Health and sanitation
51 regularly adjusted to account for any losses in chlorine content during storage or handling.
NSF / ANSI Standard 60 certification can help ensure that the quality and effectiveness of water treatment chemicals have been reviewed and found to be acceptable for potable water applications. Some primacy agencies require NSF / ANSI 60 certification. A facility considering application of chlorine gas as the form of chlorine to be used for disinfection would also need to consider potential safety and security concerns. Additional safety procedures will likely be required for personnel training and equipment. Existing OSHA, state or local fire authority regulations may apply and may need to be consulted. Special water system engineering construction standards may also apply for some primacy agencies.
Monitoring frequency and location If a premise plumbing system is a regulated PWS, then the SWTR( USEPA, 1989a) requires that PWSs adding chlorine and using a surface water supply or a ground water supply under the direct influence of surface water monitor for the presence of the residual disinfectant in the distribution system or at the entry point to the distribution system( EP). The disinfectant level must be at least 0.2mg / L at the EP and detectable in at least 95 % of samples collected within the distribution system.
The Stage 1 D / DBPR requires that PWSs that use chlorine maintain a residual disinfectant level of less than 4.0mg / L as a running annual average( USEPA, 1998).
As stated in the SWTR, PWSs that use chlorine are required to monitor for combined or total chlorine residual or heterotrophic plate count( HPC) bacteria in the distribution system at locations that have been approved by the primacy agency( USEPA, 1989a). These parameters could provide operational information to indicate the need for chlorine dose adjustments, system flushing and managing water age within finished water storage facilities.
Maintenance needs Operations and maintenance practices for chlorine disinfection systems include maintenance of an appropriate disinfectant residual, regular system cleaning and flushing, inspections, and water quality monitoring. Newly constructed or rehabilitated piping systems are cleaned and flushed prior to initial disinfection. Routine flushing and water quality monitoring are recommended to assure that adequate disinfectant levels are maintained throughout the premise plumbing system( HSE, 2014).
Since chlorine is recognised as being less effective than other disinfectants at penetrating and controlling established biofilms, chlorination may not be effective if large amounts of scale and sediment are present in the system. These solids are prone to biofilm formation and may need to be removed by cleaning before effective disinfection can be achieved( HSE, 2014). Loret et al.( 2005) recommended flushing dead ends daily with disinfected water and removing premise plumbing fixtures and pipes that are rarely used. PA
“… maintenance of an appropriate disinfectant residual, regular system cleaning and flushing, inspections, and water quality monitoring.”
www. plumbingafrica. co. za April 2017 Volume 23 I Number 2