Traitement des eaux usées par coagulation-floculation avec recirculation des boues chimiques : Évaluation et validation à grande échelle

2000 ◽  
Vol 27 (4) ◽  
pp. 735-753
Author(s):  
Frédéric Monette ◽  
François G Brière ◽  
Michel Létourneau ◽  
Marc Duchesne ◽  
Robert Hausler
Keyword(s):  
Wastewater Treatment ◽  
Treatment Plant ◽  
Water Tank ◽  
Small Particles ◽  
Recycling Process ◽  
Sludge Recycling ◽  
Work Done ◽  
Chemical Sludge ◽  
Flocculation Process

Two sequences of tests were carried out at the Centre d'épuration Rive-Sud wastewater treatment plant (Longueuil, Que.) to evaluate the performances of a coagulation-flocculation process with chemical sludge recycling. The tests consisted in following the evolution of the quality of the treated water when two flowsheets are supplied simultaneously in parallel with the same wastewater, one flowsheet incorporating the sludge recycling process. Results showed that the recycled sludge contributes significantly to water degradation compared with a classical coagulation-flocculation system. These results do not corroborate the previous work done by Monette et al. (F. Monette et al. Canadian Journal of Civil Engineering, 27: 702-718, 719-734, 2000). The problems observed are explained by inadequate plant installations for sludge recycling. High coagulant concentrations also limit the gains in efficiency associated with recyling. The process reacts rapidly to wastewater loading and reagent modifications. The recycled sludge conditioning is slightly more difficult because of the small particles created by recycling pump turbulence. Finally, turbidity measurements in the flocculator water tank could be used as an excellent indicator for sludge recycling load estimation.Key words: recycling, sludge, coagulation-flocculation, treatment, wastewater, full scale.

Traitement des eaux usées par coagulation-floculation avec recirculation des boues chimiques : Influence des réactifs

2000 ◽  
Vol 27 (4) ◽  
pp. 719-734
Author(s):  
Frédéric Monette ◽  
François G Brière ◽  
Michel Létourneau ◽  
Marc Duchesne ◽  
Robert Hausler
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Pollutant Removal ◽  
Sludge Recycling ◽  
Chemical Sludge ◽  
Flocculation Process

Three series of tests were carried out at laboratory and pilot levels to examine the functions of reagents (coagulant, flocculant, sludge) involved in a coagulation-flocculation process with chemical sludge recycling. Results showed that the recycled sludge participates favourably in the process. The gains in efficiency are particularely significant for lower coagulant concentrations when flocculant concentration is not limitative. The pollutant removal increases with the sludge recycling load but seems reversible and dependent on coagulant concentration. Results also revealed the advantages of recycling sludge before injecting coagulant. To decrease the total chemical costs at a wastewater treatment plant, the strategy must focus on diminishing the coagulant concentration and increasing the flocculant concentration while maintaining a sufficient recycling sludge load to ensure gains in efficiency.Key words: recycling, sludge, preformed flocs, reagents, coagulation-flocculation, treatment, wastewater.

Traitement des eaux usées par coagulation-floculation avec recirculation des boues chimiques : Performance générale et stabilité du procédé

2000 ◽  
Vol 27 (4) ◽  
pp. 702-718
Author(s):  
Frédéric Monette ◽  
François G Brière ◽  
Michel Létourneau ◽  
Marc Duchesne ◽  
Robert Hausler
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Normal Plant ◽  
Plant Operation ◽  
Load Variations ◽  
Sludge Recycling ◽  
The Stability ◽  
Chemical Sludge ◽  
Flocculation Process

Six series of tests were carried out to have a better understanding of the stability and efficiency of a coagulation-flocculation process with chemical sludge recycling. The tests consisted in sequential sludge recycling in 100-L pilot reactors. Other tests were performed to examine the stability following wastewater loading variations. Results showed that stability was reached immediately during the first recycling sequences. Furthermore, to obtain improved results compared with those of a classical coagulation-flocculation process, the flocculant concentration must be increased according to the sludge recycling load. Results also revealed that recycling sludge does not absorb wastewater load variations. Consequently, the implementation of sludge recycling in a wastewater treatment plant would not cause effluent degradation or entail major changes in a normal plant operation routine. The predominant coagulation-flocculation mechanisms that explained the increase in efficiency, in comparison with the classical process, were identified as enmeshment and sweep flocculation. Finally, the recycled sludge produced were conditioned and dewatered in a fashion similar to that of a classical process.Key words: recycling, sludge, preformed flocs, coagulation-flocculation, treatment, wastewater, stability.

Water quality of the Beli Lom river

1999 ◽  
Vol 39 (8) ◽  
pp. 55-62 ◽  
Author(s):  
Anastasios I. Stamou ◽  
Bogdana Koumanova ◽  
Stoyan Stoyanov ◽  
Georgy Atanasov ◽  
Konstantinos Pipilis
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Finite Difference ◽  
Treatment Plant ◽  
Quality Characteristics ◽  
Order Model ◽  
The Third ◽  
Do Concentration

A general methodology for the study of water quality in rivers is presented. The paper consists of four parts. In the first part the general characteristics of the area of study, which is the Beli Lom river, and its major pollution sources are presented. The effluent of the Razgrad Wastewater Treatment Plant (RWWTP) has been identified as the most significant pollution point source, due to the inadequate performance of the plant. The second part deals with data collection and processing. Four series of data have been collected, including physical, flow and water quality characteristics. In the third part a 1-d, finite-difference, second-order model is presented. In the fourth part, the model is calibrated, for the determination of its main coefficients, and is successfully verified by predicting the BOD and DO concentrations in the Beli Lom river for all series of data. Finally, the model has been applied to determine the maximum BOD and minimum DO effluent concentrations of the RWWTP, so that a minimum DO concentration is maintained throughout the river.

scholarly journals Assessment of the effects of wastewater treatment plant effluents on receiving streams using oligochaete communities of the porous matrix

2019 ◽  
pp. 18
Author(s):  
Régis Vivien ◽  
Michel Lafont ◽  
Inge Werner ◽  
Mélanie Laluc ◽  
Benoit J.D. Ferrari
Keyword(s):  
Wastewater Treatment ◽  
Surface Water ◽  
Hyporheic Zone ◽  
Surface Sediments ◽  
Treatment Plant ◽  
Functional Trait ◽  
Porous Matrix ◽  
Biological Quality ◽  
Coarse Surface

Human activities can disturb the natural dynamics of exchanges between surface water and groundwater in rivers. Such exchanges contribute to the self-purification of the environment and an excess of infiltration can lead to contamination of groundwater. In addition, the porous matrix (coarse surface sediments and hyporheic zone), through which water exchanges occur, is a sink for pollutants. For environmental monitoring programs, it is therefore essential to take into account both the dynamics of vertical hydrological exchanges and the biological quality of this matrix. The functional trait (FTR) method, which is based on the study of oligochaete communities in coarse surface sediments and the hyporheic zone, was proposed as a tool to simultaneously assess the dynamics of vertical hydrological exchanges and the effects of pollutants present in the porous matrix. Here, we applied this method during two different periods (in March and September 2016), upstream and downstream of locations affected by discharges from wastewater treatment plants (WWTP) located in Switzerland. The biological quality of surface sediments and the hyporheic zone was shown to be better upstream of the WWTP in both campaigns. In addition, results suggested that the capacity for self-purification was lower downstream of the WWTP, and that groundwater at these locations was vulnerable to pollution by surface water. The FTR method proved valuable as a field method for detecting the effects of point source contamination on receiving streams. In the near future, this community-based approach will benefit from advances in the use of DNA barcodes for oligochaete species identification.

scholarly journals Solutions for increasing the quality of hydro-technical building elements obtained by numerical simulation

2019 ◽  
Vol 85 ◽  
pp. 02011
Author(s):  
Alexandru Fodorean ◽  
Adrian Cureu ◽  
Oana Giurgiu ◽  
Dan Opruţa
Keyword(s):  
Waste Water ◽  
Numerical Simulation ◽  
Wastewater Treatment ◽  
Numerical Simulations ◽  
Numerical Models ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Design Phase

Sewage treatment remains a delicate subject and requires technical improvements to increase the efficiency of the systems responsible for the treatment. Numerical simulations are also a very useful tool, especially if they are used during the design phase. Thus, the paper aims to present the results obtained by CFD numerical simulations in the case of an important element within an existing wastewater treatment plant, namely the waste water treatment well, thus obtaining constructive solutions of a better functionally to the designed version. Through these, the work demonstrates the necessity of analyzes with CFD methods during design of the main elements of hydrotechnical constructions, but also the necessity of adjusting the numerical models with results obtained from experiments, measurements. The results show that the modifications described in the paper would bring significant improvements in waste disposal.

scholarly journals Assessment of wastewater treatment plant effluent impact on the ecosystem of the river on the basis of the quantitative development of ciliated protozoa characteristic of the aeration tank

2020 ◽  
Author(s):  
R. Babko ◽  
V. Pliashechnyk ◽  
T. Kuzmina ◽  
Y. Danko ◽  
J. Szulżyk-Cieplak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Waste Treatment ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Quantitative Characteristics ◽  
Quantitative Development ◽  
Treatment Facilities ◽  
The Impact

Abstract The work is devoted to the task of simplifying the assessment of the effect of effluents from treatment facilities on the river hydrobiocenosis. The studies were carried out on the mountain river Uzh (Uzhgorod, Ukraine). Our approach to assessing the impact of waste treatment facilities on the river receiver is based on the estimate of the similarity of species composition and quantitative characteristics of populations of organisms from the aerotank and from the river. It is shown that the quantitative development of populations of species of ciliates from the aeration tank is a good indicator for assessing the degradation of organic matter coming with wastewater. The use of qualitative and quantitative characteristics of the protozoa from the wastewater treatment plant as a criterion for assessing the quality of the environment in the area of wastewater discharge showed their representativeness and effectiveness. The use of a limited number of species makes it possible to conduct an express assessment of the effect of effluents on receiving reservoirs for specialists working with activated sludge in the laboratories of treatment facilities.

scholarly journals Antibiotics in WWTP discharge into the Chaobai River, Beijing

2016 ◽  
Vol 42 (4) ◽  
pp. 48-57 ◽  
Author(s):  
Zhang Chunhui ◽  
Wang Liangliang ◽  
Gao Xiangyu ◽  
He Xudan
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Treatment Plant ◽  
Water Quality Monitoring ◽  
Environmental Distribution ◽  
Receiving River ◽  
Dominant Point ◽  
Aerated Filter ◽  
Beijing China

Abstract22 representative antibiotics, including 8 quinolones (QNs), 9 sulfonamides (SAs), and 5 macrolides (MCs) were selected to investigate their occurrence and removal efficiencies in a Wastewater Treatment Plant (WWTP) and their distribution in the receiving water of the Chaobai River in Beijing, China. Water quality monitoring was performed in an integrated way at different selected points in the WWTP to explore the potential mechanism of antibiotics removal during wastewater treatment. Water quality of the Chaobai River was also analyzed to examine environmental distribution in a river ecosystem. The results showed that within all the 22 compounds examined, 10 antibiotics were quantified in wastewater influent, 10 in effluent, and 7 in river. Sulfadiazine (SDZ, 396 ng/L) and Sulfamethazine (SMZ, 382 ng/L) were the dominating antibiotics in the influent. Both the conventional treatment and advanced Biological Aerated Filter (BAF) system was important for the removal of antibiotics from the wastewater. And the concentrations of selected antibiotics were ranged from 0-41.8 ng/L in the effluent-receiving river. Despite the fact that the concentrations were reduced more than 50% compared to effluent concentrations, WWTP discharge was still regarded as a dominant point-source input of antibiotics into the Chaobai River.

Removal of cyanobacterial metabolites through wastewater treatment plant filters

2012 ◽  
Vol 65 (7) ◽  
pp. 1244-1251 ◽  
Author(s):  
Lionel Ho ◽  
Daniel Hoefel ◽  
Charlotte Grasset ◽  
Sebastien Palazot ◽  
Gayle Newcombe ◽  
...  
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Activated Carbon ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Filter Medium ◽  
Sand Filtration ◽  
Sand Filter ◽  
High Nutrient

Wastewaters have the potential to proliferate excessive numbers of cyanobacteria due to high nutrient levels. This could translate to the production of metabolites, such as the saxitoxins, geosmin and 2-methylisoborneol (MIB), which can impair the quality of wastewater destined for re-use. Biological sand filtration was assessed for its ability to remove these metabolites from a wastewater. Results indicated that the sand filter was incapable of effectively removing the saxitoxins and in some instances, the effluent of the sand filter displayed greater toxicity than the influent. Conversely, the sand filter was able to effectively remove geosmin and MIB, with removal attributed to biodegradation. Granular activated carbon was employed as an alternative filter medium to remove the saxitoxins. Results showed similar removals to previous drinking water studies, where efficient removals were initially observed, followed by a decrease in the removal; a consequence of the presence of competing organics which reduced adsorption of the saxitoxins.

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