8.6.2 Managing risks
A complete water quality management program needs to recognise any potential risks from use of drinking water treatment chemicals and include strategies to manage them appropriately. These risks should be minimised by the implementation of a quality assurance system for the management of production, supply, delivery and use of water treatment chemicals.
The first step in managing the risk associated with the use of drinking water treatment chemicals is to ensure that the chemicals supplied meet a minimum standard, as established by the relevant state or territory regulatory agency. For example, water authorities may formally specify the strength of active ingredient and acceptable contaminant levels in each drinking water treatment chemical (see Section 8.6.3). However, this in itself will not adequately control the risk. The contractual requirement should be supported by batch-testing data provided by the supplier from an independent NATA (National Association of Testing Authorities) accredited laboratory, and random testing carried out by the water authority itself. Chemicals should not be accepted for delivery unless a batch analysis certificate has been obtained and checked by the water authority.
Formal accreditation of the manufacturing facility by an independent accreditation agency (e.g. the International Organization for Standardization (ISO) or NSF International) provides a further level of risk management. Such accreditation should include random site visits to the manufacturing facilities by the relevant regulatory agency and, if warranted, the water authority.
Chemical suppliers should be evaluated and selected on their ability to supply products in accordance with required specifications. Documented procedures for the control of chemicals, including purchasing, verification, handling, storage and maintenance, should be established to assure the quality of the chemical at the point of application (see Section 3.10.1). Responsibilities for testing and quality assurance of chemicals (supplier, purchaser or both) should be clearly defined in purchase contracts.
An important step in a quality assurance system for chemical addition to drinking water is to ensure that the required chemical is of the specified quality, and specified strength, and is delivered into the correct storage vessel, at the correct site at the correct time. This is necessary to:
ensure that the correct chemical at the required concentration is used in drinking water treatment;
ensure that cross-contamination of storages does not occur;
ensure inappropriate and unsafe mixing of chemicals does not occur;
help to ensure the health and wellbeing of staff and contractors during the delivery and dosing process.
Broadly, the objective of the water treatment chemical quality assurance system is to manage all the factors associated with the specification, contract management, supply, storage, use and handling of water treatment chemicals that could have an adverse impact on the health and wellbeing of staff, contractors and consumers. Box 8.1 outlines the components that make up an effective quality assurance system for drinking water treatment chemicals.
Desirable components of a quality assurance system
A quality assurance system for chemicals used in the production of drinking water might include:
selection of chemical suppliers based on their ability to meet specified requirements for supply and delivery, monitoring and analytical testing of contaminants;
selection of suppliers who have a quality management system that is certified by an independent accreditation agency;
an appropriate monitoring program to ensure that chemicals comply with specifications;
an audit process for the supplier’s manufacturing, storage and delivery processes;
a formal checklist for the dispatch and delivery process;
a delivery driver induction system for each site, with each driver inducted onto each site, together with appropriate record-keeping procedures;
the provision of details of the delivery site (site photographs may be useful);
an identity check directly linking the delivery driver to the chemical company;
the clear identification and labelling of chemical storage vessels, filling points and delivery pipe work at all sites (locks on filling points are desirable);
a requirement that chemicals should only be delivered when an appropriate water authority staff member is present to check documentation, including batch analysis certification, and to ensure unloading to the correct storage vessel;
a standard operating procedure for the delivery and receipt of chemicals at each delivery site, including a documented acceptance criteria system to assist site operations staff in assessing whether to accept or reject the delivery of a chemical;
a gross visual check of the chemical and, where appropriate, simple physical testing by the water authority representative at the delivery site before unloading;
a check by both parties that the delivery vessel is being connected to the correct storage vessel;
a check that appropriate personal protective equipment is being worn, and that relevant health and safety requirements are being addressed;
appropriate recording and storage of relevant documentation;
a system to ensure that any spillage associated with the delivery process is contained and does not escape to the environment;
an emergency procedure in the event of possible systems failure or human error.
The combination of a chemical quality assurance system and a delivery and storage quality assurance system such as those outlined in Box 8.1 can significantly reduce risks to all stakeholders. The combined system should include formal quality audits (see Section 3.11).
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