The Effect of Baffle Installation on the Performance of a Single-Cell Stabilization Pond

1993 ◽  
Vol 27 (7-8) ◽  
pp. 45-52 ◽  
Author(s):  
R. Pedahzur ◽  
A. M. Nasser ◽  
I. Dor ◽  
B. Fattal ◽  
H. I. Shuval
Keyword(s):  
Retention Time ◽  
Thermal Stratification ◽  
Optical Observations ◽  
Tracer Study ◽  
Treatment Efficiency ◽  
Long Tail ◽  
Stabilization Pond ◽  
Indicator Microorganism ◽  
Influent Flow

The effect of baffles on the performance of an ineffective, single-celled stabilization pond with theoretical retention time of 5-10 days, was investigated. The efficiency of the pond was evaluated by comparing the microbiological and chemical quality of pond's influent and effluent, as well as by hydraulic tests. Removal of indicator microorganism (1 log) and BOD5 (55%) remained unchanged, regardless of the number of baffles. Tracer study findings were characterized by the appearance of a peak of tracer within 15-20 hours after injection of the tracer, followed by a long “tail” of lower concentration. These findings, along with optical observations, indicated that the baffles succeeded in channeling influent flow to the planned routes (resulting in increased traveling distance of the wastewater). However, the actual retention time of the influent, particularly a small but important fraction of it, remained short regardless of baffle installation. The lack of mixing caused by thermal stratification of the water column resulted in rapid bottom flow in the cool hypolimnion. These findings may explain, in part, the lack of success in improving treatment efficiency.

scholarly journals The Influence of Different Plasma Cell Discharges on the Performance Quality of Surgical Gown Samples

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4329
Author(s):  
Atif H. Asghar ◽  
Ahmed Rida Galaly
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Exposure Time ◽  
Electrical Characteristics ◽  
Cathode Fall ◽  
Treatment Efficiency ◽  
Performance Quality ◽  
Surgical Gown ◽  
The One

An experimental study was performed on a low-density plasma discharge using two different configurations of the plasma cell cathode, namely, the one mesh system electrodes (OMSE) and the one mesh and three system electrodes (OMTSE), to determine the electrical characteristics of the plasma such as current–voltage characteristics, breakdown voltage (VB), Paschen curves, current density (J), cathode fall thickness (dc), and electron density of the treated sample. The influence of the electrical characteristics of the plasma fluid in the cathode fall region for different cathode configuration cells (OMSE and OMTSE) on the performance quality of a surgical gown was studied to determine surface modification, treatment efficiency, exposure time, wettability property, and mechanical properties. Over a very short exposure time, the treatment efficiency for the surgical gown surface of plasma over the mesh cathode at a distance equivalent to the cathode fall distance dc values of the OMTSE and for OMSE reached a maximum. The wettability property decreased from 90 to 40% for OMTSE over a 180 s exposure time and decreased from 90 to 10% for OMSE over a 160 s exposure time. The mechanisms of each stage of surgical gown treatment by plasma are described. In this study, the mechanical properties of the untreated and treated surgical gown samples such as the tensile strength and elongation percentage, ultimate tensile strength, yield strength, strain hardening, resilience, toughness, and fracture (breaking) point were studied. Plasma had a more positive effect on the mechanical properties of the OMSE reactor than those of the OMTSE reactor.

Algicidal and Bactericidal Effect of Potassium Monopersulfate Compound on Eutrophic Water

2014 ◽  
Vol 707 ◽  
pp. 259-262 ◽  
Author(s):  
Ming Song Wu ◽  
Xin Yang Xu ◽  
Xun Xu ◽  
Yue Ting Zeng ◽  
Jing Nan Zhang ◽  
...  
Keyword(s):  
Contact Time ◽  
Influence Factors ◽  
Bactericidal Effect ◽  
Major Influence ◽  
Treatment Efficiency ◽  
Compound A ◽  
Eutrophic Water ◽  
Landscape Water ◽  
Algae And Bacteria

Algae and bacteria blooms in eutrophication in summer have made the quality of landscape water degradation. Treatment efficiency of potassium monopersulfate compound, a new kind of oxidation reagent, on killing algae and bacteria has been valued and the effect of influence factors, such as dosage, contact time and temperature are also discussed. The results indicated that potassium monopersulfate is appropriate for killing algae and bacteria in landscape water, dosage and contact time are the major influence factors. The contact time should be longer than 20min and the algicidal rate is higher when the temperature is above 20°C.

COD removal of phenolic wastewater by biological activated carbon-sequencing batch reactor in the presence of 2,4-DCP

2000 ◽  
Vol 42 (5-6) ◽  
pp. 171-178 ◽  
Author(s):  
S.-R. Ha ◽  
L. Qishan ◽  
S. Vinitnantharat
Keyword(s):  
Activated Carbon ◽  
Retention Time ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Cod Removal ◽  
High Loading ◽  
Treatment Efficiency ◽  
Biological Activated Carbon ◽  
Treatment Performance ◽  
Phenolic Wastewater

Treatment performance of COD in the presence of 2,4-dichlorophenol (2,4-DCP) was explored by using a biological activated carbon-sequencing batch reactor (BAC-SBR) system. Two COD levels of basic substrate were synthesized with a mixture of phenol and 2,4-dichlorophenol. Although effluent concentration was increased with reduction of sludge retention time (SRT) from 8-days to 3-days, treatment efficiency was indicated more than 90% of COD in all SRTs applied. Reactors operated with acclimated sludge could be expected to cope with quite high loading of inhibitory substances.

Development of an integrated membrane process for water reclamation

2005 ◽  
Vol 51 (6-7) ◽  
pp. 455-463 ◽  
Author(s):  
C.H. Lew ◽  
J.Y. Hu ◽  
L.F. Song ◽  
L.Y. Lee ◽  
S.L. Ong ◽  
...  
Keyword(s):  
Retention Time ◽  
Unique Feature ◽  
Inhibitory Effect ◽  
Water Reclamation ◽  
The Novel ◽  
Membrane Process ◽  
Treatment Efficiency ◽  
Effluent Quality ◽  
Toc Removal ◽  
Ro Concentrate

An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.94% and it consistently produced product water usable for high value reuse applications.

scholarly journals Setting Standards to Promote Artificial Intelligence in Colon Mass Endoscopic Sampling

2019 ◽  
Author(s):  
Yueping Zheng ◽  
Ruizhang Su ◽  
Wangyue Wang ◽  
Sijun Meng ◽  
Hang Xiao ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Light Source ◽  
Recognition Accuracy ◽  
Poor Quality ◽  
Digestive Endoscopy ◽  
Treatment Efficiency ◽  
Picture Processing ◽  
Medical Institutions ◽  
Multiple Regions

ABSTRACTObjectiveArtificial intelligence (AI) has undeniable values in detection, characterization, and monitoring of tumors during cancer imaging. However, major AI explorations in digestive endoscopy have not been systematically planned, and more important, most AI productions are based on Single-center Studies (ScSs). ScSs result in data scarcity, redundancy as well as island effects, which leads to some limitations in applying it on endoscopy. We investigate the disadvantages of picture processing which may effect the AI detection, and make improvements in AI detection and image recognition accuracy.DesignCurrent investigation aggregates a total of 2,500 gastroenteroscopy samples from various hospitals in multiple regions and carries out deep learning.ResultsIt is found that factors inconducive to AI recognition are common such as: (a) the gastrointestinal tract is not cleaned up completely; (b) shooting angle (from left to right and the top of polyp are unexposed clearly), shooting distance (too close or too far to shoot causes the lump to be unclear), shooting light (insufficient light source or overexposed light source in mass) and unstable shooting lead to poor quality of pictures.ConclusionWe set standards for a multicenter cooperation involving three-level medical institutions from the provincial, municipal and county to improve the recognition accuracy as well as the diagnosis and treatment efficiency meanwhile.

Purification by a natural waste stabilization pond: influence of weather and ageing on treatment quality and sediment thickness

1995 ◽  
Vol 31 (12) ◽  
pp. 191-200 ◽  
Author(s):  
S. Schetrite ◽  
Y. Racault
Keyword(s):  
Treatment Quality ◽  
Sediment Thickness ◽  
Nitrogen And Phosphorus ◽  
Climate Conditions ◽  
Stabilization Pond ◽  
Waste Stabilization Pond ◽  
The North ◽  
Treated Effluent ◽  
Waste Stabilization

The natural waste stabilization pond of Vauciennes, located in the north of France, underwent regular monitoring from October 1981 to July 1991, within the framework of a programme studying the evolution of operation parameters related to the ageing of plants. This study enabled us to assess the variations in the quality of the discharge depending on the season, in particular concerning the nitrogen and phosphorus parameters. The input/output reports made it possible to make specifications concerning the variations of the loads to be treated and the overloads caused by rainy episodes, and the real performances of the plants in relation to rainfall, evaporation, hydraulic exchanges with the soil and interannual seasonal variations. The evolution of the treatment, characterised by the parameters of the treated effluent, was observed, on the basis of equivalent climate conditions. Lastly, the growth of the deposits and their location in the first pond observed based on the systematic establishment of a cartography of the bottom of the pond.

scholarly journals Comet and Asteroid Ephemerides for Spacecraft Encounters

1997 ◽  
Vol 165 ◽  
pp. 1-12
Author(s):  
Donald K. Yeomans
Keyword(s):  
Body Position ◽  
Significant Degree ◽  
The Body ◽  
Optical Observations ◽  
Data Set ◽  
Angle Data ◽  
Orbital Periods ◽  
The Times ◽  
Astrometric Data

AbstractTo a significant degree, the success of spacecraft missions to comets and asteroids depends upon the accuracy of the target body ephemerides. In turn, accurate ephemerides depend upon the quality of the astrometric data set used in determining the object’s orbit and the accuracy with which the target body’s motion can be modelled. Using error analyses studies of the target bodies for the NEAR, Muses-C, Clementine 2, Stardust, and Rosetta missions, conclusions are drawn as to how to minimize target body position uncertainties at the times of encounter. In general, these uncertainties will be minimized when the object has a good number of optical observations spread over several orbital periods. If a target body lacks a lengthy data interval, its ephemeris uncertainties can be dramatically reduced with the use of radar Doppler and delay data taken when the body is relatively close to the Earth. The combination of radar and optical angle data taken at close Earth distances just before a spacecraft encounter can result in surprisingly small target body ephemeris uncertainties.

Taenia eggs in a stabilization pond system with poor hydraulics: concern for human cysticercosis?

2013 ◽  
Vol 68 (12) ◽  
pp. 2698-2703 ◽  
Author(s):  
Matthew E. Verbyla ◽  
Stewart M. Oakley ◽  
Louis A. Lizima ◽  
Jie Zhang ◽  
Mercedes Iriarte ◽  
...  
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Taenia Solium ◽  
Treated Wastewater ◽  
Human Consumption ◽  
Dynamics Modeling ◽  
Hydraulic Residence Time ◽  
Stabilization Pond ◽  
Pond System ◽  
In Series

The objective of this study is to compare the removal of Taenia eggs to the removal of Ascaris eggs in a wastewater stabilization pond system consisting of three ponds in series, where the hydraulic residence time distribution has been characterized via a tracer study supported by computational fluid dynamics modeling. Despite a theoretical hydraulic retention time of 30 days, the peak dye concentration was measured in the effluent of the first pond after only 26 hours. The smaller-sized Taenia eggs were detected in higher concentrations than Ascaris eggs in the raw wastewater. Ascaris eggs were not detected in the pond system effluent, but 45 Taenia eggs/L were detected in the system effluent. If some of these eggs were of the species Taenia solium, and if the treated wastewater were used for the irrigation of crops for human consumption, farmers and consumers could potentially be at risk for neurocysticercosis. Thus, limits for Taenia eggs in irrigation water should be established, and precautions should be taken in regions where pig taeniasis is endemic. The results of this study indicate that the theoretical hydraulic retention time (volume/flow) of a pond is not always a good surrogate for helminth egg removal.

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