김도형 Do Hyeong Kim , 정병곤 Byung Gon Jeong

DOI:10.9786/kswm.2019.36.5.413

Abstract

The optimization of the manufacturing process of liquid clipped-grass fertilizer using Paenibacillus ehimensis KWN38 was studied using a laboratory scale reactor. It may be concluded that favorable conditions may be obtained by maintaining oxic conditions through aeration when assessing the performance of the process. When comparing among sterilization methods as a pretreatment, high pressure steam sterilization was a more efficient method than the ozone treatment. From our experiment examining the effect of increasing the aeration rate, it may be concluded that the optimum aeration rate is 0.4 ~ 0.8 L/min·L air. We conclude that the optimum dosage of microorganisms is 1 mL per L of composite liquid clippedgrass fertilizer. The optimum decay period is 10 days at an operating temperature of 20℃ and 5 days at an operating temperature of 30℃. Improved performance in making liquid clipped-grass fertilizer can be obtained at an operating temperature of 30℃ rather than 20℃. The ORP may be applied as an operational control parameter instead of the C/N ratio due to the strong correlation between the C/N ratio and the ORP operational control parameter. It should be noted that aeration should be stopped temporarily before measuring the ORP. The concentration of heavy metals in the manufactured liquid clipped-grass fertilizer was less than the standards guideline.

Key Words

Aeration rate, C/N ratio, Liquid clipped-grass fertilizer, Paenibacillus ehimensis KWN38, Turfgrass clippings

박영성 Yeong-seong Park , 이재열 Jae-yo’l Lee , 손무정 Moo-jeong Sohn

DOI:10.9786/kswm.2019.36.5.421

Abstract

The regeneration characteristics of the waste adsorbent made by drinking water treatment sludge were investigated. Regeneration of the waste adsorbent was accomplished by steam activation. For analyses of the adsorbent samples, various methods were adopted, such as scanning electron microscopy (SEM), measurement of BET surface area, and chemical composition analyses. To assess a major adsorption characteristic, the adsorption equilibrium capacity was measured using a batch type experimental apparatus. The experimental results showed that the H2S adsorption equilibrium capacity of the regenerated adsorbent increased with activation temperature in the range of 400 ~ 600℃. The regeneration efficiency of the waste adsorbent was 80 ~ 100% across the all experimental conditions, and the temperature range suitable for regenerating the waste adsorbent was found to be 500 ~ 600℃.

Key Words

Waste adsorbent, Steam activation, H₂S, Equilibrium capacity

김도완 Do-hwan Kim , 임병란 Byung-ran Lim , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2019.36.5.428

Abstract

A Circulation Resource Certification System was enforced and the foreign substance matter standard of metal scrap decreased to within 2%. In the case of this TDS (Tire-Derived-Steel), depending on the type of recycling standard R-3- 3, foreign substances of 2% or more are contained and it is not suitable as a raw material because it contains foreign substances that are impossible to use. TDS, which can be recycled as a raw material for steelmaking products, cannot be a recycled resource based on foreign material criteria but is instead regarded as waste, and is as a result not circulated. Therefore, in this research, we mainly compare TDS and the validity of the standard of metallic foreign substance waste in the recycling resource certification system to the TDS foreign substances relation standard by measuring the characteristics of TDS and the content of foreign material. Among the certification criteria, I discuss a problem related to iron scrap standards and propose remedial measures.

Key Words

Recycle, Circulation resource certification, TDS, Foreign substances

김도완 Do-hwan Kim , 임병란 Byung-ran Lim , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2019.36.5.435

Abstract

Recently, the quality standards in the process of producing solid fuel and energy recycling of waste tire were exceeded. We examined the content of sulfur and Proximate compared to the quality standards of TDF (Tire-Derived-Fuel) in domestic and foreign waste tires. As a result of a Proximate Analysis of the tires, the parts (tread, side wall, and bead), the content of ash in the tread parts of the tire exceeded 20%. In addition, the content of sulfur was observed to exceed 2% in some domestic tires. As a result of analyzing tires exceeding the quality standards, the cause of the excess seems to be caused by an increase in the ratio of vulcanizing agent and inorganic filler added to produce high-performance tires. Therefore, in this study, we propose that the waste tires be separated and that the sulfur and ash contents are discharged preliminarily and recycled by a method other than TDF.

Key Words

SRF, TDF, Waste Tire, Sulfur contents, Quality standard

이수영 Su Yeong Lee , 박만호 Man Ho Park , 김재영 Jae Young Kim

DOI:10.9786/kswm.2019.36.5.444

Abstract

Food waste disposers are convenient devices with which to throw away food waste from households by grinding the disposed scraps. However, the use of disposers has been limited due to barriers such as sewer blockages and load increases to wastewater treatment facilities. Woodchips can be an effective and economical filter material with which to recover solid and aqueous-phase contaminants, considering their particle sizes and surface characteristics. In this study, the performance of woodchips in treating disposer wastewater was examined. Characterization studies using scanned electron microscopy (SEM), elemental analysis, and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis were performed to identify changes in packing materials during filtration. The effects of packing density and the effective particle size of the packing materials on solid recovery were assessed using filtering tests. According to the results, the maximum solid recovery rate was 83% (by weight) and packing density, rather than effective particle size, was the significant parameter determining filter performance. Packing densities up to approximately 0.9 g/cm³ led to increased solid recovery rates, while packing densities greater than 0.9 g/cm³ led to lower solid recovery. After filtering through woodchips, the reductions of dissolved chemical oxygen demand (COD) and total nitrogen (T-N) were confirmed. Woodchips were not effective in removing aqueous phosphorus. The batch adsorption test showed that woodchips have an adsorption capacity for T-N but not for COD and total phosphorus (T-P). According to the characterization studies, the recovery mechanisms by the woodchip filter were surface filtration, straining, and adsorption.

Key Words

Disposer wastewater, Filtration, Solid recovery, Woodchip filter

김용준 Yong-jun Kim , 엄남일 Nam-il Uhm , 김우일 Woo-il Kim , 김정대 Joung-dea Kim , 이영기 Young-kee Lee , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2019.36.5.452

Abstract

The purpose of this study was to investigate the pH reduction time and the rate of the aging process of ash from the paper industry. In addition, we evaluated the environmental stability of the aging process by confirming the leaching characteristics of heavy metals according to pH changes. Our results indicated that the heavy metal contents of ash from the paper industry were ranked (in descending order): Cu > Pb > T-Cr > Cd > As > Cr⁶⁺ > Hg. It was confirmed that the ash was contained at a high pH of approximately 12 at the beginning of the discharge due to a high amount of the CaO component, but the pH was confirmed to be approximately 8 by reacting with atmospheric CO₂ through the aging process. We also confirmed that the amount of heavy metal leaching decreased as the pH was reduced throughout the aging process of the ash produced by the paper industry. Therefore, we suggest that recycling the ashes discharged from the paper industry can utilize aging as a method of reducing the pH and the leaching of heavy metals.

Key Words

Paper industry, Ash, Heavy matals, Aging

천승규 Seung-kyu Chun , 심낙종 Nakjong Sim , 전은정 Eunjeong Jeon , 윤수경 Suekyoung Yun , 박정현 Junghyun Park

DOI:10.9786/kswm.2019.36.5.460

Abstract

The organic carbon contents of excavated waste samples were analyzed for the evaluation and forecasting of the stabilization state and aftercare period of the first landfill of the Sudokwon Landfill Site. The total disposed matter was 83.1 × 10⁶ Mg (56.5 × 10⁶ Mg on a dry basis), of which organic carbon was 6.4 × 10⁶ Mg (a content ratio of 11.3%). Coarse incombustibles, vinyl, and mixed organic matter had weight ratios of 7.8%, 16.6%, and 75.7% respectively, with a total average moisture content of 37.1%. The average organic carbon content ratio was 5.1%, with 45.1% remaining compared to the disposed of amount. As almost all of the biochemically degradable carbon was emitted, satisfying landfill stabilization criteria for organic matter content is challenging under current landfill management practices.

Key Words

Landfill stabilization, Post management, Organic carbon, Three component analysis, Element analysis

최자형 Ja-hyung Choi , 오세천 Sea Cheon Oh

DOI:10.9786/kswm.2019.36.5.471

Abstract

Recently, interest in the recycling of municipal solid waste ash has greatly increased as desires have rose to minimize landfill waste. However, recycling of fly ash from municipal solid waste is almost impossible due to its high chlorine content. Therefore, the possibility of chlorine removal from fly ash using acid and alkaline solutions has been studied in this work. Sulfuric acid, nitric acid, and sodium hydroxide solutions were used as acid and alkaline solutions. From this work it was found in all cases that the removal of chlorine increased with increasing acid and base concentrations. Chlorine removal also increased by increasing the reaction temperature for a sulfuric acid solution, but the optimal reaction temperature was needed to maximize chlorine removal in the case of a nitric acid solution. It was also found that sulfuric acid solutions were more effective than nitric acid and sodium hydroxide solutions for the removal of chlorine from fly ash.

Key Words

Incineration, Fly ash, Chlorine, Acid solution, Alkaline solution

장성호 Seong-ho Jang , 강정희 Jeong-hee Kang , 김고은 Go-eun Kim , 홍성철 Sung-chul Hong , 이병인 Pyong-in Yi , 서정민 Jeong-min Suh , 정은상 Eun-sang Jung , 박제성 Je-sung Park , 박진식 Jin-sick Park , 이재용 Jae-yong Lee

DOI:10.9786/kswm.2019.36.5.480

Abstract

In this study, the effects of current density and electrolyte on total nitrogen (T-N) removal efficiency for dyeing wastewater treatment were tested with stainless steel electrodes. Without electrolyte and when the current density was adjusted to 20, 40, and 60 A/m², the removal efficiency of T-N was 39.1%, 55.6%, and 72.4% at 60 min, respectively. However, at all current densities, the removal efficiency with NaCl (10 mM) was 21.0% higher on average and with Na₂SO₄ (10 mM) was 5.3% higher on average.

Key Words

Electrolyte, Dyeing wastewater, T-N, STS316

윤상혁 Sang Hyuck Yoon , 전찬수 Chan-soo Jeon , 이세현 Sea-hyun Lee

DOI:10.9786/kswm.2019.36.5.487

Abstract

The density increased to 6.3% on average after passing through the ascending blowing and impact inducing rotating device, and the absorption rate decreased to 38.1% on average after passing through before the passing. In addition, the test results for grain size, the amount lost in the 0.08-mm sieve, clay lump levels, and safety were all excellent after passing through the rotor hammer and multistage wind pressure treating apparatus. Organic matter was also reduced to an average of 69.2% after passage, and the inorganic matter decreased to 29.6%. All of these results satisfied KS F 2527 standards, meaning it can be used as recycled coarse aggregate for concrete.

Key Words

Vertical, Spreader, Impact, Recycled coarse aggregate, Density, Percentage of absorption