Standards Development

Scope

Continuous monitoring enables to measure water quality parameters that are essential for water monitoring to be tracked over sufficiently short time intervals to be able to conduct a detailed study of temporal variability. It offers the particular advantage of acquiring representative data of variations in water, compared with spot sampling campaigns conducted at fixed intervals which can miss significant events such as a concentration peak during a flood or rainfall episode.

Moreover, in the event of pollution due to industrial accidents or transport on inland waterways for example, it is vital to be able to detect these events as early as possible and react rapidly to limit their impacts on the environment and thereby indirectly protect the drinking water resource.

Consequently, the choice of having recourse to continuous measuring devices is directly linked to the advantages of obtaining a rapid measurement (a few seconds to a few minutes) at short time intervals (from a few seconds to a few hours) and in most cases in real time. Furthermore, it is possible to use the resulting measurements to automatically trigger actions, such as taking a sample for further analysis and/or stopping pumping of the drinking water resource.

To set up a continuous measurement system, it is recommended to follow a procedure that comprises 5 main steps:

1) defining the purposes of the measurements and the associated data quality requirements;

2) selecting appropriate measuring devices;

3) installing the measuring devices and setting their parameters;

4) preliminary validation under real conditions: performance verification and maintenance optimisation;

5) operational implementation.

This document describes the good practices and gives recommendations for each of the abovementioned steps.

This document applies to continuous measuring devices for monitoring physical-chemical parameters in different types of water, including continental fresh waters, marine waters, drinking water and urban and industrial wastewaters, as well as the monitoring of industrial processes.

The continuous measuring devices include single-parameter or multi-parameter in situ probes, sensors and on-line analysers.

Purpose

This new project was developed to answer a need identified in the strategic position paper on “Standardization needs in continuous water quality monitoring” written by CEN SABE (N333) :

“In order to ensure the reliability of the data generated by monitoring devices (MDs), quality assurance and control systems need to be implemented to demonstrate the fitness-for-purpose of the MDs prior to installation and that their performance levels can be maintained in the long run.”