• Membrane and Water Treatment
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• v.6 no.4
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• pp.339-349
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• 2015

Experiments were carried out using granular activated carbon (GAC) adsorption techniques to treat wastewater contaminated with organic compounds caused by diverse human activities. Two techniques were assessed: adsorbent GAC prepared from coconut shell (GACC) and adsorbent GAC from palm shell (GACP). A comparison of these two techniques was undertaken to identify ways to improve the efficiency of the treatment process. Analysis of the processed wastewater showed that with GACC the removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, total suspended solids (TSS) and total dissolved solids (TDS) was 65, 60, 82, 82 and 8.7%, respectively, while in the case of GACP, the removal efficiency was 55, 60, 81, 91 and 22%, respectively. It can therefore be concluded that GACC is more effective than GACP for BOD removal, while GACP is better than GACC for TSS and TDS removal. It was also found that for COD and turbidity almost the same results were achieved by the two techniques. In addition, it was observed that both GACC and GACP reduced pH value to 7.9 after 24 hrs. Moreover, the optimal time period for removal of BOD and TDS was 1 hr and 3 hrs, respectively, for both techniques.

• Membrane Journal
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• v.27 no.1
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• pp.77-83
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• 2017

Transient behavior of fouling resistance was observed with a laboratory-scaled, submerged microfiltration membrane system treating high-turbidity source water consisting of inorganic silica particles and humic acid. Fouling mitigation efficiency with inorganic silica particles caused by aeration was reduced significantly as both humic acid and calcium ion existed together. Scanning electron microscopic observations showed that humic acid was adsorbed onto the surface of inorganic silica particles in the presence of calcium. Turbidity removal was achieved almost completely by submerged MF system regardless of feed compositions. However, the $UV_{254}$ removal of humic acid was improved in the presence of both calcium and inorganic silica particles. Additionally, increasing air-flow rate tended to increase $UV_{254}$ removal efficiency higher than 80%. This may be caused by back-transport of humic acid enhanced by inorganic silica particles providing surface for organic adsorption in the presence of calcium.

• 수도
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• v.23 no.6 s.81
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• pp.13-21
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• 1996

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1263-1271
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• 2000

This study investigated the floc structure and removal of turbidity and organic matter by alum coagulation. Results of this study indicated that sweep floc and charge neutralization area were shifted to more acidic region than that in the Amirtharajah's diagram. This was caused by organic matter present in the raw water. Removal regions of turbidity and organic matter were generally overlapped. However, organic matters was removed better at lower pH than turbidity. Floc structure was characterized by measuring fractal dimension and volume diameter using AIA and SALLS. SALLS method was found to be more reliable than AIA method. Floes in sweep floc region had larger size and fractal dimension than flocs in charge neutralization region. As pollutant removal increased, larger fractal dimension and size of floc were measured.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.888-890
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• 2009

This study presented a lab-scale apparatus for turbidity control in the lakes or reservoirs. Overall, the filamentous mat had a capture efficiency of 70~90% compared with the control group. Generally, the capture efficiency decreased with improved input turbidity flux. However, the attachment and sedimentation were thought to be the main processes for turbidity water retention and removal. Thus, the increase of hydraulic detention time in the mat zone is very important to improve the capture efficiency of the turbidity water.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.44-51
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• 2001

Sedimentation characteristics such as SS, $BOD_5$, COD removal efficiency of waste water in the toilet paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity, SS, COD, $BOD_5$ and then equation for treatment efficiency was suggested. Mechanical strength of floc was determined by turbidity. For the coagulant, polyacrylamide (PAM) is more efficient for removing pollution than the aluminium sulfate. Effective mixing ratios of PAM and aluminum sulfate to remove pollution are 70:30 and 30:70. The lowest turbidity was showed when rapid mixing at 300 rpm after coagulant injection was applied. That which indicates the highest point of flocs mechanical strength.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.625-631
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• 1999

This study was performed to determine the optimum coagulant dosing for effective treatment of raw water in Chinyang lake. Removal rates of algae and characteristics of the water according to coagulants dosage were investigated by treatment with Microcystis aeruginosa, which is a kind of blue-green algae, to the raw water below 5NTU. The coagulants dosage for maximum removal rate of algae were 30 mg/$\ell$ of Alum, 30 mg/$\ell$ of PAC and 10 mg/$\ell$ of PACS, respectively. The removal rate of algae in 30 mg/$\ell$ of PAC was highest as 85% compared with the other treatments. At the point of maximum removal rate of algae, the removal rates of turbidity were 34%, 66% and 22% in Alum, PAC and PACS, respectively. Residual Al was decreased depend upon decreasing turtidity in water by treatment of Alum or PAC, but decreased depend upon increasing turbidity in water by treatment of PACS. The removal rate of ${Mn}_{2+}$ in water was high in the order of Alum, PAC and PACS treatment. And ${Fe}_{2+}$ in water was not changed by treatemnt of these coagulants. Particle numbers distributions according to the particle size of suspended solids that were not precipitated at 8 min. of settling time after treatment of coagulants dosage for the maximum removal rate of algae were investigated. Most of the particle sizes were below 30 $\mu$m and particle numbers distributions below 10 $\mu$m were 64%, 56% and 66% by treatment of Alum, PAC and PACS, respectively. Zeta potential was in the range of -6.1~-9.7 mV at optimum coagulants dosage for algae removal.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.549-554
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• 2014

This study was evaluated the applicability of the membrane filtration process (Micro Filtration (MF), nanofiltration membranes (NF), reverse osmosis (RO)) on the major radioactive substances, iodine ($I^-$) and cesium ($Cs^+$) using membranes produced in Korea and domestic raw water. Iodine ($I^-$) or cesium ($Cs^+$) in the microfiltration membrane (MF) process could not be expected removal efficiency by eliminating marginally at the combined state with colloidal and turbidity material. At the domestic raw water (lake water, turbidity 1.2 NTU, DOC 1.3 mg/L) conditions, nanofiltration membrane (NF) and reverse osmosis (RO) showed a high removal rate of about 88 ~ 99% for iodine ($I^-$) and cesium ($Cs^+$) and likely to be an alternative process for the removal of radioactive material.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.281-286
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• 2003

This study was conducted to evaluate the feasibility of ammonia removal by zeolite adsorption in drinking water treatment. In generally, drinking water treatment process is conducted coagulation/flocculation, sedimentation, sand filtration and disinfection. We tested feasibility with two method, one is powdered zeolite dosing to coagulation tank and the other is to substitute granular zeolite for sand of sand filter. In powdered zeolite test, raw water is used tap water with putting of 2 mg/l of NH$_4$$\^$+/-N. Filtration of granular zeolite was conducted with 80 cm of effective column high and 120 m/d of flow rate. At above 100 mg/1 of zeolite dosage, ammonia concentration was decreased below 0.5 mg/l of NH$_4$$\^$+/-N in powdered zeolite test. But, turbidity was increased to 30 NTU by powdered zeolite dosage. That turbidity was scarcely decreased in generally coagulant using condition in drinking water treatment. In granular zeolite test, ammonia was not detected in treated water until 8 days. This result suggest that using of granular zeolite in sand filter could be removal ammonia in winter. But we need regeneration at zeolite filtration for ammonia removal. So, it is to make clear that zeolite regeneration ability was compared KCl with NaCl. The result reveal that KCl was more excellent than NaCl. Optimum regeneration concentration of KCl was revealed 100 mM. Regeneration efficient was not increased at pH range 10∼12.5.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.726-731
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• 2005

Sedimentation is treated as the most important unit process in waterworks, and plays great role on turbidity removal efficiency. Rectangle sedimentation basin is the most widely accepted sedimentation process. But it has some problems with short-circuit flow and density flow caused by temperature and influent turbidity variation. To solve these problems, installation of rectification wall was suggested, but not generally fully accepted in field. Because hole of rectification wall cause jet flow. In this research, use of moving baffle was investigated. Moving baffle was designed to induce uniform velocity at every section of water flow. The baffle walls was made from soft fiber materials. The baffle walls with flow of sedimentation basin moves at same speed. It is like that it controls density flow and short-circuit flow and induce uniform velocity at every section of water flow in sedimentation basin. When moving baffle was operated retention time of sedimentation basin was extended to 1 hours. When it talked again and the effluent time of highest concentration of the chlorine ion from 100 minutes was extended to 160 minutes. Turbidity removal efficiency was tested with different operation modes(continuous and batch) with influent turbidity and retention time. It was revealed that turbidity removal efficiency carl be improved up to 36%(continuous mode) and 58%(batch mode) respectively. Consequently if moving baffle introduces in Rectangle sedimentation basin, it forecasts that the turbidity improvement above 30% will be possible.