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

Abstract

Sewage sludge management has gained significance in the last several years, due to its nutrient and energy content. However, technology selection is one of the greater challenges because it is not possible to implement a technology that covers all the requirements of the considered environments. Consequently, this paper shows an example of the utilization of an analytical hierarchy process, as a decision-making tool in terms of technology selection, for sewage sludge management in Rijeka, Croatia. The criteria structuring and evaluation process with the description of several possible alternatives for thermal treatment technologies are defined within this research. For the case of Rijeka, the best and most suitable technology for sewage sludge treatment is gasification, which coincides with the results obtained from the analysis of the literature review. According to the results in this paper, the possibilities of the use of this scientific method on the national level for the selection of sewage sludge treatment technology should be considered, due to the simplicity of its use and capability of its adaptation to various situations and areas.

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

“…Due to a significant reduction of the SS volume, thermal degradation of toxic components, and high energy efficiency, incineration is one of the most applied thermal technologies for SS treatment [122]. During the incineration process, combustible material is oxidized and energy is released as thermal energy in the flue gas, while the organic pollutants, endocrine disruptors, and pathogens contained in SS are destroyed, and volatile HMs, such as quicksilver, are transferred to the flue gas.…”

“…Moreover, compared to the incineration process, which is highly exothermic, pyrolysis is endothermic, of the order of 100 kJ/kg dry solids [133]. This process generates gas and vapors, and liquid (bio-oil and tar) and solid (biochar) products [134] in a ratio which depends on the process parameters [122]. Due to the anoxic conditions, most of the carbon substances (e.g., cellulose, starch, lignin, and glucose) can be hydrolyzed and converted to biochar, with non-vapor elements coexisting [48].…”

The Influence of Sewage Sludge Content and Sintering Temperature on Selected Properties of Lightweight Expanded Clay Aggregate

“…The quadratic model of the multiple regression was used for the adopted rotatable plan [32]: y j = a 0 + a 1 (1) where x 1 is sewage sludge content; x 2 is sintering temperature; a 0 , a 1 , a 2 , a 11 , a 12 , a 12 , and a 22 are coefficients for independent variables estimated with the least-squares method; and y j represents dependent variables representing specific density, apparent density, total porosity, closed porosity, total volume of pores, and water absorption. The significance of coefficients in Equation (1) were verified with an F-test [32]:…”

“…Sewage sludge is an inevitable by-product of municipal wastewater treatment. The amount of sewage sludge generated in the EU is constantly growing, and prognoses indicate the continuation of this trend [ 1 , 2 , 3 ]. Though sewage sludge constitutes only 1–2% of the treated wastewater volume, the cost of its treatment and disposal reaches 60% of the total cost of wastewater treatment plant operations [ 4 ].…”

Redefining Water Treatment: Identification of WWTPs as an Earth System Problem and Circular Economic Eco-Bog System to Challenge It

“…Material Produced from Sewage Sludge ash and Eco-Bog Sedimentations Cement and concrete production from sewage sludge includes incineration of the sludge with an end product of ash to be processed into cement, and of fuel gases. Among the thermal methods of sewage sludge treatment, incineration method is the cheapest when compared with pyrolysis, gasification, and HTC methods [49]. Although the concrete production is recycling with a value addition, valuable fertilizer potential of the sewage sludge is lost in this case.…”