Upflow anaerobic sludge blanket in microalgae-based sewage treatment: Co-digestion for improving biogas production

Lucas Vassalle; Rubén Díez-Montero; Alcino Trindade Rosa Machado; Camila Moreira; Ivet Ferrer; Cesar R Mota; Fabiana Passos

doi:10.1016/j.biortech.2019.122677

Upflow anaerobic sludge blanket in microalgae-based sewage treatment: Co-digestion for improving biogas production

Bioresour Technol. 2020 Mar:300:122677. doi: 10.1016/j.biortech.2019.122677. Epub 2019 Dec 25.

Authors

Lucas Vassalle¹, Rubén Díez-Montero², Alcino Trindade Rosa Machado³, Camila Moreira³, Ivet Ferrer², Cesar R Mota³, Fabiana Passos³

Affiliations

¹ Department of Sanitary and Environmental Engineering, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Belo Horizonte, MG, Brazil; GEMMA - Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain. Electronic address: lvassalle@ufmg.br.
² GEMMA - Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain.
³ Department of Sanitary and Environmental Engineering, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Belo Horizonte, MG, Brazil.

PMID: 31901777
DOI: 10.1016/j.biortech.2019.122677

Abstract

Upflow anaerobic sludge blanket (UASB) reactors are widely used to treat domestic sewage and frequently require post-treatment. Little is known about the use of high rate algal ponds (HRAP) for post-treating UASB reactors' effluent. This study aimed to evaluate a UASB reactor followed by a HRAP in terms of sewage treatment efficiency and biogas production, during one year at demonstration-scale. The UASB reactor co-treated raw sewage and the harvested microalgal biomass from the HRAP, which was recirculated to the reactor. An identical UASB reactor, treating only raw sewage, was used as control. The results showed an overall removal of 65% COD and 61% N-NH₄ in the system. Furthermore, methane yield was increased by 25% after anaerobic co-digestion with microalgae, from 156 to 211 NL CH₄ kg^-1 VS. An energy assessment was performed and showed a positive energy balance, with a net ratio of 2.11 to the annual average.

Keywords: Bioenergy recovery; Biogas; High rate algal pond; Sewage; UASB reactor.

MeSH terms

Anaerobiosis
Biofuels
Bioreactors
Methane
Microalgae*
Sewage*
Waste Disposal, Fluid

Substances

Biofuels
Sewage
Methane