RESUMEN
This paper investigates the five different gas emissions during the firing process of clay bricks and bricks incorporating biosolids. In this study, three different biosolids produced at the Western Treatment Plant and Eastern Treatment Plant, Melbourne, were used as an alternative raw material to the conventional brick soil to produce bricks. Three sets of bricks were manufactured incorporating 25% of biosolids by weight. Initially, three biosolids samples and brick soil were characterised by their chemical and mineral compositions, organic content and particle size distribution. Brick samples were fired in a tube furnace at a temperature of 1050⯰C for three hours. Five different gas emissions - SO2, CO2, NO, CO, and HCN - were measured at different temperatures throughout the firing process. The results indicated that all the gas emissions were increased with the addition of biosolids. The energy input and production based factors were developed based on the experimental results, which were then used in the life cycle assessment of biosolids-amended bricks. The cradle-to-gate results of life cycle assessment revealed that the production of biosolids bricks reduced environmental impacts for all impact categories except water depletion impact when compared to conventional bricks.
Asunto(s)
Materiales de Construcción , Administración de Residuos , SueloRESUMEN
The substantial increase in biosolids production throughout the world requires sustainable routes for reuse. This study describes the leaching behaviour of potentially hazardous metals from the green and fired bricks incorporating four different biosolids samples from the Eastern treatment plant (ETP) and Western treatment plant (WTP) in Melbourne. The biosolids samples were characterized by XRD, XRF, TGA, particle size distribution, and organic content. The leaching of As, Ag, Ba, Be, Cd, Cr, Cu, Mo, Ni, Pb, Sb, Se, and Zn was evaluated for both the green and the fired bricks according to the Toxicity characteristic leaching procedure (TCLP) and the Australian bottle leaching procedure (ABLP). The leaching of heavy metals from both the green and the fired bricks was compared to investigate the effect of firing on the leaching capability of bricks. The results showed that the leaching of heavy metals from fired bricks was significantly lower than that for the green bricks. The ABLP concentrations of heavy metals were higher than those found using the TCLP method, mainly due to the higher specific surface area of the particles used in the ABLP method. Moreover, bricks were evaluated by the technological properties, such as compressive strength, density and water absorption.