The Impact of Advanced Wastewater Treatment Technologies and Wastewater Strength on the Energy Consumption of Large Wastewater Treatment Plants

Wastewater treatment is an energy intensive process often requiring the use of advanced treatment technologies. Stricter effluent standards have resulted in an increase in the number of wastewater treatment plants (WWTPs) with advanced treatment over time. Accordingly, associated energy consumption has also increased. Concerns about lowering operating costs for WWTPs and reducing associated greenhouse gas generation present an incentive to investigate energy use in WWTPs. This research investigated the impact of wastewater strength and the introduction of advanced treatment technologies, to replace traditional technologies on energy use to treat wastewater in WWTPs. Major unit processes were designed for a 100 MGD plant and variables controlling energy were identified and used to compute energy consumption. Except for primary clarification and plate and frame press dewatering, energy consumption computed using fundamental equations are within values in the literature. Results show that energy consumption for dissolved air flotation thickeners, centrifuges, gravity thickeners, and aeration basins are heavily influence by wastewater strength. Secondary treatment and tertiary treatment require a significant amount of energy. Secondary treatment requires 104 times the energy of preliminary treatment, 17 times the energy of solids processing, and 2.5 times the energy of tertiary treatment. Secondary treatment requires 41 times the energy of preliminary treatment, and 7 times the energy of solids processing. The results of this research provide a means of estimating energy consumption in the design and operation phase of a WWTP. By using the fundamental equations and methodology presented, alternative technologies can be compared or targeted for future energy savings implementation. Limitations of the methodology include design assumptions having to be made carefully, as well as assumptions of motor and equipment efficiencies

Energy Consumption in Large Wastewater Treatment Plants as a Function of Wastewater Strength

Wastewater treatment (WWT) is an energy-intensive process. Strict standards for discharge often require energy intensive advanced treatment technologies. As a result, the number of plants using advanced treatment has increased (Figure 1). Rising energy costs and concerns about greenhouse gas generation present a major incentive for tracking energy usage of WWT. Energy usage in plant, for instance, typically represents 18 to 30% of the operational budget. Water efficient fixtures are also increasing loadings of organic matter to plants while lowering or maintaining overall liquid flow. The increased loadings have a significant impact on energy consumption. Previous work has focused primarily on aeration consumption for activated sludge rather than a plant as whole. There are very few studies that show energy requirements on a plant-wide scale with the Water Environment Federation (WEF) being one major source. This research presents a general methodology for tracking energy usage in a plant with regards to wastewater strength. It is anticipated that this research will provide a tool for designers and owners who wish to predict their energy impact before construction of a new plant or before implementing a new process on an existing plant

LIMIT CYCLE DYNAMICS ACROSS ELITE MALE ARTISTIC GYMNASTS

Biological systems described by their attractor dynamics provide a method to understand the fundamental characteristics of skilled movement. Here the limit cycle dynamics of the longswing were investigated across tiers of elite men’s gymnasts. Senior, junior and development elite gymnasts (N=21) performed three trials of eight consecutive longswings on high bar. Limit cycle analysis revealed a more symmetrical angular velocity of the centre of mass about the bar trajectory in phase space, higher recurrence, lower correlation dimension and lower variability for senior gymnasts suggesting a more deterministic, efficient and predictive technique. The addition of non-linear dynamics to traditional biomechanics offers complementary theoretical and coaching knowledge to movement coordination, control and skill

Investigation of Integrated Subsurface Processing of Landfill Gas and Carbon Sequestration, Johnson County, Kansas

The Johnson County Landfill in Shawnee, KS is operated by Deffenbaugh Industries and serves much of metropolitan Kansas City. Refuse, which is dumped in large plastic-underlined trash cells covering several acres, is covered over with shale shortly after burial. The landfill waste, once it fills the cell, is then drilled by Kansas City LFG, so that the gas generated by anaerobic decomposition of the refuse can be harvested. Production of raw landfill gas from the Johnson County landfill comes from 150 wells. Daily production is approximately 2.2 to 2.5 mmcf, of which approximately 50% is methane and 50% is carbon dioxide and NMVOCs (non-methane volatile organic compounds). Heating value is approximately 550 BTU/scf. A upgrading plant, utilizing an amine process, rejects the carbon dioxide and NMVOCs, and upgrades the gas to pipeline quality (i.e., nominally a heating value >950 BTU/scf). The gas is sold to a pipeline adjacent to the landfill. With coal-bearing strata underlying the landfill, and carbon dioxide a major effluent gas derived from the upgrading process, the Johnson County Landfill is potentially an ideal setting to study the feasibility of injecting the effluent gas in the coals for both enhanced coalbed methane recovery and carbon sequestration. To these ends, coals below the landfill were cored and then were analyzed for their thickness and sorbed gas content, which ranged up to 79 scf/ton. Assuming 1 1/2 square miles of land (960 acres) at the Johnson County Landfill can be utilized for coalbed and shale gas recovery, the total amount of in-place gas calculates to 946,200 mcf, or 946.2 mmcf, or 0.95 bcf (i.e., 985.6 mcf/acre X 960 acres). Assuming that carbon dioxide can be imbibed by the coals and shales on a 2:1 ratio compared to the gas that was originally present, then 1682 to 1720 days (4.6 to 4.7 years) of landfill carbon dioxide production can be sequestered by the coals and shales immediately under the landfill. Three coal--the Bevier, Fleming, and Mulberry coals--are the major coals of sufficient thickness (nominally >1-foot) that can imbibe carbon dioxide gas with an enhanced coalbed injection. Comparison of the adsorption gas content of coals to the gas desorbed from the coals shows that the degree of saturation decreases with depth for the coals

DYNAMICS OF A CYCLIC TASK BEFORE AND AFTER A CHANGE IN TASK CONSTRAINT: HORIZONTAL BAR LONGSWING

Returning to a consistent technique after a change in skill allows gymnasts to improve routine fluidity. This study investigates the limit cycle dynamics of the mass centre (CM) after a variation in task constraint during the horizontal bar longswing (LS). Gymnasts (n=12) from 3 different age categories completed 3 x 8 consecutive LS with LS four and five as accelerated LS. Senior gymnasts presented the most consistent limit cycle trajectory and lowest correlation dimension (CD) post- compared to pre- task constraint. Senior gymnasts displayed significantly lower CD post- constraint compared to both junior (p = .016) and development gymnasts (p\u3c .001). The increased proficiency attributed to senior gymnasts appears to increase the stability features of the LS limit cycle of the CM angular velocity after an imposed task constraint which may indicate readiness to progress to more complex horizontal bar skills

Borrelia burgdorferi Adhere to Blood Vessels in the Dura Mater and are Associated with Increased Meningeal T Cells during Murine Disseminated Borreliosis

Borrelia burgdorferi, the causative agent of Lyme disease, is a vector-borne bacterial infection that is transmitted through the bite of an infected tick. If not treated with antibiotics during the early stages of infection, disseminated infection can spread to the central nervous system (CNS). In non-human primates (NHPs) it has been demonstrated that the leptomeninges are among the tissues colonized by B. burgdorferi spirochetes. Although the NHP model parallels aspects of human borreliosis, a small rodent model would be ideal to study the trafficking of spirochetes and immune cells into the CNS. Here we show that during early and late disseminated infection, B. burgdorferi infects the meninges of intradermally infected mice, and is associated with concurrent increases in meningeal T cells. We found that the dura mater was consistently culture positive for spirochetes in transcardially perfused mice, independent of the strain of B. burgdorferi used. Within the dura mater, spirochetes were preferentially located in vascular regions, but were also present in perivascular, and extravascular regions, as late as 75 days post-infection. At the same end-point, we observed significant increases in the number of CD3+ T cells within the pia and dura mater, as compared to controls. Flow cytometric analysis of leukocytes isolated from the dura mater revealed that CD3+ cell populations were comprised of both CD4 and CD8 T cells. Overall, our data demonstrate that similarly to infection in peripheral tissues, spirochetes adhere to the dura mater during disseminated infection, and are associated with increases in the number of meningeal T cells. Collectively, our results demonstrate that there are aspects of B. burgdorferi meningeal infection that can be modelled in laboratory mice, suggesting that mice may be useful for elucidating mechanisms of meningeal pathogenesis by B. burgdorferi

Coupling angle variability in healthy and patellofemoral pain runners

Background Patellofemoral pain is hypothesized to result in less joint coordination variability. The ability to relate coordination variability to patellofemoral pain pathology could have many clinical uses; however, evidence to support its clinical application is lacking. The aim was to determine if vector coding's coupling angle variability, as a measure of joint coordination variability, was less for runners with patellofemoral pain than healthy controls as is commonly postulated. Methods Nineteen female recreational runners with patellofemoral pain and eleven healthy controls performed a treadmill acclimation protocol then ran at a self-selected pace for 15 min. 3-D kinematics, force plate kinetics, knee pain and rating of perceived exertion were recorded each minute. Data were selected for the: pain group at the highest pain reached (pain � 3/10) in a non-exerted state (exertion < 14/20), and; non-exerted healthy group from the eleventh minute. Coupling angle variability was calculated over several portions of the stride for six knee-ankle combinations during five non-consecutive strides. Findings 46 of 48 coupling angle variability measures were greater for the pain group, with 7 significantly greater (P <.05). Interpretation These findings oppose the theory that less coupling angle variability is indicative of a pathological coordinate state during running. Greater coupling angle variability may be characteristic of patellofemoral pain in female treadmill running when a larger threshold of pain is reached than previously observed. A predictable and directional response of coupling angle variability measures in relation to knee pathology is not yet clear and requires further investigation prior to considerations for clinical utility. © 2013 Elsevier Ltd

Attractor dynamics of elite performance: the high bar longswing

Combining biomechanics and motor control, the aim of this study was to investigate the limit cycle dynamics during the high bar longswing across the UK elite gymnastics pathway age groupings. Senior, junior and development gymnasts (N = 30) performed three sets of eight consecutive longswings on the high bar. The centre of mass motion was examined through Poincaré plots and recurrence quantification analysis exploring the limit cycle dynamics of the longswing. Close to one-dimensional limit cycles were displayed for the senior (correlation dimension (CD) = 1.17 ± .08), junior (CD = 1.26 ± .08) and development gymnasts (CD = 1.33 ± .14). Senior elite gymnasts displayed increased recurrence characteristics in addition to longer longswing duration (p < .01) and lower radial angular velocity of the mass centre (p < .01). All groups of gymnasts had highly recurrent and predictable limit cycle characteristics. The findings of this research support the postulation that the further practice, experience and individual development associated with the senior gymnasts contribute to the refinement of the longswing from a nonlinear dynamics perspective. These findings support the idea of functional task decomposition informing the understanding of skill and influencing coaches’ decisions around skill development and physical preparation

Stature and sibship: historical evidence

This paper examines historical evidence for a quality–quantity trade-off between sibship size and height as an indicator of health. The existing literature has focused more on education than on health and it has produced mixed results. Historical evidence is limited by the lack of household-level data with which to link an individual’s height with his or her childhood circumstances. Nevertheless a few recent studies have shed light on this issue. Evidence for children in interwar Britain and for soldiers born in the 1890s who enlisted in the British army at the time of World War I is reviewed in detail. Both studies support the idea of a significant trade-off, partly due to income dilution and partly because, in these settings, large families were a conduit for infection. Evidence from country-level time series is consistent with this view. The fertility decline that began in the late nineteenth century made a modest but nevertheless significant contribution to the overall increase in heights during the following half-century