UN Sustainable Development Goal 6: Ensure availability and sustainable management of water and sanitation for all
UN Sustainable Development Goal 11: Make cities and human settlements inclusive, safe, resilient and sustainable
How biogas contributes to the above goals:
- Sanitation: As of 2015, of the 7.4 billion population of the world, 2.4 billion people still lack basic sanitation. Anaerobic digestion of biosolids promotes a sanitary and hygienic environment by providing decentralised and local treatment of these wastes. This helps in the prevention of bacterial infections, diarrhoeal diseases like cholera, trachoma, schistosomiasis and hepatitis (UNICEF and WHO, 2015).
- Sludge stabilisation: In the parts of the world where biosolids are collected and treated in waste water treatment plants, anaerobic digestion can be used to stabilise the sludge before being applied as fertilizer to agricultural land. Anaerobic digestion reduces the carbon loading of the water and hence makes the waste water less damaging for the aquatic bodies and life, if discharged. Digestion of solid organic waste and wastewater can make these treatment facilities self-sufficient in terms of economics as well as energy. Where the collection infrastructure is not available, small scale decentralised solutions of treatment are being developed and implemented.
- Landfills: With ever reducing landfill space and the environmental threat it poses to adjoining soil and groundwater, diversion of organic matter from landfills not only offers a way to reduce emissions but is also a responsible waste management strategy. Proper management of organic waste is essential to prevent the spread of diseases like leptospirosis, plague, dengue fever and other bacterial and viral diseases transmitted by mosquitoes, flies, rodents, etc. (Rottier and Ince, 2003)and for improvement of the quality of air in landfill neighbourhoods.
Toilet and Bath complex, Sulabh International, Nasik, India
- Digests excreta collected from 148 toilets used by about 30,000 people everyday
- Electricity produced covers the illumination and water heating needs of the complex
- Operated on a pay-per use basis
- Liberation and rehabilitation of scavengers.
Waste Management–Los Angeles County Sanitation District, California, USA
- Digests primary and secondary wastewater biosolids, urban residential and commercial food waste
- The biogas produced is used to generate electricity and heat for digester and on-site use. The plant is energy neutral on an annual basis.
- The digestate is used for direct land application, composting or landfill daily cover.
- The project was implemented at an existing municipal wastewater digester and can be replicated by other cities