Waste to energy, indispensable cornerstone for circular economy: A mini-review

Abstract

This mini-review aims at proving that waste-to-energy (WtE) is an essential cornerstone for circular economy (CE). Based on literature, the history of thermal waste treatment over the last 150 years is investigated, from open burning to WtE with resource recovery and final sink function. The results show that in the past incineration solved the issues it was designed for but often created new and sometimes even worse problems: The introduction of incineration in the 19th century improved urban sanitation, decreased waste volume and prolonged operational life of landfills. But it also polluted the environment, triggering an unprecedented scientific and engineering effort of all stakeholders. Today, WtE is one of the best investigated and optimized technologies in waste management. It enables the recovery of energy as heat and electric power and facilitates the ‘cleaning’ of cycles by the destruction of hazardous organic substances. Recent developments in resource recovery from WtE residues allow to recycle metals and, in the case of sewage sludge, even phosphorus by thermal recycling. Combined with carbon capture and storage technology, WtE stands for a quantifiable contribution to greenhouse gas reduction. Today, WtE is indispensable to reach the goals of CE, namely recycling of energy and materials, supplying safe final sinks for persistent organic substances and minimizing the need for sinks for hazardous inorganic substances.

Sorption of Iodine on Biochar Derived from the Processing of Urban Sludge and Garden Waste at Different Pyrolysis Temperatures

“…As of 2020, the annual production of urban sludge is estimated to exceed 60 million tons [3,4]. To address the environmental issues associated with urban sludge, technology in the use of sludge resources has emerged, aiming to reduce environmental risks and generate multiple benefits by recycling and reusing valuable substances in sludge [4][5][6]. Currently, the recycling and reusing rate of sludge treatment in China is approximately 33% nationwide, which is relatively low compared to some areas with high human development [2,7,8].…”

Sustainable synergistic approach to chemolithotrophs—supported bioremediation of wastewater and flue gas

“…Agricultural, industrial, and municipal liquid waste effluents can be investigated as low-cost growing media for chemolithotrophs. Adding these sources and the flue gas can be an advantage for the proliferation of chemolithotrophs by making an abundance of nutrients available 17 . Besides being ecologically benign, cost-effective, and sustainable, the treatment process should consider the origin and composition of flue gas and wastewater 4 .…”