• Journal of Convergence for Information Technology
• /
• v.7 no.1
• /
• pp.67-73
• /
• 2017

Paper sludge ash, blast furnace slag, fine powder quicklime, anhydrous gypsum, and fly ash as the main ingredients were prepared to suit the salty soils of marine soils. The solidification component is a kind of recycled ceramic, and CaO plays an important role in solidification. The neutralization time after solidification was about 2 weeks, and the compressive strength was about 12N/mm2 in the mortar test after one week incubation with standard yarn. This is about 14 times stronger than the solidifying agent used in the metropolitan area. As a result of applying plate load test to saltous marine soils, we obtained the yield load that can pass the large scale even after 5 days. In the uniaxial compressive strength test, shear strength of about 300 kPa was obtained after 5 days. It will be useful for supplementing the soft ground in the area where marine reclamation is much like the Incheon area.

• Journal of Environmental Impact Assessment
• /
• v.21 no.1
• /
• pp.63-69
• /
• 2012

Sediment has been increasingly acknowledged as a carrier in water system and an available contamination. For this reason, dredging of sediment in reservoir to remediate water quality and secure storage capacity is conducted annually. However, disposal of numerous dredged sediment is necessary as a secondary problem. Currently, in Korea, dredged sediment is classified as waste to be reclamated or recycled into sandy soil, however, they are still in trouble because of spacial and environmental problem. Therefore, rather than simple disposal or reuse into sandy soil, it is necessary to research on method to manage main cause of pollution and increase the value as a resource. In this study, we intend to develop a recycle technology for numerous dredged sediment produced by dredging in deteriorated reservoirs using solidificator (stabilizer). To achieve this, we will consider utilization of dredged sediment and evaluation of use possibility as natural recycle by analysis the characteristics of soil-solidificator mixture in terms of physicochemical properties and the mixing ratio between sediment and solidificator.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.488-494
• /
• 2012

This study was conducted to determine the optimal ratio of sludges from milk processing industry (MPS), paper-mill industry (PMS) and night-soil treatment plant (NSS) for vermicomposting. Five different ratios, 0 : 80 : 20 (MPS-0), 25 : 60 : 15 (MPS-25), 50 : 40 : 10 (MPS-50), 75 : 20 : 5 (MPS-75), and 100 : 0 : 0 (MPS-100 : control) MPS : PMS : NSS by wet weight were tested in a small plot experiment. The experiment for each mixing ratio was performed for 2 weeks with the three replications. MPS-100 (100 : 0 : 0) only had the highest decomposition rate with 19.9%, followed by MPS-25, MPS-50, MPS-75 and MPS-0 with 19.5, 19.1, 17.6 and 16.7%, respectively. Except for MPS-100, Vermicomposting resulted in increase in ash, T-P, $NO_2{^-}-N$, $NO_3{^-}-N$, Mg, K, As, Cd and Cu, whereas moisture, VS (Volatile Substance), TKN (Total Kjeldahl Nitrogen), $NH_4{^+}-N$, Ca, Hg and Pb were lower in the final cast than the initial feed mixture. Meanwhile Zn showed very slight difference and Cr and Ni did not show any tendency between the feed mixture and the final cast. In the case of MPS-100, where the decomposition rate was the highest, all the heavy metals in the final cast except for Hg were increased. All the vermicomposts produced from five different mixing ratios of the vermicomposting sludges met the Korea Standard as by-product compost.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.3
• /
• pp.49-55
• /
• 2012

In this paper, the physical properties of lightweight aggregate such as density and water absorption according to addition ratio and type of flux were investigated. When using $Na_2CO_3$ as flux of lightweight aggregate, burnability was available at low burning temperature and water absorption increased. And as increasing addition ratio of $CaCO_3$, NaOH, $Fe_2O_3$, absorption decreased and $CaCO_3$, NaOH, $Fe_2O_3$ were considered improper to use flux of lightweight aggregate because of high dried density. $Na_2SO_4$ was proper to use flux of lightweight aggregate due to dried density $1.35{\sim}1.50g/cm^3$ and lower absorption. When using glass abrasive sludge as flux of lightweight aggregate, dried density and water absorption were in the range of $1.45{\sim}1.55g/cm^3$ and 9~12% respectively. It was indicated that as increasing addition ratio of blast furnace slag powder, density increased whereas absorption decreased. In use of oxidizing slag as flux, artificial lightweight aggregate which have dried density $1.46g/cm^3$, water absorption 8,5 % can be manufactured at 10 % of addition ratio.