Conceptualising "zero-waste city" in the context of Bangladesh

A consumption-driven society produces a large amount of waste. This massive amount of waste puts enormous pressures on management of city waste effectively. Waste management is a priority area in city governance. City waste management is crucial for sustainable development. It is also required for achieving Sustainable Development Goals (SDGs) as SDG 11 deals with solid waste management in a sustainable manner. But the city planning process in Bangladesh is yet to focus on modern waste management conforming with the SDGs. 

Designing sustainable cities is a very challenging task, especially when it has to conform to the SDGs. In densely mega cities like Dhaka, large amounts of daily waste create a huge impact on city life. For example, the recent water-logging of Dhaka city has been observed as a partial consequence of the poor city waste management. Moreover, the present waste management system is not suitable for tackling global climate change and its effects on human life are accelerated through generation of global greenhouse gas (GHG) emissions, landfill methane (CH4), emissions of carbon dioxide (CO2) resulted from waste containing fossil carbon (plastic or synthetic textiles). The concept of "zero-waste city" is to deal with the GHG issue with provision for sustainable waste management and emission reduction. 

A visionary approach to "zero-waste city" is very difficult to achieve. Zero-waste cities should recycle 100 per cent of their total waste (mainly solid) generated, or improve all possible resources from a waste flow and generate no harmful waste to our environment. 

CHALLENGES IN TURNING CITIES INTO ZERO-WASTE ONES: Rapid increase in urban waste tests existing management capacity. According to the World Bank prediction for Bangladesh, the country will generate 47,000 tons of urban waste daily in 2025, which is about three times higher compared with the present amount. At present, municipal authorities struggle to collect even 50 per cent of waste. Therefore, a huge amount of waste lies scattered in different places, e.g., open drains, on roadsides and in low-lying areas. These contribute to water trapping, detrimental odour and environmental pollution. 

 City managements should be dynamic and combine a holistic approach to different complex issues. Core features of such an integrated approach are: 1) the process of managing or recycling waste should be affordable in the socio-economic context, 2) regulatory in the socio-political context, 3) applicable in the context of technological aspects, 4) efficient or effective in the context of technology and economy (return on investment), and 5) finally, all of these aspects should ensure environmental sustainability of a city. 

Our efforts should go into retrofitting of existing building fabric, infrastructures and communities in parallel with developing new ones. We should develop sustainable designs inspired by nature, where waste is considered a resource (fertiliser, fuel, energy, etc.), and fabricate new building materials from recycled waste.

We should plan to generate energy from all possible renewable energy sources - solar, wind, biomass, geothermal, etc. We can modify the way we produce energy and introduce more and more decentralised systems on frontages and roofs, where cities themselves turn into power stations and all the residents become potential energy producers and suppliers instead of just being consumers.

We can develop zero-waste cities by applying 3R (Reduce, Reuse and Recycle) strategy of waste management by 1) collecting 100 per cent waste of a city, 2) recycling 100 per cent for resource recovery, and 3) ensuring sustainable consumption and production.

FIVE KEY PRINCIPLES FOR ZERO-WASTE CITIES: We should rethink design, production, maintenance/operation, recycling, buildings, neighbourhoods, and the overall infrastructure of a city. An integrated model of a design strategy is based on five interconnected principles. The principles are: 

1. Behaviour change and sustainable consumption (performing with more education, training and research on global climate change, sustainable development goals or any other relevant development agenda).

2. Extended producer and consumer responsibility (producers and consumers' responsibility must be ensured through managing the impact of the totality of a product of both producer and consumer)

3. 100 per cent recycling of municipal solid waste (performing with 100 per cent collection of all types of waste from various source points, establishing methods of waste segregation and disposal at household level, on roadsides or any other source points)

4. Legislated zero landfill and incineration (building awareness of greenhouse gas emissions and global warming)

5. 100 per cent resource recovery from waste (performing with the 3R strategy, sustainable consumption, innovative product design, and a 100 per cent conversion of waste disposal for decomposition; even landfill and incineration process may achieve a 100 per cent waste recovery primarily, but the solution is not sustainable for the long term. Since about 70 per cent of our total city waste is food and vegetables, decomposition may be an important method for maximum waste recovery).

In most of the world cities, the modern development paradigm is based on an increased trend of sustainable resource consumption. Consumers need to realise that the waste is a worthy resource. For instance, food waste, glass, e-waste, packaging cardboard or others have a value. Legislation is needed in the market-based waste management process where a whole product life-cycle process needs to be integrated. For example, open dumping and straightforward landfills are a common action for solid waste management in Bangladesh. This is possibly happening due to ignorance of waste value, low investment and operation costs. A major portion of our city waste is organic (about 70 per cent), which remains mostly uncollected, unutilised and unmanaged, or not properly managed. As a result, this unmanaged organic waste is a source of many health hazards and creates environmental problems for most cities and towns of Bangladesh. 

The government has, however, initiated a 3R (Reduce, Reuse and Recycle) pilot project aimed at reducing the impact of greenhouse gases in Dhaka and Chittagong. We need to scale up such types of projects in more cities. 

The writer is a senior research associate and sustainability professional at BRAC Research and Evaluation Division. [email protected]