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S. B. Thakre et al. AB STRACT:Oxidation ditch process is used to treat the municipal and domestic sewage. The untreated sewage generates fouling smell, harmful bacteria, etc. which is hazardous for public health and degrades the environment by librating noxious gases. This paper examines the use of curved blade aerator for oxidation ditch process. The rotor, which controls the aeration, is the main component of the aeration process. Therefore, the objective of this study is to find out the variations in overall oxygen transfer coefficient and aeration efficiency for different configurations of aerators by varying the parameters like speed of aerator, depth of immersion and blade tip angles so as to yield higher values of overall oxygen transfer coefficient and aeration efficiency. Four aerators of different configuration were developed and fabricated in the laboratory and were tested for above mentioned parameters. A mathematical model is developed for predicting the values of k L a and aeration efficiency which has R 2 values of 0.97 and 0.99 for experimentally determined and calculated values. In laboratory studies, the optimum value of overall oxygen transfer coefficient and aeration efficiency were observed to be 10.33/h and 2.269 kg O 2 /kWh for aerator speed of 48 rpm, 5.5 cm depth of immersion and 47 o blade tip angle for curved blade aerator.

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This study investigates the experimental and theoretical impact of biodiesel obtained from hydrodynamic cavitation based waste cooking oil on the performance parameters while testing compression ignition engines. Due to the alarming energy security concerns and inadequacy of fossil fuels, biodiesel is seeking importance globally. Many countries have put forth different subsidies, incentives, and mechanisms, urging the usage of biodiesel. In the current research, nanotechnology is effectively used for enhancement of the blend properties of biodiesel, making them more suitable for compression ignition diesel engines. This investigation includes a comparative analysis of diesel to biodiesel blends with and without the addition of nanoparticles CuO and ZnO. To understand the performance characteristics of a four-stroke diesel engine, a single zone thermodynamic model is developed in it. Comparative readings are taken for the test blends with varying compression ratios of 16, 17, and 18. For each ratio, a variation in the cylinder volume is noted with reference to the rotation in the crank angle. The investigated parameters include net heat release, the rate of pressure rise, brake thermal efficiency, and the heat transfer coefficient. This study concluded that the theoretical results are in close consonance with the experimental results of the comparative analysis of diesel and biodiesel blends. Results obtained from this research paper can contribute to predict combustion process analysis and recommend the effectiveness of nano-additives in biodiesel enhancement.