County approves leachate reverse-osmosis pilots and temporary landfill-gas O&M contract

The Board of County Commissioners approved two related solid-waste items on June 2: a plan to pilot reverse‑osmosis (RO) pre-treatment for landfill leachate and a short-term purchase order to maintain landfill gas operations while a formal solicitation is prepared.

Iman Schimetha, managing director of the Solid Waste Disposal District, explained that the county’s Heartland evaporator treats leachate by evaporation but has limited capacity (roughly 30,000 gallons per day) and a 500,000‑gallon storage tank. During rainy seasons and when new cells generate high volumes of leachate, the evaporator can be overwhelmed and staff must divert surplus to the wastewater plant.

To reduce diversions, the district engaged Geocentech to evaluate pretreatment technologies and recommended testing two mobile RO systems in sequence with the evaporator. Geocentech and staff recommended two three‑month pilots (one from Heartland/Hartland and one from Sustainable Landfill Solutions, SLS) with on‑site, modular units sized around 25,000 gallons per day. The RO units would produce about 70% clean water (diverted to the wastewater plant) and 30% concentrate that the evaporator would then process.

Schimetha said staff evaluated cost and performance; presented cost-per-gallon estimates of roughly $0.16–$0.18 per gallon, and cited a combined six‑month pilot cost of about $794,610. Staff recommended waiving formal bidding and authorizing the purchasing manager to issue three‑month purchase orders to both vendors, with Geocentech to evaluate results and return to the board with findings and recommendations.

Commissioners asked about mobilization timelines, membrane lifespan, sampling frequency and the plan to obtain updated laboratory data. Staff said they expect mobilization within three to four weeks after regulatory notifications and that the pilot will include baseline and periodic sampling to assess raw leachate, post-RO quality, and any impacts on the evaporator.

Separately, the board approved a temporary procurement to maintain landfill gas operations and maintenance (O&M) until a competitive RFP is issued. Republic Services had been subcontracting Integrity Environmental Solutions to perform O&M; staff recommended issuing a six‑month purchase order to Integrity not to exceed about $242,000 to preserve continuity and maximize gas recovery for the county’s renewable natural gas project. That motion carried unanimously (4–0) with Commissioner Susan Adams absent.

What happens next: Geocentech will monitor both RO pilots, perform laboratory sampling, and report back to the board with data and recommendations; staff will issue the short-term PO for O&M and proceed with a formal RFP for longer-term services.