Nitrogen removal assessment through nitrification rates and media biofilm accumulation in an IFAS process demonstration study

An IFAS demonstration study was conducted at the 76,000 m³/day (20MGD) James River Wastewater Treatment Plant (JRTP) located in Newport News, Virginia by converting one fully-aerobic conventional aeration basin with dedicated secondary clarification to a 7041 m³/day (8404 m³/day max month) IFAS train in a modified Ludzack-Ettinger (MLE) configuration. During the study, biomass concentrations on the biofilm carriers were monitored (weekly) as well as nitrogen species concentrations in the IFAS reactor to quantify the nitrogen transformations occurring within the demonstration tank. In a related effort, nitrification kinetics for ammonia and nitrite oxidizing bacteria were monitored on a weekly basis for IFAS media alone, IFAS process mixed liquor without media, and IFAS mixed liquor and media together in an effort to identify the location of nitrification activity (i.e. on the media or in the suspended culture) in the IFAS process. Biomass quantity on the media was generally observed to be inversely related to temperature except during a period when an auxiliary carbon source contaminated with fungi was introduced. Both ammonia oxidizing and nitrite oxidizing bacterial activity were elevated on the carriers compared to the suspended culture (AOB_media: 4.97 mgNOx/gMLSS/hr; AOB_suspended: 1.72 mgNOx/gMLSS/hr; NOB_media: 7.55 mgNOx/gMLSS/hr; NOB_suspended: 0.82 mgNOx/gMLSS/hr) during all periods of the study. In-basin nitrification rates calculated based on nitrogen profiling efforts averaged 0.90 mgNOx/m²/day which was in good agreement with the average of 0.89 mgNOx/m²/day for IFAS mixed liquor and media from batch testing.     

The Early Development of Passive Treatment Systems for Mining-Influenced Water: A North American Perspective

This paper reviews the early history (first 20 years) of passive treatment of mine water, from its beginnings, when it was viewed as a possible way to treat small flows of circumneutral and mildly acidic coal mine drainage, to its use for much larger flows and more contaminated mine water from metal mines. The original concepts of passive treatment have since been modified and used successfully to treat a wide range of mine water quality and quantities, far more than we would have believed possible.

     

Enantioselective Hydrogenation of Ethyl Benzoylformate,from Mechanism and Kinetics to Continuous Reactor Technology

The enantioselective hydrogenation of ethyl benzoylformate over (−)-cinchonidine (CD)-modified Pt/Al₂O₃ catalyst in semi-batch and continuous fixed bed reactors was studied as a function of the modifier concentration and reaction temperature. The kinetic results from the semibatch reactor showed a higher enantioselectivity and lower initial rate as the amount of modifier was increased. The results from the fixed bed reactor demonstrates that continuous enantioselective hydrogenation is possible and that continuous feeding of (−)-CD is needed to maintain a high steady-state enantioselectivity.

     

Macrolevel and Microlevel Frameworks of Experiential Learning Theory in Construction Engineering Education

The experiential learning theory is one of the best-known learning theories in education and has been explored and developed for decades through various studies in higher education. This learning method is expected to provide a significantly better learning environment for engineering subjects, such as construction techniques and design methods and alternatives, which may occur in most of the construction engineering disciplines. Nevertheless, the theory has hardly been used in construction engineering courses. In this study, the authors perform an in-depth review of the learning theory and present a case study, formwork design example, wherein the theory can be explicitly applied in construction engineering education. Research findings reveal students’ responses to the learning theory and lessons learned. Correlation analysis is conducted to explore how students’ performance in learning can be influenced by this learning theory.     

Visual versus kinesthetic mental imagery: Efficacy for the retention and transfer of a closed motor skill in young children.

The main purposes of this study were (a) to compare the effects of mental imagery combined with physical practise and specific physical practise on the retention and transfer of a closed motor skill in young children; (b) to determine the mental imagery (visual vs. kinesthetic), which is the most efficient for retention and transfer of a closed motor skill; and (c) to verify the relationship between movement image vividness and motor performance. As for the secondary purpose, it was to compare the effects of gender on motor learning. Participants (n = 96) were selected from 3 primary schools. These participants were divided into 6 groups and submitted to different experimental conditions. The experimental task required the participants to throw, with the nondominant hand (left hand), a ball toward a target composed of 3 concentric circles. The results demonstrated that performance obtained by the mental imagery (visual or kinesthetic) combined with physical practise group was, during the retention phase, equivalent to that produced by the specific physical practise group but significantly superior during the transfer of closed motor skill. These results showed the potential benefits of mental imagery as a retention strategy intended for motor skills and performance enhancement. Such results could be explained by the similarity of 3 principal functional evidences shared by mental and physical practise: behavioural, central, and peripheral (as suggested by Holmes & Collins, 2001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing, Regulation and Control: shifting education narratives

This paper explores the impact of the 1988 Education Reform Act in England Wales on education ideologies. In particular it considers the changing narratives of the pupil being brought about through profiling, testing and streaming. Using Foucault's notion of 'moral technologies', the paper examines the regulation of pupil behaviour and the construction of pupil identity through systems of classification and grading. This argument is supported by school-based research into the use of testing and profiling by teachers. The paper concludes that the pedagogic aspirations of child centredness and the National Curriculum converge in the everyday practices of primary school teachers.     

Seismic design of outrigger systems using equivalent energy design procedure

An outrigger system is an effective structural scheme that is commonly used in high‐rise construction to increase the stiffness of concrete core walls and to reduce the moment demand within the walls. Despite the on‐going use of outrigger systems around the world, a formal seismic design procedure is yet available. This paper presents an equivalent energy design procedure (EEDP) to design outrigger systems for seismic applications. Three prototype outrigger‐wall buildings of various heights are designed for Vancouver, Canada. Detailed finite element models are developed to assess the seismic performance of the prototype buildings and to assess the safety using the FEMA P695 methodology. The result shows that EEDP is an efficient method to design outrigger systems which results in structures that can achieve sufficient margin of safety against collapse and satisfy multiple performance objectives at different seismic hazard levels.     

Lightweight biometric detection system for human classification using pyroelectric infrared detectors

We use pyroelectric detectors that are differential in nature to detect motion in humans by their heat emissions. Coded Fresnel lens arrays create boundaries that help to localize humans in space as well as to classify the nature of their motion. We design and implement a low-cost biometric tracking system by using off-the-shelf components. We demonstrate two classification methods by using data gathered from sensor clusters of dual-element pyroelectric detectors with coded Fresnel lens arrays. We propose two algorithms for person identification, a more generalized spectral clustering method and a more rigorous example that uses principal component regression to perform a blind classification.     

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Structural and thermodynamic analysis of metal filler incorporations in SiaOb(M)cCd polymer derived ceramics: Ta,Hf, Nb

This work systematically investigates the thermodynamic stability of Si_aO_b(M)_cC_d structures derived from polymeric precursors incorporating metal fillers: Ta, Nb, and Hf, at 1200 and 1500°C. Structural characterization of the polymer derived ceramics (PDCs) employs X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Enthalpies of formation relative to crystalline components (metal oxide, silica, silicon carbide, and graphite) are obtained from thermodynamic measurements by high temperature oxide melt solution calorimetry. The enthalpies of formation (∆H°_{f, comp}) of Ta-1200, Hf-1200, Nb-1200, Ta-1500, Hf-1500, and Nb-1500 specimens are −137.82 ± 9.72, −256.31 ± 8.97, −82.80 ± 9.82, −182.80 ± 7.85, −292.54 ± 9.38, −224.98 ± 9.60 kJ/mol, respectively. Overall incorporation of Hf results in most thermodynamically stable structures at all synthesis temperatures. Si_aO_b(M)_cC_d specimens employing Nb fillers undergo the most stable structural evolution in this temperature range. The results indicate strong thermodynamic drive for carbothermal reduction of metal oxide domains. Incorporation of Ta provides the greatest stabilization of SiO₃C mixed bonding environments. Ultimately, the choice of metal filler influences composition, structural evolution, and thermodynamic stability in PDCs.