Ultrasonic technology is a promising tool for washing oily sludge to recover oil. In this study, the influence of ultrasonic conditions on the removal of different oil components from oily sludge was investigated to optimize ultrasonic washing technology. Among the three frequencies (25, 50 and 100 kHz) applied, ultrasonic washing at 25 kHz exhibited the best performance in terms of oil extraction rate and efficiency. An ultrasonic intensity of 0.33 W/cm2 was necessary to overcome the energy threshold for oil washing. Application of a standing wave or dual frequencies did not improve the oil removal performance perceptibly. The optimum conditions for the removal of oil from oily sludge were an ultrasonic frequency of 25 kHz, intensity of 0.33 W/cm2 and sludge/water ratio of 1/2 (in volume). Thin-layer chromatographic flame ionization detection showed that ultrasonication could overcome high energy thresholds, resulting in an increase in the removal of asphaltenes and resins, with the removal of asphaltenes particularly affected by frequency. This study could provide valuable information for the application of ultrasonic technology in oily sludge treatment.
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http://dx.doi.org/10.1080/09593330.2015.1010594 | DOI Listing |
Toxics
December 2024
School of Resource and Environmental Engineering, Shandong University of Technology, Zibo 255000, China.
The solid phase composition in oily sludge (OS) is a key factor affecting the oil-solid separation of OS. In this paper, the effects and mechanisms of solid-phase particle factors on the oil content of residue phase were investigated in order to improve the oil-solid separation efficiency. Flotation experiments were carried out on single-size sand and mixed-size sand OS consisting of three particle sizes at room temperature without adding flotation reagents.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Resources Engineering, National Cheng Kung University, Tainan 701, Taiwan.
In the waste oil recycling industry, large amounts of oil-containing sludge are still generated, thus posing a resource depletion issue when disposed of or incinerated without energy recovery or residual oil utilization. In this work, chemical activation experiments using phosphoric acid (HPO) were performed at a low temperature (600 °C) for 30 min to produce porous carbon products. From the results of the pore property analysis, an increasing trend with an increasing impregnation ratio from 0.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Department of Environmental Engineering, Gebze Technical University, Kocaeli, 41400, Turkey.
The improper disposal of olive mill wastewater (OMW) presents a significant environmental challenge for wastewater treatment plants (WWTPs) in the Gaza Strip. This study aims to evaluate the impact of OMW discharge on the operational efficiency of WWTPs, particularly during the olive harvesting season. To achieve this, samples were collected from both olive mills and WWTPs across the region and analyzed for key parameters such as chemical oxygen demand (COD), biological oxygen demand (BOD), phenols, oil and grease, and total suspended solids (TSS).
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, China.
Bioresour Technol
December 2024
Department of Environmental Engineering, College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China. Electronic address:
The presence of petroleum hydrocarbon components (PHCs) in biological oily sludge increases the toxicity of the sludge and makes dewatering even more difficult. In this study, an atmospheric pressure plasma jet (APPJ) technology was used for treating biological oily sludge. The results showed that under specific conditions-a sludge/water ratio of 1:100, a discharge power of 440 W, and a 60-min treatment-the degradation rate of PHCs reached 36.
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