An aerial view of the Rocky Creek Water Reclamation Facility.

May 20, 2021

Wastewater Project is a Paragon of Progressive Design-Build, Part 1

Working closely with the Macon Water Authority and its design partner, Haskell maximized the available budget to rehabilitate two reclamation facilities.

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Editor’s note: Haskell’s Bryan Bedell, Vice President of Water, and Mike Hoisington, Director of Project Development in the Water Division, recently took part in a panel discussion centered on the rehabilitation of two water reclamation facilities for the Macon (Georgia) Water Authority. Today we present the first of two parts of the comprehensive case study, which describes the relationships, process and budgetary and design benefits of the progressive design-build project.

 

The Macon Water Authority (MWA) dates to 1973, when it was created by an act of the Georgia General Assembly to provide public water and sewer services for the citizens of Macon and Bibb County. It owns and operates one water treatment plant and two wastewater reclamation facilities, with 1,425 miles of water mains and sewer lines and 51,000-plus metered accounts serving 155,000 customers.

The Lower Poplar Water Reclamation Facility (WRF), constructed in 1959 with its last major update in 1984, is permitted at 20 million gallons per day, while the Rocky Creek WRF, built in 1973 with the last major update in 1985, is permitted at 28 million gallons a day.

Both facilities were aging and needed significant rehabilitation. MWA created a team comprising engineering, operations and maintenance staff to select processes included in the initial scope of work. Both plants needed similar influent screening, grit removal, and de-watering equipment. Lower Poplar also needed digester improvements, Fats, Oils and Grease (FOG) receiving stations and effluent pumps.

The MWA chose to conduct the project through the progressive design-build process because its iterative approach to concurrently progressing the design detail and the construction cost estimate provides flexibility and collaboration throughout the design, quicker decision-making during concept and construction, owner control of the budget and quality control.

The procurement process was based primarily on qualifications but included pass or fail elements for safety and financial capability. Proposals included the following elements: project approach, local minority business enterprises (MBE) utilization plan, interviews, and plan to maximize scope with an available budget of $33 million.

Haskell was chosen as the design-builder in partnership with Barge Design Solutions. MWA also retained an owner’s advisor.

Given the resounding success achieved, representatives from Haskell, Barge and the MWA presented learnings and achievements from the project during the DBIA Design-Build for Water/Wastewater Conference 2021, which was held virtually because of COVID-19 precautions.

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Creating Collaboration Within the Team

Bryan Bedell, Haskell Vice President of Water

One of the things that’s central to any good design-build project is being able to create collaboration within the team. It was critical for us to have opportunities for team building so that we could get to know each other as individuals and within the overall team. One of the ways we did that was attending conferences, especially attending WEFTEC (Water Environment Federation's Technical Exhibition and Conference), which allowed the team to meet with each vendor for the specific equipment manufacturers, to weigh options and look at not only initial capital costs, but also operating challenges and solutions. Going to those conferences also provided a good opportunity for socialization – the ability to take in a baseball game or other activities – and team building on more on a personal level.

It was also important that we established early on relationships at each of the key positions. Those were the team’s senior project manager, which was Haskell Director of Project Development Mike Hoisington, with the MWA overall project manager, which was Frank Evans; our overall field superintendent with the plant operators; and the key teams out in the field. And then being able to, at an executive level, have a relationship and establish periodic meetings so that those communication channels were open throughout the entirety of the project. The establishment of those relationships was key to the project’s overall success.

The owner’s advisor has been an asset to the project from the onset. They've helped bring validity to cost estimating, schedule evaluation, and overall decisions made on the project and have been a great second set of eyes, which provided MWA with a comfort level that the design-build team is doing the things that are in the best interest of the overall authority and of the projects.

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Maximizing Capital-Improvement Budgets

Mike Hoisington, Haskell Director of Project Development

As is typical with most plants, the needs far outweigh the budget. For us to maximize that budget, we were transparent with MWA on how every dollar was spent. So, we provided multiple cost estimates for them to review. We did a conceptual estimate, a 30%, 60%, Guaranteed Maximum Price (GMP), and then one again at 100% design, just to confirm if there was any scope creep. And we did this in an open-book fashion. We presented a binder that included our estimates and the proposal backups from each of the vendors. We did a page-turn with MWA to show them how each one of their dollars was going to be spent on the project.

Another benefit of the design-build process was that we were able to do early procurement of key processes equipment. We knew that there were key structures and components that needed to be upgraded or modified. So, we narrowed those down and got proposals for each of those components based on site visits and engineers’ recommendations. We were able to procure the process equipment early, which was a benefit because, at the time of this procurement, the steel market was very volatile. We were able to lock in pricing on that equipment and not worry about cost increases through the design process. It also allowed a Barge to design around specific equipment for the project.

Reusing the existing structure in order to install new grit chambers was an example of maximizing the MWA’s budget.

Ben Adams, Vice President and Client Services Leader, Barge Design Solutions

From the design perspective, reviewing the geotechnical information and MWA's records early on was important. The findings we gathered from those sources indicated that we would have to have deep foundations for new structures. Also, there was a very shallow groundwater table. As a result, we decided that if we could utilize the existing structures to the greatest extent possible, we could maximize the owner’s dollars.

An example of this is the grit-removal process. We reused the structure in order to install new grit chambers into the sloped rectangular structures. In addition, we raised the walls of the channels and rehabilitated the channels themselves. We were also able to utilize the existing influent pump station pumps as a part of this bypass, which was yet another cost-setting measure as compared to a standalone system.

During the project, it was discovered that the Rocky Creek Aeration Basin needed significant repairs, requiring a change order. Because of the teams’ close collaboration, Haskell’s ability to build from limited designs and the use of MWA resources, the challenge was dealt with in stride.

For the Rocky Creek aeration basin, the original contract only included the replacement of the aeration basin mixer motors; however the client knew that there would potentially need to be some cleaning of solids once drained. It turns out that not only did some solids need to be removed, but there were some significant repairs that were needed for the mixer baffle plates and to the bottom slab and side slopes of aeration basins .

With this being a collaborative project, MWA forces were happy to jump in and utilize some of their equipment to help us with the evaluation and repair of the existing side slopes for the aeration basin.

Frank Evans, Maintenance Manager, Macon Water Authority

MWA utilized CCTV to examine the caverns that were found beneath the sloped end. Videos were made and shared with the design team so we could formulate a repair. The team referred to old drawings and found there were lagoons located in this area prior to the basin being built. This appeared to have led to the failure of the concrete on this end of the structure.

Ben Adams

So once our investigation was complete, we memorialized the findings, which included the recommended repairs, in a technical memorandum with sketches of repair solutions that were literally sketched on those records drawings that Frank mentioned. Ultimately, Haskell was able to implement the repairs based on that technical memorandum instead of the owner needing to compensate the design-build team with a detailed design that would be required in a bidding environment.

Pump control panels were elevated in anticipation of future flooding at the Lower Poplar Pump Station.

At the Lower Poplar River pump station, in extreme events, the adjacent Macon River can swell out of its banks and flood into the Lower Poplar site in and around the effluent pump station location. In those rare events, it becomes not only inconvenient but even dangerous to get around the plant and operate mechanical or electrical equipment. This was brought up during the construction of these improvements, and during the installation of those pumps, the design-build team and MWA discussed raising the pump control panels to an elevated surface. This is a benefit of the flexibility of being able to adapt during a progressive design-build arrangement. Ultimately, the panels were adjusted up. We also were able to recognize another very interesting and unique opportunity, in that we evaluated a clarifier walkway that was demolished and removed from another location on site and our structural engineers determine that we could use it as a catwalk to be installed to access these panels.

So, in this case, we were able to gain efficiencies in multiple ways to maximize MWA’s capital improvement budget. It's not uncommon to see design costs in the range of 12 or so percent of construction. However, in this project, with nearly $20 million of Construction-In-Progress (CIP) additions, Barge was able to support the Haskell team with the design costs of approximately 3½ percent. In a design-build, the engineers are collaboratively teaming so that we aren't worried about providing a “defensible” design. Further, MWA was able to select specific equipment and our design was based on those specific makes and models of that equipment rather than needing to design to multiple manufacturers, as often is required from municipal procurement rules in a design-bid-build project. And lastly, we recognized some economies of scale. For Haskell, this meant savings on general contractors (GCs). For Barge, in many cases, this meant a single design was applied to multiple structures or multiple locations.

In Part 2: The team details the construction benefits, contingency and change-order process and measurable success of the progressive design-build project.

Haskell delivers more than $1 billion annually in Architecture, Engineering, Construction (AEC) and Consulting solutions to assure certainty of outcome for complex capital projects worldwide. Haskell is a global, fully integrated, single-source design-build and EPC firm with over 1,800 highly specialized, in-house design, construction and administrative professionals across industrial and commercial markets. With 20+ office locations around the globe, Haskell is a trusted partner for global and emerging clients.

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