On the occasion of World Habitat Day, UN Habitat is calling for ‘waste-wise cities’ that recycle and reuse waste to help realize international agendas, such as the Sustainable Development Goals. But how is that possible for cities in low-income countries that are still struggling to keep their streets and water ways clean? Accra, the capital city of Ghana, leads the way, with public authorities successfully turning city waste into safe and efficient fertilizer for farmers in and around the city.
Waste is piling up in the Greater Accra Metropolitan Area, which is home to about four million people. A typical situation across Africa, and although the amount of waste generated on the continent is relatively low compared to elsewhere, the World Bank expects the volumes to more than double by 2025. Without significant investments in proper management, waste will continue to clog up city streets and drains, creating serious health and environmental challenges.
The problem with collecting all this waste are the immense costs. Waste management is usually the largest cost unit within a municipal budget. Low- and middle-income countries already spend USD 46 billion annually on managing waste and still don’t meet the demand. Struggling to find landfills to dump the waste, city authorities have realized that composting waste can both make a dent in the mounds of waste and generate income through sales. In fact, composting is reducing the organic waste by half, and municipal solid waste is to 60 percent organic. This scenario is starting to prove true in Accra where several waste-to-compost plants have been commissioned over the past years, with more on the way.
New business venture shows success in Ghana
However, making compost purely from organic city waste usually results in a low-quality product. This has served as an impetus to tackle another pressing problem: inadequate sanitation systems. By collecting the contents of public and private septic tanks and pits, you can co-compost nutrient-rich fecal matter with carbon-rich organic city waste, producing a superior and safe organic fertilizer.
Based on years of research, by the CGIAR Research Program on Water, Land and Ecosystems (WLE) and the International Water Management Institute (IWMI), we have helped launch a public-private partnership between the local municipal authority of Tema and a local waste management business, to do just that.
Their new plant, on the outskirts of Accra, has within its first few months transformed 120 metric tonnes of city waste and 2,300 cubic meter of fecal sludge into 110 metric tonnes of high-quality compost. The compost is marketed as FortiferTM and sold to local farmers who are eager to replenish their deprived soils. In this way, the plant aims to break even while the waste volumes will shrink, and with this its transport and disposal costs.
Municipal investments support global goals
Many of the Sustainable Development Goals call for waste recovery and reuse, not least Goal 11: to make growing cities inclusive, safe, resilient and sustainable. But, tapping into circular economy principles and reusing nutrients from waste in agriculture also supports food security goals. When nutrients from waste are added back into starved soils, in the form of compost, farmers in and around cities are better able to feed urban populations.
In addition, recovery and reuse of waste supports climate goals. Currently, greenhouse gas emissions from decaying organic waste accounts for about five percent of the global total. Thus, organic waste reduction and reuse can help mitigate climate change.
Ghana’s nationally determined contributions, which communicate the country’s climate commitments under the Paris Agreement, include ambitions to double the country’s installed capacity for turning waste into compost by 2030. To support the compost market, the Ghanaian government in 2016 included organic fertilizer, including waste-based ones, in its fertilizer subsidy program.
Similar opportunities in cities worldwide
Other countries, like India, went a step further, by urging fertilizer companies to market city compost through their dealer networks. However, for farmers, the impact of normal city compost on the soil would only be visible after two to three years of farming, while a bag of nitrogen fertilizer will have an immediate impact. This is exactly why our researchers started promoting co-composting. It helps to ‘fortify’ the standard waste compost – and its marketing potential.
Currently, researchers are advising authorities and development partners in India, Sri Lanka and other parts of Asia. For example, WLE assisted policy makers in Sri Lanka to include septage management in the country’s sanitation policy. The new policy calls among others for more investment in treating and reusing human waste, including as safe organic fertilizer which opens the door for related investments.
In a recent book, we profile business models based on real-world cases, and these models are ready for municipalities to adopt and expand. While all new initiatives must be customized for specific locations and contexts, some general steps from feasibility studies to the final business plan will help cities get off to the right start.
With such a waste-wise strategy, more cities like Accra can get a head start on converting waste problems into opportunities, solving waste and sanitation challenges and moving towards global goals – all in one go.
Thrive blog is a space for independent thought and aims to stimulate discussion among sustainable agriculture researchers and the public. Blogs are facilitated by the CGIAR Research Program on Water, Land and Ecosystems (WLE) but reflect the opinions and information of the authors only and not necessarily those of WLE and its donors or partners. WLE and partners are supported by CGIAR Trust Fund Contributors, including: ACIAR, DFID, DGIS, SDC, and others.