• Nuclear Engineering and Technology
• /
• v.55 no.8
• /
• pp.2889-2896
• /
• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.739-744
• /
• 1995

The two main methods to prepare water samples for analyzing volatile organic compounds(VOC's) were investigated. One is the purge and trap(PT) method and another is the head space(HS) sampling method. Both methods were effective to transfer the low boiling point components from the water sample onto the capillary column. The cryo-focusing at the top of the main capillary column was an effective way to obtain the sharpness of the chromatographic peaks but could be avoided when a semi-wide bore column was used. The recovery from the same amount of the sample was better in PT than in HS but a larger sample volume in HS method could compensate the lower efficiency. Therefore PT is suitable to the analysis of drinking water where the very low concentration must be determined. HS is suitable to waste water analysis because of the easiness of the operation. The repeatability was good and similar in both methods. For the contamination of the former sample, both methods were tough and could be used without any problems. The matrix effect which could change the equilibrium parameters in HS method was find negligible in many components. The actual samples such as tap water and river water were analyzed with both methods concerning 16 components regulated in Korea.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.2
• /
• pp.289-295
• /
• 2017

The International Maritime Organization (IMO) in accordance with the regulations with respect to the combustion gases, such as NOx, SOx generated by the marine engine. The combustion gases must be equipped with a device to reduce emissions from all ships passing through the Baltic SECAs. In Korea, the International Maritime Organization (IMO) and the development of a device for NOx, SOx reduction. Scrubber is used in the ammonia water and the Urea solution in the waste water. The waste water containing ammonium nitrate and ammonium sulfate, react of the NOx and SOx gas. In this study, the recovery of by-product, which contains the waste water was used as an organic solvent extraction method of salting out. Ammonium nitrate and ammonium sulfate, the recovery process. A qualitative analysis of the collected by-product FT-IR analysis. Through the elemental analysis and SEM-EDS, characteristic evaluation was performed with an impurity.

• Membrane Journal
• /
• v.27 no.3
• /
• pp.232-239
• /
• 2017

In this study, the regeneration investigation for waste reverse osmosis membrane filters which were discarded after use for the household water purifiers has been carried out. Sodium hydroxide, sodium bisulfate, and ethylenediamine tetra acetic acid(EDTA). as the chemical cleaning agents were used. And they were in-situ cleaned with the micro-bubble generator as well. The best result was obtained when both 0.1% EDTA and micro-bubbles were used for 30 min cleaning. Thus, when the performance of the brand new RO membrane and restorated RO membrane were compared, the flux, 19.9%, the recovery ratio 45% were enhanced while the salt rejection was reduced for NaCl 100 mg/L solution, in other words, it has been recovered to the original brand new RO membrane filter. Also the removal of pollutants on membrane surface was confirmed in a naked eye through the scanning electron microscopy. Finally, this research has provided the possibility of the re-use of the waste RO membrane filters of household water purifier which were reclaimed or incinerated after use.

• Journal of Korean Society on Water Environment
• /
• v.24 no.2
• /
• pp.201-205
• /
• 2008

The korean government started to ban the sanitary landfill of food wastes as of 2005. The radical change of policy is primarily due to the limited landfill site, but aimed to promote not only to reduce the food waste production but also to enhance the reuse and recycle. The performance of elutriated acid fermentation to evaluate the effects of elutriating ratios was investigated. The fermenters were operated with elutriating water to food waste volumetric ratio of 2, 1, 0.5 and 0.25. Initial pH of elutriating water was set for 9 based on the pH effects study. The cumulative amounts of SCOD production rate were $0.34gSCOD/gVS_i$, $0.45gSCOD/gVS_i$, $0.26gSCOD/gVS_i$ and $0.28gSCOD/gVS_i$ with the ratios of 2, 1, 0.5 and 0.25, respectively. The cumulative productions of VFAs were 0.12 gVFAs as $COD/gVS_i$, 0.28 gVFAs as $COD/gVS_i$, 0.21 gVFAs as $COD/gVS_i$ and 0.14 gVFAs as $COD/gVS_i$ with the ratios of 2, 1, 0.5 and 0.25, respectively. The volume reduction were 58%, 52%, 45% and 47% with the ratios of 2, 1, 0.5 and 0.25, respectively.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.7
• /
• pp.924-930
• /
• 2010

Ileal and total tract digestibility and nitrogen (N) balance of diets with four different protein sources were determined in growing pigs. The diets were based on rice bran, broken rice and maize meal and contained Tra catfish by-product (CBP), processed using three different methods, and marine fish meal (FM). The CBP diets consisted of the by-product in meal form, ensiled with molasses, and CBP waste water (WWBD). The four diets were fed to four growing pigs fitted with post-valve T-cecum (PVTC) cannulas in a $4{\times}4$ Latin Square design. All experimental diets included $Cr_2O_3$ at 5 g/kg feed as an indigestible marker. The ileal apparent digestibility of organic matter and ether extract was higher on diet WWBD than on the other three diets (p<0.05), and the total tract apparent digestibility was higher on diet WWBD than on the FM diet (p<0.05). The ileal and total tract apparent digestibility of crude protein and amino acids was not significantly different among diets (p>0.05). No significant effects of diet were found on N-retention and N utilization. In conclusion, the catfish by-product meal, ensiled catfish by-product and processing waste water diets and the fish meal diet had similar ileal and total tract apparent digestibility, and similar N utilization in growing pigs.

• Resources Recycling
• /
• v.20 no.5
• /
• pp.64-68
• /
• 2011

The typical properties of manganese nodules are its high porosity and high specific surface area and manganese in nodules is existed as ${\delta}$-MnO$_2$. These properties suggest that manganese nodules ran be used as an adsorbent for heavy metal ions. This study investigated the practical applicability for the removal of copper ions in the waste water by manganese nodules as an adsorbent using fixed column and fix bed systems. Manganese nodules of 1kg (size 1-3 cm) can absorb 4.0g Cu in fixed column system and 2.3g Cu in fixed bed system from waste water for 3 hours respectively.

• Membrane and Water Treatment
• /
• v.8 no.3
• /
• pp.279-292
• /
• 2017

This study was aimed at ultrafiltration (UF) as a pretreatment before reverse osmosis (RO) within the scheme of hybrid reverse osmosis-multistage flush (RO-MSF) desalination. Seawater at elevated temperature (after MSF heat-exchangers) was used as a feed in this process. The pretreatment system was represented as a set of functionally-linked technological segments such as: UF filtration, backwashing, chemical- enhanced backwashing, cleaning, waste disposal, etc. The process represents the sequences of operating cycles. The cycle, in turn, consists of the following unit operations: filtration, backwashing and chemical-enhanced backwashing (CEB). Quantitative assessment was based on the following indicators: normalized permeability, transmembrane pressure, specific energy and water consumption, specific waste generation. UF pre-treatment is accompanied by the following waste streams: $W1=1.19{\times}10$ power of $-2m^3$ (disposed NaOCl with 0.0044% wt.)/$m^3$ (filtrate); $W2=5.95{\times}10$ power of $-3m^3$ (disposed $H_2SO_4$ with 0.052% wt.)/$m^3$(filtrate); $W3=7.26{\times}10$ power of $-2m^3$ (disposed sea water)/$m^3$ (filtrate). Specific energy consumption is $1.11{\times}10$ power of $-1kWh/m^3$ (filtrate). The indicators evaluated over the cycles with conventional (non-chemical) backwashing were compared with the cycles accompanied by CEB. A positive impact of CEB on performance indicators was demonstrated namely: normalized UF resistance remains unchanged within the regime accompanied by CEB, whereas the lack of CEB results in 30% of its growth. Those quantitative indicators can be incorporated into the target function for solving different optimization problems. They can be used in the software for optimisation of operating regimes or in the synthesis of optimal flow- diagram. The cycle characteristics, process parameters and water quality data are attached.

• Journal of environmental and Sanitary engineering
• /
• v.15 no.2
• /
• pp.34-40
• /
• 2000

In the tungsten industry, molybdenum wire which used as the center supporter for coil shape tungsten wire was removed. Nitric acid dissolution method which used prevalently up to the present, takes nitric acid as major component and use noxious material such as sulfuric acid and hydrochloric acid remove molybdenum wire which used as center supporter by dissolve selectively within the range of no damage on tungsten wire. Mixed acid waste water occurred to the process were difficult to be decomposed by the conventional methords. This mixed acid waste water was treated by ozone, and It was obtained using possible by-product through the treatment waste water. For the three reactors with the same volume ; Blank reactor, Disturbance plate reactor, Packed-bed reactor ; the results were as follows : For the blank reactor COD removal efficiency in the pH = 4 (HRT : 6hr) was 28.5%, COD removal efficiency in the pH = 7 (HRT : 6hr) was 28.6%, and COD removal efficiency in the pH = 10 (HRT : 6hr) was 27.8%. For the disturbance plate reactor COD removal efficiency in the pH = 4 (HRT : 6Min.) was 86.5%, COD removal efficiency in the pH =7 (HRT : 6Min.) was 84.4%, and COD removal efficiency in the pH = 10 (HRT : 60Min.) was 86.8%. For the packed-bed reactor COD removal efficiency in the pH = 4 (HRT : 40Min.) was 76.0%, COD removal efficiency in the pH = 7 (HRT : 40Min.) was 81.3%, and COD removal efficiency in the pH = 10 (HRT : 40Min.) was 84.6%. After O3 treatment using possible by-product(Na2SO4) was 150g/ℓ.

• Journal of Animal Environmental Science
• /
• v.19 no.1
• /
• pp.39-46
• /
• 2013

This study was carried out to compare the filtration effect of anaerobic digestion waste water by compost filtration bed. Three types of filtration systems were set for filtration test following to composition of bedding materials. Two filtration systems were filled with sawdust, rice-hull and wood-chip. And the other was filled with sawdust and rice-hull. Anaerobic digestion waste water was applied evenly on the surface of the filtration bed with spraying nozzle. The concentration of nitrogen, biochemical oxygen demand (BOD), suspended solids (SS) of anaerobic digestion waste water was decreased by filtration treatment. The total nitrogen content was decreased from 1,313 mg/L to 1,090~1,293 mg/L and BOD concentration was decreased from 529.7 mg/L to 125~162.3 mg/L, respectively. The SS content was decreased from 69~79% by filtration process. In addition, the electrical conductivity (EC) was decreased from 10.22 ds/m to 7.91~8.31 ds/m.