Friday, December 1, 2023

Urban forestry and biofuel: Complementary strategy for urban sustainability


India is thriving to adopt greener fuel solutions like the rest of the world. Biofuel is one of them that can be an alternative solution to petrol or diesel. Urban waste is a problem in every city but it can be turned into a fuel and energy solution through proper strategy.

Rapid urbanization in the present world has created a number of environmental issues like vehicular pollution, loss of green cover, depletion of aquifer level and others. A major problem is the generation and disposal of urban wastes which has become a major threat to the environment. According to the World Urbanization Prospects, 2018, the percentage of the world population living in urban areas has increased from 30% in 1950 to 55% in 2018 and is estimated to become 68% by 2050.

Though North America and Europe constitute the most urbanized regions in the world, it is estimated that three countries of the developing world, India, China and Nigeria are going to account for 35% of the growth in urban population between 2018 and 2050. Thus urban sustainability is a prime concern for the world in general and for the developing countries in particular.

An increase in urban population, improvement in the standard of living, increase in the number of nuclear families, change in lifestyle have all contributed to a proliferation in the amount of waste generated in the cities. This huge quantity of waste affects the environment, health and also has socio-economic implications in the long term as a large area of land is wasted for landfill purposes. Segregation of urban waste and recycling through bio-gas and electricity production and composting can solve multiple issues arising from urban wastes.

The large landfill areas can be converted into forestry while biogas (CNG) produced from waste can be used for low-pollution mobility and electricity generation for street lighting. The by-product of the biogas plant can be used as fertilizers for forestry and agriculture. Both forestry and pollution-free mobility can lead to better air quality.

A case study conducted by this author on possible economic, social and environmental implications of a complementary strategy of urban forestry and biofuel production reveals that such a project has immense social and environmental benefits and economic benefits can also be reaped if taken up on a larger scale. The current discussion is centred around the case study based on New Town, the satellite city of Kolkata, the state capital of West Bengal, in the eastern part of India.

Disposal of solid waste: environmental hazard

A serious environmental issue arises in the eastern part of Kolkata due to the dumping of solid waste in the ecologically vulnerable East Kolkata Wetlands (EKW). The solid wastes from three urban areas, Bidhannagar (under Bidhannagar Municipal Corporation), Nabadiganta (under Nabadiganta Industrial Township Authority) and New Town (under Newtown Kolkata Development Authority) are dumped at MollarBheri, a fishery lying in the EKW.

Bheri is a term in local parlance that means shallow, flat-bottomed fishery. MollarBheri like other bheris in EKW is a waste-water fed fishery. EKW is listed as a wetland of international importance by the Ramsar convention. It is the world’s largest waste-water-fed aquaculture system that is often termed as the ‘kidney’ of Kolkata as it naturally treats the city’s wastewater. Spread over an area of 12,500 hectares, this wetland conducts an important function of natural purification of the city’s sewage through agriculture and pisciculture.

A Calcutta High Court order of 1990 and the Wetlands Act 2016 prohibit any change of land use to protect EKW from pollution.

A Calcutta High Court order of 1990 and the Wetlands Act 2016 prohibit any change of land use to protect EKW from pollution. But rapid urbanization in the adjoining areas has led to the doubling of wastes in the last 15 years. The leachate from the garbage dump tends to pollute the water bodies, endangering the existence of the water body and the livelihood of the fishermen and farmers in this area.

The National Green Tribunal (NGT), a statutory body in India that handles cases related to environmental disputes and protection of forests, has recently fined the urban local bodies (ULB) responsible for dumping garbage and threatening the environment in the wetlands. The NGT has ordered the ULBs to cordon off the area and to also conduct biomining projects to remove the legacy wastes from this area.

Biomining can help in using part of the garbage to generate Refuse Derived Fuel and the rest for composting.

Biomining can help in using part of the garbage to generate Refuse Derived Fuel and the rest for composting. But to do this waste segregation is a primary requirement to make the compost free of heavy metals and other hazardous components. Segregation of biodegradable and non-biodegradable wastes at source and using the non-bio wastes for recycling and energy generation and using bio-wastes for composting can effectively prevent the formation of garbage dumps that threaten delicate ecosystems like the EKW.

Waste management initiatives in New Town

New Town, situated in North 24 Parganas district of West Bengal covers an area of 35.5 sq km, with a population of 1500,000. NKDA is the civic body founded in 2008 entrusted with the responsibility of providing civic services and amenities to the township. The NKDA has introduced the practice of solid waste segregation in March 2019 by launching campaigns to make the residents aware of waste segregation.

The NKDA has also come up with plans of setting up biogas plants that convert kitchen wastes to fuels like Compressed Natural Gas (CNG) and also composting units to convert wastes into composts that can be used in the township for greening projects. A biogas plant has become operational in New Town in February 2021, that converts 5 tonnes of organic waste to CNG every day.

Biogas and urban forestry: Exploring the complementary strategies

At the backdrop of the waste management initiatives in New Town we have analysed the possibility of introducing a complementary strategy – generation of fuel and electricity from biowastes and using the compost and biochar for urban forestry that can solve a plethora of urban environmental problems. While the solid wastes are recycled, reused for energy production and composting, the landfills can be converted to urban forests.

This can be a self-sustaining process as the compost produced from wastes can be used for forestry, the non-bio waste can be recycled and the fuel generated from biogas plants can be utilized for street lighting and running vehicles, saving fuel costs and providing clean energy.

The Nagar Van scheme announced by the government of India in June 2020 has set up a target of setting up 200 urban forests in a five years’ period, across the country with the involvement of the Forest Departments, NGOs, Municipal bodies and local people. The Panchayat and Rural Development department of the Government of West Bengal has taken up a scheme to set up forests by the Miyawaki method at different parts of the state.

The Miyawaki method is a Japanese technique that envisages the planting of native species of trees in a designated area to produce dense forests that require maintenance only in the first three years.

The Miyawaki method is a Japanese technique that envisages the planting of native species of trees in a designated area to produce dense forests that require maintenance only in the first three years. This technique has been adopted in Shyampur, located in the neighbouring district of Howrah, from 2019 to develop a forest in a 1000m2 area. This is taken as a model in this study to understand the cost and benefits of urban forestry especially by replacing landfills.

Landfills are the easiest and cheapest way of waste disposal but have become a cause of severe environmental hazard in recent times as the leachate tends to contaminate water bodies and generates harmful gases that pollute the atmosphere. But these landfills can be utilized for harnessing environmental and economic benefits by initiating methane capture technique for generating fuel and applying the revegetation technique to regulate leachate generation. This method of treating landfills can produce a number of social, economic and environmental benefits by way of improved air quality, reduced groundwater contamination and improving biodiversity by creating a natural eco-system.

Urban agriculture and forestry may involve risks if untreated waste-water and solid wastes containing heavy metals contaminate the soil and thereby enter the food chain.

Urban agriculture and forestry may involve risks if untreated waste-water and solid wastes containing heavy metals contaminate the soil and thereby enter the food chain. With proper waste segregation and treatment, this risk can be avoided. Such a venture is worth taking as urban forestry and agriculture provide myriad benefits that include poverty alleviation, food security, provision of ecosystem services, mitigating effects of climate change along with protection from storms, prevention of erosion, recharge of the water table and such others.

Using urban solid waste in the production of energy and manure through composting and biochar production can effectively reduce the piling up of garbage dump on landfills and free up the landfill areas for urban forestry for a cleaner environment.


Way forward

A composite project of urban solid waste management, fuel production, compost generation and conversion of the landfill to forest has a number of important environmental, social and economic benefits. Even viewed from the criteria of economic costs and benefits this project is expected to generate net benefits considering fuel production and forestry together.

The multicriteria based cost-benefit analysis of the complementary strategy that we conducted on New Town yields high environmental and social scores indicating major environmental and social benefits. Economic returns are low since the project is at the initial stage and it is to be seen what kind of economic returns can be obtained from the project. A public-private partnership model of executing the project can lead to effective waste segregation, a technically efficient way of fuel generation and a socially and environmentally sound way of maintaining urban forestry.

A positive economic score indicates that the project will provide economic returns and can be attractive for the private sector to take this up in partnering with the public organization. Moreover, at the initial stages, average capital costs are high which is likely to come down with time. Since both the strategies have returned in terms of social welfare and environmental benefits it is worth making the public investment as well.

Also Read: Solar energy: Your rooftop can be the first step to a clean environment

(Debalina Saha is faculty of Economics, Centre for Excellence in Public Management (Civil Services Study Centre), Administrative Training Institute, Kolkata.)

(Disclaimer: The views expressed in the article above are those of the authors’ and do not necessarily represent or reflect the views of Unless otherwise noted, the author is writing in his/her personal capacity. They are not intended and should not be thought to represent official ideas, attitudes, or policies of any agency or institution.)


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