bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxic effect of serial perfluorosulfonic and perfluorocarboxylic acids on the membrane system of a freshwater alga measured by flow cytometry
Authors: Liu Wei , Chen Shuo , Quan Xie , Jin Yi-He
Published: June 2008

Flow cytometric measurements were used to investigate the toxic effect of perfluorobutanoic sulfonate (PFBS), perfluorooctane sulfonate (PFOS), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorododecanoic acid (PFDoA), and perfluorotetradecanoic acid (PFTeA) on some membrane systems of the freshwater alga species Scenedesmus obliquus. Among the test compounds, PFOS, PFDoA, and PFTeA inhibited algal growth rate in a concentration-dependent manner while PFBS, PFHxA, and PFOA did not inhibit algal growth within the test concentration ranges. An enhancement of the mitochondrial membrane potential (MMP) and cell membrane permeability in S. obliquus was observed caused by exposure to PFOS, PFOA, PFDoA, and PFTeA. Both carbon chain length and acid group influenced the toxicity of PFAAs, where the toxicity increased with increasing carbon chain length for the compounds belonging to the same class. The observed effective concentrations lie in the micromole range and the test compounds disrupted membrane properties at concentrations below those associated with algal growth inhibition. Flow cytometry is proved to be a useful technique for toxicity testing with microalgae and provide additional information regarding the mode of action of PFAAs to algal species.
A review of independent action compared to concentration addition as reference models for mixtures of compounds with different molecular target sites
Authors: Cedergreen Nina , Christensen Anne M , Kamper Anja , Kudsk Per , Mathiassen Solvejg K , Streibig Jens C , Sørensen Helle
Published: June 2008

From a theoretical point of view, it has often been argued that the model of independent action (IA) is the most correct reference model to use for predicting the joint effect of mixtures of chemicals with different molecular target sites. The theory of IA, however, relies on a number of assumptions that are rarely fulfilled in practice. It has even been argued that, theoretically, the concentration addition (CA) model could be just as correct. In the present study, we tested the accuracy of both IA and CA in describing binary dose-response surfaces of chemicals with different molecular targets using statistical software. We compared the two models to determine which best describes data for 158 data sets. The data sets represented 98 different mixtures of, primarily, pesticides and pharmaceuticals tested on one or several of seven test systems containing one of the following: Vibrio fischeri, activated sludge microorganisms, Daphnia magna, Pseudokirchneriella subcapitata, Lemna minor, Tripleurospermum inodorum, or Stellaria media. The analyses showed that approximately 20% of the mixtures were adequately predicted only by IA, 10% were adequately predicted only by CA, and both models could predict the outcome of another 20% of the experiment. Half of the experiments could not be correctly described with either of the two models. When quantifying the maximal difference between modeled synergy or antagonism and the reference model predictions at a 50% effect concentration, neither of the models proved significantly better than the other. Thus, neither model can be selected over the other on the basis of accuracy alone.
Examining the single and interactive effects of three insecticides on amphibian metamorphosis
Authors: Boone Michelle D
Published: June 2008

Although aquatic communities frequently are exposed to a number of pesticides, the effects of chemical mixtures are not well understood. In two separate studies, I examined how insecticide mixtures influenced the likelihood of unpredictable, nonadditive effects on American toad (Bufo americanus) and green frog (Rana clamitans) tadpoles reared in outdoor aquatic communities. I exposed tadpoles to single or multiple insecticides at approximately half the reported median lethal concentrations using insecticides that were either acetylcholinesterase inhibitors (carbaryl or malathion) or a sodium-channel disruptor (permethrin). I found that combinations of insecticides with the same mode of action were more likely to have nonadditive effects on amphibian metamorphosis compared with those having different modes of action. Additionally, in one study, a commercial formulation of permethrin led to near-complete elimination of American toads, suggesting that this formulation could have adverse effects on aquatic communities. Many community studies exploring the ecological effects of expected environmental concentrations of pesticides have suggested that indirect effects in the food web, rather than direct effects on individual physiology, have the largest effect on amphibians. The present study indicates that direct effects of pesticides may become particularly important when insecticides with the same mode of action are present in the environment.
Hormesis: Why it is important to toxicology and toxicologists
Authors: Calabrese Edward J
Published: June 2008

This article provides a comprehensive review of hormesis, a dose-response concept that is characterized by a low-dose stimulation and a high-dose inhibition. The article traces the historical foundations of hormesis, its quantitative features and mechanistic foundations, and its risk assessment implications. The article indicates that the hormetic dose response is the most fundamental dose response, significantly outcompeting other leading dose-response models in large-scale, head-to-head evaluations. The hormetic dose response is highly generalizable, being independent of biological model, endpoint measured, chemical class, and interindividual variability. Hormesis also provides a framework for the study and assessment of chemical mixtures, incorporating the concept of additivity and synergism. Because the hormetic biphasic dose response represents a general pattern of biological responsiveness, it is expected that it will become progressively more significant within toxicological evaluation and risk assessment practices as well as have numerous biomedical applications.
The influences of ambient and body calcium on cadmium and zinc accumulation in Daphnia magna
Authors: Tan Qiao-Guo , Wang Wen-Xiong
Published: June 2008

The dissolved uptake rate constant (ku), dietary assimilation efficiency (AE), and efflux rate constant (ke) of cadmium (Cd) and zinc (Zn) were quantified in a freshwater zooplankton Daphnia magna cultured at different ambient calcium (Ca) concentrations. The animals were first acclimated to different ambient Ca levels for 7 d from birth before the biokinetic measurements at corresponding Ca levels. With increasing ambient Ca level from 0.5 to 200 mg/L, the body Ca content increased from 0.91% (as tissue dry wt) to 3.75%. The ku for Cd decreased by nine times; for Zn it decreased by 2.6 times; and the AE decreased from 62 to 19% and from 46 to 24% for Cd and Zn, respectively. In contrast, Ca levels did not affect significantly the efflux rates of Cd and Zn. The effects of ambient and body Ca levels were separated by measuring the biokinetic parameters in both low- (0.5 mg/L) and high- (50 mg/L) Ca environments using the daphnids containing different body Ca levels. Ambient and body Ca levels had synergistic inhibitory effects on the AEs of Cd and Zn; however, the protective effects against dissolved uptake of Cd and Zn were explained fully by the effects of ambient Ca. The body Ca either had no significant effect (for Cd) or stimulative effects (for Zn). Multiphase biokinetic modeling using the measured parameters gave reasonable predictions of the body burdens of Cd and Zn in different Ca environments. Our results better explain the role of ambient and body Ca in the accumulation of Cd and Zn in D. magna.
Effective Open Hole Horizontal Completion System for Multistage Fracturing and Stimulation
Authors: Seale R. , Athans J.
Published: June 2008

This paper describes an efficient multistage horizontal openhole (OH) completion technique as an alternative to conventional openhole or cemented and perforated lateral completions. The application focuses on OH completions in the Edwards Lime of South Texas. Horizontal wells have been drilled extensively in this deep high temperature gas field. This paper will detail the new horizontal completion system run as part of the production liner, which does not require cementing and provides mechanical diversion at specified intervals, so fracturing and stimulations can be pumped effectively to their targeted zone. Details of the engineering design and testing will be specified, with extensive elaboration on the applications and case histories were these systems have been successfully deployed. The case histories will detail the operational efficiencies of the system in conjunction with the enhanced production realized.
Hydrajet Perforating and Proppant Plug Diversion in Multi-Interval Horizontal Well Fracture Stimulation: Case Histories
Authors: East Loyd E. , Bailey Michael , McDaniel B. W.
Published: June 2008

This case history paper presents fracture stimulation using coiled tubing (CT) hydrajetting, followed by (1) annular-path pumping of the fracturing treatment and (2) use of high-concentration proppant slugs to create proppant plugs for diversion. The process of hydrajet perforating and annular-path pumping (HPAP) has been used effectively for vertical well completions and is especially applicable for multi-interval completions. Further, use of this process for multi-interval fracturing of horizontal well completions has been performed successfully in several North America reservoirs, and in Texas at depths below 15,700 ft true vertical depth (TVD) and measured depths (MD) of more than 16,700 ft.

Cased and cemented horizontal completions present several challenges for the HPAP method, including (1) unique CT calculations and operating procedures, and (2) proppant plug-setting procedures. This multi-stage completion process can also be applied in other methods of horizontal completions that incorporate a solid liner.

Several case histories are examined to (1) highlight lessons learned in performance of this method on horizontal well completions, and (2) demonstrate efficiencies gained as compared to following conventional practices.
Improved Single-Trip Multistage Completion Systems for Unconventional Gas Formations
Authors: Durst Doug G. , Travis Harris , Contreras Jesus D. , Watson Don R.
Published: June 2008

Cost-effective development of unconventional gas resources depends upon strategic application of advancing technologies. By employing efficient fracturing techniques with an appropriate multi-stage fracturing completion, operators can achieve higher initial gas rates, increased recovery rates and reduced completion costs. The completion process employs a single-trip multi-stage isolation completion system which is driving the cost-effective exploitation of difficult reservoirs. Operational issues, case studies and system improvements, such as the means to isolate water producing zones, will be covered.

Key factors to be reviewed include reserve estimates, selection of number of fractures, production behavior analysis, production forecast analysis, risk analysis, fracture design, and economic evaluation.

Installation strategy issues will be addressed regarding equipment and operations such as quantity and spacing of packers and sleeves as well as the fracturing process. These strategies are critical relative to achieving mechanical, volumetric and economic success which is established by the efficiency of each fracture and total gas production rate when compared to initial evaluations.

The one-trip multi-stage isolation fracturing completion process reduces rig time and cost for hydraulic fracturing services, accelerates production and improves reservoir drainage. When coupled with effective fracturing strategies and best practice procedures, the system provides improved production from unconventional gas formations.
Observations From Tight Gas Reservoir Stimulations in the Rocky Mountain Region
Authors: Borchardt Erik , Cavens Jessica , Wieland Craig , Pluemer Brian , Graham Don , Erwemi Abdunnaser , Kazantsev Aleksey , Calvez Joel Le
Published: June 2008

Introduction

Unconventional tight gas reservoirs are made economical through effective stimulation techniques. Hydraulic fracture mapping combined with an in-depth knowledge of reservoir geology and geomechanics can give a better understanding to the effectiveness of reservoir stimulation. Massive hydraulic fractures from two wells in the Rocky Mountain region were mapped in real time with a 3-D stimulation viewer software package. One well employed techniques standard to the area –while some experimental fracture techniques were tested on the other. A general east-west orientation of planar fracture geometry was found with a maximum fracture event length of 800 feet. The planer fracturing scheme is consistent with low amounts of acoustic anisotropy recorded. Increasing treating and bottom hole pressures with time observed in this study indicate fracture length growth for each stage. 11 and 12 stages were chosen for the two well completion program based on data from an open hole logging and geomechanics.

Some experimental fracturing techniques were tested including longer pump times, larger sand volumes, high viscosity fracture fluids, re-fracturing for re-orientation, using temporary, degradable fiber plugs between stages, and plugging of stages with ball sealers. Perforation entry by stage was effective and some stages could possibly be eliminated to save cost. There is not a direct correlation between pump time, sand volume, and stage height. Ball sealers were not an optimum method for closing off a stage for fracturing, but there is evidence that degradable fiber plugs could be a cost saving option between stages. This paper outlines in more detail the observations from hydraulic fracture mapping in this area.

Regional Background

This area of study includes 3000 vertical feet of fluvial and marine sands located in the Rocky Mountain region of the United States. (Figure 1) The formation contains natural fractures, laterally restricted lenticular sandstones, and tight brittle sands. The main natural gas reservoir interval is from 5000 to 8500 feet. The productive sands have an average porosity of about 7% and permeability is in the micro-Darcy range. The first well was drilled in this region of the Rocky Mountains in 1955. In the late 1990's the discovery of increased production by fracturing lenticular sands has made this a profitable area. Due to the nature of these tight sands – wells can be located in closer proximity without lowering the production rates of neighboring wells. Wells are currently drilled on 10 acre density. Much of the area uses directional drilling from pad wells to reduce surface damage.
Enhancement of food waste digestion in the hybrid anaerobic solid-liquid system
Authors: Liu X. Y. , Ding H. B. , Sreeramachandran S. , Stabnikova O. , Wang J. Y.
Published: June 2008

The hybrid anaerobic solid-liquid (HASL) system is a modified two-phase anaerobic digester for food waste treatment. To enhance the performance of anaerobic digestion in the HASL system, thermal pre-treatment (heating at 150°C for 1 h) and freezing/thawing (freezing for 24 h at−20°C and then thawing for 12 h at 25°C) were proposed for food waste pre-treatment before the anaerobic digestion. Both processes were able to alter the characteristics and structure of food waste favoring substance solubilization, and hence production of methane. However, there was no net energy gain when the energy required by the pre-treatment processes was taken into account.
Analysing sludge balance in activated sludge systems with a novel mass transport model
Authors: Patziger M. , Kainz H. , Hunze M. , Józsa J.
Published: June 2008

In activated sludge systems the mechanically treated wastewater is biologically cleaned by biomass (activated sludge). The basic requirement of an efficient biological wastewater treatment is to have as a high biomass concentration in the biological reactor (BR) as possible. The activated sludge balance in activated sludge systems is controlled by the settling, thickening, scraper mechanism in the secondary settling tank (SST) and sludge returning. These processes aim at keeping maximum sludge mass in the BR and minimum sludge mass in the SST even in peak flow events (storm water flow). It can be, however, only reached by a high SST performance. The main physical processes and boundary conditions such as inhomogeneous turbulent flow, geometrical features of the SST, wastewater treatment plant (WWTP) load, return sludge flow, sludge volume index etc. all influence settling thickening and sludge returning. In the paper a novel mass transport model of an activated sludge system is presented which involves a 2-dimensional SST model coupled with a mixed reactor model of the biological reactor. It makes possible to investigate different sludge returning strategies and their influence on the sludge balance of the investigated activated sludge system, furthermore, the processes determining the flow and concentration patterns in the SST. The paper gives an overview on the first promising model results of a prevailing peak flow event investigation at the WWTP of Graz.
Nutrient removal process selection for planning and design of large wastewater treatment plant upgrade needs
Authors: Urgun-Demirtas M. , Pagilla K. R. , Kunetz T. E. , Sobanski J. P. , Law K. P.
Published: June 2008

A protocol to select nutrient removal technologies that can achieve low nutrient effluents (total nitrogen (TN) < 5 mg/L and total phosphorus (TP) < 0.5 mg/L) was developed for different wastewater treatment plant (WWTP) sizes based on the research conducted during a Water Environment Research Foundation funded project. The adaptable protocol includes technology and cost assessment of feasible (pre-screened) nutrient removal technologies that are being successfully implemented at full scale. The information collected from the full scale nutrient removal plants to develop this protocol includes design, operational, performance, and cost data through a direct survey of plants, and published data. The protocol includes a “technology threshold” approach consisting of Tier I (TN < 5.0 mg/L; TP < 0.5 mg/L) and Tier II (TN < 3.0 mg/L; TP < 0.1 mg/L) effluent nutrient levels for different plant sizes. A very large WWTP (1,250,000 m3/day flow) in Chicago, Illinois, USA adapted this protocol for master planning and design of future nutrient removal facilities based on plant and site specific criteria.
Developing a framework for continuous use of models in daily management and operation of WWTPs: a life cycle approach
Authors: Sin Gürkan , De Pauw Dirk J. W. , Weijers Stefan , Vanrolleghem Peter A.
Published: June 2008

We developed and evaluated a framework for the continuous use of dynamic models in daily management and operation of WWTPs. The overall aim is to generate knowledge and build in-house capacity for the reliable use of dynamic models in practice (within a regional water authority in The Netherlands). To this end, we have adopted a life cycle approach, where the plant model follows the different stages that make up the typical lifespan of a plant. Since this approach creates a framework in which models are continuously reused, it is more efficient in terms of resources and investment than the traditional approach where one always makes a new model for the plant whenever it is needed. The methodology was evaluated successfully at a 50,000 PE domestic EBPR plant (Haaren, The Netherlands). It is shown that the continuous use and update of models in a cyclic manner creates a learning cycle, which results in experience and knowledge generation about the plant's modelling that accumulates and translates into improvements into the modelling quality and efficiency. Moreover, a model is now always on-the-shelf for process optimization.
Upgrading of wastewater treatment plants for nutrient removal under optimal use of existing structures
Authors: Winkler S. , Gasser M. , Schättle W. , Kremmel D. , Kletzmayr P. , Matsché N.
Published: June 2008

Upgrading of wastewater treatment plants under maximum use of existing structures is often an important requirement, but also useful due to a number of aspects. Because of a change in legal effluent requirements, a number of plants in Austria, typically aged 20+ years, were required to be extended. The two stage activated sludge HYBRID®-process often provides an interesting design alternative for such plant upgrades, especially in case an anaerobic sludge treatment stage already exists. It provides high nutrient removal capacity at low area demand. The latter is especially important in cases where no or very limited extension area is available making it the key factor to preserve a site for future use. Based on two full stage case studies the adaptation of the plant layout, first operation results and a synthetic cost comparison to a conventional (single stage) plant extension are given.
Utilising laboratory experiments as a first step to introduce primary sludge hydrolysis in full-scale
Authors: Jönsson K. , Pottier A. , Dimitrova I. , Nyberg U.
Published: June 2008

Laboratory experiments have been utilised as a tool to determine the possible yield of soluble COD and VFAs from settled influent and preprecipitated sludge at Klagshamn wastewater treatment plant and to determine the degradability of the organic matter. The release of ammonium and orthophosphate from the hydrolysed sludge has been estimated. It is possible to produce soluble organic matter of good quality from settled influent and preprecipitated sludge at Klagshamn WWTP. Denitrification rates of 3.1 mg NO3-N/(g VSS × h) were found for the hydrolysate in laboratory tests. Owing to the low phosphate concentrations in the hydrolysate from preprecipitated sludge, it shows a potential for postdenitrification despite stringent phosphorus outlet demands. Calculations based on data gained from the laboratory experiments show that about 50% of the external carbon source used today can be saved with minor changes in the plant operation except that the hydrolysis has to be established. Based on these findings, full-scale experiments with internal hydrolysis in the primary clarifiers were scheduled in one of the two lines at Klagshamn WWTP for the summer of 2007.
Generation of diurnal variation for influent data for dynamic simulation
Authors: Langergraber G. , Alex J. , Weissenbacher N. , Woerner D. , Ahnert M. , Frehmann T. , Halft N. , Hobus I. , Plattes M. , Spering V. , Winkler S.
Published: June 2008

When using dynamic simulation for fine tuning of the design of activated sludge (AS) plants diurnal variations of influent data are required. For this application usually only data from the design process and no measured data are available. In this paper a simple method to generate diurnal variations of wastewater flow and concentrations is described. The aim is to generate realistic influent data in terms of flow, concentrations and TKN/COD ratios and not to predict the influent of the AS plant in detail. The work has been prepared within the framework of HSG-Sim (Hochschulgruppe Simulation, E-mail: http://www.hsgsim.org), a group of researchers from Germany, Austria, Luxembourg, Poland, the Netherlands and Switzerland.
The main wastewater treatment plant of Vienna: favourable operation conditions as a consequence of well designed tender procedures
Authors: Partaj T. , Papp M. , Weiss J.
Published: June 2008

In the planning phase of the extension of the Main Treatment Plant of Vienna, special effort and emphasis were put on the conception of the tender procedure. The project tender was divided into several tender units in order to achieve optimum quality standards by specialised workmanship. Important parameters for operation conditions, especially energy consumption and maintenance costs, were considered and valuated according to the tender guidelines. Suppliers were required to prove the guaranteed quality standards of the tender documents by means of preliminary installation units and extensive performance check procedures. Only after fulfilment of all requirements were suppliers allowed to apply the design of the preliminary installation works to the entire installation. If necessary, extensive optimization works were carried out. Thus favourable operation conditions were achieved and, in particular, a highly efficient aeration system was implemented.

Process parameters were optimized by means of a follow-up project during the regular operation phase, taking into consideration the results of the performance check procedures. Further optimization of energy consumption was thereby achieved.
Water Renew systems: wastewater polishing using renewable energy crops
Authors: Sugiura A. , Tyrrel S. F. , Seymour I. , Burgess P. J.
Published: June 2008

Macronutrients concentrations were measured during the establishment year of short rotation coppice of Salix viminalis, Populus trichocarpa, Eucalyptus gunnii irrigated with secondary treated effluent. Twenty four plots of 12.25 m2 located in Cranfield, Bedfordshire, UK on heavy fine clay were drip-irrigated in order to maintain their soil moisture at field capacity. Soil water was sampled at 30 cm and 60 cm with soil water suction cup samplers fortnightly. Willow and eucalyptus received more than 900 mm of effluent corresponding to more than 290 kg-N/ha, 30 kg-P/ha and 220 kg-K/ha. Poplar and unplanted plots received less than 190 kg-N/ha, 17 kg-P/ha and 120 kg-K/ha. For soil water nitrogen concentrations as for potassium concentrations, there was an irrigation effect only on eucalyptus planted plots. On all plots, there was no significant effect of tree presence or species. There was no phosphorus measurable in soil water samples. Groundwater chemistry was unaffected by irrigation. Thus, intensive irrigation of short rotation coppice during the establishment year should not be considered as a major threat to groundwater quality. Willows and eucalyptus can absorb almost a third more effluent than poplar and unplanted plots without having any significant effect on soil water chemistry.
The effect of reclaimed wastewater on the quality and growth of grapevines
Authors: Mendoza-Espinosa L. G. , Cabello-Pasini A. , Macias-Carranza V. , Daessle-Heuser W. , Orozco-Borbón M. V. , Quintanilla-Montoya A. L.
Published: June 2008

The effect of the use of treated wastewater on the growth of cabernet sauvignon and merlot grapes from the Guadalupe Valley, Mexico was evaluated. Secondary advanced effluent was used to irrigate the grapevines at a rate of 66 L/vine/week. Wastewater quality results confirmed that all parameters complied with Mexican legislation for crop irrigation as well as reuse in activities in which the public would be in direct or indirect contact with the reclaimed water. Results showed that the number of leaves per shoot and the overall biomass increased in plants irrigated with wastewater and grape production per plant was 20% higher. The concentration of carbohydrates, organic acids and pH were similar in grapes from vines irrigated with wastewater to those irrigated with groundwater. Throughout the experiment, no fecal coliform bacteria were detected in the cultivated grapes. The wastewater caused an increase in the biomass of the grapevines and there was no presence of microbial indicators in the final product so a higher wine production could be achieved without an increase in health risk related problems. If 200 L/s of reclaimed wastewater would be returned to be used for grapevine irrigation in Valle de Guadalupe (the same amount that is currently being sent as drinking water to Ensenada), assuming an irrigation application of 6,000–7.500 m3/ha/year, approximately 837–1046 hectares (ha) of grapevines could be irrigated. Part of ongoing research includes an economical analysis of the best options for Ensenada and the Valle de Guadalupe in order to establish the optimum volume of water to be returned, the cost of its transportation, as well as the cost of irrigation.
Membrane technology for sustainable treated wastewater reuse: agricultural, environmental and hydrological considerations
Authors: Oron Gideon , Gillerman Leonid , Bick Amos , Manor Yossi , Buriakovsky Nisan , Hagin Joseph
Published: June 2008

Field experiments were conducted in agricultural fields in which secondary wastewater of the City of Arad (Israel) is reused for irrigation. For sustainable agricultural production and safe groundwater recharge the secondary effluent is further polished by a combined two-stage membrane pilot system. The pilot membrane system consists of two main in row stages: Ultrafiltration (UF) and Reverse Osmosis (RO). The UF stage is efficient in the removal of the pathogens and suspended organic matter while the successive RO stage provides safe removal of the dissolved solids (salinity). Effluents of various qualities were applied for agricultural irrigation along with continuous monitoring of the membrane system performance. Best agricultural yields were obtained when applying effluent having minimal content of dissolved solids (after the RO stage) as compared with secondary effluent without any further treatment and extended storage. In regions with shallow groundwater reduced soil salinity in the upper productive layers, maintained by extra membrane treatment, will guarantee minimal dissolved solids migration to the aquifers and minimize salinisation processes.
Phosphorus release from agriculture to surface waters: past, present and future in China
Authors: Chen M. , Chen J.
Published: June 2008

So far, there is no clear picture at national level regarding the severity, spatial distribution, trend and driving forces of phosphorus (P) release from agriculture to surface waters in China, which presents a major obstacle for surface water quality management and relevant policy-making. By applying a proposed Activity-Unit-Balance (AUB) methodology, this paper retrospects and prospects phosphorus release from agricultural activities to surface waters from1978 to 2050 in China. Modelling results reveal that P load from agriculture has increased 3.4 times during 1978–2005 and will increase by 1.8 times during 2005–2050. Although major contribution factors are mineral fertiliser application (MFA) and livestock feeding activities (LFAs), LFAs will be the single largest source of increased total P load in the next decades. Most importantly, agricultural pollution in China is spatially overlapped with industrial and domestic pollution, and regions in the southeast to “Heihe-Tengchong” line have to be confronted with an austere challenge to control and manage industrial and domestic pollution as well as pollution from agriculture at present and in future.
Comparison of pollutant loading estimation using different land uses and stormwater characteristics in Ballona Creek Watershed
Authors: Park Mi-Hyun , Stenstrom Michael K.
Published: June 2008

Estimation of stormwater pollutant loads using land use based models has been widely used for establishing regulations and management practices. This approach requires land use information to assign the imperviousness or runoff coefficients (RC) and event mean concentrations (EMCs) for the pollutants of interest. This simplistic approach is useful to estimate the total mass emissions. However, different research groups have used various parameters based upon similar data sources, and there are very few validations using actual field data. This study compares the assumptions, methodologies and results of several, independent modelling efforts, and functions as a quality and sensitivity study of the methodologies. The similarity or differences of the various model results serve as a qualitative indicator of the state of art for this type of stormwater modelling.
Assessing urban stormwater toxicity: methodology evolution from point observations to longitudinal profiling
Authors: Grapentine Lee , Rochfort Quintin , Marsalek Jiri
Published: June 2008

The quality of aquatic habitat in a stormwater management facility located in Toronto, Ontario, was assessed by examining ecotoxicological responses of benthic invertebrates exposed to sediment and water from this system. Besides residential stormwater, the facility receives highway runoff contaminated with trace metals, polycyclic aromatic hydrocarbons (PAHs), and road salt. The combined flow passes through two extended detention ponds (in series) and a vegetated outlet channel. Toxicity of surficial sediment collected from 14 longitudinally arrayed locations was assessed based on 10 acute and chronic endpoints from laboratory tests with four benthic organisms. Greatest overall toxicity was observed in sediment from sites in the upstream pond, where mortality to amphipods and mayflies reached up to 100%. Downstream pond sediment was less toxic on average than the upstream pond sediment, but not the outlet channel sediment where untreated stormwater discharges provided additional sources of contamination. Macroinvertebrate communities in sediment cores were depauperate and dominated by oligochaetes and chironomids, with minimum densities and diversity at the deeper central pond sites. While sediment toxicity was associated with high concentrations of trace metals and high-molecular weight PAHs, benthic community impoverishment appeared related to high water column salinity.
A cost comparison of traditional drainage and SUDS in Scotland
Authors: Duffy A. , Jefferies C. , Waddell G. , Shanks G. , Blackwood D. , Watkins A.
Published: June 2008

The Dunfermline Eastern Expansion (DEX) is a 350 ha mixed development which commenced in 1996. Downstream water quality and flooding issues necessitated a holistic approach to drainage planning and the site has become a European showcase for the application of Sustainable Urban Drainage Systems (SUDS). However, there is minimal data available regarding the real costs of operating and maintaining SUDS to ensure they continue to perform as per their design function. This remains one of the primary barriers to the uptake and adoption of SUDS. This paper reports on what is understood to be the only study in the UK where actual costs of constructing and maintaining SUDS have been compared to an equivalent traditional drainage solution. To compare SUDS costs with traditional drainage, capital and maintenance costs of underground storage chambers of analogous storage volumes were estimated. A whole life costing methodology was then applied to data gathered. The main objective was to produce a reliable and robust cost comparison between SUDS and traditional drainage.

The cost analysis is supportive of SUDS and indicates that well designed and maintained SUDS are more cost effective to construct, and cost less to maintain than traditional drainage solutions which are unable to meet the environmental requirements of current legislation.
Evaluation of street sweeping effectiveness as a stormwater management practice using statistical power analysis
Authors: Kang Joo-Hyon , Stenstrom Michael K.
Published: June 2008

Although street sweeping is commonly regarded as a cost-effective stormwater best management practice, there is little quantitative evidence that street sweeping directly improves runoff water quality. In this paper, several previous street sweeping studies were re-evaluated using statistical power analysis. Two-group, independent-sample one-sided t-test power analyses were performed using log-transformed event mean concentrations (EMCs) of total suspended solids, suspended sediment concentration or chemical oxygen demand. The effect size between the two groups was estimated using the sweepers' pick-up efficiency, which showed that the failure to detect the difference between mean EMCs of the two sample groups (i.e., unswept and swept groups) is likely due to limited sample numbers. Too few samples, which also resulted in a high coefficient of variation, were analysed to detect the likely difference between swept and unswept observations. In addition, the temporal gap between street sweeping and subsequent storm events was not controlled to improve statistical power.
The reliability of sediment transport predictions in sewers: influence of hydraulic and morphological uncertainties
Authors: Banasiak Robert , Tait Simon
Published: June 2008

The paper is focussed on the concept of defining the “predictability” of sediment transport. Engineers are faced with a number of sediment transport formulas derived from different tests and described as suitable for application in sewers. Bed and suspended load formulas vary in form and performance, generally depending on the data sets that were used to calibrated them. As different sediment types have been tested no single, generally valid formula has been established so far. Formulas are distributed in the scientific literature and are often reported without the information necessary to define their range of potential applicability. Therefore, this paper along with analysing the formulas available, will also comment on the assumptions used in their development as well as the reliability of their underlying data to aid engineers in the selection of the most appropriate sediment transport formulae to correspond with the environment in which they are working.
Estimation of uncertainty in long term combined sewer sediment behaviour predictions, a UK case study
Authors: Schellart A. N. A. , Buijs F. A. , Tait S. J. , Ashley R. M.
Published: June 2008

There are regulatory driven requirements for UK water companies to reduce the number of properties at risk of sewer flooding. One of the potential causes of sewer flooding is the presence of persistent sediment deposits in sewers. This is a common problem in many combined sewers. Although the regulation is risk based, there is a gap in current knowledge on how risk assessment is affected by the uncertainty in sewer solids behaviour prediction. This paper describes a UK case study exploring the possibility of estimating uncertainty in sewer sediment deposit level predictions, using Monte Carlo simulations combined with a response database.
In situ measurements of shear stresses of a flushing wave in a circular sewer using ultrasound
Authors: Staufer P. , Pinnekamp J.
Published: June 2008

Deposits build up in sewer networks during both spells of dry weather and in connection with storm water events. In order to reduce the negative effects of deposit on the environment, different cleaning technologies and strategies are applied to remove the deposits. Jet cleaning represents the most widely used method to clean sewers. Another alternative cleaning procedure is flushing. On account of new developments in measurement and control panels, the flushing method is becoming more important. Therefore, in the last few years a number of new flushing devices have been constructed for application in basins, main sewers and initial reaches. Today, automatic flushing gates are able to accomplish cleaning procedures under economical and ecological conditions.

The properties of flushing waves for cleaning sewers have been determined by several mathematical-numerical studies. These various investigations use altering numerical schemes, are based on different sets of physical equations and take one- or more dimensional aspects into account. Considering that bottom shear stress is the key value to evaluate the beginning of motion of any deposit, one may use this value that has to be determined by measurements. This paper deals with shear stresses caused by flushing waves which have been measured by an ultrasonic device that can determine the velocity in different depths of flow. Thus, it is possible, within certain limits, to calculate bottom shear stresses based on the log-wall law. Further discussion will deal with the requirements of measurements, its uncertainty and aspects in respect to the application of simulation of flushing waves.
The transfer of infiltration measurement results to other sewers by means of discriminant analysis
Authors: Franz Torsten , Krebs Peter
Published: June 2008

The cost-oriented and sustainable operation of sewer systems requires a comprehensive knowledge about the infiltration situation in the catchment. Owing to the high expenditures for infiltration measurements a reliable transfer of measurement results to other sewer sections would be highly beneficial. Assuming a functional relationship between sewer characteristics and infiltration rates can be identified, such a transfer can be realised by means of classification techniques. In this paper a method is introduced which is based on discriminant analysis and which allows for a transfer of measurement results to similar sub-catchments. The method was applied using two data sets with measured or virtual infiltration rates. It yields acceptable results as a total fraction of 50% to 75% of the investigated sub-catchments was assigned correctly. Furthermore, additional information to assess the results was provided. The quality of the transfer results depends strongly on the homogeneity of the considered sub-catchments. Due to this restriction the practical applicability of the method is restricted. Nevertheless, it might be used as a screening procedure for planning of effective detailed infiltration investigations.
Evaluation of uncertainties in settling velocities of particles in urban stormwater runoff
Authors: Torres A. , Bertrand-Krajewski J.-L.
Published: June 2008

Field experiments were carried out to contribute to the assessment of the VICAS protocol aiming to measure settling velocities of particles. Samples of deposited sediments have been taken in the Django Reinhardt stormwater detention and settling tank in Chassieu, France, using sediment traps located on the tank bottom. The first set of experiments was designed to assess the VICAS protocol in terms of mass balance and repeatability. A bias in the measurement of settling velocities distributions of deposited sediments (i.e. particles with high settling velocities) was suspected and confirmed by specific tests. Uncertainties in the final distribution curves have been evaluated by using Monte Carlo simulations and the law of propagation of uncertainties. All uncertainty calculations were implemented in a MatLab code named UVICAS used for each experiment. This code allows analysing the main sources of uncertainties and their evolution during experiments. Uncertainties in the final distribution curves decrease with increasing values of settling velocities and are lower than 1%.
Low Frequency of Epstein Barr Virus Association and High Frequency of p53 Overexpression in an Argentinean Pediatric T-Cell Lymphoma Series
Authors: Chabay Paola , De Matteo Elena , Lorenzetti Mario , Barón Anahí Vijnovich , Valva Pamela , Preciado María Victoria
Published: June 2008

T-cell non–Hodgkin's lymphomas (NHLs) represent 10% to 15% of all diagnosed lymphomas in Western countries. Various geographic frequencies of T-cell NHL have been documented, in part reflecting increased exposure to pathogenic factors such as Epstein-Barr virus (EBV). Our aims were to assess EBV and p53 expression in Argentine pediatric T-cell lymphoma and to correlate them with patients' survival. Epstein-Barr encoded RNAs (EBERs) in situ hybridization and LMP1 and p53 immunohistochemical staining were performed on formalin-fixed paraffin-embedded lymph node biopsies from 25 pediatric T-lymphoma patients. In 17 of 25 samples good-quality DNA was obtained, and EBER polymerase chain reaction was assessed to confirm in situ hybridization and immunohistochemical results. Epstein-Barr virus expression was found in 8.0% of cases. p53-positive staining was distributed in 92% of pediatric cases. Kaplan-Meier survival analysis showed that neither EBV nor p53 expression was statistically significantly associated with event-free survival. Our data showed a low frequency of EBV association with pediatric T-cell lymphoma. It seems that p53 plays an important role in proliferation in our studied population, since it is overexpressed in 92% of T-cell lymphoma cases.
Application of Lippmann interference photography to data storage
Authors: Contreras Kevin , Pauliat Gilles , Arnaud Carole , Roosen Gérald
Published: June 2008

Lippmann’s interference photography is an elegant process to record coloured images in the volume of a sensitive material. We propose to use this technique for wavelength multiplexed data storage in a page-oriented approach. Using computer simulations, we demonstrate that the capacities reached with this technique are similar to those reached by volume holographic data storage.
Electrically induced Bragg Reflectors in InP/InGaAsP waveguides as ultrafast optoelectronic modulators
Authors: De Laurentis Martina , Irace Andrea , Breglio Giovanni
Published: June 2008

In this paper, with the help of numerical simulations, we show how it is possible to create a Distributed Bragg Reflector by electrically inducing periodical refractive index variations in unperturbed III-V rib-waveguides to design different kind of devices. This approach allows to induce the optoelectronic devices by a suitable reconfiguration of the potential applied to the electrode matrix, i.e. to have a defined routing/switching matrix, or, for dynamic applications, realize intensity modulators, capable of reaching a theoretical 40 GHz switching speed.
TOWARDS NON-DISCRIMINATION AGAINSTWOMEN AND DE JURE EQUALITY IN UGANDA: THE ROLE OF UGANDA'S CONSTITUTIONAL COURT
Authors: SSENYONJO MANISULI
Published: June 2008

The principles of equality and non-discrimination represent the twin pillars or the cornerstone upon which the whole edifice of human rights law is established.1 At least every State in the world today is a party to a human rights treaty prohibiting discrimination on the basis of sex and/or protecting equality between men and women.2 Despite this fact inequality and discrimination remain two major impediments to the enjoyment of human rights of women. Discrimination against women on the basis of sex denies or limits as it does their equality with men, and is ‘fundamentally unjust’ since it violates the principles of equality of rights and respect for human dignity.3 It is an obstacle to the participation of women, on equal terms with men, in the political, social, economic and cultural life of their States, hampers the growth of the prosperity of society and the family and makes more difficult the full development of the potentialities of women.4 International human rights instruments such as Article 3 of the International Covenant on Civil and Political Rights (ICCPR)5 and Article 3 of the International Covenant on Economic, Social and Cultural Rights (ICESCR)6 underline commitment to sexual equality in the enjoyment of all civil and political rights, as well as economic, social and cultural rights. Similarly, Article 2 and 3 of the African Charter on Human and Peoples’ Rights (ACHPR) prohibit discrimination and protect equality before the law.7 This demands de jure (or formal) equality and de facto (or substantive) equality for men and women.8 Formal equality assumes that equality is achieved if a law or policy treats men and women in a neutral manner.9 Substantive equality is concerned, in addition, with the effects of laws, policies and practices and with ensuring that they do not maintain, but rather alleviate, the inherent disadvantages that particular groups experience.10
THE RIGHT TO FREEDOM OF RELIGION AND THE SEARCH FOR JUSTICE THROUGH THE OCCULT AND PARANORMAL IN NIGERIA
Authors: NWAUCHE E. S.
Published: June 2008

The widespread belief1 in the occult and paranormal in Nigeria in the context of the freedom of thought conscience and religion guaranteed by section 38 of the 1999 Constitution of the Federal Republic of Nigeria is the basis of this article which examines the search for justice through the occult and paranormal. By the paranormal which is used interchangeably with supernatural I mean phenomena which cannot be explained by science and reason. To some people “occult” does mean the same thing as paranormal. However for many others “occult” refers to paranormal phenomena which is evil and destructive and includes practices such as witchcraft2