Treating the Off-Gas from Biogas and Wastewater from WasteWhat are the differences between aerobic and anaerobic digestion, and how do these dif...
Published on by Water Network Research, Official research team of The Water Network
What are the differences between aerobic and anaerobic digestion, and how do these differences influence strategies for pollution control?
Aerobic digestion relies on the presence of sufficient oxygen during digestion and results in high solids production, but low gas yields suitable for fuel. Conversely, anaerobic digestion relies on the absence of available oxygen and produces more usable gas and fewer solids. There are pros/cons to choosing an aerobic or anaerobic system which largely center around the quality of the incoming wastewater and which byproducts are desired (solids vs gas). As previously discussed, the gas derived from anaerobic digestion requires purification, as well as treatment of the off gasses. Both digestion techniques produce wastewater, of different qualities, which may require additional treatment.
What challenges exist when it comes to handling wastewater?
Wastewater from RNG production can be derived from a number of sources. Landfill gas recovered from active landfills may be tied to landfill leachate production. Wastewater from aerobic digestion most likely will require additional secondary treatments to remove contaminants that the biological processes will not consume such as heavy metals, chlorinated compounds or denitrification. Furthermore, methods such as wet scrubbing or adsorption used in RNG purification processes produce wastewater. A notable example is the removal of hydrogen sulfide (H2S) from biogas, a crucial step due to the gas's foul odor and toxicity. Larger RNG operations, therefore, may require a comprehensive treatment train to effectively manage various water contaminants. Additionally, though not specifically a process wastewater issue, some biogas purification methods use chemicals like amines or solvents to clean the biogas. Improper management or disposal of these chemicals can lead to water pollution not directly
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https://www.azocleantech.com/article.aspx?ArticleID=1759Taxonomy
- Biofuels
- Biogas