bluuebunny/crossref_metadata_2025 huggingface dataset:
IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C: International Federation of Clinical Chemistry and Laboratory Medicine (IFCC): Scientific Division, Committee on Reference Systems for Enzymes (C-RSE): Part 8. Reference procedure for the measurement of catalytic concentration of α-amylase: [α-Amylase: 1,4-α-D-glucan 4-glucanohydrolase (AMY), EC 3.2.1.1]
Authors: Schumann G. , Aoki R. , Ferrero C.A. , Ehlers G. , Férard G. , Gella F.-J. , Jørgensen P.J. , Kanno T. , Kessner A. , Klauke R. , Kytzia H.-J. , Lessinger J.-M. , Miller W.G. , Nagel R. , Pauwels J. , Schimmel H. , Siekmann L. , Weidemann G. , Yoshida K. , Ceriotti F.
Published: September 2006

This paper is the eighth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2. Reference procedure for the measurement of catalytic concentration of creatine kinase; Part 3. Reference procedure for the measurement of catalytic concentration of lactate dehydrogenase; Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase Part 6. Reference procedure for the measurement of catalytic concentration of γ-glutamyltransferase; Part 7. Certification of four reference materials for the determination of enzymatic activity of γ-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase at 37°C. The procedure described here is deduced from the previously described 30°C IFCC reference method. Differences are tabulated and commented on.

Clin Chem Lab Med 2006;44:1146–55.
Towards the Development of Accelerated Methods for Assessing the Durability of Wood Plastic Composites
Authors: Silva A , Gartner BL , Morrell JJ
Published: September 2006

While wood plastic composites have gained an increasingly large share of the market for decks and other outdoor structures, there are many questions about the long-term potential for biodeterioration of these materials. While the plastic does appear to retard moisture uptake, thereby slowing the rate of degradation, a number of laboratory and field studies have found that fungal attack can occur. One approach to addressing this issue is to alter the WPC by either adding biocides or altering structure to retard fungal attack; however, assessing the durability of these new materials poses a challenge because of the lack of standard methods for accelerating the decay. In this study, we explored the use of agar, soil, vermiculite, and liquid media for accelerating the decay rates of pine and maple based WPCs under laboratory conditions. Agar and soil proved to be the most effective substrates, although the agar systems were far easier to prepare, but the degree of fungal attack was a function of moisture uptake. Thicker samples, which tended to absorb moisture more slowly, tended to have sharply lower weight losses. Maple WPCs tended to be more susceptible to fungal attack than those made with pine, suggesting that altering the wood source could be one simple method for enhancing durability without supplemental biocides.
Functional Dissection of the Tol2 Transposable Element Identified the Minimal cis-Sequence and a Highly Repetitive Sequence in the Subterminal Region Essential for Transposition
Authors: Urasaki Akihiro , Morvan Ghislaine , Kawakami Koichi
Published: September 2006

The Tol2 element is a naturally occurring active transposable element found in vertebrate genomes. The Tol2 transposon system has been shown to be active from fish to mammals and considered to be a useful gene transfer vector in vertebrates. However, cis-sequences essential for transposition have not been characterized. Here we report the characterization of the minimal cis-sequence of the Tol2 element. We constructed Tol2 vectors containing various lengths of DNA from both the left (5′) and the right (3′) ends and tested their transpositional activities both by the transient excision assay using zebrafish embryos and by analyzing chromosomal transposition in the zebrafish germ lineage. We demonstrated that Tol2 vectors with 200 bp from the left end and 150 bp from the right end were capable of transposition without reducing the transpositional efficiency and found that these sequences, including the terminal inverted repeats (TIRs) and the subterminal regions, are sufficient and required for transposition. The left and right ends were not interchangeable. The Tol2 vector carrying an insert of >11 kb could transpose, but a certain length of spacer, <276 but >18 bp, between the left and right ends was necessary for excision. Furthermore, we found that a 5-bp sequence, 5′-(A/G)AGTA-3′, is repeated 33 times in the essential subterminal region. Mutations in the repeat sequence at 13 different sites in the subterminal region, as well as mutations in TIRs, severely reduced the excision activity, indicating that they play important roles in transposition. The identification of the minimal cis-sequence of the Tol2 element and the construction of mini-Tol2 vectors will facilitate development of useful transposon tools in vertebrates. Also, our study established a basis for further biochemical and molecular biological studies for understanding roles of the repetitive sequence in the subterminal region in transposition.
Potential Treatment of Cerebral Global Ischemia with Oct-4+ Umbilical Cord Matrix Cells
Authors: Jomura Sachiko , Uy Marc , Mitchell Kathy , Dallasen Renee , Bode Claudia J. , Xu Yan
Published: September 2006

Potential therapeutic effects of Oct-4-positive rat umbilical cord matrix (RUCM) cells in treating cerebral global ischemia were evaluated using a reproducible model of cardiac arrest (CA) and resuscitation in rats. Animals were randomly assigned to four groups: A, sham-operated; B, 8-minute CA without pretreatment; C, 8-minute CA pretreated with defined media; and D, 8-minute CA pretreated with Oct-4+ RUCM cells. Pretreatment was done 3 days before CA by 2.5-μl microinjection of defined media or approximately 104 Oct-4+ RUCM cells in left thalamic nucleus, hippocampus, corpus callosum, and cortex. Damage was assessed histologically 7 days after CA and was quantified by the percentage of injured neurons in hippocampal CA1 regions. Little damage (approximately 3%–4%) was found in the sham group, whereas 50%–68% CA1 pyramidal neurons were injured in groups B and C. Pretreatment with Oct-4+ RUCM cells significantly (p < .001) reduced neuronal loss to 25%–32%. Although the transplanted cells were found to have survived in the brain with significant migration, few were found directly in CA1. Therefore, transdifferentiation and fusion with host cells cannot be the predominant mechanisms for the observed protection. The Oct-4+ RUCM cells might repair nonfocal tissue damage by an extracellular signaling mechanism. Treating cerebral global ischemia with umbilical cord matrix cells seems promising and worthy of further investigation.
Stage-Specific Conditional Mutagenesis in Mouse Embryonic Stem Cell-Derived Neural Cells and Postmitotic Neurons by Direct Delivery of Biologically Active Cre Recombinase
Authors: Haupt Simone , Edenhofer Frank , Peitz Michael , Leinhaas Anke , Brüstle Oliver
Published: September 2006

Conditional mutagenesis using Cre/loxP recombination is a powerful tool to investigate genes involved in neural development and function. However, the efficient delivery of biologically active Cre recombinase to neural cells, particularly to postmitotic neurons, represents a limiting factor. In this study, we devised a protocol enabling highly efficient conditional mutagenesis in ESC-derived neural progeny. Using a stepwise in vitro differentiation paradigm, we demonstrate that recombinant cell-permeable Cre protein can be used to efficiently induce recombination at defined stages of neural differentiation. Recombination rates of more than 90% were achieved in multipotent pan-neural and glial precursors derived from the Z/EG reporter mouse ESC line, in which Cre recombination activates enhanced green fluorescent proteinexpression. Recombined precursor cells displayed a normal phenotype and were able to differentiate into neurons and/or glial cells, indicating that Cre treatment has no overt side effects on proliferation and neural differentiation. Our data further demonstrate that recombination via Cre protein transduction is not restricted to dividing cells but can even be applied to postmitotic neurons. The ability to conduct Cre/loxP recombination at defined stages of stem cell differentiation in an expression-independent manner provides new prospects for studying the role of individual genes under stringent temporal control.
Effect of surface functional group on adsorption of organic pollutants on hexagonal mesoporous silicate
Authors: Patiparn P. , Takizawa S.
Published: September 2006

Hexagonal mesoporous silicates (HMSs) are synthetic silicate materials that have uniform mesopores, comparatively large surface areas, and uniform surface functional groups, which lead to higher adsorption selectivity. Selective adsorption characteristics of HMSs for six types of organic pollutants (2,4-d, mecoprop, 4-chlorophenol, toluene, dichloroacetic acid, and thioflavin T) from synthetic wastewater were investigated. Five different types of HMSs were synthesized by surfactant-templating methods, and three of them were subsequently grafted with organic surface functional groups, i,e. n-octyldimethyl-, 3-aminopropyltriethoxy-, and 3-mercaptopropyl-groups. Titanium-substituted HMS was also made in the same way as pristine HMS. Increasing hydrophobicity of HMSs did not always enhance adsorption of hydrophobic adsorbates, such as toluene. Grafted organic functional groups changed surface charge, which enhanced electrostatic force between HMSs and ionic pollutants. Negatively charged contaminants, i.e. 2,4-d, mecoprop and dichloroacetic acid, were more readily adsorbed on positively charged AM-HMS by electrostatic interaction. Hydrogen bonding and van der Waals interaction between adsorbents and adsorbates, as well as combination of these forces, also enhanced the adsorption capacities of HMSs. In addition to the electrostatic interaction, a cationic dye, thioflavin T, was adsorbed on the surfaces due to hydrogen bonding and van der Waals interaction for hydrophilic surfaces and hydrophobic surfaces, respectively.
Evaluation of microfiltration system performance as pre-treatment for reverse osmosis seawater desalination through pilot-plant operation
Authors: Kim S.H. , Yoon J.S. , Yoon C.H.
Published: September 2006

This study was undertaken to evaluate the suitability of microfiltration (MF) as pre-treatment for reverse osmosis (RO) seawater desalination to treat the seawater suffering from red-tide contamination using long-term operation of pilot plant. The one and a half year pilot MF operation had two objectives: stable production of the flow rate of 5 m3/h and acceptable water quality (SDI less than 3). The pilot plant operation revealed that the MF system successfully produced the target flow rate despite red-tide contamination of the seawater. The average flow rate of 5.2 m3/h was obtained at the average operating pressure of 0.53 bar. However, the MF system failed to achieve the target flow rate at red-tide bloom. When red-tide bloom occurred the chlorophyll-a concentration became 136 mg/m3, the flow rate decreased to half of the target, and energy consumption became extremely high. Subsequently, the operation was stopped. According to the relationship between the flow rate of the MF system and chlorophyll-a concentration developed in this study, it would be desirable to stop the MF operation at chlorophyll-a concentration of 57 mg/m3. The MF system produced acceptable quality water for RO feeding. The SDI of the MF treated was consistently less than 3. The MF system consumed 0.5 KWh of energy to produce 1 m3/h of MF treated, if the data during the red-tide bloom were excluded. Extra equipment (intake pump, control system, monitoring system, air conditioner) caused higher energy consumption than expected.
A genetic algorithm-based fuzzy multi-objective programming approach for environmental water allocation
Authors: Yang W. , Sun D.Z.
Published: September 2006

A fuzzy multiobjective-programming model was presented to determine appropriate environmental flow allocation in urban rivers. An integrated nonlinear fuzzy membership function, that represents a broader implication in fuzzy decision-making, was regarded as the general objective and genetic algorithm became an essential tool in search for the global optimal solution. A case study of optimal allocation for environmental water requirements in the Liming River Basin, Daqing, demonstrates the capability of the fuzzy multiobjective model based on fuzzy decision theories to work suitably in water environmental management in a river basin.
Influence of porosity and surface chemistry of commercially available powdered activated carbons for the removal of dissolved organic carbon
Authors: Treguer R. , Couvert A. , Wolbert D. , Suty H. , Randon G.
Published: September 2006

More restricting legislation on Dissolved Organic Carbon (DOC) content in drinking water, especially when applied to waters with high DOC contents and low turbidity, urges the industry to improve, all along the processes, the removal of dissolved organic matter (DOM) in drinking water resources. This work focused on the characterisation of the performances of commercially available powdered activated carbons (PAC). Equilibrium isotherms were carried out on pre-treated water, i.e. after coagulation, flocculation and sedimentation. In order to determine the efficiency of the PAC, the DOM content was estimated through DOC and UV absorbance measures, as well as being characterised by size exclusion chromatography. The various experiments carried out showed some differences in the adsorption capacity, depending on their pore distribution and surface chemistry. The maximum removal ratio reached 82% and 45% for DOC and SUVA respectively. The isotherm equilibrium results can be used to define several kinds of DOC fractions, which were modelled by the Freundlich equation. Finally, the SEC chromatograms showed that the pore size distribution of the activated carbons affected significantly the compound size distribution of the removed DOM.
Evaluation of 16S-PCR detection of Dehalococcoides at two chloroethene-contaminated sites
Authors: Schmidt K.R. , Stoll C. , Tiehm A.
Published: September 2006

The aim of this study was to evaluate and optimize the detection of Dehalococcoides, the only group of bacteria reported so far that reductively dechlorinates tetrachloroethene to ethene. Samples were taken from microcosms and groundwater of two tetra- and trichloroethene-contaminated sites differing significantly in their pollutant profiles. At the Killisfeld site, cis-1,2-dichloroethene, vinyl chloride and ethene are detected in the plume indicating complete reductive dechlorination. At the Frankenthal site, cis-1,2-dichloroethene is predominating and ethene is not detected. The sensitivity of Dehalococcoides detection by 16S-PCR (polymerase chain reaction) in groundwater was increased by optimizing the DNA-extraction and the protocols for direct and nested PCR. Direct PCR made the visualization of Dehalococcoides growth during complete degradation of tetrachloroethene in microcosms possible. With nested PCR Dehalococcoides were detected in all seven groundwater samples taken in the plume from the Killisfeld site, but not in any of eleven samples taken at the Frankenthal site. Thus, 16S-PCR detection of Dehalococcoides represents a quick and easy means to assess the potential of complete reductive dechlorination in microcosms and field samples.
Ion exchange process in the presence of high sulphate concentration: resin regeneration and spent brine reuse
Authors: Baciocchi R. , Chiavola A.
Published: September 2006

This paper provides new insights on the regeneration step of an ion exchange process for the treatment of surface and ground water characterized by high sulphate concentration. Repeated regeneration of ion exchange resin with a sodium chloride solution (brine) did not alter the resin performances with respect to the fresh one. Besides, neither the sodium chloride concentration of the brine, which was varied between 1 and 3 M, nor the presence of sulphates at concentrations up to 20 g/L in the brine, did notably affect the regeneration efficiency. The brine was effectively treated by adding calcium or barium chloride, in order to remove the sulphates and re-establish the original chloride concentration. Calcium chloride was allowed to obtain up to 70% sulphate precipitation, whereas an almost 100% precipitation efficiency was obtained when barium chloride was used. The precipitation step was described by a model based on the mass action, coupled to the Bromley model for the description of the non-ideal behaviour of the electrolytic solution. This model was shown to give correct, or at least conservative, estimates of the equilibrium sulphate concentration when either calcium or barium chloride was used as precipitating agent.
Development of a closed loop stripping analysis using solid-phase microextraction to analyze geosmin and MIB in drinking water
Authors: (Mel) Suffet I.H. , Bruchet A. , Young C.C.
Published: September 2006

A novel analytical method, solid phase microextraction (SPME) coupled with closed loop stripping analysis (CLSA), was introduced for the analysis of MIB and geosmin at nanogram per liter concentration levels. The optimum CLSA/SPME analysis conditions of 65 °C, 60-minute extraction time, and 0.5 M sodium sulfate were determined from a statistical design. The individual Kfw of MIB and geosmin from CLSA/SPME method was 4.21 and 4.85, and resulted an order of magnitude greater than the Kfw obtained from direct SPME method. A detection limit of 10 ng/L of MIB and geosmin was achieved by GC-MS with CLSA/SPME with a polyacrylate phase. Overall, CLSA/SPME provides a fast, solvent-free, and less labor intensive method compared to the standard CLSA. The CLSA/SPME method is a valuable alternative method for the analysis of taste-and-odor causing compounds in drinking water.
Application of modern financial portfolio theory to water resource portfolios
Authors: Beuhler M.
Published: September 2006

Modern portfolio theory developed for financial markets has application to water resource portfolios. It can help make decisions on how to optimally meet future water needs. By explicitly considering volatility and correlations among water resource alternatives, rational resource combinations can be selected. It enables water planners to decide how much to invest in traditional ways to meet water needs such as surface and groundwater supplies and to decide how much to invest in non-traditional, more expensive supplies such as recycling, conservation, and desalination. It enables explicit risk reduction of systematic risks due to the hydrologic cycle such as drought, and non-systematic risks such as water quality, climate, and energy. This paper describes a qualitative application of modern portfolio theory to water resources. Quantitative application will require the development of additional data.
A review of participatory test and evaluation approaches for water management
Authors: Muro M. , Jeffrey P.
Published: September 2006

Past failures in designing and implementing successful natural resource management policies and practices have taught us that water resource management cannot be based solely on science and technical expertise. It is increasingly recognized as a fundamentally social and political process as it affects the stakeholders, their environment, and their livelihoods. The challenge is to identify responses that will be adopted rather than something that works. Involving stakeholders in the design and evaluation of new management options, technologies, and policies seems to be a promising approach to ensure their success in terms of acceptance and deployment by end-users. In order to come up with feasible, effective, and accepted environmental management solutions, environmental planning and decision-making processes have to be interactive and iterative. This paper identifies key issues in participatory test and evaluation (PTE) and offers a cursory overview of approaches, methods, and tools for participatory evaluation. An outline method for PTE in the water sector is proposed and conclusions drawn as to appropriate deployment.
Determination of design capacity for water transmission systems based on the characteristics of regional peak factors
Authors: Hyun I.-H. , Dockko S. , Lee C.-I.
Published: September 2006

The design capacity of a water supply can be derived from the peak factor. In this research, four different methods were used to determine the peak factor more precisely. Applying Method 1 could result in the design capacity being underestimated, by designing the lower part of the pipeline to apply the peak factor to the whole area. Applying Method 2 could overestimate it by 10–30% in the upper part of the pipeline by dividing the sum of the regional peak factors according to the ratio of peak day demand to the region. Applying Method 3 underestimates the design capacity in small areas, while it could overestimate it in large areas. Finally, Method 4 gives optimum results for the peak factor for estimating the design capacity.
Integrated water resources management on the Tonle Sap Lake, Cambodia
Authors: Varis O. , Kummu M. , Keskinen M. , Sarkkula J. , Koponen J. , Heinonen U. , Makkonen K.
Published: September 2006

Integrated Water Resources Management has been identified as one of the basic water resources related policy approaches in several recent important commitments and recommendations including the Johannesburg Summit and World Water Forums. Recognizing that IWRM is largely still a theoretical concept with not much sound scientific research, our objective is to investigate how the IWRM process in the Mekong Basin is institutionalised, and implemented in practice. We focus on the Cambodia's Great Lake, the Tonle Sap. Of particular interest are the bottlenecks of IWRM, both those that are within the water sector and those that relate to various, more general development tendencies.
Effect of preozonation on characteristics of algae cells and algae-derived organic matter (AOM) with respect to their removal by coagulation
Authors: Ma J. , Fang J.Y. , Wang L.N. , Guo J. , Chen Z.L.
Published: September 2006

The presence of algae cells and algae-derived organic matter (AOM) including extracellular organic matter (EOM) and intracellular organic matter (IOM) has a significant impact on drinking water treatment. Jar tests were conducted with or without preozonation to assess the effect of preozonation on the characteristics of AOM and algae cells with respect to their removal by the following coagulation process. Algae cells and AOM were analyzed by photomicrography, particle size distribution, UV absorbance scanning, HPSEC-UV and batch ultrafiltration (UF). Micrographs and particle size distribution of algae cells with or without ozonation showed that ozonation could oxidize chlorophyll in algae cells, damage algae cells to varying degrees and increase the settling property of algae cells. UV absorbance scanning showed there were more protein-like substances in AOM. Molecular weight (MW) distribution revealed that IOM and EOM had almost the same species of organic matter: the major species of IOM was organic matter with high MW and EOM was organic matter with lower MW. Overall, preozonation can enhance the coagulation process by greatly increasing the removal efficiency of algae cells and particles. At the same time, preozonation is not very effective on enhancing AOM removal, for it is limited in improving the removal rate of EOM, and it can cause the release of IOM.
The efficiency and mechanism of the degradation of nitrobenzene in aqueous solution by O3/H2O2
Authors: Shen J. , Chen Z. , Li X. , Qi F. , Ye M.
Published: September 2006

Selecting nitrobenzene (NB) as the model pollutant, this paper investigated the efficiency and mechanism of the degradation of NB in aqueous solution by O3/H2O2. The effects of pH value, H2O2 dose and the inhibitor or accelerant of •OH on the removal rate of NB were studied. H2O2 could obviously improve the ozonation decay rate of NB below pH 7. When H2O2 dose increased from 1.0 mg/L to 4.0 mg/L, the removal rate of NB was remarkably enhanced. However, as H2O2 dose increased from 4.0 mg/L to 20 mg/L, the removal efficiency of NB decreased. Different masses of H2O2 were yielded in different reaction phases of the single ozonation system. Both single ozonation systems and H2O2-catalysed ozonation could not observably reduce the TOC. During the process of NB degradation, organonitrogen was almost completely converted to nitrate and the pH value reduced significantly. Results of HPLC-MS and GC-MS showed that the main intermediate products were phenolic compounds and carbonyl compounds. Finally, a possible reaction pathway of the catalytic ozonation of NB is proposed. It had been found that the catalytic ozonation of NB could be divided into two steps. First, hydroxyl radical attacked phenyl ring, and then the ring opened, forming into various aliphatic compounds or being mineralized to inorganic compounds.
Analysis of particle numbers, size and composition in drinking water transportation pipelines: results of online measurements
Authors: Verberk J.Q.J.C. , Hamilton L.A. , O'Halloran K.J. , van der Horst W. , Vreeburg J.
Published: September 2006

The particulate water quality in a distribution network is not always constant but can deteriorate over time. Discolouration problems can occur, especially in distribution systems with a low flow rate. Until now, particulate water quality in the distribution network has been mainly monitored by measuring the turbidity. However, as turbidity is an indirect measurement method, it does not give quantitative and qualitative information about the water quality, and therefore a more advanced approach was used in this research. Several particle counters have been used simultaneously to measure the particulate water quality at different locations in a transportation system. It was found that larger particles were present further away from the treatment location, although these sized particles were not present directly after treatment. The particulate water quality in the transportation system was also assessed by filtering time integrated large volume water samples. Both organic and inorganic measurements were used to characterise the particle composition. The results of the analysis show that the particulate water quality changed in the transportation system.
Application of computational fluid dynamics (CFD) to ozone contactor optimization
Authors: Li J. , Zhang J. , Miao J. , Ma J. , Dong W.
Published: September 2006

Many approaches have been used to model the performance and efficiency of ozone contactors based on some assumptions to characterize the backmixing in fluids. Recently, computational fluid dynamics (CFD) technique has been proposed to simulate and optimize ozone contactors by calculating residence time distribution of fluid. To improve the ozone contactor performance of Bijianshan Water Treatment Plant in Shenzhen in South China, CFD was used for simulation and development of new optimization measures. Results showed that the low depth/length ratio of the contactor chambers in the original design resulted in short circuiting and backmixing, with the T10/HRT being only 0.40. Installation of guide plates substantially reduced short circuiting and backmixing with a much higher T10/HRT (0.66), increased by 73% compared with the original design.
An approach to residual aluminium control at Nisiya purification plant, Water Works Bureau, Yokohama
Authors: Matsukawa S. , Itoho S. , Habuthu S. , Aizawa T.
Published: September 2006

In Yokohama Water Works Bureau, the target value for aluminium control in purified water is set to 0.05 mg/L. In this study, we examined the effects of pH and water temperature on the water solubility of aluminium during purification processes, and obtained a solubility curve of aluminium in water based on these parameters. The result indicated that the water solubility of aluminium increases as water temperature or pH increases. In addition, it was calculated from this solubility curve of aluminium in water, that the level of residual aluminium in purified water can be controlled at approx. 0.04–0.05 mg/L by adjusting pH of coagulated water to approx. 7.1–7.4 depending on water temperature. Furthermore, as a result of pH control according to actual coagulated water temperatures based on this assumption, it was demonstrated that the target value for aluminium control in purified water, (0.05 mg/L) is achievable.
Microbial fuel cells for wastewater treatment
Authors: Aelterman P. , Rabaey K. , Clauwaert P. , Verstraete W.
Published: September 2006

Microbial fuel cells (MFCs) are emerging as promising technology for the treatment of wastewaters. The potential energy conversion efficiencies are examined. The rates of energy recovery (W/m3 reactor) are reviewed and evaluated. Some recent data relating to potato-processing wastewaters and a hospital wastewater effluent are reported. Finally, a set of process configurations in which MFCs could be useful to treat wastewaters is schematized. Overall, the MFC technology still faces major challenges, particularly in terms of chemical oxygen demand (COD) removal efficiency.
Hydrogen limitation—a method for controlling the performance of membrane biofilm reactor for autotrophic denitrification of wastewater
Authors: Celmer D. , Oleszkiewicz J. , Cicek N. , Husain H.
Published: September 2006

Hydrogen-driven denitrification using the fiber membrane biofilm reactor (MBfR) was evaluated for consistent operation in tertiary wastewater treatment. The possibility of controlling the process rates, as well as biofilm parameters by supplying limited amounts of electron donor (hydrogen), was tested. Limiting the hydrogen supply proved to be efficient in controlling the biofilm growth and performance of the MBfR. Denitrification rates remained unchanged for both synthetic wastewater (SWW) and real municipal wastewater (MWW) effluent as well through the fluctuations in the substrate (NO3-N) concentration. The average denitrification rates were 0.50 (±0.02) g NO3-N per day per m2 for SWW and 0.59 (±0.04) g NO3-N per day per m2 for MWW. Biofilm density rather than thickness was the determining factor in substrate diffusion and biofilm sloughing, ultimately determining operating stability. Limited hydrogen supply assured constant volatile solids (VS) concentration in the biofilm. It was determined that VS/TS ratio higher than 0.25 assured stable biofilm operation. Decrease of VS/TS ratio below 0.25 led to shearing of the non-biological outer layers of the biofilm. The values of chemical oxygen demand (COD), volatile suspended solids (VSS) and total suspended solids (TSS) in the final effluent were stable and well below wastewater effluent guidelines. Substitutions of bicarbonate with gaseous carbon dioxide as the carbon source did not affect denitrification rates despite lower than optimum pH conditions.
Evaluation and testing of fine mesh sieve technologies for primary treatment of municipal wastewater
Authors: Rusten B. , Ødegaard H.
Published: September 2006

Fine mesh sieve technologies were tested in full scale at several municipal wastewater treatment plants. A screening test was used to characterize wastewater and establish the design criteria for the sieves. To achieve high removal efficiencies it was crucial to operate the sieves with a filter mat. Rotating belt sieves performed best in the full-scale tests. A small dose of cationic polymer and a static flocculator ahead of a rotating belt sieve achieved excellent results on a wastewater that was originally found unsuitable for primary treatment with fine mesh sieves. Simple screw presses dewatered the sludge from the sieves to typically 25–30% total solids. Using fine mesh sieves with <500 microns openings was found to normally be the most economical process for primary treatment.
Experimental and model-based evaluation of the role of denitrifying polyphosphate accumulating organisms at two large scale WWTPs in northern Poland
Authors: Makinia J. , Rosenwinkel K.-H. , Swinarski M. , Dobiegala E.
Published: September 2006

The capabilities of denitrifying Polyphosphate Accumulating Organisms (DPAOs) in two large-scale plants in northern Poland performing enhanced biological phosphorus removal (EBPR) were evaluated in this study. A series of batch tests with the process biomass aimed at the measurements of phosphate release (with artificial substrate and real wastewater) and subsequent phosphate uptake under anoxic/aerobic conditions. The process kinetics were predicted using ASM2d implemented in the GPS-X ver. 4.0.2 simulation package. The results from one experimental series (summer) were used for the model calibration, whereas the results from another series (spring) were used for the model validation. The model parameters were also accurately confirmed by predictions of the accompanying field measurements in the full-scale bioreactors. The experimental and simulation results revealed that a relatively small fraction of PAO could denitrify (ηNO3,PAO=0.32). The denitrification rates associated with the anoxic storage of PP and the anoxic growth of PAO only constituted 16.0–21.0% of the denitrification rates associated with the anoxic activity of “ordinary” heterotrophs.
Fermentative hydrogen production in packed-bed and packing-free upflow reactors
Authors: Li C. , Zhang T. , Fang H.H.P.
Published: September 2006

Fermentative hydrogen production from a synthetic wastewater containing 10 g/L of sucrose was studied in two upflow reactors at 26°C for 400 days. One reactor was filled with packing rings (RP) and the other was packing free (RF). The effect of hydraulic retention time (HRT) from 2 h to 24 h was investigated. Results showed that, under steady state, the hydrogen production rate significantly increased from 0.63 L/L/d to 5.35 L/L/d in the RF when HRT decreased from 24 h to 2 h; the corresponding rates were 0.56 L/L/d to 6.17 L/L/d for the RP. In the RF, the hydrogen yield increased from 0.96 mol/mol-sucrose at 24 h of HRT to the maximum of 1.10 mol/mol-sucrose at 8 h of HRT, and then decreased to 0.68 mol/mol-sucrose at 2 h. In the RP, the yield increased from 0.86 mol/mol-sucrose at 24 h of HRT to the maximum of 1.22 mol/mol-sucrose at 14 h of HRT, and then decreased to 0.78 mol/mol-sucrose at 2 h. Overall, the reactor with packing was more effective than the one free of packing. In both reactors, sludge agglutinated into granules. The microbial community of granular sludge in RP was investigated using 16S rDNA based techniques. The distribution of bacterial cells and extracellular polysaccharides in hydrogen-producing granules was investigated by fluorescence-based techniques. Results indicated that most of the N-acetyl-galactosamine/galactose-containing extracellular polysaccharides were distributed on the outer layer of the granules with a filamentous structure.
Predicting struvite formation for phosphorus recovery from human urine using an equilibrium model
Authors: Harada H. , Shimizu Y. , Miyagoshi Y. , Matsui S. , Matsuda T. , Nagasaka T.
Published: September 2006

Interest in phosphorus recovery from urine diverted from faeces has been growing recently. Phosphorus in urine can be precipitated out as struvite (MgNH4PO4•6H2O) with addition of magnesium salt under alkaline conditions. Struvite formation, however, should be more well understood for its practical application. We predicted the struvite formation with a development of a new equilibrium model. The model considered the formation of eight different kinds of precipitates, including struvite, with effects of ionic strength and temperature. In addition, experiments on struvite formation in urine were conducted for the model validation. The model prediction of struvite formation had good agreement with the experimental results. The optimum pH to form struvite was predicted to be 9.4–9.7. In order to precipitate 99% of phosphate in urine with 1.5 fold Mg concentration to PO4-P, the pH value was necessary to be more than 8.1 based on the model prediction.
Toxicity assessment of polycyclic aromatic hydrocarbons using an air-tight algal toxicity test
Authors: Chen C.Y. , Yan Y.K. , Yang C.F.
Published: September 2006

The existing toxicity data on the effects of polycyclic aromatic hydrocarbons (PAHs) on Pseudokirchneriella subcapitata (green alga) are quite insufficient. These data were derived using different test techniques (e.g. conventional batch test, closed-system test, semi-static test). The relative toxicity relationship for various PAHs is thus difficult to interpret. Consequently, the current toxicity database is insufficient and also inadequate for analyses of the effects of PAHs on P. subcapitata. This study evaluated the toxicity of eleven PAHs using an air-tight test technique. The relative toxicity relationship was determined on a uniform basis, and was different from the relationship based on current available data. P. subcapitata. was found to be more susceptible to PAHs than Daphnia magna, fathead minnow, and Scenedesmus subspicatus. Quantitative structure-activity relationship (QSAR) was established based on the chemical's hydrophobicity with R2 equal to 0.88. Photo-induced toxicity for various PAHs was also explored by exposing PAHs under UV-photoactivation. Toxicity of anthracene, benzanthrone, and benzo[a]anthracene was found to increase 3.5 to 25 times after UV exposure. Phototoxicity was observed when the HOMO-LUMO gap varied between 6.8 and 8.0 eV.
Bench- and pilot-scale sludge electrodewatering in a diaphragm filter press
Authors: Saveyn H. , Van der Meeren P. , Pauwels G. , Timmerman R.
Published: September 2006

Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents. In order to be energy efficient, it is shown that sludge should be dewatered by pressure dewatering to a high extent prior to electric field application, and a sufficient contact time for the electric field must be guaranteed. In order to realize these goals, a bench- and pilot-scale diaphragm filter press suited for electrodewatering were constructed for treatment of sewage and other types of sludges. It was shown that electrodewatering of sludge is a feasible technique, especially for biological sludge types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a moderate energy consumption. Depending on local market prices for investment, operating and sludge disposal costs, this technology may therefore lead to important savings in the sludge management process.
Filter clogging in coarse pore filtration activated sludge process under high MLSS concentration
Authors: Alavi Moghaddam M.R. , Guan Y. , Satoh H. , Mino T.
Published: September 2006

Coarse pore filtration activated sludge process is a type of hybrid process in which the secondary settling tank of the conventional activated sludge process is replaced by non- woven and coarse pore filter modules. The filter has pores, which are irregular in shape, and much bigger than micro-filtration membrane pores in size. The objective of the study is to find out the effect of the microbial community structure on filter clogging in the coarse pore filtration activated sludge process under high MLSS concentration in aerobic and anoxic/aerobic (A/A) conditions. Filter clogging started from day 65 and 70 in the A/A and aerobic process, respectively, but it was more severe in the A/A process compared to that in the aerobic process. EPS contents of sludge did not change significantly during the operation in both processes, and did not have a crucial effect on the observed filter clogging. There was no strong evidence for direct effect of the type and number of metazoa on filter clogging. The main difference between aerobic sludge and A/A sludge during the filter clogging period was the relative abundance of filamentous bacteria. According to the obtained results, it can be concluded that a higher presence of filamentous bacteria could reduce the severity of filter clogging in a coarse pore filtration activated sludge process.
New anaerobic process of nitrogen removal
Authors: Kalyuzhnyi S. , Gladchenko M. , Mulder A. , Versprille B.
Published: September 2006

This paper reports on successful laboratory testing of a new nitrogen removal process called DEAMOX (DEnitrifying AMmonium OXidation) for the treatment of strong nitrogenous wastewater such as baker's yeast effluent. The concept of this process combines the recently discovered ANAMMOX (ANaerobic AMMonium OXidation) reaction with autotrophic denitrifying conditions using sulfide as an electron donor for the production of nitrite within an anaerobic biofilm. The achieved results with a nitrogen loading rate of higher than 1, 000 mg/L/d and nitrogen removal of around 90% look very promising because they exceed (by 9–18 times) the corresponding nitrogen removal rates of conventional activated sludge systems. The paper describes also some characteristics of DEAMOX sludge, as well as the preliminary results of its microbiological characterization.
Photodegradation of perfluorooctanoic acid in water under irradiation of 254 nm and 185 nm light by use of persulfate
Authors: Chen J. , Zhang P.
Published: September 2006

The photodegradation of perfluorooctanoic acid (PFOA) in water using two types of low-pressure mercury lamps, one emitting 254 nm and the other emitting 254 nm and 185 nm, by use of persulfate (K2S2O8) as an oxidant was investigated. PFOA was significantly decomposed under irradiation of 185 nm light, while it was very slow and negligible under 254 nm light irradiation. This was due to its strong absorption of PFOA from deep UV-region to 220 nm and a weak absorption from 220–460 nm. The addition of K2S2O8 led to efficient PFOA decomposition and defluorination no matter what light irradiation. Sulfate radical anion (SO−4), generated by photolysis of K2S2O8, initiated the oxidation of PFOA. Under irradiation of 185 nm light, PFOA was jointly decomposed through 185 nm light photolysis and initiation of sulfate radical. However, under irradiation of 254 nm light, PFOA decomposition was only initiated by sulfate radical. PFOA decomposed and defluorinated much faster under oxygen atmosphere than under nitrogen atmosphere, which suggested that oxygen molecules played an important role in PFOA decomposition.
Development of chitosan-based granular adsorbents for enhanced and selective adsorption performance in heavy metal removal
Authors: Li N. , Bai R.
Published: September 2006

Novel chitosan-based granular adsorbents were developed for enhanced and selective separation of heavy metal ions. The research included the synthesis of chitosan hydrogel beads, the cross-linking of the hydrogel beads with ethylene glycol diglycidyl ether (EGDE) in a conventional and a novel amine-shielded method, the functionalization of the chitosan beads through surface grafting of polyacrylamide via a surface-initiated atom transfer radical polymerization (ATRP) method, and the examination of the adsorption performance of the various types of chitosan beads in the removal of heavy metal ions. It was found that chitosan beads were effective in heavy metal adsorption, the conventional cross-linking method improved the acidic stability of the beads but reduced their adsorption capacity, the novel amine-shielded cross-linking method retained the good adsorption capacity while it improved the acidic stability of the beads, and the grafting of polyacrylamide on chitosan beads not only enhanced the adsorption capacity but also provided the beads with excellent selectivity for mercury over lead ions. XPS analyses indicated that the adsorption of metal ions on chitosan beads was mainly attributed to the amine groups of chitosan, the novel amine-shielded cross-linking method preserved most of the amine groups from being consumed by the cross-linking process and hence improved the adsorption capacity of the cross-linked chitosan beads, and the many amide groups from the polyacrylamide grafted on the chitosan beads increased the adsorption capacity and also made possible selective adsorption of mercury ions because the amide groups can form covalent bonds with mercury ions.
Dynamic simulation of the water quality in rivers based on the IWA RWQM1. Application of the new simulator CalHidra 2.0 to the Tajo River
Authors: Martín C. , Cardona C.M. , San Martín D. , Salterain A. , Ayesa E.
Published: September 2006

This paper presents a new model for the dynamic prediction of water quality in rivers using in-series continuously stirred tank reactors (CSTR) and process transformations based on the IWA RWQM1. The transport model introduces a new parameter f (fraction of solids that are not retained in the in-series reactors) that splits hydraulic and solids retention times, regulating the transport of particulate substances along the river stretch. The characterization of the model components is based on elemental mass fractions, and closed mass balance is guaranteed for each process transformation. The resulting model has been implemented in the new simulator CalHidra 2.0 and applied to a branch of the Tajo River in the Madrid area. The spatial profiles of ammonium, nitrates, and dissolved oxygen in different seasonal periods have been used to calibrate the model. The proposed model also has shown its usefulness for exploring the evolution of the water quality in the Tajo River under different scenarios.
First flush and natural aggregation of particles in highway runoff
Authors: Li Y. , Lau S.-L. , Kayhanian M. , Stenstrom M.K.
Published: September 2006

Particle Size Distribution (PSD) in highway runoff was monitored in the 2004–2005 rainy season at three highway sites in west Los Angeles, California. PSD was measured for 200 grab samples for 18 storm events. Particles and especially larger particles showed a strong first flush. On average, the initial 20% runoff volume transported approximately 28% total number of particles between 0.5 and 2 μm in diameter, more than 30% of particles between 2 and 30 μm and more than 40% of particles larger than 30 μm. A naturally occurring aggregation was observed with smaller particles and mixing experiments were performed to determine the possible benefits for sedimentation and filtration. Samples composited from grab samples manually collected over the first hour of runoff were gently mixed (G = 38) and small particle concentration decreased by more than 50%. After 24 hours the number of particles with diameter between 0.5 and 7 μm decreased by 51% with gentle mixing and the same size particles decreased by only 14% without mixing. Number of particles with diameter larger than 20 μm increased by 6 and 4.5 times with and without mixing, respectively. Slow mixing can improve sedimentation efficiency by more than 40% for particles less than 20 μm in diameter.