The study aimed at biochar production from maize cob and its performance in improving water physiochemical attributes. Three feedstock masses (2, 2.5, 3 kg) were used for biochar production. Nine treatment combinations of T1L1, T1L2, T1L3, T2L1, T2L2, T2L3, T3L1, T3L2 and T3L3 in triplicate were used for biochar performance. Biochar yield of 50% was averagely achieved at slow pyrolysis conditions (300 to 600°C) and 120 min residence time. Biochar had 4.13% moisture content, 6.86% ash, 17.70% volatile matter, 71.28% fixed carbon, and a pH of 10.27. Odour, colour, and total hardness of the wastewater improved after filtration using biochar to acceptable levels for potable water use. Total hardness reduced by 51.9% in T2L2 and 44.4% in T3L2. Findings front maize cob biochar as a purification technology for domestic potable water use. There is need for maize cob biochar performance on heavy metals and when it is sandwiched with other materials.

Traditional grain cleaning methods are labor-intensive, time-consuming, and yet very inefficient. The use of available mechanical seed cleaners is widely limited since they are expensive to own, operate, and maintain. A Pedal Operated Seed Cleaner (PoS-Cleaner) was developed and its performance evaluated. Appropriate engineering principles and methodologies were used in the sizing and construction of the machine. The cleaner consists of a bicycle-like pedaling system, hopper, a centrifugal fan, and three cleaning sieves which include two inside interlocking sieves (one sieve fixed and the other adjustable); whose meshes can be adjusted to be larger than the size of the unclean seeds by longitudinally translating the second sieve to achieve the appropriate seed size. This allows trapping of impurities larger than the seeds. Cleaning rates of 576.5 kg/h, 375.8 kg/h, and 377.4 kg/h for maize, beans, and groundnuts were obtained respectively. Maize, beans, and groundnuts had their highest cleaning efficiencies of 95.09%, 87.61%, and 81.67% at inner sieve sizes of 13 mm, 16 mm and 10 mm respectively, pedaling speed of 60 rpm. The PoS-Cleaner presents a more viable cleaning option for smallholder farmers in rural and remote areas with no access to the national grid, therefore producing high-quality seeds. This will eventually facilitate agricultural value addition and increase individual family incomes in Uganda. Article highlights A pedal operated multi-seed cleaner was developed. Achieved 5 times higher seed cleaning rates compared to traditional cleaning technologies. Attained higher separation efficiencies of seed and externalities compared to traditional technologies.

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