Evaluation of Waste Blends with Sewage Sludge as a Potential Material Input for Pyrolysis

Abstract

In line with the requirements of the circular economy, the European Union’s waste management legislative changes also concern the treatment of sewage sludge. Although sewage sludge production cannot be prevented, its quantities may be reduced by the synergetic effect of energy recovery via choosing a proper technology. Sewage sludge is difficult to apply as fuel alone, because of its high moisture and ash content. However, its energy use will be increased by adding suitable waste materials (different types of plastics, waste tires and paper rejects). Most recently, the thermal utilization of sewage sludge via incineration or pyrolysis has grown in importance. This article describes the fuel parameters of particular waste materials and of their blends with sewage sludge in connection with laboratory-scale thermal decomposition in an inert atmosphere, for their potential use in a semi-pilot plant pyrolysis unit. For pyrolytic application, the results of thermogravimetric analysis are needed in order to know the maximal temperature of thermal decomposition in an inert atmosphere, maximal mass losses, and weight loss rates. The samples of different thermoplastics mixed with sewage sludge, and low-density polyethylene blends with sewage sludge, had the lowest residual masses (70–74%) and the highest weight loss rates (11–19%/min). On the other hand, the blend of polyester rejects from tire processing, paper rejects and sewage sludge had the second highest residual mass (60%) and the lowest weight loss rate (3%/min).

Analysis of Ash Melting Temperatures of Agricultural Pellets Detected during Different Conditions

“…The development of energy-efficient technology and the shift to nonfossil energy sources, such as renewable energy sources, are expected and appear to be very promising [1,2]. Except, huge amounts of waste are produced by consumer society, and their disposal can negatively impact human health and ecosystems [3,4]. Agricultural residues can be used as fuels due to their energy potential and also the emission reduction compared to fossil fuels.…”

Pyrolysis of Specific Non-Recyclable Waste Materials: Energy Recovery and Detailed Product Characteristics

“…This laboratory pyrolysis unit consists of a reactor with a fixed grate that is heated by an electric spiral around the jacket. In our previous work [49], we focused on the comprehensive characterization of selected waste materials and tested various waste materials. The analyses provided very specific data regarding the modeling and optimization of the pyrolytic process, and therefore, we set the reactor temperature to 600 • C. As a result, we can expect higher-quality pyrolytic products.…”

Influence of Valorization of Sewage Sludge on Energy Consumption in the Drying Process

“…The phenomenon of sludge "sticking" is beneficial in the proposed solution by facilitating the formation of the final product in the form of briquettes and increasing their compactness and durability. Kubonova et al [45] showed that sewage sludge is a very suitable binder for individual components of the alternative fuel, at the same time indicating that the moisture content of sewage sludge (about 72 wt.%) was an advantage for mixing with other types of waste.…”