Standpipe Backwash
Standpipe Backwash
(OP)
I am having a real hard time wrapping my mind around this concept. I am working with a filter manufacturer who likes to backwash with the use of a standpipe. This is for an industrial waste water process where water is pumped from a wet well through the filters and back out to drain. The backwash water is taken directly from a filter discharge and is sent through an adjacent filter in backwash mode.
I've been on the phone with their engineer, but there is a communication gap. My understanding of the concept is that there is an open standpipe on the discharge side of the filter bank. The water level in the pipe is several feet higher than the top of the filters. I am told that this insures enough head to backwash the filters (one at a time).
Here's my problem, the only way to raise the water up in the standpipe is to pump it up there, right? So if I have enough pump head to raise the water up, I have enough pump head to backwash the filters, right? If that's true, then what do I need an open standpipe for? It seems to me that the potential for disaster is great with an open pipe on the discharge side of the pump. Wouldn't I be better off maintaining a pressure on the discharge side of the filters so that I will have enough to backwash?
What am I missing here?
I've been on the phone with their engineer, but there is a communication gap. My understanding of the concept is that there is an open standpipe on the discharge side of the filter bank. The water level in the pipe is several feet higher than the top of the filters. I am told that this insures enough head to backwash the filters (one at a time).
Here's my problem, the only way to raise the water up in the standpipe is to pump it up there, right? So if I have enough pump head to raise the water up, I have enough pump head to backwash the filters, right? If that's true, then what do I need an open standpipe for? It seems to me that the potential for disaster is great with an open pipe on the discharge side of the pump. Wouldn't I be better off maintaining a pressure on the discharge side of the filters so that I will have enough to backwash?
What am I missing here?




