Strategies to optimize phosphate removal from industrial anaerobic effluents by magnesium ammonium phosphate (MAP) production

BACKGROUND: Owing to more stringent phosphate discharge requirements and the increasing prices of fertilizers, beneficial recovery and reuse of phosphate from industrial anaerobic effluents is becoming an important issue. Phosphate recovery by struvite or magnesium ammonium phosphate (MAP) permits its recycling in the fertilizer industry because struvite is a valuable slow release fertilizer. Two different approaches to MAP crystallization depending on initial levels of phosphate in the wastewaters were tested and compared. RESULTS: For low‐phosphate‐containing anaerobic effluents (<30 mg PO₄^3?‐P L^?1), a novel approach using ureolytic induced MAP formation with MgO addition appeared to be suitable. The residual phosphate concentrations in the effluent ranged from 5 to 7 mg PO₄^3?‐P L^?1 and the separated matter contained residual amounts of Mg(OH)₂. High‐phosphate‐containing anaerobic effluents (100 to 120 mg PO₄^3?‐P L^?1) were treated efficiently using air stripping combined with MgCl₂ and NaOH reagents, yielding residual phosphate levels of 8 to 15 mg PO₄^3?‐P L^?1 and spherical pure MAP crystals of 0.5 to 2 mm. CONCLUSION: Results show that depending on the initial phosphate concentrations in the wastewaters and the ammonium and magnesium levels, the strategy selected for struvite crystallization is a determinative factor in achieving a cost effective technology. Copyright © 2008 Society of Chemical Industry     

Combining Futures and Spot Markets: A Hybrid Market Approach to Economic Grid Resource Management

Economic forms of resource management in which users can express their valuations for service, offer new possibilities for optimizing resource allocations in Grids. If users are to correctly express these valuations, quality of service guarantees need to be given with respect to the turnaround time of their workloads. Market mechanisms that support bidding and allocations in future time are crucial for delivering such guarantees. To deal with the significant delays that these mechanisms introduce in the allocation process, we present a hybrid market approach in which a low-latency spot market coexists with a higher latency futures market. Based on simulated market scenarios, we show how this combination can significantly increase the total value realized by the Grid infrastructure. We also demonstrate how providers can react to price dynamics in such a hybrid market setting.     

Innovation in traditional food products in Europe: Do sector innovation activities match consumers’ acceptance?

Traditional food products are subject to an increased interest in Europe. Innovations, though controversial in the context of traditional food, are essential to maximally cope with this opportunity. So far, only few studies have concentrated on innovation in the traditional food sector. In this paper sector and consumer data are combined in order to validate to what extent innovations in the traditional food sector match with consumers’ acceptance. Sector innovations were explored through 270 interviews, covering 90 traditional food chains in three European countries (Belgium, Italy and Hungary). Consumers’ innovation acceptance was investigated using a quantitative survey approach with 2429 respondents in Belgium, Italy and Poland. In general, both the sector and the consumers were open towards innovations in traditional food products. In addition, the innovation activities of the sector were matching well with the innovations accepted by consumers. Throughout, preserving the traditional character of the food was stressed as a prerequisite for innovations in traditional food products.     

Longitudinal spillover effects of conflict resolution styles between adolescent-parent relationships and adolescent friendships.

This study longitudinally investigated spillover effects of conflict resolution styles in adolescent-parent relationships and adolescent friendships. Questionnaires about conflict resolution styles with parents and best friends were completed by adolescents from two age cohorts: 559 early adolescents (mean age 13.4) and 327 middle adolescents (mean age 17.7). Path analyses on two waves, with a three-year interval, indicated that in the early-to-middle adolescent group positive problem solving and conflict engagement spilled over from adolescent-parent relationships to adolescent friendships and not from adolescent friendships to adolescent-parent relationships. In the middle-to-late adolescent group, we found bidirectional spillover effects for these two conflict resolution styles. For withdrawal, we found bidirectional spillover effects in both cohorts. This study showed that both parents and friends set the stage for exercising and learning conflict resolution styles and thereby shape adolescents' future conflict behavior. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Bidirectional links and concurrent development of parent-child relationships and boys' offending behavior.

This study examined different types of longitudinal associations (i.e., directional links and overlapping developmental changes) between children's delinquency and the quality of parent–child relationships from middle childhood to late adolescence. We used 10-wave interview data of 503 boys, their primary caregivers, and their teachers. Our first aim was to unravel the direction of effects between parent–child relationships and children's offending. Cross-lagged panel models revealed bidirectional links over time between poorer quality parent–child relationships and boys' offending across late childhood (age 7–10), early adolescence (age 10–13) and middle adolescence (age 13–16). Second, we examined the associations between mean changes in delinquency, on the one hand, and mean changes in relationship quality, on the other hand. Although parent–child relationships improved during childhood, their quality decreased in early adolescence and remained stable in middle adolescence. Delinquency increased only in middle adolescence. In five out of six models, the slope factors of relationship quality and offending were strongly correlated, indicating that stronger increases in delinquency were associated with stronger decreases in parent–child relationship quality across childhood, early adolescence, and middle adolescence. The discussion focuses on the theoretical implications of these two types of longitudinal associations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Evaluating expectations about negative emotional states of aggressive boys using Bayesian model selection.

Researchers often have expectations about the research outcomes in regard to inequality constraints between, e.g., group means. Consider the example of researchers who investigated the effects of inducing a negative emotional state in aggressive boys. It was expected that highly aggressive boys would, on average, score higher on aggressive responses toward other peers than moderately aggressive boys, who would in turn score higher than nonaggressive boys. In most cases, null hypothesis testing is used to evaluate such hypotheses. We show, however, that hypotheses formulated using inequality constraints between the group means are generally not evaluated properly. The wrong hypotheses are tested, i.e.. the null hypothesis that group means are equal. In this article, we propose an innovative solution to these above-mentioned issues using Bayesian model selection, which we illustrate using a case study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tracing enteric viruses in the European berry fruit supply chain

In recent years, numerous foodborne outbreaks due to consumption of berry fruit contaminated by human enteric viruses have been reported. This European multinational study investigated possible contamination routes by monitoring the entire food chain for a panel of human and animal enteric viruses.