Modélisation du comportement des matières en suspension à l'effluent d'un décanteur primaire lamellaire

1993 ◽  
Vol 20 (5) ◽  
pp. 767-777
Author(s):  
P. Lessard ◽  
D. Martel ◽  
B. Desjardins
Keyword(s):  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Model Performance ◽  
Suspended Solid ◽  
Lumped Parameter Model ◽  
Concentration Data ◽  
Stirred Tank Reactors ◽  
Wide Range ◽  
Suspended Solid Concentration ◽  
In Series

Process modelling can prove a useful tool for the control of wastewater treatment plants. The objective of this research was to verify that a primary settling model developped for a conventional process is applicable to a process using lamellar settling. The lumped-parameter model examines the hydraulics of a system composed of stirred tank reactors in series and simulates suspended solid concentration of the effluent under various flow regimes. The model has been validated using data collected from a pilot lamella settler of a capacity of 15 m3 and operated over a wide range of flows (Hazen velocity between 0,43 and 2,59 m∙h−1). The prediction of the model was in agreement with the observed values both in terms of concentration and hydraulic behavior of effluent suspended solids (average relative error of 17%). How ever, less satisfactory was the model performance tested with the concentration data on settleable solids. Research is under way to study the different mechanisms of sedimentation going on in the settler. Key words: modelling, lamellar settling, settleable suspended solids.

Distribution of Organic Contaminants in Water and Suspended Solids of the Rainy River

1988 ◽  
Vol 23 (4) ◽  
pp. 590-601 ◽  
Author(s):  
John C. Merriman
Keyword(s):  
Organic Contaminants ◽  
Kraft Pulp ◽  
Suspended Solids ◽  
Suspended Solid ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Bleached Kraft Pulp ◽  
Dioxins And Furans ◽  
Wide Range ◽  
Polycyclic Aromatic

Abstract Water and suspended solid samples were collected in 1986 at three stations on the Rainy River and from the final effluents of two bleached kraft pulp and paper mills discharging into the river. A wide range of organic contaminants were analysed, including organochlorine pesticides (OCs), total PCBs, chlorobenzenes (CBs), polycyclic aromatic hydrocarbons (PAHs) and chlorophenols (CPs). Suspended solids were also analysed for dioxins and furans. Analysis of the data indicated that for the most part, compounds were below the detection limit at the upstream end of the river. High levels of PCBs, dioxins, furans, CPs and PAHs were found in mill effluents, which resulted in some elevated concentrations in the Rainy River downstream of the mills. At the downstream end of the river, there was no impact evident for the compounds analysed.

Reduced Hydraulic Detention Time for Complete Nutrient Removal with Innovative Biological Reactors

1991 ◽  
Vol 24 (10) ◽  
pp. 217-229 ◽  
Author(s):  
F. Rogalla ◽  
M. Payraudeau ◽  
P. Sauvegrain ◽  
J. Sibony
Keyword(s):  
Nutrient Removal ◽  
Western Europe ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Nitrogen And Phosphorus ◽  
Solids Retention ◽  
In Series ◽  
Reduced Space ◽  
Limiting Parameters

To limit pollution discharges through wastewater into surface waters, increasingly stringent effluent standards particularly for nutrient removal require extensive upgrading of conventional wastewater treatment plants. Large sewage treatment plants in Western Europe are often located in densely urbanised areas where land is unavailable. To avoid additional unit processes for nitrogen and phosphorus removal, innovative solutions are demonstrated. A compact reactor is presented that achieves low pollutant residuals (carbonaceous matter, suspended solids, nitrogen and phosphorus) in reduced space and a few examples of full scale applications are given. Through extensive pilots tests, the limiting parameters for nutrient removal are established on sewage after pretreatment and lamella settling. The biological treatment by two granular filters in series combines biodegradation and suspended solids retention without further particle separation. The anoxic reactor removal rates varied between 0.3 and 1.5 kg N-NO3/m3 d, depending on temperature and available carbon. Nitrification on the aerobic filter increases from 0.3 kg to 1 kg N-NH4/m3 d with temperature in a range between 5 to 20 °C. Total nitrogen residuals below 10 mg/l and effluent phosphorus below 1 mg/l can be achieved with hydraulic retention times of around 3 hours.

scholarly journals F-Specific RNA Bacteriophage Transport in Stream Water: Hydro-Meteorological Controls and Association with Suspended Solids

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2250
Author(s):  
Núria Martínez-Carreras ◽  
Leslie Ogorzaly ◽  
Cécile Walczak ◽  
Christophe Merlin ◽  
Emmanuelle Montargès-Pelletier ◽  
...  
Keyword(s):  
Time Scales ◽  
Suspended Solids ◽  
Stream Water ◽  
Water Discharge ◽  
Model Performance ◽  
Suspended Solid ◽  
Driving Factors ◽  
Storm Runoff ◽  
Low Flows ◽  
Runoff Events

F-specific RNA bacteriophages (FRNAPHs) are commonly used as indicators of faecal and viral contamination in waters. Once they enter surface waters, the exact role of suspended solids, sediments and hydro-meteorological factors in their fluvial fate and transport is poorly understood, and long-term studies (e.g., over years) are lacking. In this study, FRNAPH concentrations and genogroup distribution were measured in the Orne River (France) during two years at weekly intervals, and during four storm runoff events. Hydro-meteorological driving factors were investigated at both time scales. FRNAPH concentrations and genogroups at different depths of a riverbank sediment core were also examined to better discriminate the origin of the faecal pollution. During low flows, the FRNAPH and the suspended solid transport were decoupled and the FRNAPH concentrations were mainly correlated with the air and water temperature. During storm runoff events, the FRNAPH concentrations only showed a significant correlation with conductivity, turbidity and water discharge. Despite the uncertainty of the predictions, multi parameter regression models using hydro-meteorological variables were suitable to predict log transformed FRNAPHs’ concentrations at low flows with a standard error of 0.46. Model performance using the storm runoff events dataset was low. This study highlights different driving factors at low flows and during storm runoff events, and the need to measure at both time scales to better understand phage transport dynamics in surface water.

Nanofiltration of endocrine disrupting compounds

2003 ◽  
Vol 3 (5-6) ◽  
pp. 321-327 ◽  
Author(s):  
M. Gallenkemper ◽  
T. Wintgens ◽  
T. Melin
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Endocrine Disrupting Compounds ◽  
Municipal Wastewater Treatment ◽  
Water And Wastewater Treatment ◽  
Wide Range ◽  
Endocrine Disrupting ◽  
Municipal Wastewater Treatment Plants ◽  
Set Up

Endocrine disrupting compounds can affect the hormone system in organisms. A wide range of endocrine disrupters were found in sewage and effluents of municipal wastewater treatment plants. Toxicological evaluations indicate that conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. Nanofiltration provides high quality permeates in water and wastewater treatment. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention for nonylphenol (NP) and bisphenol A (BPA) ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. The retention of BPA was found to be inversely proportional to the membrane permeability.

Performance Analysis of the Rotating Biological Contactor Process Based on Particle Fraction and Improvement of Final Effluent Quality

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1457-1466 ◽  
Author(s):  
Kazuhiro Tanaka ◽  
Minoru Tada ◽  
Mitsuo Ito ◽  
Noritugu Shimizu
Keyword(s):  
Suspended Solids ◽  
Fine Particles ◽  
Wastewater Treatment Plants ◽  
Small Scale ◽  
Particle Fraction ◽  
Effluent Quality ◽  
Rotating Biological Contactors ◽  
Activated Sludge Processes ◽  
Fraction Method ◽  
Final Effluent

Biofilm processes are, in general, suitable for small-scale wastewater treatment plants. However, final effluent qualities of biofilm processes are not as good as those of activated sludge processes due to fine particles remaining in the effluents. To improve the effluent qualities of the Rotating Biological Contactors (RBC) process, the behavior of fine particles through the process and the removal of fine particles with solids-liquid separation methods, rapid filtration and coagulation-filtration, were investigated using the particle fraction method. The results are as follows:–An increase of the hydraulic retention time (HRT) in the RBC reactor reduced the amount of fine particles and increased the amount of coarse suspended solids of 44 µm or more in diameter, which are easily removed by clarification. Thus, the final effluent qualities were improved by the increase of HRT.–Suspended solids in effluent from the RBC process at the standard loading are so fine that improvement of the quality is not expected by only lowering the overflow rate of a final clarifier. In contrast, rapid filtration or a coagulation-filtration process is effective. The supended solid concentration and transparency of the effluent from the final clarifier was improved by a factor of two to four, and then BOD of the final effluent was removed by 40-85%.

scholarly journals The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO2 Powders

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 999 ◽  
Author(s):  
Aranza Denisse Vital-Grappin ◽  
Maria Camila Ariza-Tarazona ◽  
Valeria Montserrat Luna-Hernández ◽  
Juan Francisco Villarreal-Chiu ◽  
Juan Manuel Hernández-López ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Reaction System ◽  
Terrestrial Ecosystems ◽  
Degradation Process ◽  
Reactive Species ◽  
Hazardous Substances ◽  
Wide Range ◽  
Degradation Behaviors ◽  
Environmentally Friendly Process

Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e−), hydroxyl (OH●), and superoxide ion (O2●−) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species’ role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●− and e− scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e− plays an essential role in the MPs’ degradation. Furthermore, the degradation behaviors observed when h+ and O2●− were removed from the reaction system suggest that these species can also perform the initiating step of degradation.

Removal improvement of bacteria (Escherichia coli and enterococci) in maturation ponds using baffles

2012 ◽  
Vol 65 (4) ◽  
pp. 589-595 ◽  
Author(s):  
A. Ouali ◽  
H. Jupsin ◽  
J. L. Vasel ◽  
L. Marouani ◽  
A. Ghrabi
Keyword(s):  
Escherichia Coli ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
E Coli ◽  
Conventional Activated Sludge ◽  
In Series ◽  
Hydrodynamic Study ◽  
Rhodamine Wt ◽  
Engineering Intervention

Korba wastewater treatment plant is a conventional activated sludge followed by three maturation ponds (MP1, MP2, MP3) in series acting as a tertiary treatment. The first study of wastewater treatment plants showed that the effluent concentration of Escherichia coli and enterococci at the outlet of the (MP3) varies between 103 and 104CFU/100 ml. After the hydrodynamic study conducted by Rhodamine WT which showed short-circuiting in the MP1, two baffles were introduced in the first maturation pond (MP1) to improve the hydrodynamic and the sanitary performances. The second hydraulic study showed that the dispersion number ‘d’ was reduced from 1.45 to 0.43 by this engineering intervention and the Peclet number was raised from 0.69 to 2.32. The hydraulic retention time was increased by 14 h. Because of well-designed baffles, the removal efficiency of E. coli and enterococci was raised between 0.2 and 0.7 log units for the first maturation pond.

Numerical Simulation of Droplet Generation in Series Co-Flow Capillaries

2009 ◽  
Author(s):  
Yanxi Song ◽  
Jinliang Xu
Keyword(s):  
Reynolds Number ◽  
Disperse Phase ◽  
Weber Number ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Disperse Flow ◽  
Double Emulsions ◽  
Wide Range ◽  
In Series ◽  
Dispersed Phases

We study the production and motion of monodisperse double emulsions in microfluidics comprising series co-flow capillaries. Both two and three dimensional simulations are performed. Flow was determined by dimensionless parameters, i.e., Reynolds number and Weber number of continuous and dispersed phases. The co-flow generated droplets are sensitive to the Reynolds number and Weber number of the continuous phase, but insensitive to those of the disperse phase. Because the inner and outer drops are generate by separate co-flow processes, sizes of both inner and outer drops can be controlled by adjusting Re and We for the continuous phase. Meanwhile, the disperse phase has little effect on drop size, thus a desirable generation frequency of inner drop can be reached by merely adjusting flow rate of the inner fluid, leading to desirable number of inner drops encapsulated by the outer drop. Thus highly monodisperse double emulsions are obtained. It was found that only in dripping mode can droplet be of high mono-dispersity. Flow begins to transit from dripping regime to jetting regime when the Re number is decreased or Weber number is increased. To ensure that all the droplets are produced over a wide range of running parameters, tiny tapered tip outlet for the disperse flow should be applied. Smaller the tapered tip, wider range for Re and we can apply.

Small Screen, Big Feels

2020 ◽  
Author(s):  
Melissa Ames
Keyword(s):  
United States ◽  
The United States ◽  
Presidential Debates ◽  
Audience Studies ◽  
The Walking Dead ◽  
Wide Range ◽  
In Series ◽  
Fear And Anxiety ◽  
Small Screen ◽  
Network Era

While television has always played a role in recording and curating history, shaping cultural memory, and influencing public sentiment, the changing nature of the medium in the post-network era finds viewers experiencing and participating in this process in new ways. They skim through commercials, live tweet press conferences and award shows, and tune into reality shows to escape reality. This new era, defined by the heightened anxiety and fear ushered in by 9/11, has been documented by our media consumption, production, and reaction. In Small Screen, Big Feels, Melissa Ames asserts that TV has been instrumental in cultivating a shared memory of emotionally charged events unfolding in the United States since September 11, 2001. She analyzes specific shows and genres to illustrate the ways in which cultural fears are embedded into our entertainment in series such as The Walking Dead and Lost or critiqued through programs like The Daily Show. In the final section of the book, Ames provides three audience studies that showcase how viewers consume and circulate emotions in the post-network era: analyses of live tweets from Shonda Rhimes's drama, How to Get Away with Murder (2010--2020), ABC's reality franchises, The Bachelor (2002--present) and The Bachelorette (2003--present), and political coverage of the 2016 Presidential Debates. Though film has been closely studied through the lens of affect theory, little research has been done to apply the same methods to television. Engaging an impressively wide range of texts, genres, media, and formats, Ames offers a trenchant analysis of how televisual programming in the United States responded to and reinforced a cultural climate grounded in fear and anxiety.

OPTIMIZING OPERATION OF WASTEWATER TREATMENT PLANTS BY OFFLINE AND ONLINE COMPUTER SIMULATION

1994 ◽  
Vol 30 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Ralf Otterpohl ◽  
Thomas Rolfs ◽  
Jörg Londong
Keyword(s):  
Computer Simulation ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Historical Analysis ◽  
Computer Work ◽  
Biological Phosphorus Removal ◽  
Wide Range

Computer simulation of activated sludge plant for nitrogen removal has become a reliable tool to predict the behaviour of the plant Models including biological phosphorus removal still require some practical experience but they should be available soon. This will offer an even wider range than today's work with nitrogen removal. One major benefit of computer simulation of wastewater treatment plants (WTP) is the optimization of operation. This can be done offline if hydrographs of a plant are collected and computer work is done with “historical” analysis. With online simulation the system is fed with hydrographs up to the actual time. Prognosis can be done from the moment of the computer work based on usual hydrographs. The work of the authors shows how accuratly a treatment plant can be described, when many parameters are measured and available as hydrographs. A very careful description of all details of the special plant is essential, requiring a flexible simulation tool. Based on the accurate simulation a wide range of operational decisions can be evaluated. It was possible to demonstrate that the overall efficiency in nitrogen removal and energy consumption of ml activated sludge plant can be improved.

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