Comparison of porous and non-porous media in upflow anaerobic filters when treating dairy wastewater

Abstract

The performance of porous and non-porous media in two mesophilic anaerobic upflow filters treating a wastewater from a milk bottling factory was investigated. The results indicated that at higher OLRs the porous media had a much better performance. The reactor with non-porous packing showed instability above an OLR of 4 kg COD/m 3 ·d whereas the reactor with the porous packing was still stable at OLRs of up to 21 kg COD/m 3 ·d. The behaviour of the media and biomass wash-out were observed at high upflow velocities (UV) and results demonstrated that porous media was not as susceptible to shear stresses as non-porous media. At the end of the investigation, attachment studies were carried out and the results showed a heavy biomass attachment in the porous media, whereas mainly unattached biomass was retained in the voids of the non-porous media.