Subscribe to our Newsletter

Categories

Uncategorized

Site Development, Utility Improvements

July 25, 2022

Site Development, Utility Improvements

image2

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.

IMG_9858
IMG_9302

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.

IMG_1247

Wastewater Treatment Facility

July 25, 2022

Wastewater Treatment Facility

DCIM100MEDIADJI_0737.JPG

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.

IMG_2560
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.

IMG_2704

Trent Bruce named 2022 Engineer of the Year by SDES-Eastern Chapter

March 3, 2022

Congratulations to DGR’s Trent Bruce, PE on being named Engineer of the Year by the South Dakota Engineering Society Eastern Chapter! The honor was announced at the annual awards banquet Saturday evening, February 26. It recognizes SDES members who have made outstanding contributions to the engineering profession, the public welfare and/or humankind. Bruce is the head of engineering services and office manager of the Sioux Falls, SD office.

DGR Engineering Welcomes Jaidyn Elbers

January 17, 2022

Solutions Winter 2022 Newsletter

January 11, 2022

Learn about recent projects and happenings at DGR Engineering here. This issue’s cover story features Wagner, South Dakota’s new track and football facility; the new water treatment plant in Sanborn, IA; aviation weather systems (AWOS); Federal infrastructure investment funding for water and wastewater projects and more.

Read the Winter 2022 Solutions newsletter here.