Prediction of aeration performance of paddle wheel aerators

Moulick, Sanjib; Mal, B. C.; Bandyopadhyay, Sambaran

doi:10.1016/s0144-8609(01)00087-5

Cited by 44 publications

(21 citation statements)

References 9 publications

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“…Moulick et al (2002) obtained similar results when adjusting mixing speed in a paddle wheel aerator. Clarke et al (2006) tested the effects of alkalinity on the oxygen transfer coefficient in a New Brunswick bioreactor and found that the effects of alkalinity were tied to the speed of the impeller.…”

Section: Immersion Depthmentioning

confidence: 55%

“…Moulick et al (2002) found the immersion depth of a paddle wheel aerator to have a significant effect on aeration. Al-Ahmady (2006) investigated the oxygen transfer capacity in a bench scale subsurface aerator and found that by increasing the water depth the average bubble residence time increased allowing more time for oxygen transfer to occur.…”

Section: Immersion Depthmentioning

confidence: 99%

“…The ditch essentially consists of a closed loop, open channel in which liquid circulation and oxygen input are maintained by a mechanical device. The disc aerator described by (Wu, 1995;Gomolka and Gomolka, 1991;Ghaly and Kok, 1986) is an alternative to the brush and paddle wheel rotors which are traditionally used in oxidation ditches (Moulick et al, 2002;Jones et al, 1971). It has certain advantages with regard to foam generation but the oxygenation capacity of an individual disc was reported to be limited and the use of a number of discs on the rotating shaft was suggested in order to allow for a wider range of oxygenation capacities (Drews et al, 1972).…”

Section: Introductionmentioning

confidence: 99%

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Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

Ghaly¹

2011

American Journal of Applied Sciences

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Problem statement:The oxidation ditch system has been used to treat various types of wastewaters. Several types of aerators are used to supply the treatment process with oxygen. Among these devices, the disc aerator has certain advantages regarding foam generation over the brush and paddle type rotors, but the main disadvantages of this aerator is the limited oxygenation capacity. The main objectives of this study were to study the effects of various design parameters and system operation parameters on the oxygenation capacity of the system. Approach: A bench scale oxidation ditch system equipped with a disc aerator was used to gain better understanding of the phenomena of oxygen transfer and to study the effects of hole diameter, number of holes per disc, disc thickness, disc speed, immersion depth and number of discs on the oxygenation capacity of the system. The unsteady state method with sulphite oxidation was used to deoxygenate the water. The test involved chemical removal of dissolved oxygen from water followed by oxygenation. The power consumed was measured, the oxygen transfer coefficient was determined and both the oxygenation capacity and oxygenation efficiency were calculated. Results: The oxygen transfer coefficient was affected by the immersion depth, hole diameter, disc speed, disc thickness and number of discs, with the disc speed having the greatest effect. The results showed that three physical processes simultaneously contributed to oxygen transfer by the disc aerator: bubble aeration, eddy aeration and surface aeration. Conclusion: The use of sodium sulphite with cobalt chloride for deoxygenation of the water via the oxidation ditch was effective and the results were very consistent and repeatable. The aerator disc of 2.55 cm thickness, 1.92 cm diameter and 48 holes was found to achieve the highest oxygenation capacity. The system is anticipated to provide a broad range of oxygen transfer rates under actual conditions (23-164 mgO 2 /L-h) to meet varying process demands encountered in aerobic treatment systems.

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Section: Immersion Depthmentioning

confidence: 55%

Section: Immersion Depthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

Ghaly¹

2011

American Journal of Applied Sciences

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“…Considering the overall efficiency across the tested salinities, IMA had higher SAE (1.82 kg O 2 /kW hr) followed by PWA (1.27 kg O 2 /kW hr), AJA (1.17 kg O 2 /kW hr), SLA (0.996) and SUB (0.341 kg O 2 /kW hr). Studies have indicated that SAE values of PWA efficiency ranged from 1.1 to 3.0 kg O 2 /kW hr (Ahmad & Boyd, ; Kumar et al, ) will vary significantly as it is generally fabricated by farmers or the local machine shop operators (Moulick, Mal, & Bandyopadhyay, ). Roy et al () observed that spiral aerators had maximum SAE of 1 kg O 2 /kW hr.…”

Section: Discussionmentioning

confidence: 99%

Assessment of the new generation aeration systems efficiency and water current flow rate, its relation to the cost economics at varying salinities for Penaeus vannamei culture

et al. 2020

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The selection of aerators and correct numbers can play an essential role in reducing the cost of production in aquaculture. The new generation aerators, namely spiral leaf, air‐jet, submersible and impeller, used in aquaculture, were assessed for its aeration efficiency and energy cost compared with the commonly used paddle wheel aerator. Of the aerators tested, the impeller had the highest aeration efficiency of 2.098 kg O2/kW hr, followed by paddle wheel with 1.436 kg O2/kW hr at 20‰ salinity. The spiral and air‐jet aerators had maximum aeration efficiency of 1.326 and 1.419 kg O2/kW hr, respectively, at 35‰ salinity. The submersible aerator was not efficient as its maximum efficiency was 0.380 kg O2/kW hr. The water flow by paddle wheel was 3 ft/sec and also provides better coverage than other types of aerators. The efficiency of aerators was high in optimum salinities (20‰ and 35‰) than the low or high saline condition. The average energy cost of shrimp pond aeration per hectare was lowest for impeller, followed by paddle wheel aerator. The study provided economic comparisons of vannamei culture using different aeration systems by keeping a uniform set of economic assumptions. Shrimp farms with impellors can give 14%–25% high returns across salinities, whereas spiral leaf can provide 5% high returns at 35‰ salinity. The combination of the type of aerators and the calculated use based on the salinity of the culture systems can result in energy‐saving and also a reduction in the production cost.

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“…A wide variation in performance of aerators in terms of standard aeration efficiency was found, like, Taiwanese aerator (1.17 kg 0 2 /kWh), Japanese aerator (1.03 kg 0 2 /kWh) and Auburn university design (2.25 kg 0 2 /kWh) (Busch et al 1974;Boyd and Watten 1989;Boyd, 1998;Colt, 2000a;2000b). Ahmad and Boyd (1988) provided optimum designs of paddle wheels and Moulick et al (2002) used similarity criteria in predicting the oxygen transfer performance of paddle wheel aerators. The centrifugal surface aerator along with the paddle wheel surface aerator had been traditionally used in wastewater treatment (Stukenberg et al, 1977;ASCE, 1997).…”

Section: Introductionmentioning

confidence: 99%

Oxidation ditch process using curved blade rotor as aerator

Thakre

Bhuyar

Deshmukh

2008

Int. J. Environ. Sci. Technol.

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S. B. Thakre et al. AB STRACT:Oxidation ditch process is used to treat the municipal and domestic sewage. The untreated sewage generates fouling smell, harmful bacteria, etc. which is hazardous for public health and degrades the environment by librating noxious gases. This paper examines the use of curved blade aerator for oxidation ditch process. The rotor, which controls the aeration, is the main component of the aeration process. Therefore, the objective of this study is to find out the variations in overall oxygen transfer coefficient and aeration efficiency for different configurations of aerators by varying the parameters like speed of aerator, depth of immersion and blade tip angles so as to yield higher values of overall oxygen transfer coefficient and aeration efficiency. Four aerators of different configuration were developed and fabricated in the laboratory and were tested for above mentioned parameters. A mathematical model is developed for predicting the values of k L a and aeration efficiency which has R 2 values of 0.97 and 0.99 for experimentally determined and calculated values. In laboratory studies, the optimum value of overall oxygen transfer coefficient and aeration efficiency were observed to be 10.33/h and 2.269 kg O 2 /kWh for aerator speed of 48 rpm, 5.5 cm depth of immersion and 47 o blade tip angle for curved blade aerator.

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Prediction of aeration performance of paddle wheel aerators

Cited by 44 publications

References 9 publications

Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

Assessment of the new generation aeration systems efficiency and water current flow rate, its relation to the cost economics at varying salinities for Penaeus vannamei culture

Oxidation ditch process using curved blade rotor as aerator

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