Application of advanced integrated technologies (membrane and photo-oxidation processes) for the removal of cecs contained in urban wastewater
- Autores: Roger Dennis Deemter
- Directores de la Tesis: Sixto Malato Rodríguez (dir. tes.), Ana María Amat Payá (dir. tes.)
- Lectura: En la Universitat Politècnica de València ( España ) en 2024
- Idioma: inglés
- Tribunal Calificador de la Tesis: José Antonio Casas de Pedro (presid.), Antonio Arqués Sanz (secret.), Paolo Calza Bini (voc.)
- Programa de doctorado: Programa de Doctorado en Ingeniería Textil por la Universitat Politècnica de València
- Materias:
- Enlaces
- Tesis en acceso abierto en: RiuNet
- Resumen
Water turned to be one of Earths scarcest commodities. Therefore, novel technologies need to be developed, as appropriate treatment of produced urban wastewaters (UWWs) for its reuse as irrigation waters or aquifer recharge. Multiple advanced technologies are proven effective when applied solely. These technologies are often not applied or integrated into conventional UWW treatment. Resulting in missing out on potential synergetic effects. For these reasons that research into the combining and integration of these novel technologies is of the utmost importance. When thus applied, these combined technologies are also known and indicated as Advanced Integrated Technologies.
Research work was conducted on the performance of a pilot scale nanofiltration (NF) plant for UWW pre-concentration, followed by the application of (chemical) treatment methods, in order to treat the produced concentrate and permeate streams. Advanced Oxidation Processes (AOPs), such as the (solar) photo-Fenton process make use of the catalytic cycle of iron (Fe2+ and Fe3+), UV-vis light, along with an oxidizing agent, such as hydrogen peroxide (H2O2), producing highly reactive and non-selective hydroxyl radicals (*OH). This (solar) photo-Fenton process is applied at acidic pH3, in order to prevent iron precipitation, or at circumneutral pH by applying chelating agents such as Ethylenediamine-N, N'-disuccinic acid (EDDS).
Preconcentration is an essential step before applying AOPs as tertiary treatment of UWWTP effluents, as it significantly lowers the to be treated volume, and therefore the overall costs.
Treating the concentrate stream from the NF by the solar photo-Fenton process showed to be effective for the removal of different microcontaminants (MCs) when H2O2 was used as an oxidation agent. Opposite to that, the application of persulfate and its derived radicals showed lower degradation of the selected MC. For which a higher MC degradation is adhered to a directly proportional lower toxicity. Selected (MCs) were caffeine, imidacloprid, thiacloprid, carbamazepine, and diclofenac.
Further research work covered UWWTP effluent valorization by the recovery of ammonium, with combined MC elimination by NF and different advanced AOPs, in order to produce permeate streams for direct crop fertilization and irrigation, also called 'fertigation'. Including solar photo-Fenton, but also combined with electrooxidation (EO) processes. Solar photo-Fenton was most effective when treating NF concentrate streams at circumneutral pH, at MC concentration lower than 1 mg/L, to obtain rapid MC degradation. High saline and concentrated NF concentrate streams are ideal to be treated by EO processes, while possessing high conductivity. Obtaining significant lower electric consumption by solar assistance.
MC retention efficiency by NF and toxicity after AOP treatments was also assessed by determining the permeate phytotoxicity. Results showed that permeates could lower seed germination if they would be used for crops (Sorghum saccharatum, Sinapis alba and Lepidium sativum). Contrary to that, it was showed that irrigation with the produced permeates generally promoted root development, while shoot development only thrived when using permeates which had concentration factors lower than 2. Toxicity studies showed that permeate streams should first be diluted with a minimum of 50% fresh water, in order to be suitable for direct crop irrigation in agriculture.
Conducted research work also included the assessment of a priorly developed (collaboration with an PhD within MSCA AQUAlity) photocatalytic TiO2-ZrO2 ceramic ultrafiltration (UF) membrane. Flux decline can be reversed when the photocatalytic UF membrane was irradiated by light in a solar simulator. Microbiological retention of the UF membrane was determined by deploying a Gram-negative bacterial strain, Pseudomonas aeruginosa (P. Aeruginosa). It was able to consistently retain till an order of magnitude of 1x10^4 CFU/ml.
