Concrete is one of the largest wastes, by volume, generated during the decommissioning of nuclear facilities, which significantly influences the projected costs for the disposal of decommissioning wastes. Concrete consists of aggregates and a cement binder. In radioactive concrete, the radioisotopes are mainly associated with the cement component. If the radioactive isotope can be separated from the concrete to below the clearance criteria, the volume of radioactive concrete waste could be reduced effectively. We were studied to separate the radioactive materials from the concrete by using the thermomechanical and chemical treatment processes, sequentially. From the study, separated aggregate could be treated to achieve the clearance level. However, these processes generate a large volume of secondary acidic radioactive wastewater, which might be a critical problem to reduce the volume of radioactive concrete waste. In this research, separating the 137Cs and 90Sr from dissolved concrete wastewater to below the discharge criteria by precipitation method, it would be released to the environment under industrial waste guidelines. The experiments were conducted to using a simulated radioactive wastewater, formed by the dissolution of concrete within HCl, which was spiking the 137Cs and 90Sr, respectively. In addition, we applied the chemical precipitation methods with wastewater, using ferrocyanide for 137Cs and BaSO4 coprecipitation for 90Sr. As a result, targeted radionuclides could be removed to the discharge level (137Cs: 0.05 Bq·ml−1, 90Sr: 0.02 Bq·ml−1) by precipitation method. Therefore, it could reduce the secondary wastewater effectively by precipitation method and enhance the additional volume reduction for radioactive concrete waste.

Coagulation/precipitation process has been widely used for the removal of phosphate within domestic wastewater. Although Fe and Al are typical coagulants used for phosphate removal, these have some shortages such as color problem and low sedimentation velocity. In this study, both Fe and Al were used to overcome the shortages caused by using single one, and anionic polymer coagulant was additionally used to enhance sedimentation velocity of the precipitate formed. Batch experiments using a jar test were conducted with real wastewater, which was an effluent of the second sedimentation tank in domestic wastewater treatment plant. Response Surface Methodology was used to examine the responsibility of each parameter on phosphate removal as well as to optimize the dosage of the three coagulants. Economic analysis was also done on the basis of selling prices of the coagulants in the field. Phosphate removal efficiency of Fe(III) was 30% higher than those of Fe(II). Considering chemical price, optimum dosage for achieving residual phosphate concentration below 0.2 mg/L were determined to be 18.14 mg/L of Fe(III), 2.60 mg/L of Al, and 1.64 mg/L of polymer coagulant.

주풍에 따른 강수의 산성도, 전기전도도, 이온 성분의 변화를 알아보기 위하여 2009년 부산지역 강수를 분석하였다. 부산지역에서는 남서풍과 북동풍이 우세하게 나타났다. 주풍이 서풍인 경우, 강수의 산성도는 약 pH 7로 중성으로 나타났으나 전기전도도는 약 200 μscm-1로 다른 풍향에 비해 월등히 높게 나타나 강수에 이온성분이 많이 함유된 것을 알 수 있었다. 양이온 K+와 음이온 Cl-가 다른 이온에 비해 높게 나타났으며, 북풍과 남서풍이 불 때 다른 풍향에 비해 전체적으로 높은 농도로 나타났다. 산성비의 주 원인물질인 NO3-/SO42-의 구성비는 북풍에서 3 이상으로 월등히 높은 값이 나타났다. 다른 풍향에 비해 북동풍, 동풍, 남서풍, 서풍에서의 K+의 중화기여도는 전체적으로 1 이상으로 높은 값을 나타내었는데, 이는 산성이온을 중화시키는데 있어서 알카리성 이온인 K+의 중화기여도가 크게 작용하였음을 알 수 있다. 또한 해염입자는 북풍, 북동풍, 남서풍에서 800 μsm-3 이상으로 다른 풍향에 비해 상대적으로 많은 양을 나타내었다. 역궤적 분석 결과, 북풍, 서풍, 북서풍계열에서는 봄, 가을, 겨울철에 만주, 내몽골 고원, 중국, 러시아 지역으로부터 공기덩어리의 이동을 볼 수 있었다. 반면, 동풍, 북동풍, 남서풍계열에서는 여름철에 해양으로부터 공기덩어리의 이동을 볼 수 있었다. 따라서 부산지역의 강수중 산성도, 전기전도도, 이온 성분 농도는 내륙과 연안해역의 특성을 가진 주풍에 의한 변동 특성을 잘 나타내고 있음을 알 수 있었다.

The seasonal variation of pH and ion components in precipitation were investigated from January to December 2009 at Busan, Korea. The precipitation was acidic with a volume-weighted mean pH concentration of 5.32, which ranged from 3.79 to 8.66. The volume-weighted mean conductivity showed 86.77 μS/cm and indicated higher concentration about 96.69 μS/cm in summer. The volume-weighted mean equivalent concentration of components followed the order: K+ > Ca2+ > nss-Ca2+ > NH4 + > Mg2+ > Na+ > Li+ in cations and Cl- > SO4 2- > nss-SO4 2- > NO3 - > NO2- > F- > Br- in anions. Particularly, concentration of K+ and Cl- showed 56 and 78 % in cations and anions. The higher concentration in K+, Na+, Mg2+ and Cl- were shown in Busan city as compared to the other cities. The neutralization factors have been found to have higher value for potassium ion in winter compared with different seasons, indicating significant neutralization of acidic components over the region by potassium. Therefore, the precipitation characteristics at Busan had both continental and coastal as consequence of pH, conductivity and ionic analyses.

The objective of this study was to analyze long-term annual and seasonal trends of water chemistry on landuse patterns and seasonal precipitation using 72 sampling sites within Namhan River watershed during 2001-2010. Water quality, based on multi-parameters of water temperature(WT), dissolved oxygen(DO), biochemical oxygen demand(BOD), chemical oxygen demand(COD), suspended solids(SS), total nitrogen(TN), total phosphorus(TP), and electric conductivity(EC) varied largely depending on monsoon rain and landuse patterns such as forest, cropland, and residence. Concentrations of BOD and COD as an indicator for organic matter pollution, increased during summer monsoon season at the cropland and residential streams. Values of TN and TP were higher in residential streams than in the forest and cropland streams. In the meantime, DO values had weak relations to the landuse patterns of forest and cropland cover. Water quality was worst in cropland and residential streams, and also most degradated in 4th order streams. Overall, our results suggest that efficient water quality management is required in the cropland and residential landuse streams.

Changes of chemical properties by times of the reclaimed tidal land soils and soil surface water, underground infiltration water with precipitation-runoff on natural meteological condition in the unripened tidal reclaimed paddy fields were investigated. This study was carried out to use environment-friendly farm land in the reclaimed tidal lands. The soils used in this study were saline-alkaline soils with the high Na+ and Mg++ content. As the results of investigation outflow loading of nutriments through outflow water in the unripened tidal reclaimed paddy fields by precipitation during the survey period, nutriments equivalent to T-N 1~2 kg 10a -1 and T-P 0.01~0.02 kg 10a-1 from in the unripened tidal lands were discharged. Besides, the results of comparison losses of cation through outflow water showed Na+> K+> Mg++ > Ca++, and the highest appeared water discharge of Na+. In case of saemangeum reclaimed tidal land soils water discharge of cations showed Ca++ 1.3 kg 10a-1, Mg++ 1.6 kg 10a-1, Na+ 17.7 kg 10a-1, and K+ 3.2 kg 10a-1 respectively. On the other hand, in case of koheung reclaimed tidal lands soils water discharge of cations showed Ca++ 18.1 kg 10a-1, Mg++ 31.2 kg 10a-1, Na+ 320.8 kg 10a-1 and K+ 51.2 kg 10a-1 respectively.

The concentrations and wet deposition flux into the sea of heavy metals of precipitation in Pusan area were measured and estimated. The samples were collected by polyethylene bottle(30ℓ) from January to November in 1996, and heavy metals were analyzed by atomic absorption spectrometer. The concentration order of heavy metals was Al >Fe >Zn >Pb >Mn >Cu >Ni >Cd >Co, and they were high at inland sites and low at coastal sites. The enrichment factors for some metals(Zn, Cu, Pb, Cd), based on crustal Al, were significantly greater than unity, and the order was Cd > Pb > Zn > Cu. This evidence suggests Cd and Pb are derived predominantly from non-crustal sources. Al, Fe and Mn contents showed good correlation with each other. Therefore this enrichment factor indicates similar geochemical behavior of these elements. The annual wet depositional flux(㎎/㎡/yr) from P1 site was as follows: Al (121.1), Fe,(177.2), Zn(12.9), Mn(6.19), Pb(14.4), Cu(0.64), Ni(1.03), Cd(1.02) and Co(1.01).

The chemical characteristics of precipitation was investigated in Pusan area. Samples were collected from January to November in 1996 at 4 sites, and analyzed pH, mayor soluble ionic components(Cl^-, NO_3^-, SO_4^2-, Na^+, K^+, NH_4^+, Mg^2+, Ca^2+). The order of anion and cation concentrations for the initial precipitation were Cl^- > SO_4^2- > NO_3^- , and Ca^2+ > Na^+ > NH_4^+ > Mg^2+ > K^+, respectively. At coastal sites(P1 and P2) Cl^- and Na^+ of maritime sources (seasalt) were high, but at inland sites(P3 and P4) nss-Ca^2+ and nss-SO_4^2- were high. Calcium ion for the initial precipitation showed high value of enrichement factor(EF) relative to seawater composition. The contribution of seasalt to the composition of precipitation was higher at site P1 (53.5%) than those of the other sites. Throughout the year the concentrations of major ions for the initial precipitation were low in the heavy rain season. The mean pH for the initial precipitation was 5.4 and showed the negative relationship with the precipitaion amount. The SO_4^2- and NO_3^- do not play an important role in rain acidification due to the high(97%) neutralizing effect of amonia and calcium species.

Precipitation samples were collected at sixteen sites in Northeast Asia from June 1995 to February 1997, and were analysed for the anions SO_4^2- NO_3^- and Cl^- and for the cations Na^+, NH_4^+, K^+, Mg^2+ and Ca^2+ in addition to pH and conductivity measurements. The quality assurance of chemical composition data was checked by considering the ion balance evaluating by │h│ value and the conductivity balance. The sum of cation concentrations were slightly greater than the sum of anion concentraions. For the anions, SO_4^2- clearly dominates in most of sampling sites whereas Cl^- is more abundant in coast and rural sites in Japan. For the cations, Ca^2+ and NH_4^+ are generally the more abundant ions except when sources of Na^+ exist. The contribution rate of nss-SO_4^2- and NO_3^- to acidity are about 70% and 10-30%, respectively. The neutralizing capacity by a major neutralizing cations such as NH_4^+ and nss-SO_4^2+ are above 98%(heavy polluted and urban sites in China), above 70%(urban sites in Japan and in Korea, coast sites in China) and above 60%(rural sites in Japan and in Korea), respectively.

A preliminary study on the chemical compositions of forty seven precipitations from March 1994 to May 1995 in Yeoncheon-gun, which is adjacent to the southern boundary of demilitarized zone (DMZ) in the northernmost tip of Kyunggi province has been performed. The metal cation and anion concentrations were measured by atomic absorption spectrometer and ion chromatography, respectively. pH/Ion meter and direct nesslerization method were used for the concentration measurements of H- ion and NH_4+ ions, respectively. Based on the data, the quantitative orders of the cation and anion average concentrations were Ca2+ > NH_4+ > Na+ > K+ > Mg2+ > H+ and SO_42- > Cl- > NO_3-, respectively. The ratio of average total anion concentration to average total cation concentration was 0.97. The average pH value of the precipitations was 5.60. These results, correlation coefficients between the ion concentrations, and monthly variations of pH value and precipitation amount are used for chemical analysis on the environmental pollution and pollutant sources in Yeoncheon-gun of Kyunggi province near DMZ.

This study was carried out to investigate the characteristics of chemical components and precipitation at Kimhae area from March, 1992 to June, 1994. The pH values, concentration of soluble ions(Cl^-, NO_2^-, NO_3^-, SO_4^2-, PO_4^3-, F^-, Mg^2+, Ca^2+, Mn^2+, K^+) and nonsoluble metals(Cr, Si, Zn, Pb, Cu, Fe, Mn, Mg, Al, V, Ca) were measured by pH meter, IC(Ion Chromatography) and ICP(Inductively Coupled Plasma). The data were analyzed by the daily, hourly distribution characteristics of acidity and chemical components, as well as the correlation between them. The results are as follows. 1. The pH range of precipitation was from 3.45 to 6.80 in Kimhae area, and average value was pH 4.62 and main chemical components were SO_4^2-, Cl^-, NO_3^-. The highest pH value and concentration appeared in initial rain, which might result from urbanization and industrialization in this area and long term transportation from China. 2. The hourly correction distribution of main anions related to pH value in the rainwater showed SO_4^2- > NO_3^- > Cl^-. Hourly concentration of heavy metal and each ion was highly correlated with pH in the precipitation.