scholarly journals Impact of surface maintenance on BioSand filter performance and flow

2017 ◽  
Vol 15 (2) ◽  
pp. 262-272 ◽  
Author(s):  
Sarah Singer ◽  
Brain Skinner ◽  
Raymond E. Cantwell
Keyword(s):  
Flow Rate ◽  
Recovery Period ◽  
Pause Time ◽  
Effluent Water ◽  
Removal Rates ◽  
Filter Performance ◽  
Biosand Filter ◽  
Slow Sand Filter ◽  
And Performance ◽  
Sr Method

The BioSand filter (BSF) is a household scaled, intermittently operated, slow sand filter. The BSF requires maintenance to remove trapped sediments. This study evaluated the effects of maintenance on the filter's flow rate and performance. Four concrete BSFs received three styles of maintenance: surface agitation (SA), stirring method (SM), and sand removal (SR). Effluent water was collected from the filter between 0–2 L effluent (0–2 L effluent) and between 15–20 L effluent (15 L+ effluent). After maintenance, effluent at 15 L+ (no pause time) showed a significant decrease in thermotolerant coliform removal rates by 0.66–0.91 log (SA), 0.57–0.67 log (SM) and 0.32–0.83 log (RM) (<0.001). Effluent water at 0–2 L (with pause time) did not significantly decrease in thermotolerant coliform removal rates (>0.17) for any maintenance method. The recovery duration after maintenance for all methods at 0–2 L effluent had a median recovery of <1.2 days. The effluent at 15 L+ had a longer recovery period (at least 3.9, 3.0 and 12.75 days for the SA, SM, and SR method, respectively). The flow rate recovery for SA (76%) and SM (82%) was lower compared to SR (138%).

Field Evaluation of Long-Term Performance and Use of Biosand Filters in Posoltega, Nicaragua

2009 ◽  
Vol 44 (2) ◽  
pp. 111-121 ◽  
Author(s):  
Jason C. Vanderzwaag ◽  
James W. Atwater ◽  
Karen H. Bartlett ◽  
Derek Baker
Keyword(s):  
Loading Rate ◽  
Field Evaluation ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
User Training ◽  
Filter Performance ◽  
Biosand Filter ◽  
Biosand Filters ◽  
And Performance

Abstract An evaluation was conducted in 2007 on biosand filters that were installed in Posoltega, Nicaragua in 1999 and 2004.The objectives were to characterize the condition and use of filters eight and three years after installation, determine filter performance of those filters still in use, and identify determinants of successful long-term use and performance. Methods consisted of household identification, user questionnaires, and water quality testing. Of the 234 filters installed, only 24 were found to still be in use. Average log reductions were 1.73 (98%) for total coliforms, 1.36 (96%) for Escherichia Coli, and 0.91 (88%) for turbidity. Statistically significant effects were detected for the magnitude of the contamination of source water, the peak hydraulic loading rate, and the standing depth of water over the filter media. Questionnaire results indicated user training on filter maintenance could improve the peak hydraulic loading rate and hence filter performance. The low rate of sustained use (10%) is an indication of failed implementation, and is attributable to structural failure, particularly cracking of the concrete filters from 2004. Nonetheless, this evaluation demonstrated the biosand filter technology to be robust since those filters still in use were performing as expected three and eight years postimplementation.

scholarly journals Impact of rock alum pretreatment on biosand filter performance in Cambodia

2020 ◽  
Vol 10 (1) ◽  
pp. 166-170 ◽  
Author(s):  
Kevin D. Curry ◽  
Christopher P. Bloch ◽  
Vantha Hem
Keyword(s):  
River Water ◽  
Flow Rate ◽  
Water Source ◽  
Drinking Water Source ◽  
Source Water ◽  
Filter Performance ◽  
Biosand Filter ◽  
Tonle Sap ◽  
Alum Treatment ◽  
Water Filters

Abstract Alum is often recommended by WASH agencies as a pretreatment flocculent to improve filtration in biosand filters (BSFs) for communities using a turbid drinking water source. Floating villages on the Tonle Sap Lake in Cambodia using BSFs encounter severe declines in filtration rates while using alum, resulting in reduced use of the BSF. We tested the effect of rock alum treatment on flow rate and turbidity. The flow rate of all BSFs declined over time, but degradation of flow was more rapid for alum-treated water than untreated water. Rock alum treatments significantly reduced the turbidity of borrow pit source water. Filters switched to untreated river water decreased in turbidity to levels ≤ rock alum-treated river water. Rock alum treatments increased aluminum in source water 4–15 times, but filtration by BSFs decreased levels of aluminum to near 0.05 mg/L. Though rock alum effectively reduces turbidity in source water, we believe it continues its coagulation inside the BSF during pause periods, negatively impacting flow rates.

Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE

1989 ◽  
Vol 47 ◽  
pp. 1000-1001
Author(s):  
Joe A. Mascorro ◽  
Gerald S. Kirby
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Succinic Anhydride ◽  
Volume Flow Rate ◽  
Mass Density ◽  
Uranyl Acetate ◽  
Volume Flow ◽  
Base Resin ◽  
And Performance ◽  
Acid Anhydrides

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.

Analysis of organic removal rates in the aerated submerged fixed film process

1998 ◽  
Vol 38 (8-9) ◽  
pp. 213-221 ◽  
Author(s):  
Mohamed F. Hamoda ◽  
Ibrahim A. Al-Ghusain
Keyword(s):  
Pilot Plant ◽  
Removal Rate ◽  
Domestic Wastewater ◽  
Removal Rates ◽  
Hydraulic Loading ◽  
Organic Removal ◽  
Wide Range ◽  
Fixed Film ◽  
Cod Removal Rate ◽  
And Performance

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Influence of Particle and Grain Size on Sand Filtration: Effect on Head Loss and Turbidity

2020 ◽  
Vol 8 (2) ◽  
pp. 36
Author(s):  
Racha Medjda Bouchenak Khelladi ◽  
Abdelghani Chiboub Fellah ◽  
Maxime Pontié ◽  
Fatima Zohra Guellil
Keyword(s):  
Particle Size ◽  
Flow Rate ◽  
Granular Media ◽  
Particle Concentration ◽  
Head Loss ◽  
Sand Filtration ◽  
Circular Column ◽  
Filter Performance ◽  
Filter Operation ◽  
Suspended Matters

Sand filtration is an eco-friendly method to treat either drinking water or wastewater ; it requires only natural granular media. It is also easy to use and to maintain ; the only problem they face is clogging that affects filter performance, that can be detected when head loss or turbidity increase. The purpose of this work is to see what are the factors that influence the performance of filter operation, for this, we used a pilot consisting on a circular column filled with sand (from South Algeria), where various parameters were tested; pressure, flow rate, sand granulometry, suspended matters and particle concentration of the water which is filtered. After eighteen weeks of operation, we have found that head loss increases by decreasing granulometry and increasing flow rate, pressure, particle size, and concentration. However, turbidity increases by decreasing particle size and increasing granulometry and particle concentration. Turbidity and head loss have different behaviour towards the same parameter; that is why it is necessary to take them into account in order to find a compromise between acceptable head loss / turbidity for a good functioning of the filter.

scholarly journals Fiberglass Vs. Synthetic Air Filtration Media

2002 ◽  
Vol os-11 (3) ◽  
pp. 1558925002OS-01 ◽  
Author(s):  
Edward Vaughn ◽  
Gayetri Ramachandran
Keyword(s):  
Research Work ◽  
Test Methods ◽  
Air Filtration ◽  
Filter Media ◽  
Air Filter ◽  
Filter Performance ◽  
And Performance ◽  
Synthetic Media

This paper deals with ASHRAE filters used in air filtration applications and summarizes, on the basis of current research work, some of the reasons for the disagreement that exists among filter manufacturers concerning the properties and performance of various types of air filter media in general, glass and synthetic media in particular. Attention is also drawn to some important items that need to be incorporated in test methods and to some factors that could be affecting filter performance

Performance and Development of a Miniature Rotary Shaft Pump

2005 ◽  
Vol 127 (4) ◽  
pp. 752-760 ◽  
Author(s):  
Danny Blanchard ◽  
Phil Ligrani ◽  
Bruce Gale
Keyword(s):  
Flow Rate ◽  
Pressure Rise ◽  
Electronics Cooling ◽  
Maximum Flow ◽  
Operating Conditions ◽  
Working Fluid ◽  
Hydraulic Efficiency ◽  
Potential Applications ◽  
Total Analysis ◽  
And Performance

The development and performance of a novel miniature pump called the rotary shaft pump (RSP) is described. The impeller is made by boring a 1.168 mm hole in one end of a 2.38 mm dia shaft and cutting slots in the side of the shaft at the bottom of the bored hole such that the metal between the slots defines the impeller blades. The impeller blades and slots are 0.38 mm tall. Several impeller designs are tested over a range of operating conditions. Pump performance characteristics, including pressure rise, hydraulic efficiency, slip factor, and flow rate, are presented for several different pump configurations, with maximum flow rate and pressure rise of 64.9ml∕min and 2.1 kPa, respectively, when the working fluid is water. Potential applications include transport of biomedical fluids, drug delivery, total analysis systems, and electronics cooling.

Effects of Water Injection on the Power Boost of a Twin Turbocharged Vehicle

2014 ◽  
Author(s):  
McDonald A. Fawcett ◽  
Jobaidur R. Khan
Keyword(s):  
Flow Rate ◽  
Power Output ◽  
Water Injection ◽  
Time Data ◽  
Mixture Flow ◽  
Fuel Flow ◽  
Methanol Mixture ◽  
Power Enhancement ◽  
And Performance ◽  
Vehicle Sensors

The injection of a water/methanol mixture into the intake airflow of turbocharged street racing vehicles has long been known to increase the power and performance, though actual data proves difficult to obtain. In an attempt to maximize the power output of a twin-turbocharged Porsche engine, a water/methanol mixture is introduced into the intake airflow. The injection decreased the temperature and increased the density of the intake air while increasing the compression ratio of the cylinder beyond the effects of the turbocharger itself. The real-time data was used to do the analysis. In an attempt to maximize the power enhancement, the injection parameters are modified. The vehicle sensors were used to obtain temperatures of the intake air, exhaust air, and the engine coolant. The fuel flow rate, air flow rate, mixture flow rate, and manifold pressure in conjunction with temperature measurements was used to determine the mass flow rate of the system. The properties of the mixture components were used to determine the work created by the system, which in turn leads to the power output of the system. Determining the power enhancement created by the water/methanol injection, and potentially maximizing its effect is the focus of this work.

Calculation Model Based Design-Point Gas Generator Performance Adaptation Method

2017 ◽  
Author(s):  
Shiyao Li ◽  
Zhenlin Li ◽  
Ning Huang
Keyword(s):  
Simulation Model ◽  
Flow Rate ◽  
Calculation Model ◽  
Adaptation Process ◽  
Performance Parameters ◽  
Gas Generator ◽  
Performance Simulation ◽  
And Performance ◽  
Performance Adaptation ◽  
Adaptation Method

Accurate performance simulation can provide operating parameters and performance parameters for the gas turbine’s optimization, maintenance, and fault diagnosis. However, the components maps necessary for performance simulation are not publically available. In addition, the same type of gas turbine has slightly different component operating characteristics due to components′ variations in status and assembly tolerance. These causes bring real difficulties to the research of performance simulation. In order to obtain accurate components characteristics and performance simulation results, the original or generic components maps should be modified by the scaling factors. In the process of calculating scaling factors, the simulation model is applied repeatedly to determine the engine’s actual performance parameters until the simulated gas path thermal parameters are compatible with the actual measureable data. This paper introduces a new adaptation method and substitutes the calculation model with the simulation model in the adaptation process. It directly calculates the mass flow rate, isentropic efficiency, and pressure ratio of compressor and turbine based on measureable parameters such as gas path temperature, pressure, fuel component and mass flow rate. Moreover, this paper introduces the virtual gas generator model that enhances the applicability of calculation model based performance adaptation method on gas generators with different structures. This method has been applied to GE PGT25+ gas generator (single-spool) and RR RB211-24G gas generator (double-spool). Compared with the simulation model used in adaptation process, performance calculation model is much simpler and less time consuming.

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