Free Up Land by Replacing Multiple Modular Plants With One Large Concentric Circle Treatment Plant
It can make sense when factors such as available space and predicted growth come together
As communities grow, modular wastewater treatment plants often expand in phases, with one unit being added at a time. This can eventually result in a large, sprawling plant that takes up valuable space. When the size of a plant’s footprint starts to outweigh its function, upgrading to a single, larger treatment plant can reclaim valuable land, simplify operations, and support long-term planning.
Today, many Texas utilities and developers are consolidating multiple small modular units into high-capacity concentric circle systems — freeing up acreage for future amenities, additional housing, or revenue-generating uses while improving treatment performance.
Modular wastewater treatment plants offer a quick, cost-efficient approach for fast-growing communities to get the services they need. This approach allows communities to start with a small, affordable system and expand their treatment capacity by adding additional modules as the demand increases.
But, when clusters of modular plants take up a significant area of land that could be put to better use, it may limit expansion. Consolidation offers a strategic solution. Modern large-diameter clarifiers now make it possible to replace multiple small units with one high-capacity system.
Why Consolidation Is Growing
Texas is one of the fastest-growing states in the country, with the population projected to increase by 8.6 million in the next 25 years. With the population increasing at lightning speed, some communities are growing faster than legacy modular systems can scale. To meet the growing demand for housing, developers and utilities are continually striving to maximize land use without compromising treatment efficiency.
Larger concentric circle plants offer a viable solution for consolidating multiple modular systems into one larger unit that can accommodate a higher throughput within a smaller overall footprint. New technology, such as WAWCON pier-supported internals, allows diameter options to be expanded beyond traditional limits, enabling AUC Group to build large-scale wastewater treatment plants with clarifiers exceeding 57 feet in diameter.
Land Recovery: The Most Valuable Benefit
A single large concentric circle plant can replace several modular tanks, reducing the footprint of the overall plant and opening valuable land for new development.
One of the strongest drivers behind consolidation is land recovery—often the most valuable asset a developer controls. Replacing several modular tanks with one larger concentric circle plant can free up a significant amount of space. This recovered land is now available for other uses, including:
- New housing lots
- Amenities such as parks, playgrounds, community centers, and trails
- Future utility expansions or ancillary services
- Revenue-generating uses
For example, a subdivision that consolidates treatment infrastructure by replacing several modular tanks with one large concentric circle plant could gain five to 10 or more lots, which could generate a significant source of revenue for the developer in the form of rentals or sales.
Operational Advantages of a Large Concentric Circle Plant
Besides freeing up valuable land for other uses, larger concentric circle plants offer several other key benefits:
- Simpler operations: With only one basin instead of multiple units to manage and maintain, O&M is simplified, with fewer mechanical assemblies and therefore, fewer points of failure. A single treatment basin also streamlines sludge collection and scum handling.
- More consistent treatment: Larger clarifiers provide steadier hydraulic conditions, handle higher peak flows, and improve solids settling—resulting in more reliable effluent quality as communities grow.
- Lower long-term costs: AUC’s large clarifiers are supported by WAWCON internals, which have a proven track record for their durability and long-term performance. As a result, their lifecycle costs are lower than for multiple small packages. Their enhanced reliability reduces staff burden — less routine maintenance is required, which also reduces downtime and maintenance costs.
When Consolidation Makes Sense
For developers and utilities trying to decide whether to expand or replace an existing modular system, some key factors may indicate it’s time to consider consolidation as a strategic option. They include:
- Limited space: The site cannot accommodate additional modular units needed for growth, or the existing basin is aging and due for replacement.
- High O&M burden: Maintaining multiple small units strains staff, budgets, and reliability.
- Capacity pressures: Most modular configurations top out around 0.5–1.5 MGD, which may make a single large clarifier more efficient for long-term service.
How Modern Clarifier Design Enables This Shift
Larger clarifiers of more than 57 feet in diameter are now feasible due to pier-supported internals. They can even reach more than 80 feet. AUC prefabricates these internals in-house, accelerating production timelines, shortening timelines, and streamlining installation, allowing us to deliver in 12 weeks rather than 30-plus weeks needed for most competitors.
Once in place, the larger clarifiers integrate seamlessly into existing influent channels, RAS/WAS loops, and effluent structures. Because they are suitable for use in either steel or concrete basins, they offer a practical solution for retrofitting an existing basin. The result is a clarifier that expands treatment capacity and improves efficiency, while minimizing construction disruption and engineering complexity.
What to Consider Before Consolidating
Before consolidating treatment into one, larger clarifier, it helps to step back and take a clear-eyed look at the full picture. The first step is understanding current hydraulic loads and anticipating what those flows will look like five, 10, or even 20 years from now. A clarifier sized with only current needs in mind can quickly become insufficient.
Once current and future capacity needs have been thoroughly assessed, the physical parameters of the site — including basin condition, structural integrity, and available land — must be evaluated to determine whether consolidation is practical. An older basin with compromised concrete may not justify rehabilitation costs, while a space-constrained site may limit the diameter of any new structure.
It’s also important to consider how the new clarifier will integrate with existing influent channels and downstream treatment units.
One of the biggest decisions faced in any consolidation project is whether to build a new basin from the ground up or retrofit an existing one. New basins offer design freedom but require more space, while retrofits can save money and simplify permitting if the underlying structure is sound.
Regardless of the option, it’s important to plan for long-term growth. The most successful projects are the ones that leave room to expand, add new process units, or incorporate advanced treatment technologies later on.
A Smarter Way to Maximize Land and Treatment Performance
Consolidating multiple modular packages into a single, large concentric circle plant can reclaim valuable land, reduce operational complexity, and deliver more reliable treatment for fast-growing communities. For many Texas utilities and developers, it’s a practical step toward long-term planning and smarter infrastructure investment.
Discover how much land and operational efficiency you could gain by consolidating. Contact AUC for a clarifier sizing review or project consultation.
