bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen removal from reclaimed water applied to constructed and natural wetland microcosms
Authors: Gale P.M. , Redely K.R. , Graetz D.A.
Published: February 2012

ABSTRACT:  A series of constructed and natural wetlands are currently being used by Orange County, Florida to polish reclaimed municipal wastewater. The system consists of constructed wetlands with low organic matter sandy soils, alternating with natural wetlands with organic soils. The hydrologic flow pattern is through constructed wetland → natural wetland → constructed wetland → natural wetland. Nitrogen removal potential of these wetlands was measured in (1) soil microcosms of each wetland batch fed with reclaimed water at a hydraulic retention time (HRT) of 21 days (experiment I), and (2) soil microcosms of each wetland sequentially batch fed for an HRT of 5 days per wetland for a total HRT of 20 days for the system (experiment II). The experiments were conducted in a greenhouse maintained at 18–32°C. Floodwater nitrogen removal, expressed as first‐order rate constants, ranged from 0.086 (±0.030) to 0.214 (±0.020) days−1 for the wetland soils studied. Nitrogen removal was more rapid in wetlands with mineral soils than organic soils. Based on these rates, 50% of the inorganic nitrogen loaded to these wetlands would be removed at an HRT of 3–8 days. The firstorder rate constants obtained from experiment I were used to predict the floodwater nitrogen removal in experiment II (sequentially batch fed system) and nitrogen removal at the field site. At ambient nitrogen addition levels, the agreement between predicted and measured values was highly significant (slope = 0.98, R2 = 0.98). The overall nitrogen removal efficiency was in the range of 83–89% in the wetlands evaluated. Nitrification and denitrification appear to be major nitrogen removal mechanisms in the wetlands.
Assessment of design and operating parameters for high rate anaerobic dechlorination of segregated kraft mill bleach plant effluents
Authors: Parker Wayne J. , Hall Eric R. , Farquhar Grahame J.
Published: February 2012

ABSTRACT:  The removal of organochlorine from segregated kraft mill bleach plant wastewaters using high rate anaerobic reactors was investigated at bench scale. Modified sludge blanket reactors with long solids retention times were utilized in the study and the adsorbable organic halogen (AOX) technique was used as a measure of wastewater organochlorine content. The factors investigated for influence on dechlorination included the presence or absence of synthetic evaporator condensate as a cosubstrate, hydraulic retention time, and wastewater dilution. Removal efficiencies of AOX ranging from 27 to 65% were observed over hydraulic retention times ranging from 3 to 48 hours. Although bleach plant wastewaters have been reported to be extremely inhibitory to methanogens, methane production was observed under all conditions imposed on the biomass in this study. Approximately 3% of the influent AOX remained in the treated effluent as nonfilterable AOX. Accumulation of AOX in the reactor contents was found to account for 5% of the cumulatives influent AOX.
Comparison of free and total chlorine measurement methods in municipal wastewaters
Authors: Derrigan James , Lin Li‐Yin , Jensen James N.
Published: February 2012

ABSTRACT:  Accurate and precise determination of chlorine residuals is essential for the assessment of disinfection efficiency. In this study, various methods for the analysis of free available chlorine (FAC) and total residual chlorine (TRC) were compared in chlorinated municipal wastewaters. Rates of interferences in the measurements also were determined. The amperometric titration and iodometric II methods were the most reproducible and the iodometric I and potentiometric electrode methods were the least reproducible for the measurement of TRC. The rate of interference in the measurement of FAC by the N,N‐diethyl‐p‐phenylenediamine method was similar to the rate of interference from inorganic monochloramine. The interference rates in the measurement of TRC were in the range of calculated interference rates from organic dichloramines.
Analysis of 10 years of virus monitoring data from Los Angeles County treatment plants meeting California wastewater reclamation criteria
Authors: Yanko William A.
Published: February 2012

ABSTRACT:  Six tertiary treatment water reclamation plants were monitored monthly for enteric viruses for 10 years. Secondary treatment removed 99.8% of the detectable viruses. The virus concentrator and assay system detected low levels of native viruses in 74 out of 75 unchlorinated secondary effluent samples. Only l of 590 final effluent samples averaging 1040 L (275 gal) was positive for enteric viruses. These results suggest that the California Title 22 treatment‐based water reclamation standards assure reliable production of essentially virus risk‐free effluents.
Mass flux of organic chemicals through polyethylene geomembranes
Authors: Park Jae K. , Nibras Mir
Published: February 2012

ABSTRACT:  Lining of waste storage and disposal sites is a common practice to prevent hazardous waste constituents from migrating out of the facility into the surrounding environment. Recently, geomembranes have been widely used to line the waste storage and disposal sites and are expected to be even more common in the future. However, there are not enough data available on the mass transport of organic chemicals through geomembranes by the physicochemical process of partition and diffusion. In this study, partition and diffusion coefficients were measured using a gravimetric method for high‐density polyethylene (HDPE) geomembrane in acetone, chlorobenzene, ethyl acetate, ethylbenzene, n‐hexane, methylene chloride (MC), n‐octane, toluene, trichloroethylene (TCE), and m‐xylene. Sorption tests were also conducted with mixtures of TCE, MC, toluene, gasoline, and aqueous solutions of TCE, MC, toluene, and m‐xylene. The effect of geomembrane thickness on the mass flux parameters was also evaluated. A mathematical model with a time‐dependent diffusion coefficient successfully simulated sorption curves of pure chemicals. The partition and diffusion coefficients of individual organic compounds in a mixture were accurately predicted from the mass‐transport parameters of individual pure chemicals by multiplying them with their mole fractions. Low‐density polyethylene geomembranes had approximately 4 times and 10 times greater partition and diffusion coefficients than HDPE geomembranes, respectively. A mathematical model together with the experimentally determined parameters was used to predict the mass flux of selected organic chemicals present in gasoline through a 10.2‐cm (4‐in.) HDPE pipe (0.4‐cm [0.16‐in.] thick).
Theoretical aspects of bulking in activated sludge
Authors: Hermanowicz Slawomir W.
Published: February 2012

ABSTRACT:  Percolation theory was applied in a theoretical analysis of bulking of activated sludge caused by filamentous microorganisms. Dimensionless filament concentration was defined as L = TEFLv · d2 (where TEFLv = total extended filament length per unit volume, d = length of an individual filament). For L less than a critical value L* , sludge settling is not affected. For L > L* sludge settling is impaired. The critical value L* was theoretically estimated at 0.90 and compared with experimental data reported in the literature. Settling and compression of sludge in a sludge volume index test was analyzed. Elasticity modulus of compressed sludge was related to solids concentration.
Determination of organic pollutants in land applied municipal wastewater sludges by toxicity characteristic leaching procedure (TCLP) and extraction procedure toxicity test (EP)
Authors: Dietrich Andrea M. , Chesnutt Sheryl A. , Stone Lori A. , Gallagher Daniel L.
Published: February 2012

ABSTRACT:  Triplicate wastewater sludge samples, from three small municipal facilities that received no industrial inputs, were analyzed by the Extraction Procedure Toxicity Test (EP) and Toxicity Characteristic Leaching Procedure (TCLP). These tests evaluate the potential for organic and inorganic chemicals to leach from the sludge. Six surrogate chemicals were spiked into the sludges to monitor recoveries of specific chemicals by the two procedures. The recoveries for the surrogate chemical spiked into the sludges were low (0.1‐33%) and variable for both tests. EP and TCLP tests performed similarly in that both tests yielded highly variable results in terms of the number of chemicals and the concentrations detected in the replicate samples. Only four organic pollutants (p‐cresol, dichlorodimethoxybenzene, dimethylpentanol, and tetramethylbutylphenol), at microgram per kilogram concentrations, were identified in the sludge samples. Based on this research, few organic pollutants appear to be leached from municipal‐only wastewater sludges.
A study of the precision of lead measurements at concentrations near the method limit of detection
Authors: Berthouex Paul M.
Published: February 2012

ABSTRACT:  Many problems in environmental quality require measurements on chemicals that are expected to be absent or to exist at very low concentrations. Test specimens delivered to the laboratory for analysis will contain literally “next to nothing” which may lead to some observations being reported as “below the limit of detection.” The limit of detection is a statistical concept that is intended to reflect the magnitude of unavoidable random fluctuations in measurements at these low concentrations. The purpose of this study was to generate a collection of measurements on samples that have low concentrations, at or near the limit of detection. The results show the magnitude of measurement variability at low concentrations and have some important implications regarding the utility of the limit of detection concept in compliance monitoring. An interlaboratory study involving eight laboratories, each of which measured lead on 50 test specimens, provides a large collection of measurements on lead at low concentrations, including concentrations below the laboratories' stated limits of detection. The data show that the variability of measurements at low concentrations was not greater than at the higher concentrations. Lead was not only detected in low concentration specimens, it was also quantified, even at concentrations near and below the limit of detection as it is usually defined, especially when data are interpreted collectively instead of as isolated individual values. The accuracy of measurements may be affected more by bias than by poor precision. The method detection limit (MDL) is a misunderstood and often misused concept. The concept of an MDL does not deal with bias; it is only concerned with precision. It is a quantity that cannot be estimated with great precision. Throwing away measured values because they are “below the limit of detection” discards much useful information and it is recommended that this practice be discontinued.
Competition between methanogens and sulfate reducers: effect of COD:sulfate ratio and acclimation
Authors: McCartney Daryl M. , Oleszkiewicz Jan A.
Published: February 2012

ABSTRACT:  A discussion of the current understanding of the competition between sulfate‐reducing bacteria and methanogens is presented. The effect of artificially elevated sulfate and sulfide levels on anaerobic utilization of lactate was investigated using acclimated and unacclimated inoculum. The lactate degradation pathway was observed to be dependent upon the degree of acclimation to various chemical oxygen demand (COD):sulfate ratios. A ratio of 3.7 g/g resulted in a nonsulfate reducing pathway producing propionate and acetate as products, while a ratio of 1.6 g/g resulted in a sulfate reducing pathway producing only acetate as an organic product. The change in metabolic pathways dramatically changed the relative sulfide sensitivity of the methanogens and the sulfate reducers.
Stripping of volatile organic compounds at full‐scale municipal wastewater treatment plants
Authors: Bell John , Melcer Henryk , Monteith Hugh , Osinga Irwin , Steel Paula
Published: February 2012

ABSTRACT:  A field investigation was carried out at four Ontario municipal wastewater treatment plants to characterize stripping of volatile organic compounds (VOCs) from aerated process vessels. Concentrations of VOCs in the off‐gas and wastewater at aerated grit chambers and aeration basins were measured. Thirty‐two of 36 target VOCs were observed in at least one off‐gas sample from the plants studied. The total emissions for the measured compounds ranged from 2700 to 3900 g/ d or 36 to 50 g/1000 m3 of wastewater treated. Chlorinated VOCs tended to be stripped to a greater extent than nonchlorinated compounds. The data suggest that VOC stripping can be reduced by reducing aeration rates, and that operating and design parameters have an impact on the loss of VOCs.
Enhanced in situ biodegradation of diesei fuel by cyclic vertical water table movement: preliminary studies
Authors: Rainwater Ken , Mayfield Mary P. , Heintz Caryl , Claborn Billy J.
Published: February 2012

ABSTRACT:  Bioremediation normally employs injection of a nutrient solution and an oxygen source into the contaminated zone. The success of the process depends in part on effective transport of the injected substances through the contaminated zone. Field experiences have shown that the transport is limited by the permeability of the subsurface geologic materials and by the stability of the oxygen source. Vertical movement of the water table can serve to alternately expose the bacteria in the contaminated zone to moisture (when the water table is up) and air (when the water table is down and the pores hold some air) while the organic substrate is available from a continuous layer atop the water table or residuals in the unsaturated zone. The cyclic manipulation of the water table may be accomplished by injection and production of water or air in the contaminated zone. In this paper the results of preliminary laboratory experiments dealing with diesel fuel degradation are presented. A mixed culture of diesel‐degrading bacteria was isolated from a soil sample contaminated with bunker oil. Soil columns were used to study the effects of interface movement on the biodegradation of diesel fuel. The bacterial consortium was used to inoculate the soil columns prior to addition of the diesel fuel. After 9 weeks of exposure, with an interface movement cycle period of 48 hours, the effects of the water table manipulation on the amount of diesel fuel degraded were compared to those of an appropriate control with no water table movement. The columns subjected to water table movement had 15% less residual diesel than the static controls after 9 weeks.
Biodegradation rates of crude oil in seawater
Authors: Stewart Philip S. , Tedaldi Dante J. , Lewis Aaron R. , Goldman Eugene
Published: February 2012

ABSTRACT:  Measurements of the rate of biodegradation of crude oil in seawater in laboratory, mesocosm, and field systems from 16 published reports were reviewed and compared. Volumetric biodegradation rates range widely from approximately 0.01 to 1 000 gC/m3‐d. Laboratory studies report rates at the higher end of this range, while field and mesocosm studies, of which there are fewer, suggest much lower rates ranging from 0.01 to 0.3 gC/m3‐d. Possible explanations for the discrepancy between measurements made at different scales are differences in oil concentration and in mixing energy. When temperature‐scaled degradation rates from all systems are plotted versus initial oil concentration on a log‐log scale, the data are approximately linear (r2 = 0.86) over several orders of magnitude. The slope of the regressed line is near 1, indicating that the process can be interpreted as first order with respect to oil concentration. The half‐life for biodegradation is estimated to be approximately two months at 20°C. This analysis suggests that crude oil biodegradation in seawater is relatively slow and indicates that further research is required to bridge the gap between laboratory and field systems.
The HBOD test: a new method for determining biochemical oxygen demand
Authors: Logan Bruce E. , Wagenseller Gretchen A.
Published: February 2012

ABSTRACT:  The conventional biochemical oxygen demand (BOD) test requires a series of sample dilutions and can be very time‐consuming to perform. Although newer oxygen utilization tests based on pressure changes in sealed devices do not require dilutions, they are too expensive to use routinely for wastewater samples. A rapid and inexpensive test is proposed for determining oxygen demand. This procedure, called the headspace biochemical oxygen demand (HBOD) test, uses non‐diluted wastewater samples, because additional oxygen from the container headspace is available to the microorganisms. The total oxygen demand is calculated from oxygen depleted from both the liquid and the air phases in the sealed container. Using samples from 3 wastewater treatment plants, it is shown that the HBOD test, if conducted over a 5‐day period, provides similar results to the BOD test. The three main advantages of the HBOD test are that the test can be performed more easily than the BOD test because no sample dilutions are necessary, the oxygen demand determined within a shorter period of time (24–36 h) can provide an accurate prediction of the 5‐day value, and the experimental conditions used in the HBOD test more accurately reproduce the hydrodynamic and culture conditions typical of wastewater treatment bioreactors. These advantages make the HBOD test more useful for treatment plant process evaluation and control.
Importance of phase behavior on the removal of residual DNAPLs from porous media by alcohol flooding
Authors: Brandes David , Farley Kevin J.
Published: February 2012

ABSTRACT:  A promising method of accelerating the removal of residual DNAPLs from aquifers involves the mobilization of trapped globules by alcohol flooding. This technology was originally developed in the petroleum industry for the recovery of residual oil after waterflooding. Alcohols can significantly reduce the interfacial tension between the residual DNAPLs and the aqueous phase, allowing for mobilization of trapped globules through pore constrictions. In addition, laboratory batch and column results show that certain alcohols preferentially partition into the DNAPL phase, swelling the residual DNAPL globules considerably and at the same time reducing their density significantly. The swollen DNAPL globules become a relatively continuous phase during flooding, making them much easier to displace than disconnected residuals. Density reduction makes the mobilized DNAPL easier to control, and reduces the potential for further downward migration into uncontaminated portions of the aquifer. Laboratory column results confirm that residual trichloroethylene and tetrachloroethylene globules can be effectively removed from glass bead packings at low upflow gradients using preferentially DNAPL‐soluble alcohols.
Laboratory‐scale evaluation of aerobic fluidized bed reactors for the biotreatment of a synthetic, high‐strength chemical industry waste stream
Authors: Edwards Daniel E. , Adams William J. , Heitkamp Michael A.
Published: February 2012

ABSTRACT:  Laboratory‐scale fluidized bed reactors (FBRs) containing either sand or granular activated carbon (GAC) as biocarriers for immobilized bacteria were evaluated for biotreatment of chemical industry wastes. The FBRs were fed high levels of a synthetic waste stream containing aniline (ANL), methyl ethyl ketone (MEK), p‐nitrophenol (PNP) and sodium formate (FRM) at concentrations increasing from approximately 3 600 mg/L total chemical oxygen demand (COD) up to 17 000 mg/L COD. Microbial biomass attached to the GAC increased from 15 000 mg/L at a COD loading of 3.2 Kg COD m‐3 d‐1 to over 40 000 mg/L at a maximum COD loading of 16.0 Kg COD m‐3 d‐1. The sand was colonized slower during start‐up but supported biomass levels of 2 600 to 20 000 mg/L at COD loadings up to 9.6 COD m‐3 d‐3. Scanning electron microscopy confirmed biomass measurements and showed that high levels of bacteria were retained on GAC after a toxic surge in COD loading, but were significantly reduced in the sand reactor resulting in diminished performance. Specific chemical analyses showed over 99% removal of organic feed components by both reactors throughout the study. The sand reactor study was terminated early due to its inability to handle an accidental surge in COD loading. Biological solids production from the GAC reactor ranged from 0.056 to 0.184 g solids/g COD removed. The GAC reactor demonstrated a greater ability to handle rapid increases in COD loading (for adsorbable chemicals) than the sand reactor. This study has increased fundamental understanding of the operation and performance of FBRs treating a representative chemical industry waste stream and has demonstrated some advantages of GAC over sand as a biocarrier.
The role of water in sludge dewatering
Authors: Vesilind P. Aarne
Published: February 2012

ABSTRACT:  While the dewatering of wastewater sludges has received considerable research attention, it has been assumed that the water continuum surrounding the sludge particles has the physical properties of bulk water. This paper suggests that such an assumption may not be valid. The existence of vicinal water, consisting of ordered and layered water molecules on the surfaces of submerged solids, is demonstrated using research from various disciplines. The meaning of “bound water” as used in sludge technology is discussed, and it is shown that bound water can be defined in several ways, depending on the test used. It seems reasonable that bound water as it is usually defined actually consists of three different types of water—water captured in the interstitial spaces within floes and within cells, vicinal water on the surfaces of solids, and water of hydration. Only some of the interstitial water can be removed by mechanical dewatering. Because of the large surface area of sludge particles, including living cells, it is likely that much of the bound water is vicinal water, and this cannot be removed mechanically. The determination of the various fractions of these waters may lead to a better understanding of mechanical sludge dewatering.
Anaerobic treatment of a simulated high‐strength industrial wastewater containing chlorophenols
Authors: Flora Joseph R. V. , Suidan Makram T. , Wuellner Alice M. , Boyer Terrence K.
Published: February 2012

ABSTRACT:  An anaerobic fluidized‐bed granular activated carbon (GAC) reactor employing carbon replacement was evaluated for the treatment of a simulated high‐strength industrial wastewater containing inhibitory concentrations of chlorophenols. The reactor was fed 2 000 to 5 900 mg/L acetic acid; 1 000 to 3 000 mg/L phenol; 1 200 mg/L ortho‐chlorophenol (2‐CP); 600 mg/L 2,4‐dichlorophenol (2,4‐DCP); and 150 mg/L 2,4,6‐trichlorophenol (2,4,6‐TCP). The effects of varying the carbon replacement rate, the bulk operating pH, and the organic loading on reactor performance were investigated. The system was highly effective for treating the wastewater and an overall chemical oxygen demand (COD) removal greater than 98% was achieved. Carbon replacement resulting in a GAC solids mean retention time (SMRT) of 100 days was necessary to control the buildup of an inhibitory degradation byproduct, para‐chlorophenol (4‐CP).
An economic evaluation of biological removal of heavy metals from wastewater sludge
Authors: Couillard Denis , Mercier Guy
Published: February 2012

ABSTRACT:  An economic evaluation was performed for various sludge management practices, including the biological process of metal solubilization for digested and undigested sludges, and the traditional methods of sludge management (landfill, incineration, co‐incineration, and the land spreading of liquid or dewatered sludges for agriculture). Biological solubilization (also called bacterial leaching), including lime neutralization and land spreading, was less expensive for undigested than for digested sludge, and was competitive with land spreading of non‐decontaminated dewatered sludge for a plant treating 388 000 m3/d of wastewater. These two management practices are approximately equivalent and are less costly than all other options considered. However, for a plant treating 20 000 m3 of wastewater per day, metal solubilization was 43% more costly than the frequently practiced application of dewatered sludge onto agricultural land. For both plants (388 000 and 20 000), decontamination, followed by lime stabilization and land spreading, had less of an environmental impact than any of the other management options examined.
Investigation of hypothesized anaerobic stabilization mechanisms in biological nutrient removal systems
Authors: Wable Milind V. , Randall Clifford W.
Published: February 2012

ABSTRACT:  Anaerobic stabilization (AnS) is denned as difference between actual and theoretical oxygen use in activated sludge systems with anaerobic selectors. AnS‐related oxygen savings translate into potentially lower aeration power costs. A comprehensive electron balance approach was developed for more accurate determination of AnS, along with procedures for in‐situ oxygen uptake rate (OUR) measurement and analysis of dissolved gases by vacuum stripping. Lab‐scale anaerobic/oxic (A/O) and anaerobic/anoxic/oxic (A2/O) systems operated under various conditions yielded AnS values of 15‐55% of the theoretical oxygen requirement. Hydrogen and methane production together explained less than 1% of AnS, except when the A/O feed was supplemented with formate, in which case methane production explained about 19% of AnS. Stripping of reduced volatiles explained less than 1% of AnS in both systems. Kinetic limitations of the chemical oxygen demand (COD) test were not found to be significant in explaining AnS, but thermodynamic limitations were identified as potentially capable of explaining a significant fraction of AnS. Mechanisms are hypothesized that can partially explain AnS based on the results of this study.
Metal removal by soil washing for an iron oxide coated sandy soil
Authors: Van Benschoten John E. , Reed Brian E. , Matsumoto Mark R. , McGarvey P. J.
Published: February 2012

ABSTRACT:  A contaminated, iron oxide coated (15.5% Fe203), sandy soil was studied to evaluate the effectiveness of conventional soil‐washing extractants for metal removal. Metals of interest included As, Cu, Pb, Hg, and Zn. The extractant solutions were HC1, HN03, H2S04, EDTA and NH2OH · HC1. Experiments assessed effects of extractant strength and contact time. Individual soil size fractions were studied for the various extractants. Metal‐binding mechanisms were evaluated using a sequential extraction procedure. Metals in all size classes were bound strongly, presumably by an Fe oxide coating observed on the sandy soil. From an analysis of particle size fractions, contaminated soil metal concentration correlated approximately with the surface area/volume ratio of soil particles, suggesting that the metals were associated with soil surfaces. During soil washing, a typical rapid metal release in HC1 occurred initially, followed by a much slower step. The fraction associated with the slow metal release correlated reasonably well with the residual metal fraction. Although sandy soils often are good candidates for soil washing, surface coatings may make metal extraction for even sandy soils difficult.
Emissions of air toxics from wastewater treatment plants
Authors: Mayer G. J. , Cheng I. S. , Pau P. , Mohamed F.
Published: February 2012

ABSTRACT:  Recent California legislation required the City of Los Angeles to prepare air toxics emissions inventories at its four wastewater treatment plants. This paper presents the results of these inventories, including descriptions of available estimation methods, rationale for method selection, intercomparisons of available methods, and comparisons of emissions by treatment plants. Results of required health risk assessments are also discussed. Observations on the emission inventory process at wastewater treatment plants are offered.
Biological treatment of hypersaline wastewater by a biofilm of halophilic bacteria
Authors: Woolard Craig R. , Irvine Robert L.
Published: February 2012

ABSTRACT:  Each year, billions of gallons of wastewaters containing high concentrations of salt (>3.5% w/v) and waste organics are generated by industry. Biological treatment of these hypersaline waste brines to remove organics could reduce the environmental impact and cost of waste disposal. Unfortunately, the salinity of many waste brines makes them difficult to treat with conventional waste treatment cultures. This paper demonstrates that heterotrophic, halophilic organisms can be used to remove phenol from a synthetic waste brine containing 15% salt. The reactor system used in this study was a novel periodically operated biofilm reactor, the Sequencing Batch Biofilm Reactor (SBBR). The SBBR uses permeable silicone tubing to supply oxygen to the reactor. A biofilm of halophiles isolated from the Great Salt Lake, Utah, ecosystem readily developed on the tubing surface and degraded waste organics. The experimental results presented herein demonstrate that the SBBR can produce a stable, high‐quality effluent despite fluctuations in influent phenol concentration. The results of periodic track studies illustrate that biomass accumulation increases oxygen demand but does not significantly improve overall reactor performance
A Simplified Technique for Restoring Interproximal Root Surface Lesions
Authors: Mennito AS , Renne WG
Published: February 2012

PURPOSE

Interproximal root surface caries can often be very difficult to restore due to their lack of direct access and location to the gingiva. This article provides a technique to simplify restoring interproximal root surface lesions. This technique conserves tooth structure, utilizes glass ionomer as the definitive restorative material, and requires very little finishing once the material is fully set.
Degree of polarization as a measurable quantity for a quantum optical field containing variously polarized photons
Authors: Michalik Lukasz , Domanski Andrzej
Published: February 2012

We focus on a comparison between the classical and quantum descriptions of the degree of polarization of an optical field. A quantum field containing photons with various states of polarization and which propagate in the same direction in free space one after another (a so called photon beam) is analyzed. We show that the formulated definition of degree of polarization for this quantum field leads to a measurable quantity. The concept of a thought experiment is presented.
Phase transitions of quasistationary states in the Hamiltonian Mean Field model
Authors: Buyl Pierre , Fanelli Duccio , Ruffo Stefano
Published: February 2012

The out-of equilibrium dynamics of the Hamiltonian Mean Field (HMF) model is studied in presence of an externally imposed magnetic field h. Lynden-Bell’s theory of violent relaxation is revisited and shown to adequately capture the system dynamics, as revealed by direct Vlasov based numerical simulations in the limit of vanishing field. This includes the existence of an out-of-equilibrium phase transition separating magnetized and non magnetized phases. We also monitor the fluctuations in time of the magnetization, which allows us to elaborate on the choice of the correct order parameter when challenging the performance of Lynden-Bell’s theory. The presence of the field h removes the phase transition, as it happens at equilibrium. Moreover, regions with negative susceptibility are numerically found to occur, in agreement with the predictions of the theory.
"Goddesses of Flesh and Metal"
Authors: Salamon Hagar , Juhasz Esther
Published: February 2012

In the nineteenth and early twentieth centuries, the Tunisian Jewish female body was subjected to a dramatic fattening process in preparation for marriage. Immediately following the girl’s engagement, her body became the focus of an intense transformative regimen aimed at achieving the aesthetic ideals of dramatic weight gain and “shining and whitening” of the skin. This paper offers a critical reading of the representation of the female body in postcards and travelogues, in descriptions written by members of the Tunisian Jewish community, and in interviews conducted with group members now living in Israel. The meeting of these voices called for a multidimensional examination of central themes including the ideal female body, its boundaries, and transgressions of those boundaries; mechanisms of control; and the complex relationships between honor and shame and between attraction and repulsion. Hence, the full, rounded bodies of Tunisian Jewish brides were sites of transformation where these multiple meanings came together in complex and at times contrasting ways.
Women as Agents of Grassroots Change
Authors: Bordat Stephanie Willman , Davis Susan Schaefer , Kouzzi Saida
Published: February 2012

Numerous recent initiatives in Morocco aim to promote women’s empowerment in the country’s current climate of legal reform, national and international development, and rising Islamism. The authors employ a holistic definition of empowerment that integrates both individual and collective processes that develop women’s capacities to increase their ability to make choices and have control over their lives, take action, and mobilize to impact the world around them. In so doing, the authors demonstrate how both popular human and legal rights education programs and economic development initiatives are needed to attain such empowerment. This article describes several women-run grassroots-level non-governmental programs that address women’s legal and economic development. It illustrates the ways in which these programs can operate as tools to empower women individually and collectively to act as agents for change and suggests contrasts between these initiatives and those used by ideology-based groups. The article also proposes future inquiry into the ways in which initiatives that claim to empower women may be assessed at the micro-level of the project strategy’s impact on the participants themselves.
Colorectal Cancer Protection and Colonoscopy
Authors: Shrestha UK
Published: February 2012

DOI: http://dx.doi.org/10.3126/njms.v1i1.5786Nepal Journal of Medical Sciences. 2012; 1(1): 1-2
Outcome of Extracorporeal Shock Wave Lithotripsy in Western Region of Nepal
Authors: Ghimire P , Yogi N , Acharya GB
Published: February 2012

Background: Extracorporeal shock wave lithotripsy (ESWL) is an effective non-invasive method for management of urinary tract stones. It was introduced for the first time in Pokhara 1 year back. This study aims to study the efficacy of ESWL in removal of renal and ureteric calculus in relation to the stone size and location and potential adverse effect of the procedure. Methods: It is a prospective observational study carried out in 112 cases undergoing elective ESWL for solitary urolithiasis during a period of 1 year (August 2010- August 2011). Number of sessions required for successful fragmentation and clearance of stones were studied according to their size and position along with the complications encountered. Results: The success rate of ESWL was found to be 91.1% for solitary urolithiasis. The mean number of sessions required for success was found to increase according to increase in size of the stones whereas it was almost similar for various locations. Complications were encountered in 25% of cases. Conclusion: Stone size was found to be the most important predictor in successful outcome of ESWL and the procedure is quite favorable for stones less than 20 mm. Keywords: ESWL; renal stones; ureteric stones DOI: http://dx.doi.org/10.3126/njms.v1i1.5787   Nepal Journal of Medical Sciences. 2012; 1(1): 3-6
An Experience of Limbal Autologous Free Conjunctival Grafting in Cases of Pterygium in Rural Western Hilly Region of Nepal
Authors: Bastola P
Published: February 2012

Background: The study was set in a remote western hilly part of Nepal in the communities of Gulmi, Arghakhnchi and Palpa district of Nepal after seeing the high prevalence of pterygium in those communities.The main purpose of the study was to determine the outcome of free limbal autologous conjunctival grafting from supero temporal quadrant of the eyeball, in cases of pterygium undergoing surgery. Methods: Patients undergoing surgery were evaluated preoperatively, in all cases limbal based supero temporal free autologous conjunctival graft was used, except in cases where it was contraindicated. All the patients’ data were enrolled in to a specifically made proforma for the study. Cases undergoing surgery were followed up, up to one year period. Statistical analysis was performed using Statistical Package for Social Services version 12.0 (SPSS). Results: Hundred and fifteen eyes of 115 patients were included in the study. Ten (8.6%) cases had primary nasal and temporal pterygia both, while five (4.3%) cases in the study were recurrent pterygium. Commonest complication post operatively encountered were foreign body sensation, ocular discomfort, redness, while two cases had flap retraction which was sutured back. None of the patients had recurrence of the pterygia till the last follow up period. Conclusion: This study has shown that free limbal based autologous conjunctival graft is one of the safe surgical techniques for Pterygium treatment with excellent outcome especially in those parts of area where modern pterygium surgery are difficult to do with various restrictions. Keywords: Pterygium; limbal autologous grafting; graft retraction DOI: http://dx.doi.org/10.3126/njms.v1i1.5789   Nepal Journal of Medical Sciences. 2012; 1(1): 11-14
Scenario of Poisoning Cases in Adults Admitted in Manipal Teaching Hospital, Pokhara, Nepal
Authors: Maskey A , Parajuli M , Kohli SC , Baral S , Basnet S , Poudel N
Published: February 2012

Background: Acute poisoning is a common medical emergency encountered in practice. The knowledge profile of poisoning cases encountered in a particular area is useful to prepare health care professionals to handle these emergencies efficiently. Methods: This retrospective study was carried out by perusing and analyzing the hospital records of all the 160 cases of poisoning admitted above 15 years of age to Manipal Teaching Hospital, Pokhara, Nepal from July 2008 to June 2011. Results: The maximum percentage (43.1%) of poisoning cases occurred in younger age group (15-24 years). Gender distribution of poisoning cases showed steep rise in males after 40 years of age with male to female ratio of 3.8:1. Suicidal poisoning are most common 122 (76%). Organophosphorus compounds were most common cause of poisoning 67 (41.9%). Conclusion: Highest number of cases of poisoning was encountered in younger age group 15-24 years. There was steep rise of poisoning cases after 40 years of age in males (M:F=3.8:1). Organophosphorus compounds were most commonly used for this purpose. Keywords: Acute poisoning; organophosphorus; snake bite; suicide DOI: http://dx.doi.org/10.3126/njms.v1i1.5792   Nepal Journal of Medical Sciences. 2012; 1(1): 23-26
Foreign Body in the Esophagus-Comparison Between Adult and Pediatric Population
Authors: Koirala K , Rai S , Chhetri S , Shah R
Published: February 2012

Background: Foreign body (FB) impaction in the esophagus is a common emergency in all age groups. In the children coins are the commonest foreign bodies while bones have been found as the commonest in adults. Methods: This is a retrospective study comparing FB in the esophagus in adult and pediatric population between June 2007 and May 2010 in Manipal Teaching Hospital, Pokhara, Nepal. Most of the patients underwent rigid esophagoscopy and FB removal; few were removed under anesthesia by the anesthesiologists. Comparison was done in terms of pattern of FB, their site of impaction and relative ease of removal. Data were collected from the case file available from the medical record department and analysed using SPSS 11.6. Results: A total of 63 cases were included in this study. Out of which 28 (44.4%) patients were children and 35 (55.5%) were adults. Coin was the most common foreign body in the pediatric population (82.1%) whereas bones were the commonest ones (91.4%) in adults. In the pediatric population the commonest site of impaction was upper esophagus (92.8%) whereas mid esophagus was the commonest site (65.7%) in adults. Conclusion:There are differences in various aspects of impacted foreign bodies in esophagus in adult and pediatric populations. Coins being the commonest foreign bodies in children are relatively easier to remove due to their higher location and less chances of trauma. Contrary in the adults, bones being the commonest foreign body are difficult to remove due to the lower location and chances of trauma. Keywords: Foreign body; esophagus; rigid bronchoscopy DOI: http://dx.doi.org/10.3126/njms.v1i1.5797   Nepal Journal of Medical Sciences. 2012; 1(1): 42-44
Pattern of Mandibular Fractures in Western Region of Nepal
Authors: Adhikari RB , Karmacharya A , Malla N
Published: February 2012

Background: Mandible and nasal bones are the most prominent part of the facial skeleton and are commonly fractured. Its fractures result in severe loss of function and disfigurement. This study was conducted to evaluate and analyze the pattern of mandibular fractures in Western region of Nepal. Methods: This hospital based, descriptive, cross sectional study included 120 patients treated in the Department of Dental surgery, Manipal Teaching Hospital, Pokhara, Nepal from 1st August 2008 to1st December2011.These patients were examined both clinically and radiologically for mandibular fractures. Data concerning age, gender, causes of fracture and sites of fracture were analyzed. Results: The age range was 3-80 years (mean26.3±13.43years) and male to female ratio was 1:0.69. Highest frequency was seen in 21-30 years age group. The leading cause of mandibular fracture was road traffic accident (n=56; 46.6%), followed by accidental fall from height or tree (n=28; 23.3%), physical assault (n=18; 15%), sports injuries (n=12; 10%), industrial accidents (n=4; 3.3%) while 2 cases (1.6%) were associated with other causes. The most common site was parasymphysis (n=42; 35%) followed body (n=22; 18.33%), angle (n=20; 16.6%), condyle (n=18;15%) and symphysis (n=10;8.33%). Conclusion: The study reveals that the majority of the patients were young adult male. The most common etiological factor was road traffic accident and commonly fractured site was the parasymphysis. Keywords: Mandible fracture; etiology; road traffic accidents; pattern DOI: http://dx.doi.org/10.3126/njms.v1i1.5798   Nepal Journal of Medical Sciences. 2012; 1(1): 45-48
A Case of Polyneuropathy Following a Single Dose of Diethylcarbamazine and Albendazole During Mass Administration of Drug - A Case Report
Authors: Kohli SC , Shrestha UK , Alurkar VM , Maskey A , Parajuli M , Paudel N , Pradhananga S , Vaidya S
Published: February 2012

The global program to eliminate Lymphatic Filariasis created by The World Health organization in 1997 is based on mass administration of single annual doses of diethylcarbamazine ( DEC) plus albendazole in non African regions and of albendazole plus ivermectin in Africa. The usual side effects of DEC treatment include fever, chills, arthralgia, headaches, nausea, and vomiting. Albendazole is associated with relatively few side effects consisting of occasional nausea, vomiting, abdominal pain, headache, reversible alopecia, elevated aminotransferases and rarely leucopenia and rash. We report a case of polyneuropathy in a young individual following DEC and albendazole during mass drug administration. Keywords: Albendazole; DEC; Polyneuropathy. DOI: http://dx.doi.org/10.3126/njms.v1i1.5800   Nepal Journal of Medical Sciences. 2012; 1(1): 56-58
Refractory Status Epilepticus Following Ingestion of Organochlorine Pesticide Endosulphan- A Case Report
Authors: Bhattarai S , Kohli SC
Published: February 2012

A 22 years old female was brought to emergency department of Manipal teaching hospital, Pokhara, Nepal with suicidal consumption of 35 grams of endosulphan .She presented with status epilepticus not responding to intravenous benzodiazepine, loading doses of phenytoin and phenobarbitone and was managed by intravenous propofol and subsequently with continuous infusion of midazolam. Refractory status epilepticus is a common problem following ingestion of endosulphan and unless aggressively treated, it is associated with high morbidity and mortality. Endosulphan poisoning is often completely reversible with immediate and appropriate treatment. Keywords: Endosulphan poisoning; seizure; refractory status epilepticus; benzodiazepine; propofol. DOI: http://dx.doi.org/10.3126/njms.v1i1.5801   Nepal Journal of Medical Sciences. 2012; 1(1): 59-61
Bacteriological and physico-chemical properties of the Gulshan Lake, Dhaka
Authors: Saha Mihir Lal , Bari Tahmina , Khan Mahbubar Rahman , Hoque Sirajul
Published: February 2012

Seasonal variation on bacterial load irrespective of heterotrophic and enteric bacteria was noticed in Gulshan lack of Dhaka Metropolitan city. The lowest number (1.56×106 cfu/100 ml) in the summer and the highest (19.03×106 cfu/100 ml) were recorded during winter. Among the isolated bacteria 32 were studied in details and provisionally identified as Bacillus cereus (1), B. sphaericus (1), B. subtilis (1), B. brevis (2), B. pasteuri (1), B. stearothermophilus (1), B. azotoformans (1), B. pantothenticus (1), B. licheniformis (1), B. circulans (1), B. insolitus (1), Planococcus citrius (1), Micrococcus sedentarius (1), Pseudomonas. syringae (4), P. aeruginosa (1), P. cichorii (1), Escherichia (2), Klebsiella (1), Aeromonas (1), Proteus (1), Enterobacter (1), Salmonella (2), Yersinia (1), Shigella (1), Hafnia (1), and Alcaligens (1). The temperature and pH of the water samples varied between 24.3 and 29.2º C and 6.54 and 7.12, respectively. Chemical contents (mg/l) like NH4 +-N, NO3 --N and phosphorus ranged 3.06 (Winter) to 14.86 (Summer), 0.32 (in Rainy season) to 13.02 (Summer) and 0.81 (Rainy season) to 1.86 (Summer), respectively. The enteric bacterial load (0.03 × 105 cfu/100 ml in Rainy season to 21.2 × 105 cfu/100 ml in Winter) and the presence of Escherichia, Aeromonas, Enterobacter, Pseudonomas in the samples indicated significant level of microbial pollution of the lake. Key words: Aerobic-heterotrophic; Bacteria; Enteric bacteria; Chemical factorsDOI: http://dx.doi.org/10.3329/bjb.v40i2.9753 Bangladesh J. Bot. 40(2): 105-111, 2011 (December)
Taxonomic revision of the genus Morinda L. (Rubiaceae) in Bangladesh
Authors: Das Sujit C , Rahman M Atiqur
Published: February 2012

The genus Morinda L. (Rubiaceae) has been revised for its species diversity in the flora of Bangladesh. The genus is represented by five species, viz., M. angustifolia Roxb., M. citrifolia L., M. persicaefolia Ham., M. pubescens Smith and M. umbellata L. Of these, M. pubescens Smith is a new record for Bangladesh. A key to the species with vernacular names, descriptions, illustrations, photographs, ecology, uses, geographical distribution and status of occurrence in the flora is provided. Key words: Taxonomy; Morinda; Rubiaceae; Bangladesh DOI: http://dx.doi.org/10.3329/bjb.v40i2.9766 Bangladesh J. Bot. 40(2): 113-120, 2011 (December)
New record of planktonic diatoms from the Sundarban Mangrove Forests, Bangladesh
Authors: Aziz Abdul
Published: February 2012

Botanical expedition to the Sundarban Mangrove Forests in the Bangladesh part revealed the presence of 14 diatom taxa not recorded so far from Bangladesh territory. The taxa are Amphiprora alata Kütz., Chaetoceros pendulus Karsten, Chaetoceros socialis Lauder, Cyclotella comta (Ehr.) Kütz. Thalassionema nitzschioides (Grun.) Meresch, Thalassiosira rotula Meunier, Thalassiosira weisflogii Grun., Lioloma delicatula (Cupp) Hasle, Navicula brekkaensis Petersen fa, Nitzschia inconspicua Grun. fa, Nitzschia romana Grun., Surirella fastuosa var. recedens (Schm.) Cl. Besides these, unidentified species of Chaetoceros sp. and an unidentified centric diatom have been recorded. These newly recorded taxa are described and illustrated. Key words: Phytoplankton; Diatoms; Mangrove; Estuarine algae; Centrales; Pennales DOI: http://dx.doi.org/10.3329/bjb.v40i2.9772   Bangladesh J. Bot. 40(2): 163-169, 2011 (December)