Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgMon, 06 Oct 2008 23:40:04 GMT20http://www.wef.org/TechnicalDiscussions/Topic8675-10-1.aspxNo easy answer here. it could be many different things some scum, straggler floc, very much like the other biological processes in your plant. The same applies here in the digesters also pH, alkalinity, digester loadings, detention time. It is not unusual for most plants not to have some particulate in the digester supernatant. Is your decant normally free of solids? Are these aerobic or anaerobic? Wed, 19 Mar 2008 15:27:48 GMTJ.W.Kochhttp://www.wef.org/TechnicalDiscussions/Topic8675-10-1.aspxHello,<br> I was hoping someone out there might be able to suggest some reasons why some solids may not settle out of digester supernate in an unmixed secondary digester, causing solids to be drawn off with the supernate. There's a scum layer and also solids that have settled out but, for some reason, stray solids remain unsettled in the supernate.<br> The only possible cause I came up with was filamentous organisms but any other suggestions would be welcomed.<br><br>Thanks.Wed, 19 Mar 2008 10:46:46 GMTmjwboofer