scholarly journals The Immobilisation of Heavy Metals from Sewage Sludge Ash in CO2-Cured Mortars

2021 ◽  
Vol 13 (22) ◽  
pp. 12893
Author(s):  
Erick Grünhäuser Soares ◽  
João Castro-Gomes ◽  
Mateusz Sitarz ◽  
Tomasz Zdeb ◽  
Izabela Hager

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.

2020 ◽  
Vol 322 ◽  
pp. 01026
Author(s):  
Mateusz Sitarz ◽  
Tomasz Zdeb ◽  
João Castro Gomes ◽  
Erick Grünhäuser Soares ◽  
Izabela Hager

Sewage sludge is a semi-solid waste material created as a result of the sewage treatment of industrial or municipal wastewater. Because the laws and regulations of the European Union require not only a reduction in waste generation but also the preparation of waste for reuse and disposal, it is necessary to look for new methods of the application of sewage sludge as part of sustainable waste management. In this study, ash formed as a result of the combustion of sewage sludge from the sewage treatment plant in Płaszów, Krakow in a fluidised bed furnace at a temperature of around 800°C was used. Sewage sludge ash (SSA) contains over 30% SiO2 and approx. 10% Al2O3, which indicates potential applications in geopolymer materials. In this study, samples of geopolymer mortars with a binder containing sewage sludge ash as well as fly ash (FA) and ground granulated blast furnace slag (GGBFS) were prepared. The mechanical parameters were determined after 2, 7, 14, and 28 days. The results show that the sewage sludge ash-based geopolymer shows binding properties at ambient temperature and, depending on the presence of FA and/or GGBFS, the compressive strength varies from 5 to 45 MPa after 28 days. The aim of the research was also to determine the total content of heavy metals (Sb, As, Cr, Cd, Cu, Ni, Pb, Hg, Zn) in the raw materials used and their leachability from the structure of the hardened materials. Immobilisation of heavy metals is very promising. Based on the results of tests, it seems possible to use SSA in geopolymer materials, but not as the main component of the binder.


2018 ◽  
Vol 347 ◽  
pp. 227-232 ◽  
Author(s):  
Rundong Li ◽  
Zhenyu Zhai ◽  
Yanlong Li ◽  
Tianhua Yang ◽  
Yang Chen

2014 ◽  
Vol 49 (12) ◽  
pp. 1910-1920 ◽  
Author(s):  
Lisbeth M. Ottosen ◽  
Pernille E. Jensen ◽  
Gunvor M. Kirkelund

2021 ◽  
Vol 10 (6) ◽  
pp. e25910615736
Author(s):  
João Victor da Cunha Oliveira ◽  
Leila Soares Viegas Barreto Chagas ◽  
Frankslale Fabian Diniz de Andrade Meira ◽  
Arnaldo Manoel Pereira Carneiro

Through environmental policies that provide a gradual discussion about the destination of the tailings produced in the most diverse industrial sectors, the sewage sludge is emphasized by the problematic destination arising from the amount of toxic compounds that compose it, compromising its disposal. Aiming to fulfill the sustainable role through the creation of mechanisms that favor the ecological coexistence between environment and human beings, it is possible through the use of construction materials, considered as conventional, the use of calcined sewage sludge as an enhancer of the properties of matrix materials cement, significantly improving its performance against mechanical stresses and degradation mechanisms. Based on the need to implement measures to mitigate environmental impacts through the production of eco-efficient materials, the ashes of sanitary sewage sludge as a partial substitute for Portland cement have now been used as an input in coating mortars. This substitution focuses on reducing the large volume of sludge generated by the Sewage Treatment Plants, as well as on the reduction in the consumption of cement, a large CO2 generator during its manufacturing process. It was observed that through the use of this calcined by-product applied in mortars, a relevant physical-mechanical performance in cementitious materials is ratified, that in comparison to the material without the use of it, better results are observed, resulting from the reactivity conferred to the sludge after the thermal degradation process, making it a pozzolana.


2008 ◽  
Vol 57 (5) ◽  
pp. 707-714 ◽  
Author(s):  
C. Niewersch ◽  
C. N. Koh ◽  
T. Wintgens ◽  
T. Melin ◽  
C. Schaum ◽  
...  

Due to the depletion of mineral phosphorus resources there is an increasing demand for efficient phosphorus recovery technologies. In this study the potential of nanofiltration to recover phosphorus from pre-treated sewage sludge is investigated. The efficiency of three commercial nanofiltration membranes (Desal 5DK, NP030; MPF34) was tested using model solutions. Desal 5DK showed the best selectivity for phosphorus. A pH of lower than 1.5 was found to be most suitable. Desal 5DK was used on four different sewage sludge ash eluates and on one sewage sludge. In these experiments it was shown that a separation of phosphorus from undesired components such as heavy metals was possible with significant variations in the efficiency for the different ash and sludge types. Additionally the achievable product recovery was investigated with model solutions. A product recovery of 57.1% was attained for pH 1 and 41.4% for pH 1.5.


2020 ◽  
Vol 12 (16) ◽  
pp. 6517 ◽  
Author(s):  
Jolanta Latosińska ◽  
Przemysław Czapik

Popular incineration of sewage sludge results in the increase in heavy metals content in ash. The knowledge of the total content of heavy metals in sewage sludge ash does not demonstrate a potential hazard. The toxicity of heavy metals in great measure depends on the form of their occurrence. The prevailing norms do not require the ecological risk assessment of the environmental burden with heavy metals for the choice of the method of the utilization of sewage sludge ash. The paper presents the research results on the mobility of heavy metals in sewage sludge ash after its incineration. The geo-accumulation index (IGAI), the potential ecological risk index (PERI) and the risk assessment code (RAC) were used for the evaluation of the potential soil contamination with heavy metals. The authors also suggested a new formula, which took into consideration more factors influencing the risk of the contamination of a water-soil environment with heavy metals—the water and soil environment risk index (WSERI). The calculated indices for sewage sludge ash indicate the risk of soil contamination with heavy metals.


Chemosphere ◽  
2015 ◽  
Vol 125 ◽  
pp. 122-129 ◽  
Author(s):  
Benjamin Ebbers ◽  
Lisbeth M. Ottosen ◽  
Pernille E. Jensen

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