The thesis was developed within the Life DeNtreat project (LIFE 16 ENV / IT / 000345, Decentralized innovative treatment of ammonium-rich urban wastewater), in the framework of the LIFE program (L'Instrument Financier pour l'Environnement), European financial instrument for environment and climate protection. The thesis aims to verify the applicability of the PN / anammox process (Partial Nitritation and ANaerobic AMMonium OXidation microorganism) for the treatment of wastewater discharged by digital textile printing processes, and to verify the feasibility of a treatment solution that allows reduce the concentration of nitrogen within the limits authorized for discharge into a public sewer system. Digital textile printing (DTP) is a rapidly expanding technology in the textile processing sector, thanks to the significant productivity and flexibility improvements made in this globally spread industrial sector. On the other hand, the waste water from the rinsing and washing baths is rich in nitrogen (up to 600 mg/L, as ammonium and organic nitrogen), due to the massive use of urea in conditioning the fabric before printing. Such a high concentration prevents the direct discharge into water bodies and even into public sewers. Dedicated on-site pre-treatment of these industrial waste water is required and space / energy efficient technology is required for on-site application. Autotrophic nitrogen removal is a consolidated solution for nitrogen-rich wastewater treatment. In the LIFE DeNTreat project, a partial nitritation process (PN) is applied followed by a single-stage process based on anammox biomass as a decentralized treatment of this type of waste, characterized by lower environmental impact, lower energy consumption and reagents, in addition to that from a much lower production of residues (sludge). In particular, the experimentation was conducted to evaluate the treatability with the PN / anammox process of wastewater produced by the digital printing processes of various companies, one of which was Italian (Stamperia of Cassina Rizzardi, SCR, in the province of Como) and two Portuguese ( Estamparia Adalberto, Porto; Satinskin, Braga). For the purpose of the research, an experimentation on a laboratory pilot plant was run and allowed to define the control of the best operating conditions. The work confirmed the possibility of treating these wastes, also highlighting the possibility of converting urea into ammoniacal nitrogen, thanks to the action of some ammonium oxidizing bacterial strains (AOB). In some cases, the presence of inhibiting compounds, did not allow to reach the maximum theoretically obtainable results, and further investigations will be necessary to better understand what corrective actions can be adopted. The management of the process and, in particular, operational control of parameters such as pH, dissolved oxygen and temperature, was confirmed to be of fundamental importance to guarantee the adaptation of the biomass to this type of wastewater. In addition to this, a simulation model of the biological process was developed, with the use of the BiowinTM software platform, which made it possible to assess the influence of the operating parameters on the efficiency of the process.
La tesi è stata sviluppata nell’ambito del progetto Life DeNtreat (LIFE 16 ENV/IT/000345, Decentralized innovative treatment of ammonium-rich urban wastewater), nell’ambito del programma LIFE (L’Instrument Financier pour l’Environnement), strumento di finanziamento europeo per la tutela dell’ambiente e del clima. La tesi si propone di verificare l’applicabilità del processo PN/anammox (Partial Nitritation e ANaerobic AMMonium OXidation microorganism) per il trattamento delle acque di rifiuto dell’industria della stampa digitale tessile, e verificare la fattibilità di una soluzione di trattamento che permetta di ridurre la concentrazione di azoto entro i limiti autorizzati per lo scarico in una rete di fognatura pubblica. La stampa digitale su tessuto è una tecnologia in rapida espansione nel settore della trasformazione tessile, grazie ai significativi miglioramenti di produttività e flessibilità apportati in questo settore industriale diffuso a livello globale. D'altra parte, le acque reflue provenienti dai bagni di risciacquo sono ricche di azoto (fino a 600 mg/L presente come azoto ammoniacale e organico), a causa dell'uso massiccio di urea nel condizionare il tessuto prima della stampa. Una concentrazione così elevata impedisce lo scarico diretto nei corpi idrici e persino nelle fognature pubbliche. È necessario un pretrattamento in loco dedicato di queste acque reflue industriali ed è necessaria una tecnologia efficiente in termini di spazio / energia adatta per l'applicazione in loco. La rimozione autotrofa dell'azoto è una soluzione consolidata per il trattamento delle acque reflue ricche di azoto. Nel progetto LIFE DeNTreat si applica processo di nitritazione parziale (PN) seguita da un processo basato su biomasssa anammox, a singolo stadio, come trattamento decentralizzato di questo tipo di reflui, caratterizzato da minore impatto ambientale, da minori consumi energetici e di reagenti, oltre che da una assai minore produzione di residui (fanghi). In particolare, la sperimentazione è stata condotta per valutare la trattabilità con il processo PN/anammox di reflui prodotti dai processi di stampa digitale di diverse aziende di cui una italiana (Stamperia di Cassina Rizzardi, SCR, in provincia di Como) e due portoghesi (Estamparia Adalberto, Porto; Satinskin, Braga). Al fine della ricerca è stato utilizzato un impianto pilota da laboratorio che ha permesso il controllo delle condizioni operative ideali per il lavoro della biomassa. Il lavoro ha confermato la possibilità di trattamento di questi reflui evidenziando anche la possibilità di convertire l’urea in azoto ammoniacale grazie all’azione di alcuni ceppi batterici ammonio ossidanti (AOB). In alcuni casi, la presenza di composti inibenti, non hanno permesso di raggiungere i risultati teoricamente ottenibili, e ulteriori approfondimenti saranno necessari per comprendere meglio quali azioni correttive possano essere adottate. La gestione del processo e, in particolare, il controllo dei parametri principali come pH, ossigeno disciolto e temperatura, sono di fondamentale importanza per garantire l’adattamento della biomassa a questo tipo di reflui. Oltre a ciò, si è sviluppato un modello di simulazione del processo biologico, con l’utilizzo della piattaforma software BiowinTM, che ha permesso di valutare l’influenza dei parametri operativi sull’efficienza del processo.
Rimozione biologica dell'azoto da reflui della stampa digitale tessile in reattore a biomassa granulare
MOLTENI, ANDREA
2018/2019
Abstract
The thesis was developed within the Life DeNtreat project (LIFE 16 ENV / IT / 000345, Decentralized innovative treatment of ammonium-rich urban wastewater), in the framework of the LIFE program (L'Instrument Financier pour l'Environnement), European financial instrument for environment and climate protection. The thesis aims to verify the applicability of the PN / anammox process (Partial Nitritation and ANaerobic AMMonium OXidation microorganism) for the treatment of wastewater discharged by digital textile printing processes, and to verify the feasibility of a treatment solution that allows reduce the concentration of nitrogen within the limits authorized for discharge into a public sewer system. Digital textile printing (DTP) is a rapidly expanding technology in the textile processing sector, thanks to the significant productivity and flexibility improvements made in this globally spread industrial sector. On the other hand, the waste water from the rinsing and washing baths is rich in nitrogen (up to 600 mg/L, as ammonium and organic nitrogen), due to the massive use of urea in conditioning the fabric before printing. Such a high concentration prevents the direct discharge into water bodies and even into public sewers. Dedicated on-site pre-treatment of these industrial waste water is required and space / energy efficient technology is required for on-site application. Autotrophic nitrogen removal is a consolidated solution for nitrogen-rich wastewater treatment. In the LIFE DeNTreat project, a partial nitritation process (PN) is applied followed by a single-stage process based on anammox biomass as a decentralized treatment of this type of waste, characterized by lower environmental impact, lower energy consumption and reagents, in addition to that from a much lower production of residues (sludge). In particular, the experimentation was conducted to evaluate the treatability with the PN / anammox process of wastewater produced by the digital printing processes of various companies, one of which was Italian (Stamperia of Cassina Rizzardi, SCR, in the province of Como) and two Portuguese ( Estamparia Adalberto, Porto; Satinskin, Braga). For the purpose of the research, an experimentation on a laboratory pilot plant was run and allowed to define the control of the best operating conditions. The work confirmed the possibility of treating these wastes, also highlighting the possibility of converting urea into ammoniacal nitrogen, thanks to the action of some ammonium oxidizing bacterial strains (AOB). In some cases, the presence of inhibiting compounds, did not allow to reach the maximum theoretically obtainable results, and further investigations will be necessary to better understand what corrective actions can be adopted. The management of the process and, in particular, operational control of parameters such as pH, dissolved oxygen and temperature, was confirmed to be of fundamental importance to guarantee the adaptation of the biomass to this type of wastewater. In addition to this, a simulation model of the biological process was developed, with the use of the BiowinTM software platform, which made it possible to assess the influence of the operating parameters on the efficiency of the process.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/151853