• Journal of the Mineralogical Society of Korea
• /
• v.23 no.1
• /
• pp.85-91
• /
• 2010

The various forms of heavy metals in soil environments have been studied by sequential extraction method. We tested conventional Tessier sequential extraction and new ultrasound-sonication extraction methods, and compared their extraction efficiency. Total As, Cd, Cu, Pb, and Zn contents of the target soil (NIST SRM 2710 Montana Soil), by three methods (USEPA Method 3050B, KBSI Method, and ultrasound-sonication method) were all consistent with the certified values. Sequential extraction efficiency along with step-wise extraction values was similar in both Tessier method and ultrasound-sonication method. The ultrasound-sonication method took about 3 hours to complete whole procedure while the Tessier sequential extraction method took around 12 hours. Ultrasound-sonication method was estimated as one of the best methods with a relatively short application time and no requirement of high temperature treatment.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.647-654
• /
• 2003

This study investigated the effect of ultrasound on the permeability of the filter paper The investigation involves laboratory experiments, and the laboratory tests were conducted under abroad range of conditions Including energy levels of ultrasonic waves, time for treatment, and temperature. The results of the study show that sonication enhances the permeability of the filter paper significantly. The degree of enhancement varies with sonication power and duration of application. The effect of sonication on permeability with temperature variation and concentration of the test specimens seems not to be significant.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.613-620
• /
• 2003

This study investigated the effect of ultrasound on the permeability of the granular soil. The investigation laboratory experiments, and laboratory tests were conducted under a broad range of conditions including energy levels of ultrasonic waves, time for the treatment, and type of the soil. The results of the study show that sonication enhances the permeability of the soil specimens significantly. The degree of varies with sonication power and duration of application, and type of soil.

• Proceedings of the KSEEG Conference
• /
• 2007.04a
• /
• pp.407-411
• /
• 2007

See Full Text

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.6
• /
• pp.893-906
• /
• 2011

The effect of ultrasound pretreatment on sludge degragability was investigated at different condotions: ultrasonic frequency(28, 40, 50kHz), intensity(10, 25, 50W), sonication time(10, 20, 30, 60min). Total suspended solid(TSS) and soluble chemical oxygen demand(SCOD) concentration were measured for the evaluation of pretreatment efficiency. The pretreated sludge was used as the feedstock for anaerobic digestion process. Biogas production and volatile suspended solid(VSS) removal were determined for evaluating the process performance. 1. TSS concentration of the sludge decreased at a constant rate as sonication operation was applied. The degradation rate of TSS increased when ultrasound frequency was decreased from 50kHz to 28kHz and intensity was increased from 10W to 50W. Efficiency of TSS degradation per input energy increased as ultrasonic frequency and intensity were decreased. At the frequency of 28 and 40kHz, SCOD concentration rapidly increased during the initial 30min of sonication time, and then it gradually increased. At 50kHz, SCOD concentration constantly increased for 60min of the sonication time. The SCOD production rate increased with increasing intensity under all ultrasound frequencies. 2. The optimum condition of ultrasound treatment was 28kHz, 50W and 60min for maximizing the biogas production, methane fraction, VSS removal. The highest values in biogas production, methane fraction in biogas, VSS removal were 370ml, 70%, 2.45g, respectively. Methane production rate per input energy increased at ultrasonic frequency and intensity decreased. 3. When raw sludge was pretreated at the condition of ultrasonic frequency of 28 and 40kHz in series, sequential-frequency sonication, intensity of 50W and 60min, biogas production, methane fraction, VSS removal were about the same that of 28kHz single-frequency sonication. When sequential-frequency sonication of 28 and 50kHz was applied in series, biogas production, methane fraction, VSS removal were 356 ~ 423ml, 69 ~ 71%, 2.41 ~ 2.78g, respectively. The pretreatment efficiency of 28-50kHz sequential-frequency sonication which sonication time of 28kHz and 50kHz was 40min and 20min was higher than that of 28kHz single-frequency sonication.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.313-320
• /
• 2002

In accordance with the need of developing a methodology for the sludge reduction, this study investigates the effect of sonication on the dewaterability of the sewage sludge. The investigation involves laboratory experiments of the sewage sludge from Yongin Waste Treatment Plant. The Laboratory tests were conducted under a broad range of conditions including energy levels of ultrasonic waves, time for the treatment, pH, and effect of polymers. The results of the study show that sonication enhances the dewaterability significantly The degree of enhancement varies with sonication power, treatment time, the amount of sludge treated. The effect of sonication on the temperature and pH of the test specimens seems not to be significant. The polymer can be useful to enhance the effectiveness of ultrasound treatment.

• Journal of the Korean Society of Radiology
• /
• v.9 no.7
• /
• pp.523-528
• /
• 2015

In this study, we evaluated the heating characteristics of single sonication and superposed two low-intensity ultrasonic sonication. Compare the results, the superposed sonication was showed a superior thermal effect than single sonication. And the maximum temperature was increased as 120-150%. The starting time of temperature rising has been shortened in superposed sonication. In addition, the time up to the maximum temperature has been shortened, too. In generally, as the ultrasonic intensity is higher, the more surface damage is occurred. However, in the case of superposed sonication, the same thermal effect had be confirmed without surface damage. Through the results of the study, we thought that the superposed sonication will be able to reduce the intensity of the ultrasonic treatment. And, by using the low-intensity, the more safe and more effect therapy will be possible in therapeutic ultrasound application.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.401-406
• /
• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.

• Journal of Environmental Science International
• /
• v.13 no.2
• /
• pp.167-173
• /
• 2004

A aqueous solution of malodorants (i.e., n-valeraldehyde, n-valeric- acid, 2-methylisoborneol, and trimethylamine) was exposed to 200KHz ultrasound with a power of 6.0W/$\textrm{cm}^2$ per unit volume in a sonochemical reactor under room temperature and atmospheric pressure condition. The concentration of malodorants decreased with irradiation time, indicating pseudo-first-order kinetics. The removal efficiency of malodorants was about from 50% to 96% decomposed after 90 minutes sonication. At the deodorization, it was determined by triangle odor bag(TOB) method for odor sensory measurement, and it indicated that over 60% of relative odors were deodorized with degradation by the sonication.

• International journal of advanced smart convergence
• /
• v.5 no.2
• /
• pp.18-23
• /
• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.