Case Study of Glycerin in Wastewater Treatment

• Glycerin was used as an external carbon source to remove nitrogen from wastewater during municipal wastewater treatment in two independent activated SBR-type sludge reactors.
• External carbon sources are often fundamental to achieving high efficiency of sewage treatment. Glycerol, a waste product and a by-product of biodiesel production, showed significant potential as an external carbon source. Previous studies described glycerol as a suitable carbon source in wastewater treatment, and useful to reduce biomass production.
• A single cycle of each reactor lasted six hours in the sewage supply (2 minutes), mixing (60 minutes), aeration (3.5 hours), sedimentation (60 minutes), and decantation (30 minutes) phases. Glycerol in 100 mg/dm3 wastewater was added to one of the two sludge chambers (R2) in each cycle about 20 minutes after sewage pouring. In contrast, the other reactor (R2) did not receive any external carbon source.
• The results showed a higher nitrogen removal efficiency in the reactor that received glycerin than the reactor without an external carbon source.

Data on Biodiesel and Foaming Reduction

• The removal of lipids in wastewater treatment results in a highly digestible aqueous solution, and the anaerobic digestion of this solution produces high-quality biogas.
• Lipids extracted during wastewater treatment eliminate or reduce foaming within aerobic digesters significantly, as aerobic microbial cell formations are faster. The cells can be further removed to produce more lipids for biodiesel production.
• Biogas is often associated with the digestion of waste solids within anaerobic digesters in wastewater treatment and costs between $2-$8 per thousand cubic feet of gas market value.