Work

Electrochemical pretreatment to improve the biodegradability and valorization of waste activated sludge from aerobic wastewater treatment plants

Year: 2025

Type: article

Abstract: Waste activated sludge (WAS) represents a significant operational and environmental challenge for wastewater treatment plants (WWTPs) due to its low biodegradability, attributed to extracellular polymeric substances (EPS) that hinder enzymatic hydrolysis. Electrochemical (EC) pretreatment has shown promise in improving organic matter solubilization. However, conventional systems often face limitations related to high energy demand, mineralization of organic matter and electrode degradation. This study evaluates EC pretreatment with two dimensionally stable anodes, Ti/RuO 2 and Ti/RuO 2 –ZrO 2 –Sb 2 O 5 , as scalable alternatives for improving WAS biodegradability and energy recovery. The EC with both electrodes using WAS as the sole electrolyte, with an applied current of 10 mA/cm 2 for 30 min, achieved significantly enhanced solubilization with minimal mineralization. This effectively enhances the anaerobic biodegradability of WAS and increases methane recovery while maintaining low energy consumption and avoiding chemical additives. Methane yields increased to 168 and 342 N-L CH4 /kg VS for WAS pretreated with Ti/RuO 2 and Ti/RuO 2 –ZrO 2 –Sb 2 O 5 , respectively, compared to 85 N-L CH4 /kg VS for untreated sludge. Energy analysis revealed a net gain of 1.64 kW-h/kg VS , outperforming other EC systems reported in the literature. In this sense, the implementation of this process could be integrated at an industrial scale in WWTPs as a cost-effective strategy for sludge valorization and resource recovery, in line with circular economy principles.

Source: Biotechnology for Biofuels and Bioproducts

DOI: 10.1186/s13068-025-02693-8

Authors: Selene González-Ledesma, Ma. Concepción Romero-Serrano, Víctor Sánchez-Vázquez, Ignacio González, Ulises Durán-Hinojosa

Institution: Universidad Autónoma Metropolitana

Language: English

Topic: Anaerobic Digestion and Biogas Production

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Affordable and clean energy, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $2,440