Effect of Filter Thickness on Efficiency of Sand Filter Water Quality Structure

1996 ◽  
Vol 31 (4) ◽  
pp. 801-808 ◽  
Author(s):  
F. Amini
Keyword(s):  
Water Quality ◽  
Fine Particles ◽  
Primary Objective ◽  
Confined Water ◽  
Sand Filter ◽  
Sediment Removal ◽  
Filter Structure ◽  
Filter Water ◽  
Filter Thickness ◽  
The Relationship

Abstract The primary objective of this study is to determine the relationship between the thickness of a sand filter and its effectiveness in removing fine particles suspended in water. To accomplish this objective, a physical model of a sand filter was built and designed to represent an underground confined water quality sand filter structure. Three types of sands, namely fine, medium and coarse, were used. The results indicated that the sediment removal efficiency for all sand thicknesses decreased with time. Within the range of variables studied, a thicker sand bed resulted in a more effective sand filter water quality structure.

Effect of Filter Media Particle Size Distribution on Filtration Efficiency

1998 ◽  
Vol 33 (4) ◽  
pp. 589-594 ◽  
Author(s):  
F. Amini ◽  
H.V. Truong
Keyword(s):  
Water Quality ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Removal Efficiency ◽  
Scale Model ◽  
Filter Media ◽  
Sand Filter ◽  
Sediment Removal ◽  
Filter Water

Abstract The results of an experimental study of a sand filter water quality model are presented. The model is built to represent an underground confined water quality sand filter structure. Three types of sands, namely fine, medium and coarse, were used to study the effect of filter media particle size distribution on sediment removal efficiency. The results indicated that the sediment removal efficiency for all sand types decreased with time. The use of medium sand provided the scale model filter with the highest sediment removal efficiency. The finding of this study indicates that the media grain size has a measurable effect on the efficiency of the sand filter water quality structure.

Optimization of Regional Water Quality Monitoring Strategies

1987 ◽  
Vol 19 (5-6) ◽  
pp. 721-727 ◽  
Author(s):  
J. Pintér ◽  
L. Somlyódy
Keyword(s):  
Water Quality ◽  
Water Quality Management ◽  
Water Quality Monitoring ◽  
Primary Objective ◽  
Lake Balaton ◽  
Monitoring Networks ◽  
Monitoring Strategies ◽  
Time Period ◽  
Computational Aspects ◽  
Indicator Model

A conceptual framework is presented for optimizing the operation of regional monitoring networks which assist water quality management. The primary objective of the studied network is to determine the annual nutrient load carried into a lake by its tributaries. Following the description of the basic (single time–period, single water quality indicator) model, several extension possibilities and computational aspects are highlighted. The suggested methodology is illustrated by a numerical example, concerning the surveillance system on the tributaries of Lake Balaton (Hungary).

The relationship between musty-odor-causing organisms and water quality in Lake Biwa

1995 ◽  
Vol 31 (11) ◽  
pp. 153-158 ◽  
Author(s):  
M. Kajino ◽  
K. Sakamoto
Keyword(s):  
Water Quality ◽  
Data Analysis ◽  
Green Algae ◽  
Analytical Methods ◽  
Lake Biwa ◽  
Blue Green Algae ◽  
Odor Compounds ◽  
Musty Odor ◽  
The Relationship

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.

The relationship between health effects in triathletes and microbiological quality of freshwater

1995 ◽  
Vol 31 (5-6) ◽  
pp. 19-26 ◽  
Author(s):  
G. J. Medema ◽  
I. A. van Asperen ◽  
J. M. Klokman-Houweling ◽  
A. Nooitgedagt ◽  
M. J. W. van de Laar ◽  
...  
Keyword(s):  
Water Quality ◽  
Geometric Mean ◽  
Microbiological Quality ◽  
Quality Parameters ◽  
Health Complaints ◽  
E Coli ◽  
Thermotolerant Coliforms ◽  
Microbiological Water Quality ◽  
The Relationship ◽  
Faecal Streptococci

This pilot study was carried out to determine the relationship between microbiological water quality parameters and the occurrence of health complaints among triathletes. Data were collected at an Olympic distance triathlon (n=314) and a run-bike-run (n=81; controls for exposure to fresh water). At the time of the triathlon, the concentrations of Escherichia coli , thermotolerant coliforms, faecal streptococci, entero- and reoviruses, F-specific RNA phages, Salmonella, Campylobacter, Aeromonas, Plesiomonas shigelloides, Pseudomonas aeruginosa and Staphylococcus aureus were examined over the swimming course. Information on the occurrence of health complaints during the competition and in the week thereafter was collected through a written questionnaire. The results show that triathletes and run-bike-runners are comparable with respect to factors other than water exposure (age, sex, training history, physical stress, lower intestinal health complaints during the competition) that may influence the occurrence of health complaints in the week after the competition. Triathletes and run-bike-runners reported gastro-intestinal (7.7% vs 2.5%), respiratory (5.5% vs 3.7%), skin/mucosal (2.6% vs 1.2%), general (3.5% vs 1.2%) and total symptoms (14.8% vs 7.4%) in the week after the event. The health risks for triathletes for all symptom groups are not significantly higher than for run-bike-runners. The geometric mean concentration of faecal indicator bacteria is relatively low: E. coli 170/100 ml; faecal streptococci 13/100 ml, enteroviruses were present at concentrations of 0.1/l. The group of triathletes was homogeneusly and relatively intensely exposed to water; they all swam in the same body of water at the same time and 75% reported to have swallowed freshwater. It was concluded that this study design is suitable to study the relationship between health complaints and microbiological water quality. In the summers of 1993 and 1994, a study will be carried out concerning several run-bike-runs and triathlons in freshwaters of different quality.

The effect of type of water supply on water quality in a developing community in South Africa

1997 ◽  
Vol 35 (11-12) ◽  
pp. 35-40 ◽  
Author(s):  
B. Genthe ◽  
N. Strauss ◽  
J. Seager ◽  
C. Vundule ◽  
F. Maforah ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Supply ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
E Coli ◽  
Guideline Values ◽  
Developing Communities ◽  
Quality Guideline ◽  
And Control ◽  
The Relationship

Efforts to provide water to developing communities in South Africa have resulted in various types of water supplies being used. This study examined the relationship between the type of water supply and the quality of water used. Source (communal taps, private outdoor and indoor taps) and point-of-use water samples were examined for heterotrophic plate counts (HPC), total and faecal coliforms, E. coli, and coliphages. Ten percent of samples were also analysed for enteric viruses, Giardia and Cryptosporidium. Approximately 320 households were included in a case-control study. In addition, a cross-sectional study was conducted. Both studies examined the relationship between different types of water facilities and diarrhoea among pre-school children. The source water was of good microbial quality, but water quality was found to have deteriorated significantly after handling and storage in both case and control households, exceeding drinking water quality guideline values by 1-6 orders of magnitude. Coliphage counts were low for all water samples tested. Enteric viruses and Cryptosporidium oocysts were not detected. Giardia cysts were detected on one occasion in case and control in-house samples. Comparisons of whether in-house water, after handling and storage, complied with water quality guideline values demonstrated households using communal taps to have significantly poorer quality than households using private outdoor or indoor taps for HPC and E. coli (χ2 = 14.9, P = 0.001; χ2 = 6.6, P = 0.04 respectively). A similar trend (although not statistically significant) was observed for the other microbial indicators. The cross-sectional study demonstrated an apparent decrease in health risk associated with private outdoor taps in comparison to communal taps. This study suggests that a private outdoor tap is the minimum level of water supply in order to ensure the supply of safe water to developing communities.

scholarly journals Assessing the Market for Poultry Litter in Georgia: Are Subsidies Needed to Protect Water Quality?

2011 ◽  
Vol 43 (4) ◽  
pp. 553-568 ◽  
Author(s):  
Jeffrey Mullen ◽  
Ulugbek Bekchanov ◽  
Berna Karali ◽  
David Kissel ◽  
Mark Risse ◽  
...  
Keyword(s):  
Water Quality ◽  
Poultry Litter ◽  
Focused Attention ◽  
Water Protection ◽  
Nutrient Loads ◽  
Transportation Model ◽  
Synthetic Fertilizer ◽  
Protection Goals ◽  
Subsidy Program ◽  
The Relationship

Concerns about nutrient loads into our waters have focused attention on poultry litter applications. Like many states with a large poultry industry, Georgia recently designed a subsidy program to facilitate the transportation of poultry litter out of vulnerable watersheds. This paper uses a transportation model to examine the necessity of a poultry litter subsidy to achieve water protection goals in Georgia. We also demonstrate the relationship between diesel and synthetic fertilizer prices and the value of poultry litter. Results suggest that a well-functioning market would be able to remove excess litter from vulnerable watersheds in the absence of a subsidy.

scholarly journals Effect of Maritime Traffic on Water Quality Parameters in Santa Marta, Colombia

2021 ◽  
Vol 9 (5) ◽  
pp. 474
Author(s):  
René Rodríguez-Grimón ◽  
Nestor Hernando Campos ◽  
Ítalo Braga Castro
Keyword(s):  
Water Quality ◽  
Petroleum Hydrocarbons ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Maritime Traffic ◽  
Natural Park ◽  
High Concentrations ◽  
The Impact ◽  
The Relationship ◽  
Multiple Chemical

Since 2013, there has been an increase (>23%) in naval traffic using maritime routes and ports on the coastal fringe of Santa Marta, Colombia. Of major concern, and described by several studies, is the relationship between maritime traffic and coastal contamination. This study proposed a maritime traffic indicator considering the simultaneous effects of several relevant measurements of water quality parameters to estimate the impact of naval activity. The approach involved developing a model including the number of vessels, hull length, and permanence time in berths. In addition, water quality variables, considering climatic seasons, were used to verify association with maritime traffic and touristic activities. The high concentrations of total coliforms (TC) and dissolved/dispersed petroleum hydrocarbons in chrysene equivalents (DDPH) reported by the International Marina of Santa Marta (SM) were affected by the local anthropic activities, including tourism, naval traffic, and urban wastewater discharges. Moreover, our results suggest the occurrence of multiple chemical impacts within Tayrona National Natural Park (PNNT) affecting conservation goals. The estimation of the maritime traffic indicator proposed in this study may be an easy and more complete tool for future studies evaluating the impact of naval activities on environmental quality.

scholarly journals Preoperative endothelial dysfunction in cutaneous microcirculation is associated with postoperative organ injury after cardiac surgery using extracorporeal circulation: a prospective cohort study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stanislas Abrard ◽  
Olivier Fouquet ◽  
Jérémie Riou ◽  
Emmanuel Rineau ◽  
Pierre Abraham ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Cohort Study ◽  
Endothelial Dysfunction ◽  
Postoperative Complications ◽  
Sofa Score ◽  
Primary Objective ◽  
Laser Speckle ◽  
Organ Injury ◽  
Contrast Imaging ◽  
The Relationship

Abstract Background Cardiac surgery is known to induce acute endothelial dysfunction, which may be central to the pathophysiology of postoperative complications. Preoperative endothelial dysfunction could also be implicated in the pathophysiology of postoperative complications after cardiac surgery. However, the relationship between preoperative endothelial function and postoperative outcomes remains unknown. The primary objective was to describe the relationship between a preoperative microcirculatory dysfunction identified by iontophoresis of acetylcholine (ACh), and postoperative organ injury in patients scheduled for cardiac surgery using cardiopulmonary bypass (CPB). Methods Sixty patients undergoing elective cardiac surgery using CPB were included in the analysis of a prospective, observational, single-center cohort study conducted from January to April 2019. Preoperative microcirculation was assessed with reactivity tests on the forearm (iontophoresis of ACh and nitroprusside). Skin blood flow was measured by laser speckle contrast imaging. Postoperative organ injury, the primary outcome, was defined as a Sequential Organ Failure Assessment score (SOFA) 48 h after surgery greater than 3. Results Organ injury at 48 h occurred in 29 cases (48.3%). Patients with postoperative organ injury (SOFA score > 3 at 48 h) had a longer time to reach the peak of preoperative iontophoresis of acetylcholine (133 s [104–156] vs 98 s [76–139] than patients without, P = 0.016), whereas endothelium-independent vasodilation to nitroprusside was similar in both groups. Beyond the proposed threshold of 105 s for time to reach the peak of preoperative endothelium-dependent vasodilation, three times more patients presented organ dysfunction at 48 h (76% vs 24% below or equal 105 s). In multivariable model, the time to reach the peak during iontophoresis of acetylcholine was an independent predictor of postoperative organ injury (odds ratio = 4.81, 95% confidence interval [1.16–19.94]; P = 0.030). Conclusions Patients who postoperatively developed organ injury (SOFA score > 3 at 48 h) had preoperatively a longer time to reach the peak of endothelium-dependent vasodilation. Trial registration Clinical-Trials.gov, NCT03631797. Registered 15 August 2018, https://clinicaltrials.gov/ct2/show/NCT03631797

scholarly journals A study of the relationship between recreational use and water quality in the river.

1992 ◽  
Vol 20 ◽  
pp. 378-385 ◽  
Author(s):  
Yukihiro SHIMATANI ◽  
Takashi YASUMOTI ◽  
Tuneya CHIDA
Keyword(s):  
Water Quality ◽  
The Relationship ◽  
Recreational Use
Sign in / Sign up

Export Citation Format

Share Document