Chapter 9—Sampling and Flow Measurement of Water

Abstract

A satisfactory sample of water or waste water must meet two basic requirements: It must accurately represent the large or small mass sampled and it must be of adequate size for subsequent laboratory examination. Since industrial water and waste water must be sampled under a great variety of conditions, there is no single method that can be universally applied. The method, location, and time of sampling must be coordinated so the results obtained will serve the purpose for which the sample is intended. Waters or waste waters are not fixed in their compositions but show appreciable changes depending upon their sources, seasonal precipitation, temperatures, wastes, and processes. This chapter discusses variations in composition of industrial water and waste water related to environment and the mechanics of the sampling operation. These should serve as guides in determining the frequency of sampling, the appropriate points, and suitable sampling apparatus. In the study of water as an engineering material, and in the handling, treatment, and disposal of industrial waste water, flow measurement is an essential function demanding applications of many types of flow-measuring devices and equipment to suit specific conditions. This chapter includes a brief summary and description of the classes and categories of flow-measuring devices and equipment to suit specific conditions, the important points to consider in their selection, and the fundamentals of flow measurement.