Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization
This study investigates the fertilizer potential of sewage sludge from a sewage treatment plant through hydrothermal carbonization (HTC) by assessing the nutrient and heavy metal contents. HTC was conducted at 190 °C, 210 °C and 230 °C at a constant retention time of 10 min maintaining a solid-to-wa...
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Elsevier
2025-07-01
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| Series: | South African Journal of Chemical Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1026918525000393 |
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| author | Tahmid Sadique Mazumder Rifat Mahmud Md Mominur Rahman Md Shahinoor Islam |
| author_facet | Tahmid Sadique Mazumder Rifat Mahmud Md Mominur Rahman Md Shahinoor Islam |
| author_sort | Tahmid Sadique Mazumder |
| collection | DOAJ |
| description | This study investigates the fertilizer potential of sewage sludge from a sewage treatment plant through hydrothermal carbonization (HTC) by assessing the nutrient and heavy metal contents. HTC was conducted at 190 °C, 210 °C and 230 °C at a constant retention time of 10 min maintaining a solid-to-water ratio (1:9), converting the dried sewage sludge (DSS) from the sedimentation basin into hydrochar and a nutrient-rich liquid phase. The organic nitrogen declined in the solids from 1.75 % to 0.89–1.46 % through HTC, whereas the ammonium-N increased (300–800 mg/kg). In the HTC liquor, 325–525 ppm organic nitrogen and 320–760 ppm ammonium-N were found. Hydrochars exhibited significant total phosphorus ranging from 1.95 % to 2.35 % and higher C:N ratio reaching 13.45 for 230 °C treatment indicating slow-nitrogen release property. Among other nutrients, 1.23–1.38 % calcium (Ca), 0.22–0.25 % sodium (Na) and 0.19–0.21 % potassium (K) were found in the hydrochar. On the other hand, 52.2–561.7 ppm phosphates, 210.4–498.5 ppm Ca, 48.19–51.35 ppm K and 28.63–84.40 ppm Na were incorporated within the HTC liquor. Among the heavy metals, the concentrations of arsenic (As), copper (Cu), zinc (Zn), nickel (Ni), cadmium (Cd), lead (Pb) and chromium (Cr) were assessed. Four (Cu, Zn, Ni and As) of the eight metals were found to be above the toxicity limit. However, in the liquor, the concentrations of heavy metals were negligible (<2 ppm). Therefore, the study indicates that the use of sewage sludge has a potential to be used as nutrients for cultivating crops which will reduce the import of chemical fertilizer and enhance the utilization of sewage sludge sustainably. |
| format | Article |
| id | doaj-art-e9a4b95d3c1c4186a7abbca1cd1dd91d |
| institution | Kabale University |
| issn | 1026-9185 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | South African Journal of Chemical Engineering |
| spelling | doaj-art-e9a4b95d3c1c4186a7abbca1cd1dd91d2025-08-20T03:51:25ZengElsevierSouth African Journal of Chemical Engineering1026-91852025-07-015311712610.1016/j.sajce.2025.04.005Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonizationTahmid Sadique Mazumder0Rifat Mahmud1Md Mominur Rahman2Md Shahinoor Islam3Department of Chemical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka 1000, BangladeshDepartment of Chemical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka 1000, BangladeshDepartment of Chemical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka 1000, BangladeshDepartment of Textile Engineering, Daffodil International University, Dhaka 1341, Bangladesh; Corresponding author.This study investigates the fertilizer potential of sewage sludge from a sewage treatment plant through hydrothermal carbonization (HTC) by assessing the nutrient and heavy metal contents. HTC was conducted at 190 °C, 210 °C and 230 °C at a constant retention time of 10 min maintaining a solid-to-water ratio (1:9), converting the dried sewage sludge (DSS) from the sedimentation basin into hydrochar and a nutrient-rich liquid phase. The organic nitrogen declined in the solids from 1.75 % to 0.89–1.46 % through HTC, whereas the ammonium-N increased (300–800 mg/kg). In the HTC liquor, 325–525 ppm organic nitrogen and 320–760 ppm ammonium-N were found. Hydrochars exhibited significant total phosphorus ranging from 1.95 % to 2.35 % and higher C:N ratio reaching 13.45 for 230 °C treatment indicating slow-nitrogen release property. Among other nutrients, 1.23–1.38 % calcium (Ca), 0.22–0.25 % sodium (Na) and 0.19–0.21 % potassium (K) were found in the hydrochar. On the other hand, 52.2–561.7 ppm phosphates, 210.4–498.5 ppm Ca, 48.19–51.35 ppm K and 28.63–84.40 ppm Na were incorporated within the HTC liquor. Among the heavy metals, the concentrations of arsenic (As), copper (Cu), zinc (Zn), nickel (Ni), cadmium (Cd), lead (Pb) and chromium (Cr) were assessed. Four (Cu, Zn, Ni and As) of the eight metals were found to be above the toxicity limit. However, in the liquor, the concentrations of heavy metals were negligible (<2 ppm). Therefore, the study indicates that the use of sewage sludge has a potential to be used as nutrients for cultivating crops which will reduce the import of chemical fertilizer and enhance the utilization of sewage sludge sustainably.http://www.sciencedirect.com/science/article/pii/S1026918525000393Sewage sludgeHydrocharAmmonium-NPhosphateHydrothermal carbonization |
| spellingShingle | Tahmid Sadique Mazumder Rifat Mahmud Md Mominur Rahman Md Shahinoor Islam Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization South African Journal of Chemical Engineering Sewage sludge Hydrochar Ammonium-N Phosphate Hydrothermal carbonization |
| title | Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| title_full | Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| title_fullStr | Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| title_full_unstemmed | Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| title_short | Assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| title_sort | assessment of nutrient and heavy metal contents in a sewage sludge treatment plant through hydrothermal carbonization |
| topic | Sewage sludge Hydrochar Ammonium-N Phosphate Hydrothermal carbonization |
| url | http://www.sciencedirect.com/science/article/pii/S1026918525000393 |
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