A technoeconomic analysis of sewage sludge valorization for carbon emission reduction

Abstract

Sewage sludge (SS) is a residual resulting from wastewater treatment that contains both organic and inorganic materials. Nowadays, SS management is a major issue owing to economic considerations and environmental pressure. It has been reported that the current sludge-to-landfill method would pose potential risks to human health and the environment. The incorporation of sustainable sludge valorization techniques (SVTs) into the SS treatment process could be a promising solution by transforming SS into value-added products, which mitigates the environmental impact of SS disposal. However, the selection of the most optimal process pathway from various SVTs is a challenging task. Hence, this paper proposes a mathematical optimization framework to determine the most sustainable SVT pathway using a single objective function of total annualized cost (TAC) minimization with the consideration of carbon pricing. A case study is conducted to evaluate the performance of the optimized SVT pathway compared to the conventional sludge management practice using different SS sources: (1) domestic sewage sludge and (2) a mixture of industrial sludge and domestic SS. The results reveal that the SVT pathway, which includes anaerobic digestion (AD) and followed by land application, is the most ideal route for domestic SS feed. For mixed SS feed, AD followed by landfilling is preferred due to the presence of hazardous constituents in mixed SS. Sensitivity analysis is performed to study the effect of SS quantity and carbon pricing on the SVT selection. It is expected that this study could provide critical insights into the development of a sustainable SS treatment process.

Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats

“…Anaerobic digestion (AD) is a recognised, technologically efficient, economically viable and, therefore, widely used method for the management of sewage sludge (SS). Its use leads to the stabilisation of the SS by reducing the content of organic compounds and susceptibility to putrefaction [1]. AD improves sanitary properties and limits the spread of odours and microbiological aerosols, which determines the possibility of using SS in nature or agriculture [2,3].…”

Evaluation of the Heavy Metals Content in Sewage Sludge from Selected Rural and Urban Wastewater Treatment Plants in Poland in Terms of Its Suitability for Agricultural Use

“…Sewage sludge is a by-product of the wastewater treatment process [3,4]. It is composed of mineral and/or organic compounds and is separated from the liquid phase through sedimentation.…”