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Transcript
00:03
The deterioration of pipes in a water distribution system is a major challenge for water utilities.
00:10
In some pipes, depending on their material and age, deposits can form on the inside walls.
00:17
This can cause hydraulic capacity to decrease over time.
00:22
Deposits can result from chemical precipitation, microbiological activity, and in the case of cast iron pipes, corrosion buildup.
00:30
Within a water distribution system, unidirectional flushing (UDF) can help to improve water quality.
00:37
Deposits can increase pipe roughness and decrease effective pipe diameter, possibly resulting in:
00:44
Inability to deliver fire flows.
00:46
Increased disinfectant demand.
00:49
Chlorine degradation.
00:52
Complaints about water taste, odor, and color.
00:56
And potentially, public health issues.
00:59
Furthermore, reduced effective pipe diameter can lead to reduced hydraulic capacity,
01:05
increased pumping costs, and lower residual pressure.
01:09
Certain pipe materials, such as cast iron, are more susceptible to these types of issues.
01:16
Unidirectional flushing can prolong the life expectancy of a distribution system and reduce the potential for waterborne diseases.
01:24
It can help remove biofilm growth and particulates that lead to chlorine loss, as well as taste, odor, and color concerns.
01:33
In InfoWater Pro UDF, unidirectional flushing is performed by first isolating a portion of the distribution system,
01:41
then opening fire hydrants or flushing valves.
01:44
These actions can ideally create enough velocity to scour pipes and remove unwanted materials.
01:50
The flushed water is then discharged through a hydrant.
01:54
Generally, unidirectional flushing begins in portions of the system closest to the water sources,
02:00
proceeding to the outward extents of the system.
02:03
It is important to understand the distinction among the three general flushing methods:
02:08
UDF, conventional flushing, and continuous blow-off.
02:13
UDF involves a systematic plan to direct flushed water in a single direction along the pipe to maximize velocity.
02:21
To do this, you close valves and open hydrants to create a one-way flow in the water mains.
02:27
This linear flow results in higher velocities,
02:31
typically 5 or 6 feet per second.
02:33
This method maximizes linear velocity near the pipe wall, making it ideal for removing biofilm and other more hardened corrosion materials.
02:42
The flush begins at a clean water source and ends at a hydrant, so that only clean water is used.
02:49
UDF also eliminates the chances of dirty water and debris being inadvertently transported
02:55
around the system and is the most efficient flushing method.
02:59
UDF is not a feasible solution in emergency situations, as it takes proper planning and time to carry out.
03:07
Conventional flushing is done without control of the flow direction—for example,
03:13
opening several hydrants in the same area at once until the water clears up.
03:17
This method is effective for removing loose sediment, but less effective at raising pipeline velocities.
03:25
Conventional flushing yields velocities of less than 2 feet per second, so it is not effective at removing deposits or biofilm.
03:33
It can also cause dirty water and debris to be inadvertently transported around the system.
03:39
As it is less effective at raising velocities, this method often requires larger amounts of water, decreasing its efficiency.
03:47
Conventional flushing is often used reactively to fix areas of poor water quality, or in response to aesthetic complaints.
03:56
Continuous blow-off consists of a small, continuous or intermittent water usage to refresh the line.
04:03
This is usually seen as a short-term preventive strategy and is often used to solve stagnation problems.
04:10
It has a comparatively low velocity of less than 1 foot per second, and can use a large amount of water, resulting in poor efficiency.
00:03
The deterioration of pipes in a water distribution system is a major challenge for water utilities.
00:10
In some pipes, depending on their material and age, deposits can form on the inside walls.
00:17
This can cause hydraulic capacity to decrease over time.
00:22
Deposits can result from chemical precipitation, microbiological activity, and in the case of cast iron pipes, corrosion buildup.
00:30
Within a water distribution system, unidirectional flushing (UDF) can help to improve water quality.
00:37
Deposits can increase pipe roughness and decrease effective pipe diameter, possibly resulting in:
00:44
Inability to deliver fire flows.
00:46
Increased disinfectant demand.
00:49
Chlorine degradation.
00:52
Complaints about water taste, odor, and color.
00:56
And potentially, public health issues.
00:59
Furthermore, reduced effective pipe diameter can lead to reduced hydraulic capacity,
01:05
increased pumping costs, and lower residual pressure.
01:09
Certain pipe materials, such as cast iron, are more susceptible to these types of issues.
01:16
Unidirectional flushing can prolong the life expectancy of a distribution system and reduce the potential for waterborne diseases.
01:24
It can help remove biofilm growth and particulates that lead to chlorine loss, as well as taste, odor, and color concerns.
01:33
In InfoWater Pro UDF, unidirectional flushing is performed by first isolating a portion of the distribution system,
01:41
then opening fire hydrants or flushing valves.
01:44
These actions can ideally create enough velocity to scour pipes and remove unwanted materials.
01:50
The flushed water is then discharged through a hydrant.
01:54
Generally, unidirectional flushing begins in portions of the system closest to the water sources,
02:00
proceeding to the outward extents of the system.
02:03
It is important to understand the distinction among the three general flushing methods:
02:08
UDF, conventional flushing, and continuous blow-off.
02:13
UDF involves a systematic plan to direct flushed water in a single direction along the pipe to maximize velocity.
02:21
To do this, you close valves and open hydrants to create a one-way flow in the water mains.
02:27
This linear flow results in higher velocities,
02:31
typically 5 or 6 feet per second.
02:33
This method maximizes linear velocity near the pipe wall, making it ideal for removing biofilm and other more hardened corrosion materials.
02:42
The flush begins at a clean water source and ends at a hydrant, so that only clean water is used.
02:49
UDF also eliminates the chances of dirty water and debris being inadvertently transported
02:55
around the system and is the most efficient flushing method.
02:59
UDF is not a feasible solution in emergency situations, as it takes proper planning and time to carry out.
03:07
Conventional flushing is done without control of the flow direction—for example,
03:13
opening several hydrants in the same area at once until the water clears up.
03:17
This method is effective for removing loose sediment, but less effective at raising pipeline velocities.
03:25
Conventional flushing yields velocities of less than 2 feet per second, so it is not effective at removing deposits or biofilm.
03:33
It can also cause dirty water and debris to be inadvertently transported around the system.
03:39
As it is less effective at raising velocities, this method often requires larger amounts of water, decreasing its efficiency.
03:47
Conventional flushing is often used reactively to fix areas of poor water quality, or in response to aesthetic complaints.
03:56
Continuous blow-off consists of a small, continuous or intermittent water usage to refresh the line.
04:03
This is usually seen as a short-term preventive strategy and is often used to solve stagnation problems.
04:10
It has a comparatively low velocity of less than 1 foot per second, and can use a large amount of water, resulting in poor efficiency.
Required for course completion
The deterioration of pipes in a water distribution system is a major challenge for water utilities. Unidirectional flushing (UDF) can help to improve water quality.
