Sulfate reduction in a sludge gradually acclimated to acetate as the sole electron donor and its potential application as inoculum in a microbial fuel cell

Abstract

The aim of the present work was to btain a sulfidogenic sludge capable of th iving with acetate and evaluate its potential application as a source of microorganisms in a microbial fuel cell (MFC). The results showed that sulfate (SO−2 4 ) to sulfide (HS−) conversion increased from 74 ± 0.39% with a fed consisting of a mixture acetate:butyrate, to 85 ± 0.34% with a fed containing only acetate. The sulfate removal rate (SRR) was of 1755.30 ± 50 mg SO−2 4 gVSS −1 L⁻¹ d⁻¹ and sulfate reducing activity (SRA) 155.21 ± 30 mg COD-H2S gVSS−1 d−1 with the mixture and SRR 1692.31 ± 39 mg SO−2 4 gVSS −1 L⁻¹ d⁻¹ ; SRA 184.25 ± 24 mg COD-H2S gVSS−1 d−1 with acetate. The COD removal increased from 66 ± 0.8% with the mixture to 81 ± 0.39%, with acetate. The open circuit voltage increased from 0.668 to 0.788 V with acetate. The results suggested that this sludge could be utilized to recover energy that could be eventually susceptible to storage for further utilization while reducing sulfate and avoiding accumulation of acetate.

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Identifiers

DOI

10.24275/rmiq/rmiq/ia805

Journal

Revista Mexicana de Ingeniería Química

Year

2020