• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.3
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• pp.256-267
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• 2019

Styrofoam beads, which are relatively inexpensive and can provide a large specific surface area, were tested as filter media. Styrofoam beads with a diameter of $3{\pm}0.5mm$ were used; the specific surface area of the beads was $1,034m^2{\cdot}m^{-3}$. Five independent recirculating culture systems were used in the experiment. Each system consisted of one culture tank and three trickling bio-filters. Using the systems, nitrification efficiency was evaluated with respect to hydraulic loading rate (HLR) and carbon/nitrogen (C/N) ratio. The lowest ammonia and nitrogen concentrations were $0.84mg{\cdot}L^{-1}$ and $1.30mg{\cdot}L^{-1}$, respectively, observed at an HLR of $50.9m^3{\cdot}m^{-2}{\cdot}h^{-1}$. Nitrification efficiency in the culture tank was highest at a C/N ratio of 0, with ammonia and nitrite nitrogen concentrations of $0.32mg{\cdot}L^{-1}$ and $0.90mg{\cdot}L^{-1}$, respectively. Ammonia and nitrite nitrogen concentrations in the culture tank abruptly changed at C/N ratios ${\geq}3$.

• Journal of the Korean GEO-environmental Society
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• v.3 no.2
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• pp.61-70
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• 2002

This paper presents the engineering property of light weight soil made of soil mixed with recycled Styrofoam and stabilizer. Recycled Styrofoam is widely used for lightweight fill material because it has important geotechnical characteristics which are light, adiabatic, and effective for vibration interception. It is very easy to get the disposal styrofoam. For this study, dynamic compaction test, static compaction test and pH and leaching tests were performed. Based on the test results, it is concluded that the static compaction method is recommened to prevent from crushing materials and pH values of embankment materials are satisfied with these of domestic and RCRA configuration.

• Ocean and Polar Research
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• v.25 no.3
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• pp.277-286
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• 2003

Nitrification performance of fixed film biofilters using coarse sand, loess bead, or styrofoam beads in biofilter columns 1 meter high and 30cm in diameter were studied at different hydraulic and organic matter loading rates. Synthetic wastewater was supplied to the culture tank in order to maintain desired TAN concentrations in inlet water to biofilters. All the biofilters were conditioned 5 months before start of sampling. TAN and $NO_2-N$ conversion rates increased with an increase in the hydraulic loading rate (HLR). However, the improvement in biofilter performance was not linearly correlated to HLR in styrofoam bead filters. This is mainly due to the characteristics of the styrofoam beads used. TAN conversion rates of sand filters increased with the increase of HLR up to $200m^3/m^2$. per day. No increase in the TAN conversion rate was observed at the highest HLR since flooding on the media surface took place. HLR had a significant impact on the TAN conversion rates in loess bead filter up to the highest HLR tested (P<0.05). TAN conversion rates were much less at organic matter loading rates of 9 and 18kg $O_2/m^3$ per day than those without the addition of organic matter in styrofoam bead filters. The addition of glucose resulted in a reduction of the TAN conversion rate from 540 to 284g $TAN/m^3$ per day. No significant difference of TAN conversion rates between the two organic matter loading rates was found (p<0.05). This indicates that the impact of organic matter on nitrification becomes less and less sensitive with an increase in the COD/TAN ratio. At an organic matter loading rate of 9kg $O_2/m^3$. per day, a great reduction of TAN conversion rates was observed in sand filters and loess bead filters. Clearly, organic matter can be one of the most Important Impacting factors on nitrification. $NO_2-N$ conversion rates showed a similar trend for TAN. Based on the TAN and nitrite conversion rates, styrofoam beads showed the best performance among the three filter media tested. Also, the low gravity and price of styrofoam beads make the handling easier and more cost-effective for commercial application. The results obtained at the highest organic matter loading rates can be used in the biofilter design in recirculating aquaculture system.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.281-283
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• 2001

The low foamed high strengthen styrofoam samples made by dielectric heating are discussed. We used the oscillator which have the frequency of 13.6MHz and the Power of 7kW. 3 times expanded beads by steaming method were used in our foam-molding test. Internal fusion properties and density of internal structure were improved by dielectric foaming process. At the temperature of 105-110$^{\circ}C$, the internal fusion property was maximally improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.94-103
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• 2005

The low foamed high strengthen styrofoam samples made by dielectric heating are discussed. We used the oscillator which have the frequency of 13.6 MHz and the power of 7 kW. 3 times expanded beads by steaming method were used in our foam-molding test. Internal fusion properties and density of internal structure were improved by dielectric foaming process. At the temperature of $105-110^{\circ}C$, the internal fusion property was maximally improved.

• Journal of the Korean GEO-environmental Society
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• v.7 no.5
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• pp.21-29
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• 2006

Light weight filling method prevents settlement of ground by decreasing the weight of fills. This method is increasingly used for it's convenience and workability. Styrofoam is increasingly used as a lightweight filling material in soft ground. The beneficial effects of the use of EPS derive from minimizing the stress increment, increasing the bearing capacity and reducing the settlement. For this study, model test and FEM analysis of bearing capacity is carried out composing two-layered ground with clay in the lower layer and lightweight filling material in upper layer. Based on the results obtained here in this study, it is concluded that the use of recycled EPS beads is acceptable lightweight fill. Light weight fills used for disposal is superior to typical embankment fills in bearing capacity.