A simulation-based optimisation approach to control nitrogen discharge by activated sludge under winter seasonal peak load

Wastewater treatment systems located in cold areas are under increasing pressure to remove nitrogen from their wastewater. As constraining operating conditions like dramatic influent load increases exacerbated by cold temperatures can occur (e.g. winter tourist resorts, ski resorts), specific technical treatment solutions have to be adapted. The objective of this research is to determine the maximal magnitude of load variation which can be applied in winter to an activated sludge treatment system. It aims at analyzing the effects of high influent load variations on the nitrogen removal capacity. Two operating strategies are investigated by dynamic simulations performed with ASM1: • A fixed aeration tank volume with a fixed MLTSS concentration • A variable aeration volume tank with a variable MLTSS concentration It is demonstrated that the variable aeration tank volume strategy is more efficient than the fixed volume strategy to face long-term peak load. To meet an effluent ammonia nitrate concentration of below 10 mgN·ℓ-1, a maximum input load increase by a factor 2 should be applied with the first strategy; whereas with the second strategy a load increase by a factor 4 should be applied (with constant oxygen presence time). If the oxygen presence time can be increased by 50% the maximum input load increase could reach a factor 6. Water SA Vol.32 (4) 2006: pp.561-56

Organic Foulants Characteristics in Membrane Bioreactor

A laboratory scale side stream membrane bioreactor system with flat sheet membrane was operated for 5–days run at three different aeration rates (100, 200 and 300 L/h). The organic foulants deposited on the membrane surface was studied after extraction with 5% NaOH solution using three spectroscopic techniques. The IR spectra showed no distinct similarity in peaks among the three. The fluorescence spectra showed increase of soluble microbial products in foulant with decrease of aeration rate. This was supported by the size exclusion chromatography in which biopolymers concentration in fouling decreased with increasing aeration rate

Degree of urbanization and gender differences in substance use among Slovak adolescents

Substance use among adolescents varies with gender and between countries. Urbanization may contribute to this. The aim of our study is to explore the association between the degree of urbanization and gender differences in adolescent smoking, binge drinking, and cannabis use. A cross-sectional questionnaire survey of Slovak adolescents was used (N = 3,493; mean age = 14.33), stratified by degree of urbanization. The effects of gender and urbanization of the area and their interaction on substance use (smoking, binge drinking, and cannabis) were analyzed using a logistic regression model adjusted for age. Gender and area and their interaction had statistically significant (p <0.01) associations with substance use. The lower the urbanization of the area, the less riskily females behaved. An exception was found in the case of binge drinking where the results of the interaction of gender and degree of urbanization were not significant for the second least urbanized area. Prevalence rate of substance use among girls increased along with an increasing degree of urbanization, while the prevalence rate of substance use among boys remained constant

Swimming in a Sea of Shame: Incorporating Emotions into Explanations of Institutional Reproduction and Change

We theorize the role in institutional processes of what we call the shame nexus, a set of shame-related constructs: felt shame, systemic shame, sense of shame, and episodic shaming. As a discrete emotion, felt shame signals to a person that a social bond is at risk and catalyzes a fundamental motivation to preserve valued bonds. We conceptualize systemic shame as a form of disciplinary power, animated by persons’ sense of shame, a mechanism of ongoing intersubjective surveillance and self-regulation. We theorize how the duo of the sense of shame and systemic shame drives the self-regulation that underpins persons’ conformity to institutional prescriptions and institutional reproduction. We conceptualize episodic shaming as a form of juridical power used by institutional guardians to elicit renewed conformity and reassert institutional prescriptions. We also explain how episodic shaming may have unintended effects, including institutional disruption and recreation, when it triggers sensemaking among targets and observers that can lead to the reassessment of the appropriateness of institutional prescriptions or the value of social bonds. We link the shame nexus to three broad categories of institutional work

Predictors of binge drinking in adolescents: ultimate and distal factors - a representative study

<p>Abstract</p> <p>Background</p> <p>As epidemiological surveys have shown, binge drinking is a constant and wide-spread problem behavior in adolescents. It is not rare to find that more than half of all adolescents engage in this behavior when assessing only the last 4 weeks of time independent of the urbanity of the region they live in. There have been several reviews on predictors of substance consumption in adolescents in general, but there has been less high quality research on predictors of binge drinking, and most studies have not been theoretically based. The current study aimed to analyze the ultimate and distal factors predicting substance consumption according to Petraitis' theory of triadic influence. We assessed the predictive value of these factors with respect to binge drinking in German adolescents, including the identification of influence direction.</p> <p>Methods</p> <p>In the years 2007/2008, a representative written survey of N = 44,610 students in the 9^thgrade of different school types in Germany was carried out (net sample). The return rate of questionnaires was 88% regarding all students whose teachers or school directors had agreed to participate in the study. In this survey, prevalence of binge drinking was investigated as well as potential predictors from the social/interpersonal, the attitudinal/environmental, and the intrapersonal fields (3 factors of Petraitis). In a multivariate logistic regression analysis, these variables were included after testing for multicollinearity in order to assess their ability to predict binge drinking.</p> <p>Results</p> <p>Prevalence of binge drinking in the last 30 days was 52.3% for the surveyed adolescents with a higher prevalence for boys (56.9%) than for girls (47.5%). The two most influential factors found to protect against binge drinking with <it>p </it>< .001 were low economic status and importance of religion. The four most relevant risk factors for binge drinking (<it>p </it>< .001) were life-time prevalence of school absenteeism/truancy, academic failure, suicidal thoughts, and violence at school in the form of aggressive behavior of teachers. The model of Petraitis was partly confirmed for Binge Drinking in German adolescents and the direction of influence factors was clarified.</p> <p>Conclusions</p> <p>Whereas some of the risk and protective factors for binge drinking are not surprising since they are known for substance abuse in general, there are two points that could be targeted in interventions that do not focus on adolescents alone: (a) training teachers in positive, reassuring behavior and constructive criticism and (b) a focus on high risk adolescents either because they have a lack of coping strategies when in a negative mood or because of their low academic achievement in combination with absenteeism from school.</p

Evaluating the drivers of and obstacles to the willingness to use cognitive enhancement drugs: the influence of drug characteristics, social environment, and personal characteristics

Sattler S, Mehlkop G, Graeff P, Sauer C. Evaluating the drivers of and obstacles to the willingness to use cognitive enhancement drugs: the influence of drug characteristics, social environment, and personal characteristics. Substance Abuse Treatment, Prevention, and Policy. 2014;9(1): 8.Background The use of cognitive enhancement (CE) by means of pharmaceutical agents has been the subject of intense debate both among scientists and in the media. This study investigates several drivers of and obstacles to the willingness to use prescription drugs non-medically for augmenting brain capacity. Methods We conducted a web-based study among 2,877 students from randomly selected disciplines at German universities. Using a factorial survey, respondents expressed their willingness to take various hypothetical CE-drugs; the drugs were described by five experimentally varied characteristics and the social environment by three varied characteristics. Personal characteristics and demographic controls were also measured. Results We found that 65.3% of the respondents staunchly refused to use CE-drugs. The results of a multivariate negative binomial regression indicated that respondents’ willingness to use CE-drugs increased if the potential drugs promised a significant augmentation of mental capacity and a high probability of achieving this augmentation. Willingness decreased when there was a high probability of side effects and a high price. Prevalent CE-drug use among peers increased willingness, whereas a social environment that strongly disapproved of these drugs decreased it. Regarding the respondents’ characteristics, pronounced academic procrastination, high cognitive test anxiety, low intrinsic motivation, low internalization of social norms against CE-drug use, and past experiences with CE-drugs increased willingness. The potential severity of side effects, social recommendations about using CE-drugs, risk preferences, and competencies had no measured effects upon willingness. Conclusions These findings contribute to understanding factors that influence the willingness to use CE-drugs. They support the assumption of instrumental drug use and may contribute to the development of prevention, policy, and educational strategies

Predicting norm enforcement: the individual and joint predictive power of economic preferences, personality, and self-control

This paper explores the individual and joint predictive power of concepts from economics, psychology, and criminology for individual norm enforcement behavior. More specifically, we consider economic preferences (patience and attitudes towards risk), personality traits from psychology (Big Five and locus of control), and a self-control scale from criminology. Using survey data, we show that the various concepts complement each other in predicting self-reported norm enforcement behavior. The most significant predictors stem from all three disciplines: stronger risk aversion, conscientiousness and neuroticism as well as higher levels of self-control increase an individual's willingness to enforce norms. Taking a broader perspective, our results illustrate that integrating concepts from different disciplines may enhance our understanding of heterogeneity in individual behavior

Épisodes d’inactivité et revenus criminels dans une trajectoire de délinquance

L’instabilité de l’activité criminelle dans le temps est déjà bien documentée. On connaît toutefois peu les circonstances qui expliquent ces variations à court terme. Une meilleure connaissance de ces facteurs est souhaitable puisqu’il est possible que les transitions et les changements à court terme précèdent les points tournants des carrières criminelles. Les conditions qui rendent compte d’une interruption temporaire des activités peuvent, par exemple, contribuer à expliquer un désistement définitif. L’étude se fonde sur les trajectoires de 172 délinquants impliqués dans des crimes à but lucratif et analyse les variations mensuelles de leurs revenus criminels ainsi que les épisodes d’inactivité criminelle à l’intérieur d’une période fenêtre de 36 mois. La méthode des calendriers d’histoire de vie combinée aux modèles hiérarchiques permet d’examiner conjointement le rôle de facteurs statiques (les caractéristiques individuelles des sujets) et dynamiques (les circonstances de vie). Les résultats mettent en évidence l’importance des événements qui marquent le style de vie des délinquants et des paramètres qui caractérisent l’engagement criminel dans la compréhension des variations dans les trajectoires à l’étude. Ils soulignent également l’importance de la finalité derrière les activités criminelles pour expliquer la décision des délinquants de cesser temporaire leurs activités illicites