leachate treatment with iron coated peat
LEACHATE TREATMENT WITH IRON COATED PEAT J. KUMPIENE*, A. KASIULIENE* AND I. CARABANTE* * Waste Science and Technology, Luleå University of Technology, Sweden
SUMMARY: Leachates containing variety of organic and inorganic compounds require several treatment steps, including handling of formed sludges or spent sorbents. Organic compounds, as well as several metals (e.g. Cu, Pb), have a high affinity for organic matter, while contaminants present as oxyanions (e.g. As) strongly bind to Fe oxides. The aim of this study was to develop a residue-based sorbent for simultaneous removal of organic and inorganic compounds from aqueous phases, which after the use can be combusted for energy recovery and mass reduction. Peat powder (a residue from peat granulate production) was coated with iron oxides to produce an IronPeat sorbent. Adsorption test with solutions containing trace elements, dissolved humic acids and/or nutrients (P, N) were performed using IronPeat and the peat granulate as control. In majority of cases, IronPeat was a significantly more efficient sorbent for removal of trace elements, phosphates and dissolved carbon than peat granulate. None of the materials are suitable for the removal of nitrates.
1. INTRODUCTION In Sweden due to the industrial activities, such as glass works and wood impregnation, multiple point sources of trace element (TE) contamination are scattered over the country with arsenic (As) being one of the most critical contaminants. Metals, such as copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), and organic contaminants, such as polycyclic aromatic hydrocarbons (PAH), are often co-occurring at such sites. Methods for actual removal of TE from soil are rare or not efficient and excavated soil is mainly relocated for disposal, which does not reduce its ability to release contaminants. Especially challenging is As. Landfill is a low redox environment where As(V) is reduced to a more mobile and toxic As(III) (Corwin et al., 1999) and released due to the reductive dissolution of the main As-bearing phases (Fe-Mn oxides), leading to severalfold increase in As leaching (Kumpiene et al., 2009). Hence, risks for As release to leachate and, if a landfill is not properly constructed, back to groundwater is high. This in turn requires leachate and groundwater treatment. Extensive research efforts have been put into developing techniques for As removal from aqueous phases by sorbents, coagulants, filtration and other methods (Singh et al., 2015; Ungureanu et al., 2015) with several commercial solutions available on the market. Iron (Fe) oxides have a high affinity for As and serve as an effective and potentially inexpensive adsorbent to treat As contaminated water (Carabante et al., 2014). It is common that Fecontaining filters are produced by coating a bulk material, e.g. sand (Devi et al., 2014) or activated carbon (Yürüm et al., 2014), with Fe oxides. Although more expensive, activated carbon has an advantage over sand as it by itself can bind organic and metal contaminants. Proceedings Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium/ 2 - 6 October 2017 S. Margherita di Pula, Cagliari, Italy / © 2017 by CISA Publisher, Italy
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Replacing activated carbon with e.g. peat can lead to a production of a more cost efficient sorbent. The aim of this study was to test a removal efficiency of trace elements, dissolved organic matter and nutrients from aqueous phase by a newly developed iron-peat sorbent (IronPeat) in comparison to a peat granulate sorbent.
2. MATERIALS AND METHODS 2.1 Materials Heat treated peat granulate and peat powder were obtained from Geogen Produktion AB, Sweden. The peat granulate (5-8 mm) is a commercial product used mainly for oil adsorption. The peat powder (
SUMMARY: Leachates containing variety of organic and inorganic compounds require several treatment steps, including handling of formed sludges or spent sorbents. Organic compounds, as well as several metals (e.g. Cu, Pb), have a high affinity for organic matter, while contaminants present as oxyanions (e.g. As) strongly bind to Fe oxides. The aim of this study was to develop a residue-based sorbent for simultaneous removal of organic and inorganic compounds from aqueous phases, which after the use can be combusted for energy recovery and mass reduction. Peat powder (a residue from peat granulate production) was coated with iron oxides to produce an IronPeat sorbent. Adsorption test with solutions containing trace elements, dissolved humic acids and/or nutrients (P, N) were performed using IronPeat and the peat granulate as control. In majority of cases, IronPeat was a significantly more efficient sorbent for removal of trace elements, phosphates and dissolved carbon than peat granulate. None of the materials are suitable for the removal of nitrates.
1. INTRODUCTION In Sweden due to the industrial activities, such as glass works and wood impregnation, multiple point sources of trace element (TE) contamination are scattered over the country with arsenic (As) being one of the most critical contaminants. Metals, such as copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), and organic contaminants, such as polycyclic aromatic hydrocarbons (PAH), are often co-occurring at such sites. Methods for actual removal of TE from soil are rare or not efficient and excavated soil is mainly relocated for disposal, which does not reduce its ability to release contaminants. Especially challenging is As. Landfill is a low redox environment where As(V) is reduced to a more mobile and toxic As(III) (Corwin et al., 1999) and released due to the reductive dissolution of the main As-bearing phases (Fe-Mn oxides), leading to severalfold increase in As leaching (Kumpiene et al., 2009). Hence, risks for As release to leachate and, if a landfill is not properly constructed, back to groundwater is high. This in turn requires leachate and groundwater treatment. Extensive research efforts have been put into developing techniques for As removal from aqueous phases by sorbents, coagulants, filtration and other methods (Singh et al., 2015; Ungureanu et al., 2015) with several commercial solutions available on the market. Iron (Fe) oxides have a high affinity for As and serve as an effective and potentially inexpensive adsorbent to treat As contaminated water (Carabante et al., 2014). It is common that Fecontaining filters are produced by coating a bulk material, e.g. sand (Devi et al., 2014) or activated carbon (Yürüm et al., 2014), with Fe oxides. Although more expensive, activated carbon has an advantage over sand as it by itself can bind organic and metal contaminants. Proceedings Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium/ 2 - 6 October 2017 S. Margherita di Pula, Cagliari, Italy / © 2017 by CISA Publisher, Italy
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Replacing activated carbon with e.g. peat can lead to a production of a more cost efficient sorbent. The aim of this study was to test a removal efficiency of trace elements, dissolved organic matter and nutrients from aqueous phase by a newly developed iron-peat sorbent (IronPeat) in comparison to a peat granulate sorbent.
2. MATERIALS AND METHODS 2.1 Materials Heat treated peat granulate and peat powder were obtained from Geogen Produktion AB, Sweden. The peat granulate (5-8 mm) is a commercial product used mainly for oil adsorption. The peat powder (
