New CE initiative saves money Published April 16, 2009 By Tami Calhoun 92 CES/CEAN FAIRCHILD AIR FORCE BASE, Wash. -- Fairchild's Environmental Restoration team recently initiated the use of a new environmental sampling technique which will produce comparable data to previous methods while lowering costs and producing very little wastewater. A passive diffusion bag sampler was deployed in an environmental monitoring well on the fringe of a large groundwater plume of trichlorolorethylene. The passive diffusion bags are part of a new wave of environmental well sampling techniques. Typical methods for groundwater sampling include instruments like bailers and submersible pumps that agitate the water and create a lot of wastewater requiring costly disposal. New technologies, like the passive diffusion bag samplers, do not disrupt the water column and do not produce significant volumes of wastewater. The way a passive diffusion bag works is allowing certain types of contaminants to pass through the membrane of the bag to the distilled water inside. Over time, the process of diffusion allows the contaminants to pass through the bag's membrane until an equilibrium is reached in which the amount inside the bag is the same as outside the bag which ensures the sample inside is a true representation of the groundwater with which it is in contact. The bag is then pulled to the surface and samples are collected. Fairchild's first passive diffusion bag sampler was deployed at the end of March and will be retrieved and sampled in approximately two weeks by contractor personnel from CH2M Hill.