Enhanced removal of humic acid from piggery digestate by combined microalgae and electric field

• Published in: Bioresource technology Vol. 347; p. 126668
• Main Authors: Luo, Longzao, Li, Miao, Luo, Shuang, Kumar Awasthi, Mukesh, Lin, Xiaoai, Liao, Xing, Peng, Changsheng, Yan, Binghua
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2022
• Subjects: Biomass; Electric field; Electrical intensity; Humic acid; Humic Substances; Microalgae; Nitrogen; Phosphorus; Waste Water - analysis; pH; Microalgae; Electric field; Humic acid; Electrical intensity
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2021.126668

[Display omitted] •Electric field was used to enhance the removal of humic acid (HAs) by microalgae.•The influencing factors for the removal of HAs were investigated.•Removal efficiency of HAs by electric field-microalgae system (EFMS) was 55.38%.•The removal of HAs were due to the oxidation, coagulation and assimilation by EFMS. Microalgae technology is a promising method for treating piggery digestate, while its removal ability of humic acids (HAs) is poor. Here, an electric field-microalgae system (EFMS) was used to improve the removal of HAs from the piggery digestate. Results indicated that the removal of HAs by EFMS relied on the initial concentration of HAs, electrical intensity, the initial inoculation concentration of microalgae and pH. Values of these parameters were optimized as electrical intensity of 1.2 V/cm, microalgae initial inoculation concentration of 0.1 g/L and pH 5.0. The HAs removal efficiency by EFMS (55.38%) was 13% and 38% higher than that by single electric field and microalgal technology. It was observed that oxidation, coagulation and assimilation contributed to the removal of HAs, suggesting that EFMS could serve as an attractive and cost-effective technique for the removal of HAs from the piggery digestate.