Ion exchange represents one of the most promising processes for ammonium recovery from municipal ... more Ion exchange represents one of the most promising processes for ammonium recovery from municipal wastewater (MWW). However, most previous studies on ammonium ion exchange did not optimize the process or evaluate its robustness under real operational conditions. This experimental study aimed at (i) developing a procedure for the selection of a sorbent for selective ammonium removal/recovery from MWW, (ii) validating the procedure by applying it to several sorbents, (iii) performing a preliminary optimization and robustness assessment of ammonium removal/recovery with the selected sorbent. The application of the procedure to natural and synthetic zeolites and a cation exchange resin confirmed that batch isotherm tests need to be integrated by continuous-flow tests. The selected sorbent, a natural mixture of Chabazite and Phillipsite, resulted in high performances in terms of cation exchange capacity (33 mg N g dry resin − 1), ammonium operating capacity (5.2 mg N g dry resin − 1), ammonium recovery yield (78-91%) and selectivity towards ammonium. The process performances resulted stable during 7 adsorption/desorption cycles conducted with MWW treatment plant effluents in a 60-cm column. The switch to a highly saline effluent produced in a hotspot of seawater intrusion did not determine significant changes in performances. Contact time was reduced to 6 min without any decrease in performances. Potassiumwell tolerated by cropswas selected as the regenerating agent, in the perspective to produce a desorbed product to be re-used as fertilizer. The study shows that Chabazite/Phillipsite has a high capacity to recover ammonium from MWW in a circular economy approach.
Among the available technologies for ammonium removal from wastewater, ion exchange represents on... more Among the available technologies for ammonium removal from wastewater, ion exchange represents one of the most promising ones in the perspective to recover ammonium and produce a fertilizing product. However, the vast majority of previous studies on ammonium ion exchange did not evaluate the process robustness under real operational conditions nor optimized the desorption step. In this paper, tests of ammonium removal and recovery were conducted on a metakaolin K-based geopolymer, compared with a high-performing Italian natural zeolite in K-form. Real municipal and saline wastewater was treated in a continuous flow pilot plant equipped with a 60-cm adsorption bed (bed volume 203 mL, sorbent mass 145-173 g, empty bed contact time 10 minutes). Geopolymer granules showed higher performances in terms of selectivity towards ammonium, operating capacity (8.5 mgN g-1 dry adsorbent at an inlet concentration of 40 mgN L-1), bed volumes of wastewater treated at the selected breakpoint (149). Geopolymer resulted to be a cost-effective adsorbent for wastewater treatment capable to adsorb cations by ion exchange, allowing a fractionated desorption procedure that led to recover ammonium in a solution composed mainly by NH4NO3 (37%wt) and KNO3 (56%wt), potentially usable as fertilizer. The geopolymer robustness was assessed after repeated adsorption/regeneration cycles showing that the geopolymer mechanical and morphological properties did not deteriorate. The results make the tested geopolymer a very promising material for the optimization and scale-up of the ammonium recovery process in a circular economy perspective.
Convegno GRICU 2012 - Ingegneria Chimica: dalla nanoscala alla macroscala, 2012
La biodegradazione aerobica cometabolica di cloroformio ad opera di un consorzio batterico butano... more La biodegradazione aerobica cometabolica di cloroformio ad opera di un consorzio batterico butano-utilizzatore \\ue8 stata studiata per 1 anno in un reattore a colonna riempito con sabbia rappresentativo di una porzione di acquifero. Obiettivi dello studio erano: a) sviluppare l\\u2019alimentazione pulsata di substrato e ossigeno; b) testare e calibrare un modello cinetico di cometabolismo aerobico combinato con un modello fluidodinamico 1-D con dispersione; c) sviluppare una procedura numerica di calibrazione del modello (una variante del metodo di Gauss-Newton). L\\u2019applicazione di 6 tipologie di alimentazione pulsata ha consentito l\\u2019individuazione di un programma di pulsazione efficace nell\\u2019evitare l\\u2019intasamento del mezzo e in grado di garantire soddisfacenti prestazioni di degradazione del cloroformio
9th Euroepan Congress of Chemical Engineering / 2nd European Congress of Applied Biotechnology, 2013
BACKGROUND. Bio-hydrogen production from organic residues is an attractive process that combines ... more BACKGROUND. Bio-hydrogen production from organic residues is an attractive process that combines energy generation with waste treatment. This work represents the continuation of a previous study of biological H2 production from food industry wastes (Cappelleti et al., J. Chem. Technol. Biotechnol. 87:1291-1301), where the comparison of four thermophilic Thermotoga strains and four carriers for biomass immobilization led to the identification of T. neapolitana as the best-performing strain and of a porous ceramic material named Biomax as the best-performing support for biofilm formation. AIMS. The goals of this work were: a) to develop and calibrate a kinetic model of H2 production from glucose, molasses and cheese whey by suspended and attached cells of T. neapolitana, and b) to set-up and optimize a continuous-flow process of H2 production from cheese whey by T. neapolitana in a 20-L stirred reactor. METHODS. The experimental H2 rates used to develop the kinetic model were obtained from suspended- and attached-cell batch tests conducted in 120-mL bioreactors, exposed to different initial concentrations of glucose, molasses or cheese whey (0.1-95 g L-1, as total sugars). The process was scaled-up in a 20-L fermentor, fed only with cheese whey in consideration of the significantly higher production of this waste in Northern Italy, in comparison with molasses. The fermentor was operated initially with suspended-cells, and subsequently with attached-cells. To immobilize T. neapolitana in the fermentor, 5 L of the previously selected carrier were introduced in pockets made with steel net and fixed to the top and bottom of the vessel. RESULTS. The H2 specific production rates obtained with suspended and attached cell tests of T. neapolitana are shown in Figure 1, together with the best fitting simulations performed with the Haldane substrate inhibition model. The corresponding values of the kinetic parameters are reported in Table 1. For all the substrates studied, a marked substrate inhibition was noticed. The attached-cell tests resulted in higher rates than the suspended-cell ones, in particular in the case of glucose and molasses. Further tests indicated the absence of oxygen inhibition (studied range: 0-1% in the headspace, or 0-0.21 mgdissolved O2 L-1) and of product (H2) inhibition (studied range: 0-60% in the headspace, or 0-0.73 mgdissolved H2 L-1). The batch tests of H2 production from cheese whey conducted in the 20-L fermentor led to a productivity of 6.8 mmolH2 L-1 day-1 with suspended cells, and 22.5 mmolH2 L-1 day-1 with attached cells. The fermentor was also operated with attached cells in continuous-flow mode, with hydraulic retention times (HRT) in the 0.8-2.9 day range. The resulting H2 productivity showed an increasing trend with decreasing HRT, with a maximum value of 125 mmolH2 L-1 day-1. CONCLUSIONS. The calibration of a model of thermophilic H2 production from different wastes and the successful scale-up of the process of cheese whey conversion into H2 in a continuous-flow 20-L bioreactor pose the basis for a model-based optimization of the attached-cell process, and for its further scale-up to a pilot plant
INCA–Interuniv. Consortium Chemistry for Environ., 2005
Chlorinated aliphatic hydrocarbons (CAHs) are widespread, toxic and recalcitrant subsurface conta... more Chlorinated aliphatic hydrocarbons (CAHs) are widespread, toxic and recalcitrant subsurface contaminants. Among the different remediation options for CAH-contaminated sites, aerobic bioremediation represents a very interesting one, thanks to the high depletion rates achievable, the possibility to transform several CAHs into non-toxic, easily biodegradable compounds and the limited excavation works required. In most cases, the aerobic bioremediation of a CAH-polluted site can be performed only by means of cometabolism, which requires the supply of a suitable growth substrate. Cometabolic bioremediation is a rather complex process, whose outcome is not predictable on the basis of a mere site characterization: it is therefore necessary to perform a previous feasibility study. In several cases, the biological process can be significantly speeded up by means of the addition of previously selected microbial inocula. Despite the significant progresses made during the last years, the aerobic bioremediation of CAH-contaminated sites is not yet a widespread remediation technology
7th International Conference on Environmental Engineering and Management, 2013
Chlorinated aliphatic hydrocarbons (CAHs) are widespread groundwater contaminants. Aerobic cometa... more Chlorinated aliphatic hydrocarbons (CAHs) are widespread groundwater contaminants. Aerobic cometabolism, that requires the supply of a suitable growth substrate, represents an interesting option for the remediation of CAH-contaminated aquifers, thanks to its capability to lead to the complete mineralization of a very wide range of CAHs. The aim of this study was to develop and validate a procedure relative to the lab-scale tests required to obtain the essential information for the design of a process of CAH aerobic cometabolism in a packed bed reactor (PBR). To validate the procedure, the latter was applied to the development of a PBR process for the on-site aerobic cometabolism of an aquifer contaminated by trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (TeCA). The specific goals of this study, corresponding to the main steps of the above-mentioned procedure, were: (i) to select the best growth substrate for the aerobic cometabolic process, and to develop and characterize an effective CAH-degrading microbial consortium, obtained from the site\u2019s indigenous biomass by exposition to the selected substrate; (ii) to select the best carrier for the PBR process, and to evaluate the effect of bacterial adhesion on the developed suspended-cell consortium; and (iii) to identify and test suitable chemical-physical remediation alternatives in the case of presence of CAHs poorly biodegradable through AC. With regard to the growth substrate selection, the comparison of the CAH degradation performances obtained with 5 candidate substrates (methane, propane, butane, pentane and phenol) led to the selection of butane and to the development from the site\u2019s indigenous biomass of a suspended-cell consortium capable to degrade TCE (TCE first-order constant (k1,TCE) = 96 L gprotein-1 d-1 at 30 \ub0C and 4.3 L gprotein-1 d-1 at 15 \ub0C) with a 90% mineralization of the organic Cl. Based on PCR-DGGE analysis of the 16S rRNA genes followed by band excision and sequencing, the microbial consortium enriched was mainly composed of Bacteroidetes and Alpha- and Beta-Proteobacteria that were distantly related to known CAH-cometabolizing bacteria. With regard to the selection of the best-performing biofilm carrier, a preliminary screening based on the previous experience of the research group led to the pre-selection of four candidate biofilm carriers (porous materials specifically designed for biofilm processes): Biomax, Biomech, Biopearl and Cerambios. The choice of the best-performing carrier was made by means of a 2-level procedure. The 1st level consisted of batch tests, operated both at 30 and 15 \ub0C, whereas the 2nd level consisted of continuous-flow tests, operated at 30 \ub0C. The 30 \ub0C continuous-flow tests were conducted in four 1 L packed columns, connected to a feeding system designed so as to attain a pulsed feed of both oxygen and the selected growth substrate (butane). The four columns were operated in continuous mode for about 100 days. The results of the attached-cell tests were compared on the basis of the TCE normalized degradation rate ( and ) and of the attached cell concentration attained, at the two temperatures, at the end of the biofilm development process. On the basis of both the batch and the continuous-flow tests, Biomax resulted the best-performing biofilm carrier. Biomass immobilization on the carrier changed remarkably the structure of the microbial consortium. The effect on k1,TCE of biomass attachment depended on temperature: at 15 \ub0C the attached consortium performed slightly better than the suspended one, whereas at 30 \ub0C an opposite trend was noticed. On the basis of a 1st-order simulation, a 99.9% TCE conversion can be attained, at the site\u2019s temperature, with a 9-hour HRT. Lastly, the low TeCA degradation rate by the developed consortium suggested the introduction of a chemical pre-treatment based on the TeCA to TCE conversion via \uf062-elimination, a very fast reaction at alkaline pH. On the basis of the overall results, the procedure for the development of a PBR AC process appears to be correctly designed and generally applicable to CAH contaminated sites
Ecomondo 05. IV conferenza: Aspetti procedurali ed innovazione (bio)tecnologica nella gestione e bonifica dei siti contaminati, 2005
L\u2019obiettivo di questo lavoro \ue8 stato lo studio del processo di biodegradazione aerobica c... more L\u2019obiettivo di questo lavoro \ue8 stato lo studio del processo di biodegradazione aerobica cometabolica dell\u20191,1,2,2-tetracloroetano (TeCA) ad opera di biomasse metanotrofe e propanotrofe. La sperimentazione \ue8 stata condotta in microcosmi allestiti sia in condizioni slurry che, limitatamente alla biomassa propanotrofa, liquido/gas. I risultati indicano che il TeCA pu\uf2 essere biodegradato tramite cometabolismo aerobico ad opera sia di biomasse metano-utilizzatrici che propano-utilizzatrici nell\u2019intervallo 0-600 mg/l aq., e che tale processo pu\uf2 essere protratto per parecchi mesi senza che si verifichino fenomeni di inattivazione o danneggiamento delle biomasse oggetto di studio. Il trattamento di bioaugmentation ha consentito di ridurre drasticamente il lag-time per l\u2019avvio del processo degradativo cometabolico. I risultati positivi ottenuti nei microcosmi liquido/gas dimostrano che, a partire da pochi ml di biomassa propano-utilizzatrice sviluppata nei microcosmi slurry, \ue8 possibile produrre elevati quantitativi di inoculo tramite un processo di crescita in bioreattori non contenenti terreno, senza che si verifichino significative diminuzioni dell\u2019efficacia dell\u2019inoculo nella degradazione del TeCA
The goal of this study was to develop a mesophilic anaerobic co-digestion (co-AD) process of oliv... more The goal of this study was to develop a mesophilic anaerobic co-digestion (co-AD) process of olive mill wastewater (OMW) and sewage sludge (SwS) from municipal wastewater treatment. Different volumetric OMW:SwS ratios up to 100% OMW were fed in continuous 1.7-L bioreactors. The reactors fed with raw OMW (rOMW) performed better than those fed with OMW dephenolized by adsorption (dOMW). At a 23-day hydraulic retention time (HRT) the best performances were obtained in the reactor fed with 25% rOMW, with a 105% increase in methane yield in comparison to the 100% SwS test. At a 40-day HRT, the reactor fed with 40% rOMW attained a 268 NLCH4/kgVS methane yield (144% increase in comparison to 100% SwS). These results prove the feasibility of co-digesting with SwS the entire OMW production in regions characterized by intense olive oil production, with a strong increase in methane production.
BACKGROUND: Olive mill wastewaters (OMWs) represent a major environmental concern due to their hi... more BACKGROUND: Olive mill wastewaters (OMWs) represent a major environmental concern due to their high organic load and phytotoxic activity. The selective recovery of phenolic compounds (PCs) from OMW is promising, thanks to the antioxidant and antimicrobial properties of PCs. The goal of this work was to perform the life cycle assessment (LCA) and cost-benefit analysis (CBA) of a fullscale process of PC adsorption/desorption on resin Amberlite XAD16N. The industrial process was designed on the basis of laboratory tests aimed at performing a preliminary process optimization. RESULTS: Adsorption tests were conducted at different velocities in a 1.8-m column packed with XAD16N. The optimal superficial velocity and retention time (2.78 m/h and 0.56 h) allowed the attainment of satisfactory performances in terms of resin operating capacity (0.46), PC adsorption yield (0.92), PC mass fraction in the sorbed product (0.50 gPC/gVS) and specific antioxidant activity (3-6 gascorbic acid/gPC). Si...
The objective of this work was to study a process of 1,1,2,2-tetrachloroethane (TeCA) biodegradat... more The objective of this work was to study a process of 1,1,2,2-tetrachloroethane (TeCA) biodegradation via aerobic cometabolism by methane-utilizing and propane-utilizing microbial cultures. Both cultures were studied by means of slurry microcosm tests; the propane-utilizing culture was further studied in liquid/gas bioreactors. TeCA was biodegraded by both microbial cultures via aerobic cometabolism in the 0-600 μg/L concentration range. The process was successfully continued for several months without any apparent inhibitory or toxic effect on the microbial cultures tested. In bioaugmented microcosms, the inoculation of the propane-utilizing culture developed in the slurry microcosms led to a marked reduction of the lag-period required for the onset of TeCA degradation. The positive results obtained from the liquid/gas reactors show that it is possible to grow the isolated propane-utilizing culture in a liquid/gas bioreactor without any observable loss of TeCA degradation capacity. This conclusion is relevant with respect to the production of significant amounts of inoculum to utilize in bioaugmentation treatments
Extreme weather and climate change policy failures are the greatest threats the world is facing o... more Extreme weather and climate change policy failures are the greatest threats the world is facing over the next 10 years. The Middle East and North Africa (MENA) region is the driest area in the world and is already affected by desertification, groundwater over-exploitation, and seawater intrusion into aquifers. The consequences of climate change for water security in MENA will be amplified given that the expected population growth and economic growth is projected to result in a 47 % increase in water demand by 2035.
A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from ... more A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from PC-rich wastes and wastewaters was innovatively proposed and applied to compare 4 neutral resins (Amberlite XAD 16, Optipore SD-2, Amberlite FPX66, Amberlite XAD761) and 1 ion-exchange resin (IRA958 Cl) for PC recovery from a Tunisian olive mill wastewater (OMW).
Il risanamento di siti contaminanti \ue8 divenuto una delle pi\uf9 importanti emergenze ambiental... more Il risanamento di siti contaminanti \ue8 divenuto una delle pi\uf9 importanti emergenze ambientali, sia in Italia che in Europa. Il documento preparatorio per una futura possibile Direttiva Europea sulla \u201cProtezione del Suolo\u201d (Proposta COM2006/232) stima che 3.5 milioni di siti potenzialmente contaminanti dovranno essere individuati e caratterizzati in Europa, con un costo di circa 240 milioni di \u20ac per almeno 25 anni. La Proposta stima che circa 500.000 siti contaminati dovranno poi essere effettivamente risanati. In Italia esistono gi\ue0 57 siti contaminati di interesse nazionale (700.000 ha, pi\uf9 del 2% del territorio nazionale, Legge n.426/1998 e s.m.i), per i quali esiste un finanziamento pubblico di circa 750 milioni \u20ac, destinato principalmente alla messa in sicurezza di emergenza. Inoltre, si stima che circa 15.000 siti contaminati di interesse locale dovranno essere caratterizzati e forse bonificati, con un costo di circa 25-30 miliardi di \u20ac nei prossimi 15 anni. Il primo recettore della contaminazione del sito \ue8 solitamente l'acqua sotterranea al di sotto del sito stesso, da cui la contaminazione pu\uf2 facilmente migrare verso altri recettori, incluso l\u2019uomo. L\u2019acqua sotterranea \ue8 un recettore molto sensibile, essendo una risorsa importante e limitata, i cui usi reali e potenziali sono ostacolati persino da bassi livelli di contaminazione. Tra i contaminanti di un\u2019acqua sotterranea, i composti clorurati sono certamente i pi\uf9 diffusi: l\u2019Helmholtz Center for Environmental Research della Germania stima che i composti clorurati (principalmente tetracloroetilene e tricloroetilene, PCE e TCE) siano presenti in pi\uf9 del 50% dei casi. Essi sono anche pericolosi dal punto di vista ambientale ed igienico-sanitario, in quanto a) la maggior parte di essi sono altamente tossici e sospetti cancerogeni, b) sono in grado di formare fasi separate, spesso con densit\ue0 maggiore dell\u2019acqua (DNAPL) e quindi c) permangono a concentrazioni pi\uf9 alte e per un periodo pi\uf9 lungo rispetto ad altri contaminanti. Quando una falda acquifera \ue8 contaminata, l\u2019Autorit\ue0 Pubblica richiede di solito misure di messa in sicurezza d\u2019emergenza, per evitare l\u2019espansione della contaminazione verso recettori sensibili. Tali misure sono generalmente attuate attraverso barriere passive (diaframmi impermeabili con trincee di drenaggio) o dinamiche (barriere idrauliche), il che comporta l\u2019attivazione di un sistema di depurazione \u201con site\u201d dell\u2019acqua estratta (\u201cpump-and-treat\u201d, P&T). Il grande sviluppo dei sistemi P&T \ue8 dovuto anche alla relativa facilit\ue0 di gestione e alla consolidata esperienza acquisita negli anni. Tuttavia, il P&T presenta diversi svantaggi: a) esso non preserva l\u2019acqua di falda come risorsa quantitativa potenzialmente disponibile per l\u2019uomo poich\ue9 spesso non \ue8 possibile (per vari motivi) la re-introduzione dell\u2019acquifero dell\u2019acqua trattata; b) esso \ue8 associato solitamente con costi elevati (pompaggio, materiali e reattivi); c) tali costi sono particolarmente sfavorevoli quando il P&T deve rimanere in funzione per un lungo periodo, come quando la presenza dei contaminati in acqua \ue8 controllata dalla lenta cinetica di dissoluzione del DNAPL. D\u2019altra parte, i processi oggi usati per il trattamento on site di acque sotterranee contaminate sono spesso un adattamento di processi gi\ue0 sviluppati per le acque di scarico industriali. Per i composti clorurati, \ue8 prevalente il trattamento con carbone attivo (diretto o previo stripping in corrente gassosa), caratterizzato da un costo di gestione molto alto e dalla necessit\ue0 di un post trattamento termico per ottenere la reale distruzione del contaminate clorurato. Permane perci\uf2 l\u2019interesse per processi P&T innovativi ed avanzati, che consentano la completa degradazione dei contaminanti (invece di un semplice trasferimento di fase) e siano efficienti, economici e robusti. In questo contesto, grande attenzione \ue8 stata anche rivolta al risanamento in situ, in cui il processo \ue8 condotto direttamente nell\u2019acquifero, agendo sul pennacchio di contaminazione o sulla sorgente di contaminazione. La maggior parte della ricerca scientifica si \ue8 concentrata su processi quali le barriere permeabili reattive, i processi biologici di declorazione riduttiva o ossidativa, l'ossidazione chimica in situ. Questi trattamenti offrono potenziali vantaggi per costi di gestione pi\uf9 bassi, minore richiesta energetica, assenza di effluenti da trattare e scaricare, minor disturbo dell\u2019uso del terreno. D\u2019altra parte, i trattamenti in situ chimici o biologici possono causare una contaminazione secondaria (accumulo di intermedi e prodotti tossici) e presentare difficolt\ue0 nel raggiungere le concentrazioni limite. Inoltre, richiedono un\u2019approfondita conoscenza delle condizioni ambientali mentre non sono…
Ion exchange represents one of the most promising processes for ammonium recovery from municipal ... more Ion exchange represents one of the most promising processes for ammonium recovery from municipal wastewater (MWW). However, most previous studies on ammonium ion exchange did not optimize the process or evaluate its robustness under real operational conditions. This experimental study aimed at (i) developing a procedure for the selection of a sorbent for selective ammonium removal/recovery from MWW, (ii) validating the procedure by applying it to several sorbents, (iii) performing a preliminary optimization and robustness assessment of ammonium removal/recovery with the selected sorbent. The application of the procedure to natural and synthetic zeolites and a cation exchange resin confirmed that batch isotherm tests need to be integrated by continuous-flow tests. The selected sorbent, a natural mixture of Chabazite and Phillipsite, resulted in high performances in terms of cation exchange capacity (33 mg N g dry resin − 1), ammonium operating capacity (5.2 mg N g dry resin − 1), ammonium recovery yield (78-91%) and selectivity towards ammonium. The process performances resulted stable during 7 adsorption/desorption cycles conducted with MWW treatment plant effluents in a 60-cm column. The switch to a highly saline effluent produced in a hotspot of seawater intrusion did not determine significant changes in performances. Contact time was reduced to 6 min without any decrease in performances. Potassiumwell tolerated by cropswas selected as the regenerating agent, in the perspective to produce a desorbed product to be re-used as fertilizer. The study shows that Chabazite/Phillipsite has a high capacity to recover ammonium from MWW in a circular economy approach.
Among the available technologies for ammonium removal from wastewater, ion exchange represents on... more Among the available technologies for ammonium removal from wastewater, ion exchange represents one of the most promising ones in the perspective to recover ammonium and produce a fertilizing product. However, the vast majority of previous studies on ammonium ion exchange did not evaluate the process robustness under real operational conditions nor optimized the desorption step. In this paper, tests of ammonium removal and recovery were conducted on a metakaolin K-based geopolymer, compared with a high-performing Italian natural zeolite in K-form. Real municipal and saline wastewater was treated in a continuous flow pilot plant equipped with a 60-cm adsorption bed (bed volume 203 mL, sorbent mass 145-173 g, empty bed contact time 10 minutes). Geopolymer granules showed higher performances in terms of selectivity towards ammonium, operating capacity (8.5 mgN g-1 dry adsorbent at an inlet concentration of 40 mgN L-1), bed volumes of wastewater treated at the selected breakpoint (149). Geopolymer resulted to be a cost-effective adsorbent for wastewater treatment capable to adsorb cations by ion exchange, allowing a fractionated desorption procedure that led to recover ammonium in a solution composed mainly by NH4NO3 (37%wt) and KNO3 (56%wt), potentially usable as fertilizer. The geopolymer robustness was assessed after repeated adsorption/regeneration cycles showing that the geopolymer mechanical and morphological properties did not deteriorate. The results make the tested geopolymer a very promising material for the optimization and scale-up of the ammonium recovery process in a circular economy perspective.
Convegno GRICU 2012 - Ingegneria Chimica: dalla nanoscala alla macroscala, 2012
La biodegradazione aerobica cometabolica di cloroformio ad opera di un consorzio batterico butano... more La biodegradazione aerobica cometabolica di cloroformio ad opera di un consorzio batterico butano-utilizzatore \\ue8 stata studiata per 1 anno in un reattore a colonna riempito con sabbia rappresentativo di una porzione di acquifero. Obiettivi dello studio erano: a) sviluppare l\\u2019alimentazione pulsata di substrato e ossigeno; b) testare e calibrare un modello cinetico di cometabolismo aerobico combinato con un modello fluidodinamico 1-D con dispersione; c) sviluppare una procedura numerica di calibrazione del modello (una variante del metodo di Gauss-Newton). L\\u2019applicazione di 6 tipologie di alimentazione pulsata ha consentito l\\u2019individuazione di un programma di pulsazione efficace nell\\u2019evitare l\\u2019intasamento del mezzo e in grado di garantire soddisfacenti prestazioni di degradazione del cloroformio
9th Euroepan Congress of Chemical Engineering / 2nd European Congress of Applied Biotechnology, 2013
BACKGROUND. Bio-hydrogen production from organic residues is an attractive process that combines ... more BACKGROUND. Bio-hydrogen production from organic residues is an attractive process that combines energy generation with waste treatment. This work represents the continuation of a previous study of biological H2 production from food industry wastes (Cappelleti et al., J. Chem. Technol. Biotechnol. 87:1291-1301), where the comparison of four thermophilic Thermotoga strains and four carriers for biomass immobilization led to the identification of T. neapolitana as the best-performing strain and of a porous ceramic material named Biomax as the best-performing support for biofilm formation. AIMS. The goals of this work were: a) to develop and calibrate a kinetic model of H2 production from glucose, molasses and cheese whey by suspended and attached cells of T. neapolitana, and b) to set-up and optimize a continuous-flow process of H2 production from cheese whey by T. neapolitana in a 20-L stirred reactor. METHODS. The experimental H2 rates used to develop the kinetic model were obtained from suspended- and attached-cell batch tests conducted in 120-mL bioreactors, exposed to different initial concentrations of glucose, molasses or cheese whey (0.1-95 g L-1, as total sugars). The process was scaled-up in a 20-L fermentor, fed only with cheese whey in consideration of the significantly higher production of this waste in Northern Italy, in comparison with molasses. The fermentor was operated initially with suspended-cells, and subsequently with attached-cells. To immobilize T. neapolitana in the fermentor, 5 L of the previously selected carrier were introduced in pockets made with steel net and fixed to the top and bottom of the vessel. RESULTS. The H2 specific production rates obtained with suspended and attached cell tests of T. neapolitana are shown in Figure 1, together with the best fitting simulations performed with the Haldane substrate inhibition model. The corresponding values of the kinetic parameters are reported in Table 1. For all the substrates studied, a marked substrate inhibition was noticed. The attached-cell tests resulted in higher rates than the suspended-cell ones, in particular in the case of glucose and molasses. Further tests indicated the absence of oxygen inhibition (studied range: 0-1% in the headspace, or 0-0.21 mgdissolved O2 L-1) and of product (H2) inhibition (studied range: 0-60% in the headspace, or 0-0.73 mgdissolved H2 L-1). The batch tests of H2 production from cheese whey conducted in the 20-L fermentor led to a productivity of 6.8 mmolH2 L-1 day-1 with suspended cells, and 22.5 mmolH2 L-1 day-1 with attached cells. The fermentor was also operated with attached cells in continuous-flow mode, with hydraulic retention times (HRT) in the 0.8-2.9 day range. The resulting H2 productivity showed an increasing trend with decreasing HRT, with a maximum value of 125 mmolH2 L-1 day-1. CONCLUSIONS. The calibration of a model of thermophilic H2 production from different wastes and the successful scale-up of the process of cheese whey conversion into H2 in a continuous-flow 20-L bioreactor pose the basis for a model-based optimization of the attached-cell process, and for its further scale-up to a pilot plant
INCA–Interuniv. Consortium Chemistry for Environ., 2005
Chlorinated aliphatic hydrocarbons (CAHs) are widespread, toxic and recalcitrant subsurface conta... more Chlorinated aliphatic hydrocarbons (CAHs) are widespread, toxic and recalcitrant subsurface contaminants. Among the different remediation options for CAH-contaminated sites, aerobic bioremediation represents a very interesting one, thanks to the high depletion rates achievable, the possibility to transform several CAHs into non-toxic, easily biodegradable compounds and the limited excavation works required. In most cases, the aerobic bioremediation of a CAH-polluted site can be performed only by means of cometabolism, which requires the supply of a suitable growth substrate. Cometabolic bioremediation is a rather complex process, whose outcome is not predictable on the basis of a mere site characterization: it is therefore necessary to perform a previous feasibility study. In several cases, the biological process can be significantly speeded up by means of the addition of previously selected microbial inocula. Despite the significant progresses made during the last years, the aerobic bioremediation of CAH-contaminated sites is not yet a widespread remediation technology
7th International Conference on Environmental Engineering and Management, 2013
Chlorinated aliphatic hydrocarbons (CAHs) are widespread groundwater contaminants. Aerobic cometa... more Chlorinated aliphatic hydrocarbons (CAHs) are widespread groundwater contaminants. Aerobic cometabolism, that requires the supply of a suitable growth substrate, represents an interesting option for the remediation of CAH-contaminated aquifers, thanks to its capability to lead to the complete mineralization of a very wide range of CAHs. The aim of this study was to develop and validate a procedure relative to the lab-scale tests required to obtain the essential information for the design of a process of CAH aerobic cometabolism in a packed bed reactor (PBR). To validate the procedure, the latter was applied to the development of a PBR process for the on-site aerobic cometabolism of an aquifer contaminated by trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (TeCA). The specific goals of this study, corresponding to the main steps of the above-mentioned procedure, were: (i) to select the best growth substrate for the aerobic cometabolic process, and to develop and characterize an effective CAH-degrading microbial consortium, obtained from the site\u2019s indigenous biomass by exposition to the selected substrate; (ii) to select the best carrier for the PBR process, and to evaluate the effect of bacterial adhesion on the developed suspended-cell consortium; and (iii) to identify and test suitable chemical-physical remediation alternatives in the case of presence of CAHs poorly biodegradable through AC. With regard to the growth substrate selection, the comparison of the CAH degradation performances obtained with 5 candidate substrates (methane, propane, butane, pentane and phenol) led to the selection of butane and to the development from the site\u2019s indigenous biomass of a suspended-cell consortium capable to degrade TCE (TCE first-order constant (k1,TCE) = 96 L gprotein-1 d-1 at 30 \ub0C and 4.3 L gprotein-1 d-1 at 15 \ub0C) with a 90% mineralization of the organic Cl. Based on PCR-DGGE analysis of the 16S rRNA genes followed by band excision and sequencing, the microbial consortium enriched was mainly composed of Bacteroidetes and Alpha- and Beta-Proteobacteria that were distantly related to known CAH-cometabolizing bacteria. With regard to the selection of the best-performing biofilm carrier, a preliminary screening based on the previous experience of the research group led to the pre-selection of four candidate biofilm carriers (porous materials specifically designed for biofilm processes): Biomax, Biomech, Biopearl and Cerambios. The choice of the best-performing carrier was made by means of a 2-level procedure. The 1st level consisted of batch tests, operated both at 30 and 15 \ub0C, whereas the 2nd level consisted of continuous-flow tests, operated at 30 \ub0C. The 30 \ub0C continuous-flow tests were conducted in four 1 L packed columns, connected to a feeding system designed so as to attain a pulsed feed of both oxygen and the selected growth substrate (butane). The four columns were operated in continuous mode for about 100 days. The results of the attached-cell tests were compared on the basis of the TCE normalized degradation rate ( and ) and of the attached cell concentration attained, at the two temperatures, at the end of the biofilm development process. On the basis of both the batch and the continuous-flow tests, Biomax resulted the best-performing biofilm carrier. Biomass immobilization on the carrier changed remarkably the structure of the microbial consortium. The effect on k1,TCE of biomass attachment depended on temperature: at 15 \ub0C the attached consortium performed slightly better than the suspended one, whereas at 30 \ub0C an opposite trend was noticed. On the basis of a 1st-order simulation, a 99.9% TCE conversion can be attained, at the site\u2019s temperature, with a 9-hour HRT. Lastly, the low TeCA degradation rate by the developed consortium suggested the introduction of a chemical pre-treatment based on the TeCA to TCE conversion via \uf062-elimination, a very fast reaction at alkaline pH. On the basis of the overall results, the procedure for the development of a PBR AC process appears to be correctly designed and generally applicable to CAH contaminated sites
Ecomondo 05. IV conferenza: Aspetti procedurali ed innovazione (bio)tecnologica nella gestione e bonifica dei siti contaminati, 2005
L\u2019obiettivo di questo lavoro \ue8 stato lo studio del processo di biodegradazione aerobica c... more L\u2019obiettivo di questo lavoro \ue8 stato lo studio del processo di biodegradazione aerobica cometabolica dell\u20191,1,2,2-tetracloroetano (TeCA) ad opera di biomasse metanotrofe e propanotrofe. La sperimentazione \ue8 stata condotta in microcosmi allestiti sia in condizioni slurry che, limitatamente alla biomassa propanotrofa, liquido/gas. I risultati indicano che il TeCA pu\uf2 essere biodegradato tramite cometabolismo aerobico ad opera sia di biomasse metano-utilizzatrici che propano-utilizzatrici nell\u2019intervallo 0-600 mg/l aq., e che tale processo pu\uf2 essere protratto per parecchi mesi senza che si verifichino fenomeni di inattivazione o danneggiamento delle biomasse oggetto di studio. Il trattamento di bioaugmentation ha consentito di ridurre drasticamente il lag-time per l\u2019avvio del processo degradativo cometabolico. I risultati positivi ottenuti nei microcosmi liquido/gas dimostrano che, a partire da pochi ml di biomassa propano-utilizzatrice sviluppata nei microcosmi slurry, \ue8 possibile produrre elevati quantitativi di inoculo tramite un processo di crescita in bioreattori non contenenti terreno, senza che si verifichino significative diminuzioni dell\u2019efficacia dell\u2019inoculo nella degradazione del TeCA
The goal of this study was to develop a mesophilic anaerobic co-digestion (co-AD) process of oliv... more The goal of this study was to develop a mesophilic anaerobic co-digestion (co-AD) process of olive mill wastewater (OMW) and sewage sludge (SwS) from municipal wastewater treatment. Different volumetric OMW:SwS ratios up to 100% OMW were fed in continuous 1.7-L bioreactors. The reactors fed with raw OMW (rOMW) performed better than those fed with OMW dephenolized by adsorption (dOMW). At a 23-day hydraulic retention time (HRT) the best performances were obtained in the reactor fed with 25% rOMW, with a 105% increase in methane yield in comparison to the 100% SwS test. At a 40-day HRT, the reactor fed with 40% rOMW attained a 268 NLCH4/kgVS methane yield (144% increase in comparison to 100% SwS). These results prove the feasibility of co-digesting with SwS the entire OMW production in regions characterized by intense olive oil production, with a strong increase in methane production.
BACKGROUND: Olive mill wastewaters (OMWs) represent a major environmental concern due to their hi... more BACKGROUND: Olive mill wastewaters (OMWs) represent a major environmental concern due to their high organic load and phytotoxic activity. The selective recovery of phenolic compounds (PCs) from OMW is promising, thanks to the antioxidant and antimicrobial properties of PCs. The goal of this work was to perform the life cycle assessment (LCA) and cost-benefit analysis (CBA) of a fullscale process of PC adsorption/desorption on resin Amberlite XAD16N. The industrial process was designed on the basis of laboratory tests aimed at performing a preliminary process optimization. RESULTS: Adsorption tests were conducted at different velocities in a 1.8-m column packed with XAD16N. The optimal superficial velocity and retention time (2.78 m/h and 0.56 h) allowed the attainment of satisfactory performances in terms of resin operating capacity (0.46), PC adsorption yield (0.92), PC mass fraction in the sorbed product (0.50 gPC/gVS) and specific antioxidant activity (3-6 gascorbic acid/gPC). Si...
The objective of this work was to study a process of 1,1,2,2-tetrachloroethane (TeCA) biodegradat... more The objective of this work was to study a process of 1,1,2,2-tetrachloroethane (TeCA) biodegradation via aerobic cometabolism by methane-utilizing and propane-utilizing microbial cultures. Both cultures were studied by means of slurry microcosm tests; the propane-utilizing culture was further studied in liquid/gas bioreactors. TeCA was biodegraded by both microbial cultures via aerobic cometabolism in the 0-600 μg/L concentration range. The process was successfully continued for several months without any apparent inhibitory or toxic effect on the microbial cultures tested. In bioaugmented microcosms, the inoculation of the propane-utilizing culture developed in the slurry microcosms led to a marked reduction of the lag-period required for the onset of TeCA degradation. The positive results obtained from the liquid/gas reactors show that it is possible to grow the isolated propane-utilizing culture in a liquid/gas bioreactor without any observable loss of TeCA degradation capacity. This conclusion is relevant with respect to the production of significant amounts of inoculum to utilize in bioaugmentation treatments
Extreme weather and climate change policy failures are the greatest threats the world is facing o... more Extreme weather and climate change policy failures are the greatest threats the world is facing over the next 10 years. The Middle East and North Africa (MENA) region is the driest area in the world and is already affected by desertification, groundwater over-exploitation, and seawater intrusion into aquifers. The consequences of climate change for water security in MENA will be amplified given that the expected population growth and economic growth is projected to result in a 47 % increase in water demand by 2035.
A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from ... more A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from PC-rich wastes and wastewaters was innovatively proposed and applied to compare 4 neutral resins (Amberlite XAD 16, Optipore SD-2, Amberlite FPX66, Amberlite XAD761) and 1 ion-exchange resin (IRA958 Cl) for PC recovery from a Tunisian olive mill wastewater (OMW).
Il risanamento di siti contaminanti \ue8 divenuto una delle pi\uf9 importanti emergenze ambiental... more Il risanamento di siti contaminanti \ue8 divenuto una delle pi\uf9 importanti emergenze ambientali, sia in Italia che in Europa. Il documento preparatorio per una futura possibile Direttiva Europea sulla \u201cProtezione del Suolo\u201d (Proposta COM2006/232) stima che 3.5 milioni di siti potenzialmente contaminanti dovranno essere individuati e caratterizzati in Europa, con un costo di circa 240 milioni di \u20ac per almeno 25 anni. La Proposta stima che circa 500.000 siti contaminati dovranno poi essere effettivamente risanati. In Italia esistono gi\ue0 57 siti contaminati di interesse nazionale (700.000 ha, pi\uf9 del 2% del territorio nazionale, Legge n.426/1998 e s.m.i), per i quali esiste un finanziamento pubblico di circa 750 milioni \u20ac, destinato principalmente alla messa in sicurezza di emergenza. Inoltre, si stima che circa 15.000 siti contaminati di interesse locale dovranno essere caratterizzati e forse bonificati, con un costo di circa 25-30 miliardi di \u20ac nei prossimi 15 anni. Il primo recettore della contaminazione del sito \ue8 solitamente l'acqua sotterranea al di sotto del sito stesso, da cui la contaminazione pu\uf2 facilmente migrare verso altri recettori, incluso l\u2019uomo. L\u2019acqua sotterranea \ue8 un recettore molto sensibile, essendo una risorsa importante e limitata, i cui usi reali e potenziali sono ostacolati persino da bassi livelli di contaminazione. Tra i contaminanti di un\u2019acqua sotterranea, i composti clorurati sono certamente i pi\uf9 diffusi: l\u2019Helmholtz Center for Environmental Research della Germania stima che i composti clorurati (principalmente tetracloroetilene e tricloroetilene, PCE e TCE) siano presenti in pi\uf9 del 50% dei casi. Essi sono anche pericolosi dal punto di vista ambientale ed igienico-sanitario, in quanto a) la maggior parte di essi sono altamente tossici e sospetti cancerogeni, b) sono in grado di formare fasi separate, spesso con densit\ue0 maggiore dell\u2019acqua (DNAPL) e quindi c) permangono a concentrazioni pi\uf9 alte e per un periodo pi\uf9 lungo rispetto ad altri contaminanti. Quando una falda acquifera \ue8 contaminata, l\u2019Autorit\ue0 Pubblica richiede di solito misure di messa in sicurezza d\u2019emergenza, per evitare l\u2019espansione della contaminazione verso recettori sensibili. Tali misure sono generalmente attuate attraverso barriere passive (diaframmi impermeabili con trincee di drenaggio) o dinamiche (barriere idrauliche), il che comporta l\u2019attivazione di un sistema di depurazione \u201con site\u201d dell\u2019acqua estratta (\u201cpump-and-treat\u201d, P&T). Il grande sviluppo dei sistemi P&T \ue8 dovuto anche alla relativa facilit\ue0 di gestione e alla consolidata esperienza acquisita negli anni. Tuttavia, il P&T presenta diversi svantaggi: a) esso non preserva l\u2019acqua di falda come risorsa quantitativa potenzialmente disponibile per l\u2019uomo poich\ue9 spesso non \ue8 possibile (per vari motivi) la re-introduzione dell\u2019acquifero dell\u2019acqua trattata; b) esso \ue8 associato solitamente con costi elevati (pompaggio, materiali e reattivi); c) tali costi sono particolarmente sfavorevoli quando il P&T deve rimanere in funzione per un lungo periodo, come quando la presenza dei contaminati in acqua \ue8 controllata dalla lenta cinetica di dissoluzione del DNAPL. D\u2019altra parte, i processi oggi usati per il trattamento on site di acque sotterranee contaminate sono spesso un adattamento di processi gi\ue0 sviluppati per le acque di scarico industriali. Per i composti clorurati, \ue8 prevalente il trattamento con carbone attivo (diretto o previo stripping in corrente gassosa), caratterizzato da un costo di gestione molto alto e dalla necessit\ue0 di un post trattamento termico per ottenere la reale distruzione del contaminate clorurato. Permane perci\uf2 l\u2019interesse per processi P&T innovativi ed avanzati, che consentano la completa degradazione dei contaminanti (invece di un semplice trasferimento di fase) e siano efficienti, economici e robusti. In questo contesto, grande attenzione \ue8 stata anche rivolta al risanamento in situ, in cui il processo \ue8 condotto direttamente nell\u2019acquifero, agendo sul pennacchio di contaminazione o sulla sorgente di contaminazione. La maggior parte della ricerca scientifica si \ue8 concentrata su processi quali le barriere permeabili reattive, i processi biologici di declorazione riduttiva o ossidativa, l'ossidazione chimica in situ. Questi trattamenti offrono potenziali vantaggi per costi di gestione pi\uf9 bassi, minore richiesta energetica, assenza di effluenti da trattare e scaricare, minor disturbo dell\u2019uso del terreno. D\u2019altra parte, i trattamenti in situ chimici o biologici possono causare una contaminazione secondaria (accumulo di intermedi e prodotti tossici) e presentare difficolt\ue0 nel raggiungere le concentrazioni limite. Inoltre, richiedono un\u2019approfondita conoscenza delle condizioni ambientali mentre non sono…
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