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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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New Water Distribution System

July 25, 2022

New Water Distribution System

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Big Solutions for a
Small Town Water System

Project Owner:
City of Revere, MN

Key Experience:

  • Successfully navigated the COVID-19 pandemic, with four separate construction contracts and 100% remote funding agency coordination
  • Secured 86% grant through USDA RD, and DEED SCDP funding
  • Replaced water meters with remotely read automatic reading system. High accuracy meters increased revenue and decreased water loss
  • Replaced aging ACP pipe with new PVC - reducing public health risk and greatly reducing risk of water main breaks

Key Features:

  • Entirely new water distribution system
  • All new water meters
  • Demolition of existing water tower
  • Improved water quality with connection to Red Rock Rural Water System

The City of Revere, MN faced a familiar challenge for rural communities in the upper Midwest. The City’s aging water infrastructure was in need of upgrades. But with a declining population and many residents on a fixed income, there were limited resources to pay for costly repairs and maintenance of their failing water system. The water mains, valves and hydrants in the community needed to be replaced, the water tower needed to be repainted, and there was no treatment or back-up supply for the one and only well in town. In need of assistance, The City reached out to DGR Engineering (DGR) as a trusted water professional in the region to help them find a solution.

Aging Water Infrastructure
The existing water infrastructure was installed in the mid-1900s and included water mains which were constructed using asbestos-cement pipe (ACP), which was approaching the end of its useful life. As ACP ages it becomes brittle, making it difficult to repair. With the presence of asbestos fibers in the pipe material, ACP can be a health risk when the pipe is cut during repairs or when cracked. The City was also experiencing a water loss of over 18%. The town’s mechanical water meters were over 40 years old and were suspected to be contributing to the system’s water loss, in the form of unmetered water.

The City’s water tower was over 70 years old with a coating system that was in poor condition and showed visible signs of pitting in the steel. The most recent water tower inspection recommended a complete blast and re-coating of the tower, which would require special consideration for lead paint removal and other improvements to bring the structure into compliance with OSHA safety standards.

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Alternative Water Supply
The City’s water supply consisted of a single production well drilled in 1982 at a depth of approximately 200 feet. Although the well was still in good operating condition, there was no back-up well and no standby generation to ensure continuous water supply in the event of a power outage or failure/maintenance of the existing well. The Minnesota Department of Health imposed a requirement on the City to obtain a backup water source, either by drilling a second well or connecting to a regional water system.
The City’s water source was untreated except for chlorine injection for disinfection. The water quality of the existing well met all state and federal primary drinking water standards, but there were several contaminants that exceeded the non-mandatory secondary drinking water standards. High concentrations of iron, sulfates and total dissolved solids created taste, color and odor concerns within the community. The City needed a solution that not only provided a redundant water supply, but also improved water quality.

Funding Assistance
The City wanted an engineering study that would identify necessary water system improvements and establish a budget for financing those improvements. DGR assisted the City in securing a Special Evaluation Assistance for Rural Communities and Households (SEARCH) grant through USDA Rural Development to fund 100% of the cost of a Preliminary Engineering Report (PER) and Environmental Assessment (EA). The report recommended full replacement of the water distribution system, new water meters with an automated meter reading (AMR) system, demolition of the water tower, abandonment of the existing well and chemical feed building, and a water service connection to the regional rural water system, Red Rock Rural Water System.

With an estimated price tag of over $1.1 million, and a small population, The City needed a comprehensive solution to help make the water system improvements affordable for its residents. The City's median household income made it eligible to receive a grant through the Minnesota Department of Employment and Economic Development’s (DEED) Small Cities Development Program (SCDP) for public facility improvements.

The SCDP public facility grant was packaged with financing through Rural Development’s Water and Environmental Program that included additional grant funding and a low interest loan. The City’s final funding package included over 86% grant, keeping the project costs affordable for the town’s residents.

 

Project Design and Construction
With funding secured for the project, The City asked DGR to proceed with final design of the improvements recommended in the PER. Because of the unique nature of each type of work, the final design entailed separate construction contracts for the water distribution system replacement, water metering system replacement, water tower demolition and the connection to the Red Rock Rural Water System.

The water distribution contract was bid in February of 2020. By May of 2020, the water distribution contractor started construction. By the end of the year, all water main and services had been replaced, new water meters had been installed and the system was connected to Red Rock’s system. Once the connection was made to Red Rock, Revere residents said their final goodbyes to the City’s 73-year-old water tower.

Today, The City’s residents enjoy high quality water that comes to them in a new and reliable distribution system. City staff rest comfortably knowing the risk of water main breaks during cold winter nights is now greatly reduced, and customers are being accurately billed for usage. Thanks to a generous funding package, it was all done with a reasonable impact to user rates that was well received by the City’s residents.

In the end, the City of Revere completed a project that met their objectives, budget, and schedule. DGR staff is proud to have played a key role in this successful project.

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Site Development, Utility Improvements

July 25, 2022

Site Development, Utility Improvements

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public support for
public safety in alton

Project Owner:
City of Alton, IA

Key Experience:

  • Long term coordination with the City of Alton to plan for the future needs of the area
  • Successful coordination with local contractors
  • Local design partnerships with CMBA and EDA for the building addition project

Key Features:

  • Long-term City planning outlook- 2015 street project, 2022 Fire Station Addition project
  • Community support, $2M bonding bill supported by 97% of voters
  • Local contractors bids add to the community feel

DGR Engineering (DGR) continues to support the City of Alton, IA in planning and design for their long-term infrastructure needs, including a new fire station. As part of that process, a multi-phase plan for infrastructure projects was developed, splitting the project work into two phases to meet budgetary and approval constraints. Phase 1 (2015) involved a street reconstruction project, including updated sanitary sewer and water infrastructure with new road surfacing (PCC). Phase 2 (2021-22) included new (PCC) driveway and sidewalk, grading and building utilities adjacent to the new building addition.

Driveways, sidewalks and utilities for the 11th Street project (2015) were planned while keeping in mind the challenging ADA site for the future fire department expansion project (2021).

To add to the public support sentiment that surrounded this project, both publicly bid projects featured area contractors. The 2015 street project was completed by Jellema Construction of Alton, and the building general contractor was Poppma-Sikma of Sheldon. The design group included DGR as the civil engineering consultant for both projects, while the building addition (2021-22) was designed by CMBA Architects and Engineering Design Associates (EDA) as design partners.
Based on the design, bidding and construction time frames, the building addition project experienced the early effects of recent economic inflation. The City and design team selected project materials and changes as needed to meet the project budget. The project overwhelmingly passed in the bonding vote, including an additional parking paving bid alternate that was not included in the final project.

Challenges
As with most projects, challenges presented themselves throughout the course of the two projects. The primary concern from a site perspective was constructing a single floor elevation building addition adjacent to a roadway with 4' of fall, while maintaining fire truck passable driveway slopes and ADA required sidewalk grades.

The City provided early indication of their future building plans, allowing DGR engineers to design street grades that would meet the municipal street needs and allow for an ADA accessible route to the new community asset.
In the end, successful communication, planning and flexibility culminated in two successful projects for the community of Alton, resulting in a singular infrastructure upgrade.

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DGR designed a new lift station, new sanitary sewer, water mains and the associated service lines as well as a storm sewer system to collect stormwater. The stormwater was routed to the south end of Rushmore Drive to the sedimentation basin designed as part of the project. The sedimentation basin has a system in place to help collect trash washed from the streets and to contain sediment and oils from the roadway. This allows the City to collect that material and dispose of it, rather than have it carried into Splitrock Creek.

DGR teamed with Confluence to facilitate streetscaping and the sedimentation basin landscaping.

The sedimentation basin was a unique feature to this project. It was designed to slow the discharge of stormwater to Splitrock Creek in smaller rain events, but it also has the ability to be overtopped at the bottom in larger rain events without causing damage to the system.

As the City of Brandon grows, the basin will help to meet upcoming MS4 (Municipal Separate Storm Sewer System) EPA requirements that will be placed on the City.DGR assisted the the City in acquiring the land needed to construct the sedimentation basin and relocate the City’s lift station that serves the area. The decision was made to relocate and construct a new sanitary sewer lift station on the same parcel that would contain the sedimentation basin. The new lift station replaced some aging pumps and equipment, and employees will no longer need to climb down into a confined space. In addition, an on-site back up generator was added to provide instant backup in the event of a power outage.

During construction, DGR provided on-site construction observation to ensure the work complied with the design requirements and to work with residents, answer their questions and address their concerns. Temporary mailboxes were added near the post office for the project and when the project was complete, Cluster Box Units (CBU’s) were installed, eliminating mailboxes at each residence.

Phase II is planned to be constructed in 2023 and Phase III construction is planned for 2025.

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Neighborhood Reconstruction

July 25, 2022

Neighborhood Reconstruction

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Making Neighborhoods Better.

Project Owner:
City of Brandon, SD

Key Experience:

  • Project Phasing
  • Community Communication
  • Open House Informational Meetings
  • Easements

Key Features:

  • Water and Sewer Line Replacement
  • New Storm Sewer
  • New Curb and Gutter
  • New Asphalt Pavement
  • Sidewalk and ADA Improvements

In 2018, the City of Brandon selected DGR Engineering (DGR) to assist the community with the reconstruction of approximately 30 city blocks of the Rushmore Area in the southeast part of the city. The streets had outlived their useful life and the roadway was starting to degrade quickly in certain areas. Part of the reason for the rapid degradation of the street surface was the lack of storm sewer in the neighborhood. In addition, the water and sewer lines were in need of replacement due to their age and condition. Additional storm sewer, new curb, gutter and asphalt pavement, as well as a new 4 ft. wide sidewalk and ADA improvements, were also included.

The first steps in the process were to survey the entire project area, coordinate with staff to define the scope, and develop cost estimates for the work that needed to be done. Potential project phases were developed for the project to meet the financial needs of the City. Phasing of the project that would best fit the City's budget was determined, and then DGR began to design the first phase.

Communication was critical to keep residents informed. Letters were mailed out to residents prior to a survey taking place. A public open house was held to give residents details of the project and inform them of easements that would be needed. Easement documents were prepared and sent to property owners. DGR conducted many personal meetings with residents to discuss and obtain easements to facilitate the project.

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DGR designed a new lift station, new sanitary sewer, water mains and the associated service lines as well as a storm sewer system to collect stormwater. The stormwater was routed to the south end of Rushmore Drive to the sedimentation basin designed as part of the project. The sedimentation basin has a system in place to help collect trash washed from the streets and to contain sediment and oils from the roadway. This allows the City to collect that material and dispose of it, rather than have it carried into Splitrock Creek.

DGR teamed with Confluence to facilitate streetscaping and the sedimentation basin landscaping.

The sedimentation basin was a unique feature to this project. It was designed to slow the discharge of stormwater to Splitrock Creek in smaller rain events, but it also has the ability to be overtopped at the bottom in larger rain events without causing damage to the system. As the City of Brandon grows, the basin will help to meet upcoming MS4 (Municipal Separate Storm Sewer System) EPA requirements that will be placed on the City.

DGR assisted the the City in acquiring the land needed to construct the sedimentation basin and relocate the City’s lift station that serves the area. The decision was made to relocate and construct a new sanitary sewer lift station on the same parcel that would contain the sedimentation basin. The new lift station replaced some aging pumps and equipment, and employees will no longer need to climb down into a confined space. In addition, an on-site back up generator was added to provide instant backup in the event of a power outage.

During construction, DGR provided on-site construction observation to ensure the work complied with the design requirements and to work with residents, answer their questions and address their concerns. Temporary mailboxes were added near the post office for the project and when the project was complete, Cluster Box Units (CBU’s) were installed, eliminating mailboxes at each residence.

Phase II is planned to be constructed in 2023 and Phase III construction is planned for 2025.

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Wastewater Treatment Facility

July 25, 2022

Wastewater Treatment Facility

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Schleswig Wastewater Treatment Facility Moves Out of Town

Schleswig had two major decisions to make:
what type of treatment technology to construct,
and where it should be constructed.

Project Owner:
City of Schleswig, IA

Key Experience:

  • Selecting a suitable site for a new treatment plant involved coordination with:
    - Local landowners willing to sell land for a reasonable cost
    - County engineers to provide improved site access on minimum maintenance roads
    - Electrical utilities to provide new electrical service to the site
  • Schleswig received funding through the WWDWTFAP in the first year it was signed into legislation; a total of $775,000 in grant was awarded to six projects in Iowa in the first year

Key Features:

  • New WWTF designed to treat:
    - Average wet weather (AWW) flow
    of 0.234 million gallons per day (MGD)
    - BOD load of 276 lbs/day
    - Total Kjeldahl Nitrogen (TKN) load
    of 58 lbs/day
  • Total construction cost of $3.5 million. The project was financed through:
    - SRF loan program including
    Planning & Design Loan
    - $300,000 CDBG grant
    - $100,000 Wastewater and Drinking Water Treatment Financial Assistance Program (WWDWTFAP) grant

The City of Schleswig, Iowa is a small, German-heritage town located just north of Denison on U.S. Highway 59. To treat its wastewater the City operated a 3-cell aerated lagoon facility located in the south part of town that was originally built in 1960, with upgrades made in 1975 and 1999. Since its construction, the community has continued to expand around the treatment facility, including a golf course directly to the west and a residential housing development immediately south. Each spring as the ice would melt, the lagoons would turn over and create an odor issue throughout town, while the floating aerators provided a constant humming sound as background noise to any activities taking place near the facility.

In 2017 the City was issued a new NPDES discharge permit which contained more stringent ammonia limits as well as new E. coli limits. Similar to many small communities in Iowa, Schleswig’s aging lagoon treatment facility could not meet these new limits. It was clear that innovation was needed; hence, the City retained DGR Engineering (DGR) and began planning a wastewater treatment facility (WWTF) improvements project.

In modifying their WWTF, the City had two major decisions to make: what type of treatment technology to construct, and where it should be constructed. With input and advice from DGR, the City decided that the best option would be to build a LemTec ™ treatment system, and to move it out of town.

The City was able to purchase 7.35 acres located 2.5 miles east of town to build its new treatment facility. The LemTec™ system was chosen based on its relatively small footprint, ease of operation, and low capital and operation and maintenance costs. Ultimately, the LemTec™ system allowed Schleswig to meet the more stringent permit limits utilizing a robust, easy-to-operate, affordable technology.

The project included a new inlet screening building with a vertical mechanical screw screen and compaction system intended to remove, wash, and compact solids in the wastewater stream larger than 0.25 inches. The screening system is followed by a duplex submersible pump lift station, both located at the existing treatment site. The lift station pumps the screened influent through 2.5 miles of 8” forcemain to the new treatment site.

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Wastewater graphic

Many WWTFs that struggle to meet ammonia limits have more issues in the cold winter months than in the summer. This is because at a wastewater temperature of 60°F, the nitrification rate at which bacteria treat ammonia begins to decline, and at a wastewater temperature of 50°F the treatment efficiency is reduced by half.

The LemTec™ system helps combat this phenomenon in two ways: first, the insulated lagoon covers help retain heat in the system; second, the fixed media in the polishing reactors provides greater surface area to allow a larger population of nitrifying bacteria to grow and treat ammonia.

The LemTec™ system at the new treatment site consists of two aerated treatment lagoons which are covered with insulated, floating covers to retain heat and increase treatment efficiency.

The aerated lagoons are followed by small polishing reactors which contain fixed media to provide additional ammonia treatment. Effluent from the polishing reactors is disinfected through a UV disinfection system for treatment of E. coli prior to discharge to the receiving stream.

The system began initial start-up in mid-December 2021, and after a slow start-up process due to a cold winter and spring, is currently treating the wastewater to non-detectable ammonia concentrations (< 0.5 mg/L).

The City is currently working on filling in one of the old treatment lagoons, and the floating aerators and baffles were removed from the other treatment lagoon as a part of this project. A walking trail winds past the old treatment lagoon, and now instead of nuisance odors and loud humming from the floating aerators, residents can enjoy a serene view of a pleasant, quiet water feature while their wastewater is being effectively treated outside of town.

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