Material Recovery as a Strategy for Landfill Remediation

A Case Study of Nkolfoulou Landfill, Cameroon


Introduction

With rapid urbanization and population growth, the world faces an increasing challenge in solid waste management. The total amount of waste generated globally reached 2.01 billion tons in 2016 and is expected to surge by 70% by 2050. This article, written by Ateh Suh Nkwekeu Ndiforngu, Roberto Raga, Abdou Nasser Njoya Mfokou, Paula Ngo Fin Tan and Gergino Yemele Chounna, introduces and explores how, in developing countries, ineffective waste management is a pressing issue, often consuming 20%–50% of municipal budgets. Cameroon, like many other nations, struggles with waste disposal, with most waste ending up in landfills due to a lack of proper waste segregation and recycling policies.


The Nkolfoulou Landfill, located in Yaoundé, Cameroon, serves as the city’s primary waste disposal site. However, its current waste treatment strategies are inefficientandenvironmentally hazardous. Material recovery is emerging as a viable solution to address these issues. This strategy involves retrieving and reusing valuable materials from both fresh and old waste to reduce landfill volume, improve resource sustainability, and minimize environmental pollution.


Understanding the Nkolfoulou Landfill

The Nkolfoulou landfill spans 56 hectares and is located 16 km from Yaoundé city center. Managed by HYSACAM (Cameroon Urban Hygiene and Sanitation), the landfill receives approximately 1,400 tons of waste daily, ranking it as the second-highest waste disposal site in Cameroon. However, due to the absence of waste separation centers, a significant amount of recyclable and reusable materials are buried, rather than being processed for further use.


The landfill is situated near the Mfoulou River, which raises concerns about leachate contamination. Despite efforts to manage waste, gas emissions and environmental degradation remain major challenges. The landfill’s design includes gas extraction wells, but maintenance issues have led to inefficiencies in capturing methane emissions, contributing to air pollution and climate change. The lack of a structured recycling system exacerbates these problems, as valuable materials that could be repurposed are instead buried under layers of waste.


Landfills like Nkolfoulou not only contribute to greenhouse gas emissions but also pose serious risks to public health and biodiversity. Uncontrolled methane emissions can lead to spontaneous fires, which worsen air pollution and release toxic fumes. Additionally, leachate seepage into water sources can cause contamination, making nearby water supplies unsafe for human consumption.


Waste Characterization and Recovery Potential

A waste characterization study was conducted in six districts of Yaoundé. Fresh waste was classified into eight categories, including organic waste, plastics, metals, paper, glass, textiles, and hazardous waste. The results showed that organic waste (putrescible material) comprised 57% of the total waste. Plastics accounted for 14%, an increase from previous years, despite government efforts to ban non-biodegradable plastic bags. Paper and cardboard made up 9%, while textiles, including diapers and sanitary pads, accounted for 13%. Metals and glass represented only 1% each, primarily due to informal recycling efforts by waste pickers.


For landfill-mined waste (old waste excavated from older landfill sections), a reduction in organic waste content was observed due to decomposition. However, plastics, metals, and glass remained largely intact, highlighting their potential for recovery. Excavated waste is often more compact and contaminated, making processing more expensive but still viable with proper treatment and separation techniques.


Studies in other developing countries suggest that material recovery programs can significantly reduce landfill reliance. In Kenya and India, pilot projects integrating waste sorting at source have successfully improved recycling rates, demonstrating that strategic interventions can transform waste management systems.


Benefits of Material Recovery

One of the significant advantages of material recovery is the potential to extend the landfill’s lifespan by reclaiming airspace. Fresh waste recovery resulted in a 29.2% airspace gain per hectare. Landfill mining yielded a 19% recovery rate, making previously buried land reusable. The estimated airspace reclaimed from old waste was 317,459 m³, allowing for more effective landfill management.


Recovering valuable materials also reduces the demand for virgin resources, decreasing reliance on raw material extraction. By reintegrating recyclables such as metals, plastics, and glass into the economy, cities can lower production costs for industries while simultaneously reducing environmental damage caused by mining and raw material processing.


Material recovery presents substantial economic benefits, especially for plastics, metals, and glass. If properly managed, revenue generation from waste mining could be significantly increased. Plastics recovery could generate up to $398,125 per month. Metal recovery could bring in approximately $51,694 per month. Glass recovery could yield $68,925 per month. Reclaimed landfill space could save the municipality an additional $50,000 per hectare.


Additionally, integrating organic waste composting into landfill management strategies could provide an alternative source of fertilizer for agriculture, benefiting local farmers and promoting sustainable agricultural practices. Composting reduces landfill methane emissions while simultaneously enriching soil health, making it a win-win strategy for both waste management and food production.


Challenges and Limitations

Despite its potential, material recovery in Nkolfoulou faces several barriers. Lack of waste segregation at the source makes recovery less efficient. High contamination levels in old waste require additional processing before materials can be recycled. Limited infrastructure and technology for sorting, processing, and marketing recovered materials pose another challenge. Health and safety risks for informal waste pickers due to exposure to hazardous waste remain a major concern.


Another significant limitation is the high cost of landfill mining and waste processing. Many developing countries lack the financial resources to invest in large-scale waste recovery operations. Moreover, without proper government policies and incentives, private investors are reluctant to fund waste management projects.


Public perception and behavior also play a critical role. Without education and awareness campaigns, households and businesses continue to dispose of waste improperly, making material recovery more difficult and expensive. Implementing policies that encourage responsible waste disposal and incentivize recycling can help mitigate these issues.


The Future of Waste Management in Cameroon

To improve waste management and material recovery, Cameroon needs to implement structured policies that promote waste segregation at the household level to enhance recovery efficiency. Investment in recycling facilities is necessary to process plastics, metals, and organic waste. Formalization of the waste-picking sector would provide safety measures and fair wages for workers. Public awareness campaigns should educate citizens on the importance of waste reduction and recycling.


Developing public-private partnerships could accelerate investment in waste processing infrastructure, creating jobs and fostering economic growth. Implementing a circular economy model, where waste materials are continuously repurposed, will ensure that resources are maximally utilized, reducing dependency on new raw materials.


The government could introduce tax incentives and subsidies for companies investing in recycling and waste recovery. Additionally, integrating waste-to-energy technology, such as biogas production from organic waste, can provide a sustainable source of renewable energy for local communities.


Additional considerations

A crucial aspect of landfill remediation through material recovery is the development of a circular economy, where waste is not merely discarded but continuously repurposed to generate new value. Many successful waste management models worldwide emphasize the importance of integrating informal waste collectors into formalized systems, ensuring that they receive fair wages and protective equipment while contributing significantly to recycling efforts.


In countries like Brazil and India, waste-pickers’ cooperatives have improved recycling rates while enhancing social equity. Implementing similar programs in Cameroon could help bridge the gap between informal waste recovery and industrial-scale recycling, ensuring a steady supply of recovered materials while improving working conditions for waste pickers. Another key factor is technological investment, including the establishment of automated sorting facilities that can process large volumes of waste efficiently.


Currently, manual sorting is labor-intensive and limits the scale of material recovery operations. Introducing mechanized sorting technologies, such as optical scanners and magnetic separators, would drastically improve efficiency, allowing for the extraction of a higher percentage of recyclable materials from both fresh and mined waste. Moreover, local industries need incentives to use recycled materials. Government policies that mandate a minimum percentage of recycled content in new products could boost demand for recovered waste materials, ensuring that recycling remains economically viable. By aligning landfill remediation strategies with national economic policies, Cameroon can create a sustainable waste-to-value chain, fostering both environmental sustainability and economic growth.


Conclusion

Material recovery is a practical and profitable strategy for improving landfill management in Cameroon and other developing nations. By focusing on fresh waste recovery before landfilling and strategic landfill mining, cities can extend landfill lifespans, reduce environmental pollution, and generate economic value. If material recovery is prioritized, Cameroon can transition from waste accumulation to resource optimization, setting an example for other developing nations. With proper investment and strategic planning, the Nkolfoulou landfill could become a model for sustainable waste management in Africa.


This text is an excerpt from an article published under the following reference: Ndiforngu, A.S.N., Raga, R., Mfokou, A.N.N. et al. Material recovery as a strategy for landfill remediation: a case study of Nkolfoulou landfill, Cameroon. J Mater Cycles Waste Manag (2025). https://doi.org/10.1007/s10163-025-02157-z. Want to learn more about the circular economy and its issues? Visit Tondo’s blog!

Ateh Ndiforngu

Ateh Ndiforngu is a PhD student at the Department of Civil, Environmental and Architectural Engineering in the University of Padova. Prior to this, she worked on innovative landfill rehabilitation techniques that promote circular economy principles for her Master's degree through a joint program between the National Advanced School of Public Works in Yaoundé and the University of Padova, hence... Read more

Ateh Ndiforngu is a PhD student at the Department of Civil, Environmental and Architectural Engineering in the University of Padova. Prior to this, she worked on innovative landfill rehabilitation techniques that promote circular economy principles for her Master's degree through a joint program between the National Advanced School of Public Works in Yaoundé and the University of Padova, hence the subsequent published article on “material recovery as a strategy for landfill remediation.”

Building on her knowledge of circular economy principles and as required of her doctoral research, she is currently studying the topic of “Waste and Health,”with a focus on the fate of microplastics and their impact on ecosystems and human health. Having a strong interest in connecting scientific research with innovative solutions, she aims to contribute to the development of sustainable policies and technologies that foster a more circular and resilient economy.

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