Sustainable Sewage Sludge Management Technologies Selection Based on Techno-Economic-Environmental Criteria: Case Study of Croatia

Abstract

The management and disposal of sewage sludge is becoming a growing concern at the global level. In the past, the main goal was to completely eliminate sewage sludge since it was deemed a threat to humans and the environment, but recently different possibilities for energy generation and material recovery are emerging. Existing technologies such as incineration or direct application in agriculture contribute to quantity reduction and nutrient recovery but are unable to fully exploit the potential of sewage sludge within the frameworks of circular economy and bioeconomy. This paper developed a model within the PROMETHEE method, which analyses technologies for the sustainable management of sewage sludge, which could make the most from it. For the empirical part of the study, the Republic of Croatia was used as a country in which sewage sludge is increasing in quantity as a result of recent upgrades and expansions in the wastewater system. Incineration, gasification, anaerobic digestion, and nutrient recovery were analyzed as treatment concepts for the increased amounts of sewage sludge. The model reveals that the best solution is the material recovery of sewage sludge, using the struvite production pathway through analysis of selected criteria.

Socio-Economic, Technical and Environmental Indicators for Sustainable Sewage Sludge Management and LEAP Analysis of Emissions Reduction

“…One of the manners in which sustainable indicators can be presented is through the LEAP model. Within this paper, a gasification process of sewage sludge is observed with the goal of energy production, using the necessary data presented by Ður dević et al [71], shown in Table 5. The sewage sludge used within the plant is considered to be obtained from the local WWTP for the city of Zagreb-CUPOVZ.…”

“…In scenario S3, which is determined as a realistic potential, sewage sludge has a share of 0.9% and 2% in energy production in 2030 and 2050, respectively (Figure 2). This scenario is based on the current production of sewage sludge in Zagreb, Croatia, which amounts to 20,000 t DM per year [71]. In this scenario, the final energy content of sewage sludge is also considered, not including the energy demand necessary for its preparation.…”

Evaluating the effectiveness of sulfidated nano zerovalent iron and sludge co-application for reducing metal mobility in contaminated soil

“…It is a mixture of water, inorganic and organic materials extracted from various wastewater sources. A significant amount of these sludges is produced globally; in the European Union alone, approximately 11 million tons of these sludges are produced annually 3 , and these sludges must be somehow used or incinerated.…”

Determination of the Self-Ignition Behavior of the Accumulation of Sludge Dust and Sludge Pellets from the Sewage Sludge Thermal Drying Station

“…The increase in interest in biomass utilization has attracted attention to the economic and environmental concerns that arise with biomass storage. The disposal of sewage sludge Energies 2023, 16, 46 2 of 15 may pose problems due to the emission of odor emission, possible risk of pathogenic organisms [7], and hazardous and toxic substances content, including dioxins or heavy metals [8]. The levels of environmental contamination vary geographically.…”

“…Several sewage sludge management strategies include its application in agriculture, wet oxidation, pyrolysis, incineration, and landfilling [7]. Thickening is essential in some processes, including agriculture applications, wet oxidation, or pyrolysis [12].…”