Composting is a growing global concern for cities who face increasing waste generation and the associated climate impact, especially in developing countries where, even if consumption habits are changing, organic matters still represent more than 50 % of the domestic solid wastes. Here are the usually expected benefits from compositing municipal organic waste in cities.
- Public hygiene in the suburbs: the organic matters contribute to diseases spreading and cause a significant loss of amenity (odors, rodent, etc) in the public space if they are not regularly collected (especially in hot and wet conditions)
- Municipal solid waste management system: composting can cut the quantities of waste to be landfilled and the environmental impacts associated with it (gas emissions, odors, leachate). It requires less investment and operational capacity that anaerobic digestion. Indirectly, separating the organic matters from other waste will make the sorting of other recyclables much easier and more efficient.
- Agricultural production system: as soil conditioner and “slow” fertilizer, compost has a real potential to reduce the needs for chemicals and contribute to soil conservation (and thus to restore soil fertility on the long term). Typically, one kilogram of compost per square meter is distributed annually to farmlands.
- Carbon emission: Composting is a carbon neutral natural degradation process, which helps storing carbon in soil. By diverting organic matters from landfills, it decreases methane emissions in proportion. Therefore, composting systems are eligible for carbon credit, but this seems rather difficult. in 2012, only 46 projects were receiving, under the Clean Development Mechanism.
Sustainable Synergies 