• Journal of Korean Society on Water Environment
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• v.38 no.4
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• pp.171-176
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• 2022

Recently, an autotrophic single-stage nitrogen removal (ASSNR) process based on the anaerobic ammonium oxidation (ANAMMOX) reaction has been proven as an economical ammonia treatment. It is highly evident that double-layered gel beads are a promising alternative to the natural biofilm for ASSNR because of the high mechanical strength of poly(vinyl alcohol) (PVA)/alginate structure and efficient protection of ANAMMOX bacteria from dissolved oxygen (DO) due to the thick outer layer. However, the thick outer layer results in severe mass transport limitation and consequent lowered bacterial activity. Therefore, the effects of the thickness of the outer layer on the overall reaction rate were tested in the biofilm model using AQUASIM for ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and ANAMMOX bacteria. A thickness of 0.5~1.0 mm is preferred for the maximum total nitrogen (TN) removal. In addition, a DO of 0.5 mg/L resulted in the best total nitrogen removal. A higher DO induces NOB activity and consequent lower TN removal efficiency. The optimal density of AO B and NO B density was 1~10% for a 10% ANAMMOX bacterial in the double-layered PVA/alginate gel beads. The real effects of operating parameters of the thickness of the outer layer, DO and concentrations of biomass balance should be intensively investigated in the controlled experiments in batch and continuous modes.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.2
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• pp.221-226
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• 1994

Copper T 380A intrauterine devices were inserted to nine thousand and nine hundred twenty women by 51 KAVS-member physicians since January 1, 1993 through December 31, 1993. This study was undertaken for the clinical analysis on a total of 9,920 women wearing Copper T 380A to grasp the effectivness as well as the expulsion rate due to a various side effects. The following features were the results of the study: 1. During the twelve months period, from January 1993 to December 1993, the largest number of IUD insertion per one physician is 740 cases and the smallest number 60 cases, the mean 195 cases. 2. After insertion of Copper T 380A, a total of 117 cases were removed the IUD;81 cases(0.8%) were due to extensive bleeding and 36 cases(O.36%) were due to pain. The pregnancy failure rate represented comparatively lower rate, 0.08% (8 cases) and the expulsion rate was 0.06%(6 cases). 3. The removal rate of Copper T 380A was different by physicians. The highest removal rate for bleeding was 3.13% and 13 physicians(25.5%) did not experience any bleeding cases. 4. For the removal rate for pain, 30 physicians(58.8%) did not experience any removal of IUD due to pain while 21 physicians(41.2%) removed IUD due to pain: 17 physiciansC33.4 %) had 0.1-1.5% of removal rate and 4 physiciansC7.0%) had 1.6-2.1% of removal rate. 5. A total of 43 physicians(84.3 %) did not experience any pregnancy failure case while 8 (15.7%) physicians was experienced pregnancy failure rate. Four physicians(7.8%) had 0.1-0.5% of pregnancy failure rate and 4 physicians had 0.6-1.0% of pregnancy failure rate. 6. Expulsion rate showed comparatively lower, 0.06% in this study. A total of 45 physicians (88.2%) did not experience any expulsion cases while 6 physicians(11.7%) had expulsion rate with the highest expulsion rate of 2.0%.

• Membrane Journal
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• v.21 no.3
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• pp.263-269
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• 2011

In the operation of submerged membrane-coupled sequencing batch reactor, the effect of filling step on the removal efficiency and filtration performance were investigated. Two sets of operation modes, the filling step located in the beginning of aerobic step (Mode-1) and the beginning of anoxic step (Mode-2), during 89 days were conducted. There was no wide difference in the COD removal and filtration performance between two sets of operation modes. But in the removal efficiency of nutrients (total nitrogen and total phosphorous), Mode-2 was more effective than Mode-1. In the case of Mode-2, average removal efficiencies of COD, total nitrogen, and total phosphorous were 99.1, 73.3, and 77.3%, respectively.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.850-862
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• 2007

This study was carried out to survey the actual conditions of wastewater treatment facilities to obtain basic data for the management of wastewater from industrial complexes in Chungcheongnam-do province. Wastewater production flow per site area by watersheds was $49.2m^3/km^2/d$ for Sapgyoho, $8.1m^3/km^2/d$ for Anseongcheon, $5.7m^3/km^2/d$ for Seohae, and $2.9m^3/km^2/d$ for Geumgang. Sapgyoho showed 75% of the total production flow, which was the highest value, Geumgang showed 4% of total flow, which was the lowest value. Average total extra rate as production flow/capacity flow in the wastewater treatment facilities for industrial complex is 49%. Considering by watersheds, the extra rates of Seohae, Geumgang, Anseongcheon, and Sapgyoho, are 73%, 65%, 62%, and 33% respectively. This means that the design of capacity flow in wastewater treatment facilities was too large. Effluent concentration of wastewater treatment facilities did not exceed discharge limit mostly. The removal efficiency rate for water quality item was 90% in BOD, 70% in COD, 80% in SS, 30 to 80% in TN, and 20 to 90% in TP, so the organic removal was good, but the nutrient removal was low and interval of variation was high. The removal efficiency rate of the agricultural was industrial complexes is lower than the national and local complexes. The construction cost of the wastewater treatment facilities in Chungcheongnam-do was $1,756Won\;per\;m^3$, treatment cost was $189Won\;per\;m^3$, and they were about two times and 1.2 times higher than the nation-wide cost, respectively. The treatment cost consists of 39% for man power, 21% for chemical, 16% for power, 11% for sludge treatment, and 13% for others.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.407-412
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• 2010

The purpose of this study was to investigate removal efficiencies of contaminants in night soil treatment plant using the B3 system. The samples were collected from retaining tank and settlement tank in Yechon night soil plant. We experimented concentrations of BOD, COD, SS, TN and TP. Concentration data were processed using removal efficiencies by season and correlation analysis with pilot running parameters. Removal efficiencies of total organic carbon was over 96%, TN was 98% during summer, 80.9% during winter. In the case of TP, the highest removal efficiencies was 94.1% during fall and the lowest removal efficiencies was 82% during spring. Results of correlation analysis showed two positive correlation groups and one negative group. Positive correlations were among temperature, BOD and TN. The others were pH, BOD, COD, SS, TN and TP. Negative correlation were among MLSS, BOD, COD, SS, TN, TP.

• Textile Coloration and Finishing
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• v.13 no.2
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• pp.18-18
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• 2001

This study has examined the removal of mixed soil of protein and fat by protease. Cotton and PET fabrics were soiled by spotting of hemoglobin and triolein, respectively. The soiling order and soil concentration were changed in this procedure. The soiled fabrics were aged at 130℃ for 20 minutes. Protease was added in the alcohol ethoxylate(AE) detergent solution. The removal effciency was evaluated by analysis of protein and/or fat on the fabrics before and after washing, respectively. The detergency of PET fabrics was higher than that of cotton fabrics. The removal efficiency of hemoglobin was improved by protease from cotton and PET fabrics. Especially the removal efficiency of hemoglobin was remarkably improved from cotton fabrics. With the increase of hemoglobin and triolein (1:1) mixed soil, the removal of mixed soil was increased in proportion to mixed soil content up to a certain point. but it began to decrease above the point from cotton fabrics, while it was generally increased from PET fabrics. The detergency of total mixed soil from cotton fabrics was higher in case of soiling order with triolein after hemoglobin than in case of soiling order with triolein before hemoglobin. But the soiling order was not greatly effected in the detergency of total mixed soil from PET fabrics.

• Textile Coloration and Finishing
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• v.13 no.2
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• pp.104-113
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• 2001

This study has examined the removal of mixed soil of protein and fat by protease. Cotton and PET fabrics were soiled by spotting of hemoglobin and triolein, respectively. The soiling order and soil concentration were changed in this procedure. The soiled fabrics were aged at $130^\circ{C}$ for 20 minutes. Protease was added in the alcohol ethoxylate(AE) detergent solution. The removal effciency was evaluated by analysis of protein and/or fat on the fabrics before and after washing, respectively. The detergency of PET fabrics was higher than that of cotton fabrics. The removal efficiency of hemoglobin was improved by protease from cotton and PET fabrics. Especially the removal efficiency of hemoglobin was remarkably improved from cotton fabrics. With the increase of hemoglobin and triolein (1:1) mixed soil, the removal of mixed soil was increased in proportion to mixed soil content up to a certain point. but it began to decrease above the point from cotton fabrics, while it was generally increased from PET fabrics. The detergency of total mixed soil from cotton fabrics was higher in case of soiling order with triolein after hemoglobin than in case of soiling order with triolein before hemoglobin. But the soiling order was not greatly effected in the detergency of total mixed soil from PET fabrics.

• KSBB Journal
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• v.18 no.3
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• pp.234-238
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• 2003

Biofilm process is preferred to activated sludge process in small domestic wastewater treatment plant because of its simplicity in operation and maintenance. Column reactor filled with waste ceramics and with waste plastics was used to remove pollutants in restaurant wastewater. COD removal at 18 hours of hydraulic retention time (HRT) gave 93.7%, COD removal during the experimental period, where maximum COD removal was observed. Under same condition, average removal of total nitrogen and total phosphorus were 82.3% and 25.9%, respectively Organic and nitrogen were efficiently removed with the HRT of 18 hours or more.

• Composites Research
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• v.31 no.2
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• pp.76-81
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• 2018

In this study, the elemental mercury removal behaviors of silver-plated porous carbons materials were investigated. The pore structures and total pore volumes of the hybrid materials were analyzed by $N_2$ adsorption/desorption analysis at 77 K. The pore structures and surface morphologies of the hybrid materials were characterized by XRD and SEM, respectively. The elemental mercury adsorption capacities of all silver-plated porous carbons hybrid materials were higher than those of the as-received samples, despite the fact that the specific surface areas and total pore volumes decreased with increasing metal loading time. It was found that silver nanoparticles showed excellent elemental mercury removal behaviors in carbonaceous hybrid materials.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.131-134
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• 2004

Several physical and chemical methods have been used for remediation contaminated by oils. However the cost was very high and secondary pollution rose during treating. The purpose of this study was to comprision TPH (total petroleum hydrocarbon) removal from artificially contaminated soil by diesel with and without seeding anaerobic digested sludge. After 120 days of overall at 35$^{\circ}C$, removal efficiency of TPH with seeding sludge was 2-3 times higher than blank. Also, the more amount seeding sludge, TPH removal efficiency and CH$_4$ content more obtained. It was sad that seeding of anaerobic digested sludge was a good method for enhancing TPH removal efficiency without increasing operating cost. Sulfate, nitrate-reducing, methanogenic condition were evaluated for alkane, isoprenoid as target contaminated soil.