P6.3.1.5 Make sure filter Test the water Disinfectant Continue housing is leaving the concentration flushing until Contamination disinfected during filter for signs has not been the of filter cartridge of the reduced to an disinfectant housing when installation, and disinfectant. acceptable concentration changing the flush to waste to reaches an cartridge. Customer remove residual acceptable complaints. disinfectant. level (at least of less than 50% Make sure the giardiasis or of its MAV3). person replacing the cartridges Train staff if in the the correct way to necessary. community do it to avoid associated with contamination. periods of poor water quality. 3 The consequences of the event, and therefore the level of risk, will be influenced by the quality of the source water. Preventive measures Checking preventive measures Corrective action Causes What to check Signs that action is needed Event: FILTER NOT REMOVING PARTICLES DOWN TO 2-3 µm IN SIZE cont’d P6.3.1.6 Keep flow rate less Flow rate. Cloudiness in Reduce flow to than design the water within Flow too high Particle maximum. following specifications. for cartridge counting or filtration. design. microscopic particle Filter unable to analysis test remove more results, or the than 99.9% of results of any particles test greater than 2-3 approved by µm in size the Ministry of entering it. Health. Customer complaints. Cases of giardiasis or in the community associated with periods of poor water quality. Flow too high. Event: FILTER NOT REMOVING TARGET CHEMICAL CONTAMINANTS Possible hazards: Health-significant chemical determinands. Level of risk: Low3
P6.3.1.5 Contamination of filter housing when changing the cartridge. Make sure filter housing is disinfected during cartridge installation, and flush to waste to remove residual disinfectant. Make sure the person replacing the cartridges the correct way to do it to avoid contamination. Test the water leaving the filter for signs of the disinfectant. Disinfectant concentration has not been reduced to an acceptable Customer complaints. of giardiasis or in the community associated with periods of poor water quality. Continue flushing until the disinfectant concentration reaches an acceptable level (at least less than 50% of its MAV3). Train staff if necessary. 3 The consequences of the event, and therefore the level of risk, will be influenced by the quality of the source water. Causes Preventive measures Checking preventive measures Corrective action What to check Signs that action is needed Event: FILTER NOT REMOVING PARTICLES DOWN TO 2-3 µm IN SIZE cont’d P6.3.1.6 Flow too high for cartridge design. Keep flow rate less than design maximum. Flow rate. Particle counting or microscopic particle analysis test results, or the results of any test approved by the Ministry of Health. Cloudiness in the water following filtration. Filter unable to remove more than 99.9% of particles greater than 2-3 µm in size entering it. Customer complaints. Cases of giardiasis or in the community associated with periods of poor water quality. Flow too high. Reduce flow to within specifications. Event: FILTER NOT REMOVING TARGET CHEMICAL CONTAMINANTS Possible hazards: Health-significant chemical determinands. Level of risk: Low3