Direct membrane filtration of municipal wastewater assisted by natural tannin-based coagulant: Insights into membrane fouling and methane production

Autor(es)

Subtil, E. L. ; Mohedano, A. F. ; Diaz, E. ; de la Rubia, M. A.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 13, n. 3, p. 14-pg., 2025-06-01.

Resumo

This study evaluates the use of tannin-based coagulants in direct membrane filtration (DMF) systems for the up-concentration of organic matter in municipal wastewater and its effects on membrane fouling and methane production by anaerobic digestion. Tannin, a natural and biodegradable coagulant, was applied at concentrations of 10, 20, 30, and 50 mg L-1. The fouling behavior was hydraulic assessed by a series of filtration tests under constant flux, while external and internal foulants were widely characterized, including liquid chromatography coupled with a dissolved organic carbon analyzer. The results revealed a significant reduction in total fouling resistance, particularly external fouling associated with the formation of a cake layer. At concentration of 30 mg L-1, tannin effectively reduced external fouling by promoting particle aggregation and reducing biopolymer deposition, particularly proteins, which were reduced by up to 80 %. That coagulant concentration significantly reduces internal foulants, as evidenced by the sharp decline in biopolymer concentration (from 5.6 to 1.3 mg m-2) and the substantial reduction in humic substances (from 11.2 to 3.2 mg m-2). Moreover, the anaerobic digestion by biochemical methane potential (BMP) tests demonstrated that tannin addition enhanced early-stage methane production due to the presence of easily biodegradable organic matter, leading a methane yield of 391 mL CH4 g-1 VS. In conclusion, tannin-based coagulant presents a promising solution for improving DMF performance by reducing fouling and enhancing energy recovery through biogas production. (AU)

• Processo FAPESP: 23/18242-2 - Eficiência energética e recuperação de recursos de novo conceito de tratamento de esgoto baseado na pré-concentração de matéria orgânica e fotobiorreator com membrana (MPBR)
• Beneficiário: Eduardo Lucas Subtil
• Modalidade de apoio: Bolsas no Exterior - Pesquisa