Optimization of Artificial Wetland Design for Removal of Indicator Microorganisms and Pathogenic Protozoa

1999 ◽  
Vol 40 (4-5) ◽  
pp. 363-368 ◽  
Author(s):  
C. P. Gerba ◽  
J. A. Thurston ◽  
J. A. Falabi ◽  
P. M. Watt ◽  
M. M. Karpiscak
Keyword(s):  
Subsurface Flow ◽  
Individual Performance ◽  
Surface Flow ◽  
Enteric Pathogens ◽  
Fecal Coliforms ◽  
Treatment Level ◽  
Artificial Wetland ◽  
Indicator Microorganisms ◽  
Duckweed Pond ◽  
Wetland Design

The enhancement of water quality by artificial wetland systems is increasingly being employed throughout the world. Three wetlands were studied in Tucson, AZ to evaluate their individual performance in the removal of indicator bacteria (coliforms), coliphage, and enteric pathogens (Giardia and Cryptosporidium). A duckweed-covered pond, a multi-species subsurface flow (SSF) and a multi-species surface flow (SF) wetland were studied. Removal of the larger microorganisms, Giardia and Cryptosporidium, was the greatest in the duckweed pond at 98 and 89 percent, respectively. The lowest removal occurred in the SF wetland, 73 percent for Giardia and 58 percent removal for Cryptosporidium. In contrast, the greatest removal of coliphage, total and fecal coliforms occurred in the SSF wetland, 95, 99, and 98 percent respectively, whereas the pond had the lowest removals (40, 62, and 61 percent, respectively). Sedimentation may be the primary removal mechanism within the duckweed pond since the removal was related to size, removal of the largest organisms being the greatest. However, the smaller microorganisms were removed more efficiently in the SSF wetland, which may be related to the large surface area available for adsorption and filtration. This study suggests that in order to achieve the highest treatment level of secondary unchlorinated wastewater, a combination of aquatic ponds and subsurface flow wetlands may be necessary.

Water Quality of Swimming Pools in Jerusalem

1993 ◽  
Vol 27 (7-8) ◽  
pp. 287-294 ◽  
Author(s):  
S. Lerman ◽  
O. Lev ◽  
A. Adin ◽  
E. Katzenelson
Keyword(s):  
Water Quality ◽  
Fecal Coliforms ◽  
Pathogenic Microorganisms ◽  
Swimming Pools ◽  
Indicator Organisms ◽  
Indicator Microorganisms ◽  
E Coli ◽  
Safe Water ◽  
Indirect Information

The Israel Ministry of Health is now revising its regulations for the assurance of safe water quality in public swimming pools. Since it is not possible to monitor each of the pathogenic microorganisms, it is often recommended to monitor indicator bacteria which provide indirect information on the water quality in the swimming pool. Three indicator microorganisms are often recommended: coliform counts (total coliforms, fecal coliforms or E. Coli), staphylococcus aureus and pseudomonas aeruginosa. A four year survey of the water quality of swimming pools in the Jerusalem District was conducted in order to determine whether the monitoring of all three indicators is necessary to assure safe water quality or is it sufficient to monitor only a single microorganism. A statistical analysis, conducted by using several different statistical techniques, reveals that the populations of the three indicator organisms are significantly interdependent but the correlations between each pair of these indicators are not sufficient to base a prediction of any of the organisms based on the measurements of the others. Therefore, it is concluded that monitoring of all three indicators should be recommended in order to provide an adequate picture of the water quality in swimming pools.

scholarly journals Post-treatment of tannery wastewater using pilot scale horizontal subsurface flow constructed wetlands (polishing)

2017 ◽  
Vol 77 (4) ◽  
pp. 988-998 ◽  
Author(s):  
Tadesse Alemu ◽  
Andualem Mekonnen ◽  
Seyoum Leta
Keyword(s):  
Removal Efficiency ◽  
Batch Reactor ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Surface Flow ◽  
Tannery Wastewater ◽  
Treated Effluent ◽  
Horizontal Subsurface Flow ◽  
Pollutants Removal

Abstract In the present study, a pilot scale horizontal subsurface flow constructed wetland (CW) system planted with Phragmites karka; longitudinal profile was studied. The wetland was fed with tannery wastewater, pretreated in a two-stage anaerobic digester followed by a sequence batch reactor. Samples from each CW were taken and analyzed using standard methods. The removal efficiency of the CW system in terms of biological oxygen demand (BOD), chemical oxygen demand (COD), Cr and total coliforms were 91.3%, 90%, 97.3% and 99%, respectively. The removal efficiency for TN, NO3− and NH4+-N were 77.7%, 66.3% and 67.7%, respectively. Similarly, the removal efficiency of SO42−, S2− and total suspended solids (TSS) were 71.8%, 88.7% and 81.2%, respectively. The concentration of COD, BOD, TN, NO3−N, NH4+-N, SO42 and S2− in the final treated effluent were 113.2 ± 52, 56 ± 18, 49.3 ± 13, 22.75 ± 20, 17.1 ± 6.75, 88 ± 120 and 0.4 ± 0.44 mg/L, respectively. Pollutants removal was decreased in the first 12 m and increased along the CW cells. P. karka development in the first cell of CW was poor, small in size and experiencing chlorosis, but clogging was higher in this area due to high organic matter settling, causing a partial surface flow. The performance of the pilot CW as a tertiary treatment showed that the effluent meets the permissible discharge standards.

Separation of surface flow from subsurface flow in catchments using runoff coefficient

2021 ◽  
Author(s):  
A. Afshar Ardekani ◽  
T. Sabzevari ◽  
A. Torabi Haghighi ◽  
A. Petroselli
Keyword(s):  
Subsurface Flow ◽  
Surface Flow ◽  
Runoff Coefficient

scholarly journals Effects of Using an Alternative Bedding Composition on the Levels of Indicator Microorganisms and Mammary Health in Dairy Farm Conditions

Agriculture ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 245
Author(s):  
František Zigo ◽  
Nad’a Sasáková ◽  
Gabriela Gregová ◽  
Jana Výrostková ◽  
Silvia Ondrašovičová
Keyword(s):  
Dairy Cows ◽  
Dairy Farm ◽  
Subclinical Mastitis ◽  
Mammary Glands ◽  
Fecal Coliforms ◽  
Time Intervals ◽  
Indicator Microorganisms ◽  
Actual Observation ◽  
Positive Effect ◽  
Observation Period

The aim of this study was to compare an improved bedding composition with conventional straw bedding under farm conditions, regarding its effects on the influence of indicator microorganisms on the hygiene levels of cubicle floors and the occurrence of mastitis in dairy cows. Dairy cows were housed in newly built stalls divided into two parts, each with four subsections, and bedded cubicles arranged in three rows. Five stall subsections from each 9-bedded cubicle were selected for study, and 30 dairy cows were monitored according to the time intervals of bedding treatment for cubicles. In the first subsection (control), the cows were housed in bedded cubicles layered with straw up to a height of 20 cm. Sections 2–5 had alternative bedding (AB) as follows: fresh AB, AB 1 month old, AB 2 months old, and AB 3 months old, which were bedded one day before (fresh) and 1–3 months before the actual observation period, respectively. The alternative bedding per one cubicle consisted of ground limestone (100 kg), water (80 L), recycled manure solids (RMS; 15 kg), and straw (25 kg). After laying, the bedding was treated with a concrete selector to provide strength and sufficient resistance. A total of 180 bedding and 600 quarter milk samples were taken simultaneously from all five monitored subsections for microbiological determination. Comparing classical straw bedding with the alternate bedding showed a stabilizing effect by keeping the bedding thickness up to the floor barrier level, which had a beneficial effect by reducing the level of fecal contamination in the rear of the cubicle. Fecal coliforms and fecal streptococci were found to be reduced in one-day-old bedding as well as after the first, second, and third months. By evaluating the health status of the mammary glands, a positive effect was noted in reducing the occurrence of subclinical mastitis, which was reflected in a reduced number of infected quarters in the group of cows housed in cubicles for three months after use of improved bedding.

A critical evaluation of a pilot scale subsurface flow wetland: 10 years after commissioning

1997 ◽  
Vol 35 (5) ◽  
pp. 337-343 ◽  
Author(s):  
Allan Batchelor ◽  
Pierre Loots
Keyword(s):  
Critical Evaluation ◽  
Subsurface Flow ◽  
Plug Flow ◽  
Pilot Scale ◽  
Preliminary Evidence ◽  
Surface Flow ◽  
Organic Load ◽  
Hydraulic Load ◽  
Flow Through ◽  
Back Mixing

A pilot scale subsurface flow wetland, commissioned in 1986, has been continuously operated since 1990 at a hydraulic load of 330 mm/day and a corresponding organic load of 1200 kg/ha·day. At these loading rates preliminary evidence suggests that the microbial biomass in the wetland was dominated by anaerobes. Attempts to increase the hydraulic load resulted in surface flooding which was attributed to suspended solids clogging the surface. Despite short circuiting, revealed by tracer studies, COD removal exceeded 70%. The hydraulic flow through the wetland was modelled and was described as modified plug flow with a degree of back mixing. A comparative costing exercise revealed that the unit treatment cost of a combination of a subsurface flow wetland/nitrification column, surface flow wetland was lower than that of an activated sludge system treating the same volume of effluent.

Occurrence of Enteric Bacteria and Viruses in Oysters

1980 ◽  
Vol 43 (2) ◽  
pp. 111-113 ◽  
Author(s):  
MARK D. SOBSEY ◽  
CAMERON R. HACKNEY ◽  
ROBERT J. CARRICK ◽  
BIBEK RAY ◽  
MARVIN L. SPECK
Keyword(s):  
Fecal Coliform ◽  
Enteric Bacteria ◽  
Total Coliform ◽  
Fecal Pollution ◽  
Enteric Pathogens ◽  
The Other ◽  
Fecal Coliforms ◽  
Sample Collection ◽  
Closed Area ◽  
Vibrio Parahemolyticus

Enteric bacteria and virus levels were determined in oysters from paired stations that were opened or closed for commercial shellfishing on the basis of total coliform levels in the water. Six pairs of stations were sampled quarterly over a 1-year period. Enteric viruses were found in 3 of 24 50-g oyster samples from closed areas and in none of 23 samples from open areas. Salmonella was found in 2 of 47 samples of 40 g each, one from an open and the other from a closed area. Although enteric pathogens of fecal origin were found only in oysters that exceeded the recommended market limit of 230 fecal coliforms per 100 g of meat, the fecal coliform levels in some virus-positive samples were much lower than those in Salmonella-positive samples. Vibrio parahemolyticus levels were similar in oysters from both open and closed beds, indicating no particular association with fecal pollution. However, there was a marked seasonal variation in V. parahemolyticus levels. Total but not fecal coliform levels in oysters from open beds correlated with the occurrence of rainfall 1 or 2 days before sample collection. Neither total nor fecal coliform levels in oysters from closed beds correlated with rainfall. These findings suggest that fecal coliforms levels in oysters are less influenced by rainfall than are total coliforms, and therefore may be a more specific indicator of recent fecal pollution.

scholarly journals Flow–Sediment Turbulent Ejections: Interaction between Surface and Subsurface Flow in Gravel-Bed Contaminated by Fine Sediment

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1589
Author(s):  
Bustamante-Penagos N. ◽  
Niño Y.
Keyword(s):  
Subsurface Flow ◽  
Power Spectra ◽  
Surface Current ◽  
Streamwise Velocity ◽  
Fine Sediment ◽  
Surface Flow ◽  
Subsurface Water ◽  
Turbulent Structures ◽  
Before And After ◽  
Scatter Plots

Several researchers have studied turbulent structures, such as ejections, sweeps, and outwards and inwards interactions in flumes, where the streamwise velocity dominates over vertical and transversal velocities. However, this research presents an experimental study in which there are ejections associated with the interchange between surface and subsurface water, where the vertical velocity dominates over the streamwise component. The experiment is related to a surface alluvial stream that is polluted with fine sediment, which is percolated into the bed. The subsurface flow is modified by a lower permeability associated with the fine sediment and emerges to the surface current. Quasi-steady ejections are produced that drag fine sediment into the surface flow. Particle image velocimetry (PIV) measured the velocity field before and after the ejection. The velocity data were analyzed by scatter plots, power spectra, and wavelet analysis of turbulent fluctuations, finding changes in the distribution of turbulence interactions with and without the presence of fine deposits. The flow sediment ejection changes the patterns of turbulent structures and the distribution of the turbulence interactions that have been reported in open channels without subsurface flows.

Analysis on the Ecological Restoration Technology

2013 ◽  
Vol 438-439 ◽  
pp. 1282-1285
Author(s):  
Jing Xia Liu ◽  
Huai Jing Wu ◽  
Zeng Qiang An
Keyword(s):  
Engineering Design ◽  
Ecological Restoration ◽  
Surface Flow ◽  
Flow Unit ◽  
Natural Habitats ◽  
Artificial Wetland ◽  
Engineering Measures ◽  
Wetland Treatment ◽  
Ecological Improvement

On the analysis of worldwide situation of river ecological restoration, this paper takes the Jialu River in Zhengzhou city as an example, carries out the study on ecological improvement of traditional river projects in six aspects, such as the arrangement of watercourse plane and section morphology, the design of ecological revetment engineering course, the engineering measures to create artificial imitation of natural habitats, the shallow surface flow unit engineering design of wetland and artificial wetland treatment, the protection and combing with floodplain woodland and the plants disposition of waterfront area. The results may provide the reference for the ecological restoration technology.

Influence of design, physico-chemical and environmental parameters on pharmaceuticals and fragrances removal by constructed wetlands

2011 ◽  
Vol 63 (11) ◽  
pp. 2527-2534 ◽  
Author(s):  
M. Hijosa-Valsero ◽  
V. Matamoros ◽  
R. Sidrach-Cardona ◽  
A. Pedescoll ◽  
J. Martín-Villacorta ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Environmental Parameters ◽  
Primary Treatment ◽  
Surface Flow ◽  
Full Scale ◽  
Design Parameters ◽  
Physico Chemical ◽  
Positive Correlations

The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater was assessed. The results of three previous works were considered as a whole to find common patterns in PPCP removal. The experiment took place outdoors under winter and summer conditions. The mesocosm-scale CWs differed in some design parameters, namely the presence of plants, the vegetal species chosen (Typha angustifolia versus Phragmites australis), the flow configuration (surface flow versus subsurface flow), the primary treatment (sedimentation tank versus HUSB), the feeding regime (batch flow versus continuous saturation) and the presence of gravel bed. The full-scale CWs consisted of a combination of various subsystems (ponds, surface flow CWs and subsurface flow CWs). The studied PPCPs were ketoprofen, naproxen, ibuprofen, diclofenac, salicylic acid, carbamazepine, caffeine, methyl dihydrojasmonate, galaxolide and tonalide. The performance of the evaluated treatment systems was compound dependent and varied as a function of the CW-configuration. In addition, PPCP removal efficiencies were lower during winter. The presence of plants favoured naproxen, ibuprofen, diclofenac, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide removal. Significant positive correlations were observed between the removal of most PPCPs and temperature or redox potential. Accordingly, microbiological pathways appear to be the most likely degradation route for the target PPCPs in the CWs studied.

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