I have a high tech septic system that uses essentially a sprinkler irrigation drip system for the leach field. (The effluent has been processed by a sophisticated filter system so that it is essentially water with a slight color and no smell). The field is uphill from a dosing tank and pump that puts water at 20 psi through a number of 1" lines with 2 gph emitters spaced every 2 feet. When the pump turns off, the entire field is supposed to drain back into the tank. To facilitate this, there are two vacuum relief valves --
see
http://www.geoflow.com/wastewater/w_pdfs/PS%20Air%20Vacuum%20Relief%20pg%2052%20web.pdf
located at the high corners of the field that allow air into the system so that theoretically all water drains out of the drip lines.
The problem is that these valves burp water every time the pump comes on, which is inherent in the design. There is a ball that is pushed up by the water pressure, closing the air passage, but not before a slight amount of water escapes. In a freezing climate in the winter, the water freezes and eventually blocks the air passage. This causes the entire field to freeze because it stops draining properly -- bad.
Yes, I can heat tape the valves and insulate around them, which I plan on doing. However, there has got to be a better vacuum relief valve out there that does not burp. Any suggestions?
Thanks.