Page 16 - Trihydro Sustainability Report

PROJECTS

USE OF NATIVE SOIL FOR LANDFILL COVERS –“WATER BALANCE
COVERS”
FREMONT COUNTY, WY

In an effort to reduce landfill gas and leachate generated at landfills, Trihydro is currently designing four
Water Balance Cover (WBC) systems covering over 150 acres of landfill in Fremont and Albany Counties,
Wyoming. These covers use two to four feet of native soil to trap precipitation and then remove it via
surface evaporation and plant transpiration, as performed by a blend of native grasses planted atop. In
addition to being more sustainable, this method of cover is both safer and more cost-effective than the
traditional method of using synthetic covers, as it degrades and releases hazardous gases that would
otherwise be trapped within the landfill and require additional care.

USE OF PASSIVE SAMPLING DEVICES FOR GROUNDWATER SAMPLING
WINTON, CA

Trihydro is currently managing a site in central California where groundwater has been found to
contain agricultural chemicals, including chlorinated volatile organics. Initially, groundwater impact
was monitored through the use of purge volume sampling, producing 15-60 gallons of waste for each
of the 30 wells at the site. The use of passive sampling devices (Passive Diffusion Bags, or PDBs, and
Hydrasleeves™), which would decrease the waste from 15-60 gallons of waste per well to around 0.5
gallons per well, was investigated during the 3rd quarter sampling event of 2015. The use of passive
sampling methods was used exclusively for the 4th quarter sampling event, and the permanent use
of the passive sampling methods is currently under review by the California Regional Water Quality
Control Board.