Pharmaceuticals and health care products in wastewater effluents: the example of carbamazepine

2003 ◽  
Vol 3 (4) ◽  
pp. 131-137 ◽  
Author(s):  
K. Stamatelatou ◽  
C. Frouda ◽  
M.S. Fountoulakis ◽  
P. Drillia ◽  
M. Kornaros ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Consumption Rate ◽  
Solid Phase ◽  
Organic Content ◽  
Operating Conditions ◽  
Anaerobic Sludge ◽  
Aquatic Environments ◽  
Short Term ◽  
Xenobiotic Compound

Persistence and impact of pharmaceutics in the environment are discussed. The case of carbamazepine (CBZ), a widely used antiepileptic drug detected in rivers, lakes, sludges and even in ground water is examined. CBZ fate was investigated in all possible routes that may follow after it has been discharged to the sewage system: activated sludge, anaerobic digestion sludge, seawater, fresh water and soil. Carbamazepine slowed down, i.e. caused a decrease in the COD consumption rate in the activated sludge process, especially after longer term exposure, while the anaerobic sludge process was unaffected in the operating conditions that were applied. The compound was not degraded under either short term or long term exposure to either aerobic or anaerobic degradation processes. Carbamazepine seemed to biosorb to solid phases (soil, sludge) and this strength of sorption was related to the organic content of the solid phase. These results explain why CBZ is a very persistent xenobiotic compound, as is apparent from its detection in appreciable amounts in various aquatic environments.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

scholarly journals High-temperature short-term and long hardness of sintered compact and porous titanium-siliceous carbide ti3sic2

2004 ◽  
Vol 36 (1) ◽  
pp. 11-20 ◽  
Author(s):  
S.A. Firstov ◽  
E.P. Pechkovsky
Keyword(s):  
High Temperature ◽  
Ternary Compound ◽  
Solid Phase ◽  
Porous Titanium ◽  
Critical Values ◽  
Holding Time ◽  
Short Term ◽  
Sintered Compact ◽  
Temperature Range

The ternary compound of titanium-siliceous carbide Ti3SiC2, one of the representatives of Nan laminates, prepared by solid-phase sintering is investigated in compact and porous (q=0.03-0.41) states. Features of its short-term and long-term hardness (?=10 N) behavior in the temperature range from 20 to 1200?? at a holding time of 1-60 min were studied. It is shown that a temperature of about 700?? and holding time under load of about 10 min are critical values of the indentation procedure that correspond to an intensive decrease of hardness. The presence of porosity results in a decrease in hardness. a deformation scheme of compact and porous titanium-siliceous carbide Ti3SiC2 in the temperature range from 20 to 1200?? is proposed. .

Short-term and long-term effects on carbon storage of pulse feeding on acclimated or unacclimated activated sludge

2011 ◽  
Vol 45 (10) ◽  
pp. 3119-3128 ◽  
Author(s):  
Aslı Seyhan Çığgın ◽  
Derin Orhon ◽  
Simona Rossetti ◽  
Mauro Majone
Keyword(s):  
Activated Sludge ◽  
Carbon Storage ◽  
Long Term Effects ◽  
Short Term

A MULTILEVEL MODELING APPROACH FOR ONLINE LEARNING AND CLASSIFICATION OF COMPLEX TRAJECTORIES FOR VIDEO SURVEILLANCE

2014 ◽  
Vol 28 (06) ◽  
pp. 1455009 ◽  
Author(s):  
GIANCARLO IANNIZZOTTO ◽  
LUCIA LO BELLO
Keyword(s):  
Video Surveillance ◽  
Input Sequence ◽  
Gaussian Mixture ◽  
Operating Conditions ◽  
Complex Motion ◽  
Short Term ◽  
Motion Trajectories ◽  
Complex Trajectories

This paper proposes the Multilevel Gaussian Mixture Model (ML_GMM), a novel algorithm for online, unsupervised modeling of complex motion trajectories which allows for fast and reliable abnormal trajectory detection in video surveillance. The presented approach does not directly deal with target tracking or attribution of an observation to either one or another trajectories belonging to different targets. Instead, it receives as an input a sequence of observations and considers them as produced by a reliable, yet possibly noisy, tracker. As an output, it then produces a labeling of the input sequence, as a "normal" or "abnormal" whole trajectory. The normal and abnormal trajectory domains are learned in an unsupervised fashion during the training phase and can be updated while the classifier is running, thanks to its reduced computational complexity. The novelty of the contribution is twofold. First, ML_GMM is capable of representing short-term, as well as long-term, transitions in a consistent way, thus allowing for accurate representation of long and complex trajectories and their reliable labeling as normal or abnormal. Second, it allows the learning process to be run in parallel with the discrimination process, in order to support adaptability of the model to evolving operating conditions. Experimental results show that ML_GMM outperforms a number of comparable approaches in the literature.

Solubility Modelling of Cements: Implications for Radioactive Waste Immobilisation.

1986 ◽  
Vol 84 ◽  
Author(s):  
F.P. Glasser ◽  
D.E. Macphee ◽  
E.E. Lachowski
Keyword(s):  
Calcium Silicate Hydrate ◽  
Composition Range ◽  
Solid Phase ◽  
Chemical Properties ◽  
Free Energies ◽  
Short Term ◽  
Solubility Products ◽  
Compositional Properties ◽  
Cementitious Systems

AbstractThe suitability of cement matrices for the long-term immobilisation of radionuclides cannot be predicted from short-term experimental data alone, because the chemical properties of cementitious systems change continuously over the repository lifetime. To model such changes is complex, so a stepwise approach has been adopted. A chemically simplified model for the solubility and compositional properties of calcium silicate hydrate gels in the system CaO-SiO2 -H20 was previously developed but has now been extended and improved and is applicable to gels in the wider composition range 0.8 < Ca/Si < 1.7. The effects of silicate speciation in aqueous solution on the formation of the solid phase have been more fully considered and the dissolution equilibrium has been revised. Solubility products and free energies of C-S-H formation have been evaluated and predictive applications of the model are discussed.

Nitrification with Biofilms on Small Suspended Particles in Airlift Reactors

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2207-2211 ◽  
Author(s):  
L. Tijhuis ◽  
M. C. M. van Loosdrecht ◽  
J. J. Heijnen
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Term Effect ◽  
Effect Of Temperature ◽  
Nitrification Rate ◽  
Activated Sludge Process ◽  
Short Term ◽  
Long Term Effect ◽  
N Loading

The development of nitrifying biofilms and short and long term influences on the nitrification process were studied in a Biofilm-Airlift-Suspension-reactor. The studied changes are (i) startup of nitrification reactor at different dilution rates, (ii) the effect of temperature on N-oxidation capacity, (iii) the short term effect of N-loading rate on conversion to determine the nitrification overcapacity and (iv) long term effect of N-loading rate on conversion to determine the maximum nitrification capacity in this reactor system. It is shown that the specific nitrification capacity during start-up is constant, 1 g N/(gorg.mat. d), which is high compared to the activated sludge process. The influence of the temperature on the nitrification rate is much less than can be expected from pure culture experiments. On a short term there is only a small nitrification overcapacity in the reactor. The maximum nitrification rate during these experiments was 6 kg N/(m3 d), which is very high compared to the activated sludge process.

scholarly journals Costs vs. Flexibility of Process Heat Recovery Solutions Considering Short-Term Process Variability and Uncertain Long-Term Development

2021 ◽  
Vol 3 ◽  
Author(s):  
Sofie Marton ◽  
Christian Langner ◽  
Elin Svensson ◽  
Simon Harvey
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Operating Conditions ◽  
Climate Mitigation ◽  
Short Term ◽  
Heat Exchanger Network ◽  
Oil Refineries ◽  
Process Heat ◽  
Operating Points

To significantly decrease fossil carbon emissions from oil refineries, a combination of climate mitigation options will be necessary, with potential options including energy efficiency, carbon capture and storage/utilization, biomass integration and electrification. Since existing refinery processes as well as many of the potential new processes are characterized by large heating demands, but also offer large opportunities for process excess heat recovery, heat integration plays a major role for energy efficient refinery operation after the implementation of such measures. Consequently, the process heat recovery systems should not only be able to handle current operating conditions, but also allow for flexibility towards possible future developments. Evaluation of the flexibility of process heat recovery measures with both these perspectives enables a more accurate screening and selection of alternative process design options. This paper proposes a new approach for assessing the trade-off between total annual cost and potential operating flexibility for the heat exchanger network in short-as well as in long-term perspectives. The flexibility assessment is based on the evaluation of a flexibility ratio (similar to the conventional flexibility index) to determine the range in which operating conditions may vary while at the same time achieving feasible operation. The method is further based on identification of critical operating points to achieve pre-defined flexibility targets. This is followed by optimization of design properties (i.e., heat exchanger areas) such that feasible operation is ensured in the critical operating points and costs are minimized for representative operating conditions. The procedure is repeated for a range of different flexibility targets, resulting in a curve that shows the costs as a function of desired flexibility ratio. The approach is illustrated by an example representing a heat exchanger network retrofit at a large oil refinery. Finally, the paper illustrates a way to evaluate the cost penalty if the retrofit is optimized for one operating point but then operated under changed conditions. Consequently, the presented approach provides knowledge about cost and flexibility towards short-term variations considering also changes in operating conditions due to long-term development.

scholarly journals The effect of alkaline solution seepage on deformation appearances in the soil foundation of engineering structures

2019 ◽  
Keyword(s):  
Alkaline Solution ◽  
Solid Phase ◽  
Soil Layer ◽  
Operating Conditions ◽  
Alkaline Solutions ◽  
Overhead Crane ◽  
Engineering Structures ◽  
Soil Subsidence ◽  
Soil Foundation

Aim. This study aims to analyze the influence of static loading and descending seepage of concentrated alkaline solution on deformation appearances in the soil foundation and forming the construction tilt using the example of an overhead crane. Methodology. The methodology of research included laboratory determination of the physico-mechanical and subsidence properties of soils focusing on alluvial-diluvial loam and groundwater chemical composition at the studied site, evaluation of leaching parameters of loam soil phase by an alkaline solution using the X-ray fluorescent spectrometer СЕР-01 ElvaX Plus, and variable-based calculations of soil subsidence based on the standard techniques applied in geotechnics taking into account partial dissolution of soil solid phase. Findings. This study examined the case of an overhead crane with the foundation affected by the leakages of strong alkaline solutions from technological basins on the ground. Laboratory studies have established the components of Al2O3, Fe2O3, CaO, K2O soluble with strong alkaline solution and their share of 13,3% in the solid phase of the alluvial-diluvial loam sampled at the site. These compounds can transform into more soluble salts in a concentrated alkaline medium, which creates the conditions for the development of soil collapse and subsidence, with the chemically induced deformations being more significant in comparison to those in soils filled with a neutral pore solution. Calculations of soil subsidence and collapse with and without taking into account the chemical impact on soils under the overhead crane foundation showed that the non-uniform critical deformations of 5...10 cm leading to an unacceptable tilt between the crane columns of 0.004 can be caused only by the long-term descending seepage of an alkaline solution and leaching the alluvial-diluvial loam. The calculated deformations and tilt correlate with the appeared deformations and the tilt between the crane columns that exceeded the maximum allowed value since 2016, which affected the operating conditions for this construction. Reducing the bearing capacity of soils due to the influence of alkaline solution occurred after engineering reclamation of soils performed prior to crane operation more than two decades ago. Scientific novelty. The effect of strong alkaline solution that seeps through the upper soil layer loaded by constructions has been evaluated; the share of dissolved solid phase in the affected soil is estimated at 1-1,5%, which is in agreement with the dissolution parameters of soil influenced by strong alkaline solutions evaluated in this study and other researchers. Practical value. The results obtained can be applied for long-term predicting the operational conditions and stability of buildings constructed on soils subjected to seepage of chemically aggressive solutions.

scholarly journals Investigation of the thermal state of the elements of a technological electron beam gun under long–term operating conditions

2021 ◽  
Vol 2077 (1) ◽  
pp. 012008
Author(s):  
I A Kharitonov ◽  
A L Goncharov ◽  
E K Titarev ◽  
A V Nekhoroshev
Keyword(s):  
Thermal State ◽  
Critical Value ◽  
Operating Conditions ◽  
Electron Gun ◽  
Short Term ◽  
Operating Modes ◽  
Cathode Assembly ◽  
Forced Cooling ◽  
The Mathematical Model

Abstract The paper presents the results of a study of the thermal state of the elements of the cathode assembly of the ELA–15 welding electron gun. It was revealed that in short–term operating modes of the gun (up to 60 minutes) at any energy parameters of heating the hexaboride cathode, it is possible not to use forced cooling of the cathode assembly. The case temperature in such modes did not exceed 30°C. The increase in the temperature of the gun body occurred 15 minutes after the start of heating the cathode. In long–term operating modes with forced cooling of the gun, the temperature of the gun body increased by 2 – 3°C and remained stable throughout the operation. When the cooling was turned off, the temperature of the gun body reached a critical value in 60 minutes. The section of natural cooling of the cathode obtained in the work, which appears when the heating of the cathode is stopped, is well approximated by a power function. It is convenient to use this dependence to verify the mathematical model of the thermal state of the electron gun.

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