Quantitative image analysis for the characterization of microbial aggregates in biological wastewater treatment : a review

Quantitative image analysis techniques have gained an undeniable role in several fields of research during the last decade. In the field of biological wastewater treatment (WWT) processes, several computer applications have been developed for monitoring microbial entities, either as individual cells or in different types of aggregates. New descriptors have been defined that are more reliable, objective, and useful than the subjective and time-consuming parameters classically used to monitor biological WWT processes. Examples of this application include the objective prediction of filamentous bulking, known to be one of the most problematic phenomena occurring in activated sludge technology. It also demonstrated its usefulness in classifying protozoa and metazoa populations. In high-rate anaerobic processes, based on granular sludge, aggregation times and fragmentation phenomena could be detected during critical events, e.g., toxic and organic overloads. Currently, the major efforts and needs are in the development of quantitative image analysis techniques focusing on its application coupled with stained samples, either by classical or fluorescent-based techniques. The use of quantitative morphological parameters in process control and online applications is also being investigated. This work reviews the major advances of quantitative image analysis applied to biological WWT processes.The authors acknowledge the financial support to the project PTDC/EBB-EBI/103147/2008 and the grant SFRH/BPD/48962/2008 provided by Fundacao para a Ciencia e Tecnologia (Portugal)

OUR EXPERIENCE WITH TREATMENT OF CHRONIC MYELOID LEUKEMIA WITH IMATINIB MESYLATE

<p>Background. Imatinib mesylate is an Abl kinase inhibitor capable of producing a sustained complete molecular response in chronic myelogenous leukemia (CML). It is effective in all three phases of CML with the longest response in the chronic phase. Imatinib has been in use only since 1998 and many questions about its efficacy and use are still unanswered.</p><p>Methods and results. From October 2001 until January 2004 thirty-one patients with CML have been treated with imatinib (300–600 mg/day) at our institution. Twelve patients were in chronic phase of CML, 13 in accelerated phase and 3 in blast crisis. Two were treated after unrelated peripheral blood stem cell transplantation (PBSCT) due to CML reactivation. All had been treated prior to instituting imatinib (hydroxiurea, interferon – alpha, cytarabine). Complete cytogenetic response (CCR) in patients in chronic phase occured in 33.3% and complete molecular response (CMR) occured in 41.7%. CCR in patients in accelerated phase occured in 30.8% and CMR occured in 46.2%. None of the patients in blast crisis had CCR or CMR. Several side effects were reported during the treatment. However, among them there was not the most common side effect reported in other studies. Limb muscle and bone pains (20%) were the most frequently reported side effects in our group of patients.</p><p>Conclusions. Imatinib has be found to be most effective in chronic and accelerated phase of CML. However, there is still not enough data about its long-term use and prognosis. For the time being, PBSCT remains the only proven curative treatment of CML.<br /><br /></p

Electro-coagulation of reactive textile dyes and textile wastewater

International audienc

Effet des nitrites sur les émissions de protoxyde d'azote issues d'une boue activée dénitrifiante

International audienceLaboratory-scale experiments were conducted to examine the N2O emission during the denitrification process. For each of the 6 runs carried out, synthetic effluent was fed in a 10 l batch mixed liquor to investigate the effect of nitrite on N2O emission and Helium was continuously bubbled through the reactor at constant rate (0.12 l/min) to favour N2O transfer and detection. An increasing COD/NO3−-N influent ratio from 3 to 7 was firstly applied (runs 1-3). Secondly, NO2− pulse additions were performed during run 4 and 5 (10 and 20 mg N/l, respectively). Finally, the reactor was fed with influent containing both NO2− and NO3−. We showed that N2O emission was detected shortly after NO2− accumulation, few minutes after the substrate feeding. The highest emission occurred at the lower COD/NO3−-N ratio (=3) and at the higher NO2− addition (20 mg N/l). In addition, the higher nitrogen conversion to N2O gas (14.4%) was obtained with an influent containing initially both NO2− and NO3−. Our results suggest a direct effect of the NO2− concentration on the N2O emission. We have also confirmed the inhibitory effect of NO2− concentration on N2O reduction

Effet des nitrites sur les émissions de protoxyde d'azote issues d'une boue activée dénitrifiante

International audienceLaboratory-scale experiments were conducted to examine the N2O emission during the denitrification process. For each of the 6 runs carried out, synthetic effluent was fed in a 10 l batch mixed liquor to investigate the effect of nitrite on N2O emission and Helium was continuously bubbled through the reactor at constant rate (0.12 l/min) to favour N2O transfer and detection. An increasing COD/NO3−-N influent ratio from 3 to 7 was firstly applied (runs 1-3). Secondly, NO2− pulse additions were performed during run 4 and 5 (10 and 20 mg N/l, respectively). Finally, the reactor was fed with influent containing both NO2− and NO3−. We showed that N2O emission was detected shortly after NO2− accumulation, few minutes after the substrate feeding. The highest emission occurred at the lower COD/NO3−-N ratio (=3) and at the higher NO2− addition (20 mg N/l). In addition, the higher nitrogen conversion to N2O gas (14.4%) was obtained with an influent containing initially both NO2− and NO3−. Our results suggest a direct effect of the NO2− concentration on the N2O emission. We have also confirmed the inhibitory effect of NO2− concentration on N2O reduction

Nitrite effect on nitrous oxide emission from denitrifying activated sludge

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Treatment of wastewater dyeing agent by photocatalytic process in solar reactor

The photocatalytic decolorization of industrial textile dyes has been studied. The treatment was carried out on a solar reactor consisting in a flat active plane, tilted so as to face the sun and to allow the trickling of the water to be treated. Alternatively the reactor could be irradiated by an artificial source. After checking the system using salicylic acid, a conventional model molecule, the photocatalytic decolorization of Orange II, Yellow Drimarene, and Black Drimarene dyes was investigated. Artificial and solar irradiation gave comparable results although the heating by the sun reduced the amount of adsorption. The kinetics agrees with the Langmuir-Hinshelwood model and a discrepancy between adsorption constants deduced from the kinetic and adsorption experiments was interpreted by considering various types of adsorption sites. Orange II and Drimarene dyes decolorization kinetics are opposite limiting cases of the above model, as being of order 0 and 1 with respect to the dye, respectively

Treatment ofWastewater Dyeing Agent by Photocatalytic Process in Solar Reactor.

International audienceThe photocatalytic decolorization of industrial textile dyes has been studied. The treatment was carried out on a solar reactor consisting in a flat active plane, tilted so as to face the sun and to allow the trickling of the water to be treated. Alternatively the reactor could be irradiated by an artificial source. After checking the system using salicylic acid, a conventional model molecule, the photocatalytic decolorization of Orange II, Yellow Drimarene, and Black Drimarene dyes was investigated. Artificial and solar irradiation gave comparable results although the heating by the sun reduced the amount of adsorption. The kinetics agrees with the Langmuir-Hinshelwood model and a discrepancy between adsorption constants deduced from the kinetic and adsorption experiments was interpreted by considering various types of adsorption sites. Orange II andDrimarene dyes decolorization kinetics are opposite limiting cases of the above model, as being of order 0 and 1 with respect to the dye, respectively