EFFECTIVE PROCESSING OF DIFFERENT TYPES OF WASTE IN WASTE-TO-ENERGY CENTERS - A CONCRETE EXAMPLE

摘要

This paper deals with a common present problem of complex treatment of waste produced by inhabitants. There are two major types of such waste - municipal solid waste (MSW) and sewage sludge from waste water treatment plants. First, commonly used methods of treatment of these two types of waste are summarized regarding their positive and negative effects. Selected technologies for thermal treatment are further analyzed in terms of specific energy consumption and/or production. A sensitivity analysis of these systems to effective energy utilization is carried out using simulation and operational data from real units. Effect of sludge dewatering during pre-treatment phase on its utilization for energy production as well as effort to improve the energy efficiency of MSW incinerator is demonstrated.Later on, interesting example of future development in this field is presented. An idea about building regional Waste-to-Energy Centers (WTEC) is outlined in a concrete way. Its characteristic features are described in more details. Case study presented in the paper shows how to effectively utilize synergy effects of integrated operation of special incinerator for the thermal treatment of sewage sludge and MSW incineration within WTEC for city of 1 million inhabitants. Waste heat from MSW is effectively utilized for sludge drying which raises its heating value and makes its combustion self-sufficient with regard to additional fuel consumption. Steam produced in the heat recovery systems of both units is led to a single cogeneration system. Finally, environmental and economic benefits as well as constrains of this integrated solution are presented and discussed.