Attachment, strength and performance of a porous media in an upflow anaerobic filter treating dairy wastewater

Attachment, strength and performance of a porous media in an upflow anaerob ic filter (UFAF) treating dairy wastewater were investigated. Microscopic e xamination showed that the number of autofluorescent methanogens varied 15- 28% of the number of total bacteria along the UFAF while the number of viab le methanogens was 10-70 times less that of autofluorescent methanogens. Th e most dominant species was found to be Methanococcus followed by short rod s, medium rods, long rods, filaments and Methanosarcina. The quantity of at tached biomass was the highest at the bottom, 103 mg VSS/media ring and low est at the top, 23 mg VSS/media ring and an average of 55 mg VSS/media ring in the mid-height inside the UFAF. An average of 50% reduction in compress ive strength of the sintered glass media after 8 months of operation was me asured. The UFAF was operated up to an organic loading rate of 21 kg COD/m( 3).d with a hydraulic retention time of 0.5 day and an average of 80% COD r emoval efficiency for most of the operating period was achieved.