  • 750,000 gpd capacity, expandable to 2.25 MGD
  • Utilizes shallow alluvial wells located approximately 2.5 miles away from the plant
  • Membraned system provides a modular style construction that allows for easy expansion

Iowa Lakes Regional Water (ILRW) provides water service to small communities and nearly 5,000 rural residents in northwest Iowa. The ILRW system encompasses over 200 square miles of service area in all or parts of Dickinson, Emmet, Clay, Palo Alto, Buena Vista, Sac and Cherokee Counties in Iowa and Jackson County in Minnesota. Water demands within the ILRW system are diverse, from high residential and tourism demands in the Lake Okoboji and Big Spirit Lake areas in the northern part of the system, to rural residential and large agricultural demands in the remainder of the system.

The Lakes area of the ILRW system has experienced significant growth as it has become a popular tourism location for residents of the upper Midwest. As ILRW developed the Lakes Area, they initially purchased water from a municipal system that treated surface water from Lake Okoboji. This source was an economical option to get the new distribution system started, but recent changes in surface water treatment has led to rising treatment costs and challenges with increasing disinfection byproduct concentrations. ILRW had the goal to provide this area and other rural customers with a higher quality and more economical water source than what they received from their bulk sources. A new treatment plant, the "Osgood" water treatment plant, fulfilled that goal.

The development of the Osgood water source has been a goal of ILRW for decades. As ILRW developed the eastern side of its system, ILRW and DGR Engineering (DGR) worked together to design and install transmission capacity capable of incorporating the Osgood water source, knowing that the new WTP would be needed in the future. The three goals of the project were as follows: to gain independence from purchased water sources, to provide high quality water to existing customers, and to accommodate system growth.

The plant is located along the Des Moines River between Graettinger and Emmetsburg, Iowa. The well field is in a shallow alluvial aquifer approximately 40 feet deep located 2.5 miles east of the water treatment plant and on the eastern side of the Des Moines River. The water treatment plant is located on the western side of the river at a much higher elevation and out of the flood plain of the river. Osgood has a capacity of 750,000 gallons per day and is easily expandable to 2.25 MGD.

The project was developed using the United States Department of Agriculture Rural Development’s (RD) Water and Waste Disposal Loan and Grant Program, which has been the primary funding source for many ILRW projects. ILRW was able to obtain a loan and grant package from RD that enabled the project to be affordable to existing ILRW customers without having to raise rates.

All of ILRW's existing sources provided softened water, so it was prudent that any process considered incorporate softening. Hardness removal can be achieved through precipitation within conventional processes (lime softening), ion exchange, or non-conventional processes such as electrodialysis and membranes.

During the preliminary engineering report phase, ILRW and DGR evaluated three alternatives to achieve the treated water quality goals:
• Lime softening
• Nanofiltration/reverse osmosis (RO) with pretreatment
• Nanofiltration/reverse osmosis direct treatment

Many alternatives were considered but a direct treatment reverse osmosis water treatment plant was selected due to the lowest initial capital investment and ease of operation. The membraned system also provides a modular style construction that allows for easy expansion as system demands increase.

Reverse osmosis treatment without pretreatment for iron and manganese removal may not always be successful, so the technology was piloted to prove the concept would work. The pilot demonstrated that the water source was a great fit for direct treatment by reverse osmosis. In addition to iron, manganese, and hardness removal, softening membranes have an added benefit of removing other contaminants, such as nitrate, which is always a concern with shallow alluvial aquifers in agricultural settings. Nitrate levels are currently below the EPA's MCL, but test drilling showed elevated levels near the well field.

Not all membrane equipment suppliers are advocates of direct treatment, and so to ensure a successful project, ILRW decided to procure the membrane equipment prior to final design. The equipment procurement process allowed ILRW to make a selection of the equipment manufacturer based on qualifications, construction cost and operating costs, and allowed the equipment manufacturer to join the design team for final design.

The project was bid at the beginning of the pandemic (April 23, 2020) with very competitive bids. Six bids were received on the project with all bids being within 5.5-percent of the low bidder. The project was awarded to John T. Jones Construction Company on June 26, 2020, and substantial completion on the project was granted on January 25, 2022.

While direct treatment with softening membranes is not uncommon in and of itself, this project was unique in that it utilized shallow alluvial wells located approximately 2.5 miles away from the treatment plant. Due to the long raw water pipeline, ILRW and DGR determined that best practices would be to include a means to pig (clean the inner walls of pipes) the raw water pipeline in the final layout.

Based on the pilot water quality results and operating pressures, a hybrid skid was designed which utilized two different styles of membranes in each stage to target different contaminants. The RO skid was also designed for two half-sized trains on one frame to minimize the footprint and reduce overall capital costs. The half-sized trains allowed the plant to operate for a longer duration during low demand and minimize the amount of water wasted during the raw water pipeline flush period between startups/shutdowns. Thirdly, two treatment trains on one skid allowed for redundancy of the treatment equipment.

Treated water quality from the new Osgood WTP is summarized in the following table:

As indicated in the table above, the Osgood WTP produces high quality water for the customers of ILRW, a quality unmatched by most water systems. The water quality produced by Osgood is equivalent to the water quality produced by ILRW’s other water treatment plant, providing customers with consistent water quality regardless of water source. The consistent water quality has significantly reduced taste and odor complaints because the use of other bulk water sources has been significantly reduced. Osgood has reduced ILRW’s dependency on outside water sources, reduced operational costs, and set ILRW up to provide water for future demand growth.

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Treatment Plant & Well Exploration

July 29, 2021

Treatment Plant & Well Exploration

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Water System Improvements
add capacity on existing site

Osceola County Rural Water System Constructs
Treatment Plant and Adds Ground Storage Reservoir

Project Owner:
Osceola County Rural Water System

Key Experience:

  • Maintaining the use of existing facilities during the construction of the new water treatment plant on the same site
  • Surface resistivity aquifer testing to efficiently pinpoint high capacity wells

Key Features:

  • 2,400 gpm water treatment plant for iron and manganese removal
  • 1 million-gallon glass-fused steel ground storage reservoir
  • 750 kW standby generator

Osceola County Rural Water System (OCRWS) provides service to 3,200 customers in five counties of Northwest Iowa. OCRWS continues to see increasing water demands from ag and confinement livestock facilities, industrial users and municipalities. OCRWS maintains two water treatment plants that serve the North Phase and South Phase of the rural water system. During 2017, OCRWS experienced water demands that exceeded their South Phase Water Treatment Plant (WTP) capacity, which confirmed the need to move forward with expansion of the facility.

The existing South Phase WTP was constructed in the early 1980’s, with a self-contained aeration/detention/filtration system called an Aerelator®. The existing treatment equipment had reached the end of its useful life, and there was no way to rehab the existing equipment while maintaining treatment for the South Phase. Additionally, the existing WTP capacity was unable to meet OCRWS’s growing water demands, so OCRWS decided to construct a new South Phase WTP.

DGR Engineering (DGR) worked closely with OCRWS to design a new WTP to target iron and manganese removal from shallow groundwater source near the site. The new WTP was designed on the existing WTP site to minimize the project footprint and avoid additional land purchase. With the WTP location being highly visible just off IA Hwy. 10, OCRWS and DGR worked together to develop a design that not only met their water quality and capacity needs, but was also aesthetically pleasing. The new treatment process includes aeration, detention, and filtration using a gravity filter arrangement, and will increase OCRWS’s treatment capacity from 750 gpm to 2,400 gpm.

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OCRWS also needed additional source water capacity to utilize the treatment capacity of the new WTP. DGR used a surface resistivity testing program to generate multiple snapshots of the aquifer depth and production capacity. Resistivity testing uses a line of electrical probes to quickly estimate soil characteristics, without the time and expense of test drilling. The testing provides a series of graphs like the one shown below. It allowed OCRWS to gather aquifer information on hundreds of acres of potential well sites with 3 days of field work and quickly identify the highest probability areas for high capacity wells. The results of the graphs were verified with test drilling, and two new well sites were identified in the thickest and most productive areas of the aquifer.

Increasing demands at the new WTP made additional on-site storage necessary. A 1 million-gallon glass-fused steel ground storage reservoir was constructed to accommodate these needs. The additional finished water storage on-site will also give OCRWS flexibility in how they choose to operate the facility.

The total construction cost of the new WTP project was $7.8 million, which was financed using a combination of Iowa State Revolving Fund (SRF) loan and private funding. The SRF funding package included a forgivable SRF loan for standby power generation. DGR also helped OCRWS navigate SRF’s American Iron and Steel requirements. The new improvements to South Phase water source will allow OCRWS to meet current and future water demands while providing their customers with reliable, high quality water.

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Water System Expansion

May 4, 2021

Water System Expansion

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Water system expansion project
adds customers and improves system

Kingbrook Rural Water, Inc. Implements Long-Range Plan by
Improving System Performance and Serving New Customers

Project Owner:
Kingbrook Rural Water, Inc.

Key Experience:

  • Completion of a long-range plan spanning several decades and multiple projects to interconnect water sources
  • Optimized treatment plant performance by moving chemical injection points and adding finished water storage
  • Large rural water pipeline project that extends service to new members and improves system capacity

Key Features:

  • USDA Rural Development funding, including grant and low-interest loan, saving client over $4 million in interest payments
  • 215 miles of pipe 1½” to 16” in diameter extending service to 260 new customers
  • New 630,000-gallon bolted steel storage tank

Kingbrook Rural Water, Inc. is a regional water provider in eastern South Dakota, serving approximately 4,950 residential, livestock, and commercial users in more than 11 counties. They serve customers from three different water treatment plants located approximately 50 miles from each other. The treatment plants are located in rural areas near the small towns of Bruce, De Smet and Chester, SD. The original system construction happened in the late 70’s and early 80’s. All three treatment plants were expanded in the 90’s and early 2000’s to meet their growing needs.

In the mid-2000’s, DGR Engineering (DGR) and Kingbrook began developing a long-range plan to interconnect their three treatment plants with large diameter transmission mains. The goal of the plan was to provide another level of backup at each treatment plant in case of an emergency. This emergency planning was in addition to the typical approach for systems to have standby generation, backup pumps, etc. Another goal of the plan was to provide operational flexibility by having two sources that could serve any of their subsystems. Each year, an annual planning event is held to review system operations, new growth trends, and changes in existing customer demands. The plan is updated and modified to meet the current and future needs of the system.

Approximately every four to five years, these plans are combined into a project that not only improves the system for existing customers, but also extends rural water service to new customers. Conducting systematic expansion projects results in regular improvement of the system. It also allows the utility to make the most efficient investments in their system by taking advantage of low-interest loans, grants, and economies of scale when bidding out multiple improvements and new connections as one large project. In the past 15 years, Kingbrook has installed about 50 miles of transmission mains between their treatment plants, but still needed about 25 miles between Bruce and De Smet to complete the long-range planning goal of connecting their water treatment plants.

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Kingbrook began planning their current expansion project in 2015. Tremendous demand for new service connections made this expansion project the largest expansion project ever undertaken by Kingbrook. Much of the additional water demand was located within the De Smet plant service area that couldn’t be met with the existing system’s transmission capacity. Previous projects had increased elevated storage capability in the De Smet plant service area and connected with the Chester plant. But more capacity was needed to serve the new customers.

Our Approach
DGR began by helping Kingbrook optimize the De Smet treatment plant. Highly variable iron concentrations from their north well field made chemical dosing problematic. Kingbrook optimized the treatment efficiency of the plant by changing oxidants and moving the chemical dosing locations. These changes extended the filter runtime, reduced the overall chemical requirements of the plant, and increased production capacity.

Next, the existing storage capacity at the De Smet treatment plant only had about three and a half hours of peak demand storage, which made plant operation difficult. Kingbrook selected a two-phase process to build one 630,000-gallon tank now, which will increase on-site storage to about eight hours, and build a second tank as part of a future project, when demand increases.

Finally, DGR designed pipeline that would serve the new customers and complete the interconnection to Kingbrook’s third water source near Bruce. When complete, this project will add approximately 190 miles of pipe for system improvements and new services, as well as approximately 25 miles of 12, 14, and
16-inch diameter pipeline to interconnect the Bruce plant with
the De Smet plant.

The project is was finished in the summer of 2019. This project
not only meets the needs of new customers who signed up on
this expansion project, but it also achieved a major milestone
of Kingbrook’s long-range planning – the interconnection of
their water sources to improve system reliability and flexibility
of operations.

Water Treatment Plant

October 12, 2018

The rural residents around North Sioux City and Elk Point South Dakota can find as much water as they want, just by sinking a well anywhere in the Missouri River Alluvial Valley.  The problem is that the “good water” in this area, which is lower in iron and manganese, is laced with radium.  Rural communities like Wynstone and Sandy Meade were faced with the challenge of Radium removal to protect their customers.

Clay Rural Water System partnered with these developments and the surrounding rural customers to bring Radium Free water to over 500 homes.  These residents dealt with contaminated drinking water for decades, and now have confidence in the water they are drinking. DGR Engineering worked with Clay Rural Water System to construct a reverse osmosis water treatment plant to take water with raw water combined radium 226 + 228 of 12.4 pCi/L down to below detection limits of <1.0 pCi/L.   These customers have been receiving this safe drinking water now for over a decade.

The plant treats the deep well water directly with reverse osmosis without pre-treatment, even though the raw water has high iron and manganese levels.  This innovative treatment approach saved significant construction and operational costs for the water system.