Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgThu, 21 Aug 2008 18:11:09 GMT20http://www.wef.org/TechnicalDiscussions/Topic4074-7-1.aspxHello,<br>The best method of cleaning your membranes depends on what kind of fouling you have. If you are dosing formic acid then you may be able to clean out the slits. Formic is harder to entrain in the airstream than hydrochloric but I've seen it work. <br><br>However if the fouling that you are experiencing is on the surface of the membranes, this can also be a problem, and the in-situ dosed acid will never remove that. In order to clean the tops of the membranes you have to drain the tank and spray acid or acid replacement product. A garden sprayer works well for this job, and we've had a lot of success where there are calcium salts on the membrane surface using diluted Urea Hydrochloride instead of acid. It's safer to work with and has the same effect on calcium as acid.<br><br>Another possibility is that the membranes have been oxidized by something in the wastewater. If the membranes are EPDM look out for amamines, chlorines, acids (long term exposure), fats, oils, greases and aromatics. If these have oxidized your membrane no amount of acid will return them to their original physical properties or performance.<br><br>Slick surfaces like PTFE coated EPDM membranes work well to resist calcium type fouling, and alternate substrate materials like VitonTM, nitrile, PU, neoprene, or silicone may be useful<br>in lieu of EPDM if your problems are coming from chemical oxidation of the rubber. <br><br>-Tom Frankel<br>www.stamfordscientific.com<br><br>Manufacturers of fine bubble diffusers <br><br>Tue, 20 Feb 2007 17:47:25 GMTTomFrankelhttp://www.wef.org/TechnicalDiscussions/Topic4074-7-1.aspx<DIV>I would like to know if it exists a method of fine pore membrane diffuser cleaning more efficiently than we use in our plant of wastewater treatment. We dose formic acid, and I want to know advantages, disadvantages, in order to know the best options and give some ideas about mi degree project. I accept every technical information, links... I would be very grateful</DIV><DIV> </DIV><DIV>Thank you for your help</DIV>Wed, 14 Feb 2007 11:08:52 GMTsonine