Vivianite scaling in wastewater treatment plants: Occurrence, formation mechanisms and mitigation solutions
| العنوان: | Vivianite scaling in wastewater treatment plants: Occurrence, formation mechanisms and mitigation solutions |
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| المؤلفون: | A.I. Dugulan, M.C.M. van Loosdrecht, Leon Korving, K. Goubitz, T. Prot |
| المصدر: | Water Research, 197 |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | Environmental Engineering, 0208 environmental biotechnology, Mixing (process engineering), chemistry.chemical_element, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Waste Disposal, Fluid, Phosphates, Water Purification, Ferrous Compounds, Waste Management and Disposal, Scaling, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, Sewage, Ecological Modeling, Phosphorus, Pulp and paper industry, Pollution, Dewatering, 020801 environmental engineering, Deposition (aerosol physics), chemistry, Heat exchanger, Anaerobic equipment, Iron phosphate, Iron reduction, Environmental science, Sewage treatment, Vivianite, Centrifuge, Wwtp, Mesophile |
| الوصف: | The presence of soluble iron and phosphorus in wastewater sludge can lead to vivianite scaling. This problem is not often reported in literature, most likely due to the difficult identification and quantification of this mineral. It is usually present as a hard and blue deposit that can also be brown or black depending on its composition and location. From samples and information gathered in 14 wastewater treatment plants worldwide, it became clear that vivianite scaling is common and can cause operational issues. Vivianite scaling mainly occurred in 3 zones, for which formation hypotheses were discussed. Firstly, iron reduction seems to be the trigger for scaling in anaerobic zones like sludge pipes, mainly after sludge thickening. Secondly, pH increase was evaluated to be the major cause for the formation of a mixed scaling (a majority of oxidized vivianite with some iron hydroxides) around dewatering centrifuges of undigested sludge. Thirdly, the temperature dependence of vivianite solubility appears to be the driver for vivianite deposition in heat exchanger around mesophilic digesters (37 °C), while higher temperatures potentially aggravate the phenomenon, for instance in thermophilic digesters. Mitigation solutions like the use of buffer tanks or steam injections are discussed. Finally, best practices for safe mixing of sludges with each other are proposed, since poor admixing can contribute to scaling aggravation. The relevance of this study lays in the occurrence of ironphosphate scaling, while the use of iron coagulants will probably increase in the future to meet more stringent phosphorus discharge limits. |
| وصف الملف: | application/pdf |
| تدمد: | 1879-2448 0043-1354 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1763036952e623388e12b62f5d5afbed https://pubmed.ncbi.nlm.nih.gov/33845278 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....1763036952e623388e12b62f5d5afbed |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 18792448 00431354 |
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