Abstract
Sewage treatment processes are a serious environmental threat due to the difficulties involved in its waste management and disposal. Therefore, one developing trend in sewage sludge processing is its thermal treatment, which generates sewage sludge ash that may contain many environmental pollutants, such as heavy metals. Moreover, due to the European Union requirements that not only focus on the waste generation reduction but also on its reuse and final disposal, it is essential to pursue new applications of such resources, such as the waste-based material incorporation into alternative cementitious materials. Thus, this study evaluated the heavy metals leachability of CO2-cured mortars incorporating sewage sludge ash as filler. For this purpose, Portland cement, reactive magnesia, and electric arc furnace slag were used to produce three different CO2-cured mortars, which were cured though pressurised accelerated carbonation curing for 24h. These mortars presented up to 12.7 MPa as compressive strength and their carbonation was confirmed by TG-DTG and FT-IR analyses. Their leachability of heavy metals met the European requirements for all waste materials, including inert materials, and post-industrial wastewater. Therefore, the immobilisation of heavy metals in this binding technology may be considered an effective method to safely manage sewage sludge ash.
Highlights
The construction materials industry, which was once based on a wide range of materials appropriate to local conditions and/or to specific needs, has evolved into an industry based on Portland cement-based materials [1]
The CO2 -reactive compounds consist of Portland cement (PC) containing a limestone additive provided by Secil under the trade name CEM II/B-L 32.5N and reactive magnesium oxide (r-MgO), known under the trade name “Magal P”, provided by Invivo-nSA, which is, calcinated magnesia mainly used as an additive to animal feed
The results show that every mix composition presented a loss of mass after the room conditions (RC) period, none presented changes in their dimensions and the bulk density was reduced
Summary
The construction materials industry, which was once based on a wide range of materials appropriate to local conditions and/or to specific needs, has evolved into an industry based on Portland cement-based materials [1]. Such a change of trend has turned Portland cement-based materials into the most heavily consumed manufactured material in the world in terms of volume, being responsible for about 7% of the total anthropogenic emissions of carbon dioxide (CO2 ) [2]. It was shown to be practicable to use waste materials in CRMC-based materials [8,9,10,11,12] which may reduce the environmental impacts and production cost of the designed materials [13].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
