Separation of oil from oily sludge by freezing and thawing

Jean, D.S; Lee, D.J; Wu, Jeffrey C.S.

doi:10.1016/s0043-1354(99)00005-6

Cited by 68 publications

(30 citation statements)

References 7 publications

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“…<25 mg/L). This was in agreement w ith previous studies that F/T m ethod was effective for separating oil from the aqueous phase (Chen and He, 2003;Jean et al, 1999). As described above, the com bined process brought higher oil recovery than that for the ultrasonic treatment alone, and much higher TPH concentration in the recovered oil layer than that for the F/T method.…”

Section: Com Parison O F Methodssupporting

confidence: 93%

“…61%). The observed sludge settleability after freeze/thaw treatment in this study w as not in agreement w ith previous study conducted by Jean et al (1999) who used freeze/thaw to treat the oily sludge samples taken from the dissolved air flotation (DAF) unit o f a w astew ater treatment plant. The crude oil tank bottom sludge used in this study contained more solid content (i.e.…”

Section: Com Parison O F Methodscontrasting

confidence: 77%

“…Freeze/thaw (F/T) used for sewage sludge dew atering in cold regions has been reported as one effective and feasible method for dem ulsification in recent years (Jean et al, 1999;Chen and He, 2003;Rajakovic and Skala, 2006). For example, Lin and He (2007) The objective o f this study is then to evaluate the oil recovery efficiency o f the com bined ultrasonic and freeze/thaw approach for oily sludge treatment, and several factors including ultrasonic power, ultrasonic treatment duration, addition o f bio-surfactant, addition o f salt as well as sludge to w ater ratio were investigated for their effects on the treatm ent performance.…”

Section: Introductionmentioning

confidence: 99%

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Treatment of refinery oily sludge using ultrasound, bio-surfactant, and advanced oxidation processes.

Zhang¹

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Section: Com Parison O F Methodssupporting

confidence: 93%

Section: Com Parison O F Methodscontrasting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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Treatment of refinery oily sludge using ultrasound, bio-surfactant, and advanced oxidation processes.

Zhang¹

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“…10,11 Using freezing and thawing as pretreatment, a more than 50% release of oil from sludge has been achieved, improving also its fi lterability. 12 The optimal freezing temperature was found to be −40°C with suffi cient freezing time; 13 the best thawing conditions were below +20°C. 10 Ultrafast freezing did not improve oil separation.…”

Section: Introductionmentioning

confidence: 96%

Characterization of oily sludge from a wastewater treatment plant flocculation-flotation unit in a petroleum refinery and its treatment implications

Kriipsalu

Marques

Maastik

2008

J Mater Cycles Waste Manag

106

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Partly due to the complex and variable composition of oily sludge generated by the petroleum industry, cost-effective treatment and proper disposal pose considerable challenges worldwide. In this study, an extended component-based analysis of the oily sludge from a fl occulation-fl otation unit of a wastewater treatment system in a refi nery in Sweden was carried out over 1 year. The heterogeneity of the oily sludge is illustrated by the wide ranges of concentrations found for different chemical components, particularly metals. Among the petroleum hydrocarbons, the most abundant compounds were nonpolar aliphatic hydrocarbons (63.7 ± 16.7 g kg −1 ); from the benzene, toluene, ethylbenzene, and xylene group, xylenes (91-240 mg kg −1 ) were most abundant; and among polycyclic aromatic hydrocarbons, naphthalene (25.7 ± 21.4), fl uorene (27.25 ± 10.0), and phenanthrene (43.8 ± 18.4 mg kg −1 ) were most abundant (all results in terms of dry matter). Based on the EU guidelines and the mean concentration values for metals found in the oily sludge, e.g., Pb (135.4 ± 125.8), Cu (105.2 ± 79.1), Hg (42.8 ± 31.3), Ni (320 ± 267.4), and Zn (1321.7 ± 529.9 mg kg −1 ), disposal of oily sludge even in landfi lls for hazardous waste is not allowed. The organic content of the sludge can be reduced through biotreatment, but not the metal content. A multistep component-based treatment scheme is therefore needed.The oily sludge generated at fl occulation-fl otation units (FFU sludge) of wastewater treatment plants contains J Mater Cycles Waste Manag (2008) 10:79-86

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“…Previous studies have reported that freeze/thaw processing can significantly improve certain sludge dewatering characteristics [8][9][10]. This physical approach can irreversibly change the floc's structure into a more compact form, thereby reducing the interstitial water content of sludge.…”

Section: Introductionmentioning

confidence: 99%

Improvement of acidification on dewaterability of oily sludge from flotation

Guo

et al. 2011

Chemical Engineering Journal

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a b s t r a c tThis paper presents the improvement of acidification on the dewaterability of oily sludge from a flotation process. Various parameters, including the volume of supernatant water, capillary suction time (CST), and specific resistance to filtration (SRF) were used to evaluate the dewaterability of oily sludge. In addition, floc size distribution and release rates of Al(III) were used to explain skeleton breakage as a result of the acidification treatment. Results show that dewaterability increased obviously as the sludge pH decreased. After 120 min of settling, the volume of supernatant water reached 77% at pH 4.0. Maximum reductions in CST and SRF were 93.1% and 89.2%, respectively. Following acidification, the flocs in the oily sludge achieved a broader particle size distribution and a smaller median diameter [d (0.5)] of 36.0 m (cf. 74.4 m for the raw sample). In addition, lower pH led to a greater rate of release of Al(III). This study verifies that the floc skeleton of oily sludge can be broken through the dissolution of aluminum hydroxide; i.e., acidification enhances the dewaterability of oily sludge by changing the floc structure. All results indicate that acidification is advisable as a pretreatment of oily sludge.

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Separation of oil from oily sludge by freezing and thawing

Cited by 68 publications

References 7 publications

Treatment of refinery oily sludge using ultrasound, bio-surfactant, and advanced oxidation processes.

Treatment of refinery oily sludge using ultrasound, bio-surfactant, and advanced oxidation processes.

Characterization of oily sludge from a wastewater treatment plant flocculation-flotation unit in a petroleum refinery and its treatment implications

Improvement of acidification on dewaterability of oily sludge from flotation

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