Lahontan board adopts revised waste discharge requirements for Mojave Rosamond landfill

The Lahontan Regional Water Quality Control Board voted to adopt revised waste discharge requirements and a corrective action program for the Mojave Rosamond Recycling and Sanitary Landfill in Kern County, including conditions for the proposed Phase 2a/2b/2c expansion and an engineered alternative liner system.

Board members closed a public hearing after a staff presentation outlining site history, contaminant plumes and the proposed safeguards. "Water board staff recommend the adoption of the revised waste discharge requirements and corrective action at the Mojave Rosamond Recycling And Sanitary Landfill," said Tiara Crusius, an engineering geologist in the Victorville office, summarizing staff's recommendation and the proposed monitoring updates.

The staff presentation described a long record of groundwater monitoring that identified volatile organic compounds primarily from landfill-gas migration. Crusius said the maximum historic PCE detection was 0.7 micrograms per liter and the highest Freon 12 detection was 2 micrograms per liter, with impacted groundwater mapped roughly 500 feet downgradient of the waste management unit. Staff proposed monitored natural attenuation, drainage controls and diversion programs as part of a corrective action program that has been in place since 2012.

The Phase 2a/2b/2c design differs from the unlined Phase 1: staff described a composite engineered liner system, a leachate collection and removal design constructed in accordance with California Code of Regulations, title 27, and a drainage geocomposite as an engineered alternative to prescriptive drainage gravel. Crusius also noted Phase 2 includes a pan lysimeter at the sump to monitor for leakage.

Board members asked staff to clarify the intended beneficial uses protective endpoints and the expansion footprint. Staff identified groundwater beneficial uses including new agricultural supply, industrial service and freshwater replenishment and said the combined Phase 1 and Phase 2 waste footprint would increase from roughly 27 acres to about 253 acres; the Phase 2 waste footprint alone was listed in staff materials as increasing from 40 acres to 82.9 acres.

A motion to adopt staff's recommendation carried, with board members recording affirmative votes. The order establishes monitoring and construction requirements for the expansion and a corrective action program to address the documented VOC release; the final board order will include the conditions described in the staff presentation and the monitoring and reporting program updates.

The board closed the item and moved on to its executive officer report.