Biostimulation of anaerobic digested wastewater using magnetic nanoparticles and an external magnetic field for biogas enhancement

Abstract

Energy‐driven wastewater treatment plants (WWTP) have become an interesting research focus for environmental and process engineers. To meet the rigorous discharge limit standards imposed by the environmental protection agency (EPA) and South African national standards (SANS), the conventional treatment method has been improved and advanced technologies have been adapted. As such, studies on magnetized anaerobic digestion systems for wastewater treatment with the concept of energy generation have been explored. The present study evaluated the effect of an external magnetic field (MF) on biochemical methane potential (BMP) tests using magnetic nanoparticles (MNP) for wastewater treatment. Two BMP systems were compared, where both systems were dosed with Fe3O4 (MNP) and operated at 35 °C for 10 days. One of the systems (control) was not exposed to the magnetic field while the other system had 3 h of 20 mT magnetic field exposure on daily basis. The system exposed to the magnetic field showed better performance in terms of biogas enhancement and the treatability of the wastewater. About 85% chemical oxygen demand (COD) of the wastewater (350 mg.L–1 COD remaining) was degraded by the MF, which resulted in 72% color removal, 210 mL.day–1 biogas produced and 97% methane. On other hand, 75% COD was degraded by the control system, which resulted in 175 mL.day–1 biogas and 94% methane. Exposing the BMP system coupled with MNPs to an external magnetic field was found to be feasible and promising in terms of biogas production and color removal. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Synthesis and characterization of magnetic nanoparticles via co‐precipitation: Application and assessment in anaerobic digested wastewater

“…The use of iron‐based NPs to boost methane and biogas generation, as reported by Liang et al ., 63 was observed. The MNPs addition had a good impact on methanations in addition to biogas production 24,65 …”

“…After the 21 and 30 day incubation periods, the reactor efficiency was assessed by monitoring the contaminants removal using Equation (2). The analytical method used previously 24 was adopted in this study to determine the water quality.…”

“…Co‐precipitation, being simple in nature, was examined alongside calcination for the synthesis of MNPs in this work and the resultant MNPs were applied in a biological system for biogas production from wastewater and sludge. The application of NPs in anaerobic digestion has been studied by several research to understand the impact of NPs on biogas and methane yield 4,22–27 …”

“…The application of NPs in anaerobic digestion has been studied by several research to understand the impact of NPs on biogas and methane yield. 4,[22][23][24][25][26][27] Tetteh, Amo-Duodu and Rathilal 26 examined the impact of four distinct MNPs (Fe 2 O 4 -TiO 2 , Cu-Fe 2 O 4 , Fe 3 O 4 and chitosan-Fe 2 O 4 /TiO 2 ) on the performance of the anaerobic digestion process for wastewater treatment. Their results recorded the highest yield of biogas (400 mL/day) with about 100% methane yield for the bioreactor with Fe 2 O 4 -TiO 2 MNP as compared with the rest of the bioreactors.…”

Applying Dynamic Magnetic Field To Promote Anaerobic Digestion via Enhancing the Electron Transfer of a Microbial Respiration Chain

“…Masood et al reported that applying a DMF inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa . However, current studies mainly focused on the effects of static/constant magnetic fields on anaerobic systems. − To our best knowledge, no reports have investigated the effects of DMFs on anaerobic digestion, especially on the individual stage of anaerobic digestion.…”