Increasing salinity concentrations determine the long-term participation of methanogenesis and sulfidogenesis in the biodigestion of sulfate-rich wastewater

Author(s)

Oliveira, Cristiane Arruda ^[1] ; Fuess, Lucas Tadeu ^{[1, 2]} ; Soares, Lais Americo ^[1] ; Rissato Zamariolli Damianovic, Marcia Helena ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn EESC, Ctr Res Dev & Innovat Environm Engn, Biol Proc Lab, Av Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo DEQ EP USP, Polytech Sch, Chem Engn Dept, Av Prof Lineu Prestes 580, Bloco 18, BR-05508000 Conjunto Das Quimicas, SP - Brazil

• Document type: Journal article
• Source: Journal of Environmental Management; v. 296, OCT 15 2021.
• Web of Science Citations: 0

Abstract

The competition between sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) depends on several factors, such as the COD/SO42- ratio, sensitivity to inhibitors and even the length of the operating period in reactors. Among the inhibitors, salinity, a characteristic common to diverse types of industrial effluents, can act as an important factor. This work aimed to evaluate the long-term participation of sulfidogenesis and methanogenesis in the sulfate-rich wastewater process (COD/SO42- = 1.6) in an anaerobic structured-bed reactor (AnSTBR) using sludge not adapted to salinity. The AnSTBR was operated for 580 d under mesophilic temperature (30 degrees C). Salinity levels were gradually increased from 1.7 to 50 g-NaCl L-1. Up to 35 g-NaCl L-1, MA and SRB equally participated in COD conversion, with a slight predominance of the latter (53 +/- 11%). A decrease in COD removal efficiency associated with acetate accumulation was further observed when applying 50 g-NaCl L-1. The sulfidogenic pathway corresponded to 62 +/- 17% in this case, indicating the inhibition of MA. Overall, sulfidogenic activity was less sensitive (25%-inhibition) to high salinity levels compared to methanogenesis (100%-inhibition considering the methane yield). The wide spectrum of SRB populations at different salinity levels, namely, the prevalence of Desulfovibrio sp. up to 35 g-NaCl L-1 and the additional participation of the genera Desulfobacca, Desulfatirhabdium, and Desulfotomaculum at 50 g-NaCl-1 explain such patterns. Conversely, the persistence of Methanosaeta genus was not sufficient to sustain methane production. Hence, exploiting SRB populations is imperative to anaerobically remediating saline wastewaters. (AU)

• FAPESP's process: 15/06246-7 - Biorefinery concept applied to biological wastewater treatment plants: environmental pollution control coupled with material and energy recovery
• Grantee: Marcelo Zaiat
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/22952-4 - Treatment of oil and gas produced water, with autotrophic denitrification using sulfide, associated with the washing of biogas produced in anaerobic reactor
• Grantee: Cristiane Arruda de Oliveira
• Support Opportunities: Scholarships in Brazil - Doctorate