Separation characteristics in dissolved air flotation - pilot and full-scale demonstration

Ljunggren, Michael; Jönsson, Lennart

doi:10.2166/wst.2003.0169

Cited by 3 publications

(1 citation statement)

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“…Air fl otation combined with chemical coagulation techniques are commonly employed in the solid/water separation process when the specifi c gravity of suspended particles is lower or close to that of water (Arora et al 1995;Edzwald 1995;Fukushi et al 1995;Vlaski et al 1997;Voronin and Dibrov 1998;Haarhoff and Edzwald 2001;Han et al 2001;Al-Shamrani et al 2002;Rubio et al 2002;Ljunggren and Jonsson 2003). However, these processes have several disadvantages on process water treatment in automotive assembly paint booths: (1) chemical preparation, device operation and maintenance, as well as chemical transportation and storage are costly and time consuming; (2) the type of chemical and its dosage need to be closely monitored and routinely tested to ensure system performance, which further increases operation costs and affects treatment effi ciency; (3) chemicals added in the process water of paint booths are nonrecoverable and increase the mass and volume of paint sludge generated in the process, and as a result, lead to increased cost of sludge dewatering and disposal as well as diffi culties in sludge recycling and reuse; (4) many of the chemicals used in the process are water-soluble organic solvents and will remain in the process water, and, as a result, have impacts when the process water is discharged, particularly when there is a strict limit to the amount of organic matter discharged (Kia et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic Flotation of Process Water from Paint Booths

Shang

Yono

et al. 2009

Water Quality Research Journal

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Electrokinetic flotation (EKF) for separation of paint solids and process water from automotive assembly paint booths was investigated in a series of laboratory-scale batch experiments. The EKF process employs a single electrode-module and a DC (direct current) power supply, but does not use any chemical agents or air supplier. The electrode-module, which consists of parallel electrode plates, was developed and used in the experiments. The influencing parameters of the EKF process for the process water treatment, including the type of paint, initial suspended paint solids (SS) concentration, and applied electric current, were investigated in the experimental program. It was found from this study that the EKF process decreased the SS concentration from 300 to 100 mg/L in 30 minutes at 55 A/m2 in the water-borne paint water, from 150 to 50 mg/L in 5 minutes at 22 A/m2 in the solvent-borne paint water, and from 550 to 100 mg/L in 5 minutes at 44 A/m2 in the mixed paint water, as well as reduced colour and chemical oxygen demand (COD). The study concluded that paint type, initial SS concentration, and electric current are the most important parameters in the EKF process governing the effectiveness of solid/water separation, treatment time, and power consumption. A comparison of SS removal between the chemical coagulation and the EKF treatments showed that SS removal by the EKF process was similar to the chemical treatment. The study concluded that the EKF is an effective technique for solid/water separation in paint booths with simultaneous COD and colour removal.

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Section: Introductionmentioning

confidence: 99%

Electrokinetic Flotation of Process Water from Paint Booths

Shang

Yono

et al. 2009

Water Quality Research Journal

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Purification of white waters by selective flotation

Haapala

Körkkö

Kemppainen

et al. 2010

BioRes

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Removal of detrimental contaminants from paper machine circulation waters is known to benefit process runnability and paper quality. The applicability of selective flotation to remove substances of a hydrophobic nature from paper machine circulation waters was investigated in laboratory-scale experiments. The separation efficiency of ink, stickies, and wood extractives was studied by using a flotation scheme in which the froth was generated by the white water’s inherent surface active components without any chemical addition. The removal efficiency of detrimental contaminants was considered in relation to total losses of solid materials. The results showed that while not all white waters were able to produce stabile froth, those that generated froth also exhibited substantial separation of contaminants in the froth. With a moderate removal of 10% of total solids from white waters, removal of 45% of stickies, 27% of ink, and 20 to 50% of wood extractives was observed. Higher removal of contaminants resulted in solids losses at levels that are not economically feasible in paper production. The results showed that selective white water flotation can have beneficial results for papermaking processes.

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Biofilter Treatment of Waste Air Containing Malodor and VOC: 1. Pressure Drop and Microbe-population Distribution of Biofilter with Improved Design

Lee¹,

Lim²

2013

Korean Chemical Engineering Research

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Abstact − In this study, both pressure drop and microbe-population-distribution were observed while running a novel biofilter system with improved design in which the biofilter system is composed of two, upper and lower biofilters with both equal feed-rates of up-flow and down-flow, respectively. Then they were compared with the pressure drop and microbe-population-distribution observed in a conventional biofilter of the same effective volume with unidirectional flow. The pressure drop-value of biofilter system with improved design turned out to be less at the incipient stage of run or steady-state long term operation by more than 40~80% of that of the conventional biofilter. The microbe-populationdistribution was observed to be lower and higher at higher and lower column of biofilter, respectively, for both the conventional biofilter and the biofilter system with improved design. The microbe-media of waste-tire crumb showed much greater CFU counts than GAC. In the biofilter system with improved design, the bottom→up feeding of waste air showed greater microbe-population growth than the top→down feeding for both the microbe-media of waste-tire crumb and GAC. However, it was more prominent for the former than the latter. Comparing the microbe-population-distributions of both of the conventional biofilter and the biofilter system with improved design, the microbe-population of latter was distributed ca. 15 and 2.5 times more evenly for GAC and the media of waste-tire crumb, respectively, than that of former.

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Separation characteristics in dissolved air flotation - pilot and full-scale demonstration

Cited by 3 publications

References 0 publications

Electrokinetic Flotation of Process Water from Paint Booths

Electrokinetic Flotation of Process Water from Paint Booths

Purification of white waters by selective flotation

Biofilter Treatment of Waste Air Containing Malodor and VOC: 1. Pressure Drop and Microbe-population Distribution of Biofilter with Improved Design

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