bluuebunny/crossref_metadata_2025 huggingface dataset:
Estenose da fossa intercondilar após estabilização articular com retalho de fáscia lata em cães
Authors: Selmi André Luis , Padilha Filho João Guilherme , Lins Bruno Testoni , De Nardi Andrigo Barboza , Penteado Bianca Mota
Published: February 2012

Determinaram-se os índices de largura da fossa intercondilar (FI), após transecção do ligamento cruzado cranial em nove cães adultos submetidos à estabilização articular com retalho de fáscia lata. Os joelhos foram alocados em dois grupos, sendo o joelho direito (GI) submetido à incisuroplastia troclear (ITR) e posterior estabilização articular, e o joelho esquerdo submetido somente à substituição ligamentar (GC). Cada grupo foi dividido em três subgrupos correspondentes aos momentos de eutanásia aos 30, 90 e 180 dias de pós-operatório. Os índices de largura da FI foram determinados, macroscópica e radiograficamente, pela mensuração da abertura cranial da FI nos terços cranial, médio e caudal, e indexados em relação à largura epicondilar. Observou-se aumento significativo dos índices macroscópicos e radiográficos nas articulações do GI, sendo estes estatisticamente diferentes daqueles das articulações de GC. Não foi observada estenose intercondilar nos joelhos de GC após a estabilização articular. Conclui-se que a estabilização articular com retalho de fáscia lata preveniu a estenose da fossa intercondilar, e que a ITR promoveu o alargamento permanente dessa estrutura.
Restrição alimentar para suínos machos castrados e imunocastrados em terminação
Authors: Santos Alexandre Pereira dos , Kiefer Charles , Martins Leandro Pereira , Fantini Caiki Calepso
Published: February 2012

O objetivo do trabalho foi avaliar o desempenho e as características quantitativas de carcaça de suínos machos castrados e imunocastrados, sob alimentação à vontade ou restrição quantitativa. Foram utilizados 240 animais, com peso inicial de 91,49±3,26kg, distribuídos em delineamento experimental de blocos ao acaso, em esquema fatorial 2x2 (dois manejos alimentares e duas categorias), com quatro repetições e 15 suínos cada. Suínos sob restrição alimentar apresentaram consumo inferior (P<0,05) em relação aos alimentados à vontade. O consumo de ração não diferiu (P>0,05) entre castrados e imunocastrados. Suínos alimentados à vontade apresentaram maior (P<0,05) ganho de peso em relação àqueles sob restrição. Os imunocastrados apresentaram ganho de peso superior (P<0,05) aos castrados. Houve interação (P<0,05) entre manejo e categorias para conversão alimentar, em que a restrição melhorou a conversão alimentar dos castrados em relação aos imunocastrados. Além disso, os imunocastrados apresentaram melhor (P<0,05) conversão alimentar em relação aos castrados, independente do manejo alimentar. Não houve interação (P>0,05) entre os fatores sobre as características de carcaça. A restrição não afetou (P>0,05) as características de carcaça. Machos imunocastrados apresentaram menor (P<0,05) espessura de toucinho e maior percentual de carne magra na carcaça. A restrição alimentar melhora a conversão alimentar de machos castrados. A restrição alimentar piora o ganho de peso e não altera as características de carcaça dos machos castrados e imunocastrados. Suínos imunocastrados apresentam desempenho superior, menor espessura de toucinho e maior percentual de carne magra em relação aos castrados.
Linguiças frescais elaboradas com carne de avestruz: características físico-químicas
Authors: Nascimento Rafael Soares , Fonseca Ana Beatriz Monteiro , Franco Robson Maia , Miranda Zander Barreto
Published: February 2012

A carne de avestruz por apresentar baixos conteúdos de colesterol, gordura intramuscular e altas percentagens de ácidos graxos poli-insaturados ômega-3 é considerada uma carne vermelha saudável e de grande aceitação junto aos consumidores. Considerando que os recortes resultantes da desossa das carcaças de avestruz são partes consideradas menos nobres, desenvolveu-se a produção de três formulações de linguiça frescal tendo como base a carne de avestruz (recortes e aparas), promovendo as análises físico-químicas e colorimétricas com o objetivo caracterizar o perfil físico-químico e colorimétrico dessas diferentes formulações. As três formulações se encontraram dentro dos padrões físico-químicos estipulados pela legislação brasileira (BRASIL, 2000) e não apresentaram diferença significativa entre si, com exceção do teor de cinzas, mais alto nas linguiças mistas. Na análise do teor de pH, observou-se diferença significativa entre os tratamentos, com pH maior nas linguiças puras em relação às mistas. As linguiças puras foram mais escuras e vermelhas que as mistas, sendo que a mista de avestruz, suína e frango foi a mais clara. As linguiças frescais puras ou mistas elaboradas com carne de avestruz são uma opção viável de produção e comercialização, podendo concorrer no mercado com as linguiças tradicionais com perspectiva de êxito.
Amylose content in rice (Oryza sativa) affects performance, glycemic and lipidic metabolism in rats
Authors: Denardin Cristiane Casagrande , Boufleur Nardeli , Reckziegel Patrícia , Silva Leila Picolli da , Walter Melissa
Published: February 2012

This research aimed at evaluating the effect of diets with high, intermediate and low amylose content of rice on performance, glycemic and lipidic metabolism in rats. Male Wistar rats were fed diets with grains of cooked rice of the cultivars 'IRGA 417', 'IRGA 416' and 'MOCHI' with high, intermediate and low amylose content, respectively. Wet and dry fecal production and serum HDL cholesterol were not affected by amylose content. The animals in the treatments with high amylose content ('IRGA 417') presented lower feed intake, body weight gain and apparent digestibility, higher fecal water content and nitrogen excretion, reduced fecal pH, lower postprandial blood glucose response, serum total cholesterol and triglycerides levels and pancreas weight, and higher fasting serum glucose concentration and liver weight. Amylose:amylopectin ratio significantly affects rice starch digestion in the gastrointestinal tract, affecting some biologically relevant parameters.
Estabilidade química, físico-química e microbiológica de polpas de acerola pasteurizadas e não-pasteurizadas de cultivo orgânico
Authors: Lima Rafaela Maria Temóteo , Figueiredo Raimundo Wilane de , Maia Geraldo Arraes , Sousa Paulo Henrique Machado de , Figueiredo Evânia Altina Teixeira de , Rodrigues Cinthia Soares
Published: February 2012

O presente trabalho objetivou avaliar a estabilidade química, físico-química e microbiológica de polpas de acerola pasteurizadas e não-pasteurizadas, oriundas de cultivo orgânico e armazenadas sob congelamento (-18±2°C) durante 360 dias. O armazenamento sob congelamento não ocasionou perdas significativas de qualidade das polpas de acerola. No entanto, o tratamento térmico influenciou negativamente nos conteúdos iniciais de alguns componentes, principalmente sólidos solúveis, açúcares solúveis totais e redutores, que apresentaram conteúdos inferiores no início do armazenamento para as polpas pasteurizadas. As polpas pasteurizadas e não-pasteurizadas apresentaram boa qualidade microbiológica do início ao final do armazenamento. Dentre as polpas estudadas, as polpas não-pasteurizadas apresentaram melhores características iniciais de cor. As polpas pasteurizadas garantiram melhores características microbiológicas no que concerne aos aspectos de segurança alimentar.
A preliminary evaluation of shallow-water rhodolith beds in Bahia Magdalena, Mexico
Authors: Ávila Enrique , Riosmena-Rodriguez Rafael
Published: February 2012

The aim of the present study was to describe the structure of shallow-water rhodolith beds from Bahia Magdalena, one of the most productive estuarine systems of the Mexican Pacific coasts. From September 2008 to May 2009 four rhodolith beds were found (between 1 and 3 m depth) and population descriptors such as rhodolith density, size classes, branch density, volume and weight were determined. The dominant rhodolith forming species was Lithophyllum margaritae. The size of beds ranged from 7,600 to 17,800 m2 approximately with densities from 42.2 to 215.9 ind.m-2. In these beds, L. margaritae shows fruticose and foliose growth forms, from which spherical forms were predominant (81-99%). Branch density (from 3.0 to 13.3 branches.cm-2) varied significantly (p < 0.05) among beds. The average volume (from 2.0 to 400 mL) and wet weight (from 32.4 to 84.8 g) was not significantly different among sites, but a significant positive correlation (r = 0.95, p < 0.05) was found between these parameters. The size of plants ranged from 2.0 to 11.5 cm with predominant size classes of 40.1-60 mm. Differences in rhodolith density, branch density and sphericity were attributed to possible differences in hydrodynamic conditions among sites. These beds were also a suitable habitat for high diversity of associated sponges. A non-metric multidimensional scaling (MDS) analysis using sponge species data revealed variability in the distribution of sponge assemblages among sites, which is likely the result of differences in environmental conditions. Although these rhodolith beds are not as extensive as those of other regions, our preliminary surveys revealed that they are a common habitat in Bahía Magdalena and likely have an important role in the productivity of this estuarine system.
Dynamic stability of geosynthetic-reinforced soil integral bridge
Authors: Munoz H. , Tatsuoka F. , Hirakawa D. , Nishikiori H. , Soma R. , Tateyama M. , Watanabe K.
Published: February 2012

ABSTRACT: To evaluate the dynamic stability of different bridge types, the results from a series of shaking-table tests on small-scale models of the following bridge types were analysed within the framework of the single-degree-of-freedom theory: (1) a conventional bridge (CB), comprising a girder (i.e. deck) supported via a pair of movable and fixed bearings (i.e. shoes) by gravity-type abutments (without a pile foundation) having unreinforced backfill; (2) a GRS-RW bridge, comprising a girder supported via a pair of movable and fixed bearings by a pair of sill beams placed on the crest of a pair of geosynthetic-reinforced soil-retaining walls (GRS-RWs) having a stage-constructed full-height rigid facing; (3) an integral bridge (IB), comprising a girder integrated to a pair of abutments (without bearings) and unreinforced backfill; (4) a GRS integral bridge, comprising a girder integrated to the abutments (in the same way as the IB bridge) while the backfill is reinforced with geosynthetic layers connected to the facings (in the same way as the GRS-RW bridge); and (5) a GRS integral bridge with a cement-mixed soil zone of rectangular prismatic or trapezoidal shape immediately behind the facing. The following is shown: the stability of the bridge against dynamic excitations increases: (1) with an increase in the initial natural frequency via an increase in the initial stiffness; (2) with a decrease in the decreasing rate of stiffness during cyclic loading (i.e. an increase in the dynamic ductility); (3) with an increase in the damping energy dissipation capacity near and at failure; and (4) with an increase in the dynamic strength. With the GRS integral bridge, the structural integration and geosynthetic-reinforcing of the backfill, as well as cement-mixing of the backfill immediately behind the facings, all contribute to the evolution of these four factors. The natural frequency can then always be kept much higher than the predominant frequency of ordinary design earthquake motion, the response acceleration is kept sufficiently low, and the dynamic stability can be kept very high.
Real-time full matrix capture + total focusing and other novel imaging options using general purpose PC-based array instrumentation
Authors: Lines D I A , Wharrie J , Hottenroth J
Published: February 2012

Data acquisition using full matrix capture (FMC) and image reconstruction by the total focusing method (TFM) offers many benefits over conventional ultrasonic array beamforming techniques. These include dynamic focus on both transmit and receive for enhanced resolution and the ability
to alter the focus and steer angle without re-scanning. However, the technique has remained in the laboratory because of the costs associated with acquiring many channels in parallel and the absence of a real-time reconstruction capability. This paper describes a solution to these constraints.
The paper reviews the issues limiting the current implementations and describes how they were overcome by using flexible and scalable PC-based hardware modules. This new architecture already achieves acquisition and processing at 20 Hz and higher, meeting the requirements for interactive scanning
and so enabling these techniques to transfer from the laboratory into the field. Results from the first phase of a continuing investigation are presented. New application approaches, where these techniques offer particular benefits over conventional techniques, are discussed.
Predictors of Victim–Perpetrator Relationship Stability Following a Sexual Assault: A Brief Report
Authors: Edwards Katie M. , Kearns Megan C. , Gidycz Christine A. , Calhoun Karen S.
Published: February 2012

The researchers assessed the predictors of victim–perpetrator relationship stability following a sexual assault. Participants included 254 women sexually assaulted by a friend, casual dating partner, or steady dating partner. Results suggested that most victim–perpetrator relationships (75%) continued following the sexual assault. Greater trauma symptomatology, less perpetrator blame, and nondisclosure of the assault by victims predicted relationship continuation with the perpetrator. Additionally, the odds of continuing the relationship were greater following acts of sexual coercion than following acts of completed rape. Close relationships (steady dating partner) were more likely to continue following the sexual assault than less close relationships (friends and casual dating partners). Unexpectedly, the odds of relationship stability were greater for women without histories of childhood sexual abuse than women with histories of childhood sexual abuse. Implications for future research and intervention are discussed.
Clinical Postconference Pedagogy: Exploring Evidence-Based Practice with Millennial-Inspired “Building Blocks”
Authors: Schams Kristin A. , Kuennen Jackie K.
Published: February 2012

This article reports an innovative teaching strategy consisting of learning units whereby students come to postconference sessions prepared to share evidence-based practice (EBP) information associated with upcoming laboratory concepts, discover relationships among laboratory concepts and current nursing practice, and associate personal clinical experiences with the practice environment. This strategy, named “Building Blocks,” represents one method to transform nursing education into a more active process, and also has the potential to prepare graduates who can function in a dynamic health care environment incorporating EBP.
Hydraulic Fracture Crossing Natural Fracture at Nonorthogonal Angles: A Criterion and Its Validation
Authors: Gu H.. , Weng X.. , Lund J.. , Mack M.. , Ganguly U.. , Suarez-Rivera R..
Published: February 2012

Hydraulic-fracturing treatments have become an indispensable part of well completion in shale gasfield development. Shale formations often contain natural fractures, and complex hydraulic-fracture networks may form during a treatment. The complex fracture network is strongly influenced by the interaction between the hydraulic fracture and the pre-existing natural fractures. A criterion has been developed to determine whether a fracture crosses a frictional interface (pre-existing fracture) at nonorthogonal angles. This criterion is an extension of the one for orthogonal crossing originally developed by Renshaw and Pollard (1995). The dependence of crossing on the intersection angle is shown quantitatively using the extended criterion. The fracture is more likely to turn and propagate along the interface than to cross it when the angle is less than 90°. The validation of the criterion using laboratory experiments for various angles is described and discussed. When applied to laboratory experiments, good agreement between the criterion and experiments is observed for a wide range of angles. The criterion can be used to determine whether hydraulic fractures cross natural fractures under particular field conditions, and it has been incorporated in a hydraulic-fracture model that simulates hydraulic-fracture propagation in a naturally fractured formation.
Effect of Ti on the Mechanical Properties and Corrosion of Cast AZ91 Magnesium Alloy
Authors: Ai Xiulan , Quan Gaofeng
Published: February 2012

Ti addition to AZ91 alloy was been investigated with conventional casting. The microstructure and mechanical
property were examined. The Corrosion resistance of all the different Ti addition content alloy was studied in 3.5% NaCl
solution through weight loss measurement in constant immersion conditions and potentiodynamic polarization
experiments. The results show that addition of Ti with an amount of 0.1~0.5%wt resulted in a refinement of the as-cast
microstructure. The morphology of β phases is changed from coarse, uneven, semi-continuous skeletal network to small,
uniform, short rod-like or granular. When the content of Ti is 0.4wt%, the tensile strength and elongation go up to
maximum value of 197 MPa and 6.9% respectively. The corrosion resistant improved through addition Ti element is
related to the morphology and distribute of β phases. The mechanism of mechanical properties and corrosion resistant
improvement caused by Ti addition is discussed.
Odor control research at the Montgomery County Regional Composting Facility
Authors: Hentz Lawrence H. , Murray Charles M. , Thompson Joel L. , Gasner Larry L. , Dunson James B.
Published: February 2012

ABSTRACT:  Odor control has been an important component of the operation of the Montgomery County Regional Composting Facility. After several facility improvements, which greatly reduced off‐site odors, the discharge of compost process air remained the greatest source of odor impacts on the surrounding community. Thus, the WSSC assembled a research team to investigate methods of improving odor control treatment for the process air. The research team developed bench‐scale tests and gas chromatographic methods that provided a better understanding of the chemical basis for odor control. Organic sulfur‐containing compounds, especially dimethyl disulfide, were identified as the primary odorants in the process air. Effective removal of the reduced organic sulfides requires oxidation by sodium hypochlorite at a neutral pH. Ammonia interferes with this oxidation process and must be removed to allow effective and reliable oxidation. Hydrogen peroxide has also been used to improve oxidation and reduce chlorine odors. The removal of organic compounds has been enhanced by the use of surfactants. These findings have resulted in further full‐scale improvements to the existing compost process air scrubbing system.
Bench‐scale removal of odor and volatile organic compounds at a composting facility
Authors: Van Durme Gayle P. , McNamara Brian F. , McGinley Charles M.
Published: February 2012

ABSTRACT:  VOC emissions from an aerated static pile composting operation are identified and quantified. The most significant odorous VOCs are dimethyl disulfide, dimethyl sulfide, limonene, and alpha‐pinene. A comparison of data from several compost facilities reveals that these compounds are typical but tend to occur in higher concentrations when raw sludge is composted. Active compost exhaust treatment was investigated by bench‐scale testing a packed tower scrubber with various chemicals and three types of adsorbent media. Scrubbing chemicals included sulfuric acid, sodium hydroxide, sodium hypochlorite, hydrogen peroxide, potassium permanganate, DeAmine (by Nutech), and a surfactant. Adsorbent media included virgin activated carbon, caustic impregnated carbon, and a biofilter composed of finished compost. The best results were obtained with a two‐stage packed tower scrubber using acid in stage 1, followed by caustic and hypochlorite at pH 10 in stage 2.
Process control factors influencing Nocardia populations in activated sludge
Authors: Cha Daniel K. , Jenkins David , Lewis William P. , Kido Wendell H.
Published: February 2012

ABSTRACT:  Bench‐scale activated sludge experiments were conducted on Sacramento, California, primary effluent to determine the effect of various process control factors on Nocardia populations in activated sludge. It was possible to wash Nocardia out from activated sludge at a sufficiently low MCRT. The washout MCRT for bench‐and full‐scale activated sludge plants was related to the temperature by the Arrhenius equation. Foam trapping was shown to be a major factor in increasing Nocardia populations in activated sludge. The optimum pH for Nocardia growth in activated sludge was approximately 6.5. Aerobic selectors were effective in controlling Nocardia at an MCRT of 5 days but not at an MCRT of 10 days. Anoxic selectors controlled Nocardia in a nitrifying activated sludge at an MCRT of 12 days.
Model for predicting PCE desorption from contaminated soils
Authors: Biswas Nihar , Zytner Richard G. , Bewtra Jatinder K.
Published: February 2012

ABSTRACT:  A mathematical model has been developed to assist in the evaluation of remediation options in case of a spill of volatile organic compounds, such as perchloroethylene (PCE), in a soil environment. This model has been verified to predict the adsorption, desorption, and leaching of PCE from four types of soil and adsorption media. Freundlich isotherm adsorption coefficients are used in the model. Using the mathematical model, typical nomographs for PCE have also been developed. These nomographs can be used to evaluate leaching of PCE with water as a remediation option in given contaminated soils. Application of the model is presented with an example. The generalized model can also be used for compounds similar to PCE in other soil environments provided that Freundlich isotherm adsorption constants for the particular chemical and the specific soil characteristics have been determined.
Effect of measurement error of settling velocity on secondary sedimentation tank design
Authors: Ong S. L.
Published: February 2012

ABSTRACT:  A simple nonlinear regression technique is presented for obtaining the equation of settling velocity as a function of sludge concentration based on the data obtained from multiple batch settling tests. The equation obtained is incorporated into a computer procedure for sizing a secondary sedimentation tank. The proposed procedure is used for assessing the effect of measurement error associated with the settling velocity on the design of a secondary sedimentation tank through Monte Carlo simulation. The results obtained indicate that the mean of absolute percentage error associated with the limiting solids flux capacity of a secondary sedimentation tank varies almost linearly with the level of measurement error associated with the settling velocity. It is also observed that the required clarification area can be estimated more accurately than the required thickening area. It is further noted that a better estimate of thickening area can be obtained when the desired underflow solids concentration is chosen at a lower level.
Priority pollutant loads from effluent discharges to the San Francisco Estuary
Authors: Davis Jay A. , Gunther Andrew J. , O'Connor Joseph M.
Published: February 2012

ABSTRACT:  Effluent monitoring data collected under the National Pollutant Discharge Elimination System (NPDES) Program were used to estimate pollutant loads from effluent discharges to the San Francisco Estuary for the period of 1984–1987. Most analyses of priority pollutant concentrations in effluents yielded “below detection limit” (BDL) results. Although many pollutants were monitored in effluents, quantitative assessment of spatial and temporal trends in loads could only be performed for four pollutants (chromium, copper, nickel, and zinc) that were detected in more than 50% of analyses. Four municipal wastewater treatment facilities accounted for approximately 50% of the total loads of these elements to the Estuary. Statistically significant declines in loads from some of the largest dischargers were observed. Modifications to procedures for collecting and reporting effluent monitoring data that would enhance the value of these data in assessments of mass loading include the use of more sensitive analytical methods for pollutants of greatest concern, increased sampling frequency for large discharges, routine reporting of B D L results in their uncensored form, and comprehensive reporting of quality assurance data.
Sludge quality benefits realized from drinking water stabilization
Authors: Kuchenrither Richard D. , Elmund G. Keith , Houck Carl P.
Published: February 2012

ABSTRACT:  Concerns about sludge quality continue to increase as emphasis shifts from disposal to use. A frequently asked question is what effect a drinking water stabilization program will have on the metal content of wastewater sludge. Data presented in this paper clearly show that there is a direct correlation between drinking water corrosivity and some metal contents of sludge. Further, if the potential side effects of a drinking water stabilization program are acceptable, the metals concentration in the sludges can be reduced significantly, which may make beneficial use a viable alternative.
Aerobic treatment of metal‐cuttingfluid wastewater
Authors: Kim Byung R. , Anderson Stanley G. , Zemla Jerome F.
Published: February 2012

ABSTRACT:  Two separate sets of aerobic treatment experiments were conducted using two‐stage chemostats. The first set involved the aerobic treatment of effluent collected from the anaerobic reactor, which was treating a simulated metal‐cutting‐fluid wastewater (anaerobic/aerobic treatment), while the second set involved the straight aerobic treatment of the wastewater (straight aerobic treatment). Both anaerobic and aerobic experiments were conducted such that practically all biodegradable organics in either anaerobic or aerobic environment were degraded. Experimental results on the reduction of chemical oxygen demand (COD) indicated the following: (1) the anaerobic/aerobic treatment reduced the COD in the simulated wastewater by a total of 88%, 65% anaerobically, and 23% aerobically and (2) the straight aerobic treatment also reduced the COD in the simulated wastewater by 88%. Although both treatment schemes showed the same COD reduction, it is not known whether the organic compositions of the effluents are similar. Results also revealed that almost all of the organic nitrogen in the simulated wastewater was also degraded, indicating that nitrogen‐containing organic compounds in the wastewater such as alkanolamines and amino acids were biodegradable either anaerobically or aerobically.
Anaerobic removal of COD in metal‐cutting‐fluid wastewater
Authors: Kim Byung R. , Zemla Jerome F. , Anderson Stanley G. , Stroup David P. , Rai Devi N.
Published: February 2012

ABSTRACT:  The treatment of metal‐cutting‐fluid wastewater was investigated using an anaerobic, granular activated carbon, fluidized‐bed process. During 900 days of operation, three influent COD concentrations were tested: 1029, 3343, and 5324 mg/L. For each influent COD concentration, a series of influent flow rates was used to test a range of unexpanded empty‐bed contact times from 0.9 to 7.5 hours. The findings include the following: (1) the reactor removed biodegradable COD effectively and efficiently at relatively high loading rates (more than 70 kg/m3 · d); (2) approximately 35% of the influent COD was nonbiodegradable—more than approximately 65% of the nonbiodegradable COD was aerobically biodegradable; (3) approximately 68% of the COD biodegraded was converted to methane, showing potential for energy recovery; (4) a relatively low biomass production (a yield coefficient of approximately 0.09 g biomass produced/g COD degraded) was observed; and (5) the overall removal rate of biodegradable COD followed firstorder kinetics.
Biokinetic modeling and scale‐up considerations for rotating biological contactors
Authors: Spengel Douglas B. , Dzombak David A.
Published: February 2012

ABSTRACT:  Available growth kinetic models and a combined growth kinetic and mass transport model were applied to describe the performance of bench‐scale rotating biological contactors (RBCs) in treating low‐BOD, high‐ammonia landfill leachate. The growth kinetic models could describe the observed organic carbon and ammonia removals individually, but as currently formulated they are not capable of describing the simultaneous removal of multiple substrates. Moreover, these models assume that substrate removal is not oxygen limited, an assumption that renders them of little use for prediction of substrate removal under high loading conditions where oxygen deficiency may occur. Such conditions occurred in the first stages of the bench‐scale RBC units as has been observed at full‐scale in various wastewater treatment applications. To examine the effect of oxygen transfer on the simultaneous removal of organic carbon and ammonia, a combined growth kinetic and mass transport model, RBC Sector, was developed. RBC Sector described successfully the observed substrate removal rates and was useful in identifying the tank dissolved oxygen concentration (1.8 mg/L) at which RBC performance started to decline as a result of oxygen limitation. Because RBC Sector can predict the simultaneous removal of multiple substrates under oxygen‐limiting conditions, it is potentially useful as a scale‐up tool. Investigation of a key scale‐up issue, namely the radial variation of biomass thickness and density, would improve the utility of the model for scale‐up.
Thermal pretreatment of concentrated distillery spent wash
Authors: Lele Smita S. , Shirgaonkar Irfan Z. , Joshi Jyeshtharaj B.
Published: February 2012

ABSTRACT:  A novel thermal pretreatment reported earlier was employed to treat concentrated distillery spent wash to reduce the quantity to be handled at high pressure and high temperature involved in the proposed process. Three types of concentrated wastes, namely, high molecular weight high COD fraction obtained after membrane filtration of distillery waste, concentrated wastes obtained from distillery employing indirect heating, and concentration by partial evaporation of spent wash under vacuum, were studied to establish suitability of the proposed process for concentrated wastes. Thermal pretreatment at 230°C for 2 hours resulted in formation of charred residue having properties like lignite coal. The reduction in COD of the liquid phase was due to the separation of residue. Effect of dilution by treated waste on pretreatment was studied to estimate backmixing effect. Attempts were made to evaluate performance of different concentrated wastes in terms of extent of COD reduction, net energy recovery, and biodegradability. Other operational parameters, such as filterability, total pressure, and ease of handling of residue, were also evaluated. Thermal pretreatment of membrane‐filtered, concentrated fraction appeared to be promising.
Evaluation of oxygen transfer efficiency and alpha‐factor on a variety of diffused aeration systems
Authors: Groves Kathy Powell , Daigger Glen T. , Simpkin Thomas J. , Redmon David T. , Ewing Lloyd
Published: February 2012

ABSTRACT:  Because the aeration system in an activated sludge wastewater treatment plant typically represents more than 50% of total plant energy requirements, designers and operators can substantially reduce overall plant energy costs by using accurate oxygen transfer information to make the aeration system as energy efficient as possible. This paper presents data from 65 off‐gas analysis tests performed at 21 wastewater treatment plants. The effect of various factors on oxygen transfer was evaluated by comparing pairs of tests in which all factors but one were held relatively constant. Factors evaluated were diffuser type, diffuser layout, diffuser age, solids retention time, and level of nitrification. Flexible membrane diffusers had more than a 30% higher oxygen transfer efficiency than coarse bubble diffusers. Grid layouts had higher oxygen transfer efficiencies than spiral roll layouts. Flexible membrane diffusers that were 3.5 years old had a 20% lower oxygen transfer efficiency than new flexible membrane diffusers. Systems at low solids retention times that were not nitrifying had lower oxygen transfer efficiencies than nitrifying systems at high solids retention times. For some wastewater systems, use of this information on solids retention time in plant design and operation can decrease overall energy costs despite the additional oxygen required to meet the nitrogenous oxygen demand.
Quantification of wastewater odors by the affected public
Authors: Aitken Michael D. , Okun Melva F.
Published: February 2012

ABSTRACT:  Odors associated with wastewater collection and treatment are a common problem. Wastewater odors are difficult to quantify, and current methods of quantification are too cumbersome to permit long‐term evaluation of odor problems. In this project, residents in affected neighborhoods near a treatment plant in Winston‐Salem, North Carolina quantified odors by completing numerical odor rating forms three times a day for six months. The resulting database was used to evaluate the correlation of odors to a variety of factors. Residents from the same neighborhood had a high level of agreement in quantifying odors, and most participants had a reasonable ability to make distinctions among different degrees of odor. Odors correlated well with wastewater characteristics (for example, influent COD) and wind direction, implicating the treatment plant as the major source of odors in affected neighborhoods. Use of the numerical odor rating form was an effective and inexpensive means of quantifying wastewater odors, and in conjunction with other information gave a better picture of specific major sources of odor at the treatment plant.
Methanotrophic bacteria for nutrient removal from wastewater: attached film system
Authors: Jewell William J. , Nelson Yarrow M. , Wilson Mark S.
Published: February 2012

ABSTRACT:  It was hypothesized that nutrient removal from wastewater could be achieved by using methane oxidizing bacteria (methanotrophs). Because methane is inexpensive, it can be used as an energy source to encourage bacterial growth to assimilate nitrogen and phosphorus and other trace elements. This initial feasibility study used synthetic nutrient mixtures and secondary sewage effluent as feed to a laboratory‐scale methanotrophic attached‐film expanded bed (MAFEB) reactor operated at 35°C and 20°C. The MAFEB system operated successfully at low nutrient concentrations under a variety of nutrientlimited conditions. Using a synthetic nutrient mixture with a nitrogemphosphorus feed ratio(w/w) of 9:1, phosphate concentrations were reduced from 1.3 mg P/L to below 0.1 mg P/L, and ammonia was reduced from 12 mg N/L to approximately 1 mg N/L on a continuous flow basis, with a bed hydraulic retention time of 4.8 hours. The average nutrient uptake rates from synthetic nutrient mixtures were 100 mg nitrogen and 10 mg phosphorus/L of expanded bed/d. Nutrient assimilation rates increased with increasing growth rate and with increasing temperature. Nitrogen/ phosphorus uptake ratios varied from 8 to 13, and the observed yield varied from 0.11 to 0.16 g volatile solids (VS)/ g chemical oxygen demand (COD). Nutrient removal from secondary sewage effluent was successfully demonstrated using sewage effluent from two local treatment plants. Nutrient concentrations of 10‐15 mg N/L and 1.0‐1.8 mg P/L were reduced consistently below 1 mg N/L and 0.1 mg P/L. No supplemental nutrients were added to the sewage to attain these removal efficiencies since the nutrient mass ratios were similar to that required by the methanotrophs. Removal rates were lower at 20°C than at 35°C, but high removal efficiencies were maintained at both temperatures. Effluent suspended solids concentrations ranged from 8 to 30 mg volatile suspended solids (VSS)/L, and the effluent soluble COD concentration averaged 30 mg/L.
Biological treatment of kraft mill wastewater
Authors: Oleszkiewicz Jan A. , Trebacz Waclaw , Thompson Dave B.
Published: February 2012

ABSTRACT:  Wastewater from an integrated bleached kraft pulp and paper mill was treated in seven parallel treatment trains. Each train consisted of three reactors in series, with the primary reactor (denoted LI) simulating an aerated equalization/stabilization lagoon with hydraulic retention time (HRT) equal to 1.5 days. The secondary (middle) reactor was different in each train. Three reactors (Rl, R2, R3) were operated at HRT = 4.5 days and the solids retention time (SRT) equal to, respectively 10, 20, and 40 days. The next three secondary reactors (R4, R5, R6) were operated at HRT = 1.5 days and SRT equal to 10, 20, and 40 days, respectively. The secondary reactor in the seventh train (R7) was operated at an HRT equal to SRT set at 1.5 days, that is, effectively operating as an aerated lagoon. The last, third or tertiary reactor in each of the series was operated as a settling lagoon with all reactors (denoted El to E7) having identical HRT = 1.5 days. All seven treatment trains have removed 5‐day biochemical oxygen demand (BOD5) down to 10 mg/L. The removals of adsorbable organic halides (AOX) and soluble organic carbon (SOC) were found to be directly proportional to the biomass concentration and the SRT of the process and were the highest in the R6 reactor with SRT = 40 days and highest mixed liquor suspended solids (MLSS) of 3320 mg/L. In the activated sludge reactors Rl to R6 the removals of AOX and SOC were found to be inversely proportional to HRT, that is, the removals were larger for the reactors R4, R5, and R6 which operated at HRT =1.5 days. Overall AOX removal was the highest (30%) in the train LI → R6 → E6, and the lowest AOX removal (21%) was in the train of lagoons LI → R7 → E7. The negative effect of increased HRT on the removal of AOX and SOC was explained by biosorption since at the same SRT, the lower HRT reactors contained more than twice as much mixed liquor suspended solids.
Another look at thermophilic anaerobic digestion of wastewater sludge
Authors: Aitken Michael D. , Mullennix Robert W.
Published: February 2012

ABSTRACT:  New federal regulations on wastewater sludge management will be implemented in the near future and will have an impact on virtually every biosolids disposal method, including application to agricultural land. Current regulations on land application restrict land use according to the sludge treatment technology, whereas the new regulations will restrict land use based on pathogen destruction criteria. The most flexible land use practices will be allowed for biosolids with low pathogen content (Class A biosolids); for high‐temperature sludge treatment processes (greater than 53°C), indicator organism destruction can be used as a measure of pathogen destruction. The purpose of this study was to evaluate the indicator organism destruction capability of thermophilic anaerobic digestion. For the conditions studied, thermophilic digestion achieved the expected Class A limits on fecal coliforms; data are also presented on fecal streptococci destruction. Rapid startup of the thermophilic reactor (contrasting startup procedures used in the most recent full‐scale studies reported in the literature) and preliminary experiments on stability of the thermophilic population are described as well. Based on the results of this study, it appears that thermophilic anaerobic digestion can be a viable process for achieving Class A biosolids criteria.
Removal of copper (II) using vermiculite
Authors: Das Narayan C. , Bandyopadhyay Manas
Published: February 2012

ABSTRACT:  Copper(II) removal efficiency by vermiculite has been investigated through laboratory experiments. The removal phenomenon appears to be consistent with an ion‐exchange (exchange adsorption) process. The batch sorption equilibria follows Freundlich adsorption isotherm. The uptake of copper(II) is a function of the pH of the solution and increases with increasing pH. Increasing ionic strength and the presence of soluble complexing agents such as ethylene diamine tetraacetic acid (EDTA) decrease the sorption of copper (II). The presence of other divalent cations like calcium impede the uptake of copper (II). The presence of chloride ion has no significant effect on copper(II) removal. In a fixed bed vermiculite column, the removal efficiency of copper(II) from tap water is less than that from distilled water. Vermiculite can be regenerated with acid and can then be reused.
Inferred metal toxicity during the biotreatment of high ammonia landfill leachate
Authors: Manoharan Ramanathan , Harper Susan C. , Mavinic Donald S. , Randall Clifford W. , Wang Guoyao , Marickovich Donald C.
Published: February 2012

ABSTRACT:  Two nitrification‐denitrification systems were used to determine the possible inhibitory and/or toxic effects of supplementa metals addition to the nitrification‐denitrification process in the treatment of a relatively high ammonia, low biodegradable carbon, municipa landfill leachate. The addition of metals likely resulted in the precipitation of phosphorus which caused the nitrification‐denitrification process to be inhibited due to the deficiency of bioavailable phosphorus. Even though the phosphorus concentrations in mixed liquor and system effluent samples filtered through Whatman No. 4 filters or glass‐fiber filters appeared to be adequate, it was discovered that they were considerably lower when filtered through 0.45‐µm membrane filters. This seemed to indicate that although some of the precipitated phosphorus passed through the Whatman No. 4 filter, it was not available as a nutrient for microbial metabolism. Therefore, only the phosphorus that will pass through a 0.45‐µm membrane filter, and is defined as soluble in Standard Methods (1985) is readily available to the microorganisms. This should be monitored ensure sufficient nutrient availability in nitrification‐denitrification treatment systems potentially exposed to metals capable of precipitating phosphorus. It is recommended that a minimum soluble phosphorus concentration of 0.5 mg/L be maintained to ensure adequate phosphorus for nitrification and denitrification; in addition, when conducting activated sludge metal toxicity studies, total or Whatman No. 4‐filtered samples should not be used to determine the presence of adequate phosphorus.
Resuspension and clearing of dredge spoils after dredging, Cleveland Bay, Australia
Authors: Wolanski Eric , Gibbs Ronald
Published: February 2012

ABSTRACT:  During dredging operation, fine sediment is released in the navigation channel of the Port of Townsville, Australia, as a result of mechanical disturbance of the bed and of the overflow from the storage tanks of the dredger. Some of this sediment is advected away from the dredging site toward the beach and reef areas and could result in environmental damage if not managed properly. Field monitoring was conducted for salinity, temperature, suspended sediment, and acoustic profiles at several sites before and after dredging. Laboratory investigations on the effect of sediment concentration, turbulence, and floe size on the clearing of a suspension column were also undertaken. Results of both field and laboratory investigations show faster clearing in quiescent conditions than in turbulent conditions. Turbulence at low levels disturbs the dewatering microchannels of the fluid mud layer. As turbulence increases the effect of floe breakage and settling retardation also become important.
Dewatered sludge storage emissions control using multistage wet scrubbing
Authors: Sereno Douglas J. , McGinley Charles M. , Harrison David S. , Haug Roger T.
Published: February 2012

ABSTRACT:  The City of Los Angeles' Hyperion Treatment Plant is a 16.6 m3/s (380 mgd) municipal wastewater treatment plant with 8.8 m3/s (200 mgd) secondary treatment capacity. Digested sludge, mechanically dewatered by centrifuge, is stored as 20% solids wet cake in large storage bins. Previous studies identified the primary odorous constituents as dimethyl disulfide, dimethyl sulfide, and methyl mercaptan. Earlier pilot tests conducted at the plant indicated that activated carbon and dual‐media adsorption were not cost‐effective technologies for controlling the emission of odors, regulated volatile organic compounds (VOCs), and reactive organic gases (ROGs). An additional pilot test was therefore conducted to test multistage packed towers and various combinations of treatment chemicals. Scrubbing solutions tested included water, effluent, water with surfactants, sodium hypochlorite, sodium hydroxide, sulfuric acid, hydrogen peroxide, proprietary chemicals, and, as a polishing step, activated carbon. Chemical combinations were screened for effectiveness in a preliminary test phase using hand‐held instruments, gas chromatography, and dynamic olfactometry. Based on the results of these trials, more extensive testing was conducted. Analyses included gas chromatography–flame photometric detection (GC–FPD) for reduced sulfur compounds, and gas chromatography–mass spectrometry (GC–MS) for volatile organics. Two methods were used for reactive organics analyses. Total combustion analysis–flame‐ionization detection (TCA–FID), specified by the local regulatory agency was used, as well as nonmethane hydrocarbon approximations using GC. Results were encouraging for controlling wet cake storage odors with wet scrubbing. Removal efficiencies of up to 97% were encountered using a caustic/bleach scrubbing solution. The greatest ROG removal achieved was 89% using acid/bleach and peroxide. VOC removal, however, was poor for most combinations. VOC removal efficiencies ranging from 68 to 81% were recorded when carbon was used as a polishing step. The majority of removal occurred within the carbon stage, however, and not within the packed towers. It is expected that odors and ROGs can be controlled to acceptable levels using this multistage wet scrubbing approach. Additional studies are required to determine whether ROGs are oxidized or simply dissolved in the scrubbing liquid. Removal of VOCs was not encouraging and optimization of VOC removal needs to be investigated further.
Sludges from cold regions lagoons
Authors: Schneiter R. Wane , Middlebrooks E. Joe , Sletten Robert S. , Reed Sherwood C.
Published: February 2012

ABSTRACT:  Accumulated solids associated with the operation of aerated and facultative lagoons in cold climates were investigated to determine (1) the rate and extent of solids accumulation, (2) the characteristics of the accumulated solids, (3) the potential for in situ stabilization of the accumulated solids, and (4) the effect of lime treatment upon the pathogenic population and subsequent solids drying on sand and soil beds. Accumulated sludges from the Logan and Corinne, Utah, facultative lagoons and the Palmer and Galena, Alaska, partial‐mix aerated lagoons were studied. The rates of accumulation, determined by in situ measurement of the sludge layer in each lagoon, were found to vary with lagoon type and specific operational and environmental conditions. The solids characteristics, determined for samples upon collection and for samples in cold storage over time, were found to be generally comparable to those of conventional primary sludges. Sludge samples were stored for an extended period at temperatures that model winter conditions at the lagoon bottom and were periodically tested to determine if changes were occurring in basic sludge characteristics. With the exception of bacterial concentration reduction, no significant changes were observed, indicating that in situ stabilization of the sludge is probably not occurring in the actual lagoons under low‐temperature conditions. Lime treatment of the lagoon sludges was evaluated by dosing the sludges with lime and applying the limed sludges to bench‐scale sand and soil drying beds. Lime addition produced high pathogen kill levels. The limed sludges readily dewatered on both sand and soil beds.