A visiting expert from the Massachusetts Alternative Septic System Test Center summarized how innovative alternative (IA) septic systems are being used to reduce nitrogen loading and protect drinking‑water and marine embayments, and the Nantucket Board of Health approved several local septic actions after the presentation on July 17.

Expert briefing

George (Massachusetts Alternative Septic System Test Center) told the board that on Cape Cod and the islands IA systems are being deployed primarily to address nitrogen in watersheds and marine embayments. He summarized Title 5 changes that created the nitrogen‑sensitive area (NSA) framework and the Massachusetts Department of Environmental Protection (MassDEP) list of "best available nitrogen technologies" (BANNER). George said boards of health can adopt stricter local regulations than Title 5 and can require IA technologies that meet local discharge limits; monitoring and operator maintenance are key parts of local oversight.

Highlights from the presentation included:
- IA technologies focus on nitrogen removal (typical regulatory benchmark discussed: 19 milligrams per liter as a performance reference and lower concentration targets such as approximately 10–11 mg/L in the most nitrogen‑sensitive areas).
- Towns can require best available nitrogen technology in nitrogen sensitive areas and may condition variances on an operator plan and monitoring to bring a system back into compliance.
- Some technologies perform better than others; local tracking databases (Barnstable County tracking) and the DEP list allow towns to review real‑world performance records.
- Costs for IA systems vary widely; capital costs discussed ranged from roughly $15,000 for lower‑end systems to $50,000–$80,000 or more installed for more complex units; financing and equity programs were noted as policy issues for towns to consider.
- Emerging contaminants (PFAS and other contaminants of emerging concern) are not reliably removed by most on‑site systems; some technologies (e.g., shallow drip, wood‑based systems) can reduce some classes of contaminants more than others, but large‑scale policy changes are required to address PFAS sources.

Board and public Q&A

Board members asked whether the board can require higher performance or specific technologies. George and staff said the board may set discharge limits and require monitoring but cannot mandate a single vendor’s product; they can require a performance standard (for example, the local practice referenced was requiring systems to meet a discharge concentration lower than 19 mg/L in sensitive areas such as Nantucket Harbor or Madaket watershed). The board discussed seasonal use, startup performance, operator responsibilities, monitoring frequency (first year quarterly sampling, then semiannual thereafter in many local practices) and enforcement options if a system fails to meet permit requirements.

Votes at a glance

- Septic loan — 259 Madaket Road: Motion to approve septic loan request for replacement of a failed system for a primary residence; motion seconded and approved. (No vote tally with member names recorded.)

- Local upgrade approval — 24 Arkansas Avenue: Motion to approve local upgrade variances to install a MicroFast IA septic tank in a confined space; abutter support was recorded at the meeting and the board approved the local upgrade application.

- IA variance — Woodland Drive Lot 5: The board approved a variance allowing an IA design with a higher bedroom equivalency than a conventional system, subject to a recorded deed restriction limiting the property to the approved bedroom count and an operational requirement that the installed IA system meet the 19 mg/L performance benchmark (and be monitored per local operation and maintenance requirements — first year quarterly testing, then twice yearly thereafter). The motion was approved by the board; members requested the restrictions be explicit in the recorded documents.

- IA variance — Woodland Drive Lot 6: The board continued the application to the board’s next available meeting (applicant will supply clarified documentation, and the board requested additional information about buildability and permitting sequence for that lot).

- Supplemental meeting: The board voted to schedule a supplemental meeting in August to accelerate policy work during the moratorium on new IA approvals; staff will propose a date and room availability.

Why it matters: IA systems and local variance decisions affect nitrogen loads to Nantucket Harbor, Madaket Harbor and local wellhead protection areas; the board’s use of deed restrictions and monitoring requirements are tools to link relief from conventional rules to compensating environmental protections.

Ending: Board members said they expect continued discussion in the coming weeks to reconcile neighborhood density concerns, legal limits on variances for new construction, and the evolving science on IA system performance and contaminants of emerging concern.