Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgTue, 14 Oct 2008 12:21:19 GMT20http://www.wef.org/TechnicalDiscussions/Topic9072-9-1.aspxThere will be a rough correlation, but not enough to predict Bio-P success. Sewage with very little H2S will probably have very little VFA and sewage with a lot of H2S will have more VFA, but no way of knowing if it is enough for Bio-P. </P><P>We did not have good results sending VFA samples out to labs at $100 per sample, the test is apparently very hard on GC columns and the data was highly variable. We test for VFA on an ion chromatograph using a modification of a method for VFA in wine. It is automated and can run over night. The lab doesn't even whine when I send them 24 samples from a diurnal test.</P><P>We tested Bio-P in the winter when we were off our 0.070 T-P permit to see if we could do it. It worked and gave us confidence in Bio-P. It did not work on the train we kept nitrifying. We needed more VFA to denitrify the RAS. We converted gravity thickeners to series fermentation (UFAT) and made enough VFA for Bio-P and eliminated our 30 mg/l primary alum dose.Wed, 07 May 2008 10:58:43 GMTRob Baurhttp://www.wef.org/TechnicalDiscussions/Topic9072-9-1.aspxKurt,</P><P>Others may disagree but i am not convinced that there would be a reliable correlation between level of sulfide and VFA.</P><P>Regards</P><P>TerryFWed, 07 May 2008 07:19:09 GMTTerryFhttp://www.wef.org/TechnicalDiscussions/Topic9072-9-1.aspxDoes anyone know of a reliable correlation between Sulfide levels and VFA's?<P>A consultant has reassured me that if we have have reliable sulfide levels, the VFA's will be there.</P><P>We are looking at BNR in the near future and want to find a reliable way to track VFA's without the expense and effort of the VFA testing. </P><P>Our influent dissolved sulfides are consistantly 3-5 mg/l.</P><P>Thanks</P><P>Kurt W.Tue, 06 May 2008 16:51:03 GMTKW