bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of evoked otoacoustic emissions associated with acoustic neuromas
Authors: Telischi Fred F. , Roth Jeffrey , Stagner Barden B. , Lonsbury‐Martin Brenda L. , Balkany Thomas J.
Published: October 2006

Evoked otoacoustic emissions (OAEs) are assumed to reflect healthy outer hair cell function. Over the past few years, evoked OAEs have been shown to be useful as indicators of cochlear hearing loss. Because basic studies have shown that OAEs are extremely sensitive to cochlear anoxia and hypoxia, as well as to the adverse effects of many inner ear diseases, it is possible that these objective tests can provide some insight into the fundamental basis of the hearing loss exhibited by patients with acoustic neuromas.

The primary aim of the present study was to examine the effects of acoustic neuromas on the amplitudes of evoked OAEs and to compare these findings with tumor‐induced hearing levels. To this end, tests of behavioral audiometry, distortion‐product otoacoustic emissions and transiently evoked otoacoustic emissions were performed on 44 patients with verified acoustic neuromas. The results demonstrated that the majority of ears with acoustic neuromas displayed one of two distinct patterns of evoked OAEs: a cochlear pattern or a noncochlear pattern. Although behavioral hearing thresholds were higher with larger tumors, OAE levels exhibited no clear relationship to tumor size.

The present findings support the notion that acoustic neuromas may cause hearing impairment according to two types of influence that act at different levels of the peripheral auditory system. The tumor's cochlear effect on evoked OAE activity is most likely caused by an indirectly mediated compromise of the organ of Corti's vascular supply. It is probable that the direct pressure of the tumor on the eighth cranial nerve is responsible for the observed noncochlear effects.
Acoustic neuroma: Correlation among tumor size, symptoms, and patient age
Authors: Van Leeuwen J. P. P. M. , Cremers C. W. R. J. , Thewissen N. P. M. W. , Harhangi B. S. , Meijer E.
Published: October 2006

Due to improved diagnostic techniques, acoustic neuromas more frequently are detected at an early stage. Subsequent treatment depends on such factors as expected tumor growth rate, tumor size, and patient age. The natural history of acoustic neuromas is still uncertain:

This study was performed to examine possible correlations among tumor size, patient age, signs and symptoms, and duration of symptoms. The study included 164 patients with an acoustic neuroma who were treated at University Hospital Nijmegen, The Netherlands, over a period of 13 years. Comparisons were made between the findings of this study and the reports in the literature. No support was found for any of the correlations mentioned in other studies, and no relationships could be demonstrated between the parameters evaluated in this study. The authors therefore recommend that treatment policies be based only on well‐established correlations.
Modified neoglottis reconstruction following total laryngectomy: Long‐term follow‐up and results
Authors: Brandenburg James H. , Patil Namrata , Swift Edie W.
Published: October 2006

In 1978 a surgical procedure was developed to create a neoglottis from the upper tracheal rings to facilitate speech rehabilitation in patients who had undergone total laryngectomy for carcinoma of the larynx. To date, 45 such procedures have been performed and results indicate rapid postoperative speech rehabilitation in nearly all patients, good long‐term speech results, and low morbidity. This procedure has served as a very successful alternative to the more frequently used tracheoesophageal puncture (TEP) and prosthetic valve technique.
Role of pharyngeal propulsion as an indicator for upper esophageal sphincter myotomy
Authors: Moine Alain , Périé Sophie , Bokowy Christophe , Angelard Bruno , Chaussade Stanislas , Guily Jean Lacau St
Published: October 2006

Thirty‐eight patients with swallowing disorders underwent cricopharyngeal myotomy. The causes of the disorders were muscular in 12 cases, neurologic in 12, cricopharyngeal achalasia in 7, and unknown in 7. Surgery succeeded in 21 patients, gave a partial improvement in 4, and failed in 13. The quality of residual pharyngeal propulsion on clinical, manometric, and radiologic assessment appeared to be a more important predictor of surgical outcome than upper esophageal sphincter relaxation and the major factor in establishing the indications for cricopharyngeal myotomy. Achalasias in the elderly and oculopharyngeal muscular dystrophies had the most favorable outcome.
Squamous cell carcinoma of the oral cavity: A clinicopathologic scoring system for evaluating risk of cervical lymph node metastasis
Authors: Vila Carlos Navarro , Martínez‐Gimeno Carlos , Rodríguez Ernesto Moro , Varela Carmen Lopez
Published: October 2006

A series of 126 cases of squamous cell carcinoma of the oral cavity with neck dissection was studied. Several clinicohistologic parameters and statistical correlation with lymph node metastasis were evaluated. Statistical association with metastasis was found in the following factors: microvascular invasion (P < 6 × 10−7), grade of differentiation (P < .0001), T category (P = .003), tumor thickness (P = .005), inflammatory infiltration (P = .011), tumoral interphase (P = .02), and perineural spread (P = .04). We designed a scoring system based on statistical results that eliminates the need for complex mathematical formulas. We tested this scoring system; cases with scores ranging form 7 to 12, 13 to 16, 17 to 20, and 21 to 30 points showed metastasis in 0%, 20%, 63.6%, and 86.3% of cases, respectively. The differences between these four groups in relation to rate of metastasis were very significant (P = 8 × 10−9). In conclusion, this scoring system is a reliable method of predicting risk of metastasis.
Predicting perceived vulnerability for breast cancer among women with an average breast cancer risk
Authors: Eibner Frauke , Barth Jürgen , Bengel Jürgen
Published: October 2006

Objectives. The purpose of the present study was to investigate predictors of perceived vulnerability for breast cancer in women with an average risk for breast cancer. On the basis of empirical findings that suggested which variables might be associated with perceived vulnerability for breast cancer, we investigated whether knowledge of breast cancer risk factors, cancer worry, intrusions about breast cancer, optimism about not getting cancer and perceived health status have a predictive value for perceived breast cancer vulnerability.

Design. In a 3‐step approach, we recruited 292 women from the general public in Germany who had neither a family history of breast cancer nor breast cancer themselves. After receiving an initial informational letter about study objectives, the women were interviewed by telephone and then asked to fill in a self‐administered questionnaire.

Methods. We used structural equation modelling and hypothesized that each of the included variables has a direct influence on perceived vulnerability for breast cancer.

Results. We found a valid model with acceptable fit indices. Optimism about not getting cancer, intrusions about breast cancer and women's perceived health status explained 32% of the variance of perceived vulnerability for breast cancer. Cancer worry and knowledge about breast cancer did not influence perceived vulnerability for breast cancer.

Conclusion. Perceived vulnerability for breast cancer is associated with health‐related variables more than with knowledge about breast cancer risk factors.
Future‐directed thinking and depression in relapsing‐remitting multiple sclerosis
Authors: Moore Anna C. , MacLeod Andrew K. , Barnes David , Langdon Dawn W.
Published: October 2006

Background.Research has shown that depression is associated with a view of the future characterized by reduced anticipation of future positive experiences, but not necessarily increased anticipation of future negative experiences. The aim of the present study was to investigate how participants with relapsing‐remitting multiple sclerosis (MS) anticipated their future in terms of positive and negative events.

Design.A mixed design compared three groups of participants on a measure of future thinking using an adapted verbal fluency paradigm.

Methods.Depressed MS participants (N= 14), non‐depressed MS participants (N= 28) and healthy control participants (N= 26) were assessed on their ability to generate future positive and negative experiences. A content analysis was also conducted on the responses generated by the MS depressed and MS non‐depressed groups according to whether or not they were related to MS.

Results.The MS depressed group anticipated significantly fewer future positive events than the healthy control group and the MS non‐depressed group. The three groups did not differ in the total numbers of anticipated future negative events, though the MS depressed group did anticipate a significantly higher proportion of MS‐related negative events.

Conclusions.Like depressed but physically healthy individuals, the MS depressed group was characterized by a lack of positive thoughts about the future, rather than an increased number of negative thoughts. The clinical implications of these findings are discussed along with recommendations for future research.
Psychological distress after the occupation: A community cross‐sectional survey from Lebanon
Authors: Roberto Saab Bassem , Chaaya Monique , Eid Fares Jocelyn , Abi Khirs Joseph
Published: October 2006

Objectives. Jezzine inhabitants were exposed to war stressors for 17 years. This study aims at determining the prevalence of psychiatric distress (PD) among Jezzine citizens who were exposed to war for 17 years and to identify associated factors.

Design. Cross‐sectional study.

Methods. A sample of 142 citizens was randomly selected from a population of 5,000. A novel questionnaire was used to collect data on war exposure, socioeconomic and demographic variables. PD was assessed using GHQ‐12. Data were analysed by logistic regression.

Results. PD was found in 26% of Jezzine residents. PD was associated with age, marital status, education, experience of war‐related events, chronic illness and alcohol drinking. After adjusting for all variables, PD remained significantly correlated with older age and low education (odds ratios were 7.59 and 4.28, respectively).

Conclusions. The prevalence of PD among the residents of Jezzine after a year of the Israeli withdrawal was similar to that reported in other communities whether they were, or were not, exposed to war stress. Higher prevalence among older and less educated individuals suggests the presence of a significant age cohort effect and cognitive construal factors for PD among persons chronically exposed to war‐related stressors.
Reactor Dosimetry Study of the Rhode Island Nuclear Science Center
Authors: Holden NE , Reciniello RN , Hu JP , Leith J , Tehan TN
Published: October 2006

The RINSC is a 2 MW light water reactor that has a graphite thermal column, that is used for educational and industrial applications as well as for biological research. A series of measurements and calculations have been performed in this thermal column. Thermoluminescent dosimeter measurements of the neutron dose rate and the gamma-ray dose rate, as well as bare gold foil and cadmium covered gold foil measurements of the thermal and epithermal neutron flux densities are graphically compared to MCNP Monte Carlo calculations.
Characterization of Modified Carbon Nanotubes by TG-MS and Pyrolysis-GC/MS
Authors: Lineberry Q , Buthelezi T , Pan WP
Published: October 2006

Two evolved gas analysis techniques were used to study modified single-wall carbon nanotubes (SWNTs). These techniques were thermogravimetry-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (pyrolysis-GC/MS). Increased weight loss was exhibited in the modified SWNTs below 800°C, which was attributed to the addition of methoxide introduced during the modification. The localized environments of the SWNT provide bonding sites of varying strength that results in the staged evolution of the methoxide masses. The continued evolution of methoxide related masses is a result of the variations in the localized environments of the SWNTs, including the curved ends and various other possible sites along the sidewalls. However, once all the modifications have been removed, the overall structure of the SWNT still remains as intact as the pristine sample as indicated by the slope of the weight loss at higher temperatures.
Coupled Neutron-Gamma Calculations for the LR-0 Experimental Benchmark
Authors: Hordosy G
Published: October 2006

Benchmark calculations were performed for the mockup of a WWER-1000 reactor developed on the test reactor LR-0 in Nuclear Research Institute Rez (Czech Republic). The experimental arrangement is azimuthally and axially shortened, but the radial dimensions and material compositions are identical with the power reactors. The neutron and photon spectra, attenuation coefficients, and spectral indices were calculated and compared with measurements in all representative points of the mockups. The calculations were performed using the mcnp4C Monte Carlo code. A detailed geometrical model was developed. Most calculations were repeated using different nuclear data libraries. In some cases it was found that the difference of measured and calculated values is higher than could be explained by the experimental and calculational error.
Greening of Mortars with Pozzolans
Authors: Bargaheiser K , Nordmeye DH
Published: October 2006

Growing interest in sustainable building has created a strong interest in fly ash and other coal combustion products (CCPs). Emergence of agencies like the U.S. Green Building Council (USGBC) and the Coal Combustion Products Partnership (C2P2) of the USEPA has accelerated this trend. Their primary goal is sustainable development, focusing on environmental and social concerns. More than 30% of the 100 million tons of coal combustion products produced in the U.S. annually are being beneficially used in such things as manufactured stone, ceramic tile, shingles, concrete, aerated cellular concrete blocks, concrete blocks, stuccos, and mortars. The use of CCPs positively impacts the environment. Specifiers, contractors, and industry need to recognize that environmental stewardship today affects our children tomorrow. The features and benefits recognized in pozzolanic mortars reach beyond the technical, environmental, social, and sustainable aspects of this mortar. They signal future generations to track, improve, and develop mortars beyond any of our current technology.
Women's Autonomy and Informed Consent in Microbicides Clinical Trials
Authors: Woodsong Cynthia , MacQueen Kathleen , Namey Emily , Sahay Seema , Morar Neetha , Mlingo Margaret , Mehendale Sanjay
Published: October 2006

Achieving respect for persons is problematic in settings with concepts of autonomy that differ from Western values. For international research, women's autonomy to consent to participation is an increasingly contentious issue. We present data from ancillary studies conducted in preparation for a clinical trial testing the safety and efficacy of topical microbicides, used to prevent HIV infection. These ancillary studies were conducted in seven countries, using qualitative research methods to collect data from female and male community members, and their health care professionals and community leaders. Our findings indicate that by working at the level of the community, couple and individual, researchers may be able to take steps to increase women's ability to make their own independent decisions about participating in research. This approach may, in turn, improve both the conduct and outcomes of research.
Solving Problems of Disclosure Risk While Retaining Key Analytic Uses of Publicly Released Microdata
Authors: O'rourke Joanne McFarland , Roehrig Stephen , Heeringa Steven G. , Reed Beth Glover , Birdsall William C. , Overcashier Margaret , Zidar Kelly
Published: October 2006

Measures used to protect subjects in publicly distributed microdata files often have a significant negative impact on key analytic uses of the data. For example, it may be important to analyze subpopulations within a data file such as racial minorities, yet these subjects may present the greatest disclosure risk because their records tend to stand out or be unique. Files or records that are linkable create another type of disclosure risk—common elements between two files can be used to link files with sensitive data to externally available files that disclose identity. Examples of disclosure limitation methods used to address these types of issues include blanking out data, coarsening response categories, or withholding data altogether. However, the very detail that creates the greatest risk also provides insight into differences that are of greatest interest to analysts. Restricted-use agreements that provide unaltered versions of the data may not be available, or only selectively so. The public-use version of the data is very important because it is likely to be the only one to which most researchers, policy analysts, teaching faculty, and students will ever have access. Hence, it is the version from which much of the utility of the data is extracted and often it effectively becomes the historical record of the data collection. This underscores the importance that the disclosure review committee strikes a good balance between protection and utility. In this paper we describe our disclosure review committee's (DRC) analysis and resulting data protection plans for two national studies and one administrative data system. Three distinct disclosure limitation methods were employed, taking key uses of the data into consideration, to protect respondents while still providing statistically accurate and highly useful public-use data. The techniques include data swapping, microaggregation, and suppression of detailed geographic data. We describe the characteristics of the data sets that led to the selection of these methods, provide measures of the statistical impact, and give details of their implementations so that others may also utilize them. We briefly discuss the composition of our DRC, highlighting what we believe to be the important disciplines and experience represented by the group.
The Effects of Stock and Prerelease Marine Net-Pen Culture on Survival to Adulthood, Age at Maturity, and Fisheries Contribution for Three Stocks of Chinook Salmon in Southeast Alaska
Authors: Thrower Frank , Joyce John E
Published: October 2006

Three stocks of juvenile stream-type Chinook salmon Oncorhynchus tshawytscha were evaluated as part of an ocean ranching and broodstock development program at Little Port Walter, Southeast Alaska. Fish were either cultured in freshwater throughout the presmolt period or moved to marine net-pens with an artificial freshwater lens for five periods (2–210 d); all fish were released on the same day. The fish were tagged with coded wire tags to determine the effect, if any, of stock and duration of marine net-pen culture on precocity, fishery contribution, survival to adulthood, and size in the commercial fisheries relative to traditional freshwater culture. Recoveries of tagged fish in the fisheries and at the hatchery weir indicated significant overall effects of stock on marine survival; the Unuk stock survived better than the Chickamin and King Salmon stocks. Culture overwinter in marine net-pens produced higher survival to adulthood in all stocks but also resulted in higher mortality during culture and a higher proportion of precocious males in one of the stocks. The effects of short-term spring net-pen culture on juvenile Chinook salmon also varied by stock. Unuk and Chickamin stocks cultured for short periods in marine net-pens generally had higher survival to adulthood, similar fishery contribution, and similar precocious maturation rates as their respective freshwater controls, while the King Salmon stock experienced variable marine survival, precocity, and fishery contribution rates. For facilities with limited freshwater or a limited number of fish to release, the use of marine net-pens for short-term culture could help reduce densities, ease rearing space constraints, and maximize adult production. These benefits appear to have stock-specific limitations.
Major and trace elements geochemistry of basalts and trachyphonolites from Huahine Island, Society archipelago (French Polynesia)
Authors: Harnois Luc , Stevenson Ross K.
Published: October 2006

Basalts and trachyphonolites from Huahine Island (Society archipelago) have been analyzed for major elements and several trace elements (including rare earth elements). Eight basalts from the nearby Bora Bora Island were also analyzed for comparison. Ni-MgO, Ni-Ba, and Ni-Rb modeling indicates that the abundances of these elements in Huahine basalts cannot be entirely the result of crystallization and/or accumulation of olivine and reflect a variability already present in a heterogeneous source, a conclusion supported by Pb and Ce data. The chemical variability of Huahine basalts, with respect to several trace elements, can be explained by contamination of the differentiating basaltic melt by a sedimentary reservoir. The same trace element data also suggest that Huahine trachyphonolites can be derived from basaltic magma by assimilation-fractional crystallization or from partial melting of a hawaiite.
Zoogleal Clusters and Sludge Dewatering Potential in an Industrial Activated‐Sludge Wastewater Treatment Plant
Authors: Lajoie Curtis A. , Layton Alice C. , Gregory Ingrid R. , Sayler Gary S. , Taylor Don E. , Meyers Arthur J.
Published: October 2006

Microscopic observations at an industrial wastewater treatment facility were conducted over a period of approximately 4 years to determine the relationship between the abundance of zoogleal clusters and sludge dewatering potential. Dewatering potential, measured as centrifuged solids content, was determined in sludge samples from an aeration basin. The abundance of zoogleal clusters and centrifuged solids content were negatively correlated, as determined by linear regression (r2 0.62). Curve‐fitting using an exponentially weighted moving average and a polynomial equation yielded r2 0.82. Probing with small ribosomal subunit RNA (16S rRNA) oligonucleotide probes (ZRA and ZBE) indicated that the microorganisms forming these zoogleal clusters were not the same as previously classified Zoogloea ramigera strains (members of the beta subclass of Proteobacteria) isolated from other wastewater treatment systems. The microorganisms responsible for zoogleal cluster formation were identified using micromanipulator separation, cultivation, and 16S rRNA analysis. Distance matrix tree analysis of isolated strains revealed the presence of two types of microorganisms, referred to as mzt and mzl strains. The mzt isolates grouped most closely with members of the genus Thauera, whereas the mzl isolates grouped more closely with members of the genus Hydrogenophaga. Using 16S rRNA methods, a probe complementary to members of the genus Thauera (MZ1; S‐G‐Thau‐0646‐a‐A‐19) was designed to target mzt strains. Whole‐cell hybridization with a fluorescein‐labeled probe, coupled with epifluorescence microscopy, was used to verify the identity of the zoogleal cluster‐forming organisms. Results indicated that the MZ1 probe hybridized specifically with zoogleal clusters present in sludge.
Henry's Law Constants for Paint Solvents and Their Implications on Volatile Organic Compound Emissions from Automotive Painting
Authors: Kim Byung R. , Kalis Edward M. , Dewulf Thomas , Andrews Kari M.
Published: October 2006

This paper describes experimental results of equilibrium partitioning of several significant paint solvents and formaldehyde between air and water to quantify the potential for capturing and retaining the constituents in spraybooth scrubber water during automotive painting. The compounds studied are toluene, n‐butanol, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, and n‐methyl‐2‐pyrrolidinone. A set of field data collected at a Ford Motor Company assembly plant was also analyzed to determine whether data were consistent with the equilibrium phenomenon. The primary findings include: (a) There were more than six orders of magnitude difference in the Henry's law constants among the solvents studied. A solvent with a smaller constant is less easily stripped from water. The Henry's law constants decrease in the following order: toluene and xylenes methyl ethyl ketone n‐butanol butyl cellosolve acetate butyl cellosolve formaldehyde butyl carbitol n‐methyl‐2‐pyrrolidinone. (b) Field data showed accumulation of n‐methyl‐2‐pyrrolidinone and stable concentrations of butyl carbitol, butyl cellosolve, and n‐butanol in the paint‐sludge pit water during a 2‐month period. Stable concentrations indicate a continuous, balanced capture and stripping of the solvents. Data were consistent with measured Henry's law constants. (c) The low Henry's law constant for formaldehyde is the result of the fact that it is hydrated when dissolved in water.
Comparison of Anaerobic Acrylic Acid Biotransformation in Single‐ and Two‐Stage pH‐Stat Completely Stirred Tank Reactor Systems
Authors: Demirer Göksel N. , Speece Richard E.
Published: October 2006

Performance of single‐ and two‐stage pH‐stat completely stirred tank reactor (CSTR) systems for anaerobic acrylic acid biotransformation was investigated and compared. In the experiments, acetate was added with acrylic acid. Acetate concentration in both single‐ and two‐stage reactors was continuously maintained at a nonlimiting concentration of 2000 200 mg/L using a computercontrolled pH‐stat system to allow observation of the effect of acrylate biotransformation on the more sensitive methanogenic step. For this purpose, conventional (one‐stage) and two‐stage pH‐stat CSTR systems with the same acrylic acid loading strategy were operated under the same conditions, and their performances were compared. The food‐to‐microorganism ratio in the first stage of the two‐stage system was maintained at approximately two times that of the one‐stage system. Furthermore, relatively high acrylate concentrations and dilution rateswere achieved in the first stage of the two‐stage system. Results revealed that the two‐stage pH‐stat CSTR system provided better effluent quality and more stable operation with the toxic effects of acrylic acid and its intermediate products than the single‐stage system
High‐Sulfate, High‐Chemical Oxygen Demand Wastewater Treatment Using Aerated Methanogenic Fluidized Beds
Authors: Zitomer D.H. , Shrout J.D.
Published: October 2006

Many industrial wastewaters have both high organic pollution and sulfate (SO42) concentrations. Although biological conversion of organics to methane may be an economical chemical oxygen demand (COD) removal option, significant inhibition of methane production results from reduction of SO42 to hydrogen sulfide (H2S), which is inhibitory to methanogenic microorganisms. Therefore, sulfatecontaining wastewater is often not amenable to conventional anaerobic treatment. Recently, limited aeration of recycle flow to hybrid and baffled reactors has been used to treat this wastewater and has been shown to reduce aqueous H2S concentrations by causing production of uninhibitory sulfur (S°) and thiosulfate (S2O32) as well as gas stripping volatile H2S. In this study, directly aerated methanogenic fluidized bed reactors (FBRs) achieved increased methane production compared tostrictly anaerobic FBRs treating high‐sulfate wastewater. Oxygen transfer satisfying up to 28% of the COD load resulted in maximum specific oxygen utilization rates of 0.20 mg oxygen/g volatile solids min, with significant, concomitant methane production. Under typically inhibitory SO42 loading, higher aeration caused increased effluent SO42, increased H2S mass in the offgas, and lower reactor H2S concentration. As a result, COD removal increased from 25% for a strictly anaerobic FBR to 87% for an aerated FBR. In addition, aerated systems required significantly less alkalinity supplementation to maintain a pH value of 7, ostensibly because of stripping of acidic carbon dioxide. The potential pH increase associated with aeration also shifts sulfide speciation to less toxic bisulfide. Direct, limited aeration of methanogenic FBRs is described as a method for increased COD removal when treating highCOD, high‐sulfate wastewater
Quantification of Synthetic Organic Chemicals in Biological Treatment Process Effluent Using Solid‐Phase Microextraction and Gas Chromatography
Authors: Magbanua Benjamin S. , Mitchell Dennis R. , Fehniger Steven M. , Bowyer Rebecca L. , Grady C.P. Leslie
Published: October 2006

Solid‐phase microextraction (SPME), a technique that uses a polymer‐coated, fused‐silica fiber to selectively extract organic analytes from a sample matrix, followed by gas chromatography (GC), was used to quantify selected synthetic organic chemicals (SOCs) in biological reactor effluent. By selecting an appropriate combination of SPME fiber, GC column, and GC detector, assays to quantify either a suite of SOCs or single selected SOCs were developed. Phenol, 4chlorophenol, 2‐nitrophenol, 4‐nitrophenol, 2,4,‐dinitrophenol, isophorone, m‐toluate, m‐xylene, and di‐n‐butylphthalate were quantified simultaneously using an 85‐ m polyacrylate SPME fiber, a 5% diphenyl–95% dimethyl polysiloxane capillary column, and a flame ionization detector. m‐Xylene was quantified using a 100‐ m polydimethylsiloxane SPME fiber, a 5% diphenyl–95% dimethyl polysiloxane capillary column, and a mass spectrometric detector. Dichloromethane was quantified using an 85‐ m polyacrylate SPME fiber, a Carbopack B/1% SP‐1000 packed column, and an electron capture detector. All three assays enabled detection of the target analytes to low concentrations (g/L) with minimal sample volume and processing requirements.
Biological Augmentation Eliminates Grease and Oil in Bakery Wastewater
Authors: Keenan Daniel , Sabelnikov Alexander
Published: October 2006

The feasibility of a biological augmentation approach to eliminate oil and grease in the wastewater of a large bakery was evaluated and experimentally tested. The approach, based on approximation of a treatment tank with a model of a continuous culture of bacteria (chemostat), was evaluated first. Bacteria appropriate for use in biological augmentation were selected according to theoretical requirements. Results of subsequent field tests corresponded fairly well to predicted values, although oil and grease content in the outflow was still greater than the allowable level. To further increase cell concentration in the treatment tank, a solid support for bacterial growth, a biological filter, was added next and was successful. As a result, a bioremediation scheme was devised that included pH adjustment and mixing–aeration systems, an external biological reactor system for production and periodic injection of the appropriate bacteria to the treatment tank, and a biological filter. A dramatic reduction of oil and grease in the bakery waste from approximately 1.5 g/L to less than 0.03 g/L, which is three times less than accepted regulatory limits, resulted. Reliable functioning of the bioremediation system has been observed during an extended period of time (20 months).
Effects of Oxygen Supply Methods on the Performance of a Sequencing Batch Reactor for High Ammonium Nitrification
Authors: Dangcong Peng , Bernet Nicolas , Delgenes Jean‐Philipe , Moletta Rene
Published: October 2006

High ammonium nitrification was studied in a sequencing batch reactor (SBR) with two different oxygen supply methods: controlled oxygen supply rates (dissolved oxygen [DO] in the reactor controlled between 2 and 3 mg/L) and uncontrolled oxygen supply rates (DO in the reactor uncontrolled and changed ambiently with oxygen use rate). Experimental results showed that oxygen supply methods have significant effects on SBR performance for high ammonium nitrification. With the controlled oxygen supply method, ammonium and nitrite oxidations took place simultaneously. With the uncontrolled oxygen supply method, ammonium oxidation proceeded smoothly during the low DO period of a cycle; however, nitrite oxidation was at first completely inhibited at low‐DO but recovered during the high DO period of the same cycle. Ammonium and nitrite were oxidized sequentially during a cycle in SBR. Ammonium oxidizers developed an ability to endure the fluctuation of DO, but nitrite oxidizers did not. Extensive starvation under high DO concentrations plays an important role in ammonium oxidation under low DO conditions.
Biotic and Abiotic Features of a Deep Wastewater Treatment Lagoon Used for Agricultural Irrigation
Authors: Arauzo M.
Published: October 2006

The purpose of this investigation was to gain information about the dynamics of a deep wastewater treatment lagoon. The experimental lagoon was fed with secondary effluent from a municipal wastewater treatment plant. Biotic and abiotic profiles were recorded throughout the water column between July 1996 and December 1997. Influent and effluent were also sampled. Stable thermal stratifications were produced during the summer, reductions in sanitary indicators were observed, and the best results were obtained during the mixing period. Decreases in total nitrogen levels were also observed, with best results obtained during the stratification period. Conductivity showed no great seasonal variations, with only a slight increase in effluent conductivity. At no time was its level beyond the usual range in agricultural irrigation (0 to 3000 S/cm).
High‐Performance, Low‐Cost Solar Collectors for Disinfection of Contaminated Water
Authors: Vidal A. , Díaz A.I.
Published: October 2006

Although the germicidal action of sunlight has long been recognized, its potential for practical applications has to be researched more thoroughly. This paper summarizes the progress made toward a commercially practical collector for solar disinfection applications. Nontracking compound parabolic collectors (CPCs), developed originally for capturing solar photons for thermal energy applications, were examined as potential solar photoreactors. A field demonstration of solar disinfection treatment using commercially manufactured solar reactors was conducted. Field tests showed successful destruction of Escherichia coli and Enterococcus faecalis and have provided data for full‐scale design of water treatment systems. From above observations, a throughput value of 50 L/m2h for the low‐cost CPC reactor tested was estimated. For a 190 m3/d (0.05 MGD) facility, the estimated total costs for disinfection using UV‐A is U.S. .19/m3 (.70/1000 gal). The use of near‐UV sunlight to disinfect water supplies seems promising in rural communities of developing countries where treated water is unavailable.
Molecular Size Distributions of Dissolved Organic Matter in Wastewater Transformed by Treatment in a Full‐Scale Trickling Filter
Authors: Logan Bruce E. , Wagenseller Gretchen A.
Published: October 2006

The performance of biofilm reactors is primarily limited by the rate of diffusion of biodegradable molecules into the biofilm. Wastewater entering and leaving a trickling filter was therefore separated into three molecular weight size fractions of <1000 daltons (<1K), 1 to 10K, and >10K to <0.45 μm, and the concentration of 5‐day soluble biochemical oxygen demand (sBOD5) and dissolved organic carbon (DOC) were measured for each size fraction. On average, a large percentage of both the sBOD5 (82%) and DOC (78%) was contained in the smallest size fraction (<1K). Removal rates of sBOD5 were high. Influent sBOD5 values were reduced from 27.3 to 33.3 mg/L to 4 mg/L in the effluent. A comparison of a trickling filter model (TRIFIL2) indicated that removal rates of sBOD5 were much greater at this site than was typical of other trickling filters treating domestic wastewater. The large concentration of this small molecular weight fraction was believed to account for greater than normal removal rates. To demonstrate this, the molecular size distributions assumed in the trickling filter model TRIFIL2 were adjusted to fit the measured size distributions. The measured average removal of 92% compared well to the 93% removal predicted by the TRIFIL2 model with these measured molecular size distributions. These measurements and model simulations demonstrate that the performance of trickling filters can be linked directly to physical characteristics of the wastewater such as the molecular size distribution of biodegradable organic matter.
Effects of a Waste Stabilization Lagoon Discharge on Bacterial and Phytoplanktonic Communities of a Stream
Authors: Masseret Estelle , Amblard Christian , Bourdier Gilles , Sargos Denis
Published: October 2006

To determine the effect of a waste stabilization lagoon discharge on the plankton in a receiving stream, bacterial and phytoplanktonic communities were studied above and below the outflow. The discharge apparently had seasonal and continuous effects on both the structure and function of plankton communities. These effects below the lagoon resulted in a significant increase in the bacterial and phytoplanktonic biomasses and significant changes in the structure of these communities: increases of Euchlorophyceae (Chlorella and Scenedesmus), Euglenophyceae (Trachelomonas), Cyanobacteria biomasses, and the relative biomass of very large bacteria. Metabolic activities of the plankton communities seemed to be significantly influenced; photosynthetic and heterotrophic activities increased, while productivity (photosynthetic assimilation and chlorophyll a) decreased. This decrease shows that allochthonous phytoplankton photosynthetic efficiency is lower than that of the autochthonous community or that this efficiency is reduced in the receiving stream. Discharge favored the development of mixotrophic microorganisms to the detriment of photosynthetic microorganisms.
Performance of a Constructed Wetlands in Treating Urban Stormwater Runoff
Authors: Carleton James N. , Grizzard Thomas J. , Godrej Adil N. , Post Harold E. , Lampe Les , Kenel Pamela P.
Published: October 2006

An investigation was conducted on the pollutant removal performance of a constructed wetlands treating stormwater runoff from a residential townhome complex in northern Virginia. Constituent event mean concentrations for 33 runoff events between April 1996 and May 1997 were measured based on flow‐weighted composite samples collected at the facility's inlet and outlet. With the results from a limited number of grab samples representing ungauged overland drainage from an adjacent wooded area, estimated removals were positive for most constituents and typically exceeded those obtained at a nearby companion wetland study site, consistent with expectations based on the relative ratios of wetland area to drainage area at the two sites. Median load removals of all constituents were greater for a subset of 22 storms that had inflow volumes less than the maximum volume of the marsh. Orthophosphate phosphorus and ammonia removals were significantly better during spring of 1996 than spring of 1997. Lysimeter data suggest a possible explanation for this, which is development of anaerobic conditions in the shallow sediments in 1997. Outlet concentrations of oxidized nitrogen were consistently lower in base flow than in storm samples, suggesting that removal of this constituent occurred primarily between, rather than during, storm events.
Phytoremediation of 1,4‐Dioxane by Hybrid Poplar Trees
Authors: Aitchison Eric W. , Kelley Sara L. , Alvarez Pedro J.J. , Schnoor Jerald L.
Published: October 2006

1,4‐Dioxane (dioxane), a suspected carcinogen, is a persistent environmental pollutant that is difficult to remove from contaminated sites. This work investigated the feasibility of vegetative uptake as a site remediation alternative. In hydroponic studies, hybrid poplar cuttings (Populus deltoides × nigra, DN 34, Imperial Carolina) removed 23 mg/L dioxane rapidly. Within 9 days, a removal of 54.0 ± 19.0% was achieved. This removal corresponded to a transpiration stream concentration factor of 0.72 ± 0.07. Poplars also effectively remediated a dioxane‐spiked soil (10 mg/kg). Only 18.8 ± 7.9% of the initial dioxane spike remained in planted soil after 15 days, compared with 72.0 ± 7.7% remaining in sterilized, unplanted soil. In both hydroponic and soil experiments, 76 to 83% of the dioxane taken up by poplars was transpired from leaf surfaces to the atmosphere, where it can be readily dispersed and photodegraded. These results suggest that phytoremediation is a viable alternative to remove dioxane from contaminated sites and should be considered for other hydrophilic contaminants.
Applicability of Batch Test Data for Industrial Wastewater Continuous Flow Process Design
Authors: Argaman Yerachmiel , Raize Ofer , Eckenfelder W. Wesley , O'Reilly Alan J.
Published: October 2006

Kinetic data from batch tests were successfully used to predict the performance of continuously stirred tank reactor (CSTR) systems for treating multicomponent industrial wastewater. Data from both batch and continuous tests validated the multiple zero order (MZO) approach for evaluating CSTR systems and should prove valuable in designing full‐scale continuous flow treatment processes. Treatability studies were conducted on three industrial wastewaters and one synthetic wastewater. The MZO approach consistently predicted values for effluent concentrations in appreciably closer agreement with experimental results than those predicted by means of nth‐order true chemical reaction. Evaluating the continuous process should include a correction for biomass activity if the solids retention time (SRT) of the biomass in the CSTR is found to be appreciably different from that of the batch reactor. This correction is necessary to account for the effect of the change in biomass activity resulting from different SRT on the magnitude of the biodegradation rate coefficient.
Assessment of Aeration System Performance Efficiency: Frequent Sampling for Damage Detection
Authors: Iranpour R. , Magallanes A. , Zermeño M. , Moghaddam O. , Wilson J. , Stenstrom M.K.
Published: October 2006

A study of oxygen transfer efficiency (OTE) in aeration basins, using measurements of oxygen depletion in offgas collected from them, was carried out over a period of several years by collaborations between the University of California, Los Angeles and the Bureau of Sanitation Research Group of the City of Los Angeles. Measurements were taken of dissolved oxygen (DO), water temperature, oxygen depletion, and air flux at each sampling location as part of the process to obtain standardized OTE. Field instruments, permanently located near the tanks and galleries, are connected to the control room that automatically records return activated‐sludge flow, influent flow, tank DO sensor readings, and air flow. Data from the control room and field instruments were collected for the times of the samples to provide context and some degree of quality control for the samples obtained by the measurement team. The combined air flux and OTE measurements not only agree with the familiar inverse relationship between OTE and air flux but have allowed detection of strong evidence that serious leakage has developed in a few weeks in the air distribution systems of tanks 4 and 5, which was indirectly confirmed by observation of water ejection from the air release valves on the tanks. However, the detail provided by OTE measurements allows more specific understanding of the magnitude of the problem and its significance for the operation of these tanks. Analysis of the OTE measurements made at the site since 1991 also indicates that the diffusers in some of the tanks may now be in need of cleaning or replacement.
Gastight Sampler for Sequential Streamflow Sampling
Authors: Amundsen Eric L. , Pratt Jerry E. , Hemond Harold F.
Published: October 2006

The objective of this work was to design and construct an automatic gastight streamwater sampler capable of collecting samples during a 24‐hour period. To minimize cost and complexity, wetted glass syringes with narrow collection tubes were used as sample containers. The streamwater sampler prototype was tested in a stream that contained elevated levels of volatile organic compounds, and it worked satisfactorily under field conditions. Syringe collectors were a reliable and cost‐effective method of acquiring sequential gastight water samples.
Treatment of Trace Organic Compounds by Ozone–Biological Activated Carbon for Wastewater Reuse: The Lake Arrowhead Pilot Plant
Authors: Levine B.B. , Madireddi K. , Lazarova V. , Stenstrom M.K. , Suffet I.H.
Published: October 2006

Organic and trace organic performance data for preozonation and biological activated carbon (BAC) filtration of the Lake Arrowhead, California, water reclamation pilot plant secondary effluent were analyzed to determine treatment efficiency of these processes in a potable water reuse project. Five types of organic analysis were performed: dissolved organic carbon (DOC), UV at 254 nm (UV‐254), ultimate soluble biochemical oxygen demand (SBODU), baseneutral analysis (BNA), and specific aldehyde analyses. Preozonation favored the breakdown of high‐molecular‐weight organic matter (> 1000 daltons [Da]), measured as DOC, to biodegradable organic compounds, measured as an increase in SBODU. Also, a shift in mass concentration of BNAs from the higher scan index fraction (< 1000 Da) to the lower scan index fraction was shown by gas chromatography–mass spectrometry profile analysis. After preozonation, organic compounds were sorbed and biodegraded through the BAC filter. Steady state was reached for DOC and UV‐254 absorbance after 50 to 100 days. Trace organic compounds started breaking through the column 200 days after BAC startup. Breakthrough was not uniform for BNAs. Apparent differences between the lower and higher molecular weight fractions of BNAs were shown, indicating a greater breakthrough rate for the higher scan index fractions. Finally, lists of tentatively identified BNA compounds were created, highlighting the change in chemical composition of the base‐neutral fraction before and after each process.
Evaluation of Brine Inflow at a Waste Isolation Pilot Plant
Authors: Knowles M.K. , Economy K.M.
Published: October 2006

The Waste Isolation Pilot Plant (WIPP) is a mined, geologic repository operated for the U. S. Department of Energy in New Mexico. Ongoing technical programs at the facility support requirements regarding continued demonstration of compliance with regulations and improvements to operational efficiency. One factor that can be important to performance measurements at WIPP is the volume of fluid flowing into the repository. The objective of the analysis presented in this paper is to address those processes that influence liquid inflow to the waste disposal areas. Simulations focus on the coupling between brine inflow and properties of the proximal damaged zone in the host rock. Calculations show that significant reduction in predicted brine inflow results when two‐phase flow properties of the damaged zone are modified relative to baseline values. Results warrant further investigation regarding these properties. The study also indicates that only nominal improvement to predictive capabilities would result from using a fully coupled transient approach to simulate development of damage in the host rock.