bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical value of interwoven silver fibres in class II compression stockings: results from a crossover trial
Authors: Singer E , Thalhammer C , Degischer S , Aschwanden M , Labs K-H , Jaeger K A
Published: September 2006

Objective: The aim of the study was to show whether silver fibres interwoven into regular compression stockings will enhance the nutritive capillary perfusion in chronic venous insufficiency (CVI) patients.

Methods: Double-blind, randomized crossover trial with two 10-day treatment phases and an intermediate three-day wash-out in 20 CVI patients (7 males, 13 females, median age: 65 years), comparing regular and silver fibres containing class II compression stockings. Primary endpoint: tcpO2 measurement at 44°C probe temperature in the peri-malleolar region of the reference leg.

Results: In the overall study population, the 'end-of-treatment-phase' minus 'start-of-treatment-phase' tcpO2 – differences were negative for the regular hosiery (median [MAD]: -6.75 [8.5] mmHg, supine leg position; -7.25 [5.75] mmHg, dependent leg position), but positive for the silver fibre containing fabric (median [MAD]: 4.0 [7.75] and 2.5 [8.5] mmHg for the supine and the dependent leg position). The intergroup differences in the overall data were not statistically significant. Analysis of a core data-set, excluding data points above the 90% and below the 10% percentile, approached ( P = 0.052, supine) or reached statistical significance ( P = 0.023, dependent leg position).

Conclusions: The study provides first evidence that using interwoven silver fibres in class II compression stockings results in clinical benefit for CVI patients.
Safe introduction of the VNUS Closure procedure: a multidisciplinary approach
Authors: Mirza M S , Madill J , Parsons W , Gajraj H
Published: September 2006

Objectives: The National Institute for Health and Clinical Excellence supports the use of radiofrequency ablation (VNUS Closure) of the long saphenous vein (LSV) as an alternative to stripping. An increase in interest in the procedure is anticipated. The technique can produce serious complications not commonly associated with conventional surgery, and safety is a major concern with its introduction. The aim was to introduce the new technique into a district hospital, without major complications or failures.

Methods: A multidisciplinary team was developed consisting of consultant surgeon, vascular technologist and theatre nurse, who received intensive training and mentoring from a group with considerable experience. All members attended operating theatre and duplex imaging sessions over a period of six months. Approval for the introduction of the technique into our institution was sought from the Medical Director and Clinical Governance Directorate. The results of VNUS Closure surgery were included in the monthly clinical governance and audit meetings. During the consent process, the first patient was informed that the team had not yet undertaken the procedure, but had taken all necessary measures to ensure its competence. Subsequently, patients were advised of our experience and the results.

Results: Of the 18 patients who consented for the study, 13 (72%) were found on duplex scanning to have saphenofemoral reflux suitable for VNUS Closure. VNUS Closure was attempted in 22 LSVs in 13 patients; 21 LSVs (95%) in 12 patients were closed at surgery and 19 (86%) remained completely closed at a median of 12 months (range 3–24 months). There were no deaths and no major complications.

Conclusion: The safe introduction of VNUS Closure in a district hospital can be accomplished through intensive training and a process of mentoring from experienced practitioners, a multidisciplinary approach with a vascular technologist in theatre and attention to governance issues, in particular audit and consent.
Phlebography and heparin for deep venous thrombosis introduced by Gunnar Bauer more than 60 years ago
Authors: Thulesius Olav
Published: September 2006

The story of a surgeon who in a country hospital in Sweden became a pioneer of modern phebology. He helped to set the standard of venography and heparin treatment for deep venous thrombosis and post-thrombotic valvular insufficiency more than 60 years ago. This happened when the surgeon Gunnar Bauer, stimulated by advancement in research and development of anticoagulants, introduced heparin treatment for deep venous thrombosis. He also started using descending phlebography for detection of venous reflux and advocated the controversial method of early ambulation after deep venous thrombosis.
Primary and secondary lymphoedema in male patients with oedema in lower limbs
Authors: Bolcal C , Iyem H , Sargin M , Mataraci I , Doganci S , Kilic S , Karacalioglu O , Sahin M A , Demirkilic U , Tatar H
Published: September 2006

Objective: The purpose of this prospective study was to evaluate patients with clinically diagnosed lymphoedema of the lower extremities. The proportions of primary and secondary lymphoedema, the possible aetiologic factors and the concomitance of chronic venous diseases and lymphoedema were focused on.

Method: The male patients who attended our outpatient clinic during 2000 and 2004 were evaluated. In all, 160 male patients with 5 cm circumference difference at calf level between two lower extremities or with clinically diagnosed bilateral leg oedema were enrolled. All patients underwent duplex venous ultrasonography and lymphoscintigraphy. Venography was performed in 12 patients with normal lymphoscintigraphy and ultrasonography.

Results: The age distribution was between 20 and 54 years (mean ± SD; 22.9 ± 4.3). Among 160 patients, 70.0% had lymphoedema, while 7.5% had chronic venous insufficiency, 3.75% chronic deep venous thrombosis, 7.5% concomitant venous disease and lymphatic obstruction, and 7.5% idiopathic oedema. In the last 3.75% the pathology was Klippel–Trenaunay syndrome. Of the primary lymphoedema patients (16.25%), 18 were praecox, six tarda and two were congenital types.

Conclusion: In young male patients, the causes of secondary lymphoedema are lymphadenectomy, neoplastic metastasis, cellulitis, lymphangitis, etc. Further techniques confirmed the clinical diagnosis of lymphoedema in 77.5% (sum of lymphoedema and concomitant disease) of all patients. With these findings lymphoedema can be diagnosed clinically, and further diagnostic techniques can be reserved unless treatment is effective.
Transilluminated powered phlebectomy in the treatment of primary and recurrent varicose disease: six-month follow-up of 135 legs
Authors: Raussi M , Pakkanen J , Varila E , Kupi H , Saarinen J
Published: September 2006

Objective: Tumescent anaesthesia and transillumination can be used in removing varicose veins (VV) together with a specially designed rotating resector device and suction drain system (transilluminated powered phlebectomy, TIPP). The purpose of this study was to evaluate safety, short-term results and learning curve of this novel technique in the treatment of primary and recurrent VV.

Methods: A total of 135 legs in a cohort of 96 patients received surgery for varicose disease in one private hospital during a 14-month period. All operations were performed by a single surgeon using TIPP alone or together with hook phlebectomy and stripping of great or short saphenous vein. This retrospective data included the following issues: preoperative evaluation (Doppler or duplex), perioperative details (duration of operation, number of incisions, used techniques) and postoperative examination two weeks and six months after surgery (complications, short-term results).

Results: The mean age was 48 years and 92 patients (96%) were women. There were 39 (41%) bilateral procedures and 78 legs (58%) had a recurrent varicose disease. The distribution of clinical, aetiological, anatomical and pathophysiological clinical class was as follows: class C2 16%, class C3 79% and class C4 5%. TIPP was performed without other surgical procedures in 29 (21%) legs. Duration of operation (mean) was 81 min in primary legs, and 84 min in recurrent cases. The number of incisions was 3.2 in primary legs and 4.5 in recurrent ones. Complications were noted in 11 (8%) of the legs two weeks postoperatively. Pigmentation was noted in 10 (7%) legs (10.3% in recurrent legs and 4.0% in primary legs) and residual VV in 11 (8%) after a six-month follow-up. No major complications (deep infection, deep venous thrombosis, fat embolism, pulmonary embolism) were found during the six-month follow-up. When the beginning of the learning curve (31 legs) was compared with subsequently operated 104 legs, there were more skin lesions (6.5 versus 0%; P < 0.05), and more residual VV in the follow-up (16 versus 8%; P < 0.05) at the early stage of the learning curve. However, no difference was noted in the incidence of pigmentation, infection, haematomas or lymphatic disorders.

Conclusions: Rate of complications after TIPP is low in patients undergoing day-case surgery for varicose disease. The number of incisions is low in both primary and recurrent legs. Late pigmentation is not frequent, but the incidence of pigmentation is higher in recurrent legs. Residual varicosis is rarely seen in six-month follow-up.
Lichen planus following varicose vein surgery
Authors: Fine E , Cheatle T R
Published: September 2006

Six weeks after varicose vein surgery, a patient presented with an intensely irritating, florid, purple, papular rash. This matched the line of long saphenous vein stripping and avulsions perfectly. A diagnosis of lichen planus was made by a consultant dermatologist and confirmed histologically by biopsy. Treatment with topical corticosteroids resulted in a dramatic improvement and the rash healed to leave pigmentation.
The steepness of the dose response curve both for tumor cure and normal tissue injury
Authors: Stewart J. G. , Jackson A. W.
Published: September 2006

At the Christie Hospital in Manchester, 4 MeV radiation was introduced in 1955. In consequence of a lack of knowledge of absolute dose definition and R.B.E. factor, patients were treated over a range of dosage. Three hundred fourteen patients with laryngeal cancer, treated over a time interval of three weeks, received doses over a range of 5,000 rads to 5,800 rads. Recurrence, morbidity and necrosis rates are plotted against dose. In T1 tumors there is very little variation in recurrence rate, and such tumors may be safely treated at the lower doses thus avoiding morbidity and necrosis. T3 tumors, however, show a considerable variation in recurrence rate being 68 percent at the lower end of the range, dropping to 30 percent at the high end. Necrosis nil at the lower end rises to some 8 percent at the high end. The balance of advantage of tumor sterilization versus the disadvantage of normal tissue damage is discussed.
Spatial and Temporal Control of Laminin-332 (5) and −511 (10) Expression During Induction of Anagen Hair Growth
Authors: Sugawara Koji , Tsuruta Daisuke , Kobayashi Hiromi , Ikeda Kazuo , Hopkinson Susan B. , Jones Jonathan C.R. , Ishii Masamitsu
Published: September 2006

Basement membrane plays important roles in hair growth. We characterized changes in laminin isoform expression during hair cycling. At the mRNA level, laminin-511 (10) expression underwent a steady increase during anagen stages. In contrast, laminin-332 (5) expression was initially upregulated in outer root sheath (ORS) keratinocytes at anagen II and then transiently downregulated. Laminin-332 significantly increased coincident with the signal in inner root sheath and hair matrix cells after anagen IV. Levels of laminin-332 proteins were also upregulated at late anagen I-III but dropped after anagen IV. This decrease coincided with increased levels of mRNA encoding the two proteases, membrane type 1 metalloproteinase and bone morphogenetic protein 1, involved in laminin-332 processing. Immunohistochemistry demonstrated that laminin-332 and α6β4 integrin were well colocalized, but their signals were remarkably decreased in the lower half of follicles after anagen VI. Consistent with these data, ultrastructurally mature hemidesmosomes were seen in ORS keratinocytes at anagen II, whereas at anagen VI, only fragmental hemidesmosomes were present. In hair follicle culture, laminin-511 (10)/521 (11)-rich human placental laminin enhanced hair growth, whereas recombinant laminin-332 antagonized hair growth induced by laminin-511. Our results indicate a positive role for laminin-511 and a negative role for laminin-332 on hair growth.
Functional Magnetic Resonance Imaging of Language Function in Children
Authors: Anderson Dianne P.
Published: September 2006

Functional magnetic resonance imaging (fMRI) has been recognised as a neuroimaging technique suitable for examination of higher cognitive function in children. It has been used to elucidate cognitive neural networks associated with various aspects of language function in several group and case studies of school-aged children. Language function has been lateralised and localised with fMRI in clinical samples, neurologically normal children and children with developmental language disorders. Issues of plasticity of language function during development and following injury have also been considered. Several paediatric case studies have also raised questions with respect to the interpretation of fMRI language activation. In spite of methodological challenges, fMRI has proved a useful technique for examination of the brain-behaviour relationship in developmental language functions. This paper reviews fMRI studies of language, including reading, in children.
Implementierung der Impedanzspektroskopie in vollautomatischen Messsystemen am Beispiel der Batteriezustandsdiagnose (Battery Diagnosis as an Example for Implementing Impedance Spectroscopy in Automated Measurement Systems)
Authors: Tröltzsch Uwe , Kanoun Olfa
Published: September 2006

Die Impedanzspektroskopie wird im Labor erfolgreich für viele Anwendungen genutzt. In einer Laborumgebung können Einzelschritte durch die Intervention von Spezialisten interaktiv unterstützt werden. Für den Einsatz in vollautomatischen Messsystemen bestehen höhere Ansprüche. Im Beitrag wird am Beispiel der Batteriezustandsdiagnose dargestellt, durch welche Maßnahmen ein vollautomatisches Messsystem unter Nutzung der Impedanzspektroskopie realisiert werden kann. Schwerpunkte im Beitrag liegen auf der automatisierten Konsistenzprüfung von Messdaten mit einer praxisrelevanten Realisierung der Kramers-Kronig Transformation, der Gestaltung von Modellen und der Gestaltung des Optimierungsproblems. Vergleichbarkeit und Eindeutigkeit relevanter Parameterwerte von Impedanzmodellen grundlegender Mechanismen werden durch Eliminieren von Mehrdeutigkeiten und Normierung der Impedanzmodelle erreicht. Für die automatische Modellparameterextraktion wird vorgeschlagen, die Modellparameter durch Anpassung von Teilmodellen an automatisiert ermittelte Wirkungsbereiche zu extrahieren.
Method of Soil Moisture Measurement by Impedance Spectroscopy with Soil Type Recognition for In-Situ Applications (Messverfahren zur Bodenfeuchtemessung mittels Impedanzspektroskopie mit Bodenarterkennung für In-situ-Anwendungen)
Authors: Tetyuev Andrey , Kanoun Olfa
Published: September 2006

Soil moisture sensor systems need extensive calibration processes because of the dependence on soil properties. A novel measurement method is presented which is based on impedance spectroscopy. This method takes advantage of impedance spectroscopy for the characterization of soil type and measurement of soil moisture with improved accuracy. A comprehensive compensation of cross-sensitivity effects is carried out. The soil type characterization was carried out by a multivariate analysis based on elaborated experimental investigations of different natural soils. The results show that the new measurement method provides a measurement accuracy that fulfills the requirements of respective applications.
Automatische Lüftung zur Sicherung von Behaglichkeit, Luftqualität und Energieeinsparung im privaten Lebensbereich (Regulated Ventilation to Ensure Thermal Comfort, Air Quality and Energy Conservation in Residential Homes)
Authors: Horn Michael , Zhelondz Dmitri , Ruser Heinrich , Pawelczak Dieter R.
Published: September 2006

Die bedarfsgerechte Lüftung von Räumen hat großen Einfluss auf das Wohlbefinden und die thermische Behaglichkeit von anwesenden Personen sowie auf den Energieverbrauch. Um eine gezielte Frischluftzufuhr in Wohnräumen zu ermöglichen, benötigt eine automatische Lüftungssteuerung Messsysteme zur Luftqualitätsbeurteilung, insbesondere zur Erfassung der Konzentration des Leitgases Kohlendioxid (CO2) sowie der Feuchte. Messtechnische Untersuchungen ergaben, dass die Messung der CO2-Konzentrationen im Raum an allen nicht direkt von Außenluft berührten Positionen erfolgen kann. Die Auswertung des Heizenergieverbrauchs zeigte, dass — entgegen der bisher vorherrschenden Meinung — eine geregelte kontinuierliche Spaltlüftung keine energetischen Nachteile gegenüber der Stoßlüftung hat. Zusammen mit der verbesserten thermischen Behaglichkeit aufgrund viel geringerer Temperaturschwankungen und deutlich reduziertem Zugluftrisiko erweist sich die geregelte Spaltlüftung als überlegen zur Sicherung von Behaglichkeit, Luftqualität und Energieeinsparung im privaten Lebensbereich.
Epidemiology of Hoffmeister's “Genetically Determined Predisposition to Disturbed Development of the Dentition” in Patients with Cleft Lip and Palate
Authors: Stahl Franka , Grabowski Rosemarie , Wigger Katrin
Published: September 2006

Objective

Type and prevalence rates of the symptoms of Hoffmeister's “genetically determined predisposition to disturbed development of the dentition” were studied in patients with clefts.

Patients

Data of 263 patients with nonsyndromic clefts of lip (alveolus and palate) or isolated cleft palates were examined in a retrospective study.

Setting

The clefts were classified as cleft lip or cleft lip and alveolus, cleft palate, unilateral cleft lip and palate, and bilateral cleft lip and palate. All patients were scrutinized for 28 individual symptoms. Prevalences of the individual symptoms were statistically evaluated regarding cleft type and gender by using the chi-square test and were also compared with findings in patients without clefts.

Results

In 97.7% of the patients with clefts, at least one symptom was found. Microdontia of individual teeth, hypodontia, and hyperodontia were the symptoms most frequently recorded. Comparison of the different cleft types revealed differences regarding the prevalences of supernumerary lateral incisors (p = .051), infraposition of deciduous molars (p < .001), and atypical tooth bud position (p = .030). Comparison of the prevalences of 10 symptoms recorded in the patients with clefts with the prevalences recorded in patients without clefts showed nine symptoms were found much more frequently in the population with clefts.

Conclusion

These findings support the hypothesis that clefting is part of a complex malformation associated with other dental anomalies resulting from disturbed development of the dentition. Patients with clefts are also likely to present other deficiencies of dental development and tooth eruption in both dentitions, even in regions not affected by the cleft.
Structural Birth Defects Associated with Oral Clefts in Hawaii, 1986 to 2001
Authors: Forrester Mathias B. , Merz Ruth D.
Published: September 2006

Objective

To identify structural birth defects that occur in association with oral clefts.

Methods

Data were obtained from a birth defects registry and included all infants and fetuses with cleft palate without cleft lip or cleft lip with or without cleft palate delivered from 1986 to 2001. For 47 specific structural birth defects, rates among oral cleft cases were compared with the rates among all infants and fetuses with major birth defects, excluding those with oral clefts.

Results

Among cleft palate only cases, the rates were significantly higher than expected for encephalocele, microcephaly, and syndactyly. Among cases of cleft lip with or without cleft palate, the rates were significantly higher than expected for anophthalmia/microphthalmia, single ventricle, reduction deformity of upper limbs, and reduction deformity of lower limbs. When cases of cleft palate only and cleft lip with or without cleft palate were compared as to the rates for particular birth defects, the rates of the defects were either higher or lower than expected in both oral cleft categories for 38 (81%) of the defects.

Conclusions

Certain birth defects were more frequently associated with oral clefts than might be expected. For the majority of defects, their patterns of association were similar between cleft palate without cleft lip and cleft lip with or without cleft palate.
Effect of additives on the properties of α-hemihydrate
Authors: Panpa W. , Jinawath S.
Published: September 2006

The effects of Na-succinate and succinic acid on the properties of the α-hemihydrate synthesised from the fluegas desulphurised (FGD) gypsum of the Mae Moh power plant, northern Thailand, by the classical vapour process, were studied in comparison with natural gypsum. It was found that the additives strongly affected the content and microstructure of the α-hemihydrate, and consequently the properties of its dihydrate. The physical and mechanical properties of the hydrated plaster were investigated in conformity with dental stone (type III). The additives, in an appropriate concentration, favoured the increase in α-hemihydrate phase but they tended to reduce the aspect ratio (c/a axis) of both the α-hemihydrate and its dihydrate crystals. Hence the morphology of the α-hemihydrate changed from long and prismatic towards a short and thick rod, and that of the dihydrate, from a long and thin plate to a small and thick plate. In comparison, the effect of the additives on the FGD gypsum was more drastic, and between the two additives, the effect of succinic acid was stronger. Alpha-plaster containing > 99 wt.% α-hemihydrate and dental stone having compressive strength of 28·75 MPa at a water/ plaster ratio of 0·32 were successfully produced from the FGD gypsum.
Influence of some organic admixtures on the rheological and mechanical properties of cement pastes
Authors: Aiad I.
Published: September 2006

Three organic admixtures were used; melamine formaldehyde sulphonate, phenol formaldehyde sulphonate and polycarboxylate. The effects of these polymers on the fluidity and fluidity loss of cement pastes were investigated. The polymers were added by two different methods: either together with mixing water (simultaneous addition) or at a specified time (15 min) after mixing with water (later addition). The mini-slump of these pastes at different time intervals of 30, 60, 90 and 120 min was determined. The 28-day compressive strength and differential scanning calorimetry of hardened cement pastes that had been made by the two addition methods were determined. The results revealed that the organic admixtures reduced the mini-slump loss (by time) of fresh cement pastes, which were prepared by the two methods. The effectiveness of later addition was greater than that of simultaneous addition not only at early ages (30 min) but also at later ages (120 min).
Evaluation of UV disinfection systems for large‐scale secondary effluent
Authors: Ho Chu‐Fei H. , Pitt Paul , Mamais Daniel , Chiu Carolyn , Jolis Domenéc
Published: September 2006

A study at the Southeast Water Pollution Control Plant, San Francisco, California, was undertaken to evaluate the feasibility of replacing its current secondary effluent chlorination system with a 6.57 m3/s ultraviolet (UV) disinfection system. Two vertical lamp units and one horizontal lamp unit were pilot tested in parallel. The effective UV dose for coliform removal and the effects of feedwater characteristics and reactor hydraulics were examined. The horizontal pilot unit gave a more consistent performance than the vertical pilot units. Based on the test results, a UV dose of 65 mW·s/cm2 would be required for the plant to achieve the target effluent total coliform level (240 CFU/100 mL) 95% of the time. The large fluctuation of UV disinfection results could be attributed to the wide range of feedwater quality inherent to a combined sewer system. High suspended solids, characteristic of the plant's secondary effluent during storm events, significantly increased the UV dose required to achieve the target coliform level. Existing UV inactivation models were evaluated. The hydraulic behavior of the pilot units was found to significantly affect their test results. Higher virus removal efficiency was observed with the UV systems than the full‐scale chlorination system.
Modeling of aerobic wastewater transformations under sewer conditions in the Emscher River, Germany
Authors: Bjerre H. Løkkegaard , Hvitved‐Jacobsen T. , Teichgräber B. , Schlegel S.
Published: September 2006

The Emscher River in the Ruhr District, Germany, currently serves as a large wastewater collector receiving untreated, mechanically treated, and biologically treated wastewater. Previous investigations in the river show that bulk water transformations of organic matter under aerobic conditions play a dominant role compared with transformations in the biofilm and sediment. It was found that the activated‐sludge concept for modeling bulk water processes under aerobic and anoxic conditions in wastewater treatment plants can be used for the Emscher River when the model is extended to include three hydrolysis processes instead of only one. In 17 experiments covering variations in time and space in the Emscher River, measurements of the oxygen uptake rate (OUR), concentration of easily and slowly biodegradable organic matter, and viable biomass were used to find the stoichiometric and kinetic constants suitable for process modeling. One set of constants was found suitable for model simulations of the river, and a simple model simulation was performed for two reaches of the river. Under aerobic conditions the model simulations showed that approximately 40% of the chemical oxygen demand transformed was easily biodegradable and that the transformation was found to be directly proportional to the concentration of viable biomass when no limitations of easily biodegradable organic matter were present. The modeling concept is general and can be proposed for simulations of wastewater transformations under transport in gravity sewers under aerobic conditions.
The effect of reformulation of household powder laundry detergents on their contribution to heavy metals levels in wastewater
Authors: Jenkins David
Published: September 2006

Studies have demonstrated that numerous sources contribute to the levels of heavy metals found in municipal wastewater, including the water supply, industry, and residential activities. An earlier study identified the heavy metals contribution of household washing products compared to other sources. Since that time, a major nationwide reformulation of powder laundry detergents has taken place, warranting a reexamination of their heavy metals contributions. In addition, the wastewater systems that were the subject of the previous study have instituted industrial source controls that have reduced heavy metals from them. As in the previous study, heavy metals analyses of current household powder laundry detergent and product usage rates were used to determine the contributions of household washing products to levels of heavy metals in influent and effluent wastewaters. The heavy metals contributions from household washing products to current and future effluent limits were determined to be 0.5% or less for cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc. The highest heavy metal contribution from household washing products was for arsenic, which accounts for 2% and 1% of current and future permit levels, respectively.
The effect of cationic salt addition on the settling and dewatering properties of an industrial activated sludge
Authors: Novak John T. , Love Nancy G. , Smith Michelle L. , Wheeler Elliott R.
Published: September 2006

Cations have been found to influence the settling and dewatering properties of activated sludge, especially for industrial wastewaters in which very high concentrations of monovalent cations are often found. Because the cation content of wastewaters is often influenced by upstream processes, an understanding of the influence of various cations can be an important consideration in pinpointing operational problems in wastewater treatment plants. An industrial activated‐sludge treatment plant was studied to determine whether variations in settling and dewatering properties of the mixed liquor and waste solids could be caused by changes in the cation content of the wastewater. Laboratory reactors received both return activated sludge and wastewater from the industrial treatment plant, and the feed was supplemented with either sodium (Na+), potassium (K+), or magnesium (Mg+). It was found that when the monovalent‐to‐divalent (M:D) cation ratio on a milliequivalent basis was increased to greater than approximately 2:1 by either Na+ or K+ addition, dewatering properties became poorer and polymer conditioning requirements increased. The soluble protein content also increased as the mixed liquor M:D ratio increased, indicating release of biopolymer from the flocs. Magnesium addition at low doses caused a decrease in the dewatering rate, but at higher doses both the settling and dewatering properties of waste solids improved substantially. Conversely, when Na+ and K+ concentrations in the raw wastewater decreased significantly to less than 10 and 0.1 milliequivalents (meq), respectively, settling and dewatering properties improved substantially and addition of Mg2+ did not improve conditions beyond those of the unamended control. Each of the cations studied caused unique changes in the properties of activated‐sludge solids that could not be correlated with the M:D ratio, suggesting that some of the effects are not simply physical/chemical but may be physiological as well.
Nutrient transport and transformation beneath an infiltration basin
Authors: Sumner D.M. , Rolston D.E. , Bradner L.A.
Published: September 2006

Field experiments were conducted to examine nutrient transport and transformation beneath an infiltration basin used for the disposal of treated wastewater. Removal of nitrogen from infiltrating water by denitrification was negligible beneath the basin, probably because of subsurface aeration as a result of daily interruptions in basin loading. Retention of organic nitrogen in the upper 4.6 m of the unsaturated zone (water table depth of approximately 11 m) during basin loading resulted in concentrations of nitrate as much as 10 times that of the applied treated wastewater, following basin “rest” periods of several weeks, which allowed time for mineralization and nitrification. Approximately 90% of the phosphorus in treated wastewater was removed within the upper 4.6 m of the subsurface, primarily by adsorption reactions, with abundant iron and aluminum oxyhydroxides occurring as soil coatings. A reduction in the flow rate of infiltrating water arriving at the water table may explain the accumulation of relatively coarse (>0.45 μm), organic forms of nitrogen and phosphorus slightly below the water table. Mineralization and nitrification reactions at this second location of organic nitrogen accumulation contributed to concentrations of nitrate as much as three times that of the applied treated wastewater. Phosphorus, which accumulated below the water table, was immobilized by adsorption or precipitation reactions during basin rest periods.
A systematic analytical artifact that significantly influences anaerobic digestion efficiency measurement
Authors: Beall Steven S. , Jenkins David , Vidanage Srimalie A.
Published: September 2006

Volatile solids reduction efficiency is widely used to assess the efficiency of anaerobic digestion of municipal wastewater sludge. When calculation methods that rely on the assumption that the nonvolatile or fixed solids are unaltered by anaerobic digestion have been used, it has been observed that higher volatile solids reduction efficiencies are typically obtained with primary sludge digestion than when waste biological sludges are digested. The research reported in this paper demonstrates that this difference in efficiency largely results from an artifact caused by the decomposition of ammonium bicarbonate during the total solids analysis.
Biodegradable dissolved organic carbon for indicating wastewater reclamation plant performance and treated wastewater quality
Authors: Khan Eakalak , Babcock Roger W. , Viriyavejakul Sarunyu , Suffet Irwin H. , Stenstrom Michael K.
Published: September 2006

Various methods for measuring biodegradable dissolved organic carbon (BDOC) in water have been introduced in the last decade. Applications of the methods have been limited to drinking water. The measure of BDOC has been used mainly to indicate the quality of raw and finished waters and evaluate the performance of biological activated carbon (ozone/granular activated carbon) systems in water treatment plants. Recently, a modified BDOC protocol was developed for examining reclaimed and secondary‐treated wastewaters. Use of the new BDOC method can be extended to the wastewater treatment and reclamation fields. Samples collected from a wastewater reuse pilot facility were tested for BDOC. The modified BDOC method was able to detect the increase in biodegradability of ozonated tertiary‐treated wastewater. Good relationships among BDOC, dissolved organic carbon (DOC), and soluble biochemical oxygen demand were obtained. The modified protocol was later used to measure BDOC in secondary‐effluent samples from 13 municipal wastewater treatment plants. The results show that BDOC can also be used as an indicator of secondary‐effluent quality. Likewise, strong and significant correlations were found among BDOC, DOC, and soluble chemical oxygen demand in secondary effluents.
Acid characteristics of dissolved organic matter in wastewater
Authors: Wang Jianmin , Huang C.P. , Allen Herbert E. , Takiyama Luis R. , Poesponegoro Ira , Poesponegoro Haryanto , Pirestani Dan
Published: September 2006

The presence of dissolved organic matter (DOM) in a wastewater treatment system can significantly affect the uptake of heavy metals by sludge particulates. The characteristics of DOM, its concentration, and the solution pH are important parameters governing the heavy metals uptake reaction. The characteristics of DOM of various wastewater and sludge (primary, secondary, and tertiary) samples collected from four municipal wastewater treatment plants were investigated. Results showed that the dissolution of DOM from sludge is significantly affected by pH and suspended solids concentration. Results also showed that DOM contains two discrete acid groups that are available for metals complexation. The site concentration and acidity constants were determined by an alkalimetric titration method. For all DOM samples studied, the acidity constants, pKab and pKaB, were 5.3 and 9.5, respectively. Based on the acidity constants and the Fourier transform infrared spectra, it is believed that the acid sites consist of carboxylic and amino functional groups. The density of the first acid site was approximately 10−5 mol/mg chemical oxygen demand for all samples studied. However, the density of the second acid site varied significantly among the DOM samples investigated.
Biodegradation of tetryl (2,4,6‐trinitrophenylmethylnitramine) in a soil‐slurry reactor
Authors: Boopathy Ramaraj , Manning John
Published: September 2006

A laboratory study was conducted to determine whether tetryl can be biodegraded by native soil bacteria under soil‐slurry conditions with molasses as cosubstrate. A 2‐L laboratory reactor was set up with a 15% (weight/volume) slurry of contaminated soil in deionized water. The soil slurry was mixed continuously at 80 r/min. Molasses at 0.3% (volume/volume) was added weekly as a cosubstrate. A no‐carbon control reactor was also set up without molasses addition. The concentration of tetryl in the soil was monitored periodically. The results showed 100% removal of tetryl from the soil within 3 months of operation. In the no‐carbon control, no significant degradation of tetryl was observed. The gas chromatographic/mass spectrometric analysis of the aqueous phase of the soil slurry showed metabolites identified as trinitro‐n‐methylaniline, trinitrobenzeneamine, dinitrobenzenediamine, nitroaniline, and aniline. None of these metabolites persisted more than a week after they appeared in the reactor system. The parameters relevant to biodegradation and process control, such as pH, dissolved oxygen, bacterial counts, and metabolites produced in the reactor, are discussed.
Anaerobic treatment of olive mill wastewater with digested piggery effluent
Authors: Marques I.P. , Teixeira A. , Rodrigues L. , Dias S. Martins , Novais J.M.
Published: September 2006

Anaerobic digestion of olive mill wastewater (OMW) in admixture with anaerobically digested piggery effluent (ADPE) was investigated. Successive volumetric increases of OMW ranging from 8 to 91% were mixed with ADPE and treated through an upflow anaerobic filter to promote gradual adaptation of the microbial consortium. The response of the digester was positive, and only at 91% v/v OMW was lower reactor performance obtained, suggesting that a concentration on the order of 83% v/v was the highest in terms of the efficiency and stability of the reactor. At this inlet composition, the mixture loading rate varied from 5.0 to 5.7 kg chemical oxygen demand (COD)/m3·d and the total COD removal was 73 to 75%, with a gas production of 1.7 to 2.1 m3/m3·d (66 to 68% CH4). The corresponding volume of ADPE (17%) was enough to maintain an influent ammonium‐nitrogen (NH4+‐N) concentration of 0.17 to 0.19 kg NH4+‐N/m3 which was practically spent.
A new biosensor for rapid oxygen demand measurement
Authors: An Lichao , Niu Hong , Zeng Heng
Published: September 2006

A biosensor for the determination of oxygen demand (OD) using bacteria isolated from activated sludge has been developed. This sensor allowed OD measurement with a short response time, an operation stability of 48 days, and a serial coefficient of variation of ±1.3% when a sample solution with 6.6 mg/L OD was employed. A linear range was obtained up to 32.8 mg/L OD using a glucose–glutamic acid standard solution. Comparable results were obtained for OD values estimated by the biosensor and biochemical oxygen demand (BOD) determined by the 5‐day method. The biosensor was applied to on‐the‐spot estimation of OD for the effluent from wastewater treatment plants.
The influence of pH and ammonia concentration on the methane production in high‐solids digestion processes
Authors: Lay Jiunn‐Jyi , Li Yu‐You , Noike Tatsuya
Published: September 2006

The influence of pH and ammonium‐nitrogen on methane production in a high‐solids sludge digestion process was investigated using a mesophilic batch digester fed with a sludge cake. A simple model developed from the Gompertz equation was applied to the quantitative measurement of the methane production rate and lag‐phase time at pHs ranging from 6.5 to 9.0 and ammonium‐nitrogen concentrations ranging from 100 to 6 000 mg/L. The results indicate that the ammonium‐nitrogen concentration was a more significant factor than the free ammonia in affecting the methanogenic activity of a well‐acclimatized system. The simulated results reveal that the methanogenic activity decreased with an increase in ammonium‐nitrogen, dropped 10% at an ammonium‐nitrogen concentration of 1 670 to 3 720 mg/L, dropped 50% at 4 090 to 5 550 mg/L, and dropped to zero at 5 880 to 6 000 mg/L. The lag‐phase time in the batch experiment was dependent on the ammonia level, but not ammonium, and when the free ammonia concentration was higher than 500 mg/L, a notable shock load was observed. In addition, the maximum methane‐converting capacity of sludge changed from 28 to 0.9 mL CH4/g VS·d when the ammonium‐nitrogen concentration increased from 100 to 6 000 mg/L.
Biological nitrogen removal from coke plant wastewater with external carbon addition
Authors: Lee Min Woo , Park Jong Moon
Published: September 2006

Coke plant wastewater containing high concentrations of ammonia and toxic compounds such as phenol and cyanide was treated using a biological nitrogen removal (BNR) system comprising carbon removal, nitrification, and dentrification stages. The objective of this study was to investigate the feasibility of complete ammonia removal from the coke plant wastewater using a sequential BNR process with external carbon addition. Sodium acetate was introduced as an external carbon source to the denitrification stage after oxidation of phenol and other carbonaceous compounds in the carbon‐removal stage. The efficiency of denitrification was strongly affected by the loading rate of the external carbon source, and its optimal rate was determined based on the ratio of chemical oxygen demand to nitrate‐ and nitrite‐nitrogen (COD:NOx‐N) of the denitrification stage. The overall removal efficiency of major soluble pollutants in the wastewater was greater than 95% in the BNR system. When a step input of phenol was introduced to check the stability of the overall system, the nitrification was markedly inhibited because of the incomplete degradation of phenol in the carbon‐removal stage. However, after this brief inhibition, the nitrification stage recovered to its normal efficiency within 18 days.
Comparative animal and plant toxicities of 10 treated effluents discharged to near‐coastal areas of the Gulf of Mexico
Authors: Lewis Michael A. , Weber David E. , Stanley Roman S.
Published: September 2006

The chemical quality and acute and chronic toxicities of 10 effluents discharged to near‐coastal areas in Northwest Florida were determined using standard and nonstandard toxicity tests. The primary objectives of the study were to evaluate and compare the toxicities of different types of effluents and to assess the ability of a variety of toxicity tests to differentiate effluent‐specific effects. Focus was placed on animal–plant sensitivity comparisons because phytotoxicity is rarely determined for effluents discharged to coastal estuaries. The standard toxicity test organisms included two algae, two invertebrates, and two fish. In addition, effluent toxicity was evaluated using three rapid bioassays and an early‐seedling‐growth toxicity test. Most concentrations of potentially toxic inorganic and organic contaminants in the effluents were low, a finding that contrasted with the sometimes elevated biochemical oxygen demand and nutrient concentrations. With the exception of their effects on algae, the toxicities of most effluents were considered moderate. Chronic effects on Ceriodaphnia dubia and Mysidopsis bahia were observed consistently for five effluents; the lowest first‐effect levels were typically 35 or 71% effluent. Inhibitory effects on fish and macrophyte seedling growth were infrequent, as were those determined using the three rapid bioassays. Nine of the ten effluents were either phytotoxic or phytostimulatory to algae; first effects were noted in some cases at effluent concentrations less than 6%. Overall, the results indicate the importance of using invertebrates, but more so algae, as test species in the hazard‐evaluation process for effluents discharged to Gulf of Mexico near‐coastal areas, which are frequently nutrient‐affected. Furthermore, additional development of tests using rooted aquatic plants is needed because the effects of effluents in this coastal area on plant‐dominated coastal habitats (wetlands) and on plant species at risk (sea grasses) are not well understood.
Advanced steady‐state model for the fate of hydrophobic and volatile compounds in activated sludge
Authors: Lee Kuan‐Chun , Rittmann Bruce E. , Shi Jichun , McAvoy Drew
Published: September 2006

A steady‐state, advanced, general fate model developed to study the fate of organic compounds in primary and activated‐sludge systems. This model considers adsorption, biodegradation from the dissolved and adsorbed phases, bubble volatilization, and surface volatilization as removal mechanisms. A series of modeling experiments was performed to identify the key trends of these removal mechanisms for compounds with a range of molecular properties. With typical municipal wastewater treatment conditions, the results from the modeling experiments show that co‐metabolic and primary utilization mechanisms give very different trends in biodegradation for the compounds tested. For co‐metabolism, the effluent concentration increases when the influent concentration increases, while the effluent concentration remains unchanged when primary utilization occurs, For a highly hydrophobic compound (partition coefficient Kd > 0.01 m3/g VSS), the fraction of compound removed from adsorption onto primary sludge can be very important, and the direct biodegradation of compound sorbed to the activated sludge greatly increases its biodegradation and reduces its discharge with the waste activated sludge. Volatilization from the surface of the primary and secondary systems is important for compounds with moderate to high volatilities (Henry's law constant Hc = 0.001 to 0.1 m3 water/m3 air), especially when these compounds are not biodegradable. Finally, bubble volatilization can be a major removal mechanism for highly volatile compounds (Hc > 0.8 m3 water/m3 air), even when they are highly biodegradable.
Time‐of‐travel in the lower Mississippi River: model development, calibration, and application
Authors: Waldon Michael G.
Published: September 2006

The Mississippi River is the source of drinking water for more than 1 million Louisiana residents. The river also is used for transportation of hazardous chemicals and petroleum products, and is the receiving stream for wastewater effluents from numerous industries and municipalities. To minimize the public's risk from contaminant spills and accidental discharges, drinking water providers need timely warning of approaching contaminants. Based on a modified plug‐flow (MPF) formulation, a time‐of‐travel model has been developed to provide projections of the time of arrival, peak arrival time, time of passage, and duration of contaminant spills on the Mississippi River. Estimates of the peak concentrations of contaminants passing downstream locations are calculated from spill mass, discharge, and calculated duration. The model used for this research was calibrated using dye time‐of‐travel studies. The primary objective of this model is to facilitate the timely warning of drinking water providers. Additionally, this model may be of value in other water quality management applications, including contingency planning, impact assessment, monitoring, enforcement, and surveillance.