Study of Flow Pattern in Jet Clarifier for Removal of Turbidity by Residence Time Distribution Approach

Romphophak, Ploypailin; Wongwailikhit, Kritchart; Chawaloesphonsiya, Nattawin; Samornkraisorakit, Pornsak; Painmanakul, Pisut

doi:10.4186/ej.2016.20.2.17

Cited by 9 publications

(9 citation statements)

References 12 publications

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“…High-efficiency clarifiers such as Densadeg, Multiflo and Actiglo have been introduced and applied in many water plants in China since 2005 [1][2][3][4][5][6]. In the operation, the flocs were deposited on the bottom plate on the side of the sedimentation tank in a plant.…”

Section: Introductionmentioning

confidence: 99%

Large-scale hydraulic optimization of high-efficiency clarifiers in water plants

Zhang

Wang

Jiang

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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In order to reveal the hydraulic reasons for the uneven distribution of water flow and velocity in the high-efficiency clarification tank, and the hydraulic reasons for the deposition of sediment on one side, CFD was used to simulate the overall tank. The three-dimensional simulation results showed that without any baffle, the velocity was extremely uneven, and the rotation of the stirring blade around the axis produced a velocity loop, which resulted in a large backflow of the velocity. There were obvious differences in flocs and water flow through the two holes. After adding the existing baffles, the water flow and floc concentration could be much more uniform, but there was still sludge sediment on one side. After further lengthening the existing baffles outside the cylinder and adding 45° baffles in the transition section of the coagulation tank and the sedimentation tank, the inconsistency of flow velocity and floc concentration could be basically solved.

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Section: Introductionmentioning

confidence: 99%

Large-scale hydraulic optimization of high-efficiency clarifiers in water plants

Zhang

Wang

Jiang

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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“…Jet velocity plays an important role in determining the high pressure and discharge required to achieve fluidization conditions. The role of the jet stream, has even been developed by Ploypailin Romphophak et.al [21] to dispose of water turbidity.…”

Section: Introductionmentioning

confidence: 99%

Minimum Jet Velocity for Unbounded Domain Fluidization as a New Dredging Methods

Thaha

Triatmadja

Yuwono

et al. 2018

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Unlike for the bounded domain, the minimum fluidization velocity of the unbounded fluidization domain has not been well developed. The aimed of the research is to formulate the minimum jet (holes) velocity (voc) theoretically and experimentally as the criteria for unbounded domain fluidization. Physical experiments were conducted for bounded and unbounded fluidizations of 20 cm to 45 cm thickness of sand bed. The bounded fluidization was carried out using a transparent vertical tube, whilst the unbounded fluidization was conducted on a transparent box. The fluidization discharge and pressure were measured. Empirical equations on jet holes velocity based on the experiment was developed. It was found that voc depends on the required superficial velocity at the surface of sediment deposit (vc) and flow rate loose factor () due to unbounded domain conditions. The vc is greater than the minimum fluidization velocity in bounded domain (vmf). The conservative values of velocity conversion factor (ks) were found to be approximately 2.0.

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“…The main available data are generally presented in terms of turbidity removal and their conclusions do not converge on all points. Romphophak et al (2016) studied the effect of flow rate used on the jet clarifier to reduce the turbid synthetic water: it was concluded that efficiency of about 80% can be achieved at the flow rates of 40 -180 L/h (60000 < Gt < 90000). Kumar et al (2009) showed that, for square and circular flocculators (37000 < Gt < 60000), the turbidity removal was maximum when the nozzle was located 50% of the height of the tank and that when the detention time increases the residual turbidity sharply falls.…”

Section: Mixing and Flocculation In Jet Clarifiermentioning

confidence: 99%

“…and the reactor base, and the height of the sludge blanket is 25 cm. for the LSP that is shown in Figure 2.1 (a) (Romphophak, 2013). Nevertheless, the diameter of the truncated cone's base might be another important factor since it might affect the flocculation zone directly has not still evaluated yet; therefore, it would be evaluated to evaluate its effect on flocculation and fill the research gap.…”

Section: Efficiencymentioning

confidence: 99%

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Effects of configuration and operating conditions on turbidity removal of jet clarifier

Romphophak

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In water treatment, flocculation creates large and weighty flocs enough to be removed by the downstream processes of sedimentation and filtration. Among the various existing technologies, the jet clarifier is considered as an effective and compact system as it couples flocculation and clarification in a single unit. For the design of jet mixing, much experimental work has been done and many correlations have been proposed. However, these correlations are case specifics, and, to date, there is no comprehensive view for the flocculation aspect. In order to evaluate the performance of the jet clarifier for turbidity removal and understand hydrodynamics to propose the optimal operating conditions and design criteria, two different configurations of the continuous jet clarifiers are figured out. The first one is a prototype of a 3D jet clarifier studied at two scales and implemented at Samsen Water Treatment Plant, Thailand; these two reactors were designed to investigate the performance and mean Residence Time Distribution (RTD) for various injected flow rates. The results indicated no effect of reactor sizes, and a reduction of the initial turbidity (50 NTU) was achieved with an efficiency of approximately 80% under optimal conditions. Moreover, the second jet clarifier configuration was designed as a Quasi-2Dimensional (Q2D) jet clarifier at the TBI-INSA-Toulouse, France allowing the application of optical metrological methods used to understand better local phenomena controlling the efficiency of the jet clarifier. Hence, measurements of instantaneous velocity field were performed by means of Particle Image Velocimetry (PIV). The processing of experimental PIV data highlighted a strong circulation induced by the jet in the flocculation zone. At this location, the range of velocity gradient (G) is 3 to 13 s-1 whereas the residence time decreases from 4 to 1 hour. Based on the hydrodynamic analysis, the Camp number (Gt) in the flocculation zone is shown to be constant at around 7,000 for different jet flow rates (from 11L/hr to 49L/hr). The efficiency of such the jet clarifier can thus be foreseen. Plus, measurements of the number of flocs and their size distributions were performed by means of shadowgraphy and image analysis. Thanks to a coupling between the different experimental results obtained in the Q2D jet clarifier, it was possible to relate the evolution of the number of flocs along the jet to the recirculation loop present in the flocculation zone. The relative independence of the floc size distributions on the flow rate is discussed in light of the Camp number, which can explain the efficiency of the jet clarifier in terms of flocculation. Finally, due to reactor design, the simulations using CFD code showing encouraging results were presented at the end of the manuscript. Here as well, characteristic time scales and velocity gradient were used to perform the first comparisons.

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Study of Flow Pattern in Jet Clarifier for Removal of Turbidity by Residence Time Distribution Approach

Cited by 9 publications

References 12 publications

Large-scale hydraulic optimization of high-efficiency clarifiers in water plants

Large-scale hydraulic optimization of high-efficiency clarifiers in water plants

Minimum Jet Velocity for Unbounded Domain Fluidization as a New Dredging Methods

Effects of configuration and operating conditions on turbidity removal of jet clarifier

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