Basic Water Main Flushing in a Distribution System
Instead of water flowing out of fire hydrants and running to waste, the NO-DES process utilizes a trailer mounted pumping, filtering and re-chlorinating system which circulates the water within the water distribution system. The NO-DES unit is connected with large hoses between two fire hydrants, which creates a temporary loop in the water distribution system. A pump on the unit circulates water at prescribed velocities where it is passed through a series of filters which remove intentionally stirred up sediment and particulate matter, including bio-film.
Disinfectant can be added to further improve water quality and ensure its safety, something current methods cannot achieve. Inline turbidity meters indicates when desired clarity levels are met, taking the guess work out of knowing when the flushing has achieved its purpose. The result is improved water quality, increased disinfectant residuals, conservation of two vital natural resources - water and the energy it took to pump and produce it - all at a lower cost without taking the value of the saved water into account! Since very little water is lost with the NO-DES Process, NPDES issues are eliminated. Additionally, the flushing can be done by a crew of 2-3 operators, typically doesn't require that any sections of the distribution system be valved off, and there is no pressure loss in the system.
Video Description
It starts off with the NO-DES unit connected to the hydrant (not running yet).
Then the water main is exposed, first notice the normal direction of distribution system flow inside the water main. The brown line located inside the water main represents settled particulates.
Once the unit is started you will see the flow from the NO-DES unit reverse the direction of the normal distribution system flow inside the water main. You can also see the flow inside the NO-DES unit, hoses, and now the hydrant runs. The most important point shown now is that the only section of main being flushed is located between the two hydrant runs.
Note: The normal distribution system flow inside the water main is now represented by the white particles (from the left) flowing up the left hydrant run, thru the NO-DES system, then back down the right hydrant run and then continues on its normal direction of flow off to the right. This was illustrated in white so the viewer could follow its flow path thru the NO-DES unit; obviously the normal direction of distribution system flow cannot continue to flow straight thru the main while the NO-DES unit is in operation, because of the high rate of the NO-DES circulated water flowing in the reverse direction. All of the water flowing from the outlet of the NO-DES unit has been filtered down to one micron absolute, so the customers downstream are receiving clean (unstirred) water. The customers upstream are also receiving clean (unstirred) water, because the normal direction of distribution system flow prevents the NO-DES hydraulic circulating action from flowing beyond the point where the left hydrant run connects to the main. This is the primary benefit of the patented Reverse Flow Method!
During the NO-DES flushing segment you will see the particulates are now being stirred-up and filtered out by the NO-DES filters. You will also see the filters change color to indicate that their capturing the stirred-up sediments.
Next you will see the water in the main run clear (the NO-DES flushing cycle is complete when the turbidity reading drops below 1.0 NT's).
At last you will see the NO-DES process stopped and normal direction of distribution system flow inside the water main resumes. Notice that the brown line located inside the water main that represented settled particulates is now cleaned, but only where the NO-DES circulated water was present.
Instead of water flowing out of fire hydrants and running to waste, the NO-DES process utilizes a trailer mounted pumping, filtering and re-chlorinating system which circulates the water within the water distribution system. The NO-DES unit is connected with large hoses between two fire hydrants, which creates a temporary loop in the water distribution system. A pump on the unit circulates water at prescribed velocities where it is passed through a series of filters which remove intentionally stirred up sediment and particulate matter, including bio-film.