Engineers report steady progress, temporary filtration at Gonzales wastewater plant; council hears update

Megan of MSS Engineers, presenting remotely to the Gonzales City Council on Jan. 20, said the industrial wastewater treatment plant is currently averaging an influent flow of about 1.1 million gallons per day, down from roughly 1.2 MGD at the last meeting. She told the council staff focused on influent flow management, effluent quality and aging infrastructure and said the team has been working with significant industrial users to limit flows.

Megan described a set of near-term steps the city has already taken: cleaning and rehabilitating infiltration basins, creating two new basins in flood-prone areas, pumping down Basin D and sending standing water to Treatment Pond No. 2, and setting up a temporary filtration system on site with four clarifiers. She said a contractor is scraping biosolids and that Basin D is expected to be returned to service by Friday. The team is also conducting bioaugmentation dosing in existing ponds, evaluating aeration improvements and assessing sludge-removal alternatives.

On costs, Megan said the city’s capital-improvement program includes available funds that could be redirected toward plant rehabilitation. She said the council previously authorized $1,500,000 under an emergency declaration and that $450,000 of that sum has been spent so far, including the filtration system setup and its first-month rental. Megan also said a dechlorination skid has been ordered and is expected to arrive later in January.

Council members asked about odor complaints on River Road and whether fixing aeration would help. Megan said restoring treatment processes at the head of the plant, improving aeration and removing accumulated sludge would reduce odors and that staff were continuing communications and permit reviews with industrial users under the city’s sewer ordinance. City staff also noted they are preparing discharge permits for major users under the ordinance enacted last year.

Mayor Jose Rios and other council members discussed longer-term options for contingency flows and possible additional land to direct overflow in the event of pond breaches. The mayor reported an adjacent landowner has offered up to 40 acres for city use; staff said they are exploring additional sites, including landfill areas, and that discussions with state water boards and permitting authorities are ongoing.

The presentation closed with staff saying they would continue to refine the filtration and aeration plans, return Basin D to service, pursue the dechlorination installation and bring progress updates to the council.

What happens next: staff will continue basin rehabilitation and bioaugmentation, install the dechlorination skid when it arrives, and refine permit and long-term siting work for overflow protections; the council did not take formal action on the update beyond accepting the report.