Use of Sewage Sludge Ash in the Production of Innovative Bricks—An Example of a Circular Economy

Andelina Bubalo, Drazen Vouk, Nina Stirmer and Karlo Nad
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Andelina Bubalo: Water Research Department, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb, Croatia
Drazen Vouk: Water Research Department, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb, Croatia
Nina Stirmer: Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb, Croatia
Karlo Nad: Division of Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb, Croatia

Sustainability, 2021, vol. 13, issue 16, 1-18

Abstract: In this paper the properties of clay bricks with 5 wt%, 10 wt%, and 20 wt% sewage sludge ash (SSA) were studied and compared with the properties of control bricks made of 100% clay. Sewage sludge (SS) was collected at two wastewater treatment plants (WWTPs) in Croatia—WWTP Zagreb and WWTP Karlovac—and incinerated at a temperature of 900 °C The bricks were produced on a laboratory scale. A total of seven types of bricks were produced—control bricks and six types of bricks as combinations of different wt% of SSA generated from SS that was collected at two different WWTPs. The physical and mechanical properties of produced bricks were tested. Compressive strengths of bricks with 5 wt% SSA (54.0–54.5 N/mm 2 ) and 10 wt% SSA (50.2–51.0 N/mm 2 ) were higher compared to the control bricks (50.4 N/mm 2 ), while bricks with 20 wt% SSA (37.0–43.9) N/mm 2 ) had noticeably lower compressive strenght. The coefficient of saturation was lower for bricks with SSA compared to control bricks. The initial absorption values were more pronounced for SSA fractions of 20 wt%.

Keywords: sewage sludge; SSA; bricks; brick production; recycling; circular economy (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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