Recent Advancement in Commercial and Other Sustainable Techniques for Energy and Material Recovery from Sewage Sludge

Abstract

Rapid population growth and urbanization have resulted in a multi-fold increase in water consumption over the last few decades, resulting in the generation of large amounts of sewage and sewage sludge that impose severe environmental burdens if not handled properly. Sludge management itself accounts for up to 50% of the total operating costs of wastewater treatment plants (WWTPs). Conventional sludge management practices such as incineration, landfilling, and ocean disposal have been deemed difficult in light of today’s stringent environmental legislation and compliance standards. As a result, progress has been made toward developing more sustainable approaches for sludge management. This study reviews recent advancements in sewage sludge management techniques that not only ensure the safe disposal of sewage sludge but also focus on utilizing the potential of sewage sludge as feedstock for energy and resource recovery. Energy could be recovered by subjecting the pre-treated sludge to controlled anaerobic digestion (AD) to produce biogas or by utilizing the lipid content of the sewage sludge through esterification or direct sludge pyrolysis to produce biodiesel/bio-oil. Heavy metals such as Ag, Au, Cu, Fe, Ga, Cr, and others, as well as nutrients such as N, P, K, Mg, S, and others, could also be recovered. If energy and resource recovery from sewage sludge is practiced on a global scale, it could significantly contribute to global greenhouse gas (GHG) emission reduction. This review discusses the commercially developed and still-under-research technologies for energy and other resource recovery of sewage sludge. Additionally, techniques, along with their limitations and potential measures to improve their yields, are also discussed.

Critical assessment and recommendations for sewage sludge management in Poland

“…Sewage sludge can also be a source of secondary raw materials (Smol & Szołdrowska, 2021). Research on the recycling and recovery of raw materials from sewage waste focuses on technologies such as biogas recovery (Siddiqui et al, 2023;Paranjpe et al, 2020), biological recovery of phosphorus and nitrogen (Boniardi et al, 2022;Saoudi et al, 2022), thermal recovery, metal recovery and the production of fertilisers from sewage sludge (Kominko et al, 2019). The aim of these studies is to reduce the amount of waste that goes to landfills and to obtain added value from raw materials derived from sewage sludge (You et al, 2021).…”

Enhanced Recovery of Alginate-like Extracellular Polymers (ALE) from Waste-Activated Sludge Using Sodium Percarbonate: Performance and Characteristics

“…Over the last few decades, the global production of waste-activated sludge (WAS) has been continuously increasing, which poses a potential threat to the environment [1]. According to the statistics, China produces 60 million tons of sewage sludge (80% water content) with an annually increasing rate of 10%, while the European Union produces approximately 50 million tons of sewage sludge per year and the United States produces 40 million tons [2]. With growing global urbanization and increasingly stringent regulations on sludge reuse or disposal, it prompts us to reevaluate the current sludge management strategies.…”