• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.1
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• pp.169-177
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• 2006

In this study, it was studied that the removal rate of VOC by the catalytic combustion. The combustion temperature was changed by the contact type of VOC(space velocity and catalyst depth) and the space velocity(SV) was defined by the rate of gas volume flow rate(Q, $m^3/hr$) over volume(V, $m^3$) of catalyst (SV=Q/V). The space velocity of catalytic combustor is maintained $10,000{\sim}50,000hr^{-1}$. it was studied that the conversion rate of VOC by the catalytic combustion. The combustion temperature was changed by the contact type of VOC and catalyst and the space velocity was defined by the rate of gas volume flow rate over volume of catalyst. The VOC which pass thru the heat exchanger was measured by the hydro ionic detector and measured the VOC removal rate by the activated catalyst in the reaction temperature range of 373K-423K. The removal rate was measured over 100 times. In the automobile painting booth The VOC concentration was 63.37ppm and the removal rate was 70 % at 373K and 78.92% at 423K. The removal rate was increased as increased the temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.556-563
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• 2016

We examined the removal of hazardous heavy metals (Cd, Cr, and Pb) from laver Pyropia sp. using citric, hydrochloric, and nitric acids. Under the same conditions, the quality of the laver samples was also evaluated using the variation in absorbance and major mineral levels. The heavy metals that accumulated in raw laver samples after 3 days in seawater included Pb (117.79 μg/g), Cr (33.53 μg/g), and Cd (10.54 μg/g) in descending order. The rate of heavy metal removal from laver was higher at lower pH for all acids used. However, its color changed unsatisfactorily at pH 2.0. After 10 min in seawater at pH 2.5, the heavy metals in laver were eliminated in the order Cd (68.7–81.6%), Pb (57.7–67.0%), and Cr (31.9–49.4%) using the three acids. The differences in heavy metal removal among acid types were not significant. The laver quality was not affected after 20 min at the pH range of 2.5–4.0. The maximum removal of heavy metals was from laver soaked for 10 min in seawater at pH 2.5 using the organic acid, citric acid.

• Analytical Science and Technology
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• v.13 no.2
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• pp.234-240
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• 2000

The efficiency of Photocatalytic Oxidation Process were investigated for the treatment of Aquatic Humic Substances (AHS). In UV-only system, pH 7-9 was the optimum pH range for TOC removal, and alkali range was the optimum pH for absorbance decrease. In UV/$TiO_2$ system, the optimum $TiO_2$ dosage was 50ppm and over 50ppm of $TiO_2$ dosage was not effective for removal of AHS. In UV/$H_2O_2$ system, optimum $H_2O_2$ dosage was 20mM, when over 20mM dosage, removal of TOC (Total Organic Carbon) and absorbance was decreased. Radical scavenger affected on the photo-oxidation of AHS. Removal rate of TOC and absorbance was decreased by addition of carbonate ions and TOC removal was more effected than that of absorbance.

• Journal of Environmental Health Sciences
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• v.34 no.3
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• pp.233-239
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• 2008

In order to improve reactor performance of existing sewage treatment plants, the feasibility of enhancing reactor performance by bioaugmentation using EM as bioaugmentation agent and the effects of anoxic: oxic time ratio on reactor performance were investigated. Continuous and intermittent aeration modes were compared under the 6 hr of HRT. Three different types of intermittent aeration modes, that is, 15 min, of anoxic:45 min of oxic, 30 min of anoxic: 30 min of oxic, and 45 min of anoxic: 15 min oxic respectively were chosen as test modes to study the effects of anoxic : oxic time ratios on reactor performance. The optimum anoxic: oxic time ratio was 30 min:30 min when considering simultaneous removal of organic, nitrogen and phosphorus. When applying EM into a continuously aerated reactor under the varying dosing rates of 50-200 ppm, reactor performance in terms of organic and nitrogen removal efficiencies was not improved at all. Nitrogen removal efficiency was increase when the EM dosing rate was increased. However the degree of improvement was slight when the EM was injected above 100 ppm. However optimum phosphorus removal was found at the EM dosing of 200 ppm. Thus it was found that optimum injection concentration of EM is 200 ppm. It is apparent that putting EM into a sewage treatment plant significantly affects the T-N removal efficiency of the reactor by enhancing denitrification efficiency especially in operational conditions of relatively long anoxic periods. To achieve reciprocal condition in a reactor with intermittent aeration it is necessary to enhance the reactor performance by EM injection. In the case of modifying existing continuously aerated reactors into intermittent aerated reactors, it is obvious that operating costs of aeration would be reduced by reducing aeration time when compared with existing conventional sewage treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.5
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• pp.281-288
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• 2023

This study was performed to evaluate the pollutants removal characteristics of two types of RBFs(Riverbank filtration, Riverbed filtration) intake facilities installed in Nakdong River and in Hwang River respectively. The capacity of each RBF is 45,000 m³/d for riverbank filtration intake facility and 3,500 m³/d for riverbed filtration intake facility. According to data collected in the riverbank filtration site, removal rate of each pollutant was about BOD(Biochemical Oxygen Demand) 52%, TOC(Total Organic Carbon) 57%, SS(Suspended Solids) 44%, Total coliforms 99% correspondingly. Furthermore, Microcystins(-LR,-YR,-RR) were not found in riverbank filtered water compared to surface water in Nakdong River. DOC(Dissolved Organic Carbon) and Humics which are precursors of disinfection byproduct were also reported to be removed about 59% for DOC, 65% for Humics. Based on data analysis in riverbed filtration site in Hwang River, removal rate of each contaminant reaches to BOD 33.3%, TOC 38.5%, SS 38.9%, DOC 22.2%, UV254 21.2%, Total coliforms 73.8% respectively. Additionally, microplastics were also inspected that there was no obvious removal rate in riverbed filtered water compared to surface water in Hwang River.

• Clean Technology
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• v.30 no.3
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• pp.239-247
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• 2024

The removal of volatile organic compounds (VOCs) from spent polypropylene (PP) sourced from the bumpers and interiors of used cars was carried out by using high-temperature supercritical carbon dioxide (scCO₂) extraction. The recycled polymers from the bumpers and interiors contained other additives beside PP such as polyethylene (PE), talc, and carbon black, which modified the properties of PP. The crystallinity of the recycled bumper and interior PP was significantly lower than that of the virgin PP pellet. The decomposition temperatures of the recycled bumper and interior PP was slightly higher than that of the virgin PP pellet, while the melting and crystallization points were slightly lower. The effect of process conditions on VOC removal was studied by varying the time (2 ~ 720 min), pressure (6.4 ~ 14 MPa), and temperature (298 ~ 473 K). Since VOC removal at 2 min produced satisfying results, times below 2 min (10 ~ 120 s) were also studied. The main goal of scCO₂ extraction was to reduce the xylene content, as the xylene content of the recycled bumpers was higher than the allowable limit. A temperature above 373 K was needed to remove the xylene from the waste PP samples. The optimum condition for VOC removal from bumper waste was determined to be 433 K, 8 MPa, and 60 s. The car interior waste had VOC content within the allowable limit, so no further treatment was needed.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.38-46
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• 2008

Many researchers have reported that many biopolymers making up cell walls of the microorganisms display an ion-exchange property and play a major role in the sorption of the metal ions. Such polymers derived from microbial biomass are potentially useful as biosorbent materials for recovery various metal ions in industrial applications. although synthetic polymers such as ion-exchange resins and chelating resins have been widely used as commercial sorbents. In this study, valuable and commercial biopolymers for metal removal will be introduced.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.76-81
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• 2009

Thermal desorption systems are designed to remove organic compounds from solid matrices such as soils, sludges and filter cakes without thermally destroying them. It is a separation technology, not a destruction technology. Since it is a thermal process, there is a common belief that temperature is the only significant parameter to be monitored. While it is true that better removal efficiencies are usually achieved at higher temperatures, other factors must be considered. Since the process is governed by mass transfer, heating time and the amount of mixing are also key parameters in optimizing removal efficiency. Thermal desorption have been successfully used for just about every organic contaminant found to date. It has also been used to remove mercury. In the present study, the numerical simulation has been performed to investigate the characteristics of heat transfer of LTTD(low temperature thermal desorption). The commercial software, AMESIM was applied for analyzing the heat transfer process in the LTTD.

• Textile Coloration and Finishing
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• v.18 no.5 s.90
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• pp.48-52
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• 2006

A mixed adsorbent prepared by pyrolysing a mixture of carbon and flyash in 1:1 ratio was tested for its deceleration ability for three different classes of dyes, namely Astrazone Blue FRR(C.I. Basic Blue 69), Teflon Blue ANL(C.I. Acid Slue 125) and Verofix Red(Reactive Red 3GL). Equilibrium investigations were carried out at the optimum conditions obtained in the previous studies. The equilibrium data fitted reasonably well to both the Freundlich and Langmuir adsorption models. However the Langmuir model was more appropriate to describe the adsorption behavior of the dyes to the hybrid absorbent system compared with the Freundlich model. The mixed adsorbent cm be an low-cost alternative to activated carbons.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.205-209
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• 2003

The various pretreatment processes were evaluated for removal of oil pollutants with weathered oil contaminated seawater in a reverse osmosis desalination process. Weathered oil contaminated seawater was made by biodegradation and photooxidation with oil containing seawater. Coagulation, ultrafiltration, advanced oxidation processes and granular activated carbon filtration was used with pretreatment for dissolved organic carbon. Crude oil was removed but. weathered oil contaminated seawater was not removed by biodegradation and coagulation. DOC and E260 was removed with about 20 % and 40 % by membrane filter of cut off molecular weight 500. So, the most of dissolved organic carbon in weathered oil contaminated seawater was revealed that molecular weight was lower than 500. It is difficult to remove DOC in weathered oil contaminated seawater by advanced oxidation processes treatment, but, E260 was removed more high. However, DOC in weathered oil contaminated seawater was easily adsorbed to GAC. It is revealed that DOC was removed by adsorption.