• Journal of Environmental Health Sciences
• /
• v.21 no.4
• /
• pp.17-23
• /
• 1995

As a basic experiment to develope biological pretreatment proces~ in water treatment, the experiments on biodegradability and isothermal adsorption of activated carbon were performed on refractories such as humic acid, $NH_3-N$, phenol and ABS which caused the problems in drinking water treatment. Also, the treatabilities on humic acid were examined in the continuous flow type reactors. The removal efficiencies of humic acid, $NH_3-N$, phenol and ABS in the biodegradable experiments for 5 days were 20.1%, 73.4%, 91.7% and 97.5%, respectively. In the isothermal adsorption test of refractories on activated carbon to be used as a media in the continuous flow type reactors, ABS and phenol are adsorbed easily, but humic acid and $NH_3-N$ are difficult to be done. The removal efficiencies of humic acid in granular activated carbon(GAC) reactor were about 7-8% higher than in biological activated carbon(BAC) reactor. The removal efficiencies of humic acid in biological fluidized bed(BFB) reactor were about 30% in GAC media, but were almost zero in sea sand media.

• Journal of Bio-Environment Control
• /
• v.16 no.1
• /
• pp.62-66
• /
• 2007

This study was carried out to develop the stable plug seedling production for hydroponics of spinaches by various nursery media, plug tray size and seed number per plug tray cell. When plant grown in various nursery media, the seeding stand rate was shown in order of granular rockwool with good water retention, granular rockwool>granular rockwool mixed with pearlite>cocopeat>pearlite>poly urethane foame. Thus, poly urethane foame indicated the lower seedling stand rate. There was no difference in growth of the seedlings md the seeding stand rate by the plug tray size, and no significant difference in the plant height and the number of leaves among the seed number per plug tray cell. But, leaf area of plant in 2 grains seeding per cell was $113.0cm^2$, was wider in compared with 5 grains seeding of which leaf area was $88.0cm^2$. Accordingly, the leaf area per plant decreased as more and more the number of seeds per plug tray cell increased. The fresh weight of a plant per plug tray cell was the heaviest with 12.5g in the 2 grains, and the total fresh weight of plants per cell was 33.9g in 4 grains seeding, thus it tended to was bigger compared with other treatments. Consequently, given that the number of seeds per cell was decreased, the fresh weight of a plant increased. On the other hand, the total fresh weight per cell showed a tendency to be reducing as more and more the number of seeds per plug tray cell decreased. The yield in the 4 grains seeding was increased by 46% as $14,910kg{\cdot}ha^{-1}$ in compared with the yield in 2 grains seeding as $10,200kg{\cdot}ha^{-1}$.

• Journal of Korean Society of Water and Wastewater
• /
• v.22 no.6
• /
• pp.697-704
• /
• 2008

Stormwater runoff from urban road area as non-point source has a tendency of including lots of pollutants at initial rain period. Recently, there are several cases of having installed treatment facilities for reducing pollution discharge from the impervious cover in urban area to prevent watershed environment from getting worse. The filtration type among non-point source treatment systems has been known as one of the most efficient system for treatment of non-point source pollutants. Therefore, various kinds of filter media such as expanded polypropylene(EPP), granular activated carbon, zeolite, perlite, illite, sand, gravel has been developed. This study was conducted to verify performance and hydraulic characteristics of filter media as measures for non-point source. The experiment was carried out to evaluate applicability and variation of 4 kind of most popular filter media(EPP, GAC, Zeolite, Perlite) in headloss with elapsed time and influent flow rate and to obtain data base that could be used to establish management plan for road runoff treatment. In experiment by tap water, it showed that EPP and perlite those are floatable materials showed stable operating performance and lower headloss than the others.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.3
• /
• pp.61-72
• /
• 1999

To obtain the experimental data for design and operation of actual filtration processes, a sand filter and three kinds of dual media filters in pilot-plant scale were operated in this study. We analyzed the effect of filter medium composition on the filter performance and the effects of backwash water flow rates, length of stream line and air flow rate on the filter backwash efficiency. We also compared the efficiencies of the combined air-water backwashing and the water backwashing in dual media filters. As the backwash water flow rates or the length of stream line increased, the final turbidity of backwash water was decreased and the filtration duration time after backwash was increased. In the case of the combined air-water backwashing, the backwash water quantity needed for backwashing the dual media filters could be decreased. The total volume of filtered water for the dual media filters during filter run was over three times larger than that for the sand filter. The dual media filters could be operated at a high filtration rate of 360 m/day.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.3
• /
• pp.265-276
• /
• 2007

The primary objective of this study is to investigate the effect of media on the performance of biofilters. Two types of experiments were carried out in this study. The first type of experiment used a biofilter with the media composed of three different packing materials of compost, peatmoss and GAC(granular activated carbon), whereas the second type used a biofilter with the media composed of compost only. It was found from the two experiments that the biofilter composed of compost, peatmoss and GAC showed better performance than the one composed of compost only with the higher toluene removal efficiency, lower pressure drop, and more uniform media moisture content. In particular, no appreciable media compression occurred for the biofilter composed of compost, peatmoss and GAC, whereas significant media compression took place in the biofilter composed of compost only. As suggested by the other researchers, it is likely that GAC may be responsible for the higher toluene removal efficiency in the case of the biofilter composed of mixed media especially for the early stage of biofiltration due to its adsorption capability of toluene of such high concentration as 300 ppm. It was also regarded that GAC may playa major role in maintaining lower media pressure drop in the case of the mixed media than the media with compost only because of its mechanical strength resisting to the compression. Nonetheless, further refined experiments may need to draw more accurate conclusion. The results of the additional test run using the same mixed media showed that the biofilter system using the mixed media can be consistently operated for more than 100 days very stably despite sudden change in operating conditions of temperature and flow rate.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2008.12a
• /
• pp.125.2-125.2
• /
• 2008

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.673-679
• /
• 2004

Particle breakthrough can occur by either the breakoff of previously captured particles (or flocs) or the direct passage of some influent particles through the filter. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5, nearly pure $SiO_2$) and three different destabilization methods (pH control, alum and polymer destabilization) were utilized. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. To assess the possibility of particle detachment during the normal filtration, a hydraulic shock load (20% increase of flow rate) was applied after 4 hours of normal filtration. The magnitude of particle detachment was proportional to the particle size for non-Brownian particles. At the same time, less favorable particles, i.e., particles with larger surface charge, were easily detached during the hydraulic shock load. Therefore, proper particle destabilization before filtration is crucial for maximum particle removal as well as minimum particle breakthrough.

• Environmental Engineering Research
• /
• v.20 no.3
• /
• pp.230-236
• /
• 2015

26 multi-regional water treatment plants (WTPs) were investigated, to determine the characteristics of manganese (Mn) concentration and removal in Korea. Mn concentrations of raw water in most WTPs were higher than the drinking water standard (i.e., 0.05 mg/L); thus, proper removal of Mn at the WTPs is needed. Mn concentration was generally higher in lakes than rivers due to seasonal lake turnovers. The Mn concentrations of treated water at 26 WTPs in 2012 were less than 0.05 mg/L, due to strict law enforcement and water treatment processes optimization. However, before 2010, those concentrations were more than 0.05 mg/L, which could have led to an accumulation of Mn oxides in the distribution system. This could be one of the main reasons for black water occurrence. Therefore, regular monitoring of Mn concentration in the distribution system, flushing, and proper Mn removal at WTPs are needed, to supply clean and palatable tap water.

• Journal of the Korean Geotechnical Society
• /
• v.26 no.4
• /
• pp.37-45
• /
• 2010

Salt cementation, a typical naturally-cemented phenomenon, may occur due to water evaporation under the change of climate. Capillary force may influence the distribution of cement in granular soils. This study addresses the effect of capillary force on salt cementation using five different techniques: cone penetration test, electrical conductivity measurement, photographic imaging technique, nondestructive imaging technique, and process monitoring by elastic wave. Glass beads modeling a particulate media was mixed with salt water and then dried in an oven to create the cementation condition. Experimental results show that salt cementation highly concentrates at the top of the small particle size specimens and at the middle or the bottom of the large particle specimens. The predicted capillary heights are similar to the locations of high salt concentration in the cemented specimens. Five suggested methods show that the behavior of salt-cemented granular media heavily depends on the capillary force.

• Journal of Soil and Groundwater Environment
• /
• v.13 no.3
• /
• pp.21-26
• /
• 2008

Nitrate adsorption from aqueous solutions onto zinc chloride ($ZnCl_2$) treated coconut Granular Activated Carbon (GAC) was studied in a batch mode at two different initial nitrate concentrations (25 and 50 mg/L). The rate of nitrate uptake on prepared media was fast in the beginning, and 50% of adsorption was occurred within 10 min. The adsorption equilibrium was achieved within one hour. The mechanism of adsorption of nitrate on $ZnCl_2$ treated coconut GAC was investigated using four simplified kinetic models : the rate parameters were calculated for each model. The kinetic analysis indicated that pseudo-second-order kinetic with pore-diffusion-controlled was the best correlation of the experimental kinetic data in the present adsorption study.