This part of ISO 5667 contains details on the sampling of domestic and industrial waste water, i.e. the design of sampling programmes and techniques for the collection of samples. It covers waste water in all its forms, i.e. industrial waste water, and crude and treated domestic waste water.
Sampling of accidental spillages is not included, although the methods described in certain cases may also be applicable to spillages.
A sampling programme may be based on many different objectives. Some of the more common objectives are:
- to determine the concentration of pollutants in a waste-water stream;
- to determine the load of pollutants carried by a waste-water stream;
- to provide data for the operation of a waste-water treatment plant;
- to test whether given discharge concentration limits are kept;
- to test whether given discharge load limits are kept;
- to provide data for the levy upon discharge of waste water.
When designing a waste-water sampling programme, it is essential for the objective of the study to be kept in mind, so that the information gained from the study corresponds closely to the information required.
Generally, the objectives of sampling are quality control or quality characterization, as described in 1.1.1 and 1.1.2.
1.1.1 Quality characterization
Quality characterization aims at determining the concentration or load of pollutants in a waste-water stream, generally during an extended period of time, for example, to monitor compliance with a standard, to determine trends, to provide data on unit process efficiency or to provide loading data for planning and/or design purposes.
1.1.2 Quality control
The objective of quality control may be one of the following:
a) to provide data for either short-term or long-term control of waste-water treatment plant operation (e.g. control of biomass growth in activated sludge units, control of anaerobic digestion processes, control of industrial effluent treatment plants);
b) to provide data for waste-water treatment plant protection (e.g. to provide domestic waste-water plants with protection against deleterious effects from industrial effluents, to identify the sources of undesirable industrial effluent residues);
c) to provide data for pollution control (e.g. controlling disposal operations to land, sea or water courses).