Scenario Analysis for Selecting Sewage Sludge-to-Energy/Matter Recovery Processes

Abstract

The sewage sludges are the byproducts of the wastewater treatment. The new perspective of the wastewater value chain points to a sustainable circular economy approach, where the residual solid material produced by sewage sludge treatments is a resource rather than a waste. A sewage sludge treatment system consists of five main phases; each of them can be performed by different alternative processes. Each process is characterized by its capability to recover energy and/or matter. In this paper, a state of the art of the sludge-to-energy and sludge-to-matter treatments is provided. Then, a scenario analysis is developed to identify suitable sewage sludge treatments plants that best fit the quality and flowrate of sewage sludge to be processed while meeting technological and economic constraints. Based on the scientific literature findings and experts’ opinions, the authors identify a set of reference initial scenarios and the corresponding best treatments’ selection for configuring sewage sludge treatment plants. The scenario analysis reveals a useful reference technical framework when circular economy goals are pursued. The results achieved in all scenarios ensure the potential recovery of matter and/or energy from sewage sludges processes.

Exploiting the Nutrient Potential of Anaerobically Digested Sewage Sludge: A Review

“…Conversion of municipal SS by different thermal processes yields solid residuals (ashes and chars) with significant differences in their composition, values, and qualities [119,120]. Thermal treatments are not applied only to raw SS, but can also be carried out on ADS, providing an energetically favorable treatment cycle, which includes sending the SS to AD to produce biogas and then sending the ADS to thermal treatment [121]. Since the products of thermal processes retain most of the P, N, and K originally contained in the treated sludge, it is possible to use them directly as soil improvers or to further treat them via chemical and thermochemical routes to release the nutrients [3].…”

Turkmenistan’s Gas Sector Development Scenarios Based on Econometric and SWOT Analysis

“…Scenario analysis is often used by scientists and international organizations to forecast the future development of various sectors of the economy and to solve problems of its sustainable development. For example, it has been used in publications concerning: the natural gas market [47][48][49][50], the reduction of greenhouse gas emissions [51][52][53][54][55], waste management [56][57][58], electricity [59], renewable energy [60][61][62], transport [63][64][65] and others [66][67][68].…”

Energy Potential of Biogas from Sewage Sludge after Thermal Hydrolysis and Digestion

“…The process of wastewater treatment (WWT) is inextricably linked with the generation of municipal SS, the processing and management of which represents a major engineering, economic and environmental challenge. The processing of SS, which must be removed from the WWTP, generates up to 50% of the operating costs of the entire WWTP [2]. Among the methods of SS processing that lead to the creation of biogas that can be used for energy production, we can distinguish AD, co-digestion of SS with non-sludge organic wastes, hydrothermal carbonization of SS coupled with AD and pyrolysis [2].…”

“…The processing of SS, which must be removed from the WWTP, generates up to 50% of the operating costs of the entire WWTP [2]. Among the methods of SS processing that lead to the creation of biogas that can be used for energy production, we can distinguish AD, co-digestion of SS with non-sludge organic wastes, hydrothermal carbonization of SS coupled with AD and pyrolysis [2].…”

“…Due to the complexity of WWT and SS processing, it is advisable to support process monitoring and decision making using the latest available technologies. Such a solution has been proposed [2] to choose the most cost-effective methods. SS treatment is mainly carried out in order to reduce the mass and quantity of sludge produced and to stabilize it biologically.…”