Combined thoracic erector spinae plane and inter-transverse plane blocks for awake breast surgery.

Worldwide, breast cancer is the most commonly diagnosed cancer in women. Surgical procedures are typically performed using general anaesthesia, often complemented by regional anaesthesia to manage postoperative pain. However, avoidance of general anaesthesia for breast surgery may be desirable for clinical reasons or patient choice. It is theorised that the use of regional anaesthesia and the avoidance of volatile anaesthetics and opioid analgesia may have beneficial effects on oncological outcomes, and there is some evidence to support this. While many patients successfully undergo awake breast surgery, a limited number of anaesthetists possess direct experience of this approach, despite familiarity with regional anaesthesia techniques. Undertaking regional anaesthesia for awake breast surgery requires patient cooperation and excellent staff teamwork. Here, we present a case of a patient who underwent awake bilateral mastectomy with reconstruction. This was carried out under two 'paravertebral-by-proxy' blocks: the thoracic erector spinae plane and inter-transverse plane blocks, with intravenous sedation.

Unilateral sacral erector spinae plane block for hip fracture surgery.

The provision of anaesthesia for hip fracture surgery in elderly and frail patients can be challenging, with potentially significant risks associated with both general and neuraxial techniques. Here, we report the use of a sacral erector spinae plane block as an alternative to conventional anaesthetic approaches for a frail 89-year-old woman with significant cardiovascular and respiratory comorbidity who underwent intramedullary nailing for a proximal femoral fracture. A unilateral injection of local anaesthetic at the intermediate crest of the second sacral vertebra resulted in bilateral sensory block of the T12 to S2 dermatomes. The technique did not result in hypotension or motor block of the limbs, and the surgery was completed uneventfully. Sacral erector spinae plane block warrants further investigation as an alternative to spinal and general anaesthesia for hip and lower limb surgery.

Techno-environmental and economic assessment of color removal strategies from textile wastewater.

The textile industry is one of the most chemical-intensive processes, resulting in the unquestionable pollution of more than a quarter of the planet's water bodies. The high recalcitrant properties of some these pollutants resulted on the development of treatment technologies looking at the larger removal efficiencies, due to conventional systems are not able to completely remove them in their effluents. However, safeguarding the environment also implies taking into account indirect pollution from the use of chemicals and energy during treatment. On the other hand, the emerged technologies need to be economically attractive for investors and treatment managers. Therefore, the costs should be kept under control. For this reason, the present study focuses on a comparative Life Cycle Assessment and Life Cycle Costing of four scale-up scenarios aiming at mono and di-azo reactive dyes removal from textile wastewater. Two reactors (sequencing batch reactor and two-phase partitioning) were compared for different reaction environments (i.e., single anaerobic and sequential anaerobic-aerobic) and conditions (different pH, organic loading rates and use of polymer). In accordance with the results of each scenario, it was found that the three technical parameters leading to a change in the environmental profiles were the removal efficiency of the dyes, the type of dye eliminated, and the pollutant influent concentration. The limitation of increasing organic loading rates related to the biomass inhibition could be overcame through the use of a novel two-phased partitioning bioreactor. The use of a polymer at this type of system may help restore the technical performance (84.5 %), reducing the toxic effects of effluents and consequently decreasing the environmental impact. In terms of environmental impact, this is resulting into a reduction of the toxic effects of textile effluents in surface and marine waters compared to the homologous anaerobic-aerobic treatment in a sequencing batch reactor. However, the benefits achieved for the nature comes with an economic burden related to the consumption of the polymer. It is expected that the cost of investment of the treatment with the two-phase partitioning bioreactor rises 0.6-8.3 %, depending on market prices, compared to the other analyzed sequential anaerobic-aerobic technologies. On the other side, energy and chemical consumption did not prove to be limiting factors for economic feasibility.

Eficacia analgésica del bloqueo del grupo de nervios pericapsulares (PENG) en comparación con el bloqueo de la fascia ilíaca (FIB) en pacientes mayores con fractura de fémur proximal en la unidad de urgencias. Ensayo controlado aleatorizado / Analgesic efficacy of Pericapsular Nerve Group (PENG) block compared with Fascia Iliaca Block (FIB) in the elderly patient with fracture of the proximal femur in the emergency room. A randomised controlled trial

Introducción y objetivos: Son escasos los datos relativos a la eficacia del bloqueo PENG (grupo de nervios pericapsulares) para el dolor por traumatismo de cadera. Formulamos la hipótesis de que el bloqueo PENG era más efectivo que el bloqueo FIB (fascia ilíaca) ecoguiado (infrainguinal) para controlar el dolor en los pacientes de 65 o más, con fractura de fémur proximal traumática en la unidad de urgencias hospitalarias (UUH). Materiales y métodos Realizamos un ensayo controlado aleatorizado exploratorio y doble ciego, siendo diferentes el anestesiólogo que realizó el bloqueo y el que evaluó los resultados. Se asignó aleatoriamente a los pacientes al grupo PENG con 20ml de ropivacaína al 0,375% o al grupo FIB (infrainguinal) con 40ml de ropivacaína al 0,2%. Se realizaron las pruebas de hipótesis estándar (prueba t o prueba χ2) para analizar las características basales y los parámetros del resultado. El objetivo primario del estudio fue el éxito analgésico de PENG evaluado como «puntuación NRS de dolor incidental≤4» 30min tras la colocación del bloqueo en comparación con FIB, también a los 30min del bloqueo. Los objetivos secundarios fueron el dolor en reposo («puntuación NRS de dolor en reposo≤4» 30min tras la colocación de los bloqueos), la duración de los bloqueos (tiempo transcurrido antes de la primera solicitud de analgesia del paciente), incidencia de administración de medicación de rescate en caso de fracaso del bloqueo, complicaciones relativas a la colocación del bloqueo. Resultados Tras la obtención de la aprobación del comité ético y el consentimiento informado escrito, se incluyó a 60 pacientes. Considerando el resultado primario, se logró el objetivo en el grupo PENG en 16 de entre 30 pacientes (53,3%), y en 15 de entre 28 casos en el grupo FIB (53,6%). La comparación entre ambos grupos no demostró la superioridad del bloqueo PENG frente a FIB (valor p=0,98). Conclusiones El bloqueo PENG no es superior ... . (AU)

Introduction and objectives: Data on the efficacy of PENG (Pericapsular Nerve Group) block in hip trauma pain are scarce. We hypothesized that PENG block was more effective than infra-inguinal ultrasound-guided FIB (Fascia Iliaca block) for pain control in patients aged 65 years or older presenting in the emergency room (ER) with traumatic proximal femoral fracture. Materials and methods We conducted an exploratory, double-blind, randomized controlled trial. One anaesthesiologist performed the block and another assessed outcomes. Patients were randomly allocated to the PENG group (20ml ropivacaine 0.375%) or the infrainguinal FIB group (40ml ropivacaine 0.2%). Standard hypothesis tests (t test or χ2 test) were performed to analyse baseline characteristics and outcome parameters. The primary end-point of the study was analgesic success, defined as «NRS pain score≤4» 30min after blockade, with PENG vs to FIB. Secondary outcomes were pain at rest («pain at rest NRS score≤4» 30min after blockade), duration of analgesia (time to first request for analgesia), need for rescue medication in case of block failure, and complications during blockade. Results After obtaining ethical committee approval and written informed consent, 60 patients were included.The primary endpoint was achieved in 16 out of 30 patients (53.3%) in the PENG group and in 15 out of 28 patients (53.6%) in the FIB group. Comparison between groups did not show superiority of the PENG vs FIB (p=0.98). Conclusions PENG block does not provide better pain than FIB in proximal femoral fracture in elderly patients treated in the ER. (AU)

Analgesic efficacy of Pericapsular Nerve Group (PENG) block compared with Fascia Iliaca Block (FIB) in the elderly patient with fracture of the proximal femur in the emergency room. A randomised controlled trial.

INTRODUCTION AND OBJECTIVES: Data on the efficacy of PENG (Pericapsular Nerve Group) block in hip trauma pain are scarce. We hypothesized that PENG block was more effective than infra-inguinal ultrasound-guided FIB (Fascia Iliaca block) for pain control in patients aged 65 years or older presenting in the emergency room (ER) with traumatic proximal femoral fracture. MATERIALS AND METHODS: We conducted an exploratory, double-blind, randomized controlled trial. One anaesthesiologist performed the block and another assessed outcomes. Patients were randomly allocated to the PENG group (20 ml ropivacaine 0.375%) or the infrainguinal FIB group (40 ml ropivacaine 0.2%). Standard hypothesis tests (t test or χ2 test) were performed to analyse baseline characteristics and outcome parameters. The primary end-point of the study was analgesic success, defined as "NRS pain score ≤ 4" 30 min after blockade, with PENG vs to FIB. Secondary outcomes were pain at rest ("pain at rest NRS score ≤ 4" 30 min after blockade), duration of analgesia (time to first request for analgesia), need for rescue medication in case of block failure, and complications during blockade. RESULTS: After obtaining ethical committee approval and written informed consent, 60 patients were included. The primary endpoint was achieved in 16 out of 30 patients (53.3%) in the PENG group and in 15 out of 28 patients (53.6%) in the FIB group. Comparison between groups did not show superiority of the PENG vs FIB (P-value .98). CONCLUSIONS: PENG block does not provide better pain than FIB in proximal femoral fracture in elderly patients treated in the ER.

Artificial intelligence-based radiomics on computed tomography of lumbar spine in subjects with fragility vertebral fractures.

PURPOSE: There is emerging evidence that radiomics analyses can improve detection of skeletal fragility. In this cross-sectional study, we evaluated radiomics features (RFs) on computed tomography (CT) images of the lumbar spine in subjects with or without fragility vertebral fractures (VFs). METHODS: Two-hundred-forty consecutive individuals (mean age 60.4 ± 15.4, 130 males) were evaluated by radiomics analyses on opportunistic lumbar spine CT. VFs were diagnosed in 58 subjects by morphometric approach on CT or XR-ray spine (D4-L4) images. DXA measurement of bone mineral density (BMD) was performed on 17 subjects with VFs. RESULTS: Twenty RFs were used to develop the machine learning model reaching 0.839 and 0.789 of AUROC in the train and test datasets, respectively. After correction for age, VFs were significantly associated with RFs obtained from non-fractured vertebrae indicating altered trabecular microarchitecture, such as low-gray level zone emphasis (LGLZE) [odds ratio (OR) 1.675, 95% confidence interval (CI) 1.215-2.310], gray level non-uniformity (GLN) (OR 1.403, 95% CI 1.023-1.924) and neighboring gray-tone difference matrix (NGTDM) contrast (OR 0.692, 95% CI 0.493-0.971). Noteworthy, no significant differences in LGLZE (p = 0.94), GLN (p = 0.40) and NGDTM contrast (p = 0.54) were found between fractured subjects with BMD T score < - 2.5 SD and those in whom VFs developed in absence of densitometric diagnosis of osteoporosis. CONCLUSIONS: Artificial intelligence-based analyses on spine CT images identified RFs associated with fragility VFs. Future studies are needed to test the predictive value of RFs on opportunistic CT scans in identifying subjects with primary and secondary osteoporosis at high risk of fracture.

Extractive membrane bioreactor to detoxify industrial/hazardous landfill leachate and facilitate resource recovery.

Landfill leachate is a highly polluted and toxic waste stream harmful to the environment and human health, its biological treatment, even if challenging, offers the opportunity of recovering valuable resources. In this study, we propose the application of an extractive membrane bioreactor equipped with a polymeric tubing, made of Hytrel, as an innovative device able to remove specific organic toxic compounds of the leachate and, at the same time, to produce an effluent rich in valuable chemicals suitable for recovery. The leachate treatment consists in a two-step process: the extraction of specific toxic compounds through the polymeric tubing based on the affinity with the polymer, and their subsequent biodegradation in controlled conditions in the bulk phase of the extractive membrane bioreactor, thus avoiding the direct contact of the microbial consortium with the toxic leachate. Three synthetic streams simulating leachates produced by landfills of typical industrial/hazardous waste, mixed municipal and industrial solid waste, and oil shale industry waste, whose toxic fraction is mainly constituted by phenolic compounds, have been tested. Successful performance was achieved in all the tested conditions, with high removal (≥98%) and biodegradation efficiencies (89-95%) of the toxic compounds. No mass transfer limitations across the tubing occurred during the operation and a marginal accumulation (in the range of 4-7%) into the polymer has been observed. Furthermore, volatile fatty acids and inorganic compounds contained in the leachates were fully recovered in the treated effluent. Feasibility study confirmed the applicability of the proposed bioreactor as a powerful technology able to achieve high toxic removal efficiency in leachate treatment and facilitate resource recovery.

Anaerobic biodegradation of phenol in wastewater treatment: achievements and limits.

Anaerobic biodegradation of toxic compounds found in industrial wastewater is an attractive solution allowing the recovery of energy and resources but it is still challenging due to the low kinetics making the anaerobic process not competitive against the aerobic one. In this review, we summarise the present state of knowledge on the anaerobic biodegradation process for phenol, a typical target compound employed in toxicity studies on industrial wastewater treatment. The objective of this article is to provide an overview on the microbiological and technological aspects of anaerobic phenol degradation and on the research needs to fill the gaps still hindering the diffusion of the anaerobic process. The first part is focused on the microbiology and extensively presents and characterises phenol-degrading bacteria and biodegradation pathways. In the second part, dedicated to process feasibility, anaerobic and aerobic biodegradation kinetics are analysed and compared, and strategies to enhance process performance, i.e. advanced technologies, bioaugmentation, and biostimulation, are critically analysed and discussed. The final section provides a summary of the research needs. Literature data analysis shows the feasibility of anaerobic phenol biodegradation at laboratory and pilot scale, but there is still a consistent gap between achieved aerobic and anaerobic performance. This is why current research demand is mainly related to the development and optimisation of powerful technologies and effective operation strategies able to enhance the competitiveness of the anaerobic process. Research efforts are strongly justified because the anaerobic process is a step forward to a more sustainable approach in wastewater treatment.Key points• Review of phenol-degraders bacteria and biodegradation pathways.• Anaerobic phenol biodegradation kinetics for metabolic and co-metabolic processes.• Microbial and technological strategies to enhance process performance.

Anaerobic phenol biodegradation: kinetic study and microbial community shifts under high-concentration dynamic loading.

The anaerobic biodegradation of phenol has been realised in a sequencing batch reactor (SBR) under anaerobic conditions with phenol as sole carbon and energy source and with glucose as co-substrate. A step-change increase of phenol loading (from 100 up to 2000 mg/L of phenol concentration in the feed solution) has been applied during the acclimation phase in order to progressively induce the development of a specialised microbial consortium. This approach, combined with the dynamic sequence of operations characterising SBRs and with the high biomass retention time, led to satisfactory phenol and COD removal efficiencies with values > 70% for the highest phenol input (2000 mg/L) fed as the single carbon and energy source. Analysis of removal efficiencies and biodegradation rates suggested that the use of glucose as co-substrate did not induce a significant improvement in process performance. Kinetic tests have been performed at different initial phenol (400-1000 mg/L) and glucose (1880-0 mg/L) concentrations to kinetically characterise the developed biomass: estimated kinetic constants are suitable for application and no inhibitory effect due to high concentrations of phenol has been observed in all investigated conditions. The microbial community has been characterised at different operating conditions through molecular tools: results confirm the successful adaptation-operation approach of the microbial consortium showing a gradual increase in richness and diversity and the occurrence and selection of a high proportion of phenol-degrading genera at the end of the experimentation. Key Points • Anaerobic phenol removal in the range of 70-99% in a sequencing batch reactor. • Negligible effect of co-substrate on removal efficiencies and biodegradation rates. • No biomass inhibition due to phenol concentration in the range of 400-1000 mg/L. • Increasing phenol loads promoted the culture enrichment of phenol-degrading genera.

Self-regenerating tubing bioreactor for removal of toxic substrates: Operational strategies in response to severe dynamic loading conditions.

A tubing TPPB (Two-Phase Partitioning Bioreactor) was operated with the objective of verifying the effective treatment of a phenolic synthetic wastewater with simultaneous polymeric tubing bioregeneration by introducing tubing effluent recycle and modifications to the Hydraulic Retention Time (HRT). 2,4-dichlorophenol (DCP) was employed as the target substrate and the bioreactor was operated for a 3 month period under severe loading conditions (from 77 to 384 mg/L d) with HRT in the tubing in the range of 2-4 h. Tubing effluent recycle (recycle flow rate/influent flow rate ratio = 0.3) was applied when a loss of performance was detected arising from the increased load. For HRT values of 3 and 4 h, almost complete DCP removal was achieved after a few days (1-5) of operation while for the 2 h HRT (i.e. in the most severe loading condition) the DCP removal was ≥97%. A beneficial effect on the process performance arising from recycle application was evident for all the operating conditions investigated, and was confirmed by statistical analysis. Essentially complete polymer bioregeneration was achieved when the bioreactor was operated at the lowest HRT (i.e. 2 h), combined with the application of tubing effluent recycle. The results of this study highlighted several advantages of the tubing TPPB configuration in a comparative analysis of different regeneration options, including the possibility of operating continuously with simultaneous bioregeneration and without the need for additional units or operational steps and extra-energy consumption.

Post-aerobic treatment to enhance the removal of conventional and emerging micropollutants in the digestion of waste sludge.

Low content of micropollutants in sewage sludge, essential to allow its safe re-use in agriculture, requires effective removals during the digestion phase. To this purpose, we investigated the performance of the anaerobic-aerobic sequential digestion process applied to real waste sludge in the removal of several classes of standard pollutants, i.e. extractable organic halogens (EOXs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), di(2-ethylhexyl)phthalate and alkylphenolethoxylates. In addition, emerging pollutants were also investigated based on their widespread occurrence and on their physicochemical characteristics and eco-toxicological relevance: quaternary ammonium compounds, a number of pharmaceuticals and selected biocides. The anaerobic step was conducted at mesophilic conditions, while two operating temperatures were tested for the post-aerobic treatment, i.e. 20 and 37 °C, respectively. Results showed that the post-aerobic digestion step enhanced the removal of all investigated standard and emerging micropollutants, even in presence of high accumulation in the anaerobic digestate (occurred for some PAHs and PCB congeners). Increased removals (up to 30%) have been generally observed at 37 °C aerobic temperature in comparison with tests at T = 20 °C for all investigated organic micropollutants, with the only exception of halogenated compounds (i.e. EOXs and PCBs). Low biodegradability and high bioaccumulation of the investigated pollutants were successfully faced by the sequential process, which has been demonstrated as an effective alternative solution to produce digested sludge for safe agricultural re-use.

Anaerobic-aerobic sequential treatment: Temperature optimization and cost implications.

Traditionally, aeration units, used as a polishing stage after anaerobic digestion (AD) of wastes, are operated at ambient temperature. Yet, when effluent quality is the main design criterion, raising the temperature of the aeration stage can be justified by improved removal efficiencies. In this study, an anaerobic-aerobic sequential system (AASS) was operated to co-digest raw wastewater and food waste. The aerobic compartment was tested under psychrophilic and mesophilic temperatures. At the design loading rate of 2 gVS L-1 d-1, the anaerobic digester achieved removal efficiencies of 85 ± 2% of volatile solids (VS), 84 ± 3% of total chemical oxygen demand (CODT) and a biogas yield of 1,035 ± 30 mL gVSfed-1 (50% methane). The aerobic reactor achieved additional removal of 8% CODT and 7 % VS. By raising the temperature of the aerobic reactor to the mesophilic range, COD and solids concentrations of the effluent dropped to approximately half their values. This was accompanied by an increase in nitrification (from 68% to 91%) and denitrification (from 10% to 16%). The energy analysis showed that total energy consumption slightly increases (from 0.45 to 0.49 kWh kgCODfed-1) by raising the temperature of the aerobic reactor to mesophilic range. A preliminary evaluation of the sludge disposal cost, revealed a saving increase of 5-6% under mesophilic operation with respect to psychrophilic conditions. Implications: In order to cope with the globally increasing constraints on the disposal of urban wastes, efficient post-processing of effluents becomes a crucial requirement for the anaerobic digestion industry. In this context, the submitted manuscript shows that the quality of the effluent, of an anaerobic digester, treating food waste with raw wastewater, can be substantially improved by optimizing the aerobic polishing stage. Raising the temperature of the aerobic reactor to the mesophilic range resulted in a drop of solids and COD concentrations to approximately half their values. Equally important, the implications on operational costs were found to be favorable, compared to traditional psychrophilic aerobic post-treatment, when taking into consideration indirect sludge treatment costs and energy selling revenues.

Polymer extraction and ex situ biodegradation of xenobiotic contaminated soil: Modelling of the process concept.

An integrated model of a two-step process for the ex situ bioremediation of xenobiotic contaminated soil has been formulated. The process is characterized by an initial extraction step of the organic contaminants from the polluted soil by contact with inexpensive and commercially-available polymer beads, followed by release and biodegradation of the xenobiotics, with parallel polymer bioregeneration, in a Two-Phase Partitioning Bioreactor (TPPB). The regenerated polymer is cyclically reused in the extraction step, so reflecting the robust and otherwise-inert properties of such polymers. The model was calibrated and validated for a soil contaminated with 4-nitrophenol (4NP) and treated with the DuPont polymer Hytrel 8206. In the model calibration, the partition coefficient polymer-soil, Pps, and the mass transfer coefficient, K, were evaluated, as 105.3 and 0.24 h-1 respectively. A diffusion coefficient within the polymer of 6.3 10-8 cm2 s-1 was determined from the fitting of sorption/desorption data. The model was then tested for two alternative process configurations consisting of either one or two soil extraction units, followed by the biodegradation/bioregeneration step. The latter configuration resulted in more effective polymer utilization and is suitable if each extraction step requires a shorter time than the regeneration step. The model predicted that an extraction time of 12 h was sufficient to reach removal efficiencies ≥90% while the biodegradation/bioregeneration step required 24 h to reach efficiencies ≥93%, with a good agreement with experimental data (R2 > 0.98 for both cases). The simulation of the process operated with two extraction units showed a better performance with a final concentration ∼0.2 g4NP kgds-1 vs. 1.69 g4NP kgds-1 obtained with single extraction unit, for a soil contaminated with 10 g4NP kgds-1. Corresponding extraction efficiencies were 96 and 83%, respectively.

On the applicability of a hybrid bioreactor operated with polymeric tubing for the biological treatment of saline wastewater.

Effective biological treatment of high salt content wastewater requires consideration of both salt and organic toxicity. This study treated a synthetic saline wastewater containing NaCl (100gL-1) and 2,4-dimethylphenol (1.2gL-1) with a hybrid system consisting of a biological reactor containing spiral-coiled polymeric tubing through which the mixed feed was pumped. The tubing wall was permeable to the organic contaminant, but not to the salt, which allowed transfer of the organic into the cell-containing bioreactor contents for degradation, while not exposing the cells to high salt concentrations. Different grades of DuPont Hytrel polymer were examined on the basis of organic affinity predictions and experimental partition and mass transfer tests. Hytrel G3548 tubing showed the highest permeability for 2,4-dimethylphenol while exerting an effective salt barrier, and was used to verify the feasibility of the proposed system. Very high organic removal (99% after just 5h of treatment) and effective biodegradation of the organic fraction of the wastewater (>90% at the end of the test) were observed. Complete salt separation from the microbial culture was also achieved.

A novel continuous two-phase partitioning bioreactor operated with polymeric tubing: Performance validation for enhanced biological removal of toxic substrates.

A continuous two-phase partitioning bioreactor (C-TPPB), operated with coiled tubing made of the DuPont polymer Hytrel 8206, was tested for the bioremediation of 4-chlorophenol, as a model toxic compound. The tubing was immersed in the aqueous phase, with the contaminated water flowing tube-side, and an adapted microbial culture suspended in the bioreactor itself, with the metabolic demand of the cells creating a concentration gradient to cause the substrate to diffuse into the bioreactor for biodegradation. The system was operated over a range of loadings (tubing influent concentration 750-1500 mg L-1), with near-complete substrate removal in all cases. Distribution of the contaminant at the end of the tests (96 h) highlighted biological removal in the range of 87-95%, while the amount retained in the polymer ranged from ∼1 to 8%. Mass transfer of the substrate across the tubing wall was not limiting, and the polymer demonstrated the capacity to buffer the substrate loadings and to adapt to microbial metabolism. The impact of C-TPPB operation on biomass activity was also investigated by a kinetic characterization of the microbial culture, which showed better resistance to substrate inhibition after C-TPPB operation, thereby confirming the beneficial effect of sub-inhibitory controlled conditions, characteristic of TPPB systems.

Sequential anaerobic-aerobic decolourization of a real textile wastewater in a two-phase partitioning bioreactor.

This work describes the application of a solid-liquid two-phase partitioning bioreactor (TPPB) for the removal of colour from a real textile wastewater containing reactive azo-dyes. Four polymers were tested over the pH range of 4-9 to select the most effective absorbant to be used as the partitioning phase in the TPPB. The best results were obtained with Hytrel 8206 at pH4 achieving ~70% colour removal, based on the dominant wavelength, in the first 5h of contact time, and 84% after 24h. Wastewater treatment was undertaken in a solid-liquid TPPB operated with Hytrel 8206 in sequential anaerobic-aerobic configuration. The reaction time of 23h was equally distributed between the anaerobic and aerobic phases and, to favour colour uptake, the pH was controlled at 4.5 in the first 4h of the anaerobic phase, and then increased to 7.5. Colour removal (for the dominant wavelength, 536nm) increased from 70 to 85% by modifying the bioreactor operation from single-phase to TPPB mode. Based on COD measurements nearly complete biodegradation of the intermediates produced in the anaerobic phase was obtained, both in the single-phase and two-phase mode, with better performance of the TPPB system reaching 75% CODDye removal.

Towards a continuous two-phase partitioning bioreactor for xenobiotic removal.

The removal of a xenobiotic (4-chlorophenol) from contaminated water was investigated in a simulated continuous two-phase partitioning bioreactor (C-TPPB), fitted with coiled tubing comprised of a specifically-selected extruded polymer, Hytrel 8206. Wastewater flowed inside the tubing, the pollutant diffused through the tubing wall, and was removed in the aqueous bioreactor phase at typical biological removal rates in the C-TTPB simulated by varying aqueous phase throughput to the reactor. Operating over a range of influent substrate concentrations (500-1500mgL(-1)) and hydraulic retention times in the tubing (4-8h), overall mass transfer coefficients were 1.7-3.5×10(-7)ms(-1), with the highest value corresponding to the highest tubing flow rate. Corresponding mass transfer rates are of the same order as biological removal rates, and thus do not limit the removal process. The C-TPPB showed good performance over all organic and hydraulic loading ranges, with removal efficiencies of 4CP in the tubing wastewater stream always ≥96%. Additionally, the presence of the Hytrel tubing was able to buffer increases in organic loading to the hybrid system, enhancing overall process stability. Biological testing of the C-TPPB confirmed the abiotic test results demonstrating even higher 4-chlorophenol removal efficiency (∼99%) in the tubing stream.

Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion.

Regeneration strategies of polymers employed in ex-situ remediation of contaminated soil: Bioregeneration versus solvent extraction.

In this study we evaluated the feasibility of two regeneration strategies of contaminated polymers employed for ex-situ soil remediation in a two-step process. Soil decontamination is achieved by sorption of the pollutants on the polymer beads, which are regenerated in a subsequent step. Tested soil was contaminated with a mixture of 4-chlorophenol and pentachlorophenol, and a commercial polymer, Hytrel, has been employed for extraction. Removal efficiencies of the polymer-soil extraction are in the range of 51-97% for a contact time ≤ 24 h. Two polymer regeneration strategies, solvent extraction and biological regeneration (realized in a two-phase partitioning bioreactor), were tested and compared. Performance was assessed in terms of removal rates and efficiencies and an economic analysis based on the operating costs has been performed. Results demonstrated the feasibility of both regeneration strategies, but the bioregeneration was advantageous in that provided the biodegradation of the contaminants desorbed from the polymer. Practically complete removal for 4-chlorophenol and up to 85% biodegradation efficiency for pentachlorophenol were achieved. Instead, in the solvent extraction, a relevant production (184-831 L kg(pol)(-1)) of a highly polluted stream to be treated or disposed of is observed. The cost analysis of the two strategies showed that the bioregeneration is much more convenient with operating costs of ∼12 €/kg(pol) i.e. more than one order of magnitude lower in comparison to ∼233 €/kg(pol) of the solvent extraction.