A combined acidic fermentation and anaerobic digestion (AD) treatment has been developed on pilot scale for urban bio-waste conversion into volatile fatty acid (VFA) and biogas. The specific waste mixture was composed by the pre-treated organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS), both produced inside the Treviso (northeast Italy) municipality. The effect of temperature (37 °C and 55 °C) was investigated in both steps. Only the mesophilic fermentation process provided a VFA-rich stream (19.5 g COD VFA /L) with stable physical-chemical features, with no need of chemicals addition for pH control. The sludge buffering capacity made this step technically feasible. The AD step was performed on the solid-rich fraction of fermented bio-waste, after dilution with excess WAS. No relevant differences were observed under the two investigated temperature: in the steady state (organic loading rate of 2.5 kg VS/m 3 d), the specific biogas production was 0.40 and 0.45 m 3 /kg VS at 37 °C and 55 °C respectively, with similar CH 4 content (63–64% v/v). The scaled-up version of the system (in an average urban municipality of 170,000 Person Equivalent) revealed that the whole process is thermally sustainable if both reactors are operated at mesophilic temperature: 36% of surplus thermal energy and 13,03 MWh/d of produced electricity, which corresponds to a revenue of 609,605 €/year. In addition, 2,262 kg COD VFA /d are available for parallel purposes, such as the synthesis of bio-products with higher added value than bio-methane (e.g. biopolymers).

Novel routes for urban bio-waste management: A combined acidic fermentation and anaerobic digestion process for platform chemicals and biogas production

Valentino, Francesco
Writing – Original Draft Preparation
;
Moretto, Giulia
Formal Analysis
;
Gottardo, Marco
Data Curation
;
Pavan, Paolo
Supervision
;
2019

Abstract

A combined acidic fermentation and anaerobic digestion (AD) treatment has been developed on pilot scale for urban bio-waste conversion into volatile fatty acid (VFA) and biogas. The specific waste mixture was composed by the pre-treated organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS), both produced inside the Treviso (northeast Italy) municipality. The effect of temperature (37 °C and 55 °C) was investigated in both steps. Only the mesophilic fermentation process provided a VFA-rich stream (19.5 g COD VFA /L) with stable physical-chemical features, with no need of chemicals addition for pH control. The sludge buffering capacity made this step technically feasible. The AD step was performed on the solid-rich fraction of fermented bio-waste, after dilution with excess WAS. No relevant differences were observed under the two investigated temperature: in the steady state (organic loading rate of 2.5 kg VS/m 3 d), the specific biogas production was 0.40 and 0.45 m 3 /kg VS at 37 °C and 55 °C respectively, with similar CH 4 content (63–64% v/v). The scaled-up version of the system (in an average urban municipality of 170,000 Person Equivalent) revealed that the whole process is thermally sustainable if both reactors are operated at mesophilic temperature: 36% of surplus thermal energy and 13,03 MWh/d of produced electricity, which corresponds to a revenue of 609,605 €/year. In addition, 2,262 kg COD VFA /d are available for parallel purposes, such as the synthesis of bio-products with higher added value than bio-methane (e.g. biopolymers).
File in questo prodotto:
File Dimensione Formato  
JCLEPRO-D-18-13818_R2.pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: Accesso libero (no vincoli)
Dimensione 1.48 MB
Formato Adobe PDF
1.48 MB Adobe PDF Visualizza/Apri
Valentino JCLP 2019.pdf

non disponibili

Tipologia: Versione dell'editore
Licenza: Accesso chiuso-personale
Dimensione 1.08 MB
Formato Adobe PDF
1.08 MB Adobe PDF   Visualizza/Apri

I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/3712590
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 38
  • ???jsp.display-item.citation.isi??? 32
social impact