Details

Autor(en) / Beteiligte

• Seyedi, Saba
• Venkiteshwaran, Kaushik
• Zitomer, Daniel

Titel

Current status of biomethane production using aqueous liquid from pyrolysis and hydrothermal liquefaction of sewage sludge and similar biomass

Ist Teil von

• Reviews in environmental science and biotechnology, 2021-03, Vol.20 (1), p.237-255

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2021

Link zum Volltext

Quelle

SpringerLink (Online service)

Beschreibungen/Notizen

• Pyrolysis and hydrothermal liquefaction (HTL) are potential technologies for renewable energy production and waste valorization using municipal wastewater sewage sludge and other lignocellulosic biomass. However, the organic-rich aqueous pyrolysis liquid (APL) and HTL aqueous phase (HTL-AP) produced currently have no apparent use and are challenging to manage. Furthermore, the toxic organic compounds in them can be harmful to the environment. Anaerobic digestion (AD) may be a viable method to manage the liquids and recover energy in APL and HTL-AP in form of methane-rich biogas. Integrating thermochemical processes with AD could promote a circular economy by recovering resources and reducing environmental pollution. The challenge, however, is the presence of toxic compounds recalcitrant to anaerobic biodegradation such as phenols and nitrogen-containing organics that can inhibit methane-producing microbes. This review presents information on APL and HTL-AP characterization and biodegradability. Feedstock composition and process operational parameters are major factors affecting APL and HTL-AP composition, subsequent toxicity, and degradability. Feedstocks with high nitrogen content as well as increased thermochemical processing temperature and retention time result in a more toxic aqueous liquid and lower methane yield. Dilution and low AD organic loading are required to produce methane. More comprehensive APL and HTL-AP chemical characterization is needed to adopt suitable treatment strategies. Pretreatments such as overliming, air stripping, partial chemical oxidation, adsorption, and solvent extraction of toxic constituents as well as co-digestion and microbial acclimatization successfully reduce toxicity and increase methane yield. Graphic abstract