• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.237-245
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• 2017

This study was aimed at investigating effluent water quality and proposing reuse possibilities for 12 sewage treatment plants discharged more than $5,000m^3/day$ in order to recycle the sewage treatment plant effluent of Jeollabuk-do effectively. Additionally, a laboratory scale test for reprocessing water discharge was performed. Categories of reclaimed sewage water reuse were divided into 7 topics and analyzed a total of 28 items including 16 heavy metals based on water quality standard. As a results, color, BOD, TN, chloride and Electrical Conductivity (EC) exceeded reused water quality standard. In particular, color and TN exceeded in 8 and 5 sewage treatment plants, respectively. The value of chloride and EC were high in sewage treatment plants including the food and industrial wastewater. At 4 sewage treatment plants were possible to reuse without re-treatment. The laboratory scale test was conducted to SandFilter (SF)-Granular Activated Carbon (GAC)-MicroFiltraion (MF)-Reverse Osmosis (RO). Both the removal efficiencies and economic feasibility of total E. coli., color and Suspended Solid (SS) suited in case using the SF-GAC treatment method. The removal of chloride and EC had little effect in the case of SF-GAC-MF system, but RO showed over 90% of removal efficiency. After using SF-GAC process only, the concentration of $UV_{254}$ decreased sharply from 0.3651 /cm to 0.0306 /cm and it showed over 92% of removal efficiency rate. In conclusion, for the effective reuse of sewage discharged water, water quality and the surrounding terrain of treatment plants should be all taken into account. If it needed for the reprocessing, both the selection for treatment and economic combination treatment methods will have to be considered.

• Korean Journal of Materials Research
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• v.14 no.3
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• pp.229-234
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• 2004

All the applications of natural zeolites make use of one or more of their physical and chemical properties: adsorption, ion-exchange and related molecular sieve properties, dehydration and rehydration, and siliceous composition. Accordingly, the applications of zeolite have been carried out in the various aspects because of its large cation exchange capacity and adsorption properties. In this paper, the adsorption effect of heavy metal ions in wastewater on zeolite mineral by batch adsorption process is studied. The amounts of adsorbed ions were variable by original pH and ionic concentration, especially original pH of solution had an important effect on the adsorption. In case of low pH solution, e.g. below 3.0, clinoptilolite adsorbed $Pb^{2+}$ ,$ Cd ^{2+ }$ , $Cu^{2+}$ and $Zn^{ 2+}$ , but mordenite almost did not adsorb except $Pb^{2+}$ . Under the same conditions, these ions were more adsorbed on clinoptilolite than on mordenite mineral. The velocity of adsorption was relatively fast and it was confirmed by shaking test that the equilibrium of adsorption could be attained in about one hour. The species of exchangeable cation of zeolite had an effect on its removing ability and zeolite of the sodium-exchanged type was the best.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.13-21
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• 2000

Detention basin is the temporary holding pond of treated water prior to flow out to the sea. It is very common to dredge the soil from the bottom of detention basin to keep up the water holding capacity. In this study, the amount of volume reduction of dredged soil from detention basin was estimated based on the laboratory test results. The percentage of soil particles in dredged organic soil is about 12.5∼21.9% by weight. The content of heavy metal and environmental effect for dredged soil itself and solidified dredged soil were analysed and the results are meet the standards of environmental requirement.

• Journal of Environmental Science International
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• v.15 no.3
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• pp.279-286
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• 2006

Electrokinetic technique was considered in removing arsenic from the abandoned mining tails. In order to estimate the removal characteristics of arsenic, the sequential extraction analysis and desorption experiment were carried out prior to the application of electrokientic process. The result of sequential extraction analysis indicated that the water soluble and exchangeable fraction, easily leachable to ground water, were very low as much as about 2.5% and the fraction except residual (38.3%), possibly extractable under very acidic or alkalic environment, was about 59%. In the result of desorption test using four different kinds of electrolytes, the mixture of citric acid and sodium dodecyl sulfate (SDS) showed the highest desorption efficiency as much as 77.3%. The removal efficiencies of arsenic from mining tailings by electrokinetic process under the different electrolyte environments were slightly low and resulted in the following order: citric acid + SDS (18.6%) > 0.1 $NHNO_3$ (8.1%) > HAc (7.4%) > Distilled water(6.6%). Also, arsenic in soil matrix was moved favorably in the direction of anodic rather than cathodic region, which is opposite trend with cationic metal ions generally existing in soil, because anionic form of arsenic is dominated in acidic soil caused by the movement of acid front form anode.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.393-397
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• 1999

Among various reactions which metal sulfides can undergo in the reducing environment, the lattice exchange reaction was examined in a attempt to selectively remove heavy metal ions contained in the Fe-Coagulants acid solution. We have examined Zeta potential along with pHs to investigate surface characteristics of ${FeS}_{(s)}$. As a result of this experiment, zero point charge(ZPC) of FeS is pH 7 and zeta potential which resulted from solid solution reaction between Pb(II) and ${FeS}_{(s)}$ is similar to that of ${PbS}_{(s)}$. Solubility characteristics of ${FeS}_{(s)}$ is appeared to that dissolved Fe(II) concentration increased in less than pH 4, and also increased with increasing heavy metal concentration. Various heavy metal ions(Pb(II), Cu(II), Zn(II)) contained in Fe-coagulants acid solution were removed selectively more than ninety-five percent in the rang of pH 2.5~10 by ${FeS}_{(s)}$. From the above experiments, therefore, We could know that the products of reaction between heavy metal ions and $FeS_{(S)}$ are mental sulfide such as $PbS_{(S)}$, $CuS_{(S)}$ and $ZnS_{(S)}$.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1303-1308
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• 2003

This experiment was carried out to investigate the effects of heavy metals (cadmium, chromium, copper and lead) on the seed germination of Arabidopsis thaliana, and examinated the removal effects of biostone and green tea on the heavy metal toxicity. Cadmium and chromium among the four heavy metals had no effect on the seed germination even in the concentration fifty times higher than in the official standard concentration of pollutant exhaust notified by the Ministry of Environment. However, seeds were not germinated in the concentration of copper ten times higher and in the concentration of lead fifty times higher than the official standard concentration. When seeds were sown in the solutions of lead (15, 20, 25 and 30 mg/L) and copper(15 and 20 mg/L), the seed germination rates were 0％ and less than 10％, respectively. However, when biostone(3 g/30 $m\ell$) was added, the seed germination rate was 100％ in all the concentrations. The germination rate was 100％ in distilled water and copper solution (5 mg/L). However, green tea (0.2 g/30 $m\ell$) was added, the seed germination rate was 0％ in both. The results show that cadmiun and chromium had no effect on the seed germination, but lead and copper decreased the rate of seed germination of Arabidopsis thaliana, Biostone removed heavy metal toxicity, but green tea did not removed heavy metal toxicity during germination.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.57-67
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• 2012

The midge samples were undertaken at three streams, representing different surrounding environments, to investigate the contaminant exposure of midge. The content of heavy metals in midge collected in Singil stream were generally higher as a result of input to the industrial effluents with respect to other streams. Adsorption experiments were done to evaluate the possibility of removing contaminants from water with midge. Diazinon and heavy metals were contaminant target compounds in this study. The removal rate of diazinon in water by midge was 60-75%. In the case of Cu, the removal rate was reached around 90% at the lower initial concentration of 1.87 and 0.81 ppm rather than 4.25 ppm. The reduction of concentration of Cr and Cd according to the lapse of time was similar to the Cu, but their removal rates were shown 50% and 60-74%, respectively. The removal rate of Zn by midge represented relatively high level within the experimental condition. No change in concentration of Cr and As with time were occurred at all experimental conditions. It accounts for the fact that the reduction of Cr and As could not be achieved through the adsorption process, using midge.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.58-64
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• 2013

This study proposed a low temperature hydrothermal carbonization to treat and recycle sewage sludge and determined the optimal conditions for the biochar production. The physical and chemical properties of biochar were analyzed and its sorption capacity for heavy metals was evaluated. To produce biochar, 50 g of sewage sludge was heated at 220, 230, and $240^{\circ}C$ for 1, 2, 3, 5, 8, and 10 hours in a reactor. The optimal conditions to produce biochar was $230^{\circ}C$ and 8 hours. Sorption capacity tests were conducted for arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni). Among them, lead was shown the highest heavy metal adsorption efficiency of biochar, followed by copper, cadmium, zinc, and nickel, but arsenic was hardly adsorbed overall.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.3
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• pp.253-259
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• 2018

Cu(II) can cause health problem for human being and phosphate is a key pollutant induces eutrophication in rivers and ponds. To remove of Cu(II) and phosphate from solution, chitosan as adsorbent was chosen and used as a form of hydrogel bead. Due to the chemical instability of hydrogel chitosan bead (HCB), the crosslinked HCB by glutaraldehyde (GA) was prepared (HCB-G). HCB-G maintained the spherical bead type at 1% HCl without a loss of chitosan. A variety of batch experiment tests were carried out to determine the removal efficiency (%), maximum uptake (Q, mg/g), and reaction rate. In the single presence of Cu(II) or phosphate, the removal efficiency was obtained to 17 and 16%, respectively. However, the removal efficiency of Cu(II) and phosphate was increased to 50~55% at a mixed solution. The maximum uptake (Q) for Cu(II) and phosphate was enhanced from 11.3 to74.4 mg/g and from 3.34 to 36.6 mg/g, respectively. While the reaction rate of Cu(II) and phosphate was almost finished within 24 and 6 h at single solution, it was not changed for Cu(II) but was retarded for phosphate at mixed solution.