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The discovery and further development of biosorption phenomena provide a basis for a whole new technology aimed at the removal of various pollutants or the recovery of valuable resources from aqueous systems. Today, biosorption is one of the main components of environmental and bioresource technology. Since the status of scientific development of a technology can be reflected through analyses of the literatures pertaining to it, in this review, we qualitatively examine almost all aspects of biosorption research. A range of subjects are covered, including the initial history, raw materials, mechanisms, instrumental tools, process factors, modification and immobilization methods, recovery and regeneration, continuous processes, commercial application, and modeling studies of biosorption. Finally, we summarized the important considerations of the current research on biosorption, as well as the suggestions for its future directions. We believe that this review will prove to be useful for scientists and engineers in the performance of their research into biosorption.

Three different bacteria capable of degrading phenanthrene were isolated from sludge of a pulp wastewater treatment plant and identified as Acinetobacter baumannii , Klebsiella oxytoca , and Stenotrophomonas maltophilia . Phenanthrene degradation efficiencies by different combinations (consortia) of these bacteria were investigated and their population dynamics during phenanthrene degradation were monitored using capillary electrophoresis-based single-strand conformation polymorphism (CE-SSCP). When a single microorganism was used, phenanthrene degradation efficiency was very low (48.0, 11.0, and 9.0% for A. baumannii , K. oxytoca , and S. maltophilia respectively, after 360 h cultivation). All consortia that included S. maltophilia degraded ∼80.0% of phenanthrene and reduced lag time to 48 h compared to the 168 h of pure A. baumannii culture. CE-SSCP analysis showed that S. maltophilia was the predominant species during phenanthrene degradation in the mixed culture. The results indicate that mixed cultures of microorganisms may effectively degrade target chemicals, even if the microorganisms show low degradation activity in pure culture.

The adsorption of cadmium ions on granular activated carbon treated with nitric acid (NGAC), and untreated regular granulated activated carbon (RGAC) is reported in the absence and presence of mixtures of anionic (sodium dodecyl sulfate, SDS) and nonionic (Triton X-100, TX100) surfactants. In the absence of surfactants, NGAC adsorbed 8.7 times more Cd (0.165 mmol/g) than did RGAC (0.019 mmol/g). In RGAC suspensions, the amount of Cd sorbed increased significantly with increasing dose of SDS, to a maximum of 0.112 mmol/g. This increase was due to increased binding of Cd with sorbed SDS. However, in NGAC suspension, the amount of Cd sorbed was not increased further by the addition of SDS. It suggested that addition of SDS blocked the availability of surface functional groups in the microporous structure of NGAC.

Typical process measurements are usually correlated with each other and compounded with various phenomena occurring at different time and frequency domains. To take into account this multivariate and multi-scale nature of process dynamics, a multi-scale PLS (MSPLS) algorithm combining PLS and wavelet analysis is proposed. The MSPLS first decomposes the process measurements into separated multi-scale components using on-line wavelet transform, and then the resultant multi-scale data blocks are modeled in the framework of multi-block PLS algorithm which can describe the global relationships across the entire scale blocks as well as the localized features within each sub-block at detailed resolutions. To demonstrate the feasibility of the MSPLS method, its process monitoring abilities were tested not only for the simulated data sets containing several fault scenarios but also for a real industrial data set, and compared with the monitoring abilities of the standard PLS method on the quantitative basis. The results clearly showed that the MSPLS was superior to the standard PLS for all cases especially in that it could provide additional scale-level information about the fault characteristics as well as more sensitive fault detection ability.

A full-scale pre-denitrification process treating cokes wastewater containing toxic compounds such as phenols, cyanides and thiocyanate has shown good performance in carbon and nitrogen removal. However, field operators have been having trouble with its instability without being able to identify the causes. To clarify the main cause of these sudden failures of the process, comprehensive studies were conducted on the pre-denitrification process using a lab-scale reactor system with real cokes wastewater. First, the shock loading effects of three major pollutants were investigated individually. As the loading amount of phenol increased to 600 mg/L, more COD, TOC and phenol itself were flowed into the aerobic reactor, but phenol itself did not inhibit nitrification and denitrification, owing to the effect of dilution and its rapid biodegradation. Higher loading of ammonia or thiocyanate slightly enhanced the removal efficiency of organic matter, but caused the final discharge concentration of total nitrogen to be above its legal limit of 60 mg-N/L. Meanwhile, continuous inflow of abnormal wastewater collected during unstable operation of the full-scale pre-denitrification process, caused a sudden failure of nitrogen removal in the lab-scale process, like the removal pattern of the full-scale one. This was discovered to be due to the lack of inorganic carbon in the aerobic reactor where autotrophic nitrification occurs.

In this article, we propose an individual-based and stochastic modeling approach that is capable of describing the bacterial cell population dynamics during a batch culture. All stochastic nature inherent in intracellular molecular level reactions and cell division processes were considered in a single model framework by embedding a sub-model describing individual cell's growth kinetics in a discrete event simulation algorithm. The resultant unique feature of the model is that the effects of the stochasticities on the cell population dynamics can be investigated for different substrate-dependent cell growth kinetics. When Monod kinetics was used as the sub-model, the stochasticities only slightly affected the cell mass increase and substrate consumption profiles during the batch culture although they were still important in describing the changes of cell population distributions. When Andrews substrate inhibition kinetics was used, however, it was revealed that the overall cell population dynamics could be seriously influenced by the stochasticities. Under a critical initial substrate level, the cell population could proliferate against the substrate inhibition only when the stochasticities were considered.

Distributed wastewater treatment plants (WTPs) have been synthesized to reduce costs associated with wastewater treatment. This study developed a mathematical optimization model to synthesize existing distributed and terminal WTPs into an economical total wastewater treatment network system (TWTNS) from the perspective of life cycle cost (LCC). The objective function was formulated from the principal cost contributors in the construction, operations and maintenance, and disposal stages. The mass balances were formulated on the basis of the superstructure model, and the constraints were formulated to reflect real situations. A case study compared the LCC-minimized TWTNS (LNS) generated with this model to a conventional wastewater treatment system (CWTS) operated in a plant and to the TWTNS (FNS) generated by minimizing a total flowrate of wastewater treated in distributed WTPs. The LCC of the LNS was 12% less than that of the CWTS and was 27% less than that of the FNS, which validated the effectiveness of the model. This model can be used to practically retrofit existing WTPs.

Among various plant-based natural biomaterials, pine bark was chosen as an efficient biomaterial capable of removing toxic Cr(VI) from aqueous solution. XPS spectra indicated that Cr(VI) was abiotically reduced to Cr(III) in both liquid and solid phases. The Cr(VI)-reducing capacity of pine bark was determined as 545 (±1.3) mg-Cr(VI) g−1 of it, which was 8.7 times higher than that of a common chemical Cr(VI)-reductant, FeSO4·7H2O. Because pine bark could completely reduce toxic Cr(VI) to less toxic or nontoxic Cr(III) even at neutral pH, it was used as an organic reductant to remediate Cr(VI)-contaminated soil in this study. Soil slurry system using a bottle roller was applied to ex situ slurry-phase remediation experiments. In the soil slurry system, pine bark completely reduced Cr(VI) to Cr(III) and adsorbed the reduced-Cr(III) on its surface. Abiotic remediation rate of Cr(VI)-contaminated soil increased with the increase of pine bark dosage and with the decreases of Cr(VI) and water contents. In conclusion, pine bark can be used to remediate Cr(VI)-contaminated soil efficiently and environmentally friendly.

A lab-scale serial anoxic-aerobic reactor for the pre-denitrification process was continuously operated to efficiently and economically treat actual cokes wastewater containing various pollutants, such as phenol, ammonia, thiocyanate and cyanide compounds. The biodegradation efficiencies of the pollutants were examined by changing hydraulic retention time (HRT) as a main operating variable. The long-term operation of the pre-denitrification process reactor showed that approximately 100% phenol, approximately 100% free cyanide, approximately 100% SCN(-), 97% ammonia, 85% COD, 84% TOC (total organic carbon) and 83% TN (total nitrogen) were removed at HRT above 11.9h. Removal efficiency of total cyanides significantly decreased with a decrease in the HRT. Free cyanide and some of total cyanides were removed in anoxic reactor, whereas thiocyanate was removed in aerobic reactor. Phenol was completely removed under successive anoxic and aerobic conditions. Although actual cokes wastewater contained high concentrations of various toxic pollutants, the pre-denitrification process showed stable and successful performances in both nitrification and denitrification reactions.

The performances of various soil washing processes, including surfactant recovery by selective adsorption, were evaluated using a mathematical model for partitioning a target compound and surfactant in water/sorbent system. Phenanthrene was selected as a representative hazardous organic compound and Triton X-100 as a surfactant. Two activated carbons that differed in size (Darco 20-40 mesh and >100 mesh sizes) were used in adsorption experiments. The adsorption isotherms of the chemicals were used in model simulations for various washing scenarios. The optimal process conditions were suggested to minimize the dosage of activated carbon and surfactant and the number of washings. We estimated that the requirement of surfactant could be reduced to 33% of surfactant requirements (from 265 to 86.6g) with a reuse step using 9.1g activated carbon (>100 mesh) to achieve 90% removal of phenanthrene (initially 100mg kg-soil(-1)) with a water/soil ratio of 10.

Water network synthesis has been used to conserve water resources and reduce economic costs. In this study, all contributors to environmental burdens and economic costs of water network systems were estimated to analyze the effects of objective functions on their environmental and economic performances. A total freshwater flowrate-minimized water network system (FWNS) and a total freshwater cost-minimized water network system (CWNS) were independently synthesized. Life cycle assessment and life cycle costing were performed to evaluate and compare the environmental and economic performances of the two water network systems. The CWNS was more environmentally and economically friendly than the FWNS because the CWNS was synthesized by minimizing the consumption of deionized water, which has higher unit cost and unit environmental effect scores than industrial water. Also this study demonstrated that the consumption rates of freshwater and electricity, as well as their unit environmental effect scores, should be used as principal contributors and weighting factors for the formulation of an objective function to generate the most environmentally friendly water network system, while the costs of piping and freshwater, as well as their unit costs, should be included to generate the most economically friendly system.

The effects of pH on hydrogen fermentation of glucose by newly isolated H(2)-producing bacterium Clostridium tyrobutyricum JM1 were investigated in batch cultivations. The changes of carbon material and energy balances by pH conditions provided useful information for understanding and interpreting the regulatory system of the microorganism, and for optimization of a desired product, in this case, molecular hydrogen. The most probable metabolic pathways of C. tyrobutyricum JM1 were determined through an accurate analysis of stoichiometry and the consistency of the experimental data, checked by high carbon recovery. The carbon material and energy balances were adequately applied to estimate the carbon-flow distribution. They suggested that pH 6.3 was appropriate to maximize hydrogen production with a high concentration of butyrate and balanced activities of NADH.

A fermentative hydrogen-producing bacterium was isolated from a food waste treatment process. The biological hydrogen production rate by the pure isolate (designated as Clostridium tyrobutyricum JM1) was dependent on various nutritional and environmental conditions. In this study, to enhance hydrogen production rate, the individual and mutual effects of three key process variables such as glucose concentration, pH and temperature were investigated through response surface methodology (RSM) in a batch system. A Box–Behnken design was employed to determine the effect of the three independent variables on the hydrogen production rate and to find the optimum condition of each variable for improved hydrogen production. Experimental results showed that a maximum hydrogen production rate of 5089 ml H 2 (g dry cell h) −1 was obtained under the condition of glucose concentration of 102.08 mM, temperature 35 °C and pH 6.5, and all three factors had significant influences on the specific hydrogen production rate. The RSM with the Box–Behnken design was a useful tool for achieving the high rate of hydrogen production by C. tyrobutyricum JM1.

A real-time remote monitoring system for wastewater treatment plants (WWTPs) has been developed to give local operators a guideline that would allow them to arrive at the optimum operational strategy in the early stage of a process disturbance. Especially, small-scaled WWTPs in Korea's rural areas show a large fluctuation in their influent loading and, therefore, they require an efficient operation for treatment of organic matter, nitrogen and phosphorus. However, under requirements to lower running costs, most of the small-scaled WWTPs are being forced to operate with a minimum number of operators. It is too costly for them to employ a local expert to maintain plant systems properly. In recent years, recognition of these problems has raised great interests in real-time remote monitoring systems. They serve the key information needed for efficient operation, and help to transfer knowledge from the experts at a remote control center to local operators in real-time. In this study, both operation data and measurement values from a novel mobile multi-sensor system were transmitted on-line by a telecommunication system. Then multivariate statistical process controls and software sensor techniques were applied to supervise local WWTPs. The developed remote monitoring system makes it possible to monitor the current plants’ statuses and to support the operation of local wastewater systems.

A pre-denitrification process has been used to treat cokes wastewater containing toxic compounds such as phenols, cyanides and thiocyanate in Korea, and has showed very good removal efficiencies in carbon and nitrogen removals. However, a considerable amount of cyanides in the form of ferricyanide remained in the effluent of biological treatment process. Though ferrous iron is known to be more efficient in removing ferricyanide than ferric iron, ferric chloride solution has been used as a chemical precipitant due to its low cost for a long time. In this study, ferrous sulfate and ferric chloride solutions were used to remove cyanides remained in the effluent of the pre-denitrification process. The optimum dosage of each iron solution was evaluated in batch experiments with or without PAC solution. In addition, the amount of produced chemical sludge and the settling performance of it were also examined numerically. In conclusion, economic assessment indicated that ferrous iron is more economically profitable than ferric iron in spite of its high cost.

A fermentative hydrogen-producing bacterium, Clostridium tyrobutyricum JM1, was isolated from a food waste treating process using 16S rRNA gene sequencing and amplified ribosomal DNA restriction analysis (ARDRA). A fixed-bed bioreactor packed with polyurethane foam as support matrix for the growth of the isolate was operated at different hydraulic retention time (HRT) to evaluate its performance for hydrogen production. The reactor achieved the maximal hydrogen production rate of 7.2 l H2 l−1 d−1 at 2 h HRT, where hydrogen content in biogas was 50.0%, and substrate conversion efficiency was 97.4%. The maximum hydrogen yield was 223 ml (g-hexose)−1 with an influent glucose concentration of 5 g l−1. Therefore, the immobilized reactor using C. tyrobutyricum JM1 was an effective and stable system for continuous hydrogen production.

Distribution of a hazardous hydrophobic organic compound (HOC) and a nonionic surfactant in aqueous/activated carbon systems was investigated. Phenanthrene was selected as a representative HOC and Triton X-100 as a surfactant. Three activated carbons that differed in size (Darco 20–40, 12–20 and 4–12 mesh sizes) were used in the adsorption experiments. The system was analyzed using a mathematical partitioning model and compared with intrinsic sorption of phenanthrene without the effect of sorbed surfactant. Phenanthrene was sorbed onto activated carbon in a greater amount than an estimated value by intrinsic sorption, even though surfactant molecules covered most of surfaces. The sorbed surfactant was much more effective as a sorbent for phenanthrene, in the range of 1.2–98 for effectiveness factor, than was activated carbon, particularly at high surfactant doses. We introduced surface molar solubilization ratio (MSRs) for sorbed micelles of surfactant and mathematically estimated using effectiveness factor and available carbon fraction of activated carbon after surfactant sorption. The MSRs for sorbed surfactant was 5–46 times higher than the MSR for micellar surfactant in bulk solution. The sorbed surfactant onto activated carbon can more effectively remove hazardous organic compounds in liquid environmental samples.

A micro-electro-mechanical-systems (MEMS)-based IR spectrometer has been designed and fabricated. The proposed micro-spectrometer consists of multi-slit grating and bolometric IR detector array. The grating is used for dispersion of an incident optical radiation into different wavelength components. The grating structure is patterned by reactive ion etching (RIE) of aluminum deposited on dielectric membrane, which is fabricated over silicon wafer. The IR detector part adopts a resistive bolometer that changes its resistance due to the temperature increment. The presence of IR at the specific wavelength can be detected by noticing the resistance change when temperature increases due to an incident IR ray. Vanadium oxide is adopted for resistive bolometer of IR spectrometer in this work because of its higher temperature coefficient of resistance (TCR) which is needed for the better sensitivity. Two parts that composes the MEMS-based IR spectrometer, aluminum multi-slit grating and thermal-type vanadium oxide IR detector, are processed independently and bonded as a final step.

The synthesis of distributed wastewater treatment plants (WTPs) has been studied to reduce capital and operating costs associated with wastewater treatment. In this study, the environmental and economic feasibility of a total wastewater treatment network system (TWTNS) including distributed and terminal WTPs was estimated using life cycle assessment (LCA) and life cycle costing (LCC) methods. Wastewater sources and existing distributed and terminal WTPs in an iron and steel plant were networked. The TWTNS was generated from the optimal solution to a mathematical optimization model and compared to a conventional wastewater treatment system (CWTS). The environmental effect scores of the TWTNS were from 29.6% to 68.3% higher than those of the CWTS because of higher electricity consumption required to pump wastewater to the networked WTPs. However, the life cycle cost of the TWTNS was lower than that of the CWTS by 10.1% because of the decrease of the labor cost resulting from the closing of three distributed WTPs. Overall, the TWTNS was no more eco-efficient than the CWTS because the increase of environmental burdens outweighed the decrease of economic costs.

A vanadium pentoxide ()-based bolometric infrared (IR) sensor has been designed and fabricated using micro electro mechanical systems (MEMS) technology for glucose detection and its resistive characteristics has been illustrated. The proposed bolometric infrared sensor is composed of the vanadium pentoxide array that shows superior temperature coefficient of resistance (TCR) and standard silicon micromachining compatibility. In order to achieve the best performance, deposited thin film is optimized by adequate rapid thermal annealing (RTA) process. Annealed vanadium oxide thin film has demonstrated a linear characteristic and relatively high TCR value (). The resistance of vanadium oxide is changed by IR intensity based on glucose concentration.

Much effort has been made in reducing the carbon footprint to mitigate climate change. However, water network synthesis has been focused on reducing the consumption and cost of freshwater within each industrial plant. The objective of this study is to illustrate the necessity of the cooperation of industrial plants to reduce the total carbon footprint of their water supply systems. A mathematical optimization model to minimize global warming potentials is developed to synthesize (1) a cooperative water network system (WNS) integrated over two plants and (2) an individual WNS consisting of two WNSs separated for each plant. The cooperative WNS is compared to the individual WNS. The cooperation reduces their carbon footprint and is economically feasible and profitable. A strategy for implementing the cooperation is suggested for the fair distribution of costs and benefits. As a consequence, industrial plants should cooperate with their neighbor plants to further reduce the carbon footprint.

Iron making industry has generated a large amount of waste slag containing iron. Feasibility of utilizing the slag to remove toxic Cr(VI) from aqueous phase was investigated in a batch system. Main mechanism of Cr(VI) removal by the slag was its reduction into Cr(III) by the Fe(II) released from the slag under acidic condition. One gram of the slag could remove 56.1 (± 0.5) mg of Cr(VI) at pH 2. The removal rate of Cr(VI) increased with a decrease in pH or increase of slag dosage. A simple kinetic model in the form of −d[Cr(VI)]/d t = k [slag] n was developed to predict the time-dependent concentration of Cr(VI) in aqueous phase. At pH 2, the model successfully described the Cr(VI) removal behaviors in aqueous phase under various slag dosages and initial Cr(VI) concentrations.

A silicon sensor is very attractive material for medical imaging due to its intrinsic high resolution and fast readout. Silicon sensors of various types were fabricated on a 380 μm-thick n-type, float zone, 5 in. wafer which has high resistivity, orientation, and is double-sided polished. We manufactured not only DC- and AC-coupled strip sensors but also pixel sensors and RC chips. The RC chips were fabricated for the purpose of using signal readout of the DC-coupled strip sensors. Electrical characteristics of the fabricated silicon sensors, leakage current and capacitance as a function of reverse bias voltage, were measured. Coupling capacitors and biasing resistors in the AC-coupled strip sensors were made by separating implantation from metallization strips with a thin oxide layer and made of polysilicons, respectively. The capacitance and resistance of each channel in the AC-coupled sensor were measured and compared with target values. The signal-to-noise ratio of the fabricated large pixel sen...

To develop an optimal bioprocess for secondary metabolite production and explain the bioprocess at the molecular level, we examine the synergistic effects of sequential treatment with methyl jasmonate (MJ), salicylic acid (SA) and yeast extract (YE) on benzophenanthridine alkaloid accumulation and protein expression in Eschscholtzia californica suspension cultures. Serial treatment of MJ, SA and YE at 24h intervals enhanced the accumulation of dihydrosanguinarine (2.5 times) and sanguinarine (5.5 times). This sequential treatment using different signal elicitors was more effective than single elicitor or simultaneous treatment of the elicitors; it induced benzophenanthridine alkaloid accumulation to 917.7+/-42.0mg/L. Also, (S)-methylcoclaurine-3'-hydroxylase (CYP80B1) and 3'-hydroxy-(S)-N-methylcoclaurine-4'-O-methyltransferase (4'OMT) expressions among enzymes in sanguinarine biosynthetic pathway explained the synergistic effects by sequential treatment of the elicitors. The sequential treatment strategy using elicitors related to different signal transduction pathways can be used to design better processes to increase accumulation of secondary metabolites in plant cell culture. Analysis of protein expression provides the detailed information about metabolite accumulation through the correlated results.

The individual and mutual effects of glucose concentration, temperature and pH on the hydrogen production by Enterobacter aerogenes were investigated in a batch system. A Box–Behnken design and response surface methodology (RSM) were employed to determine the optimum condition for enhanced hydrogen production. The hydrogen production rate was investigated by simultaneously changing the three independent variables, which all had significant influences on the hydrogen production rate. The maximum hydrogen production rate of 425.8 ml H 2 (g dry cell h) −1 was obtained under the optimum condition of glucose concentration 118.06 mM, temperature 38 °C and pH 6.13. The experimental results showed that the RSM with the Box–Behnken design was a useful tool for achieving high rate of hydrogen production by E. aerogenes .

To enhance biological removal efficiency of total cyanides, bioaugmentation was applied to a full-scale cokes wastewaters treatment process. After a laboratorial-scale cultivation (up to 1.2 m3) of a cyanide-degrading yeast (Cryptococcus humicolus) and unidentified cyanide-degrading microorganisms, the microbial consortium was inoculated into a fluidized-bed type process (1280 m3), and then enriched for two months with a huge supply of glucose, KCN and other nutrients. Target wastewater was effluent of a biological pre-denitrification process for treating cokes wastewater, and contained about 14 mg/L of total cyanides in the form of ferric cyanide. This may be a first or rare report on the full-scale bioaugmentation of specialized-microorganisms. However, continuous operation of the full-scale cyanides-degrading bioprocess showed poor removal efficiency than expected owing to poor settling performance of microbial flocs, slow biodegradation rate of ferric cyanide and lack of organic carbon sources within the wastewater. Therefore, there is a need for further studies on how to solve these operating problems in full-scale bioaugmentation approach.

Recently, a new and simple kinetic model was derived from a basic concept of the redox reaction between Cr(VI) and biomaterials, and successfully described the removal behavior of Cr(VI) under various Cr(VI) and biomaterial concentrations. However, this model did not consider the effects of pH and temperature on the Cr(VI) removal by biomaterials. In this study, a new efficient biomaterial, pine needle, capable of removing Cr(VI) was used as a model one to study the Cr(VI) removal by biomaterials. Analysis of chromium species in aqueous and solid phases revealed that the removal mechanism of Cr(VI) by pine needle was its reduction into Cr(III). The removal rate of Cr(VI) increased with a decrease in pH or with an increase of temperature. Finally, an advanced kinetic model in the form of - d [ Cr ( VI ) ] / d t = A e E a / RT [ H + ] n [ Cr ( VI ) ] [ OCs ] was derived, and successfully predicted the time-dependent Cr(VI) concentration at various pHs (2–4) and temperatures (10–55 °C).

Water network synthesis contributes to cost reduction and the conservation of water resources by reducing water consumption. A mathematical optimization model is developed in this study to synthesize an environmentally friendly water network system (WNS) by minimizing environmental impacts of a WNS. The concept of life cycle assessment (LCA) is integrated into the objective function of the model to evaluate the environmental effect scores (EESs) of principal contributors to the environmental impacts of a WNS and to optimize tradeoffs among their EESs. The mass balances are formulated from the superstructure model, and the constraints are formulated to take into account the real situation in industrial plants. A case study demonstrates the effect of the objective function on the configuration and environmental performance of a WNS and validates the mathematical optimization model. This model can be used for the design for environment (DfE) of WNSs in the context of sustainable development.

The reduction of toxic Cr(VI) to the less or nontoxic Cr(III) may be an useful detoxification technique for the treatment of Cr(VI)-contaminated waters. Recently, the protonated biomass of brown seaweed, Ecklonia, was shown to completely reduce Cr(VI) to Cr(III) in the pH range 1-5. The reduction of Cr(VI) to Cr(III) appeared to occur at the surface of the biomass. In this study, abiotic Cr(VI) reduction by the biomass was performed with various contact times, pHs and initial Cr(VI) concentrations, and surface and bulk characteristics of the Cr-laden biomass was then investigated using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The XPS spectra indicated that the Cr(VI) bound to the biomass was completely reduced to Cr(III) at tested various conditions. XANES and EXAFS spectra of the Cr-laden biomass were very similar to those of Cr(III)-acetate, which means that the Cr bound to the biomass during Cr(VI) reduction had an octahedral geometrical arrangement. The bonding distance of the chromium oxygen atoms was approximately 1.97-1.99 A. In conclusion, it was obvious that oxygen containing groups, such as carboxyl and phenolic groups, play a major role in the binding of the Cr(III) resulting from the abiotic reduction of Cr(VI) by the biomass.

Water network synthesis has been used to conserve water resources and reduce freshwater costs. However, a mathematical optimization model to maximize the profitability of a water network system has not been developed. The objective of this work was to develop the model to synthesize an economically friendly water network system by maximizing its net present value (NPV). The mathematical optimization model includes principal contributors to incremental costs and benefits resulting from water network synthesis. Tradeoffs between the incremental costs and benefits derived from water reuse are optimized to maximize the NPV. In a case study, an NPV-maximized water network system was more profitable than the total freshwater flow-rate-minimized and total freshwater cost-minimized water network systems. The model can be used to practically implement water network systems and can be applied to other process integration technologies to generate economically friendly heat and hydrogen network systems.

A simple and efficient protocol was developed for culturing Cu-tolerant and Cu-accumulating plants via pre-adaptation to Cu during plant tissue culture. We induced multiple shoots from begonia (Begonia evansiana Andr.) leaf explants on MS medium supplemented with naphtaieneacetic acid and benzyladenine. After 3 months, small plantlets were transferred to MS medium supplemented with for pre-adaptation to Cu and cultured for 5 months. Then, these plantlets were individually planted in pots containing artificial soil. An additional 500 mg of Cu dissolved in 1/4 strength MS solution was applied to each pot during irrigation over the course of 2 months. We planted pre-adapted and control begonias in soil from the II-Kwang Mine, an abandoned Cu mine in Pusan, Korea, to examine their ability to tolerate and accumulate Cu for phytore-mediation. Pre-adapted begonias accumulated Cu/g dry root tissue over the course of 45 days. On the other hand, non-Cu-adapted controls accumulated only Cu/g dry root tissue. To enhance Cu extraction, chelating agents, ethylenediamine tetraacetic acid (EDTA)-dipotassiun and pyridine-2,6-dicarboxylic acid (PDA), were applied. While the chelating agents did not enhance accumulation of Cu in the roots of control begonias, EDTA application increased the level of Cu in the roots of pre-adapted begonias twofold (to Cu/g dry root tissue). Because pre-adapted begonias accumulated a large amount of Cu, mainly in their roots, they could be used for phytostabilization of Cu-contaminated soils. In addition, as a flowering plant, begonias can be used to create aesthetically pleasing remediation sites.

Failure in nitrogen removal of cokes wastewater occurs occasionally during summer season (38 degrees C) due to the instability of nitrification process. The objective of this study was to examine why the nitrification process is unstable especially in summer. Various parameters such as pH, temperature, nutrients and pollutants were examined in batch experiments using activated sludge and wastewater obtained from a full-scale cokes wastewater treatment facility. Batch experiments showed that nitrification rate of the activated sludge was faster in summer (38 degrees C) than in spring or autumn (29 degrees C) and the toxic effects of cyanide, phenol and thiocyanate on nitrification were reduced with increasing temperature. Meanwhile, experiment using continuous reactor showed that the reduction rate in nitrification efficiency was higher at 38 degrees C than at 29 degrees C. In conclusion, the instability of full-scale nitrification process in summer might be mainly due to washing out of nitrifiers by fast growth of competitive microorganisms at higher temperature under increased concentrations of phenol and thiocyanate.

The dead biomass of the brown seaweed, Ecklonia sp., is capable of reducing toxic Cr(VI) into less toxic or nontoxic Cr(III). However, little is known about the mechanism of Cr(VI) reduction by the biomass. The objective of this work was to develop a kinetic model for Cr(VI) biosorption, for supporting our mechanism. The reduction rate of Cr(VI) increased with increasing total chromate concentration, [Cr(VI)], and equivalent concentration of organic compounds, [OCs], and decreasing solution pH. It was found that the reduction rate of Cr(VI) was proportional to [Cr(VI)] and [OCs], suggesting the simple kinetic equation -d[Cr(VI)]/dt=k[Cr(VI)][OCs]. When considering the consumption of organic compounds due to the oxidation by Cr(VI), an average rate coefficient of 9.33 (+/-0.65)microM(-1)h(-1) was determined, at pH 2. Although the function of the pH could not be expressed in a mechanistic manner, an empirical model able to describe the pH dependence was obtained. It is expected that the developed rate equation could likely be used for design and performance predictions of biosorption processes for treating chromate wastewaters.

Multi-dimensional proteomic analyses provide different layers of protein information, including protein abundance and post-translational modifications. Here, we report an integrated analysis of protein expression, phosphorylation and N-glycosylation by serial enrichments of phosphorylation and N-glycosylation (SEPG) from the same tissue samples. On average, the SEPG identified 142,106 unmodified peptides of 8,625 protein groups, 18,846 phosphopeptides (15,647 phosphosites) and 4,019 N-glycopeptides (2,634 N-glycosites) in tumor and adjacent normal tissues from three gastric cancer patients. The combined analysis of these data showed that the integrated analysis additively improved the coverages of gastric cancer-related protein networks; phosphoproteome and N-glycoproteome captured predominantly low abundant signal proteins and membranous or secreted proteins, respectively, while global proteome provided abundances for general population of the proteome. Therefore, our results demonstrate that the SEPG can serve as an effective approach for multi-dimensional proteome analyses and the holistic profiles of protein expression and PTMs enabled improved interpretation of disease-related networks by providing complementary information.

The aim of the present study was to investigate the effects of tristetraprolin (TTP) on the vascular endothelial growth factor (VEGF) mRNA and protein expression levels in retinal pigment epithelial cells under hypoxic conditions, and to consider the possibility of using TTP as a novel treatment tool for neovascular age‑related macular degeneration (AMD). Overexpression of TTP reduced the expression and secretion levels of VEGF in ARPE‑19 cells under hypoxic conditions. TTP destabilized the VEGF mRNA by binding to adenosine and uridine‑rich elements regions in its 3'‑untranslated region. Furthermore, conditioned medium (CM) from TTP‑overexpressing ARPE‑19 cells suppressed the tube formation in human umbilical vein endothelial cells compared with hypoxic CM. These findings indicate that regulation of TTP expression may be a promising therapeutic tool for neovascular AMD, however, further research is required.

A new scheme of robust adaptive partial least squares (PLS) method was proposed for the purpose of prediction and monitoring of an industrial wastewater treatment process that has highly complex and time-varying process dynamics. The essential feature of this method is that all incoming process data are preliminarily screened on the basis of a combined monitoring index and each observation identified as an outlier is simply eliminated (hard threshold) or suppressed by using a weight function (soft threshold) prior to model update. To elucidate the feasibility of the proposed scheme, various PLS modeling approaches, including conventional ones, were evaluated and their results were compared with each other. While the conventional approaches clearly revealed their limitations such as the inflexibility of the model to process changes and the misleading model update by high leverage outliers, most robust adaptive PLS approaches based on the proposed scheme exhibited fairly good performances both in the predic...

Three papers published during recent 2 years in Journal of Hazardous Materials made a mistake in analyzing chromium species in aqueous solution, resulting in incorrect elucidation of Cr(VI) biosorption; the Cr(VI) was removed from aqueous solution systems by 'anionic adsorption'. However, it has been proved that Cr(VI) is easily reduced to Cr(III) by contact with organic materials under acidic conditions because of its high redox potential value (above +1.3 V at standard condition). Therefore, it is strongly possible that the mechanism of Cr(VI) removal by biomaterials or biomaterial-based activated carbons is not "anionic adsorption" but "adsorption-coupled reduction". Thus, for researches of Cr(VI) biosorption, researchers have to analyze not only Cr(VI) but also total Cr in aqueous solution and to check the oxidation state of chromium bound on the biomaterials or activated carbons.

Water network synthesis has been employed to conserve water resources and reduce freshwater costs for the sake of sustainable development. However, the previous economic evaluations of water network systems did not comprehensively include all of the tradeoffs incurred in water network synthesis. The objective of this work was to evaluate the economic feasibility of a water network system using the net present value (NPV) method and estimate the principal cost and benefit contributors to its NPV. The procedure used for the economic evaluation consisted of water network synthesis, water system design, the estimation of the incremental costs and benefits, and the application of the NPV method. A total of 10 water-using operations in the steel and iron industry suffering from the shortage of water were used to evaluate the profitability of a water network system. The water network system was optimized by minimizing the freshwater consumption rates through nonlinear mathematical programming. This water network...

Partial least squares (PLS) has been extensively used in process monitoring and modeling to deal with many, noisy, and collinear variables. However, the conventional linear PLS approach may be not effective due to the fundamental inability of linear regression techniques to account for nonlinearity and dynamics in most chemical and biological processes. A hybrid approach, by combining a nonlinear PLS approach with a dynamic modeling method, is potentially very efficient for obtaining more accurate prediction of nonlinear process dynamics. In this study, neural network PLS (NNPLS) were combined with finite impulse response (FIR) and auto-regressive with exogenous (ARX) inputs to model a full-scale biological wastewater treatment plant. It is shown that NNPLS with ARX inputs is capable of modeling the dynamics of the nonlinear wastewater treatment plant and much improved prediction performance is achieved over the conventional linear PLS model.

In this study, the removal of Cr(VI) was examined in a binary aqueous system containing Ni(II), and the competitive interaction between them was successfully modeled. The removal rate of Cr(VI) was unaffected by the presence of Ni(II). However, in an equilibrium state, the uptake of total Cr or Ni(II) was decreased in the presence of the other metal. The mono- and multi-component Langmuir adsorption models clearly represented the uptake behavior of these metals.

The optimal timing of elicitation was determined for the production of benzophenanthridine alkaloids (BPAs) by Eschscholtzia californica cell culture. Upon elicitation, 7-day old cells produced more alkaloids than 14-day old cells (5.1 times for sanguinarine and 2.7 times for dihydrosanguinarine). We presumed that these alkaloids are growth-rate-associated secondary metabolites in E. californica cell culture. Although the specific productivity of alkaloids were higher in 7-day old culture, the total cell mass of 7-day old culture was about half that of 14-day old culture. In order to increase the overall productivity, sucrose was added to the 14-day old culture before the addition of elicitor. By this way, cells in the stationary phase (14-day old culture) could be switched to the cells in the logarithmic growth phase (similar to 7-day old culture). Total production of alkaloids was increased by adding sucrose; especially the production of sanguinarine was increased as high as 5.7 times of the control. To find out the protein level changed by the elicitation, proteins extracted from whole cell were separated by using two-dimensional gel electrophoresis. The patterns of the gels were different and little correlation among the proteins could be observed. And Western blotting was employed to check the expression level of selected five enzymes, these enzymes believed to be involved in BPAs production, resulting in up-regulated with elicitor addition.

Brown seaweed Ecklonia biomass was used for the treatment of electroplating wastewater that contains chromium and zinc ions. Batch experiments showed that Cr(VI) was removed from the wastewater through reduction to Cr(III) by contact with the biomass, whereas Cr(III) and Zn(II) were removed through adsorption to the binding sites of the biomass. Among various parameters, the solution pH most significantly affected the biosorptive capacity of the biomass. As the solution pH increased, the removal efficiency of Cr(VI) decreased, whereas that of Cr(III) and Zn(II) increased, for pH

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the soil environment, and considered to be hazardous due to their toxic and carcinogenic properties. Intermediates accumulation during PAHs degradation significantly alters the overall biodegradation rate and toxicity of the soil environment. The biodegradation pathway of phenanthrene, a 3-ring PAH, consisting of 14 enzymatic steps was analyzed to determine the release pattern of the intermediates by mathematical calculation of permeability using a membrane transport model. The intermediates with high permeability such as 1-hydroxy-2-naphthoic acid were consistent with the compounds frequently observed in laboratory or field in the literature.

Biological hydrogen production by the green alga Chlamydomonas reinhardtii under sulfur-deprived conditions has attracted great interest due to the fundamental and practical importance of the process. The photosynthetic hydrogen production rate is dependent on various factors such as strain type, nutrient composition, temperature, pH, and light intensity. In this study, physicochemical factors affecting biological hydrogen production by C. reinhardtii were evaluated with response surface methodology (RSM). First, the maximum specific growth rate of the alga associated with simultaneous changes of ammonium, phosphate, and sulfate concentrations in the culture medium were investigated. The optimum conditions were determined as NH(4+) 8.00 mM, PO(4)(3-) 1.11 mM, and SO(4)(2-) 0.79 mM in Tris-acetate-phosphate (TAP) medium. The maximum specific growth rate with the optimum nutrient concentrations was 0.0373 h(-1). Then, the hydrogen production rate of C. reinhardtii under sulfur-deprivation conditions was investigated by simultaneously changing two nutrient concentrations and pH in the medium. The maximum hydrogen production was 2.152 mL of H(2) for a 10-mL culture of alga with density of 6 x 10(6) cells mL(-1) for 96 h under conditions of NH(4)(+) 9.20 mM, PO(4)(3-) 2.09 mM, and pH 7.00. The obtained hydrogen production rate was approximately 1.55 times higher than that with the typical TAP medium under sulfur deficiency.

The biomass of the brown seaweed, Ecklonia sp., is capable of reducing Cr(VI) to Cr(III). However, very little is known about the mechanism of Cr(VI) reduction by the biomass. The aims of the present investigation were to enhance the Cr(VI)-reducing capacity of the biomass using various chemical treatments and to elucidate the mechanisms governing Cr(VI) reduction. Among the various chemical treatments, acid-treatment showed the best performance with regards the improvement of Cr(VI) removal from the aqueous phase, while organic solvent-treatment significantly improved the removal efficiency of total Cr in the equilibrium state. Based on FTIR study, the biomass was subjected to chemical modification of its amino and carboxyl groups, to examine their roles in the Cr(VI) removal from the aqueous phase. Methylation of the amino group significantly decreased the Cr(VI) removal rate, but amination of the carboxyl group significantly increased the Cr(VI) removal rate. Meanwhile, esterification of the carboxyl group and carboxylation of the amino group decreased the Cr(VI) removal rate, but the former showed a more negative effect than the latter. These findings indicated that the amino and carboxyl groups take part in the Cr(VI) removal from the aqueous phase. In conclusion, mechanisms for direct and indirect Cr(VI) removal are proposed, and some aspects for the application of this biomass to Cr(VI) detoxification are discussed.

The removal of hexavalent chromium from aqueous solution was carried out in batch experiments using dead biomass of four fungal strains – Aspergillus niger , Rhizopus oryzae , Saccharomyces cerevisiae and Penicillium chrysogenum . All of these dead fungal biomass completely removed Cr(VI) from aqueous solutions, that of R . oryzae being the most effective. Cr(VI) was removed from aqueous solutions by the reduction to Cr(III) when it contacted with the biomass. The removal rate of Cr(VI) increased with a decrease in pH or with increases of Cr(VI) and biomass concentrations. In particular, the removal rate of Cr(VI) was proportional to total chromate concentration [Cr(VI)], and equivalent concentration of organic compounds [OC], suggesting a simple rate equation in a form of d[Cr(VI)]/d t = − k [Cr(VI)][OC]. This model fitted well with the experimental data obtained at pH 2, supporting the mechanism that Cr(VI) is removed via a redox reaction. From the practical view point, the abundant and inexpensive dead fungal biomass could be used for the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).

To explore the complex dynamics of a full-scale anaerobic filter process treating the wastewater from a purified terephthalic acid manufacturing industry, a new modeling approach based on a moving-window-adaptive neural network is proposed. The essential feature of this modeling approach is that the neural network model is automatically updated whenever a new data block is available so that it can effectively capture the slowly changing process dynamics. To elucidate the advances of the proposed method, four different modeling approaches combined with the concepts of autoregressive with exogenous (ARX) input and a finite impulse response model were evaluated and compared. During each model identification process, a modified cross-validation technique was used to avoid the overfitting problem of a neural network. Among the tested models, a moving-window-adaptive ARX neural network model showed the best prediction ability with the smallest validation error. To investigate the feasibility of this model, vari...