pinecone/core-2020-05-10-deduplication huggingface dataset:
Study of saline wastewater influence on activated sludge flocs through automated image analysis

BACKGROUND: In activated sludge systems, sludge settling ability is considered a critical step in effluent quality and determinant of solid-liquid separation processes. However, few studies have reported the influence of saline wastewater on activated sludge. This work aims the evaluation of settling ability properties of microbial aggregates in a sequencing batch reactor treating saline wastewaters of up to 60 g L-1 NaCl, by image analysis procedures.
RESULTS: It was found that the sludge volume index (SVI) decreased with salt content up to 20 g L-1, remaining somewhat stable above this value. Furthermore, it was found that between the first salt concentration (5 g L-1) and 20 g L-1 aggregates suffered a strong deflocculation phenomenon, leading to a heavy loss of aggregated biomass. Regarding SVI prediction ability, a good correlation coefficient of 0.991 between observed and predicted SVI values was attained.
CONCLUSION: From this work the deflocculation of aggregated biomass with salt addition due to pinpoint floc formation, dispersed bacteria growth and protozoa absence could be established. With respect to SVI estimation, and despite the good correlation obtained, caution is advisable given the low number of SVI data points.Fundação para a Ciência e a Tecnologia (FCT)ALFA cooperation project BIEURAM
III (European Commission)CNPq (Brazil
Experimental and neural model analysis of styrene removal from polluted air in a biofilter

BACKGROUND: Biofilters are efficient systems for treating malodorous emissions. The mechanism involved during pollutant transfer and subsequent biotransformation within a biofilm is a complex process. The use of artificial neural networks to model the performance of biofilters using easily measurable state variables appears to be an effective alternative to conventional phenomenological modelling.  RESULTS: An artificial neural network model was used to predict the extent of styrene removal in a perlite-biofilter inoculated with a mixed microbial culture. After a 43 day biofilter acclimation period, styrene removal experiments were carried out by subjecting the bioreactor to different flow rates (0.15–0.9 m3 h−1) and concentrations (0.5–17.2 g m−3), that correspond to inlet loading rates up to 1390 g m−3 h−1. During the different phases of continuous biofilter operation, greater than 92% styrene removal was achievable for loading rates up to 250 g m−3 h−1. A back propagation neural network algorithm was applied to model and predict the removal efficiency (%) of this process using inlet concentration (g m−3) and unit flow (h−1) as input variables. The data points were divided into training (115 × 3) and testing set (42 × 3). The most reliable condition for the network was selected by a trial and error approach and by estimating the determination coefficient (R2) value (0.98) achieved during prediction of the testing set.  CONCLUSION: The results showed that a simple neural network based model with a topology of 2–4–1 was able to efficiently predict the styrene removal performance in the biofilter. Through sensitivity analysis, the most influential input parameter affecting styrene removal was ascertained to be the flow rate
Performance of an industrial biofilter from a composting plant in the removal of ammonia and VOCs after material replacement

BACKGROUND: Biofiltration is a suitable odor reduction technique for the treatment of gaseous emissions from composting processes, but little is known about the start-up of full-scale biofilters after material replacement and their performance after several years of operation. - RESULTS: Biofilter material (wood chips used previously as bulking agent in a composting process) can effectively remove ammonia and most of the volatile organic compounds (VOCs) content, achieving removal efficiencies greater than 70% for VOCs and near 90% for ammonia immediately after material replacement. These removal efficiencies were maintained for several months after material replacement. In the studied full-scale biofilter no lag phase was observed in the removal of ammonia whereas in the case of VOCs different patterns were detected during biofilter start-up. For the old biofilter material, after 4 years of operation, a statistically significant decrease of removal efficiency for ammonia in comparison with the new material was detected. No statistically significant differences were found in the case of VOCs. - CONCLUSIONS: Data on the emissions of several pollutants from biofilters treating composting exhaust gases have been systematically obtained. The tested filtering media presented adequate properties for biofiltration of gases emitted during the composting process
Bioprocesses for air pollution control

Bioprocesses have been developed as relatively recent alternatives to conventional, non-biological technologies, for waste gas treatment and air pollution control in general. This paper reviews major biodegradation processes relevant in this field as well as both accepted and major innovative bioreactor configurations studied or used nowadays for the treatment of polluted air, i.e. biofilters, one- and two-liquid phase biotrickling filters, bioscrubbers, membrane bioreactors, rotating biodiscs and biodrums, one- and two-liquid phase suspended growth bioreactors, as well as hybrid reactor configurations. Some of these bioreactors are being used at full-scale for solving air pollution problems, while others are still at the research and development stage at laboratory- or pilot-scale
Steady- and transient-state operation of a two-stage bioreactor for the treatment of a gaseous mixture of hydrogen sulphide, methanol and α-pinene

A two-stage bioreactor, comprising a biotrickling filter (BTF) as the first stage and a biofilter (BF) as the second stage, operated under steady- and transient-state conditions, was tested to remove gas-phase hydrogen sulphide, methanol and α-pinene.

RESULTS: Hydrogen sulphide and methanol were removed in the first stage, while α-pinene, was removed predominantly in the second-stage fungal BF. The effect of the liquid trickling rate was evaluated in the BTF, while concentration-dependent synergistic and antagonistic interactions in both reactors were assessed by varying the concentration of one pollutant, and by maintaining 100% removal of other pollutants. Increasing the liquid trickling rate decreased methanol removal significantly, from > 93% to 40%. Increasing the concentration of hydrogen sulphide from low to high loading rates did not affect the removal of volatile organic compounds (VOCs), however, the reverse occurred. Under all the conditions tested, α-pinene removal in the second-stage biofilter still remained higher than 80%.

CONCLUSIONS: The results show the maximum elimination capacities achievable for this complex ternary mixture, under a wide range of operating conditions
Oxidative processes of desulfurization of liquid

Environmental concerns have introduced a need to remove sulfur-containing compounds from light oil. As oxidative\ud
desulfurization is conducted under very mild reaction conditions, much attention has recently been devoted to this process.\ud
In this contribution, the developments in selective removal of organosulfur compounds present in liquid fuels via oxidative\ud
desulfurization, including both chemical oxidation and biodesulfurization, are reviewed. At the end of each section, a brief\ud
account of the research directions needed in this field is also included.Ministerio de Educación\ud
y Ciencia (España) proyecto ENE2007-07345-C03-01/ALTPeer reviewe
Treatment of concentrated solutions of natural humic acids by O3 (+ H2O2)

BACKGROUND:
Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O3 oxidation.
RESULTS:
At a specific O3 dose of 2.11 g O3 per g COD (17.0 g m-3 O3 (g) for 20 minutes), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 . 10-9 L s-1 m-2 Pa-1) than the permeability if the untreated solution is filtered (2.4 . 10-9 L s-1 m-2 Pa-1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H2O2 allows to obtain a better mineralization degree, i.e., UVA removal increased from 53% to 66% if H2O2 was added as from 10 minutes oxidation at the same molar flow rate as O3.
CONCLUSION:
O3 oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H2O2 can slightly improve its decomposition.status: publishe
Influence of hydrating agents on MgO hydration

BACKGROUND: The influence of different hydrating agents on the pH of the hydrating solutions, rate of hydration of MgO to Mg(OH)2 and product surface area was studied as a function of temperature of hydration. Hydrating agents used were aqueous solutions of ammonium chloride, magnesium acetate, magnesium nitrate, nitric acid, acetic acid, magnesium chloride, sodium acetate and hydrochloric acid and distilled water as control. RESULTS: There was not a significant difference in the hydration behavior of the hydrating agents up to 50 °C, where less than 10 % of magnesium hydroxide was formed. The amount of hydroxide increased at temperatures above 60 °C. When compared to the hydration in water, all the hydrating agents with the exception of sodium acetate showed a significant increase in the degree of hydration. Sodium acetate formed the lowest amount of magnesium hydroxide, ranging between 1.2 and 12.2 % magnesium hydroxide. The largest percentage (56.7 %) magnesium hydroxide was formed from the hydration in magnesium acetate. CONCLUSION: It seems that MgO hydration is a dissolution-precipitation process controlled by the dissolution of MgO. The increased degree of hydration in magnesium acetate is possibly due to the presence of acetate and Mg2+ ions.http://www.blackwell-synergy.com
Characterization of absorbent polymers for the removal of volatile hydrophobic pollutants from air

An emerging innovation for the treatment of polluted air consists in using a liquid–solid biphasic system, in which the sequestering phase contains inert polymer beads. The different polymers tested here for this purpose were; Hytrel® G3548L, Hytrel® G4078W, styrene butadiene copolymer, 28% and 31%, silicone rubber, PEBAX® 2533, and rubber tires. The selection of the most effective polymer(s) first requires a determination of the uptake of the pollutants by the solid phase in terms of key polymer properties such as partition coefficient, diffusion coefficient and biodegradability.  RESULTS: A significant difference was found in the uptake levels of α-pinene from the gas phase for the different polymers tested. Based on partition coefficient measurements, relatively non-polar polymers such as Kraton® tend to uptake α-pinene better than polar ones, such as Hytrel®. A reduction in the partition coefficient of α-pinene into polymers in the presence of water has also been observed. It was also proven that the tested polymers are not biodegradable.  CONCLUSIONS: The uptake of α-pinene by the different polymers tested was determined and it was shown that such polymers could be used for air pollution control. Furthermore, their non-biodegradability justifies their use as absorbents. This paper provides a new opportunity to work with biofilters (BFs)/biotrickling filters (BTFs) using polymers as a sequestering phase
Evaluation of a hydrothermal process for pretreatment of wheat straw : effect of particle size and process conditions

Hydrothermal processes are an eco-friendly processes that provide an interesting alternative for chemical utilization of lignocellulosic materials, in which water and crop residues are the only reagents. In this work the effect of process conditions (size distribution of the wheat straw, temperature and time) was evaluated against production of fermentable products.
RESULTS: The use of milled wheat straw fractions as a raw material containing blends of different particle size distribution showed that the latter had an influence on the final sugars in the hydrolysate. Improved values of glucose (21.1%) and xylose yields (49.32%) present in the hydrolysate were obtained with treatment severity factors of 2.77 and 3.36, respectively. Mathematical models were developed aimed at establishing the effect of process conditions on monosaccharide concentration and its degradation in the liquor.
CONCLUSION: This work shows that the use of wheat straw blends with various particle sizes has a significant effect on the extraction of fermentable products. The effect of treatment severity, which takes into account both processing time and temperature was also evaluated. These results are of importance for process design.ALBAN programm
Short-time estimation of biogas and methane potentials from municipal solid wastes

Biogas (GB) and methane (BMP) potentials are important parameters for the energy potential of the anaerobic digestion of municipal solid wastes (MSW) and to design full-scale facilities. However, no standard protocol has been defined for this measure. Several samples of mixed MSW and the source-selected organic fraction of municipal solid waste (OFMSW) obtained at different stages of their mechanical-biological treatment were analyzed. GB and BMP values obtained at different times were correlated. Biogas potentials calculated at 3, 4, 5, 6, 7, 14, 21, 50 and 100 days correlated well for the OFMSW samples. In the case of the MSW samples, only GB values obtained at times of 14 or more days correlated well with the ultimate biogas production (considered at 100 days). The biogas potential analyzed at 21 days (as proposed in some standard methods) accounted for 77% of the total biogas potential in OFMSW samples and for 71% in the MSW samples. These results are useful for the correct design and operation of anaerobic digestion plants in terms of retention time estimation and expected biogas and methane production
Aqueous two-phase micellar systems in an oscillatory flow micro-reactor: Study of perspectives and experimental performance

Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this batch or continuous micro-reactor has been presented as a new small-scale alternative for biological or physical-chemical applications.

RESULTS: ATPMS experiments were carried out in different OFM conditions (times, temperatures, oscillation frequencies and amplitudes) for the extraction of glucose-6-phosphate dehydrogenase (G6PD) in Triton X-114/buffer with Cibacron Blue as affinity ligand.

CONCLUSION: The results suggest the potential use of OFR, considering this process a promising and new alternative for the purification or pre-concentration of bioproducts. Despite the applied homogenization and extraction conditions have presented no improvements in the partitioning selectivity of the target enzyme, when at rest temperature they have influenced the partitioning behavior in Triton X-114 ATPMS.The authors acknowledge the financial support from FCT (Fundacao para a Ciencia e Tecnologia/Portugal, SFRH/BPD/26108/2005), as well as from FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo/Brasil), CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico/Brasil), and CAPES (Coordenacao para Aperfeicoamento do Ensino Superior/Brasil)
Fed-batch fermentation of olive mill wastewaters for lipase production

In the Mediterranean basin countries, huge amounts of olive mill wastewaters (OMW) are produced by the olive oil industry. It constitutes a serious environmental problem, nevertheless its composition turns OMW into a potential growth medium to lipolytic microorganisms. The aim of this work was to study lipase production as well as OMW degradation in fed-batch cultures of Candida cylindracea CBS 7869, Candida rugosa CBS 2275 and Yarrowia lipolytica W29 (ATCC 20460). Besides the improvement of lipase production, the fed-batch approach enhanced the effluent degradation, since it led to good COD and lipids reduction, both higher than 50%. C. rugosa achieved the highest value of lipase productivity (130 U L−1 h−1), in parallel with highest lipids reduction (77%). This study demonstrates thatOMWare becoming a competitive and valuable growth medium in fermentation processes with lipolytic microorganisms. The fed-batch strategy used proved to be an efficient approach to enhance lipase production from OMW and to reduce significantly the final organic load of the medium.The authors acknowledge the financial support provided by 'Fundacao para a Ciencia e Tecnologia' (Project PTDC/AMB/69379/2006; Grant SFRH/BD/27915/2006)
Heterogeneously catalyzing C-C coupling reactions with precious metal nanoparticles.

C–C coupling reactions are ubiquitous in synthetic chemistry, joining together fragments of larger molecules within overall synthetic schemes. Many obvious operational advantages would result from catalyzing such processes heterogeneously, however, there has been much controversy over whether metal nanoparticles (typically Pd) can be used in this role, or if catalysis in such cases occurs instead on metal ions leached into solution. In this mini-review selected examples of attempts to distinguish the homo- or hetero-geneity of such reactions, using Pd and Au nanoparticles, are highlighted. In particular, several interesting recent results are explored that demonstrate such metal nanoparticle catalyzed reactions can occur in a heterogeneous mode
Use of Desulfovibrio and Escherichia coli Pd-nanocatalysts in reduction of Cr(VI) and hydrogenolytic dehalogenation of polychlorinated biphenyls and used transformer oil

BACKGROUND 	Desulfovibrio spp. biofabricate  metallic nanoparticles (e.g. ‘Bio-Pd’) which catalyse the reduction of Cr(VI) to Cr(III) and dehalogenate polychlorinated biphenyls (PCBs).  Desulfovibrio spp. are anaerobic and produce H2S, a potent catalyst poison, whereas Escherichia coli can be pre-grown aerobically to high density, has well defined molecular tools, and also makes catalytically-active ‘Bio-Pd’. The first aim was to compare ‘Bio-Pd’ catalysts made by Desulfovibrio spp. and E. coli using suspended and immobilised catalysts. The second aim was to evaluate the potential for Bio-Pd-mediated dehalogenation of PCBs in used transformer oils, which preclude recovery and re-use.\ud
RESULTS 	Catalysis via Bio-PdD. desulfuricans and Bio-PdE. coli was compared at a mass loading of Pd:biomass of 1:3 via reduction of Cr(VI) in aqueous solution (immobilised catalyst) and hydrogenolytic  release of  Cl- from PCBs and used transformer oil  (catalyst suspensions). In both cases Bio-PdD. desulfuricans  outperformed  Bio-Pd E. coli  by ~3.5-fold,  attributable to a ~3.5-fold difference in their Pd-nanoparticle surface areas determined by magnetic measurements (Bio-PdD. desulfuricans) and by chemisorption analysis (Bio-PdE. coli).  Small Pd particles were confirmed on D. desulfuricans and fewer, larger ones on E. coli via electron microscopy. Bio-PdD. desulfuricans-mediated chloride release from used transformer oil  (5.6 \(\pm\) 0.8 \(\mu\)g mL-1 )  was comparable to that observed using several PCB reference materials. \ud
CONCLUSIONS 	At a loading of 1:3 Pd: biomass Bio-PdD. desulfuricans is 3.5-fold more active than Bio-PdE. coli, attributable to the relative catalyst surface areas reflected in the smaller nanoparticle sizes of the former.  This study also shows the potential of Bio-PdD. desulfuricans to remediate used transformer oil
Kinetic and thermodynamic investigation of Arthrospira (Spirulina) platensis fed-batch cultivation in a tubular photobioreactor using urea as nitrogen source

BACKGROUND: Fed-batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of two independent variables, temperature (T) and urea daily molar flow-rate (U), on cell growth, biomass composition and thermodynamic parameters involved in this photosynthetic cultivation. RESULTS: The optimal values obtained were T = 32 degrees C and U = 1.16 mmol L-1 d-1, under which the maximum cell concentration was 4186 +/- 39 mg L-1, cell productivity 541 +/- 5 mg L-1 d-1 and yield of biomass on nitrogen 14.3 +/- 0.1 mg mg-1. Applying an Arrhenius-type approach, the thermodynamic parameters of growth (?H* = 98.2 kJ mol-1; ?S* = - 0.020 kJ mol-1 K-1; ?G* = 104.1 kJ mol-1) and its thermal inactivation (Delta H-D(0) =168.9 kJ mol-1; Delta S-D(0) = 0.459 kJ mol-1 K-1; Delta G(D)(0) =31.98 kJ mol-1) were estimated. CONCLUSIONS: To maximize cell growth T and U were simultaneously optimized. Biomass lipid content was not influenced by the experimental conditions, while protein content was dependent on both independent variables. Using urea as nitrogen source prevented the inhibitory effect already observed with ammonium salts. Copyright (c) 2012 Society of Chemical IndustryCNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico), Sao Paulo-BrazilCNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico), Sao PauloBrazi
Nitrate removal from water by quaternized pine bark using choline based ionic liquid analogue

BACKGROUND: The objective of this study was to quaternize pine bark (PB) wood residues using green chemistry and to use the quaternized PB to remove nitrate (NO3−) from water. The quaternization process was achieved by reacting the wood residues with an ionic liquid analogue comprised of a choline chloride derivative and urea. Batch adsorption tests were used to delineate the NO3− uptake by the modified pine bark (MPB). Fourier Transform Infrared Spectroscopy (FTIR) analysis and Zeta potential measurements were used to characterize the changes at the surface of the PB due to quaternization and NO3− uptake.

RESULTS: The MPB has a maximum NO3− uptake capacity of 2.91 mmol g−1. The NO3− uptake kinetics indicated that diffusion through the boundary layer of the MPB was the rate limiting step. The Langmuir adsorption model provided a better fit for the uptake data than the Freundlich model, indicating monolayer adsorption. The uptake process was found dependent on concentration, pH and ionic strength, and was also spontaneous and exothermic. The desorption–regeneration experimental results indicated a 95% efficiency after five consecutive regeneration cycles.

CONCLUSIONS: The quaternization technique was found very effective for developing effective and green anion exchange resins to remove NO3− from water. © 2012 Society of Chemical IndustryPublishedN/