Consultants recommend MBBR to tackle Beaumont wastewater ammonia limits; council told to prepare for permit negotiations

Consultants who led Beaumont’s wastewater treatment plant master plan told the City Council on May 5 that the city faces looming ammonia discharge limits and should invest in a moving bed biofilm reactor (MBBR) to meet them.

John D’Antoni of Black & Veatch, introduced by city staff, and Jeff Beaver of SPI/Schomburg & Polk described a facility built in 1952 that currently treats roughly 16–20 million gallons per day and relies in part on a constructed wetland, the Cattail Marsh, installed in 1993 for ammonia removal. The consultants said the wetlands are valuable but overloaded for more stringent permit limits coming in future phases.

“The wetlands can only do so much,” D’Antoni said, noting the city’s current permit limit of 7 milligrams per liter and a pending earlier permit phase that would lower the limit to 3 milligrams per liter during critical months. He said the plant “would have been out of compliance every month” under the stricter number using 2024 data and recommended a near‑term engineering solution to avoid enforcement risk.

After evaluating six technical alternatives — including conversion to activated sludge, deepening trickling filters, membrane systems (MABR), moving bed bioreactors (MBBR), algal systems and submerged attached growth reactors — the consultant team recommended the MBBR as the best balance of capital and operating cost, reliability and operational simplicity. “We felt the best alternative … was the MBBR,” D’Antoni said, adding that a 20–24 MGD MBBR was among the more practical options.

Consultants also presented a set of prioritized maintenance and rehabilitation projects across the plant’s 14 asset areas: lift stations, clarifiers, aeration ponds, grit systems, pumps and transformers, lining and coatings, sludge digester and disinfection basin repairs, and sediment removal in the transfer canal to Cattail Marsh. Jeff Beaver described an aerial drone survey of the Cattail Marsh and proposed scheduled cell maintenance (approximately one or two cells a year) to restore the wetland’s emergent vegetation and preserve its ammonia‑removal function.

The team estimated the capital cost for a typical MBBR installation at about $20 million to $25 million for the capacity range discussed, and described a broader multiyear list of projects that would be phased through the city’s community investment program. Staff noted funds for some items are already in the CIP; consultants recommended early engagement with the Texas Commission on Environmental Quality (TCEQ) ahead of the next permit renewal cycle, which staff said will begin in 2028. “I would wholeheartedly recommend that you have that dialogue and open those discussions,” D’Antoni told council members.

Council members asked whether ammonia limits are fixed and what enforcement looks like. D’Antoni said the pending limits in the permit are not being enforced today but are included as future limits; repeated violations could lead first to warnings then fines and, ultimately, an administrative consent order. “If you consistently miss those permits, you wind up in an administrative corrective order,” he said.

The presentation and question period closed with staff offering copies of the full master plan and five supporting technical memoranda, and a council motion was not required at the meeting. The presentation will inform the city’s CIP prioritization and budgeting work, and staff said they will return with procurement and funding options as projects are scoped. The council also discussed possible approaches including shifting the discharge point or augmenting the wetlands, but consultants emphasized that the MBBR was the most proven, lower‑risk technical option in the near term.

Next steps: staff will include recommended projects in the upcoming CIP and begin the permit and funding conversations with TCEQ and council in advance of the 2028 renewal process.