In sludge treatment by digester and methane production, efficient sludge conversion to biogas and productivity are dictated by the microbial work. If the volume of gas generated by mass of sludge could be increased, then less sludge needs to be transported and more gas is being produced which could potentially increase profits by reducing costs. Currently it is possible to increase the microbial work by using chitosan as a carrier for bacterial growth. The issue is that the chitosan is degraded during digestion and it is generally more expensive to use. The question was: would it be possible to increase productivity using a more economical carrier which does not get degraded during digestion?
MAT250 silica hollow microsphere was added to an anaerobic digester as bacteria carrier. Results showed that biogas production was increased by 30% compared to a digester without bacterial carrier. Compared to chitosan, biogas production was equivalent. It was then concluded that the use of silica microspheres was an economical means of increasing biogas production and reduce volatile sludge content.