Selection and Justification of Preliminary Mechanical Treatment Method of Finely-Dispersed Fraction of Solid Waste Before Disposal

Abstract

Introduction. Every year in Ukraine about 40-50 million tons are dumped in landfills. household waste, of which only no more than 2 million tons are processed and disposed of. To date, more than 15 billion tons of waste have been accumulated in landfills. Insufficient number of official, registered and equipped landfills, lack of modern landfills, as well as insufficient level of waste disposal are the reasons for the emergence of so-called unauthorized landfills, often located within the city. Problem Statement. To date, the processes of utilization of fine fractions of waste, which include the decomposition products of organic waste, remain the least developed. In various methods of waste disposal there are problems when working with large volumes of dispersed waste at almost all stages of their processing. Thus, to increase the efficiency of waste disposal, it is necessary to increase the relative size of the material being processed. This can be done at the stage of preliminary preparation of raw materials. The right choice of pre-treatment method will reduce the negative impact on humans and the environment of harmful elements contained in household waste, as well as increase the efficiency of their disposal Purpose. Carrying out of theoretical and experimental researches of ways of granulation of dispersed fraction and products of disintegration of solid household waste as a stage of their preliminary preparation for utilization. Substantiation on the basis of the received parameters of technology of mechanical processing of waste by various methods of granulation and preparation of the recommendation to a choice of a way of preliminary preparation of dispersed waste for their effective utilization by thermolysis and energy recovery. Carrying out the analysis of ecological danger of formation of dioxins in the course of processing of waste, and also giving practical recommendations concerning their minimization. Materials and methods. As the main stage of preliminary preparation of the dispersed fraction of waste for further processing, three methods of compounding the decomposition products of household waste were considered. Two methods that do not directly affect the particle density - fluidization and granulation in a fluidized bed, as well as pressing. The process of encapsulation of fine waste was studied in an open-type plate granulator; fluidized bed granulation was performed in a laboratory unit-granulator of periodic action with a fluidized bed; compression of dispersed waste was carried out using a screw stamp press with a detachable matrix. Results. Peculiarities of granulation of the dispersed fraction of household waste by different methods have been established. Improving adjustments have been made to the existing developed scheme of thermolysis and energy recovery on the basis of the conducted methods of preliminary preparation of dispersed waste. The economic effect of the introduction of the method of thermolysis and energy recovery of waste into production on the territory of Ukraine, which is planned to be 8 million USD / year, was also calculated. Conclusions. The research results presented in the paper will facilitate the choice of method and means of preliminary preparation of waste for various existing types of their utilization. An experimental method of thermolysis-energy recovery is proposed as an effective method of waste utilization. Adjustments in the existing scheme of TERW on the basis of the conducted researches are planned to essentially increase efficiency of such processing. The ecological danger of formation and emissions of dioxins in the process of thermal processing of waste is considered, as well as practical recommendations for their minimization are given. Key words: solid household waste, decomposition, granulation, thermolysis recovery, dioxins