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Electrical Power

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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Upgrading Communications

July 29, 2021

Upgrading Communications

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Fiber optics chosen as optimal
solution for L&O Power Cooperative

Project Owner:
L&O Power Cooperative

Key Experience:

  • Specified and procured all the components for this project, including fiber optic cables, hand holes, equipment racks, patch panels, Ethernet switches, fiber test equipment, patch cables,
    and more
  • Locating services using GIS
  • Installation included all cable plowing, trenching, boring, and pulling required for each L&O site as well as the 4.5-mile underground project
  • Tested the functionality of the fiber network, providing sufficient data to be utilized as a baseline for future troubleshooting

Key Features:

  • Privately owned and secure high speed fiber optic data network
  • Optical ground wire (OPGW) serves as both a communications path and bonds adjacent towers to earth ground to shield the high-voltage conductors from lightning strikes
  • Detailed GIS mapping of transmission lines and underground facilities

Reliable data communications are a necessity to all industries, and the utility industry is no exception. In critical moments, dependable communications are imperative. A poor connection can be the difference between a 5-minute or an extended electrical outage. No one wants an extended outage, extra expense, or inconvenience of having to commit additional resources to what should have been a simple solution. In addition, certain scenarios can put first responders or the general public at risk.

Realizing the risks of a less-than-reliable communications network, a long-standing client of DGR Engineering (DGR), L&O Power Cooperative (L&O), was determined to improve communications on its electric transmission system. L&O has utilized wireless radios on its system since the 80s and unlicensed 900 MHz digital Ethernet wireless radios since 2005. The radio system performed well for years but was designed as a budget-friendly way to connect sites over long distances while sending limited amounts of data. The need for constant uptime, along with an exponential rise in data traffic over recent years is exceeding the technology’s limitations.

DGR engineers explored different solutions. Radio technology with more data throughput such as Wi-Fi or microwave could be deployed. Microwave radios proved econ-omically unfeasible. Standard Wi-Fi technology could not meet the distance requirements and would require additional repeater sites and devices to meet L&O’s needs. Cellular radio options were reviewed, but paying for data and exposing critical data to the outside world was seen as a last resort or backup plan. A private fiber optic network owned exclusively by L&O became the solution that met both current and future needs. Fiber is reliable, secure, and offered data capacity that exceeded L&O’s projected future needs.

DGR recommended utilizing L&O’s existing transmission lines as the backbone for their fiber network, replacing the static wire on most lines with an Optical Ground Wire (OPGW) design. OPGW is a stranded electrical conductor with a steel tube core. The steel tube is then filled with numerous fiber optic strands. L&O understood that pursuing this solution would take longer to deploy but would be in their best interest long-term. As this OPGW infrastructure is built out, L&O intends to utilize existing wireless radios for backup communication in the event the OPGW line is compromised.

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As part of the capital improvements study that DGR recently performed for L&O, it was identified that many of their lines were at the end of their useful life and due for replacement. The timing of the line replacement lined up well with their need for communication infrastructure improvements. DGR was tasked by L&O to design a new transmission plant to include OPGW. The remaining lines, yet to be completed, will require existing static wires to be replaced with OPGW or installation of a new underground fiber line to connect remaining terminal sites. The OPGW will be the backbone of the L&O communications infrastructure for the foreseeable future.

With the OPGW plan in place, DGR proposed the installation of a new 4.5-mile underground fiber line to connect their headquarters building to the OPGW network.

DGR’s team determined the optimal routes, materials, and cable locating requirements. DGR also consulted with local utilities to optimally navigate rights-of-way where possible. DGR’s team acquired the necessary permits from the Iowa DOT and Lyon County. No DNR permits, encroachment agreements, or new easement acquisitions were necessary for this particular project. The route consisted of utility rights-of-way, existing utility easements, and private property owned by L&O.

Underground cable location processes are necessary for all utilities that own and operate underground facilities. After investigation of contracted locating services options, L&O ultimately decided to take on the locating responsibility themselves. With the help of precise Global Positioning System (GPS) equipment that integrated into GIS and some additional effort during installation, L&O could perform locating services, accurate to within a few inches. The Owner felt comfortable with this amount of accuracy and appreciated the simplicity of the idea. All the underground cable installed was either armored or included a tracer wire to accommodate traditional cable locating practices as well.

The team at DGR developed plans and specifications two separate contracts the construction of the underground project; one for underground cable installation and the other for fiber splicing. The scope of the installation included all rural area cable plowing, trenching, boring, and pulling required for each L&O station site as well as the 4.5-mile mainline project. The installation contractor was able to substantially complete their scope of work in approximately one week while encountering only minor issues during construction. The fiber splicing connected all the OPGW system to underground cables as well as interconnecting fiber patch panels. DGR specified and procured all the components for this project, including fiber optic cables, hand hole, pedestals, equipment racks, patch panels, Ethernet switches, test equipment, patch cables, and more.

Testing the fiber optic cable upon project completion is a key milestone for this project as well. DGR’s ability to test the functionality of the fiber network provides L&O with sufficient data to be utilized as a baseline for future troubleshooting.

The DGR team was able to perform the necessary project design, permitting, specifications and procurement, incorporation of GIS, and complete the construction on time. GIS was originally outside the scope of this project, but in the end, contributed much value in construction, mapping and locating efficiencies. The GIS team at DGR was able to quickly develop a GIS solution, and it has been an invaluable tool. Overall, the DGR team was able to complete this job on time, on budget, and overcome numerous unforeseen challenges in completing the project.

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Distribution Conversion

July 29, 2021

Distribution Conversion

before after

Redwood falls project
Improves equipment, safety and aesthetics of Downtown Area

Project Owner:
Redwood Falls Public Utilities

Key Experience:

  • Responsibility and involvement throughout the project, from initial planning and design to construction administration and contract closeout
  • Development of a multi-year plan for staged construction of the improvements
  • Coordination with private communications utilities including joint use of excavations

Key Features:

  • Replacement of old overhead infrastructure with new underground infrastructure, to increase reliability and improve aesthetics
  • Eliminated public safety concern of old transformer platform structures

The electric distribution lines in the downtown alleys of Redwood Falls, MN consisted of large overhead structures which included transformers mounted on platforms. Due to concerns with the age and condition of the structures, along with safety clearances to energized equipment and conductors, a project was undertaken to replace the old infrastructure with new underground lines and associated padmount equipment. In addition, these improvements would improve the overall attractiveness of the area.

The project was split into two phases to allow for completion over two construction seasons. Phase 1 included four blocks of downtown area, and the second phase included seven blocks. In addition to burying the overhead primary circuitry, the project also converted most of the overhead secondary circuitry associated with the conversion area to underground.

DGR Engineering (DGR) developed a full design for the new underground circuitry, including equipment and cable sizing, equipment locations, line routes, and material lists. Bidding and contract documents for construction of the improvements were developed which included detailed design drawings, staking sheets, and technical specifications. DGR worked with utility staff to determine where new easements would be needed for placement of padmount equipment.

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The project was designed to allow for directional boring of the cables wherever practical, and for trench excavation when needed, due to the quantity and/or location of underground cables and ducts. Sections of pavement were removed when required and subsequently replaced with new concrete after the installation of new raceways was finished.

Contractors completed the boring, excavation, and surface repair work; and the installation of raceways, primary and

secondary cables, box pads, ground sleeves, and secondary boxes and cabinets. The utility completed the installation of padmount transformers and switches, primary cabinets, cable terminations, and meters. The utility also performed all equipment cutovers and energization, and removed the existing overhead lines and related facilities. The completed project resulted in a safer and more aesthetically pleasing downtown area that was also up to current standards for infrastructure and reliability.

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Street Lighting Improvements

July 19, 2021

Street Lighting Improvements

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Hawarden's Street Lighting
Gets a Makeover

Project improves energy efficiency and aesthetics

Project Owner:
City of Hawarden, IA

Key Experience:

  • New LED lighting pattern meets and exceeds the brightness of the existing lights
    Appearance of the lighting on the roadway is much more uniform than the legacy lighting
  • Overall number of street lights was reduced

Key Features:

  • Improved roadway visibility
  • Reduced operating costs
  • Enhanced appearance along Highway 10

The legacy street lights along Highway 10 in Hawarden, Iowa had reached the end of their useful life. Many of the mast structures were beginning to corrode and a few, which were too old for replacement parts, had been removed completely, resulting in poorly lit areas along the street.

The City wanted to replace the old lighting system with a modern LED based system to reduce operating cost. In addition, they preferred to use decorative style lighting units which would enhance the aesthetics of the downtown area, and match what had been utilized in other parts of the city.

For the residential area of the street, cobra head fixtures were desired. This type of fixture is used to reduce cost while also providing improved lighting levels.

To begin the process, existing emitted light patterns were modeled using VisualTM 2012, an Acuity Brands Lighting software package, to determine the photometric patterns of the existing lighting system. The City wished to maintain or exceed current lighting levels. Once existing levels were determined, the new street lighting system was designed based on the Illuminating Engineering Society’s (IES) RP-8 guidelines and to meet or exceed existing lighting intensity levels. After the layout was completed, construction plans were developed. Preparations were made to hire a contractor to install the system along with the related foundations, conduit, wiring, and grounding.

The City is pleased with the new lighting system performance improved intensity and uniformity, as well as the reduced energy consumption of the system.

Click here to read this story in the newsletter.

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Turbine Control System Upgrade

May 6, 2021

Turbine Control System Upgrade

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Turbine control system upgrade provides new technology and increased reliability

Project Owner:
Marshall Municipal Utilities

Key Experience:

  • Involvement throughout the project including preliminary feasibility, design, bidding, construction administration, commissioning, and
    project closeout
  • Integration of a new generator control system and relaying with existing substation equipment
    and relaying
  • Modernization of customer assets to improve reliability

Key Features:

  • Control system upgrade/replacement for a 16.5 MW, 13.8 kV turbine generator set
  • Upgrade from original electromechanical generator relaying to modern
    digital relaying
  • Replacement of motor control center and
    related equipment
  • New remote workstation in the MMU dispatch center allowing for full access to operate and monitor the turbine generator set

Marshall Municipal Utilities (MMU) owns and operates a 16.5 MW turbine generator set that is interconnected to their Saratoga Substation at 13.8 kV. The turbine generator provides a source of MMU revenue through a contract for its available capacity with their power supplier. In addition, it can be called upon to provide emergency power to the MMU distribution system in the event of a system outage.

The turbine generator set was originally installed in 1968, and in the mid-1990’s the original controls were upgraded to an early generation microprocessor-based system. The technology and parts for the existing control system were becoming obsolete, maintenance was proving to be more problematic, and it was difficult to find support for the aging system. As a result, MMU was interested in upgrading the control system to one with the latest technology in order to maintain and improve upon its reliability going into the future.

DGR Engineering (DGR) developed design specifications and drawings to allow for the system upgrades to be procured through a municipal bid process. The contract was awarded to HPI, LLC of Houston, Texas. Project meetings were held bi-weekly between HPI, MMU, and DGR to review decisions and progress concerning the new control panels, software, and hardware details.

The project included full removal and replacement of the existing control panels within the turbine building control room. A local HMI touchscreen was included in the turbine control panel along with a remote workstation in the MMU dispatch center, each of which provides operators with full access to the operating and monitoring parameters of the turbine. A new fuel control valve was installed to interface with the control system and provide precise control of fuel flow. Additionally, the original motor control center (MCC) was replaced with a new MCC panel which included interfaces to the new control system.

The existing electromechanical protective relaying was replaced with modern digital relaying to make it consistent with other MMU system protection equipment. This allowed for the protection to be seamlessly integrated to the existing MMU SCADA network.

The turbine generator set was removed from service for approximately two months to allow for removal of the old equipment and installation and wiring of the new equipment. DGR developed settings for the new protective relaying and was involved throughout the startup and commissioning of the new control system equipment.

The electrical project was completed in the summer of 2018, allowing for the resumption of commercial operation.

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