Bioregeneration of sulfate-laden anion exchange resin

Ion exchange technology removes ionic compounds from waters effectively but treatment of the spent regenerant is expensive. The bioregeneration of sulfate-laden strong base anion exchange resin was successfully tested using both pure and mixed sulfate-reducing bacterial cultures. The resin was first used for removal of sulfate from neutral (pH 6.7 ± 0.5) synthetic sodium sulfate solutions, after which the spent resin was regenerated by incubating with a viable sulfate-reducing bacterial culture in batch and column modes. In the batch bioregeneration tests, the achieved bioregeneration was 36-95% of the original capacity of the fresh resin (112 mg SO₄^2-/g) and it increased with regeneration time (1-14 days). The capacity achieved in the column tests during 24 hours of bioregeneration was 107 mg SO₄^2-/g after the first regeneration cycle. During the bioregeneration, sulfate was mainly reduced by the sulfate-reducing bacteria (approx. 60%), but part of it was only detached from the resins (approx. 30%). The resin-attached sulfate was most likely replaced with ions present in the liquid sulfate-reducing bacterial culture (e.g., HCO₃^-, HS^-, and Cl^-). During the subsequent exhaustion cycles with the bioregenerated resin, the pH of the treated sodium sulfate solution increased from the original 6.7 ± 0.5 to around 9. The study showed that biological sulfate reduction could be used for sulfate removal in combination with ion exchange, and that the exhausted ion exchange resins could be regenerated using a liquid sulfate-reducing bacterial culture without producing any brine.

Aqueous phase reforming of birch and pine hemicellulose hydrolysates

The current work focuses on studying the aqueous phase reforming (APR) of pine and birch hydrolysate obtained from waste wood by using organic acids available from biorefineries. Processing of representative synthetic mixtures was utilized in the work in order to support data interpretation related to the influence of different chemical compound and processing parameters on the APR of the actual hydrolysates. It was shown, that hydrogenation of the hydrolysates prior to APR was not feasible in the presence of formic acid, which ruled out one potential processing route. However, it was successfully demonstrated that birch and pine hydrolysates could be directly processed obtaining close to full conversion. The best results were obtained with tailored bimetallic Pd-Pt/sibunit catalyst in a trickle bed reactor system in the temperature range 175 °C-225 °C.

Vanadium removal by cationized sawdust produced through iodomethane quaternization of triethanolamine grafted raw material

In this study, two-step surface modification of sawdust using triethanolamine (at 180 °C) and iodomethane (at 42 °C) was performed to produce a novel quaternized biosorbent, TEA-I-SD. The characterization studies revealed significant morphological changes in the sawdust and successful quaternization with a nitrogen content of 5.75%. The highest vanadium removal (96.2%) was achieved at pH 4 (dosage 1 g/L, initial vanadium concentration 19.1 mg/L). Equilibrium was achieved within 8 h of contact time and the adsorption kinetics were well fitted with the pseudo-second-order model. Both film diffusion and intra-particle diffusion contributed to the adsorption process, while the latter was the rate-limiting step. The maximum vanadium adsorption capacity of TEA-I-SD (35.0 mg/g, pH 4) was close to the theoretical value obtained from the Langmuir model. The best fit was achieved with the Redlich-Peterson model, exhibiting a monolayer adsorption phenomenon. Tests with real mine water containing 11 mg/L of vanadium also confirmed its high removal (91.3%, dosage 1 g/L) using TEA-I-SD at pH 4. The TEA-I-SD could be reused three times without significant capacity loss after regeneration, although the desorption efficiency was rather low (synthetic solution: 38.5-40.5% and mine water: 26.2-43.1%).

Acid mine drainage treatment with novel high-capacity bio-based anion exchanger

Aminated peat (termed PG-Peat) produced using polyethylenimine and glycidyltrimethylammonium chloride was used for the removal of sulphate from real acid mine drainage (AMD) in batch and column mode sorption studies. In the batch tests, the highest sulphate removal capacity achieved was 125.7 mg/g. PG-Peat was efficient and rapid in sulphate removal from AMD even at low temperatures (2-5 °C), achieving equilibrium within a contact time of 30 min. The PG-Peat column treating real AMD showed even higher sulphate uptake capacity (154.2 mg SO₄^2-/g) than the batch sorption studies. The regenerative and practical applicability of PG-Peat was also tested in column set-ups using synthetic sulphate solutions (at pH 5.8 and pH 2.0). The sulphate uptake capacity obtained was higher in column mode when the solutions were treated at acidic pH (2.0) compared to pH 5.8. This could be attributed to the presence of cationized amine groups on PG-Peat under acidic pH conditions. Almost complete sulphate desorption was achieved with NaCl in the column that treated synthetic sulphate solution at pH 5.8, while the lowest desorption rates were observed in the column that treated acidic synthetic sulphate solution (pH 2).

Development of a process for microbial sulfate reduction in cold mining waters - Cold acclimation of bacterial consortia from an Arctic mining district

Biological sulfate removal is challenging in cold climates due to the slower metabolism of mesophilic bacteria; however, cold conditions also offer the possibility to isolate bacteria that have adapted to low temperatures. The present research focused on the cold acclimation and characterization of sulfate-reducing bacterial (SRB) consortia enriched from an Arctic sediment sample from northern Finland. Based on 16S rDNA analysis, the most common sulfate-reducing bacterium in all enriched consortia was Desulfobulbus, which belongs to the δ-Proteobacteria. The majority of the cultivated consortia were able to reduce sulfate at temperatures as low as 6 °C with succinic acid as a carbon source. The sulfate reduction rates at 6 °C varied from 13 to 42 mg/L/d. The cultivation medium used in this research was a Postgate medium supplemented with lactate, ethanol or succinic acid. The obtained consortia were able to grow with lactate and succinic acid but surprisingly not with ethanol. Enriched SRB consortia are useful for the biological treatment of sulfate-containing industrial wastewaters in cold conditions.

Production of aminated peat from branched polyethylenimine and glycidyltrimethylammonium chloride for sulphate removal from mining water

A novel bio-based anion exchanger was developed to remove sulphate from synthetic solutions and mine water. Different modification parameters such as chemical dosage and reaction time were tested when using a unique combination of branched polyethylenimine (PEI) and glycidyltrimethylammonium chloride (GTMAC) to produce an aminated biosorbent (termed PG-Peat). The novel and environment-friendly modification method was shown by FTIR and XPS analyses to be able to introduce quaternary ammonium and N-H groups into PG-Peat. The optimal modification conditions (PEI: 0.26 mmol/g, GTMAC: 0.0447 mol/g, reaction time: 18 h) resulted in the maximum sulphate uptake capacity (189.5 ± 2.7 mg/g) with a partition coefficient value of 0.02 mg/g/μM under acidic conditions. At low pH, amine groups on the peat surface became cationized, thereby resulting in a higher sulphate removal capacity. Batch sorption tests using PG-Peat exhibited rapid sulphate sorption after only five minutes of contact. The sulphate uptake by PG-Peat was unaffected by the presence of varying chloride concentrations, while slightly lower uptake capacity was observed when different concentrations of nitrate were present. The biosorbent showed high recyclability, which was revealed in regeneration studies. Tests were performed involving real mine water, where PG-Peat showed its potential to be a highly efficient biosorbent for sulphate removal at low pH values, indicating its suitability for treating acidic mine waters.

Synthesis of zerovalent iron from water treatment residue as a conjugate with kaolin and its application for vanadium removal

This study was aimed at examining the possible utilization of iron-rich groundwater treatment sludge in the synthesis of zerovalent iron (ZVI) as a conjugate with kaolin clay (Slu-KZVI), and its application for vanadium adsorption from aqueous solutions. Iron was extracted from the sludge using 1 M HCl and was used in ZVI synthesis by the sodium borohydride reduction method. The characteristics and performance of Slu-KZVI were compared to a kaolin modified with synthetic iron (FeCl₃·6H₂O) (Syn-KZVI). Adsorption results showed a competitive performance by both classes of KZVI, with Syn-KZVI slightly outperforming Slu-KZVI. X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy confirmed the formation of Fe⁰ on the core-shell structure of both modified adsorbents. In addition, the surface analysis of Slu-KZVI indicated the presence of P and Ca to a small extent, originating from the sludge. Both classes of sorbents performed better in solutions with acidic and neutral pH values (3-7). Surface complexation was thought to be the primary mechanism whereas simultaneous V(V) reduction and Fe oxidation (redox) reactions may also have taken place to some extent. A sorption test with groundwater confirmed that adsorbents were able to reduce vanadium to a very low concentration.

Iron-loaded Sphagnum moss extract residue for phosphate removal

Sphagnum moss extract residue (SMER), obtained after pressurized hot water extraction, was modified with Fe(III) and investigated for phosphate sorption. Although moss extract contains value-added compounds, SMER is considered to be waste until suitable uses can be developed. The effect of modification conditions were investigated, i.e. different initial Fe(III) concentrations (0.024, 0.048 and 0.072 mol/L Fe³⁺) and modification pH values (5, 7 and 9). A modification pH of 5 and the highest initial Fe(III) concentration (0.072 mol/L Fe³⁺) resulted in the highest phosphate removal efficiency, and thus was selected for further study. The removal efficiency was found to decrease with increasing pH in the range of 3-9. Maximum removal efficiency (82%) for phosphate sorption was observed at pH 3 after 24 h contact time (dosage 2 g/L, initial concentration 15 mg P/L). With increased contact time, the phosphate removal efficiency improved and reached equilibrium within 48 h. The Elovich model was found to provide the best fit to the kinetic data. A capacity of 9-13 mg P/g was obtained with a 24-h contact time at pH 4. A good fit was achieved with the Redlich-Peterson equation. FTIR analysis confirmed that carboxylic acid groups were involved in the modification process. X-ray diffraction analyses showed that amorphous two-line ferrihydrite was precipitated onto SMER, which was supported by X-ray photoelectron spectroscopy analyses.

Removal of metals from industrial wastewater and urban runoff by mineral and bio-based sorbents

The study was performed to evaluate chemically modified biosorbents, hydrochloric acid treated peat (HCl-P) and citric acid treated sawdust (Citric acid-SD) for their metal removal capacity from dilute industrial wastewater and urban runoff and compare their efficiency with that of commercially available mineral sorbents (AQM PalPower M10 and AQM PalPower T5M5 magnetite). Batch and column experiments were conducted using real water samples to assess the sorbents' metal sorption capacity. AQM PalPower M10 (consisting mainly of magnesium, iron and silicon oxides) exhibited excellent Zn removal from both industrial wastewater and spiked runoff water samples even at low dosages (0.1 g/L and 0.05 g/L, respectively). The high degree of Zn removal was associated with the release of hydroxyl ions from the sorbent and subsequent precipitation of zinc hydroxide. The biosorbents removed Ni and Cr better than AQM PalPower M10 from industrial wastewater and performed well in removing Cr and Cu from spiked runoff water, although at higher dosages (0.3-0.75 g/L). The main mechanism of sorption by biosorbents was ion exchange. The sorbents required a short contact time to reach equilibrium (15-30 min) in both tested water samples. AQM PalPower T5M5 magnetite was the worst performing sorbent, leaching Zn into both industrial and runoff water and Ni into runoff water. Column tests revealed that both HCl-P and AQM PalPower M10 were able to remove metals, although some leaching was witnessed, especially As from AQM PalPower M10. The low hydraulic conductivity observed for HCl-P may restrict the possibilities of using such small particle size peat material in a filter-type passive system.

Enhancing peat metal sorption and settling characteristics

Peat is an excellent material for metal sorption since it naturally contains different kinds of functional groups that can sorb metal cations from water. The main objective of this work was to test low-cost treatment (acid and alkali) methods for natural peat, which would improve the settling properties of peat particles while maintaining its metal removal efficiency. Particularly, the poor settling properties of peat hinder its practical application. The study revealed that NaOH-treated peat (0.1M) had excellent settling properties and could be applied in wastewater applications having mixing and settling systems without a settling aid. The superior leaching of humic and fulvic acids in alkaline treatment caused a change in morphology, making it a harder and sticky material. Moreover, the NaOH-treated (0.1M) peat was proven to be the most efficient material for nickel removal followed by the HCl-treated (0.2M) peat, citric acid-treated (0.16M) peat and water-treated peat. A higher temperature and longer time slightly increased the Ni removal efficiency with NaOH-treated peat material. The settling of HCl-treated peat was studied further using polyacrylamide flocculants (cationic, neutral, anionic). Cationic flocculants performed best and the cationic charge density also had an effect on the flocculation performance of peat particles. This study provides further evidence that peat can be applied in the treatment of metal-containing wastewaters.

Properties of vanadium-loaded iron sorbent after alkali regeneration

The aim of this research was to investigate the regeneration and reuse of a commercial granular iron sorbent (mainly goethite) when used in vanadium removal. A regeneration rate of 3 M NaOH was the highest (85%) achieved, followed by 2 M NaOH (79%) and 1 M NaOH (68%). The breakthrough curves show that the regenerated material can be reused. The BET (Brunauer-Emmett-Teller) surface area increased by 35-38% and the total pore volume increased by 123-130% as a consequence of NaOH treatment. The results indicated that sodium hydroxide could be used for the regeneration of iron sorbent although the regeneration was incomplete. This may be explained by the fact that vanadium diffusion into pores is a significant sorption mechanism in addition to complex formation with surface functional groups. As a consequence, vanadium desorbability from pores is not as effective as the regeneration of surface sites. X-ray photoelectron spectroscopy analyses confirmed a very low vanadium content on the surface of the NaOH-treated iron sorbent.

Formic acid aided hot water extraction of hemicellulose from European silver birch (Betula pendula) sawdust

Hemicellulose has been extracted from birch (Betula pendula) sawdust by formic acid aided hot water extraction. The maximum amount of hemicellulose extracted was about 70mol% of the total hemicellulose content at 170°C, measured as the combined yield of xylose and furfural. Lower temperatures (130 and 140°C) favored hemicellulose hydrolysis rather than cellulose hydrolysis, even though the total hemicellulose yield was less than at 170°C. It was found that formic acid greatly increased the hydrolysis of hemicellulose to xylose and furfural at the experimental temperatures. The amount of lignin in the extract remained below the detection limit of the analysis (3g/L) in all cases. Formic acid aided hot water extraction is a promising technique for extracting hemicellulose from woody biomass, while leaving a solid residue with low hemicellulose content, which can be delignified to culminate in the three main isolated lignocellulosic fractions: cellulose, hemicellulose, and lignin.

Removal of vanadium from industrial wastewater using iron sorbents in batch and continuous flow pilot systems

This study investigated the removal of vanadium from real industrial wastewater by using six iron materials: commercial iron sorbent (CFH-12), commercial mineral sorbent (AQM), blast furnace sludge (BFS), steel converter sludge (SCS), ferrochrome slag (FeCr) and slag from a steel foundry (OKTO). Batch tests revealed that CFH-12 (ferric oxyhydroxide) removed vanadium most efficiently, which was explained by its high iron content and the amorphous form of the iron, and that the sorption followed the Langmuir isotherm. With a dosage of 10 g/l and an initial vanadium concentration of 58.2 mg/l, 91-94% removal rates for vanadium were achieved in the studied pH range (3-9). Other sorbents showed significantly lower efficiency than CFH-12, with the exception of BFS at acidic pH (93%). Based on the batch test results, CFH-12 was selected for a pilot study made on site. The pilot study demonstrated the feasibility of CFH-12 to remove vanadium at high temperature (80 °C) from concentrated industrial wastewater with fluctuating water quality (vanadium concentration varied from 51 to 83 mg/l, pH about 9 (at 25 °C)). Leaching of impurities (mainly S, Ca, Mg and K) into the effluent occurred during the first day, but subsequently good quality effluent was produced (e.g. <0.1 mg/l V). During the pilot study, the amorphous iron material of CFH-12 was crystallized into a hematite-like phase (Fe_1.67 H_0.99 O₃), and goethite (FeO(OH)) with a higher average pore diameter, probably due to the hot process conditions to which CFH-12 was exposed for over five days.

A discretized model for enzymatic hydrolysis of cellulose in a fed-batch process

In the enzymatic hydrolysis of cellulose, several phenomena have been proposed to cause a decrease in the reaction rate with increasing conversion. The importance of each phenomenon is difficult to distinguish from batch hydrolysis data. Thus, kinetic models for the enzymatic hydrolysis of cellulose often suffer from poor parameter identifiability. This work presents a model that is applicable to fed-batch hydrolysis by discretizing the substrate based on the feeding time. Different scenarios are tested to explain the observed decrease in reaction rate with increasing conversion, and comprehensive assessment of the parameter sensitivities is carried out. The proposed model performed well in the broad range of experimental conditions used in this study and when compared to literature data. Furthermore, the use of data from fed-batch experiments and discretization of the model substrate to populations was found to be very informative when assessing the importance of the rate-decreasing phenomena in the model.

Characteristics and settling behaviour of particles from blast furnace flue gas washing

A lot of particles from iron-making are removed with blast furnace off-gas and routed to the gas cleaning system. As water is used for cleaning the gas, the produced wash water contains a large amount of particles such as valuable Fe and C. However, the presence of zinc prevents recycling. In addition, the high amount of calcium results in uncontrolled scaling. Therefore, the properties of the wash water from scrubber and sludge, from the Finnish metal industry (SSAB Raahe), were evaluated in this study. Size fractionation of wash water revealed that Fe, Zn, Al, Mn, V, Cr and Cd appeared mainly in the larger fractions (>1.2 μm) and Na, Mg, Si, Ni, K, Cu and As appeared mainly in the smaller fractions (<1.2 μm) or in dissolved form. Calcium was found both in the larger fractions and dissolved (∼60 mg/L). Most of the particles in wash water were included in the 1.2-10 μm particle size and were settled effectively. However, a clear benefit was observed when using a chemical to enhance particle settling. In comparison to 2.5 h of settling without chemical, the turbidity was further decreased by about 94%, iron 85% and zinc 50%. Coagulation-flocculation experiments indicated that both low and high molecular weight cationic polymers could provide excellent purification results in terms of turbidity. Calcium should be removed by other methods. The particles in sludge were mostly in the 2-4 μm or 10-20 μm fractions. Further sludge settling resulted in high solids removal.

Quaternized pine sawdust in the treatment of mining wastewater

Mining wastewater was treated using quaternized pine sawdust (QPSD) anion exchanger. The wastewater contained heavy metals (e.g. Sb, As, Co, Cr, Ni, V, U), NO3(-), among others, and a high concentration of SO4(2-). A series of column cycles imitating a real treatment process was conducted (three sorption/desorption cycles, a maintenance cycle with HCl and two sorption/desorption cycles). The effects of contact time and temperature (5°C and 23°C) were studied to assess the applicability of QPSD in the treatment of cold mining effluents. At 5°C, 85% of nickel was removed but the sorption was slower than at 23°C (initial Ni concentration was about 39 µg/l). Nickel was also removed in column efficiently (85-100% reduction). Treatment with HCl during the maintenance cycles did not hinder nickel sorption. Nickel was desorbed with both NaCl and HCl. Contrary to expectations, nitrate was not sorbed. QPSD showed selectivity towards nickel. However, uptake of uranium and cobalt was detected in column. Neutron activation analysis was used to detect metals sorbed onto the QPSD, and uptake of several metals was confirmed.

SNP diversity within and among Brassica rapa accessions reveals no geographic differentiation

Genetic diversity was studied in a collection of 61 accessions of Brassica rapa, which were mostly oil-type turnip rapes but also included two oil-type subsp. dichotoma and five subsp. trilocularis accessions, as well as three leaf-type subspecies (subsp. japonica, pekinensis, and chinensis) and five turnip cultivars (subsp. rapa). Two-hundred and nine SNP markers, which had been discovered by amplicon resequencing, were used to genotype 893 plants from the B. rapa collection using Illumina BeadXpress. There was great variation in the diversity indices between accessions. With STRUCTURE analysis, the plant collection could be divided into three groups that seemed to correspond to morphotype and flowering habit but not to geography. According to AMOVA analysis, 65% of the variation was due to variation within accessions, 25% among accessions, and 10% among groups. A smaller subset of the plant collection, 12 accessions, was also studied with 5727 GBS-SNPs. Diversity indices obtained with GBS-SNPs correlated well with those obtained with Illumina BeadXpress SNPs. The developed SNP markers have already been used and will be used in future plant breeding programs as well as in mapping and diversity studies.

Preparation of cationized pine sawdust for nitrate removal: Optimization of reaction conditions

Anion exchange materials were prepared from pine sawdust (Pinus sylvestris, PSD) through cationizing treatment with N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHMAC) in the presence of NaOH. Response surface methodology (RSM) was used to find the optimal reaction conditions. Three factors were chosen: reaction temperature (26-94 °C), reaction time (0.32-3.7 h) and NaOH/CHMAC molar ratio (0.19-2.2). Product yield (%) was used as a response. A quadratic model was fitted to the experimental data. The optimal conditions were: a reaction temperature of 57 °C, a reaction time of 1.8 h and a NaOH/CHMAC molar ratio of 1.32. A maximum nitrogen content of 2.6% was obtained at 60 °C, 3.7 h and a molar ratio of 1.2. The molar ratio had the greatest impact on the response. Regression analysis revealed that over 95% of the variance can be explained by the model. A maximum nitrate sorption capacity of 15.3 ± 1.4 mg N/g was achieved. The effect of CHMAC dose was also studied (a NaOH/CHMAC molar ratio of 1.2): 0.064 mol/g PSD was found to be near the optimum. Nitrate-contaminated groundwater (27.5 mg/l NO3) was treated with CPSD. Doses of 3-6 g/l resulted in 59-71% nitrate reduction.

Acid-catalysed xylose dehydration into furfural in the presence of kraft lignin

In this study, the effects of kraft lignin (Indulin AT) on acid-catalysed xylose dehydration into furfural were studied in formic and sulphuric acids. The study was done using D-optimal design. Three variables in both acids were included in the design: time (20-80 min), temperature (160-180°C) and initial lignin concentration (0-20 g/l). The dependent variables were xylose conversion, furfural yield, furfural selectivity and pH change. The results showed that the xylose conversion and furfural yield decreased in sulphuric acid, while in formic acid the changes were minor. Additionally, it was showed that lignin has an acid-neutralising capacity, and the added lignin increased the pH of reactant solutions in both acids. The pH rise was considerably lower in formic acid than in sulphuric acid. However, the higher pH did not explain all the changes in conversion and yield, and thus lignin evidently inhibits the formation of furfural.

Removal of nitrate by modified pine sawdust: effects of temperature and co-existing anions

The effect of temperature, sulphate and phosphate, and the initial nitrate concentration on nitrate removal was studied with synthetic solutions. Chemically modified pine sawdust (Pinus sylvestris) anion exchange resin (MPSD) was used in the sorption studies. The resin was synthesized by reacting pine sawdust with epichlorohydrin, ethylenediamine and triethylamine in the presence of N,N-dimethylformamide. Nitrate removal was successful at 5-70 °C. Higher temperatures caused nitrate removal to decrease moderately, but sorption capacities of 22.2-32.8 mg/g for NO3-N were achieved. The removal of nitrate in the presence of sulphate or phosphate was studied at concentrations of 30 mg N/l, 10-500 mg S/l and 1-50 mg P/l. A significant decrease in nitrate reduction was observed at sulphate and phosphate concentrations of 100 mg S/l and 50 mg P/l, respectively. The effect of initial nitrate concentration was studied in column. Nitrate sorption was clearly dependent on the initial concentration. Desorption of nitrate in column was completed using about 80 bed volumes of 0.1 M NaCl solution. The sorption data were fitted to the Langmuir, Freundlich and Redlich-Peterson adsorption models. The Redlich-Peterson and Langmuir models gave the best fit, which suggests monolayer sorption. Thermodynamic studies revealed that the sorption of nitrate was spontaneous and exothermic in nature. The results imply that modified pine sawdust could be a feasible alternative in the treatment of real industrial wastewaters.

Vanadium(V) removal from aqueous solution and real wastewater using quaternized pine sawdust

Cross-linked and quaternized pine sawdust was tested for vanadium removal from a synthetic aqueous solution as well as from real industrial wastewater which had a considerable amount of vanadium and other ions such as sulphate, ammonium and nickel. The maximum vanadium sorption capacity of the modified pine sawdust was found to be 130 mg/g in synthetic solution and 103 mg/g in real wastewater. Modified pine sawdust worked well over a wide range of pH. Column studies with real wastewater proved that vanadium was efficiently desorbed from the material with 2 M NaOH and that the material could be reused.

Kinetics of furfural destruction in a formic acid medium

Kinetics of furfural degradation in a formic acid catalyst was studied, and it was found out that the overall order of the reaction changes with the amount of acid catalyst.

Performance of a commercial industrial-scale UF-based process for treatment of oily wastewaters

An evaluation was made of the performance of a commercial industrial-scale ultrafiltration (UF)-based process for treatment of highly concentrated oily wastewaters. Wastewater samples were gathered from two plants treating industrial wastewaters in 2008, and in 2011 (only from one of the plants), from three points of a UF-based treatment train. The wastewater samples were analyzed by measuring the BOD7, COD, TOC and total surface charge (TSC). The inorganic content and zeta potentials of the samples were analyzed and GC-FID/MS analyses were performed. The removal performances of BOD7, COD, TOC and TSC in 2008 and 2011 for both plants were very high. Initial concentrations of contaminants in 2011 were lower than in 2008, therefore the COD and TSC reductions were also lower in 2011 than three years before. Regardless of the high performance of UF-based processes in both plants, at times the residual concentrations were considerable. This could be explained by the high initial concentrations and also by the presence of the dissolved compounds that were characterized. Linear correlation was observed between COD and TOC, and between COD and TSC. The correlation between COD and TSC could be utilized for process control purposes.

Hydrolysis of organosolv wheat pulp in formic acid at high temperature for glucose production

Organosolv methods can be used to delignify lignocellulosic crop residues for pulp production or to pretreat them prior to enzymatic hydrolysis for bioethanol production. In this study, organic solvent was used as an acidic hydrolysis catalyst to produce glucose. Hydrolysis experiments were carried out in 5-20% formic acid at 180-220 °C. Wheat straw pulp delignified with a formicodeli™ method was used as a raw material. It was found that glucose yields from pulp are significantly higher than yields from microcrystalline cellulose, a model component for cellulose hydrolysis. The results indicate that cellulose hydrolysis of real fibers takes place more selectively to glucose than hydrolysis of microcrystalline cellulose particles does. The effect of the particle size on pulp hydrolysis was investigated, the crystallinity of hydrolyzed pulp was measured by XRD analysis, and the product distribution and its influence on the process was discussed.

The gaf fimbrial gene cluster of Escherichia coli expresses a full-size and a truncated soluble adhesin protein

The GafD lectin of the G (F17) fimbriae of diarrhea-associated Escherichia coli was overexpressed and purified from the periplasm of E. coli by affinity chromatography on GlcNAc-agarose. The predicted mature GafD peptide comprises 321 amino acids, but the predominant form of GafD recovered from the periplasm was 19,092 Da in size and corresponded to the 178 N-terminal amino acid residues, as judged by mass spectrometry and amino acid sequencing, and was named DeltaGafD. Expression of gafD from the cloned gaf gene cluster in DegP-, Lon-, and OmpT-deficient recombinant strains did not significantly decrease the formation of DeltaGafD. The peptide was also detected in the periplasm of the wild-type E. coli strain from which the gaf gene cluster originally was cloned. We expressed gafD fragments encoding C-terminally truncated peptides. Peptides GafD1-252, GafD1-224, GafD1-189, and the GafD1-178, isolated from the periplasm by affinity chromatography, had apparent sizes closely similar to that of DeltaGafD. Only trace amounts of truncated forms with expected molecular sizes were detected in spheroplasts. In contrast, the shorter GafD1-157 peptide was detected in spheroplasts but not in the periplasm, indicating that it was poorly translocated or was degraded by periplasmic proteases. Pulse-chase assays using gafD indicated that DeltaGafD was processed from GafD and is not a primary translation product. The DeltaGafD peptide was soluble by biochemical criteria and exhibited specific binding to GlcNAc-agarose. Inhibition assays with mono- and oligosaccharides gave a similar inhibition pattern in the hemagglutination by the G-fimbria-expressing recombinant E. coli strain and in the binding of [(14)C]DeltaGafD to GlcNAc-agarose. DeltaGafD bound specifically to laminin, a previously described tissue target for the G fimbria. Our results show that a soluble, protease-resistant subdomain of GafD exhibits receptor-binding specificity similar to that for intact G fimbriae and that it is formed when gafD is expressed alone or from the gaf gene cluster.

Construction of a multihybrid display system: flagellar filaments carrying two foreign adhesive peptides

A multivalent, bifunctional flagellum carrying two different adhesive peptides in separate flagellin subunits within a filament was constructed in Escherichia coli. The inserted peptides were the fibronectin-binding 115-mer D repeat region of Staphylococcus aureus and the 302-mer collagen-binding region of YadA of Yersinia enterocolitica. Western blotting, immunoelectron microscopy, and adhesion tests with hybrid flagella from an in trans-complemented DeltafliC E. coli strain showed that individual filaments consisted of both recombinant flagellins.

Genome evolution of wild barley (Hordeum spontaneum) by BARE-1 retrotransposon dynamics in response to sharp microclimatic divergence

The replicative spread of retrotransposons in the genome creates new insertional polymorphisms, increasing retrotransposon numbers and potentially both their share of the genome and genome size. The BARE-1 retrotransposon constitutes a major, dispersed, active component of Hordeum genomes, and BARE-1 number is positively correlated with genome size. We have examined genome size and BARE-1 insertion patterns and number in wild barley, Hordeum spontaneum, in Evolution Canyon, Lower Nahal Oren, Mount Carmel, Israel, along a transect presenting sharply differing microclimates. BARE-1 has been sufficiently active for its insertional pattern to resolve individuals in a way consonant with their ecogeographical distribution in the canyon and to distinguish them from provenances outside the canyon. On both slopes, but especially on the drier south-facing slope, a simultaneous increase in the BARE-1 copy number and a decrease in the relative number lost through recombination, as measured by the abundance of solo long terminal repeats, appear to have driven the BARE-1 share of the genome upward with the height and dryness of the slope. The lower recombinational loss would favor maintenance of more full-length copies, enhancing the ability of the BARE-1 family to contribute to genome size growth. These local data are consistent with regional trends for BARE-1 in H. spontaneum across Israel and therefore may reflect adaptive selection for increasing genome size through retrotransposon activity.