| Title: | Sulphur compounds removal from an industrial landfill leachate by catalytic oxidation and chemical precipitation: From a hazardous effluent to a value-added product |
| Author(s): | Barbosa Segundo ID; Silva T; Moreira FC; Silva GV; Boaventura RAR; Vilar VJP; |
| Address: | "Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: tania.silva@fe.up.pt. INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal. Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: vilar@fe.up.pt" |
| DOI: | 10.1016/j.scitotenv.2018.11.274 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "This study focused on the removal of sulphur compounds from a high-strength leachate of a hazardous industrial waste landfill. Firstly, sulphides (0.5?ª+g?ª+L(-1)) and sulphites (2.5?ª+g?ª+L(-1)) were catalytic oxidised at natural pH (8.7). Air or H(2)O(2) were applied as oxidants and metals present in the leachate were used as catalysts. Distinct air flow rates and H(2)O(2):sulphur molar ratios were tested. Concentrations of sulphide and sulphite lower than 1.0?ª+mg?ª+L(-1) (emission limit value - ELV) were obtained after 5-h oxygenation or 1-min peroxidation under the best conditions, i.e. air flow rate of 1 L(air) L(leachate)(-1)?ª+min(-1) and H(2)O(2):sulphur stoichiometric ratio. Aeration was considered unsafe since >33 volatile organic compounds (VOCs) and hydrogen sulphide (H(2)S) were released to the atmosphere. Thus, only the H(2)O(2)-oxidised leachate pursued treatment. Sulphates (13?ª+g?ª+L(-1)) were removed by chemical precipitation as ettringite or barite applying different reactants contents and pH values. Without pH correction, sulphate contents below 2.0?ª+g?ª+L(-1) (ELV) were achieved using a [Ca(2+)]:[Al(3+)]:[SO(4)(2-)] molar ratio of 12:4:3 (2-fold stoichiometry) and a [Ba(2+)]:[SO(4)(2-)] molar ratio of 1.0:1.0 (1-fold stoichiometry). The analysis of precipitates by X-ray diffraction (XRD) showed a three-phase ettringite (only 67% corresponding to ettringite itself) and single-phase barite. Barite precipitation proved to be more appealing since a value-added product was obtained and, furthermore, less reactants were required. After sulphur compounds removal using H(2)O(2)-driven catalytic oxidation and chemical precipitation through barite, the leachate was suitable for biological treatment, despite the high salinity, and a high fraction of the organic load (46%) could be biologically oxidised" |
| Keywords: | Catalytic oxidation Chemical precipitation Commercial-value product Hazardous industrial waste landfill Sulphur-rich leachate; |
| Notes: | "PubMed-not-MEDLINEBarbosa Segundo, Inalmar D Silva, Tania F C V Moreira, Francisca C Silva, Gabriela V Boaventura, Rui A R Vilar, Vitor J P eng Netherlands 2018/12/24 Sci Total Environ. 2019 Mar 10; 655:1249-1260. doi: 10.1016/j.scitotenv.2018.11.274. Epub 2018 Nov 20" |
