Browsing by Author "Wakatuntu, Joel"

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    Development and appraisal of hand wash-wastewater treatment system for water recycling as a resilient response to COVID-19
    (Elsevier, 2021-07-28) Olupot, Peter Wilberforce; Menya, Emmanuel; Jjagwe, Joseph; Wakatuntu, Joel; Kavuma, Tonny; Wabwire, Andrew; Kavuma, Steven; Okodi Mcmondo, Samuel; Nabuuma, Betty; Mpagi Kalibbala, Herbert
    In this work, results from characterization of handwashing wastewater from selected stations in Kampala City, Uganda, revealed that handwashing wastewater did not meet permissible international standards for wastewater discharge to the environment. The ratio of BOD5 to COD of ˂ 0.5 implied that handwashing wastewater was not amenable to biological treatment processes. Turbidity of ˃ 50 NTU pointed to the need for a roughing filter prior to slow sand filtration. Subsequently, a handwashing wastewater treatment system consisting of selected particle sizes of silica sand, zeolite, and granular activated carbon as filtration and/or adsorption media was developed and assessed for performance towards amelioration of the physicochemical and biological parameters of the handwashing wastewater. Treated water from the developed wastewater treatment system exhibited turbidity of 5 NTU, true color of 10 Pt-Co, apparent color of 6 Pt-Co, and TSS of 9 mgL-1, translating to removal efficiencies of up to 98.5%, 98.1%, 99.7%, and 96.9%, respectively. The residual total coliforms and E. coli of 1395 and 1180 CFU(100 mL)-1 respectively, were totally eliminated upon disinfection with 0.5 mL NaOCl (3.5% wt/ vol) per liter of treated wastewater. The treated water was thus suitable for recycling for handwashing purposes as opposed to letting handwashing wastewater merely go down the drain. This approach provides a resilient response to COVID-19, where communities faced with water scarcity can treat and recycle handwashing wastewater at the point of washing. It thus enables more people to have the opportunity to practice handwashing, abating the high risks of infection, which could otherwise arise.
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    Effects of sawdust and adhesive type on the properties of rice husk particleboards
    (Elsevier, 2022-11-17) Olupot, Peter Wilberforce; Menya, Emmanuel; Lubwama, Festo; Ssekaluvu, Lawrence; Nabuuma, Betty; Wakatuntu, Joel
    This study set out to investigate the effects of adhesive type, rice husk and sawdust proportions on the properties of composite particleboards. Specimens of 200 × 200 × 24 mm were made by blending 500 g of rice husks with each adhesive type at a mass ratio of 1:1. The rest of the specimens of similar dimensions were prepared with addition of sawdust in the range of 10–40 wt%, while maintaining the ratio of biomass particles to adhesive at 1:1. Three commercial synthetic adhesives Fevicol (FV), Ponal (PA) and woodfix (WF) were used. The particle adhesive mixtures were molded into a mat which was subsequently cold pressed at 10 MPa and left to dry in air. Density, water absorption (WA), linear expansion (LE), thickness swelling (TS), modulus of elasticity (MOE), modulus of rupture (MOR) and screw holding capacity of the specimens were evaluated. Adhesives were found to have over 42% solid content, with similar liquid constituents but in varying proportions. FTIR library search for the spectra of FV, PA, and WF revealed correlations of 82.5%, 78.6%, and 50.2%, respectively with polyvinyl acetate. The developed boards had a density of 510–610 kg/m3, MOE 13–26 MPa, TS 9–31%, and LE 3–7%. These properties suit them for furniture boards and soundproofing. The properties improved with the increasing proportion of sawdust. FV and PA-bonded particleboards exhibited higher stability and strengths than WF-bonded particleboards due to higher concentrations of polyvinyl-acetate in the latter. Blending 40 wt% sawdust, 10 wt% rice husk with 50 wt% of either FV or PA showed better prospects.
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    Optimization of pyrolysis conditions for production of rice husk-based bio-oil as an energy carrier
    (Elsevier, 2023-11-09) Wakatuntu, Joel; Olupot, Peter Wilberforce; Jjagwe, Joseph; Menya, Emmanuel; Okure, Mackay
    Bio-oil is an eco-friendly energy source with potential to substitute fossil-derived fuels. This study optimized pyrolysis conditions for production of bio-oil from rice husks. Response surface methodology based on central composite design was employed to maximize bio-oil yield and high heating value (HHV) while minimizing water and ash contents. The pyrolysis process conditions were; temperature (400–650 ◦C), heating rate (6000–9750 ◦Ch-1), and holding time (600–1800 s). Analysis of variance revealed that the linear model best fits the responses of bio-oil yield and water content. On the other hand, the quadratic model best fits the responses of HHV and ash content. Pyrolysis temperature had the greatest influence on each of the studied responses, followed by holding time and lastly heating rate. Optimum pyrolysis conditions were found to be; temperature (650 ◦C), heating rate (9750 ◦Ch-1), and holding time (1800 s), leading to bio-oil yield, HHV, water, and ash contents of 38.13%, 23.40 MJ/kg, 18.27%db, and 0.16%db, respectively. These results fall in the range of standard quality values for bio-oil in published literature where >15 MJ/kg, 20–30%, 0.15–0.25% are the recommended ranges for HHV, water, and ash contents, respectively. Results from the FTIR spectroscopy revealed that phenolic compounds contributed the most to bio-oil composition. Phenolic compounds positively influenced the quality of bio-oil due to their high calorific values. Gas chromatograph and mass spectrometry results showed peaks continuing to spill up to the maximum retention time indicating good thermal stability and bio-oil quality.
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    Optimization of roughing filtration unit for a handwashing wastewater recirculation point-of-use system
    (IWA PUBLISHING COMAPANY, 2022-11-22) Olupot, Peter Wilberforce; Menya, Emmanuel; Jjagwe, Joseph; Wakatuntu, Joel; Román, Franz; Hensel, Oliver
    A downward roughing filter unit consisting of silica sand as the filter medium was optimized for performance towards removal of turbidity and suspended solids from handwashing wastewater. Design-Expert software was employed to optimize media particle size, filter depth, and flow rate. Linear and quadratic models were found to best fit the responses of turbidity and suspended solids removal, respectively. Particle size and flow rate were the only parameters with significant effects on the removal of turbidity and suspended solids. Optimal conditions were found to be media particle size 0.6 mm, filter depth 12 cm, and flow rate 0.3 Lmin 1 , corresponding to removal efficiencies of 62 and 67% for turbidity and total suspended solids (TSS), respectively, as predicted by the model. Validation of the model at optimal conditions resulted in turbidity and TSS removal of 55 and 53%, respectively. Additionally, removal efficiencies of the roughing filter towards apparent colour, true colour, biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) from handwashing wastewater were 56, 20,32, and 5%,respectively. Overall, although the turbidity of filtered water was .50 NTU, the reduction achieved by roughing filtration is a significant step in enhancing the performance of water treatment processes downstream, including filtration and adsorption by slow sand filters and activated carbon, respectively.