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Solid fuelization technology can increase the heating value of sewage sludge such that it can be utilised as a fossil fuel substitutes. Reducing landfilling of bottom and fly ash resulting from heavy metals contained in sewage sludge is challenging. Hence, combustion melting technology (CMT), which can discharge bottom ash in the form of slag, has been proposed herein as an alternative to the conventional incineration technology. However, further research is required to improve the flowability of slag. Applicability of CMT for the stable treatment of heavy metals in the ash generated during the energisation of sewage sludge solid fuel has been reviewed. The change in the degree of fluidity was identified via a laboratory-scale fluidity measurement experiment following changes in melting temperature, mixing ratio of sewage sludge and sawdust, and basicity. The pouring index (PI) of sewage sludge solid fuel (pellet) was maintained at a level of about 60% at a basicity index of 0.8. Based on the results, the slagging rates and volume reduction rates, exhaust gas analysis, and heavy metal elution characteristics under oxygen enrichment were derived from a 2 ton/day combustion melting pilot plant experiment; thereafter, the feasibility of combustion melting of sewage sludge solid fuel was determined.

Asbestos is a human carcinogen that causes diseases, such as lung cancer and malignant mesothelioma. In Korea, approximately 1.23 × 109 kg of asbestos raw materials was imported for about 30 years. More than 80% of this were used as building material, such as interior materials and ceiling materials. Among the manufactured asbestos-containing materials, the closest product to the human body is asbestos-tex, used as ceiling material. In this study, asbestos contained in asbestos-tex was transformed into a shape that is physically safe for the human body through mineral carbonation and the results were verified through the analysis of airborne asbestos concentrations. We found that asbestos-tex powder in a buffer solution at 100 °C and at partial CO2 pressures of greater than 10 MPa transformed its constituent chrysotile asbestos moiety ((Mg3Si2O5(OH)4) into magnesite (MgCO3). Consequently, the needle-shaped asbestos fibers (diameters ≤ 3 µm) were converted to an angular rod-shaped mineral (diameters > 5 µm) that is safe for humans.

Distribution system loss reduction has been grossly neglected by most electricity utilities even though it contributes to no less than 75 per cent of the total system losses. Existing methods of loss reduction involve enormous capital cost and extensive rehabilitation to the existing distribution reticulation and are hence not very practical, compounded with the problem of coping with the high and dynamic load growth in most developing countries. The paper looks into techniques of selecting and operating the distribution system, with minimum or no physical change in the present distribution reticulation to reduce losses. It proposes that the existing distribution network be operated in 'island groups' by paralleling selected feeders into an island 'c' IEE, 1995 Paper 2lOOC (P9), first received 21st October 1994 and in revised form