Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation
Cadmium (Cd) is a highly toxic metal, occurring in municipal wastewater and stormwater as well as in wastewater from various industries. Char derived from the pyrolysis of municipal sewage sludge has the potential to be a low-cost sorption media for the removal of Cd. However, the balance between po...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IWA Publishing
2023-12-01
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| Series: | Water Science and Technology |
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| Online Access: | http://wst.iwaponline.com/content/88/11/2917 |
| _version_ | 1797389157449859072 |
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| author | Ida Sylwan Davide Bergna Hanna Runtti Lena Johansson Westholm Eva Thorin |
| author_facet | Ida Sylwan Davide Bergna Hanna Runtti Lena Johansson Westholm Eva Thorin |
| author_sort | Ida Sylwan |
| collection | DOAJ |
| description | Cadmium (Cd) is a highly toxic metal, occurring in municipal wastewater and stormwater as well as in wastewater from various industries. Char derived from the pyrolysis of municipal sewage sludge has the potential to be a low-cost sorption media for the removal of Cd. However, the balance between possible local char production and demand has not been assessed previously. In this study, the Cd sorption capacities of chars derived from primary (PSC) and secondary sludge (DSC), as well as the feasibility of char production for Cd sorbent purposes, and the pyrolysis energy balance were evaluated. Results showed that the sorption capacity of PSC (9.1 mg/g; 800 °C, 70 min) was superior to that of DSC (6.0 mg/g; 800 °C, 70 min), and increased with a higher pyrolysis temperature. Pyrolysis of primary sludge had a more favourable energy balance compared with the pyrolysis of digested sludge; however, when accounting for loss of biogas production the energy balance of primary sludge pyrolysis was negative. Assessment of the regional demand (Västerås, Sweden) indicated that PSC or DSC may cover the local Cd sorbent demand. However, it was estimated that large char volumes would be required, thus making the use of DSC/PSC less feasible.
HIGHLIGHTS
Char derived from the pyrolysis of municipal sewage sludge is a potential low-cost technology for Cd removal.;
Char derived from primary sludge showed superior sorption capacity compared to char derived from mixed digested sludge.;
Theoretical calculations indicated a potentially positive energy balance of digested sludge pyrolysis.;
Locally, sludge pyrolysis may not be motivated by Cd sorbent production alone.; |
| first_indexed | 2024-03-08T22:51:47Z |
| format | Article |
| id | doaj.art-a8ef71d81b8942e892005571769190cd |
| institution | Directory Open Access Journal |
| issn | 0273-1223 1996-9732 |
| language | English |
| last_indexed | 2024-03-08T22:51:47Z |
| publishDate | 2023-12-01 |
| publisher | IWA Publishing |
| record_format | Article |
| series | Water Science and Technology |
| spelling | doaj.art-a8ef71d81b8942e892005571769190cd2023-12-16T11:36:24ZengIWA PublishingWater Science and Technology0273-12231996-97322023-12-0188112917293010.2166/wst.2023.356356Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisationIda Sylwan0Davide Bergna1Hanna Runtti2Lena Johansson Westholm3Eva Thorin4 Mälardalen University, School of Business, Society and Engineering, Future Energy Center, P.O. Box 883, SE-721 23 Västerås, Sweden Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 8000, FI-90014 Oulu, Finland Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 8000, FI-90014 Oulu, Finland Mälardalen University, School of Business, Society and Engineering, Future Energy Center, P.O. Box 883, SE-721 23 Västerås, Sweden Mälardalen University, School of Business, Society and Engineering, Future Energy Center, P.O. Box 883, SE-721 23 Västerås, Sweden Cadmium (Cd) is a highly toxic metal, occurring in municipal wastewater and stormwater as well as in wastewater from various industries. Char derived from the pyrolysis of municipal sewage sludge has the potential to be a low-cost sorption media for the removal of Cd. However, the balance between possible local char production and demand has not been assessed previously. In this study, the Cd sorption capacities of chars derived from primary (PSC) and secondary sludge (DSC), as well as the feasibility of char production for Cd sorbent purposes, and the pyrolysis energy balance were evaluated. Results showed that the sorption capacity of PSC (9.1 mg/g; 800 °C, 70 min) was superior to that of DSC (6.0 mg/g; 800 °C, 70 min), and increased with a higher pyrolysis temperature. Pyrolysis of primary sludge had a more favourable energy balance compared with the pyrolysis of digested sludge; however, when accounting for loss of biogas production the energy balance of primary sludge pyrolysis was negative. Assessment of the regional demand (Västerås, Sweden) indicated that PSC or DSC may cover the local Cd sorbent demand. However, it was estimated that large char volumes would be required, thus making the use of DSC/PSC less feasible. HIGHLIGHTS Char derived from the pyrolysis of municipal sewage sludge is a potential low-cost technology for Cd removal.; Char derived from primary sludge showed superior sorption capacity compared to char derived from mixed digested sludge.; Theoretical calculations indicated a potentially positive energy balance of digested sludge pyrolysis.; Locally, sludge pyrolysis may not be motivated by Cd sorbent production alone.;http://wst.iwaponline.com/content/88/11/2917adsorbentadsorptionbiocharbiosolidsbiosorbent |
| spellingShingle | Ida Sylwan Davide Bergna Hanna Runtti Lena Johansson Westholm Eva Thorin Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation Water Science and Technology adsorbent adsorption biochar biosolids biosorbent |
| title | Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation |
| title_full | Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation |
| title_fullStr | Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation |
| title_full_unstemmed | Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation |
| title_short | Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation |
| title_sort | primary and digested sludge derived char as a cd sorbent feasibility of local utilisation |
| topic | adsorbent adsorption biochar biosolids biosorbent |
| url | http://wst.iwaponline.com/content/88/11/2917 |
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