A pilot study tested a new method to treat sewage sludge from a wastewater plant. The team pretreated the sludge before normal anaerobic digestion. The pretreatment produced 200% more renewable natural gas than current practices and reduced the final disposal cost by nearly 50%.
The pretreatment uses high temperature and pressure with a small amount of oxygen. The oxygen helps break long molecules in the sludge. After pretreatment, the researchers used a novel bacterial strain to upgrade the biogas. The bacteria convert carbon dioxide and hydrogen into methane, and the team measured the gas as 99% pure methane. The fuel can replace fossil natural gas and help communities treat waste more sustainably.
Difficult words
- pretreat — do something to material before the main processpretreated
- anaerobic digestion — breakdown by bacteria without oxygen
- renewable natural gas — methane fuel produced from renewable waste
- sludge — thick wet waste from a wastewater plant
- biogas — gas made by bacteria from organic material
- methane — gas produced from carbon dioxide and hydrogen
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Discussion questions
- Would this methane fuel help your community? Why or why not?
- Which part seems most important: the pretreatment or the bacteria upgrade? Explain briefly.
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