Using AHP Method for Making a Decision on How the Management of Sewage Sludge in the Northern Croatia

Abstract

By 2018, in Croatia, the agglomerations for collecting the sewage and water treatment systems are going to be constructed. All devices will be based on the mechanical-biological method of purification. However, the work of water treatment system produces a problem of sludge management. The paper presents the challenges of wastewater sludge handling and makes a decision on further sludge management. The hierarchical model of the decision making problem by defining the goal, criteria and alternative solutions is developed. On each level of the hierarchical model the elements of the model are compared with each other in pairs, and the preferences are expressed by using the Saaty’s scale. Moreover, the APH model compares the alternative pairs (thermal processing, deposition on agricultural land, disposal to waste repositories and composting) among each others. The intensities and weight preferences of one alternative over another are selected within the required criteria (economic, environmental, organisational and sociological).

Sewage Sludge Thermal Treatment Technology Selection by Utilizing the Analytical Hierarchy Process

“…Technical criteria were considered the least important, assuming that the considered technologies are all technically highly developed and commercially available in Europe but also due to the simplicity and possibility of adaptation of commercial technologies to various conditions [3,13,[50][51][52].…”

“…In order to select the appropriate technology in the case of Rijeka and Croatia, criteria and sub-criteria were chosen based on a literature review of the scientific papers related to laboratory and commercial utilization of incineration, pyrolysis, gasification, and HTC technologies [3,13,[50][51][52]; the situation in Croatia regarding wastewater and sewage sludge management; and expert judgement.…”

Multi-Criteria Decision Analysis to Evaluate Sustainability and Circularity in Agricultural Waste Management

“…This process allows water to be reused in different sectors, such as agriculture. A study by Dušak et al [62] also reused wastewater sludge in northern Croatia, at the regional level, through the storage of treated sludge in landfills, composting with an organic fraction of municipal solid waste and livestock waste, usage in agriculture and forestry, and thermal treatment. Such practices allow for storage, the production of compost, and energy recovery for agricultural uses.…”

“…Alternatively, an MCDA was used for the evaluation of alternative technologies. For instance, an MCDA was used by Lijó et al [7], Illankoon et al [9], Koskiaho et al [13], Bartzas and Komnitsas [14], Kanchanapiya and Tantisattayakul [15], Mishra et al [17], and Dušak et al [62] to evaluate alternative scenarios, technologies, ecotechnologies, and options in general. In terms of the experimental setup of multi-criteria evaluation, the selected methods supported the evaluation in different ways.…”

“…Among these studies, Kanchanapiya and Tantisattayakul [15] did not involve stakeholders; instead, they declared that the use of software and algorithms would avoid subjectivity and biased feedback from participants. Finally, three of the above studies did not specify whether stakeholders and/or experts were actually involved in the applications [4,35,62].…”