• 상하수도학회지
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• 제20권2호
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• pp.281-287
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• 2006

Maintaining adequate chlorine residual is crucial in water treatment facilities, Treatment technique, newly promulgated regulation, requires sufficient disinfection in order to control more resistant microorganisms such as Viruses and Giardia lamblia. Each water treatment plant should report various water qualities including chlorine residual and disinfection by-products, thus plenty of data has been generated. Even though statistical analysis using these data are forced to investigate the status and effect of water qualities in water facilities very few researches have been performed in korea. This study performed statistical analysis of chlorine residual during three years in Korean drinking water. The average chlorine residual concentrations were 0.701mg/L, 0.738mg/L, 0.763mg/L in 2002, 2003, 2004, respectively. Monthly variations of chlorine residual was not significant. ANOVA result showed that yearly variance of chlorine residual is different in only less than $5000m^3/day$ of water treatment capacity. The statistical analysis can help government to establish new regulation with scientific basis.

• 상하수도학회지
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• 제9권3호
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• pp.88-98
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• 1995

Several kinds of coagulants such as aluminum sulfate, PAC, PASS are being used to treat drinking water resulting in residual aluminum ions in the water. Recently, it has been reported that high intake of aluminum ion may cause neurological dieseases such as Alzheimer's diesease and presenile dementia. Because of the possible adverse effect, WHO and EEC recommand to regulate residual aluminum. The autorities in Korea also has plan of regulating residual alunimum from 1995. But there is not enough information about the range of residual aluminum ion concentration when the aluminum sulfate, PAC or PASS has been used as a coagulant. Therefore the study has been conducted to find out the range of residual aluminum ion concentration after using aluminum sulfate, PAC, and PASS. Furthermore the effect of turbidity and alkalinity have been investigated. The experimental results are summarized as; 1. Most of the residual aluminum ion concentrations were within $10^{-6}$ and $10^{-5}mole/l$. Three coagulants have not showed any considerable difference in the residual aluminum concentration up to 50 NTU. However PAC has showed the least residual aluminum in high turbidity water over 100 NTU. 2. The low alkalinity water having 25mg/l as $CaCO_3$ has showed less residual aluminum than the water having 50mg/l alkalinity. However, the difference was not significcant. 3. Even the lowest residual aluminum concentration was over 0.05mg/l. Therefore the process to reduce residual aluminum would be necessary in water treatment plants.

• 한국환경과학회지
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• 제15권12호
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• pp.1199-1203
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• 2006

This paper analyzes the separation efficiency of vehicles mat residual product, and caloric value, element analysis and heavy metal of separated PE & PVC mat residual product. A results of separation efficiency, fiber fraction of PE & PVC mat residual product was analyzed 71.9% and 18.6%, respectively. Caloric value of PE & PVC mat residual product was analyzed 3,894kca1/kg and 10,203kca1/kg, respectively. A results of element analysis, main component of PVC mat were carbon(33.2%) and oxygen(21.0%), and main component of PE mat fiber were carbon(75.4), hydrogen(11.3%) and oxygen(9.1%). Lead and cadmium concentration of PVC powder was detected 98.9mg/kg and 19.8mg/kg, but Lead and cadmium concentration of fiber was detected 15.7mg/kg and 6.1mg/kg.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.47-51
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• 2014

In this work, a possible mechanism for grain evolution in Al-Mg alloy films during thermal annealing is suggested on the basis of the phase transition and the related residual stress. Al-Mg alloy films with compositions of 14.0 and 18.0 wt% Mg content were deposited on cold-rolled steel substrates by the direct current co-sputtering method using Al and Mg targets. After the deposition, the samples were thermally annealed at $400^{\circ}C$ for 10 min. The featureless, dense cross-sectional microstructure of the as-deposited films turned into a grainy microstructure after the thermal annealing. According to the residual stress evaluated by using the $XRD-sin2{\psi}$ technique and the phase analysis by XRD, it is likely that grains were created in order to relieve the additional accumulation of residual stress originating from the phase transition from face-centered cubic Al (${\alpha}$) to Al3Mg2 (${\beta}$) and Mg (${\delta}$) phases, suggesting interplay between the microstructure and residual stress.

• 대한환경공학회지
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• 제33권2호
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• pp.93-102
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• 2011

본 연구에서는 부산신항만 준설퇴적물에 포함된 중금속의 총농도, 이동성, 생체이용률, 독성을 알아보기 위하여 총함량분석과 연속추출실험을 실시하였다. 준설퇴적물의 중금속 총농도는 다음과 같이 비교적 낮았다: Al (2.36~2.96 wt.%), As (1.6~3.3 mg/kg), Ba (30.0~33.8 mg/kg), Cd (0.12~0.18 mg/kg), Cr (27.5~35.0 mg/kg), Cu (11.3~15.0 mg/kg), Fe (2.91~3.51 wt.%), Mn (324~408 mg/kg), Ni (18.8~23.8 mg/kg), Pb (23.8~31.3 mg/kg), Zn (70.0~86.3 mg/kg). 또한 대부분의 중금속이 residual fraction으로 존재하였는데, 이는 오염원이 자연발생적일 가능성이 높음을 의미한다: Al (87.5~95.9%), As (74.1~93.8%), Ba (71.8~77.6%), Cr (69.5~94.3%), Cu (50.0~78.7%), Fe (70.8~87.6%), Ni (64.5~75.3%), Pb (53.4~64.3%), Zn (62.5~81.7%). 반면에 Cd과 Mn은 주로 non-residual fraction으로 존재했다. 준설퇴적물의 유해중금속 농도가 낮고 residual fraction 비율이 높기 때문에, 이를 벽돌, 도로포장재료 등으로 재활용하는 것이 가능하다고 사료된다.

• 상하수도학회지
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• 제14권2호
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• pp.164-173
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• 2000

Fluoridation of drinking water to a level of about 0.8mg/l (below 1.5mg/l) for reducing the incidence of tooth decay is recommended. However, concerns about potential problems of unknown effects and overdosing hinders the fluoridation. This study describes the work performed to obtain information on the behavior of fluoride under various conditions in the process of water fluoridation. Effects of water treatment chemicals, water treatment unit, and water distribution on water fluoridation were investigated at both lab and an actual water treatment plant. Residual fluoride concentration was not affected by lime and chlorine dosage up to 20mg/l. Flocculation with PAC slightly decreased the residual fluoride concentration as PAC dosage increased. Average fluoride concentration of 0.87mg/l at an intake basin was decreased to 0.83mg/l by sedimentation, 0.81mg/l by dual media(sand+anthracite) filtration, and 0.79mg/l by granular activated carbon filtration in the water treatment plant.

• Membrane and Water Treatment
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• 제12권2호
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• pp.83-93
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• 2021

In this study, defluoridation efficiency by aluminium sulphate (alum) and polyaluminium chloride (PACl) were compared for recommended Nalgonda dose (100%) and 80% of this dose in both batch and continuous modes. The residual turbidity was found to be higher in case of alum as compared to PACl with 80% dose representing lesser efficient settling of suspensions, which primarily comprise alumino-fluoro complexes that result in high residual aluminium in the treated water and this was confirmed by TEM and Zeta analysis. Moreover, the application of PACl also resulted in much lesser addition to the TDS and also required lesser lime for pH compensation due to its lower acidity. Hence this reduced dose was recommended for defluoridation. It was also observed that in case of alum, residual aluminium in treated water was 0.88 mg/L (100% dose) & 0.72 mg/L (80% dose) and in case of PACl, it was 0.52 mg/L(100% dose) & 0.41 mg/L(80% dose). After subsequent microfiltration, residual aluminium was 0.28 & 0.21 mg/L for 100% & 80% dose respectively and in case of alum and in case of PACl, it was 0.16 & 0.11 for 100% & 80% dose respectively, which conform to the Al standards(<0.2 mg/L).

• 한국식품저장유통학회지
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• 제10권2호
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• pp.236-240
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• 2003

초유성분을 이용한 유제품의 개발시 기초자료로 활용하기 위하여 IgG 강화우유의 살균온도에 따른 IgG 활성 잔존율과 초유관련 분말제품의 용해온도에 따른 IgG 활성 잔존율을 측정하였다. 그 결과, 원유, IgG 50 mg, 250 mg 강화한 우유는 살균처리 온도가 높을수록 활성 잔존율이 급격히 감소하였으며, LTLT 처리시 원유, 50 mg, 250 mg 강화우유의 활성 잔존율은 각각 79%, 30%, 21.6%였다. 그러나 9$0^{\circ}C$/15초 이상의 살균 처리시에는 IgG 활성이 거의 파괴되었다. 분말제품의 3$0^{\circ}C$, 4$0^{\circ}C$, 5$0^{\circ}C$, 6$0^{\circ}C$ 용해온도에 따른 IgG 활성 잔존율은 큰 차이를 나타내지 않았다.

• 한국환경보건학회지
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• 제19권2호
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• pp.1-9
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• 1993

In public water supply systems, Alum and/or PAC being used as a coagulant. It is well known that their use increased frequently the concentration of residual aluminum in filtered water upon operating conditions. This study was conducted to find the optimum conditions that both the concentration of residual aluminum and turbidity are minimized by changing such factors as pH, temperature, alum dosage, mixing rate, alkalinity and hardness. The results can be summarized as follows: The pH values for the minimum concentration of residual aluminum and turbidity as a given experimental condition were found at pH 6 and pH 7 respectively, the apparent clarity was best at pH 8. The floc settling rate was the greatest at pH 6.5, but the turbidity was high at the same condition. The more alum dosage, the higher the concentration of residual aluminum. However the alum dosage less than 15 mg/l tend to decrease in turbidity. Restabilization and enmeshment occurred near 15 mg/l and 20 mg/l of alum dose respectively. With the increase of mixing rate (rapid and slow), the concentration of residual aluminum and turbidity are increased and the same trend was found in increment of mixing time. At low water temperature, the concentration of residual aluminum was decreased, but turbidity was increased. It was confirmed that alkalinity had an effect on the coagulation efficiency, but hardness did not.

• 대한환경공학회지
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• 제35권7호
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• pp.495-502
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• 2013

본 연구는 UF공정의 전처리로써 Al(III)계 응집제인 alum과 PACl을 사용한 응집공정 적용 시 두 응집제의 효율 비교 및 잔류 알루미늄 농도를 고려한 최적 운전 조건을 알아보기 위해 응집제 주입농도, 완속교반의 적용 그리고 해수 원수의 pH를 변화하여 UF막 flux 및 잔류 알루미늄 이온 농도를 조사했다. 그 결과 pH 8.0 조건에서 alum의 주입농도가 증가할수록 flux 또한 증가하였으며 완속교반은 UF막 flux를 오히려 감소시킨 것으로 조사된 반면 PACl의 경우 주입농도가 증가할수록 flux는 일부 감소하는 경향을 보였으며 alum과는 반대로 완속교반 적용시 flux 또한 증가하였다. 반면에 pH 6.5 조건에서 alum 주입량이 0.7 mg/L (as Al)일 때 UF막 flux의 효율이 가장 좋았고 잔류 알루미늄 농도는 0.05 mg/L (as Al) 이하로 측정되었다. PACl의 경우 UF막 flux 측면에서는 최적 조건은 pH 8.0, 주입농도 1.2 mg/L (as Al) 그리고 완속교반 시간을 적용하였을 때였으며 잔류 알루미늄 농도를 고려한 최적 주입조건은 pH 6.5 조건에서 주입농도를 1.2 mg/L (as Al)일 때로 조사되었다.