• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.429-434
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• 2009

Purpose : Severe aspiration of the amniotic fluid is known to cause fatal respiratory distress in neonates. We conducted this study to investigate the clinical findings of severe amniotic fluid aspiration pneumonia (AFAP) in neonates and the effect of pulmonary surfactant replacement therapy (SRT). Methods : Retrospective analysis of medical records was conducted on 28 patients who received ventilator care due to severe AFAP in a neonatal intensive care unit over a 7-year period (2000-2006). Patients whose amniotic fluid was contaminated with meconium were excluded. Results : A large number of cases were term infants (82.1%) and infants born by caesarean section (85.7%), and the 1- and 5-min Apgar scores of these patients were $6.5{\pm}1.2$ and $7.5{\pm}1.3$, respectively. Soon after birth, the amount of amniotic fluid sucked out from airway below the vocal cord was $16.0{\pm}10.1$ mL. All patients received SRT with a modified bovine-derived surfactant (120 mg/kg/dose), and one dose was administered in most cases (75%). Compared with pre-SRT, the oxygenation index ($8.0{\pm}9.6$ vs. $18.9{\pm}7.3$) according to ventilator care was a significant improvement at 12 h after SRT (P<0.001). Furthermore, most cases showed radiological improvement for aeration at 12 h post-treatment. Many cases (46.4%) had cardiorespiratory complications, but their final outcomes were excellent (survival rate, 96.4%). Conclusion : AFAP may be an important cause of serious respiratory distress in near-term and term infants, and SRT seems to be an effective adjuvant therapy in mechanically ventilated neonates with severe AFAP.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.53-64
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• 2020

A 2㎥/d combined wastewater treatment pilot plant containing the multi-stage vertical stacking type nitrification reactor was installed and operated for more than 1 year under the operating conditions of the short-circuit nitrogen process (pH 8, DO 1mg/L and Internal return rate 4Q from nitrification to denitrification reactor). For economically the combination treatment of food wastewater and the leachate from a landfill, the optimal combination ratio was operated by adjusting the food wastewater with the minimum oil content to 5-25% of the total throughput. The main treatment efficiency of the three-phase centrifugal separator which was introduced to effectively separate solids and oil from the food wastewater was about 52% of SS from 116,000mg/L to 55,700mg/L, and about 48% of normal hexane (NH) from 53,200mg to 27,800 mg/L. During the operational period, the average removal efficiency in the combined wastewater treatment process of BOD was 99.3%, CODcr 94.2%, CODmn 90%, SS 70.1%, T-N 85.8%, and T-P 99.2%. The average concentrations of BOD, CODcr, T-N, and T-P of the treated water were all satisfied with the discharge quality standard for landfill leachate ("Na" region), and SS was satisfied after applying the membrane process. On-site leachate had a relatively high nitrite nitrogen content in the combined wastewater due to intermittent aeration of the equalization tanks and different monthly discharges. Nevertheless nitrite nitrogen was accumulated, denitrification from nitrite nitrogen was observed rather than denitrification after complete nitrification. The average input of anti-forming chemical during the operation period is about 2L/d, which seems to be economical compared to the input of methanol required to treat the same wastewater.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1035-1043
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• 2007

A leachate containing an elevated concentration of organic and inorganic compounds has the potential to contaminate adjacent soils and groundwater as well as downgradient areas of the watershed. Moreover high-strength ammonium concentrations in leachate can be toxic to aquatic ecological systems as well as consuming dissolved oxygen, due to ammonium oxidation, and thereby causing eutrophication of the watershed. In response to these concerns landfill stabilization and leachate treatment are required to reduce contaminant loading sand minimize effects on the environment. Compared with other treatment technologies, leachate recirculation technology is most effective for the pre-treatment of leachate and the acceleration of waste stabilization processes in a landfill. However, leachate recirculation that accelerates the decomposition of readily degradable organic matter might also be generating high-strength ammonium in the leachate. Since most landfill leachate having high concentrations of nitrogen also contain insufficient quantities of the organic carbon required for complete denitrification, we combined a shortcut biological nitrogen removal (SBNR) technology in order to solve the problem associated with the inability to denitrify the oxidized ammonium due to the lack of carbon sources. The accumulation of nitrite was successfully achieved at a 0.8 ratio of $NO_2^{-}-N/NO_x-N$ in an on-site reactor of the sequencing batch reactor (SBR) type that had operated for six hours in an aeration phase. The $NO_x$-N ratio in leachate produced following SBR treatment was reduced in the landfill and the denitrification mechanism is implied sulfur-based autotrophic denitrification and/or heterotrophic denitrification. The combined leachate recirculation with SBNR proved an effective technology for landfill stabilization and nitrogen removal in leachate.