Application of CFD modelling to study the hydrodynamics of various anaerobic pond configurations

2003 ◽  
Vol 48 (2) ◽  
pp. 163-171 ◽  
Author(s):  
G.P. Vega ◽  
M.R. Peña ◽  
C. Ramírez ◽  
D.D. Mara
Keyword(s):  
Full Scale ◽  
Two Dimensional ◽  
Cfd Modelling ◽  
Waste Stabilization Ponds ◽  
Hydrodynamic Efficiency ◽  
Advection Dispersion ◽  
Waste Stabilization ◽  
Breadth Ratio ◽  
Dispersion Patterns ◽  
Dynamic Variables

The simulation of hydrodynamics and transport phenomena in waste stabilization ponds is a developing tool worth studying in order to understand their internal processes and interactions. Pond design involves several physical, hydrological, geometric and dynamic variables so as to provide high hydrodynamic efficiency and maximum substrate utilization rates. CFD modelling allows the combination of these factors to predict the behaviour of ponds having different configurations. The two-dimensional depth-integrated model MIKE 21 was used in this study to simulate hydrodynamic and advection-dispersion processes in a full-scale anaerobic pond (AP) located in southwest Colombia. A set of 12 configurations including sludge contents, inlet-outlet positioning, baffling and pond geometry were modelled. Results showed that a crosswise (diagonally opposite) inlet-outlet layout, a length-to-breadth ratio of 2:1, plus provision of two cross baffles at 1/3 L and 2/3 L were the most effective measures to improve overall AP hydrodynamics and dispersion patterns.

Microalgal luxury uptake of phosphorus in waste stabilization ponds – frequency of occurrence and high performing genera

2017 ◽  
Vol 78 (1) ◽  
pp. 165-173 ◽  
Author(s):  
A. Crimp ◽  
N. Brown ◽  
A. Shilton
Keyword(s):  
Phosphorus Content ◽  
Microscopic Analysis ◽  
Full Scale ◽  
High Rate ◽  
Waste Stabilization Ponds ◽  
High Performing ◽  
Dissolved Phosphorus ◽  
Climatic Regions ◽  
Stabilization Ponds ◽  
Waste Stabilization

Abstract Microalgae commonly found in waste stabilization ponds (WSPs) are able to accumulate elevated phosphorus levels within their cells in a process known as luxury uptake. However, there are few studies focused on luxury uptake in full scale WSPs. In order to comprehensively quantify the occurrence of this phenomenon, eight different WSP sites comprising seven primary facultative, six maturation and two high rate algal ponds (HRAPs) spread over several climatic regions were monitored over four seasons. Of the 15 ponds studied, 13 of these exhibited elevated levels of biomass phosphorus content at some point; however, the occurrence in HRAPs was limited. More than half of the samples tested had elevated phosphorus contents and this occurred in all climatic zones surveyed. The phosphorus content of the biomass was significantly correlated to decreasing rainfall and increasing total dissolved phosphorus. Microscopic analysis revealed that nearly all the 17 microalgal and five cyanobacterial genera identified performed luxury uptake, but at varying frequencies. This is the first time that the genera of algae responsible for luxury uptake in full scale WSPs has been studied. Chlamydomonas/Cryptomonas, Micractinium/Microcystis and Scenedesmus were the only microalgal genera found to both commonly occur in WSPs and consistently perform luxury uptake.

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.

Performance evaluation of 388 full-scale waste stabilization pond systems with seven different configurations

2016 ◽  
Vol 75 (4) ◽  
pp. 916-927 ◽  
Author(s):  
Maria Fernanda Espinosa ◽  
Marcos von Sperling ◽  
Matthew E. Verbyla
Keyword(s):  
System Performance ◽  
Oxygen Demand ◽  
The United States ◽  
Ammonia Nitrogen ◽  
Full Scale ◽  
Future Research ◽  
Waste Stabilization Ponds ◽  
Waste Stabilization ◽  
Thermotolerant Coliforms ◽  
Removal Efficiencies

Waste stabilization ponds (WSPs) and their variants are one the most widely used wastewater treatment systems in the world. However, the scarcity of systematic performance data from full-scale plants has led to challenges associated with their design. The objective of this research was to assess the performance of 388 full-scale WSP systems located in Brazil, Ecuador, Bolivia and the United States through the statistical analysis of available monitoring data. Descriptive statistics were calculated of the influent and effluent concentrations and the removal efficiencies for 5-day biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonia nitrogen (N-Ammonia), and either thermotolerant coliforms (TTC) or Escherichia coli for each WSP system, leading to a broad characterization of actual treatment performance. Compliance with different water quality and system performance goals was also evaluated. The treatment plants were subdivided into seven different categories, according to their units and flowsheet. The median influent concentrations of BOD5 and TSS were 431 mg/L and 397 mg/L and the effluent concentrations varied from technology to technology, but median values were 50 mg/L and 47 mg/L, respectively. The median removal efficiencies were 85% for BOD5 and 75% for TSS. The overall removals of TTC and E. coli were 1.74 and 1.63 log10 units, respectively. Future research is needed to better understand the influence of design, operational and environmental factors on WSP system performance.

Dispersion patterns of zooplankton in two waste stabilization ponds

1982 ◽  
Vol 33 (6) ◽  
pp. 1123 ◽  
Author(s):  
BD Mitchell ◽  
WD Williams
Keyword(s):  
Aquatic Macrophytes ◽  
Sampling Unit ◽  
Waste Stabilization Ponds ◽  
Stabilization Ponds ◽  
Waste Stabilization ◽  
Dispersion Patterns ◽  
Littoral Species

The dominant zooplankters in waste stabilization ponds at Gumeracha were contagiously distributed on both small and gross scales. Individuals were never randomly distributed on a scale defined by the sampling unit. Overall patchiness of littoral species was more pronounced in the presence of high standing crops of aquatic macrophytes. Other possible causes of contagion in zooplankters are briefly discussed.

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 .

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