Advanced Materials Research Vols. 18-19

Abstract: This study presents the experimental results of using admixture of used engine oil and kerosene as an alternative fuel in foundry shops. In this experiment, several proportions of used engine oil (well filtered) and kerosene were measured to make 1000ml per mixture using a calibrated beaker. Each mixture was fired in a furnacensuring atomization, ignition and combustion in a timed set up. Results of the experiment showed that admixtures of 100%, 95% and 90% volume of used engine oil gave low pour point hence were incombustible. 85%, 80% and 75% volume of used engine oil admixtures gave carburized flame. While 55% and below of used engine oil volume of admixtures gave oxygenated flame. 57% - 70% volume of used engine oil admixtures produced neutral flame which is ideal for melting. Of the latter proportions, 70% of used engine oil admixture had the highest heat content 70,780 kj/kg and the lowest cost. Hence this admixture is recommended as an effective admixture for fuel substitution in the foundry shop.

Abstract: The water sector in the last 20 years has undergone radical paradigm shifts arising from the crisis of global proportions that have characterized the sector, prompting many international fora, including the Dublin conference in January 1992. One of the responses from academic institutions to this crisis is the development of computer-based predictive tools for better and more accurate prediction of the variables that affect water use and management. In the School of Civil and Environmental Engineering at the University of the Witwatersrand, attempts have been made to develop software to aid planning, management, and decision making in the water sector. Two of such software are Wadessy - a water distribution network design software, and a groundwater flow modelling software GEMFLOW that is based on the Green element method (GEM). Although their engines are quite robust and have been applied in field studies in Botswana and Zimbabwe, and compare favourably with published models, their elegance in terms of graphical user interface (GUI) is still rudimentary. The cost for their development has been mainly in the training of postgraduate students who have assisted in their development. Industry uptake has been very limited, which is one of the reasons why their GUIs are still rudimentary. With greater investment into the development and marketing of these and many other software, the potential exists to have “made-in-Africa” software with capabilities comparable, if not better than, those developed in more advanced countries. This paper reports on these software, compares these with similar initiatives in more advanced countries, and discusses the challenges in development, funding, and uptake by industry. The experiences described herein are most likely to be similar with other software development initiatives in sub- Saharan Africa.

Abstract: This work focuses on the conception and formulation of appropriate filtration models for use by water treatment professionals for design, development and management of deep-bed (depth) filters. Performance and optimization studies were carried out using data (turbidity, filtration rate, head loss) acquired from pilot filter test runs. The curves developed from these studies were utilized for the formulation of steady-state and hydro-dynamic models of depth filtration. An effluent quality model was developed, relating depth of flow in filter bed with effluent turbidity. This model was verified and validated. The depths obtained are in good agreement with standard values from literature.

Abstract: This paper focus on the use of Carbon dioxide (CO2) instead of sulphuric acid (H2SO4) in a modified wastewater treatment scheme. Over 90% of the vented CO2 from an ammonia plant was used in this scheme, CO2 was directly injected into the wastewater to neutralize it, by reducing the pH to acceptable standard (7.0). This was achieved because the CO2 produces carbonic acid (H2CO3). The use of this process produced a better overall effluent quality of wastewater (pH, 7.56; TDS, 155.15 ppm; Heavy metal, 1.49 ; ppm) as against the use of H2SO4 (pH, 8.77; TDS, 1000 ppm; Heavy metals, 2.90 ppm) which has to be purchased. Savings in operating costs amount to N13,710,600 ($100,813.00) per year, with improved treatment efficiency. Additional long term savings are projected because of reduced shutdown time. However, it was observed that it took 45 minutes longer to achieve this result with CO2.