The circulating fluidized bed bioreactor as a biological nutrient removal process for municipal wastewater treatment: Process modelling and costing analysis.

Emerging technologies for wastewater treatment face an uphill battle to be adopted in practice because no large-scale costing data exists to prove their cost competitiveness. Similar technologies and their costing data offer some insight to the approximate cost, but more detailed estimates are required for a final decision on process selection. The circulating fluidized bed bioreactor (CFBBR) is one such technology, proven at the lab and pilot and scale, but is yet to be used on a large scale. In order to demonstrate the potential economic competitiveness of the CFBBR, a method of modifying the CapdetWorks costing software by first modeling the CFBBR in the GPS-X process simulation software was employed. The modelling was used to determine the necessary changes to a moving bed bioreactor (MBBR) process (media size, density, surface area, and bed fill fraction) in CapdetWorks to simulate the CFBBR and then generate costing estimates for both capital cost (CapEx) and operation and maintenance cost (OpEx). Benchmarking the cost estimates against simulations of conventional suspended and attached growth processes and external costing data from the US EPA was performed to both validate the costing method and analyze the CFBBR's economic competitiveness. The calculation of the net present value from the CapEx and OpEx showed that the CFBBR is predicted to have 10%-30% lower costs at low flows of 1.5 and 4.6 MGD and comparative costs to conventional processes at higher flows from 10 to 30 MGD. Furthermore, the smaller land footprint of the CFBBR-based plants and lower landfilled biosolids implies that the CFBBR's environmental footprint is superior to its competitors and offers advantages for both small-sized plants and large urban plants.

Decentralized wastewater treatment in an urban setting: a pilot study of the circulating fluidized bed bioreactor treating septic tank effluent.

To meet the increasing wastewater treatment demand while minimizing the land footprint of the treatment systems and plants, more efficient and compact processes are needed. The circulating fluidized bed bioreactor (CFBBR) has been proven to achieve high levels of biological nutrient removal. Past studies at the lab and pilot scale achieved 94% COD removal and 80% nitrogen removal at HRT's of 2-4 h. A collaborative project between Western University and the Guangzhou Institute of Energy Conversion (GIEC), in Guangzhou, China, further explored the treatment of municipal wastewater with the CFBBR. A pilot CFBBR, with aerobic and anoxic columns for nitrification and denitrification, was constructed at the GIEC for in-situ treatment of septic tank effluent from a residential building. Due to high concentrations of ammonia (NH4-N), the wastewater had a COD/N ratio of 2-3. Thus, operating at a longer HRT and supplementing COD, in the form of glucose, was necessary to achieve a high nitrogen removal efficiency. The system was run both with and without supplemental COD at HRT's between 16 and 21 h, treating approximately 1000-1270 L/d. Overall, a COD removal efficiency of at least 92%, ammonia removal of 97%, and nitrogen removal of 82% was achieved. The CFBBR system achieved an effluent with BOD and NH4-N concentrations both below 5 mg/L, a NO3-N concentration below 15 mg/L, and a total nitrogen concentration below 25 mg/L. The compact design of this pilot-CFBBR, coupled with its high BNR performance make it an excellent option for decentralized treatment of urban wastewaters.

Case report: vertebral osteomyelitis/discitis as a complication of Capnocytophaga canimorsus bacteremia.

A 31-year-old man with a history of congenital ventricular septal defect presented to the Emergency Department with 3 days of fever and palpitations. Four days earlier he sustained a dog bite to the left hand with localized swelling that rapidly resolved without additional signs of infection. No other source of fever was identified on history and physical examination. He was admitted to the hospital for evaluation of the origin of the fever, including possible endocarditis. Complete cardiac evaluation revealed no valvular infection. On the fifth hospital day, the patient developed severe lower back pain. Magnetic resonance imaging of the lumbar spine revealed L4-5 vertebral osteomyelitis and discitis. Blood cultures were positive for Capnocytophaga canimorsus. Antibiotics were continued and recovery was complete and uneventful.

The normal difference in bilateral indirect blood pressure recordings in hypertensive individuals.

OBJECTIVE: If there is a significant dichotomy between bilateral systolic blood pressure determinations in both arms in hypertensive individuals, it is often taken as a sign of underlying pathology. The primary objective was to determine what the normal variation might be for a significant difference between blood pressures in both arms. A clinically significant difference was chosen as a systolic blood pressure value greater than 10 mm Hg between the upper extremities, as is commonly quoted at the bedside and in the literature. METHODS: Bilateral indirect blood pressure determinations were obtained in 100 subjects with hypertension in the sitting position. The blood pressure was obtained by two observers, one the recorder and the other who obtained the blood pressure but was blinded to the actual values taken. The order of blood pressure determination in the first arm was determined prior to the study from a table of random numbers. The coefficient of variation in obtaining the blood pressure in each arm was determined in 5 of the 100 subjects. The age, sex, and handedness of each individual were recorded as demographic variables. RESULTS: The average left and right systolic blood pressures were 139 +/- 22 and 141 +/- 22 mm Hg, respectively. The average left and right diastolic blood pressures were 78 +/- 12 and 79 +/- 13 mm Hg, respectively. There was no significant difference between left minus right systolic or diastolic differences (paired t-test). There was no significant difference between systolic or diastolic blood pressures between gender or between left- and right-handed individuals (nonpaired t-test). The average coefficients of variation for taking right and left arm systolic pressures were 2.90% and 1.32%, respectively. Eighteen subjects (18%) had differences in systolic blood pressure between both arms exceeding 10 mm Hg (10% to 26%, 95% confidence interval). CONCLUSIONS: Differences of more than 10 mm Hg in indirect systolic blood pressure recordings between arms are frequent in asymptomatic hypertensive individuals and do not per se indicate any pathologic condition. In the right clinical situation, differences that are noted should be repeated and should be added to the total clinical picture when used to determine whether a pathologic condition is present. Assuming no significant aortic or subclavian disease in the population tested, the specificity of the bilateral blood pressure test was 82%.

Evaluacion de dos formulaciones de Bacillus thuringiensis H-14 para el control de larvas de Aedes aegypti / Evaluation of two formulations of Bacillus thuringiensis H-14 for the control of Aedes aegypti larvaes

Se evaluaron en el laboratorio y en condiciones naturales, dos formulaciones de bacillus thuringiensis H-14, el cual es un insecticida microbiologico contra larvas de aedes aegypty. Se utilizo polvo humectable (3.500 AA/mg) y liquido concentrado (1.000 AA/mg) (AA= unidades Toxicas internacionales en A. aegypti). Se calcularon las dosis letales (Dl 99.9) para cada formulacion. En una estacion de laboratorio que simulaba las condiciones naturales de cria de A. aegypti, se relaizaron pruebas con cuatro dosis diferentes de cada una de las dos formulaciones. Con cada dosis de 1.050 AA/I, se encontro una accion residual de 11 dias con el polvo humectable y de 9.9 dias con el liquido concentrado. La accion residual no aumento en proporcion directa con la dosis. la tasa de emergencia diaria de adultos tardo 21.7 dias en recuperarse hasta el 30% de su nivel de pretratamiento, cuando se aplico polvo humectable y 18 dias cuando se aplico liquido concentrado. Aunque en las pruebas en condiones seminaturales, se encontraron diferencias estadisticamente significativas entre las difernetes dosis y los diferentes tipo de criaderos, operacionalmente estas diferencias no tienen iomportancia practica porque no aumentan el rendimiento de la medida de control. Los ensayos en condiciones naturales se realizaron aplicando una dosis de 1.050 AA/I a las albercas, toneles y llantas. El B. t H-14 demostro ser efectivo, al causar 100% de mortalidad en todos los estadios larvarios. de A.aegypti en los criaderos tratados. Se obtuvo una accion residual de 9 dias en los criaderos cuando...

Aedes aegypti: biology and ecology / Aedes Aegypti: biologia y ecologia

[From Preface] This manual will contribute to the training of health care personnel in the methodology for study, surveillance, and control of Aedes aegypti.

Aedes Aegypti: biologia y ecologia / Aedes Aegypti: Biology and ecology

[Prefacio] El moquito Aedes aegypti y la enfermedades que transmiten, e dengue y la fiebre amarilla, todavía están presente en las Américas. la situación creada de emergencia creada por la epidemia de dengue clásico que afecto durante 1977-1978 a las mayoría de los países del caribe, Centro América, el norte de América del Sur y México, y la primera epidemia de dengue hemorrágico registrada en Cuba durante 1981, han renovado el interés de fortalecer los programas de control o erradicación del Aedes aegypti e los países de la región

Hallazgo de Mesocyclops Aspericornis (Daday)(Copepoda: Cyclopidae) Depredador de Larvas de Aedes Aegypti en Anapoima-Colombia. (1) / Finding of Mesocycolps Aspericonis (DaDay) (Copepoda: Cyclopidae) Depredator of Aedes Aegipty in Anapoima-Colombia. (1)

En Anapioma, Colombia, se encontro que el Copepodo Mesocyclops Aspericornis era depredador de larvas del mosquito Aedes Aegypti. Este encuentro representa el primer hallazgo de este Copepodo en recipientes artificiales en la region neotropical, y el primer hallazgo como depredador de larvas de Aedes Aegypti