Addition of crude glycerine as strategy to balance the C/N ratio on sewage sludge thermophilic and mesophilic anaerobic co-digestion. (October 2015)

• Record Type: Journal Article
• Authors: Silvestre, G.; Fernández, B.; Bonmatí, A.
• Is Part Of: Bioresource technology. Volume 193(2015)
• Page Start: 377
• Page End: 385
• Publication Date: 2015-10
• Subjects: Thermophilic and mesophilic co-digestion -- Sewage sludge -- Crude glycerine -- Dewatering properties -- Inhibition; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.06.098
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Thermophilic sewage sludge co-digestion with glycerine showed great instability. Glycerine addition (1% v/v) at mesophilic range showed 148% CH4 yield increase. Glycerine addition promotes H2 and propionate specific activity of the biomass. The use of glycerine as co-substrate worsens digestate dewaterability. Abstract: The effect of adding crude glycerine during continuous sewage sludge anaerobic digestion was investigated under thermophilic and mesophilic temperatures. Addition of CGY at thermophilic temperature range showed a negative impact on stability and performance of the process, even at low doses. The extreme pH values of CGY, together with the rapid release of VFA, causes SS alkalinity fail to control pH drop. On the contrary, at mesophilic temperature range the process performs steadily, with 148% increase in methane production when CGY represented 1% v/v of the influent (27% of influent COD). Further CGY percentages did not show any added improvement; the biomass shift, due to a high C/N ratio, could explain this behaviour. Results suggested that CGY can be used as co-substrate of SS anaerobic digestion though, depending on the characteristics of CGY, and on operational conditions, different parameters should be taken into account to achieve a steady and consistent operation.