The Suction Side Sample Catcher in Ground Water Quality Sampling

A suction side sample collector (SSSC) is a contrivance installed hydraulically ahead of the intake port of a pumping device. This paper describes construction and operational details of SSSCs fitted to a submersible pump with packer for use in a 6-inch cased borehole, an air lift pump with packer for use in a 1-inch or 2.5-inch cased borehole, a bladder pump for use in a casing of 2-inch or greater diameter, and a jet pump with packer for use in a 2-inch cased borehole.
Each form of SSSC has been thoroughly tested in ground water quality sampling for volatile organic chemicals. Comparative data for samples collected with the SSSCs and conventional sample collecting gear are presented. The SSSC is demonstrated to be superior to other methods of collecting volatile organic chemical samples owing to its freedom from contamination by the pump delivery line and to its mode of collecting the sample from a position in the well remote from disturbance by the pumping technique.
SSSCs are conveniently decontaminated, easily transported, and can be used to deliver samples to the laboratory while still at formation pressure. The air-lift pumps, described in this paper for use with SSSCs in 1- and 2.5-inch casings, have pumping capacities greater than obtained by other methods that can operate in these small casings. Discharge rates of up to 2 gpm are routinely achieved with the 1-inch model and higher rates are common With the 2.5-inch model. The use of packers with these pumps reduces the time needed to replace the water in the casing with fresh water from the formation.