Which of the following is NOT a source of biogas recovery?

Biogas recovery involves the extraction of biogas produced during the anaerobic decomposition of organic materials. Sources such as landfills, livestock operations, and waste treatment plants each contribute significantly to biogas generation.

Landfills generate biogas as the organic waste decomposes anaerobically. This biogas primarily consists of methane and carbon dioxide, making landfills a prominent source for biogas recovery.

Livestock operations produce large amounts of organic waste, particularly from manure, which can be processed in anaerobic digesters to generate biogas. The management of these operations for biogas recovery not only helps in reducing greenhouse gas emissions but also supports energy production.

Waste treatment plants also serve as significant sources due to the breakdown of organic materials found in municipal and industrial wastewater. The anaerobic digestion processes applied in these plants facilitate the conversion of organic content into biogas, which can then be captured and utilized.

In contrast, urban retail outlets do not present a conventional source of biogas recovery. While they might generate some organic waste, the scale and nature of waste produced at retail outlets do not typically lend themselves to efficient biogas production compared to the other sources listed. Hence, urban retail outlets do not serve as a recognized or significant contributor to biogas recovery systems.