TY  - JOUR
AU  - Diniz, B. C.
AU  - Wilfert, P.
AU  - Sorokin, D. Y.
AU  - Loosdrecht, M. C. M. van
PY  - 2025//
TI  - Anaerobic digestion at high-pH and alkalinity for biomethane production: Insights into methane yield, biomethane purity, and process performance
JO  - Bioresource Technology
SP  - 132505
VL  - 429
KW  - Anaerobic digestion
KW  - High-pH
KW  - High-alkalinity
KW  - Biogas upgrading
KW  -
KW  - Alkaline waste
N2  - The role of high-pH conditions in anaerobic digestion (AD) has traditionally been confined to it’s use in pre-treatment processes. However, operating AD at elevated pH and alkalinity offers significant advantages, including in-situ upgrading of biogas to biomethane. This study examines the potential and scalability of AD under these conditions (pH ∼ 9.3; alkalinity ∼ 0.5 eq/L). The substrate used was the alkaline waste generated from the extraction of extracellular polymeric substances (EPS) from aerobic granular sludge (AGS), and the inoculum used was a haloalkaliphile microbial community from soda lake sediments. To evaluate the system’s performance, the organic loading rate (OLR) was incrementally increased. The highest methane production obtained was 8.4 ± 0.1 mL/day/gVSadded at a hydraulic retention time (HRT) of 15 days and an OLR of 1 kgVS/day/m3. At this loading rate, methanogenesis became the rate limiting conversion. The maximum volatile solids conversion was 48.1 ± 1.1 %. Throughout the reactor operation, methane purity in the biogas consistently exceeded 90 % peaking at 96.0 ± 0.2 %, showcasing the potential for in-situ biogas purification under these conditions. In addition, no ammonia inhibition was observed, even with free-ammonia (NH3) concentrations reaching up to 14 mM. This study underscores the potential of high-pH anaerobic digestion as a sustainable method for both waste treatment and energy recovery.
SN  - 0960-8524
UR  - https://www.sciencedirect.com/science/article/pii/S0960852425004717
N1  - exported from refbase (http://www.uhydro.de/base/show.php?record=305), last updated on Thu, 28 Aug 2025 13:27:30 +0200
ID  - Diniz_etal2025
ER  -