Assessment of biogas production in Argentina from co-digestion of sludge and municipal solid waste

MORERO, BETZABET; VICENTIN, ROCIO; CAMPANELLA , ENRIQUE A.

Conferencia; 2nd RCN Conference on Pan American Biofuels & Bioenergy Sustainability; 2016

In Argentina there is animportant potential to utilize organic waste as a source of bioenergygeneration. This work analyzes the environmental impacts, energetic andeconomic requirements of biogas production by digestion of the sludge (SS)produced in a wastewater treatment plant of a medium city of Argentina. The SSis co-digested with the organic fraction of municipal solid waste (OFMSW) andthe basis of the study is the life cycle assessment (LCA). The LCA is performedaccording to ISO 14040-44 using the SimaPro simulator. In a first stage, thetransport of the different raw materials to the biogas plant was defined. Then,the co-digestion and the biogas treatment for final use were evaluated. Theco-digestion was improved with glycerol and the generation of biogas was estimatedwith the GPS-X software. Two alternatives of biogas end use were considered: combinedheat and power (CHP) and biomethane generation. For the first option H2S isremoved from the raw biogas stream, while the second option also removes CO2.The H2S removal process was simulated in the SuperPro software by anaerobicbiofiltration. The same software was used to simulate the removal of CO2 absorption-desorptionwith water as solvent. Finally the environmental impacts related to the end useof biogas (CHP and biomethane) were evaluated.The environmental analysis showed that the use of organic waste as an energysource, solving problems related to waste disposal, generates lessenvironmental impact and lower costs than conventional disposal in a landfill.The feed to the digester needs to be big enough for a more economic attractivebiogas production; then the disposal of organic waste (OFMSW + SS) of amedium-sized city should be complemented with waste from nearby towns oragricultural/livestock waste.  The energybalance is highly positive with the use of energy for the overall process(Feedstock collection and transport, Anaerobic Digestion, Digestate Managementand Biogas Treatment Plant) between 30 to 39% of the energy generated.