Air quality monitoring from open waste and incinerator burning in Cape Maclear, Malawi

Waste management in Cape Maclear, Malawi, is a critical issue due to the lack of formal collection services and reliance on open waste burning. This paper details improvements to two De Montfort Mark 8A incinerators and evaluates their impact on combustion efficiency and emissions reduction. Key engineering upgrades included larger chimneys, additional air vents, structural reinforcements, a chimney cap, and the integration of a heat exchanger system. As a result, combustion temperatures increased from 663°C to 846°C at the Billy Riordan Memorial Clinic and from 372°C to 907°C at the waste deposit (managed by the NGO Sustainable Cape Maclear). The waste-to-ashes ratio also improved significantly, decreasing from 22.14% to 10.17% at the clinic and from 39.44% to 17.11% at the waste deposit, indicating more complete combustion. To optimize waste handling, a sorting table and forklift were introduced for efficient separation of non-combustible materials, while a dedicated ash pit ensured safer disposal. Air quality monitoring showed a drastic reduction in PM1.0, PM2.5, and PM10 emissions, with concentrations falling below WHO guidelines, greatly improving local air quality. Additionally, this paper presents the first-ever integration of a heat exchanger system onto a De Montfort Mark 8A incinerator. This system utilizes waste heat to generate warm water without additional fuel or labor. All data, CAD files, and code related to the project have been made openly available on GitHub (Bahisson et al., 2025), offering a replicable framework for similar waste management initiatives in other low-resource settings. These findings demonstrate how targeted engineering improvements can make small-scale incineration systems more efficient and environmentally sustainable, offering valuable insights for similar waste management initiatives.