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