Bedford County advisory committee reviews decentralized "step" wastewater systems and agrees to draft local standards

The Bedford County Wastewater Advisory Committee on March 12 heard detailed presentations about decentralized "step" wastewater systems — technologies that use on-site pre-treatment, pressurized collection lines, recirculating-media treatment trains and drip-field effluent dispersal — and agreed to develop local rules for the planning commission to review.

Mark Lee, a consultant who helped develop early step-system guidance, described the systems’ four components and said they can allow higher lot yield where soils are suitable. "We call them step systems because of the septic tank and it's got an effluent pump in there," Lee said, explaining that designers begin by mapping usable soils with NRCS surveys and a registered soil scientist to size drip fields and determine lot yield.

The presenters emphasized conservative design assumptions. Lee and Matt Nicks of Edge Wastewater said residential design flow is set at 300 gallons per day (gpd) per lot, a number they called conservative compared with measured community averages. "Historically you're looking at 165 to 175 gallons a day of flow on average across a community," Lee said, a point Matt Nicks reiterated when discussing rental housing: "We're doing a rental community ... we're going to increase that" to allow for heavier use.

Technical trade-offs and operating costs were a major focus. Lee described Bioclear recirculating-media units and control buildings with UV disinfection and filters. He estimated energy use at roughly 750 kilowatt-hours per month per Bioclear unit and about $175 per train per month at $0.10/kWh. For a 200-house system (about 60,000 gpd), presenters estimated a Bioclear-based installation in the $1.9 million to $2.3 million range; they said Ecopod-style concrete systems cost substantially more.

Design details discussed included:

- Soils mapping and drip dispersal: tubes buried about 7–8 inches, emitters spaced typically 2–5 feet, and a need for high-intensity soils mapping and test pits before siting drip fields. Lee said some counties require 100-foot grids for mapping and others 50-foot grids.

- Loading rates and reserve area: while state guidance cited by presenters (TDEC/TAC references in the presentation) allows up to 0.25 gpd per square foot for well-drained soils, Lee said his company uses 0.20 gpd/ft² for well-drained and 0.10 gpd/ft² for moderately well-drained soils. Presenters noted most projects use a 50% reserve area, though some local proposals seek 100% reserves.

- Storage and resilience: designers account for storage at the septic vaults (1,500–1,800 gallons typical), pipe storage and one day of storage at the treatment plant. Presenters estimated multiple days of storage overall and described options for extra storage ponds or temporary generators in extreme outages.

- Operations and governance: presenters outlined three models — developer-led private utilities that hire operators, planning-commission-regulated installs with stronger local oversight, or utility-district ownership where the district owns plants and contracts operations. Nicks said private operators typically bill homeowners, estimating an average monthly sewer bill around $55 under a private operation model.

Construction and maintenance details were presented by installer Eddie Price, who showed state-approved plans, construction photos and described site constraints in Bedford County (rock, groundwater and occasional blasting). He recommended fencing treatment areas and designing for maintenance access: "chain link fence around the area ... just keeps anybody from messing with that system," Price said.

Committee members pressed presenters on durability and failure causes. Lee said failures are often linked to construction errors — for example, contractors removing or moving good soils before installation — rather than to the step technology itself. He recommended careful soils mapping and on-site inspection during construction.

Next steps and local policy

Committee members asked the presenters to provide a concise list of decision points and recommended standards (what the county can set locally versus what is set by state agencies). The advisory committee agreed to use the materials from CUD and the presenters as a starting point and to draft a recommended set of rules and regulations to submit to the planning commission for public hearing. The committee set a next meeting for April 9 to review a proposed checklist and draft language.

Votes at a glance

- Agenda approved by voice vote (motion carried). - Minutes of the Feb. 12 meeting approved by voice vote (motion carried). - Meeting adjourned after a motion to adjourn (motion carried).

What to watch

The committee requested: a short decision checklist from presenters (which components the county must decide: loading-rate defaults, reserve-area policy, acceptable technologies or performance standards, inspection/approval roles, bonding/performance guarantees), sample regulatory language, and comparative cost estimates for enforcement and escrow arrangements. Those materials will shape the planning commission recommendation and any public outreach the county pursues.