Comparative environmental analysis of waste processing methods in paper recycling

Abstract

The paper deals with processing the waste generated in paper recycling: initial waste of paper mill and sludge after wastewater treatment. The authors have analyzed characteristics of the waste of paper recycling generated in paper recycling plant near Kyiv (Ukraine): calorific value, moisture and ash content. The heating value of waste of paper recycling range from 6.5 to 24 kJ/kg and significantly depends on moisture content. Potential environmental impact depends largely on the physical and chemical characteristics of the waste, first of all on humidity and composition. For comparative analysis, investigated waste (a mixture of initial waste of paper mill and sludge, equal weights) has been thermally processed by several existing methods (used in thermal processing of other waste types): incineration in rotary kiln, incineration in grate incinerator and plasma melting. Each equipment had the same minimal gas cleaning system configuration. The environmental performance of waste processing was experimentally identified. The concentrations of the most common pollutants emitted into the air were measured: fine particles (dust), nitrogen oxides, carbon monoxide, sulfur dioxide and hydrogen chloride. Incineration in rotary kiln had over-limit emissions for dust and carbon monoxide, hydrogen chloride concentration was close to the limit. For nitrogen oxides and sulfur dioxide limit excess was not observed. Grate incinerator provided over-limit concentrations for all measured substances except nitrogen oxides. The greatest excess was observed for dust and carbon monoxide (7-8 times). When using plasma melting the authors have measured over-limit concentration only for nitrogen oxides. The data received indicate that regarding to environmental performance the best incineration method for recycling paper waste among those analyzed is plasma melting. Besides, one can assume that minimal gas cleaning system for such incinerators is not enough to capture pollutants effectively.