Florida committee hears on-site wastewater technologies that can remove up to 85% of nitrogen

Roxanne Groover, executive director of the Florida On-site Wastewater Association, told the Senate Committee on Environment and Natural Resources on March 5 that advanced on-site wastewater systems can reduce nitrogen in effluent “at a minimum of 50% reduction all the way up to an 85% reduction, at the end of pipe.”

Groover told committee members the presentation focused on advanced-treatment systems rather than conventional septic tanks and outlined three regulatory and technical pathways used in Florida: NSF/ANSI-certified systems (commonly referred to in the presentation as NSF 245 or NSF 350 devices), performance‑based treatment systems allowed through state evaluation or the department—s ‘‘innovative’’ process, and the in-ground nitrogen-reducing biofilter (INRB).

Why this matters: On-site systems treat about one‑third of wastewater in Florida, Groover said, but those systems receive “less than 1% of the funding that—s available.” Committee members pressed on where advanced systems are required, how they are permitted and maintained, and how grant programs are being used to accelerate upgrades in priority watersheds.

Groover described technology classes and expected nitrogen removal ranges. Suspended‑aeration, submerged fixed‑film, membrane/media filters and sequencing batch reactors were shown as on-site versions of municipal technologies; Groover said those approaches produce roughly 50%–85% total nitrogen reduction in the tank depending on configuration and manufacturer testing. She said NSF/ANSI standards and state testing determine the certified performance level and that Florida requires a licensed professional engineer to certify tank integrity for many products placed in the ground.

Groover explained that some NSF‑certified systems meet only the baseline 50% reduction while other manufacturers add features (recirculation, anoxic zones, proprietary carbon sources or submerged media) and then retest to demonstrate higher removal. She said the state—s springs protection requirements impose a 65% effective total nitrogen standard for technologies used in priority springs areas; systems with lower tested end‑of‑pipe removal must rely on additional soil treatment or separation to meet the springs standard.

On permitting and maintenance, Groover said many advanced systems require an operating permit and an identified maintenance entity; residential systems are typically inspected twice a year and commercial systems four times a year. The INRB passive biofilter, she said, was allowed beginning in 2018 as a nonproprietary passive option (initial unlined designs did not require an engineer—s design or an operating permit; later lined designs required a PE and registration). Groover said INRBs carry a presumed 65% nitrogen reduction in code and that title notice on the property is required to inform future owners.

Committee members asked about phosphorus and PFAS. Senator Joe Harrell asked, “Do any of these systems work for phosphorus? And how about PFAS?” Groover replied that phosphorus‑removal technologies exist and that PFAS is an emerging issue; she said manufacturers and the NSF joint committee are discussing PFAS testing and that ongoing standard‑setting work will address new contaminants as they arise.

Groover also reviewed grant programs used to fund upgrades in targeted watersheds. She said Volusia County—s program for a spring area began with a $10,000 per‑system grant and has sought to increase that to $15,000 to help homeowners pay the incremental cost of an upgrade; Hernando County—s program, she said, “offers up to $7,500 per installation” and has completed hundreds of installs (transcript references indicate 436 of 466 installs were completed). Groover highlighted Brevard County—s Save Our Lagoon program, noting the program—s on‑site upgrade budget was reported as $29,000,000 and that on‑site upgrades there were estimated to reduce about 38,000 pounds of nitrogen per year; she said 287 homeowner upgrades had been completed in that program phase as reported to the association.

Groover closed by reiterating the scale of on‑site treatment in Florida—s wastewater portfolio and the limited funding available for upgrades. She encouraged coordinated local efforts, use of performance‑based allowances where appropriate (for example, smaller drain fields or higher allowable flows for higher‑performing systems), and additional incentives or research to better document passive systems— field performance.

Committee context and next steps: Senators and the presenter noted that recent statutory changes and springs‑area remediation plans will drive more local OSTDS remediation plans this year, and that July is an expected timing milestone for new remediation plans entering local permitting programs. Groover encouraged lawmakers and local officials to consider funding mechanisms and incentives to support larger‑scale on‑site upgrade programs rather than relying solely on sewer extensions.