Mechanisms for Reduced Excess Sludge Production in the Cannibal Process

Reducing excess sludge production is increasingly attractive as a result of rising costs and constraints with respect to sludge treatment and disposal. A technology in which the mechanisms remain not well understood is the Cannibal process, for which very low sludge yields have been reported. The objective of this work was to use modeling as a means to characterize excess sludge production at a full-scale Cannibal facility by providing a long sludge retention time and removing trash and grit by physical processes. The facility was characterized by using its historical data, from discussion with the staff and by conducting a sampling campaign to prepare a solids inventory and an overall mass balance. At the evaluated sludge retention time of 400 days, the sum of the daily loss of suspended solids to the effluent and of the waste activated sludge solids contributed approximately equally to the sum of solids that are wasted daily as trash and grit from the solids separation module. The overall sludge production was estimated to be 0.14 g total suspended solids produced/g chemical oxygen demand removed. The essential functions of the Cannibal process for the reduction of sludge production appear to be to remove trash and grit from the sludge by physical processes of microscreening and hydrocycloning, respectively, and to provide a long sludge retention time, which allows the slow degradation of the “unbiodegradable” influent particulate organics (XU,Inf) and the endogenous residue (XE). The high energy demand of 1.6 kWh/m3 of treated wastewater at the studied facility limits the niche of the Cannibal process to small- to medium-sized facilities in which sludge disposal costs are high but electricity costs are low

Sleep deprivation reveals altered brain perfusion patterns in somnambulism

BACKGROUND: Despite its high prevalence, relatively little is known about the pathophysiology of somnambulism. Increasing evidence indicates that somnambulism is associated with functional abnormalities during wakefulness and that sleep deprivation constitutes an important drive that facilitates sleepwalking in predisposed patients. Here, we studied the neural mechanisms associated with somnambulism using Single Photon Emission Computed Tomography (SPECT) with 99mTc-Ethylene Cysteinate Dimer (ECD), during wakefulness and after sleep deprivation. METHODS: Ten adult sleepwalkers and twelve controls with normal sleep were scanned using 99mTc-ECD SPECT in morning wakefulness after a full night of sleep. Eight of the sleepwalkers and nine of the controls were also scanned during wakefulness after a night of total sleep deprivation. Between-group comparisons of regional cerebral blood flow (rCBF) were performed to characterize brain activity patterns during wakefulness in sleepwalkers. RESULTS: During wakefulness following a night of total sleep deprivation, rCBF was decreased bilaterally in the inferior temporal gyrus in sleepwalkers compared to controls. CONCLUSIONS: Functional neural abnormalities can be observed during wakefulness in somnambulism, particularly after sleep deprivation and in the inferior temporal cortex. Sleep deprivation thus not only facilitates the occurrence of sleepwalking episodes, but also uncovers patterns of neural dysfunction that characterize sleepwalkers during wakefulness

Compact secondary treatment train combining a lab-scale moving bed biofilm reactor and enhanced flotation processes

High-rate wastewater processes are receiving a renewed interest to obtain energy positive/efficient water resource recovery facilities. An innovative treatment train combining a high-rate moving bed biofilm reactor (HR-MBBR) with an enhanced flotation process was studied. The two objectives of this work were 1) to maximize the conversion of soluble organics to particulate matter in an HR-MBBR and 2) to maximize the particulate matter recovery from the HR-MBBR effluent by green chemicals to enhance biogas production by anaerobic digestion. To achieve these objectives, lab-scale MBBRs fed with synthetic soluble wastewater were operated at organic loading rates (OLRs) between 4 and 34 kg COD m−3 reactor d−1 corresponding to hydraulic retention times (HRTs) between 6 and 54 min. Colloidal and soluble chemical oxygen demand (COD) removal efficiency in the HR-MBBR increased with HRT to reach a plateau of 85% at an HRT longer than 27 min. Carrier clogging observed at an OLR higher than 16 kg COD m−3 d−1 (HRT < 13 min) resulted in about 23% loss in colloidal and soluble COD removal efficiency. Thus, the recommended parameters were between 22 and 37 min and between 6 and 10 kg COD m−3 d−1 for the HRT and the OLR, respectively, to maximize the conversion of soluble organics to particulate matter. Total suspended solids (TSS) recovery of 58–85% and 90–97% were achieved by enhanced flotation using green and unbiodegradable chemicals, respectively, corresponding to a TSS effluent concentration below 14 and 7 mg TSS/L. Among the synthetic polymers tested, a high molecular weight and low charge density cationic polyacrylamide was found to give the best results with less than 2 mg TSS/L in the clarified effluent (97% TSS recovery). Green chemicals, although performing slightly less for solids separation than unbiodegradable chemicals, achieved a mean TSS concentration of 10 ± 3 mg/L in the clarified effluent

Effect of ozonation on anaerobic digestion sludge activity and viability

The effect of ozonation of anaerobic digested sludge on methane production was studied as a means of increasing the capacity of municipal anaerobic digesters. Ozone doses ranging from 0 to 192 mg O3/g sludge COD were evaluated in batch tests with a bench scale ozonation unit. Ozonation initially, and temporarily, reduced biomass viability and acetoclastic methanogenic activity, resulting in an initial lag phase ranging from 0.8 to 10 days. Following this lag phase, ozonation enhanced methane production with an optimal methane yield attained at 86 mg O3/g COD. Under these conditions, the yield of methane and the rate of its formation were 52% and 95% higher, respectively, than those factors measured without ozonation. A required optimal ozone dose could be feasible to improve the anaerobic digestion performance by increasing the methane production potential with a minimum impact on microbial activity; thus, an optimal ozone dose would enable an increase in the capacity of anaerobic digesters

Ozonation of Primary Sludge and Digested Sludge to Increase Methane Production in a Chemically Enhanced Primary Treatment Facility

The purpose of this research was the investigation of the ozonation of sludge as a method to improve anaerobic digestion performance in a chemically enhanced primary treatment facility. Batch tests were conducted to evaluate the effect of ozonation on the physicochemical characteristics of both primary and digested sludge. Then, the performance of semi-continuous anaerobic digesters in combination with ozone treatment was investigated (pre-ozonation and post-ozonation). Ozonation of primary sludge did not increase the soluble COD nor the biodegradable COD, but resulted in the mineralization of a fraction of the organic matter into CO2. However, the ozonation of anaerobic digested sludge resulted in an increase in soluble COD and biodegradable COD and in a small level of mineralization at the dose of 90 mg O3/g COD. Pre-ozonation of primary sludge was not effective in enhancing the performance of the anaerobic digester. The coupling of ozonation and anaerobic digestion by means of the post-ozonation of digested sludge was found to be effective in improving methane production (+16%), for COD removal efficiency and for the dewaterability of anaerobic digesters compared to the control digester

p21WAF1/CIP1 Upregulation through the Stress Granule-Associated Protein CUGBP1 Confers Resistance to Bortezomib-Mediated Apoptosis

p21(WAF1/CIP1) is a well known cyclin-dependent kinase inhibitor induced by various stress stimuli. Depending on the stress applied, p21 upregulation can either promote apoptosis or prevent against apoptotic injury. The stress-mediated induction of p21 involves not only its transcriptional activation but also its posttranscriptional regulation, mainly through stabilization of p21 mRNA levels. We have previously reported that the proteasome inhibitor MG132 induces the stabilization of p21 mRNA, which correlates with the formation of cytoplasmic RNA stress granules. The mechanism underlying p21 mRNA stabilization, however, remains unknown.We identified the stress granules component CUGBP1 as a factor required for p21 mRNA stabilization following treatment with bortezomib ( =  PS-341/Velcade). This peptide boronate inhibitor of the 26S proteasome is very efficient for the treatment of myelomas and other hematological tumors. However, solid tumors are sometimes refractory to bortezomib treatment. We found that depleting CUGBP1 in cancer cells prevents bortezomib-mediated p21 upregulation. FISH experiments combined to mRNA stability assays show that this effect is largely due to a mistargeting of p21 mRNA in stress granules leading to its degradation. Altering the expression of p21 itself, either by depleting CUGBP1 or p21, promotes bortezomib-mediated apoptosis.We propose that one key mechanism by which apoptosis is inhibited upon treatment with chemotherapeutic drugs might involve upregulation of the p21 protein through CUGBP1

La communauté d’apprentissage professionnelle : une démarche favorisant la réussite éducative des élèves doués ?

Cet article présente les résultats d’une recherche visant à mieux comprendre l’apport des communautés d’apprentissage professionnelles (CAP) à l’égard des élèves doués. Les auteurs s’interrogent sur la capacité d’une CAP à identifier les élèves doués, à dépister leurs besoins et à mettre en place les mesures pour y répondre. La recherche, de type exploratoire et qualitatif, a permis de recueillir les représentations de six enseignants d’un district scolaire francophone du Nouveau-Brunswick, soit deux pour chacun des trois ordres d’enseignement. Leurs représentations ont été validées auprès d’un groupe composé d’enseignants ressources. Des entrevues semi-dirigées, une entrevue de groupe et une analyse documentaire ont servi de méthodes et de techniques de recherche. La collecte de données s’est déroulée durant l’année scolaire 2011-2012. Les résultats montrent que les CAP implantées au Nouveau-Brunswick constituent une approche efficiente et efficace pour identifier les élèves à risque, dépister leurs besoins et y répondre. Bien que ces CAP n’aient pas pour mission de prioriser le phénomène de la douance, les stratégies élaborées en CAP ont des retombées positives sur tous les élèves, y compris les élèves doués. La démarche en CAP pourrait néanmoins être revue afin de mieux répondre aux besoins de ces derniers.This article presents the results of a study aiming to better understand the contribution of professional learning communities (PLC) in relation to gifted students. The authors question the ability of a PLC to identify gifted students, to identify their needs, and to implement measures to address them. Exploratory and qualitative research collected the representations of six teachers from a French school district in New Brunswick, two for each of the three levels of teaching. Their representations were validated with a group of resource teachers. Semi-structured interviews, one group interview, and a documentary analysis were used as research techniques and methods. Data was collected during the 2011-2012 school year. The results show that the New Brunswick PLCs have an efficient and effective approach to identifying students at risk, identifying their needs, and responding to them. Although the PLC does not have a mission to prioritize the phenomenon of giftedness, the strategies developed in PLCs have positive impacts on all students, including those who are gifted. Thus, the PLC approach could be reviewed to better meet the needs of gifted students.Este artículo presenta los resultados de una investigación que buscaba comprender más cabalmente el aporte de las comunidades de aprendizaje profesional (CAP) con respecto a los alumnos aventajados. Los autores se cuestionan sobre la capacidad de una CAP para identificar los alumnos aventajados, para descubrir sus necesidades y para instalar las medidas necesarias. La investigación, de tipo exploratorio y cualitativo, permitió recoger las representaciones de seis maestros de un distrito escolar francófono de Nuevo-Brunswick, es decir, dos personas por cada orden de enseñanza. Las representaciones fueron validadas en un grupo compuesto de maestros-expertos. Entrevistas semi-dirigidas, una entrevista de grupo y un análisis documentario fueron los métodos y las técnicas de investigación. La recolección de datos se desarrollo durante el año escolar 2011-2012. Los resultados muestran que las CAP implantadas en Nuevo-Brunswick constituyen una estrategia eficaz y eficiente en la identificación de los alumnos en situación de riesgo, descubrir sus necesidades y solucionarlas. Aunque dichas CAP no tengan por misión priorizar el fenómeno del talento, las estrategias elaboradas en CAP tienen repercusiones positivas sobre todos los alumnos, incluso los alumnos aventajados. Así, el enfoque en CAP podría ser revisado con el fin de ofrecer una respuesta más adecuada a las necesidades de estos últimos