Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents
An integrated process scheme is developed for valorizing filtered liquid digestates (FLD) from an industrial anaerobic digestion (AD) plant treating dairy-processing effluents with relatively low nutrient concentrations. The process scheme involves FLD treatment by nanofiltration (NF) membranes, fol...
Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
|
| Series: | Membranes |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0375/15/7/189 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1839615657786736640 |
|---|---|
| author | Anthoula C. Karanasiou Charikleia K. Tsaridou Dimitrios C. Sioutopoulos Christos Tzioumaklis Nikolaos Patsikas Sotiris I. Patsios Konstantinos V. Plakas Anastasios J. Karabelas |
| author_facet | Anthoula C. Karanasiou Charikleia K. Tsaridou Dimitrios C. Sioutopoulos Christos Tzioumaklis Nikolaos Patsikas Sotiris I. Patsios Konstantinos V. Plakas Anastasios J. Karabelas |
| author_sort | Anthoula C. Karanasiou |
| collection | DOAJ |
| description | An integrated process scheme is developed for valorizing filtered liquid digestates (FLD) from an industrial anaerobic digestion (AD) plant treating dairy-processing effluents with relatively low nutrient concentrations. The process scheme involves FLD treatment by nanofiltration (NF) membranes, followed by struvite recovery from the NF-retentate. An NF pilot unit (designed for this purpose) is combined with a state-of-the-art NF/RO process simulator. Validation of simulator results with pilot data enables reliable predictions required for scaling up NF systems. The NF permeate meets the standards for restricted irrigation and/or reuse. Considering the significant nutrient concentrations in the NF retentate (i.e., ~500 mg/L NH4-N, ~230 mg/L PO4-P), struvite recovery/precipitation is investigated, including determination of near-optimal processing conditions. Maximum removal of nutrients, through production of struvite-rich precipitate, is obtained at a molar ratio of NH<sub>4</sub>:Mg:PO<sub>4</sub> = 1:1.5:1.5 and pH = 10 in the treated stream, attained through the addition of Κ<sub>2</sub>HPO<sub>4</sub>, ΜgCl<sub>2</sub>·6H<sub>2</sub>O, and NaOH. Furthermore, almost complete struvite precipitation is achieved within ~30 min, whereas precipitate/solid drying at modest/ambient temperature is appropriate to avoid struvite degradation. Under the aforementioned conditions, a significant amount of dry precipitate is obtained, i.e., ~12 g dry mass per L of treated retentate, including crystalline struvite. The approach taken and the obtained positive results provide a firm basis for further development of this integrated process scheme towards sustainable large-scale applications. |
| format | Article |
| id | doaj-art-bf279877471245d39df4d0bb48a6e66a |
| institution | Matheson Library |
| issn | 2077-0375 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj-art-bf279877471245d39df4d0bb48a6e66a2025-07-25T13:29:43ZengMDPI AGMembranes2077-03752025-06-0115718910.3390/membranes15070189Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy EffluentsAnthoula C. Karanasiou0Charikleia K. Tsaridou1Dimitrios C. Sioutopoulos2Christos Tzioumaklis3Nikolaos Patsikas4Sotiris I. Patsios5Konstantinos V. Plakas6Anastasios J. Karabelas7Laboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceLaboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceLaboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceBIZIOS S.A., Vodiana, 40200 Elassona, GreeceTEDRA, 23 Papanastasiou Str., 41222 Larisa, GreeceLaboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceLaboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceLaboratory of Natural Resources and Renewable Energies, Chemical Process and Energy Resources Institute, Centre for Research and Technology-Hellas (CERTH), 57001 Thermi-Thessaloniki, GreeceAn integrated process scheme is developed for valorizing filtered liquid digestates (FLD) from an industrial anaerobic digestion (AD) plant treating dairy-processing effluents with relatively low nutrient concentrations. The process scheme involves FLD treatment by nanofiltration (NF) membranes, followed by struvite recovery from the NF-retentate. An NF pilot unit (designed for this purpose) is combined with a state-of-the-art NF/RO process simulator. Validation of simulator results with pilot data enables reliable predictions required for scaling up NF systems. The NF permeate meets the standards for restricted irrigation and/or reuse. Considering the significant nutrient concentrations in the NF retentate (i.e., ~500 mg/L NH4-N, ~230 mg/L PO4-P), struvite recovery/precipitation is investigated, including determination of near-optimal processing conditions. Maximum removal of nutrients, through production of struvite-rich precipitate, is obtained at a molar ratio of NH<sub>4</sub>:Mg:PO<sub>4</sub> = 1:1.5:1.5 and pH = 10 in the treated stream, attained through the addition of Κ<sub>2</sub>HPO<sub>4</sub>, ΜgCl<sub>2</sub>·6H<sub>2</sub>O, and NaOH. Furthermore, almost complete struvite precipitation is achieved within ~30 min, whereas precipitate/solid drying at modest/ambient temperature is appropriate to avoid struvite degradation. Under the aforementioned conditions, a significant amount of dry precipitate is obtained, i.e., ~12 g dry mass per L of treated retentate, including crystalline struvite. The approach taken and the obtained positive results provide a firm basis for further development of this integrated process scheme towards sustainable large-scale applications.https://www.mdpi.com/2077-0375/15/7/189dairy industry effluentsanaerobic digestionfiltered liquid digestate valorizationnanofiltrationstruvite recovery |
| spellingShingle | Anthoula C. Karanasiou Charikleia K. Tsaridou Dimitrios C. Sioutopoulos Christos Tzioumaklis Nikolaos Patsikas Sotiris I. Patsios Konstantinos V. Plakas Anastasios J. Karabelas Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents Membranes dairy industry effluents anaerobic digestion filtered liquid digestate valorization nanofiltration struvite recovery |
| title | Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents |
| title_full | Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents |
| title_fullStr | Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents |
| title_full_unstemmed | Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents |
| title_short | Valorization of Anaerobic Liquid Digestates Through Membrane Processing and Struvite Recovery—The Case of Dairy Effluents |
| title_sort | valorization of anaerobic liquid digestates through membrane processing and struvite recovery the case of dairy effluents |
| topic | dairy industry effluents anaerobic digestion filtered liquid digestate valorization nanofiltration struvite recovery |
| url | https://www.mdpi.com/2077-0375/15/7/189 |
| work_keys_str_mv | AT anthoulackaranasiou valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT charikleiaktsaridou valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT dimitrioscsioutopoulos valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT christostzioumaklis valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT nikolaospatsikas valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT sotirisipatsios valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT konstantinosvplakas valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents AT anastasiosjkarabelas valorizationofanaerobicliquiddigestatesthroughmembraneprocessingandstruviterecoverythecaseofdairyeffluents |