• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.299-307
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• 2011

This study was carried out to obtain the basic data for selecting the cultivatable bioenergy crops through application of solidified sewage sludge in reclaimed lands. The experimental plots consisted of the mixing with solidified sewage sludge plot (SS50), the covering with solidified sewage sludge plot (SS100), and the original reclaimed land plot (ORL) on reclaimed land for the intended landfill in Sudokwon Landfill Site Management Corporation (SLC). The growth of energy crops (Geodae-Uksae 1, Miscanthus sacchariflorus, and Phragmites australis) were investigated from May to October, 2010 in each experimental plot. The soil from ORL showed higher salinity with high contents of exchangeable $Na^+$ cation than that of SS50 and SS100. Soil properties on reclaimed land used in this study must be improved by increasing the buffering capacity of saline with the treatment of solidified sewage sludge due to the fact that the contents of organic matter (OM) in both of SS50 and SS100 were higher than that of the ORL. Thus the growth of energy crops cultivated in the solidified sewage sludge plots were better than in ORL. Geodae-Uksae 1 which showed an excellent adaptability on reclaimed land treated with the solidified sewage sludge has considerably higher biomass than those of other energy crops (M. sacchariflorus and P. australis). This study suggested that Geodae-Uksae 1 is the most suitable biomass feedstock crop for bioenergy productions, and the solidified sewage sludge may be possible to utilize as a soil cover materials for cultivation of bioenergy crops in reclaimed land.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.2
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• pp.66-73
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• 2003

To investigate the availability of solidified wastes as resource, wastewater sludge, waste gypsum and fly ash were mixed and the results with various mixing ratios are as follows. Compressive strength turned out to be increasing as the amount of waste gypsum increases, keeps longer curing inhibition, and higher forming Pressure under the conditions of waste gypsum/sludge ratio 0.31-0.45, and 0.9kg cement as 15% and 1.2kg cement as 20% of total amount. Solidified agent under the fly ash/sludge ratio 0.45, 0.6, compressive strength seemed to be higher than standard one which means solidified wastes with these conditions could be applicable in real life. These results inform that concentrations of the leachate $Cr^{+6}$, Cu, Zn, Cd, Pb solidified matrix, containing low concentration of heavy metal, were cured with/without enough time it still will cause adverse effect on nature environment and application of heavy metal sequester must be needed to reuse industrial wastes from incineration plant solidified matrix. Total cost price, when considering manufacturing capability of the facilities for resourcerizing as 18,000ton was presented 678,664,000 won, as it were, manufacturing cost price was 37,704 won per ton. The results as above has shown that it's possible to use the mixture of waste gypsum/sludge, fly ash/sludge, cement, additions, and solidification matter as substitute of materials like brick, block, interlocking which has proper compressive strength of KS L 5201 and KS F 4004.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.611-616
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• 2001

Increased quantities of sewage sludge coupled with stringent regulations make it important to develope alternatives for residuals management. The use of PARAFIX as a solidifying agent for sewage sludge was investigated by several tests. Basic physicochemical characteristics, strength, permeability, and leaching characteristics were examined. PARAFIX was found to be very effective in reducing permeability, increasing strength, and immobilizing heavy metals. Based on the tests, it Is ascertained that PARAFIX enhances the solidification of sewage sludge. Also sewage sludge solidified with PARAFIX may be used effectively for construction materials.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.278-285
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• 2008

This research was performed to evaluate the landfilling method of organic sludge from mix of pre-treated organic sludge (OS) and municipal solid waste(MSW). Organic sludges were dried, composted, and solidified as pre-treatment and the OS and MSW were mixed in ratios of 2 to 8 and 4 to 6. Approximately 1,800$\sim$2,500 L of landfill gas(LFG) was generated in the lysimeter with solidified-OS, which was higher than 1,150$\sim$1,650 L of the dried- and composted- ones. Maximum H$_2$S concentration was found in the following order : Composted-20(80 ppmv) > Composted-40(55 ppmv) > Dried-20(30 ppmv) > Dried-40 $\fallingdotseq$ Solidified-20 $\fallingdotseq$ Solidified-40 (20 ppmv). BOD$_5$ at initial leachate generation period was 38,000 mg/L for Composted-40, 28,000 mg/L for Dried-40, 26,000 mg/L for Dried-20, 21,000 mg/L for Composted-20 and Solidified-40, and Solidified-20 for 17,000 mg/L. In the final period of experiment, BOD$_5$ was low as 300$\sim$500 mg/L in the lysimeter with solidified-OS and MSW and showed 2,000$\sim$3,500 mg/L in dried- and composted- ones. As the results, landfilling by mix of solidified-OS and MSW was evaluated as the most appropriate method for biodegradable organics. Direct landfilling of OS is permitted for landfill site with CDM facility. Therefore, mixed landfilling of solidified-OS and MSW should be considered for much more LFG generation as methane.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.374-380
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• 2015

This study firstly provides basic data for selection of cultivatable bioenergy grass in barren reclaimed lands applied with solidified sewage sludge. The experimental plots consisted of a plot containing reclaimed land mixed with solidified sewage sludge (MSS 50), a plot covered by solidified sewage sludge (CSS 100), and an original reclaimed soil plot (ORS). The growth, biomass production of bioenergy grasses and soil chemical properties were investigated in each experimental plot for 5 years. The organic matter (OM) and total nitrogen (T-N) content in both MSS 50 and CSS 100 were considerably higher than those in ORS. In bioenergy grasses, M. sacchariflorus cv. Geodae 1 showed an excellent growth and adaptability on reclaimed land applied with solidified sewage sludge. The application of solidified sewage sludge may provided soil nutrition in the reclaimed land due to the fact that bioenergy crops grew better in soils applied with solidified sewage sludge than in untreated soils, and treated soils had higher OM and T-N content than untreated soils. This study suggests that M. sacchariflorus cv. Geodae 1 is the most suitable biomass feedstock crop for biomass production and that solidified sewage sludge may be used as a soil material for cultivation of bioenergy grass on reclaimed lands.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1396-1399
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• 2005

Gas permeability of the solidified sewage sludge needs to be characterized in order to use as a large-scale landfill cover material. Four different types of the samples were prepared for gas permeability experiments: (1) granite soil, (2) dried sewage sludge, (3) solidified sewage mixed with slag and (4) solidified sewage mixed with granite soils. The experimental instrumentation and measurement devices were newly designed and created to effectively evaluate gas permeability of the samples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.381-387
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• 2015

This study was firstly conducted to investigate changes of vegetation and soil characteristics in reclaimed land applied with solidified sewage sludge for the cultivation of bioenergy crops. Each vegetation survey site was approximately $15m{\times}3m$ on the inside of each experimental plot that consisted of 50% (A-1), 30% (A-2), 15% (A-3), and 5% (A-4) mixture of solidified sewage sludge, and original reclaimed soil (ORS). After the application of solidified sewage sludge, we monitored the changes of vegetation and soil properties for three years. In first year, soil pH, electrical conductivity (EC) and exchangeable $Ca^{2+}$ content was 9.4~10.8, $9.10{\sim}14.41\;dS\;m^{-1}$, and $62.1{\sim}204.2\;cmol\;kg^{-1}$, respectively, while three years later, it decreased to 8.1~8.4, $1.65{\sim}5.98\;dS\;m^{-1}$, and $21.9{\sim}43.1\;cmol\;kg^{-1}$, respectively. These results indicated that several of soil chemical elements which have nagative impacts on the plant growth in the plots of mixtures of solidified sewage sludge, steadily declined as the years go by. The vegetations in each survey site were recorded as 6 families and 12 species in 2014, while the vegetations were not occurred at all survey sites in 2012, and only halophytes as Phragmites australis and Suaeda asparagoides were observed in 2013. Diversity of vegetation, which was calculated by shannon index (H'), increased as the season progressed at each experimental plot applied with solidified sewage sludge. In original reclaimed soil, however, there was showed the high community similarity of vegetation due to the fact that P. australis and S. asparagoides were only occurred for survey periods.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.21-30
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• 2002

This study was Performed to evaluate the effective solidification of Cd sludge using cement and power plant fly ash as cement admixture, to identify the leaching characteristics of the heavy metal Cd sludge solidified, and to develope proper KLT(Korean Leaching Test) of hazardous waste. KLT was compared with EPT(Extraction Procedure Toxicity) and TCLP(Toxicity Characteristics Leaching Procedure). Fly ash contents ranged from 0% to 30% of cement weight. The experimental results showed that the optimum amount of fly ash replaced was 10% to 15% and KLT was less appropriate than EPA and TCLP. Also the purpose of the study was to suggest the modification factors on the leaching test currently used, based on the above mentioned aspects. The effects of pH, leaching time, leaching for agitating intensity, and leaching solvent were investigated. As the result of test, the leaching potential was relatively high when the pH and agitation intensity of leaching solution were 5 and 150rpm, respectively. Leaching time of six hours was found to be sufficient and the use of acetic acid as a leaching solvent is more useful in landfill site particularly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.89-98
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• 1988

This research evaluated factors on cement-based solidification process designed for hazardous sludge produced from electroplating industry. Four factors of sand/cement ratio, water/cement ratio, amount of wet sludge and amount of a precipitator, were investigated in terms of leachability and compressive strength of the solidified materials. Results of triplicate tests and statistical analysis indicated that sand/cement ratio(S/C) had the greatest effect on leaching of Cr(VI) from the solidified materials while water/cement ratio(W/C) on Zn and compressive strength. Cr(VI) was fixed better than Zn by portland cement. An experimental modeing was developed to estimate leached metal concentration and compressive strength at a given condition. Proper mixing criteria were also suggested for the use of the solidified mixture as construction materials. In solidification of 30g dry sludge, optimal condition was studied for S/C ratio, W/C ratio and the weight of precipitator which were 1, 1.5 and 1.075g respectively.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.812-820
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• 2011

This study was conducted to characterize $CO_2$ biomineralization on several minerals (i.e., CaO, MgO, $SiO_2$) by bottle test in an aqueous solution and solidified sludge using different aerobic bacterial strains like Bacillus megaterium and Bacillus pasteurii by batch test. These bacteria promote the formation of microenvironments that facilitate the precipitation of mineral phases that were unsaturated in the bulk solution. For one type of mineral solely amended, the $CO_2$ was reduced at the highest of 4.0 mmol for MgO while it was not that much lower for CaO and $SiO_2$ showing 1.1 and 0.3 mmol $CO_2$2, respectively. For two types of minerals simultaneously amended, the $CO_2$ was reduced at the greater extent for both Ca + Mg and Mg + Si showing 2.7 and 2.3 mmol, respectively whereas it was less for Ca + Si at 1.8 mmol. For solidified sludge, the $CO_2$ reduction rate changed depending on the volume of solidified sludge placed in the medium and the input $CO_2$ concentration.. The reduction rate of $CO_2$ was increased with increasing the volume of solidified sludge. Results of XRD analysis indicate that $CaCO_3$ (Calcite) was dominantly formed among others (e.g., Aragonite, Dolomite). SEM analysis showed that the sample with Bacillus pasteurii, could more form minerals rather than control. As demonstrated in this study, $CO_2$ would be effectively sequestered in biomineralization process.