Bacterial adaptation and performance of household biosand water filters in differing temperatures

2015 ◽  
Vol 16 (3) ◽  
pp. 794-801 ◽  
Author(s):  
N. Arnold ◽  
A. Archer ◽  
B. Barkdoll
Keyword(s):  
Ambient Temperature ◽  
Total Coliform ◽  
Performance Difference ◽  
Biosand Filter ◽  
Point Of Use ◽  
Significant Performance ◽  
Freezing Temperatures ◽  
And Performance ◽  
Water Filters ◽  
Microbial Removal

The household biosand filter (BSF) is a highly utilized point-of-use water treatment tool. The effect of ambient temperature on the ability of the BSF to remove microbes from water is unclear. Model filters were distributed among different temperature-controlled laboratories and dosed daily with surface water amended with sewage. Comparison of the total coliform and Escherichia coli counts in the influent versus effluent revealed an immediate drop in the removal efficiencies of filters held in colder rooms. This performance difference, however, became less pronounced over the course of the experiment until no significant performance difference was detected between filters regardless of their ambient temperature, perhaps due to microbial adaptation within the BSFs. Subsequently, two-thirds of the filters were exposed to freezing temperatures, thawed, and re-tested for microbial removal. All filters exposed to freezing temperatures showed significant drops in microbial removal compared to control filters. Filters exposed to the most extreme temperatures showed the greatest drop in performance.

scholarly journals Biosand Filter as a Point-of-Use Water Treatment Technology: Influence of Turbidity on Microorganism Removal Efficiency

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2302
Author(s):  
Daniela A. Duran Romero ◽  
Maria Cristina de Almeida Silva ◽  
Beni J. M. Chaúque ◽  
Antônio D. Benetti
Keyword(s):  
Water Treatment ◽  
High Efficiency ◽  
Total Coliform ◽  
Water Safety ◽  
Treatment Technology ◽  
Water Turbidity ◽  
Biosand Filter ◽  
Point Of Use ◽  
Pure Cultures ◽  
Microorganism Removal

The number of people living without access to clean water can be reduced by the implementation of point-of-use (POU) water treatment. Among POU treatment systems, the domestic biosand filter (BSF) stands out as a viable technology. However, the performance of the BSF varies with the inflow water quality characteristics, especially turbidity. In some locations, people have no choice but to treat raw water that has turbidity above recommended levels for the technology. This study aimed to measure the efficiency with which the BSF removes microorganisms from well water and from fecal-contaminated water with turbidity levels of 3, 25, and 50 NTU. Turbidity was controlled by the addition of kaolin to water. Turbidity removal varied from 88% to 99%. Reductions in total coliform (TC) and Escherichia coli ranged from 0.54–2.01 and 1.2–2.2 log removal values (LRV), respectively. The BSF that received water with a higher level of turbidity showed the greatest reduction in the concentration of microorganisms. Additional testing with water contaminated with four bacterial pure cultures showed reductions between 2.7 and 3.6 LRV. A higher reduction in microorganisms was achieved after 30–35 days in operation. Despite the filter’s high efficiency, the filtrates still had some microorganisms, and a disinfection POU treatment could be added to increase water safety.

scholarly journals Field Investigation and Economic Benefit of a Novel Method of Silver Application to Ceramic Water Filters for Point-Of-Use Water Treatment in Low-Income Settings

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 285
Author(s):  
Nkosinobubelo Ndebele ◽  
Joshua N. Edokpayi ◽  
John O. Odiyo ◽  
James A. Smith
Keyword(s):  
Silver Nanoparticles ◽  
Water Treatment ◽  
Silver Nitrate ◽  
Silver Nanoparticle ◽  
Total Coliform ◽  
Raw Material ◽  
E Coli ◽  
Ceramic Water Filters ◽  
Point Of Use ◽  
Water Filters

In this study, we report on field testing of ceramic water filters (CWFs) fabricated using a new method of silver application (using silver nitrate as a raw material) compared to conventionally manufactured CWFs (fabricated with silver nanoparticles). Both types of filters were manufactured at the PureMadi ceramic filter production facility in Dertig, South Africa. Thirty households received filters fabricated with silver nitrate (AgNO3), and ten of those households were given an extra filter fabricated with silver nanoparticles. Filter performance was quantified by measurement of total coliform and Escherichia coli (E. coli) removal and silver residual concentration in the effluent. Silver-nitrate CWFs had removal efficiencies for total coliforms and E. coli of 95% and 99%, respectively. A comparison of the performance of silver-nitrate and silver-nanoparticle filters showed that the different filters had similar levels of total coliform and E. coli removal, although the silver nitrate filters produced the highest average removal of 97% while silver nanoparticles filters recorded an average removal of 85%. Average effluent silver levels were below 10 ppb for the silver-nitrate and silver-nanoparticle filters, which was significantly below the Environmental Protection Agencies of the United States (EPA) and World Health Organization (WHO) secondary guidelines of 100 ppb. Silver-nitrate filters resulted in the lowest effluent silver concentrations, which could potentially increase the effective life span of the filter. A cost analysis shows that it is more economical to produce CWFs using silver nitrate due to a reduction in raw-material costs and reduced labor costs for production. Furthermore, the production of silver-nitrate filters reduces inhalation exposure of silver by workers. The results obtained from this study will be applied to improve the ceramic filtration technology as a point-of-use (POU) water treatment device and hence reduce health problems associated with microbial contamination of water stored at the household level.

The impact of loading frequency and copper as a biocide on biosand filter performance

2013 ◽  
Vol 3 (3) ◽  
pp. 355-364 ◽  
Author(s):  
Elizabeth M. Hyde ◽  
Laura W. Lackey
Keyword(s):  
Loading Frequency ◽  
Sand Filters ◽  
Performance Effect ◽  
Filter Performance ◽  
Copper Addition ◽  
Biosand Filter ◽  
Point Of Use ◽  
Significant Difference ◽  
Significant Performance ◽  
The Impact

Biological sand filters (BSFs) can appropriately serve as point-of-use water treatment in developing nations. This study examined the benefit of adding copper to a BSF, and evaluated the impact of its addition in relation to extended pause times. Four 70-L BSFs were created – copper was incorporated in the packing of the two BSFs labeled Filter 1 and Filter 3. Filters 1 and 2 were loaded daily while Filters 3 and 4 were watered every third day. Source water was taken from the Ocmulgee River in Macon, Georgia. To investigate variation due to watering frequency and biocidal addition, BSF performance was quantified using coliforms, turbidity, solids, dissolved oxygen, pH, and copper analyses. E. coli removal efficiencies for Filters 1, 2, 3, and 4 averaged 90, 77, 87, and 80%, respectively. Paired t-tests at α = 0.05 indicate that effluent coliform concentrations from filters watered daily were significantly impacted by the presence of copper. Filters loaded every third day showed no significant performance effect from copper addition on coliform removal efficiency. Similar paired t-tests at α = 0.05 for turbidity, solids, and COD showed no significant difference between filter performance.

scholarly journals Under-Sink Activated Carbon Water Filters Effectively Remove Lead from Private Well Water for over Six Months

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3584
Author(s):  
Riley Mulhern ◽  
Jacqueline MacDonald Gibson
Keyword(s):  
Activated Carbon ◽  
Blood Lead ◽  
The United States ◽  
Well Water ◽  
Point Of Use ◽  
Metals Removal ◽  
Lead Levels ◽  
Minimal Data ◽  
Water Filters ◽  
Private Wells

Children who rely on private well water in the United States have been shown to be at greater risk of having elevated blood lead levels. Evidence-based solutions are needed to prevent drinking water lead exposure among private well users, but minimal data are available regarding the real-world effectiveness of available interventions like point-of-use water treatment for well water. In this study, under-sink activated carbon block water filters were tested for lead and other heavy metals removal in an eight-month longitudinal study in 17 homes relying on private wells. The device removed 98% of all influent lead for the entirety of the study, with all effluent lead levels less than 1 µg/L. Profile sampling in a subset of homes showed that the faucet fixture is a significant source of lead leaching where well water is corrosive. Flushing alone was not capable of reducing first-draw lead to levels below 1 µg/L, but the under-sink filter was found to increase the safety and effectiveness of faucet flushing. The results of this study can be used by individual well users and policymakers alike to improve decision-making around the use of under-sink point-of-use devices to prevent disproportionate lead exposures among private well users.

Fuzzy System for DOA Estimation of Coherent Signals

2013 ◽  
Vol 427-429 ◽  
pp. 575-581
Author(s):  
Ya Ling Chen ◽  
Chien Chou Lin
Keyword(s):  
Fuzzy System ◽  
High Performance ◽  
Expert Knowledge ◽  
Doa Estimation ◽  
Coherent Signals ◽  
Fuzzy Logic Systems ◽  
Significant Performance ◽  
And Performance ◽  
Low Sensitivity ◽  
Resolution Estimation

This paper presents an efficient direction-of-arrival (DOA) Estimator for dealing with coherent signals. The empirical results show that significant performance degradation occurs when coherent signals coexist. Therefore, an utilizes the low sensitivity of Bartlett algorithm in estimation of DOAs for coherent signals to yield a low-resolution estimation of DOAs as initial search angle and uses fuzzy logic systems with incorporating expert knowledge to improve the resolution and performance of estimation of DOAs in coherent signals environment. Finally, numerical example was analyzed to illustrate high performance of the proposed method and to confirm the designed procedure.

Virus removal efficiency of ceramic water filters: effects of bentonite turbidity

2013 ◽  
Vol 14 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Cameron Farrow ◽  
Edward McBean ◽  
Hamidreza Salsali
Keyword(s):  
Removal Efficiency ◽  
Potable Water ◽  
Source Water ◽  
Virus Removal ◽  
Ceramic Water Filters ◽  
Point Of Use ◽  
Cake Layer ◽  
Human Enteric Viruses ◽  
Removal Efficiencies ◽  
Water Filters

Ceramic water filters (CWFs) are utilized in many developing countries as point-of-use (POU) water treatment devices, to reduce waterborne pathogens in potable water. Virus removal efficiencies of several CWFs are investigated under various influent conditions using MS2 (ATCC: 15597-B1) as a surrogate phage for human enteric viruses. The addition of bentonite turbidity (6–8 NTU) in the influent source water showed increased viral removal efficiency of CWFs by 0.1–0.2 log compared to tests involving clear (<1 NTU) influents. Trials employing an applied clay cake layer, formed using highly turbid influent source water (100 NTU) and no cleaning regime between trials, resulted in viral removal efficiency values of 1.5–2.5 log, compared to 0.2–0.5 log during non-obstructed trials.

scholarly journals Use of ceramic pot filter (CPF) technology under pressure in an in-line pumping system

2017 ◽  
Vol 18 (3) ◽  
pp. 843-852
Author(s):  
Travis D. Gardner ◽  
Joe D. Guggenberger
Keyword(s):  
Water Treatment ◽  
Low Cost ◽  
Total Coliform ◽  
Fecal Coliforms ◽  
Coliform Bacteria ◽  
Limiting Factor ◽  
Water Production ◽  
Pumping System ◽  
Point Of Use ◽  
Logarithmic Reduction

Abstract Ceramic pot filters (CPFs) are an effective point of use water treatment device in developing nations due to their low cost and effectiveness. CPFs are gravity fed, typically making water production a major limiting factor to a CPF's lifetime and acceptability. Directly connecting CPFs to in-line pumping systems or systems with an elevated storage tank would allow filter usage for constant water treatment at increased pressures, increasing the quantity of treated water. Ceramic disks were manufactured for testing in a specially designed housing apparatus. Filters of varying thicknesses and clay to sawdust mass ratios were manufactured to fit tightly. Flowrate and microbiological removal efficacy (logarithmic reduction value (LRV)) were determined over the testing period at various pressures. Flowrate values ranged from 2.44 to 9.04 L per hour, significantly higher than traditional CPF technology. LRVs ranged from 1.1 to 2.0, lower than traditional CPF technology but still effective at removing most Escherichia coli and total coliform bacteria. Filters proved effective at removing total and fecal coliforms at pressures less than 70 kilopascals. The optimum filter had a thickness of 3.2 cm and clay to sawdust ratio of 6:1 by mass. Filters proved to be ineffective if flowrates were above 5 L/h.

scholarly journals Production Quality Improvements and Energy Cost Reductions Associated With Compressed Air

2006 ◽  
Author(s):  
Mark Krisa ◽  
David Voelker
Keyword(s):  
Production Quality ◽  
Production Equipment ◽  
Compressed Air ◽  
Quality Improvements ◽  
Citrus Industry ◽  
Point Of Use ◽  
Discharge Location ◽  
Supply Equipment ◽  
The Difference ◽  
And Performance

Compressed air is utilized throughout various production processes in the citrus industry and can influence production quality and operating costs. Within production equipment, compressed air is expanded from a higher pressure to perform various tasks. The pressure ahead of the final discharge location can have a direct impact on the operation of the specific process. Article pressure is the term used to describe the pressure located closest to the point where air is expanded to do work. Article pressure can be influenced by many variables that exist between supply equipment (compressors) and the point of use. Understanding the relationship between the supply pressure and the article pressure will facilitate the ability to maximize the repeatability and performance of production equipment and minimize the supply power required to operate the compressed air system. This paper will discuss variables that influence the difference between the pressure supplied by the compressor station and the pressure utilized within the production equipment. Illustrations and field examples will be utilized to describe issues. Troubleshooting methods will be discussed along with a description of how to trend variables that influence production so problems can be corrected before they influence productivity. Paper published with permission.

scholarly journals An efficient low cost-low technology whole household water collection and treatment system

2021 ◽  
Author(s):  
O. I. Okogwu ◽  
F. A. Elebe ◽  
G. N. Nwonumara
Keyword(s):  
Low Cost ◽  
Water Shortage ◽  
Total Coliform ◽  
Plate Count ◽  
Total Hardness ◽  
Chemical Contaminants ◽  
Technology System ◽  
Point Of Use ◽  
Borehole Water ◽  
Per Capita

Abstract Most residents in developing countries suffer severe water shortage and often resort to self-supply. Unfortunately, some self-supply water sources contain disease-causing biological and chemical contaminants and require point-of-use (POU) treatment. However, recontamination and persistence of chemical contaminants occur, which defeats the aim of POU. This study aims to develop an affordable low technology system that effectively treats whole-house water sourced from borehole and rain without recontamination. Raw borehole water (RBW) was treated with KAl(SO4)2.12H2O (8.10 mg/L), Ca(OH)2 (68.21 mg/L) and NaOCl (1.875 mg/L) in two separate tanks and thereafter filtered through 5-micron and 0.5-micron carbon filters, and reverse osmosis system. The results showed that heterotrophic plate count (2,700 CFU/mL) and total coliform (378.00±21.25 MPN/100 mL) in RBW were reduce to zero, and total hardness was reduced by >83% after treatment and there was no recontamination. Chromium (0.05±0.002 mg/L), Cu (0.04±0.001 mg/L), Pb (0.09±0.001 mg/L), Fe (0.26±0.005 mg/L) and Mn (0.2±0.001 mg/L) in the RBW were reduced below detectable limits after treatment. The annual per capita cost of water treatment was estimated at N4,744.44 ($9.32) at per capita consumption of 100 L/day. Our technology shows exceptional promises in providing affordable and safe water to the entire household throughout the year.

Auxiliary Heating of the Hands during Cold Exposure and Manual Performance

1971 ◽  
Vol 13 (5) ◽  
pp. 457-465 ◽  
Author(s):  
John M. Lockhart ◽  
Harold O. Kiess
Keyword(s):  
Ambient Temperature ◽  
Cold Exposure ◽  
Auxiliary Heating ◽  
Knot Tying ◽  
Performance Tasks ◽  
Impaired Performance ◽  
Ambient Temperature Condition ◽  
Significant Performance ◽  
Manual Tasks ◽  
Manual Performance

Twenty subjects performed five manual tasks barehanded during exposure to a 60°-F ambient temperature control condition, a 0°-F condition, and three ambient temperature conditions of 20°, 0°, and −20° F, in which auxiliary heat was applied to the hands. The tasks consisted of the Purdue Pegboard assembly, block-stringing, Minnesota Rate of Manipulation placing, knot-tying, and screw-tightening tasks and were performed after exposure durations of 0, 60, 120, and 180 min. Exposure to the 0°-F condition without auxiliary heat resulted in significant performance decrements on all tasks. The application of auxiliary heat to the hands resulted in the avoidance or alleviation of impaired performance during cold exposure depending upon the task, ambient temperature condition, and duration of exposure. The differential effects of auxiliary heat during cold exposure across manual performance tasks were related to the effects of auxiliary heat on hand skin temperature. These effects are discussed in terms of differential hand and finger dexterity, strength, and speed of movement requirements across tasks.

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