Modification of Rhodamine WT tracer tests procedure in activated sludge reactors

Tracer tests with rhodamine WT were performed at the biggest wastewater treatment plant of Mexico (‘Dulces Nombres’ WWTP, 5 m3/s). The aim was to develop the hydraulics sub-model to represent the aeration tanks, in the context of a project for calibrating the activated sludge model N°1 (ASM1). The planning of the experiment was performed by pre-simulation in AQUASIM, which allowed determining the quantities of dye (8 L per reactor) and sampling schedule that were required. After the tests, the rhodamine concentration profiles of the outlet mixed liquors were fit with different alternative of tank mixing models. Simulating the tracer data allowed to estimate the unknown influent flows, as well as determine the best hydraulics model: 4 completely stirred tank reactors retro-connected through the RAS (return activated sludge).

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Mixing and Detention Time Distribution in Activated Sludge Tanks

Water Science & Technology ◽

10.2166/wst.1985.0130 ◽

1985 ◽

Vol 17 (2-3) ◽

pp. 197-208 ◽

Cited By ~ 11

Author(s):

H. Bode ◽

C. F. Seyfried

Keyword(s):

Activated Sludge ◽

Time Distribution ◽

Strong Influence ◽

Tracer Tests ◽

Tracer Test ◽

Evaluation Procedure ◽

Response Curves ◽

Detention Time ◽

Test Study ◽

Mixing Characteristics

The interrelationship between mixing characteristics and tracer response curves in activated sludge tanks is explained. In some cases the return sludge cycle has a strong influence on the tracer response curves. Results from tracer tests in the field are hard to interpret because the tracer in the return sludge interferes with the initial tracer. Therefore a special evaluation procedure has to be applied. The paper closes with results from a field tracer test study.

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Full activated sludge model no. 1 calibration experience at a medium-size WWTP in Mexico

Water Science & Technology ◽

10.2166/wst.2009.747 ◽

2009 ◽

Vol 60 (12) ◽

pp. 3069-3082 ◽

Cited By ~ 4

Author(s):

C. Fall ◽

J. Loaiza-Navia ◽

M. Esparza-Soto

Keyword(s):

Activated Sludge ◽

Tracer Tests ◽

Medium Size ◽

Carbon And Nitrogen ◽

North East ◽

The North ◽

Influent Characterization ◽

Comprehensive Modeling ◽

Sludge Settling

As part of the efforts done to introduce the practice of modeling in Latin America, this research carried out at the North-East WWTP of Monterrey represents the first comprehensive modeling case in Mexico. The main objective was to reproduce the organic carbon removal and sludge production rates of the plant, based on ASM1. Different intermediate studies were performed prior to the calibration of the model: influent characterization, tracer tests and hydraulics modeling, sludge settling tests and respirometry. Two fractionation methods (STOWA protocol and Influent-advisor) were compared, showing no equivalent patterns. A stepwise sequence of calibration was developed and successfully applied. The hydraulics of the reactors at the plant was reproduced by use of a series of 3 to 5 CSTRs. The waste and return activated sludge flowrates (QWAS and QRAS) were corrected based on the inorganic and total suspended solids mass balances. The Vesilind settling constants were measured (Vo and rhind), while the flocculent zone settling parameter (rfloc) was adjusted to calibrate the secondary clarifier. In ASM1, the adjusted parameters were the COD soluble inert fraction (frSI) and the particulate substrate fraction (FrXS). All other ASM1 parameters were kept at their default values. The steady-state calibrated model (in GPS-X) adequately described the quality of the effluent (carbon and nitrogen) as well as the sludge composition (M. Liquor and WAS). This case study provides voluntarily detailed data to allow its wide use for training and teaching purposes.

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Short circuiting in a denitrifying activated sludge tank

Water Science & Technology ◽

10.2166/wst.2005.0681 ◽

2005 ◽

Vol 52 (10-11) ◽

pp. 79-87 ◽

Cited By ~ 8

Author(s):

R. Kjellstrand ◽

A. Mattsson ◽

C. Niklasson ◽

M.J. Taherzadeh

Keyword(s):

Activated Sludge ◽

Short Circuit ◽

Lithium Concentration ◽

Tracer Tests ◽

Maximum Flow ◽

Dead Volume ◽

Mean Velocity ◽

Stirred Tank Reactors ◽

In Series ◽

The Mean

The presence of a short circuit flow in a denitrifying activated sludge tank was identified and modelled. Tracer tests with pulse addition of lithium salt were used to investigate the hydraulics of the tank. The lithium concentration in the effluent was detected and residence time distribution (RTD) curves were generated. Hydraulic models based on completely stirred tank reactors (CSTRs) in series were generated from the RTD curves and the models were compared. The short circuit problem was successfully described using the Martin model, where the inflow is divided into two strands. Each strand was modelled as a number of CSTRs in series. At a normal flow the results of the model show that the tank has 12.8% dead volume, 85.8% main volume and 1.3% short circuiting volume. The inflow was divided into 91.9% entering the main volume and 8.1% entering the short circuiting volume. The mean velocity of the short circuiting stream was estimated to 0.4m/s. At maximum flow the short circuiting stream was even larger and handled 24.3% of the flow. The short circuiting stream was identified in the upper part of the tank due to the position of the inlet and the outlet. The configuration of a tank including the use of baffles, the geometry of the inlet and mixer configuration should be considered carefully if short circuiting is to be avoided.

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Regulations, legislation, and guidelines for artificial surface water and groundwater tracer tests in Canada

Water Quality Research Journal ◽

10.2166/wqrjc.2012.042 ◽

2012 ◽

Vol 47 (1) ◽

pp. 42-55 ◽

Cited By ~ 5

Author(s):

Christian Wolkersdorfer ◽

Jenna LeBlanc

Keyword(s):

Newfoundland And Labrador ◽

Tracer Tests ◽

Tracer Test ◽

Sodium Fluorescein ◽

Environment Canada ◽

Canadian Province ◽

Quality Guidelines ◽

Artificial Surface ◽

Rhodamine Wt ◽

Fisheries Act

This paper describes Canadian federal and provincial regulations, legislation, and guidelines for artificial tracer tests, where substances are released into water, and provides a world-wide comparison. Alberta is currently the only Canadian province with guidelines and regulations relating to those tests. None of the other provinces have specific tracer test regulations in place, though the injection of artificial substances into waters is covered by Section 36(3) of the federal Fisheries Act. Newfoundland and Labrador, the Northwest Territories, and Nunavut sometimes require a permit to conduct a tracer test, and Quebec is planning to implement guidelines and regulations based on Michigan/USA Environmental Quality guidelines. In each case Fisheries and Oceans Canada (DFO), Environment Canada, and the Provincial environment departments should be contacted and the proposed test described as detailed as necessary. We present potential tracers, such as uranine (sodium fluorescein), or Rhodamine WT, that can be used in artificial tracer tests. This study is the result of contacting personnel from organizations such as Environment Canada, Fisheries and Oceans Canada, provincial departments of environment, researchers, and consultants.

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Hydrodynamics of vertical subsurface flow constructed wetlands: Tracer tests with rhodamine WT and numerical modelling

Ecological Engineering ◽

10.1016/j.ecoleng.2008.06.004 ◽

2009 ◽

Vol 35 (2) ◽

pp. 265-273 ◽

Cited By ~ 41

Author(s):

David Giraldi ◽

Mattia de’Michieli Vitturi ◽

Mattia Zaramella ◽

Andrea Marion ◽

Renato Iannelli

Keyword(s):

Numerical Modelling ◽

Constructed Wetlands ◽

Subsurface Flow ◽

Tracer Tests ◽

Rhodamine Wt ◽

Subsurface Flow Constructed Wetlands

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Investigations On Water Circulation in Animal Sea-Water Basins – On the Example of Seals′ Breeding Pools

Polish Maritime Research ◽

10.1515/pomr-2017-0042 ◽

2017 ◽

Vol 24 (s1) ◽

pp. 224-229 ◽

Cited By ~ 3

Author(s):

Piotr Zima

Keyword(s):

Velocity Vector ◽

Sea Water ◽

Tracer Tests ◽

Water Circulation ◽

Applied Model ◽

Finite Differences Method ◽

2D Flow ◽

Marine Station ◽

Rhodamine Wt

Abstract This paper presents general comments concerning investigations on water circulation in animal breeding pools containing sea water. As an example are given results of computer simulation of water circulation in seals′ breeding pools situated in Marine Station at Hel, belonging to Oceanographic Institute , Gdansk University. A mathematical model of three main pools was prepared with taking into account their inflow and outflow water supply points. Next, the object indication ( tracer) tests were done with the use of mathematical modelling as well as in-situ measurements. For description of flow field in steady conditions a simplified model of 2D flow in the form of Helmholtz biharmonic equation of stream function , recalculated then into velocity vector components, was used. The equation , supplemented with appropriate boundary conditions , was solved numerically by using the finite differences method. The spreading of a substance dissolved in water (tracer) was analyzed by solving 2D equation of transient advecting - dispersing transport. To solve it the finite volumes method was applied. The applied model was verified by conducting the indication tests with the use of the rhodamine WT as a tracer. The obtained results made it possible to reconstruct water circulation within the seals′ pools and identify stagnation zones in which water circulation may be made difficult.

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