Evaluation of a sampler for liquid effluents

Abstract

A design of automatic sampler for liquid effluent streams is described, which is based on the use of a rapidly circulating pumped stream of the liquid effluent. This stream passes through an interceptor vessel from which sub-samples may be taken iso-kinetically to provide a variety of sample types (e.g. snap, composite, flow-related). This interceptor may be conveniently located and may also be used to hold monitoring probes (pH, ion selective electrodes) which will provide continuous information on the composition of the effluent stream. This sampler system has been evaluated using simulated liquid effluents, chosen to represent cases in which it is difficult to acquire a truly representative sample. The cases chosen were: 1. (a) water containing up to 10,000 mg 1 −1 of finely divided inorganic solid; 2. (b) water containing 2000 mg l −1 of sewage solids 3. (c) water containing dissolved, volatile organic solutes; 4. (d) water containing dispersed oil. In all cases it proved practical to obtain samples which were representative in composition of the liquid being tested; comparison in all cases was with snap samples taken simultaneously from appropriate points in the loop system. The sampler appears to be generally suitable for use with most types of liquid effluents. The several components of the sampler should be constructed of materials which are inert to the effluent.