04/29/2020
Community Drinking Water Systems everywhere have experienced a reduction in use and normal flow patterns due to the closure of many facilities with high water demand. This has impacted the water age and in some parts of the transmission and distribution systems stagnation resulting in biofilm growth, potential bacteriological regrowth, biofouling, nitrification and lead and copper leaching. The entire distribution system must be inspected, flushed and measurable disinfectant residual established to the furthest dead-end waterline. This includes but is not limited to; water treatment plants, clear-wells, large transmission mains, reservoirs, storage tanks, standpipes and the distribution pipes to every service point.
The best way to reestablish measurable disinfectant throughout the Community Water System is to flush the system well. Parts of water treatment plants, clear-wells and other large quality storage vessels may need to be removed from service and cleaned more aggressively.
Changes in secondary disinfectant may be considered where appropriate from weaker, less reactive, chloramine to free chlorine during the flushing process. Please ensure all consumers are notified of the daily activates the Community Drinking Water System is taking, as they too are recommissioning their premises water systems, may at the same time. Flushing of the Community Water System should be a well-planned, engineered and executed process. Flushing will cause significant disruption in the distribution system. Sediment, rust, tuberculation and biofilm will pass through into consumer’s businesses and homes, fixtures and appliances.
Everyone in the Community Water System has an important role to play. Make sure to work with the hospitals, hotels, resorts, campuses, factories, food processors… every one of your consumers will be impacted.
Unidirectional Water Main Flushing (UDF) is increasingly used across North America to improve operations, enhance the water system and improve service standards. Water main flushing has long been considered an effective method to remove unwanted tastes, odors or discolorations of the water, and to improve chlorine residual. UDF, a specific type of water main flushing, provides greater cleaning and uses less water than conventional flushing. This article focuses on the implementation of a UDF program, and implementation considerations are discussed for program planning and field activities.
