HEALTH AND SANITATION
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What is supplemental disinfection? Supplemental disinfection refers to any additional treatment, such as that added to reduce legionella, used to supplement or boost the treatment provided by the distributor of the water being received. To address water quality and pathogen control needs, facility operators and owners, after a careful review of the premise plumbing system conditions, may wish to implement a supplemental application of a disinfectant specific to and within the premise plumbing system.
What happens if I add supplemental disinfection in my building? If a decision to add treatment to the premise plumbing system seems likely, facility owners and operators are advised to consult with experts to determine what requirements apply; in addition, to understand any potential water quality issues before making treatment-related decisions.
What should I do before I consider supplemental treatment as a risk management measure? Assuming facility owners and operators have already identified and begun to address underlying premise plumbing system deficiencies that may lead to legionella risks, those considering the addition of a supplemental system are encouraged to familiarise themselves with applicable local regulations( for example building codes, local health codes). Facility owners and operators should also become familiar with the characteristics and needs of their system to help determine the most appropriate action( such as implementing a risk management approach and / or control technologies).
Are there any advantages to supplemental disinfection? Facilities that design, operate, control and monitor supplemental treatment systems are trying to help ensure that a high level of water quality is maintained, thereby improving public health protection. Providing supplemental disinfection may help maintain the high level of water quality throughout the premise plumbing system.
Are there any disadvantages to supplemental disinfection? Operating supplemental water treatment requires the commitment of financial, physical, and staff resources to monitor the treatment process( for example disinfection by-products formation, corrosion), to ensure proper function and legionella control. Other disadvantages may include formation of disinfection by-products, corrosion of piping, or possible degradation of piping materials. An additional disadvantage is that installation of supplemental treatment could lead to a false sense of security. For example, installation of supplemental treatment does not negate the need for facility owners or operators and customers to respond to water supply emergencies( that is,“ boil water” advisories,“ do not consume” notices,“ do not use” notices).
What residual disinfectants and disinfection by-products( DBPs) do I need to monitor? The Stage 1 D / DBPR and Stage 2 D / DBPR established maximum contaminant levels for DBPs and maximum residual disinfectant levels for disinfectant residuals. They also specify the monitoring requirements that regulated PWSs must perform for residual disinfectants and DBPs( type, frequency and location), which will vary depending on the type of system, population served, and type of disinfectants being used.
What qualifications do I need to operate treatments installed at my facility to treat legionella? It depends on a number of factors, including whether your facility is a regulated PWS, the type of water source, and the type of treatment. Certain systems that use chemical disinfectants must be operated by qualified personnel. While the specific requirements may vary, the goal is the same: to ensure that skilled professionals are overseeing the treatment and distribution of safe drinking water. PA www. plumbingafrica. co. za June 2018 Volume 24 I Number 4