PRODUCTION AND EXPERIMENTAL EVALUATION OF BIOFUELS BASED ON SEWAGE SLUDGE FOR HEAT ENERGY AND BUILDING MATERIALS

Abstract

In the article considered approaches to the thermal utilization of municipal waste in terms of sewage sludge and obtaining combustion products that can be used as construction material. The generation of bio-waste in the form of sewage sludge has reached the volume of 5 billion tons today and continues to accumulate on sludge sites of municipal sewage treatment plants. This condition creates an environmental hazard and is a serious problem that requires an urgent solution. By applying thermochemical processing of sewage sludge as fuel at industrial and communal enterprises, it is possible to obtain heat energy and ash waste, which can be used as an aggregate in asphalt-concrete and ordinary building mixtures with mineral binders. In the course of the research, biofuel was obtained in the form of pellets, for the production of which the sediments of municipal wastewater and coniferous sawdust were used as raw materials, as waste from their mechanical processing. The main thermotechnical characteristics of the pellets were established experimentally: density, ash content and heat of combustion. The results showed that the mixture of sewage sludge and sawdust during pressing allows the production of dense (above 1.0 g/cm3) and high-calorie pellets with a heat of combustion above 18.0 MJ/kg even at relatively low pressures (> 130 MPa). The ash residues obtained during combustion are not stable, they are easily destroyed with the transition to a heterodisperse state and are suitable for use as a building material. The use of this method of disposal of sewage sludge will allow solving the problems of resource conservation, energy efficiency and environmental protection in a complex way: dispose of sewage sludge, reduce the cost of construction products and reduce the costs of natural raw materials and fuel and energy resources.