Browsing by Author "Sanka, Paulo"

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Application of rice and corn husk biochar for removal of heavy metal ions from industrial wastewater
(NM-AIST, 2020-01) Sanka, Paulo
This study investigated the removal of heavy metal ions from industrial wastewater by using rice and corn husk biochar. The choice of the materials was influenced by their largest surface area, plentiful functional groups and their availability in the local environment. Rice and corn husks were pyrolysed at 500, 600, and 700 °C to make biochars that were used to treat low quality industrial wastewater. Carbonisation of rice husks at 600 °C produced the best removal efficiencies for Cr (65%), Fe (90%) and Pb (> 90%). The carbonisation of corn husks at 600 °C produced the worst removal efficiencies for Cr (only 20%) and Pb (slightly > 35%). Regardless of the carbonisation temperature, rice husk biochars performed better than corn husk biochars. All data fitted well in both the Langmuir and Freundlich isotherm models (R 2 values ranging between 0.82 and 0.99). The Langmuir separation factor RL was had negative values; probably due to the low initial concentration of the adsorbates in the raw wastewater. All the biochars showed a relatively short contact time (20 to 30 min) to attain maximum adsorption efficiencies – a promising feature for future industrial applications. The studied biochar materials from rice and corn husk have the potential to remove heavy metal ions from industrial wastewater; rice husk biochar showed higher removal capacity than corn husk.
Production of low emission briquettes from carbonized faecal sludge as an alternative source of cooking energy
(Springer Nature, 2024) Sanka, Paulo; Germain, Olivier; Khalifa, Leyla; Komakech, Hans; Magambo, Hezron
Abstract Background In Tanzania, firewood, charcoal, and agricultural waste play a crucial role in daily life as sources of cooking energy, especially in rural areas. Using these energy sources contributes to deforestation and the emis- sion of harmful substances, leading to health problems. This study highlights the potential of faecal sludge bri- quettes as an innovative, environmentally friendly, and sustainable alternative to traditional energy sources to meet the increasing demand for cooking energy in Tanzania. The process involved sludge characterization, drying, sorting, carbonization, milling, briquette making, and characterization. Results A study was conducted to assess the presence of zinc (Zn), cadmium (Cd), and lead (Pb) in faecal sludge collected from households. The results indicates that the levels of these metals were all within the acceptable limits set by the Tanzanian Standards (TZS) for sludge disposal and use in the environment, which are 5.00 mg/L, 5.00 mg/L, and 30.00 mg/L, respectively. Septic tanks and pit latrines sludge had a concentration of 0.5 mg/L and 0.5 mg/L for Zn, 0.55 mg/L, and 0.6 mg/L for Cd, and 10.01 mg/L and 4.87 mg/L for Pb, respectively. Adding 75% charcoal dust improved the gross and net heating values from 10.47 and 10.16 to 19.29 and 18.86 MJ/kg, respectively. Similarly, add- ing 50% charcoal dust improved the gross and net heating values to 19.24 and 18.78 MJ/kg. The emission of particu- late matter (micrograms/m3 ) was reduced from 30.4 and 35 to 10.3 and 11.8 for PM2.5 and 7 and 8 for PM10, while car- bon monoxide emission decreased from 51.2 to 19.7 ppm. Conclusion The results strongly suggest that briquettes made of carbonized faecal sludge mixed with other biomass materials could offer an alternative to traditional solid fuels, with the added benefits of reducing greenhouse gas emissions, deforestation, and longer burning times.
Removal of Selected Heavy Metal Ions from Industrial Wastewater Using Rice and Corn Husk Biochar
(Springer Nature Switzerland AG., 2020-05-12) Sanka, Paulo; Rwiza, Mwemezi; Mtei, Kelvin
This study investigated the removal of heavy metal ions from industrial wastewater by using rice and corn husk biochar. The choice of the materials was influenced by their large surface area, abundance of functional groups as well as their availability in the local environment. Rice and corn husks were pyrolyzed at 500, 600, and 700 °C to make biochars that were used to treat low-quality industrial wastewater. Initial metal ion levels in wastewater and residual levels after the application of biochars were measured using an atomic adsorption spectrophotometer. Carbonization of rice husks at 600 °C produced the best removal efficiencies for Cr (65%), Fe (90%), and Pb (> 90%). The carbonization of corn husks at 600 °C produced the worst removal efficiencies for Cr (only 20%) and Pb (slightly > 35%). Regardless of the carbonization temperature, rice husk biochars performed better than corn husk biochars. Experimental data fitted well the Langmuir and Freundlich isotherm models (R2 values ranging between 0.82 and 0.99). The Langmuir separation factor, RL, had negative values, probably due to the low initial concentration of the adsorbates in the raw wastewater. All the biochars showed a relatively short contact time (20 to 30 min) to attain maximum adsorption efficiencies and are a promising feature for future industrial applications. The studied biochar materials from rice and corn husk have the potential to remove heavy metal ions from industrial wastewater; rice husk biochar showed higher removal capacity than corn husk biochars.