Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgSat, 22 Nov 2008 02:15:00 GMT20http://www.wef.org/TechnicalDiscussions/Topic3034-11-1.aspxJeff is right. Just a word of caution on the plugging of the manhole though and you might already know this. If you use a pnematic plug it will need a release valve bought to the surface. You probably should plug the upstream side of the manhole downstream from the syphon because if you have them on the outlet of the downstream manhole they really go when you release the pressure. A rope on the plug won't hold it and the plug will reach light speed by the time it is at the downstream manhole. Plugging of the downstream manhole allows a more dignified release of the plug but it should still be roped and the valve bought to the surface.</P><P>There are some industry published safety procedures on manhole plugging but i don't have a link.</P><P>Regards</P><P>TerryFTue, 24 Jun 2008 17:16:38 GMTTerryFhttp://www.wef.org/TechnicalDiscussions/Topic3034-11-1.aspx<div class="Quote">Any tricks to cleaning low flow inverted siphons? My system has 11 of them; half have<br><br>very few residences on them, causing solids buildup. Jetting/checks must be done at<br><br>least once a week, sometimes more. In addition to the solids, there is a grease build<br><br>up. Any suggestions? </div><br>What are the sewer pipe diameters in the siphons?<br><br>Grease buildup probably needs to be cleaned by dragging a ball through the section periodically, if flushing doesn't remove most of the material.<br><br>If the pipe diameters are not too large, perhaps you could use a water tanker with fairly large-sized discharge valve, and just flood the nearest up-hill manhole to an elevation sufficient to drive the settled solids out of the low point of the line. You may want to also momentarily plug the inlet to the "flushing manhole" during the flushing process so that you get maximum head behind the column of water in the manhole. That is pretty much what the regular cleaning units do (although I'm not sure then bother to plug the inlet to the manhole).<br>Tue, 24 Jun 2008 16:37:56 GMTJeff Naumannhttp://www.wef.org/TechnicalDiscussions/Topic3034-11-1.aspxHello. I'm working with a similar case. We are considering different solutions; e.g. pumpes and flushing tanks. Maybe something like this is possible?Tue, 24 Jun 2008 03:53:39 GMTOleKhttp://www.wef.org/TechnicalDiscussions/Topic3034-11-1.aspxAny tricks to cleaning low flow inverted siphons? My system has 11 of them; half have</P><P>very few residences on them, causing solids buildup. Jetting/checks must be done at</P><P>least once a week, sometimes more. In addition to the solids, there is a grease build</P><P>up. Any suggestions?Sun, 15 Oct 2006 15:23:58 GMTJohn Pampaloni Jr.