Drinking-water quality management procedures normally consist of four main stages:
- Stage 1: Familiarisation with water supply scheme
- Stage 2: Preliminary water quality investigation
- Stage 3: Definition of operations, management team and responsibilities
- Stage 4: Implementation of the monitoring process
These stages are described in more detail below.
Stage 1: Familiarisation with water supply scheme
Initially all the basic information relating to the water supply scheme is collected. This includes information relating to the raw water sources, vulnerability of sources to pollution, water and wastewater treatment requirements and existing treatment procedures, the water distribution network, water quality records (if any) and the current water quality management procedures (if any).
Stage 2: Preliminary water quality investigation
In the preliminary water quality investigation, particular attention is paid to potentially problematic issues and areas where historical data is insufficient. Samples are collected from source through the distribution network, and can also include evaluation of final effluent discharges to the environment. This study highlights the major water quality problems in the water supply scheme.
Stage 3: Definition of operations, management team and responsibilities
In this stage, the responsibilities of the municipal team and any external consultants/contractors must be clearly outlined. The focus of these interactions is on skills training, capacity building, technical support, planning and facilitation of implementation of the water quality management plan.
Stage 4: Implementation of the monitoring process
The implementation of the monitoring process should consider:
Design of monthly sampling programme
Based on the findings of the preliminary stages of the water quality management procedures, a water quality monitoring programme is designed. The monitoring programme ensures that water quality is monitored from source to the end user. This enables easy identification of problematic issues relating to the treatment and supply of drinking water. In addition, the water quality monitoring and management programme is flexible in order to address unexpected issues.
Sample sites - Typical sampling sites included in water quality monitoring programmes include raw water sources, water and wastewater treatment works, reservoirs, extremities of the distribution network, sites where previous sampling revealed problems and random sites, such as multi-occupancy buildings (e.g. hospitals, schools, etc.) NOTE: The number of samples collected varies with the size of the community.
Water quality determinants - Based on knowledge of raw water characteristics and water treatment operations, microbiological, physical and chemical water quality parameters are determined.
Sampling, analysis and data review - Trained staff should carry out sample collection, handling, transport, storage and processing in accordance with standard sampling techniques. All analyses should be conducted using standard laboratory techniques (preferably in SANAS accredited Analytical Laboratories). The analytical results are then compared to the appropriate water quality standards/guidelines.
Iterative management of water quality - An iterative management procedure is followed depending on results from the information review. Where no failures occur, information is used to optimise treatment procedures. Where failures occur, a process of investigation and trouble-shooting takes place with subsequent implementation of temporary and medium-term solutions.
Summary report - A summary report displaying water quality, discussion thereof and recommended actions is produced. This report serves as an important tool for on-going management of the water supply network. The report is structured in such a way to bring attention to problematic areas, such that the responsible parties are immediately aware of potential problems.