Two phase partitioning bioreactor applied to produced water treatment

Produced waters are the largest waste associated with the production of oil and gas; they contain dissolved salts, oil (dissolved and scattered organic compounds), chemicals and additives involved in the oil well operations, suspended particles, sand and other compounds, making their treatment very complex. In this paper, we propose the use of a TPPB (two phase partitioning bioreactor) for the biological treatment of produced waters. We model the application of the TPPB on the stream after classical pre-treatment stages: the reactor behaviour is based on the controlled release of substrate by means of an organic solvent. This study aims at developing a mathematical model for a TPPB adopting oleic alcohol (Adol 85 NF) as a solvent: we test model reliability by means of a sensitivity analysis in order to evaluate the reactor efficiency for chemical oxygen demand (COD) removal in a produced water stream, aimed at water reuse

BIODEGRADATION OF ACRYLIC PAINTS: PROCESS MODELLING OF BIOCIDE EFFECT ON BIOMASS GROWTH AT DIFFERENT TEMPERATURES

Abstract Acrylic paint, notwithstanding the attention paid during the production process, couldbe contaminated by bacteria. This is a consequence of microbiological residuals on the can, resulting in the alterationof paint characteristics. It is therefore necessary to provide an in-canpreservation of the paint by using a biocide.In this paper, the evolution of an in-can system, using a thermo-fluid dynamic model is presented; as a biocide, 2-methyl-4-isothiazolin-3-one, commercially known as MIT,was considered. The model was implemented on gPROMSsoftware and it was possible to determine the inhibitory concentration of the biocideinorder to guarantee both the protection of the can and the protection of thecover phase. To develop the model, kinetic parameters have been found by fitting available literature experimental data. As far as the thermodynamical parameters, theequilibrium between liquid and vapor phases was described bythe NRTLmodel (ASPEN Plus). The model has been validated through a comparison with experimental literature results using MIT alone and a mixture of biocides (MIT/BIT). The main results are that,at the maximum allowable concentration (100 ppm as imposed by law), the MIT biocide is able to protectthe paint for long periods, even when the temperature varies cyclically from 10 to 40°C

Polyphenols Extraction from Hazelnut Skin Using Water as Solvent: Equilibrium Studies and Quantification of the Total Extractable Polyphenols

In this work, a system for the extraction of antioxidant agents from waste vegetal matrices was studied. To this end, the extraction of polyphenols from food waste hazelnut skins was taken into consideration as a case study and a continuous set-up using distilled water at 70 °C as a solvent has been developed. Various extraction cycles were performed at different solid/liquid ratios (ranging from 2 to 5.7 g/l) in order to study the effect of this parameter on extraction efficiency. Through a mass balance, data obtained from the various cycles were used to calculate the total extractable polyphenols, and a value of 0.114 g of polyphenols per g of hazelnut skin was evaluated. Moreover, for two selected cycles the polyphenols concentration in the aqueous solution was measured at different time intervals in order to determine the extraction time, and in both tests it reached a plateau within the first hour. Finally, equilibrium concentrations of polyphenols in liquid and solid phases of the six tests were correlated by a linear isotherm equation, and a partition coefficient of 0.0368 l/g was evaluated through a fitting of experimental data

Comparison of three copromicroscopic methods to assess albendazole efficacy against soil-transmitted helminth infections in school-aged children on Pemba Island

Background The diagnostic accuracy of three faecal egg count techniques (Kato-Katz, McMaster and FLOTAC) to assess albendazole efficacy against soil-transmitted helminth (STH) infections was compared. Methods The study is registered with Current Controlled Trials [identifier: ISRCTN90088840]. During September-November 2009, 304 school-aged children on Pemba Island, Tanzania, were screened and those infected with Ascaris lumbricoides, hookworm or Trichuris trichiura were treated with a single dose of albendazole (400 mg). Twenty-one days post-treatment, children provided a single stool sample which was examined using the same diagnostic methods. All stool samples were divided into two aliquots and one was fixed in 5% formalin and examined using FLOTAC and McMaster approximately 6 months after collection. Results Using fresh stool samples, comparable prevalences were demonstrated for the three methods at baseline (90-92.2% for T. trichiura, 41.1-52.8% for hookworm, 32.9-37.2% for A. lumbricoides); FLOTAC was the most sensitive method at baseline and follow-up. Albendazole showed high cure rate (CR) against A.lumbricoides (90-97%), moderate CR against hookworm (63-72%) and very low CR against T.trichiura (6-9%), regardless of the technique used. Egg counts (eggs per gram) at baseline were similar for A. lumbricoides and for hookworm among the three methods, and higher using McMaster and Kato-Katz compared with FLOTAC for T. trichiura. All methods were similar for hookworm and A. lumbricoides egg reduction rate (ERR) estimation, but Kato-Katz indicated a significantly higher ERR than McMaster and FLOTAC for T. trichiura. Preserved stool samples revealed consistently lower FECs at baseline and follow-up for all STHs. Conclusion Further development and validation of standard protocols for anthelminthic drug efficacy evaluation must be pursue

How do cardiologists select patients for dual antiplatelet therapy continuation beyond 1 year after a myocardial infarction? Insights from the EYESHOT Post-MI Study

Background: Current guidelines suggest to consider dual antiplatelet therapy (DAPT) continuation for longer than 12 months in selected patients with myocardial infarction (MI). Hypothesis: We sought to assess the criteria used by cardiologists in daily practice to select patients with a history of MI eligible for DAPT continuation beyond 1 year. Methods: We analyzed data from the EYESHOT Post-MI, a prospective, observational, nationwide study aimed to evaluate the management of patients presenting to cardiologists 1 to 3 years from the last MI event. Results: Out of the 1633 post-MI patients enrolled in the study between March and December 2017, 557 (34.1%) were on DAPT at the time of enrolment, and 450 (27.6%) were prescribed DAPT after cardiologist assessment. At multivariate analyses, a percutaneous coronary intervention (PCI) with multiple stents and the presence of peripheral artery disease (PAD) resulted as independent predictors of DAPT continuation, while atrial fibrillation was the only independent predictor of DAPT interruption for patients both at the second and the third year from MI at enrolment and the time of discharge/end of the visit. Conclusions: Risk scores recommended by current guidelines for guiding decisions on DAPT duration are underused and misused in clinical practice. A PCI with multiple stents and a history of PAD resulted as the clinical variables more frequently associated with DAPT continuation beyond 1 year from the index MI

Bioplastics and Petroleum-based Plastics: Strengths and Weaknesses

the eutrophication; the abioticdepletion; and many others directly related tothe production, utilization, and disposal of the considered plastics. The aim of thiswork is to present a comparison between bioplastics and conventional plastics throughthe use of the “Life Cycle Assessment” methodology. In particular, the life cycleassessment’s Cradle to Grave of shoppers made from Mater-Bi (starch-based plastic)an polyethylene were reported and compared as a case study in order to highlightthe strengths and weaknesses of the bioplastics and the conventional plastics.; the acidification; the human toxicity; The application of biomass, such as starch, cellulose, wood, and sugar,used to substitute fossil resources for the production of plastics, is a widely acceptedstrategy towards sustainable development. In fact, this way a significant reductionof non renewable energy consumption and carbon dioxide emission is accomplished.In recent years, several typologies of bioplastics were introduced and the most importantare those based on cellulosic esters, starch derivatives, polyhydroxybutyrate,polylactic acid, and polycaprolactone. Nowadays, the most important tool to evaluatethe environmental impact of a (bio)plastic is the life cycle assessment that determinesthe overall impact of a plastic on the environment by defining and analyzing severalimpact categories index like the global warmin

Temperature and solvent effects on polyphenol extraction process from chestnut tree wood

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule. Polyphenols are generally divided into hydrolysable tannins (gallic acid esters of glucose and other sugars) and phenylpropanoids, such as lignins, flavonoids, and condensed tannins.They are widely found in natural products, nowadays they are extensively used in food and beverage industry and in pharmaceutical and nutraceutical industry for their positive effects on human health.In conventional processes polyphenols are extracted from vegetable material using water as solvent in a temperature range from 40 to 90. °C.The aim of this work is to characterize chestnut tree wood in terms of total extractable polyphenols and assess the temperature and solvent type effects on the polyphenol extraction process. To this end, experimental data on equilibrium distribution of polyphenols between solid and liquid phases for different temperatures (ranging from 60 to 80. °C) and different solvent solutions (water and ethanol-water solutions) are reported. The obtained results have been correlated by means of Freundlich isotherm.Experimental data are also reported about the batch extraction kinetics of polyphenols from solid phase and analysed by a mathematical model to estimate the polyphenol diffusion coefficient inside the chestnut wood particles and the mass transfer coefficient in the liquid phase. © 2010 The Institution of Chemical Engineers

Life Cycle Assessment of Polylactic Acid and Polyethylene Terephthalate Bottles for Drinking Water

The biodegradable plastics were introduced in the 1980s to detect possible renewable feedstock to produce nonpetroleum-based plastics as well as to reduce the environmental problems due to the increase of landfill volume. Furthermore, the biodegradable plastics have been used to reduce the environmental impact (in terms of energy requirement from nonrenewable resources and CO(2) gas emissions) derived from production, utilization, and disposal of petroleum-based plastics, like polyethylene terephthalate (PET). To this end, in the last years, different typologies of bioplastics were introduced (both biodegradable plastics and plastics made from renewable resources) like Mater-Bi (made from starch), poly-3-hydroxybuyrate, polycaprolactone, and polylactic acid (PLA). Nowadays, the most important tool to evaluate the environmental impact of a bioplastic and/or of a petroleum-based plastic (conventional plastic) is the life cycle assessment (LCA) that determines the overall impact of a plastic on the environment by defining and analyzing several impact indices directly related to production, utilization, and disposal of the considered plastics. In this work the LA (cradle to grave) of PLA bottles for drinking water was developed and compared to the LA of PET bottles for the same use. The obtained results highlighted that the true advantage of the PLA bottles with respect to the PET bottles arises from the use of renewable resources, but this benefit is paid in environmental terms due to the higher impact on human health and ecosystem quality (due to the use of pesticides, consumption of land, and consumption of water for the production of raw materials). (C) 2010 American Institute of Chemical Engineers Environ Prog, 30: 459-468, 201

PLLA Depolimerization Kinetics: A Preliminary Study

Poly(L-lactide) (PLLA) which is produced from renewable plant resources, is recently increasingly utilized as an alternative to petroleum-based polymers in order to reduce their impact on the environments. The monomer of PLLA is mainly produced from corn, which can also be utilized for food or to produce bioethanol or biofuels. Because of these reasons, the recycling of PLLA after its utilization, like other plastic material (PE, PP, or PET), must be carried out. For plastic material it is possible to carry out both a mechanical and chemical recycling: in the first case, the material is mechanically processed to obtain polymer pellets, while, in the second case, it is possible to obtain the monomer directly from the material depolymerization in order to reduce the consumption of renewable resources for the monomer synthesis. One of the most important processes used to produce lactic acid (LA) from PLLA is based on hydro-depolymerization of PLLA at high temperature and under pressure. In the present paper the hydrolytic depolymerization of pellets of PLLA in batch reactor at temperature near the melting temperature of the solid PLLA has been investigated and some preliminary experimental data are presented. Considering a residence time lesser than 120 minutes, a yield of lactic acid higher than 95% has been obtained at temperature equal to about 170-180 degrees C, at pressure equal to water vapour pressure and with a water/PLLA ratio equal to about 20