Fluid flow pattern and water residence time in waste stabilisation ponds

2009 ◽  
Vol 59 (6) ◽  
pp. 1061-1068 ◽  
Author(s):  
F. Badrot-Nico ◽  
V. Guinot ◽  
F. Brissaud
Keyword(s):  
Meteorological Data ◽  
Residence Times ◽  
Mixing Processes ◽  
Waste Stabilization Ponds ◽  
Waste Stabilisation Ponds ◽  
Wind Speeds ◽  
Treatment Processes ◽  
Waste Stabilization ◽  
Physically Based ◽  
Completely Stirred Tank Reactor

As treatment processes are kinetic-dependent, a consistent description of water residence times is essential to the prediction of waste stabilization ponds performance. A physically-based 3D transient CFD model simulating the water velocity, temperature and concentration fields as a function of all influent meteorological factors – wind speed and direction, solar radiation, air temperature and relative humidity – was used to identify the relationships between the meteorological conditions and the hydrodynamic patterns and water residence times distributions in a polishing pond. The required meteorological data were recorded on site and water temperatures recorded at 10 sampling sites for 141 days. Stratification events appear on very calm days for wind speeds lower than 3 m s−1 and on sunny days for wind speeds lower than 5 m s−1. De-stratification is related to two mixing processes: nightly convection cells and global mixing patterns. Numerical tracer experiments show that the results of the flow patterns can be evaluated using the dispersed flow regime approximation and, for wind speeds exceeding 6 m s−1, the completely stirred tank reactor assumption.

scholarly journals Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

2013 ◽  
Vol 10 (2) ◽  
pp. 2067-2088
Author(s):  
D. J. Barrington ◽  
A. Ghadouani ◽  
G. N. Ivey
Keyword(s):  
Hydrogen Peroxide ◽  
Full Scale ◽  
Management Technique ◽  
Waste Stabilization Ponds ◽  
Waste Stabilisation Ponds ◽  
Hydrogen Peroxide Treatment ◽  
Waste Stabilization ◽  
Cyanobacterial Species ◽  
Treatment Train ◽  
Term Management

Abstract. Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H2O2) for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs). The daily dynamics of cyanobacteria and microcystins (a commonly occurring cyanotoxin) were examined following the addition of H2O2 to wastewater within both the laboratory and at the full-scale within a WSP. Hydrogen peroxide treatment at concentrations ≥ 10−4 g H2O2 μg−1 of total phytoplankton chlorophyll a led to the death of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H2O2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial chlorophyta species was also observed within days of H2O2 addition. However, within weeks, the chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H2O2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

scholarly journals Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

2013 ◽  
Vol 17 (6) ◽  
pp. 2097-2105 ◽  
Author(s):  
D. J. Barrington ◽  
A. Ghadouani ◽  
G. N. Ivey
Keyword(s):  
Hydrogen Peroxide ◽  
Wastewater Treatment ◽  
Treatment Plant ◽  
Full Scale ◽  
Management Technique ◽  
Waste Stabilization Ponds ◽  
Waste Stabilisation Ponds ◽  
Hydrogen Peroxide Treatment ◽  
Waste Stabilization ◽  
Treatment Train

Abstract. Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H2O2) for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs). The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins) were examined following the addition of H2O2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H2O2 μg−1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H2O2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H2O2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H2O2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

A New Technique for the Enumeration of Rotaviruses in Wastewater Samples

1989 ◽  
Vol 21 (3) ◽  
pp. 99-104 ◽  
Author(s):  
J. I. Oragui ◽  
D. D. Mara ◽  
S. A. Silva ◽  
A. M. Konig
Keyword(s):  
Inorganic Ions ◽  
Assay Method ◽  
Toxic Substances ◽  
Waste Stabilization Ponds ◽  
Virus Removal ◽  
Molecular Weights ◽  
Large Numbers ◽  
Waste Stabilization ◽  
A New Technique ◽  
Wastewater Samples

Rotaviruses are generally excreted in large numbers in diarrhoeal stools, but in wastewaters their numbers are subject to variations. Detection and enumeration of these viruses involve a concentration step followed by an assay method. Enumeration in wastewater concentrates is complicated by the presence of toxic substances which are often concentrated with the viruses. These toxic substances often cause the destruction of cells during rotavirus assay, thus leading to underestimation of viral numbers. Such concentrates were detoxified by a simple and effective method using polyacrylamide (Biogel P-6DG) or dextran (Sephadex G50) beads. Concentrates (10 ml) were mixed with 0.5 g gel and the mixtures were allowed to stand for 2 h at room temperature during which time the beads swell by the passage of water into them along with inorganic ions and substances with molecular weights of less than 30,000. The supernatants were then decontaminated with antibiotics and assayed for rotaviruses by the indirect immunofluorescent technique. Most untreated ultrafiltrates of raw sewage and those from anaerobic ponds were found to be too toxic to MA104 and LLC MK2 cells, whereas the above treatment rendered over 90% of wastewater concentrates non-toxic to cells. This technique was used to study virus removal in samples from deep waste stabilization ponds in northeast Brazil.

Rotavirus removal in experimental waste stabilization pond systems with different geometries and configurations

1995 ◽  
Vol 31 (12) ◽  
pp. 285-290 ◽  
Author(s):  
J. I. Oragui ◽  
H. Arridge ◽  
D. D. Mara ◽  
H. W. Pearson ◽  
S. A. Silva
Keyword(s):  
Clostridium Perfringens ◽  
Slow Process ◽  
Faecal Coliforms ◽  
Waste Stabilization Ponds ◽  
Stabilization Pond ◽  
Waste Stabilization Pond ◽  
Stabilization Ponds ◽  
Waste Stabilization

Rotavirus removal in waste stabilization ponds is a relatively slow process: in a series of ten ponds (a 1-d anaerobic pond followed by nine 2-d ponds) its numbers were reduced from 1.4 × 105 per litre to zero, and in an “innovative” series (a 1-day anaerobic pond, 3-d facultative pond, 3.8-d, 3-d and 5-d maturation ponds) from 5.1 × 104 per litre to <5 per litre. Faecal coliforms were better indicators of rotaviruses than was Clostridium perfringens .

Waste stabilization ponds in France: a report on fifteen years experience

1995 ◽  
Vol 31 (12) ◽  
pp. 91-101 ◽  
Author(s):  
Y. Racault ◽  
C. Boutin ◽  
A. Seguin
Keyword(s):  
Load Level ◽  
Organic Load ◽  
Nitrogen And Phosphorus ◽  
Waste Stabilization Ponds ◽  
Sewerage System ◽  
System Type ◽  
Stabilization Ponds ◽  
Waste Stabilization ◽  
Output Load

In 1992, a survey was conducted on the performance of waste stabilization ponds in France. The data selected come from a sample of 178 ponds, with an average capacity of 600 p.e., throughout France. For each plant, one or several input--output load measurements over a 24-h period are available. The average organic load level received is approximately 25 kg BOD/ha.d, representing 50% of the nominal load. The quality of the treated water is presented based on the type of sewerage system feeding the ponds. The results appear dispersed, however; in 70% of the cases the concentrations in COD and BOD on filtered samples are under 120 mg/l and 40 mg/l, respectively, and the concentration in TSS under 120 mg/l (discharge standards in France for waste stabilization ponds). The reductions in nitrogen and phosphorus nutrients are on average from 60% to 70%. The influence of different parameters (sewerage system type, organic load, season, age of plant, etc.) was studied. The results appear noticeably worse when the ponds receive wastewater from a strictly separate sewerage system.

scholarly journals Evaluation of contaminants removal by waste stabilization ponds: A case study of Siloam WSPs in Vhembe District, South Africa

Heliyon ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. e06207
Author(s):  
Joshua N. Edokpayi ◽  
John O. Odiyo ◽  
Oluwaseun E. Popoola ◽  
Titus A.M. Msagati
Keyword(s):  
South Africa ◽  
Waste Stabilization Ponds ◽  
Stabilization Ponds ◽  
Waste Stabilization ◽  
Contaminants Removal ◽  
Vhembe District
Sign in / Sign up

Export Citation Format

Share Document