Browsing by Author "Chacha, Nyangi"

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    A comparative study of the adhesive effects of cassava peels, banana peels, and potato peels on the durability of briquettes made from coconut husk charcoal
    (AIP Advances, 2025-05-14) Mng’onya, Angel; Moirana, Ruth; Maagi, Mtaki; Chacha, Nyangi
    Over-dependency on traditional energy sources, particularly in African countries, significantly contributes to deforestation and carbon emis- sions. Agricultural waste presents a suitable alternative to conventional energy through bio-briquettes; however, they are underutilized. This study evaluated bio-briquettes’ mechanical properties, including abrasion resistance, impact resistance, and water penetration resistance, made from carbonized coconut husks using cassava peels, banana peels, and potato peels as binders. Briquettes bound with potato peels had the highest impact resistance of 96.55%, 96.43%, and 95.26% for ratios 80:20, 70:30, and 60:40, respectively. In comparison, cassava peel-bound briquettes exhibited moderate impact resistance, increasing to 87.71% at a 60:40 ratio. In contrast, banana peel binders had the lower impact resistance, with a maximum impact resistance of 76.72%. Abrasion resistance followed the same trend; in briquettes bound with potato peel, abrasion resistance increased up to 88.69% at 60:40, while banana peels performed the least effectively; the abrasion resistance was 70.09% at 60:40 ratio. Water penetration resistance improved with the increase in binder concentration, with potato peel-bound briquettes reach- ing 79.82% at 60:40, while cassava and banana peel-bound briquettes showed complete disintegration at an 80:20 ratio. Overall, this study indicates that agricultural waste functions as an efficient binder in briquette production, supporting sustainable household energy use. This study contributes to renewable energy innovation, waste valorization, and climate change mitigation by promoting sustainable alternatives to traditional biomass energy.
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    Evaluating the performance of faecal sludge dewatering technologies in urban settings of developing African countries: a review
    (Taylor & Francis online, 2024-05-02) Mwamlima, Petro; Njau, Karoli N.; Rwiza, Mwemezi; Chacha, Nyangi
    Inadequate dewatering technologies are reported as the dominant challenge in handling faecal sludge (FS) within urban settings of most African countries. Studies have been carried out to evaluate the efficiencies of unplanted sand drying beds (USDBs), decentralized wastewater treatment systems (DEWATS), and geo-tubes. However, limited information is available on comparative capabilities in dewatering the FS. This work reviewed treatment efficiencies by assessing the reported actual waste removal capacities and ascertaining if they align with the design removal provisions. Peer-reviewed papers, books, and technical reports from trusted sources were examined. The results show that all the technologies perform best in dewatering the FS; however, USDBs are widely adopted for city-wide treatment, and the other two are suited for decentralized communities. The USDB is challenged by frequent clogging and poor quality of dewatered sludge when reused or recycled in the production of solid fuel and compost due to sticking sand after sludge harvesting. The DEWATS and geo-tubes increase operational costs when used to treat the FS at a large scale. More studies should be conducted to explore locally made, cost-effective filter media and technologies to enhance the dewatering quality and quantity of the FS and increase the quality of recycled by-products.