Biological methane removal by groundwater trickling biofiltration for emissions reduction

Area of Science:

• Environmental Science
• Microbiology
• Water Treatment Engineering

Background:

• Methane removal is crucial for drinking water from methane-rich sources.
• Conventional aeration causes significant methane emissions, increasing treatment plant carbon footprints.
• Alternative methods are needed to reduce emissions and improve efficiency.

Purpose of the Study:

• To compare the performance of a trickling filter for biological methane oxidation with conventional aeration.
• To quantify the contributions of abiotic and biotic processes in methane removal.
• To characterize microbial communities and their roles in different treatment setups.

Main Methods:

• Full-scale operation of trickling filter and conventional aeration systems.
• Ex-situ batch assays for process quantification.
• Metagenome-resolved metaproteomics for microbial community analysis.

Main Results:

• Both systems achieved complete removal of methane, iron, ammonium, and manganese.
• Trickling filtration halved methane emissions by combining stripping and biological oxidation.
• Methane-oxidizing bacteria in trickling filters also contributed to ammonia oxidation.
• Biological iron oxidation was reduced in trickling filters, suggesting methane's role in chemical oxidation.

Conclusions:

• Trickling filtration effectively promotes biological methane oxidation for drinking water production.
• This method achieves comparable water quality while significantly reducing methane emissions.
• Trickling filters offer a sustainable advancement for drinking water treatment from methane-rich groundwaters.