Low- and intermediate-level radioactive waste for permanent disposal often contains organic complexing agents, so-called chelating agents. Organic complexing agents, which are polycarboxylic acids, can increase the mobility of radionuclides into the environment by forming water-soluble complexes with most heavy metals. Therefore, analyzing the complexing agents in radioactive waste is crucial for comprehensive management of nuclear wastes. According to regulatory guidelines, specifically Notice No. 2021-16 issued by the Nuclear Safety and Security Commission, the determination of chelating agent content in radioactive waste materials is required to ensure proper management and safe disposal. However, only a few methods are available to analyze the chelators in various matrices such as concrete, metals, soil, and mixed solid wastes like plastics, vinyl, and rubber. Recently, we found a UV-Vis method based on an enzymatic reaction is inadequate for analyzing citric acid in radioactive waste with a complex matrix like concrete. To address this, we developed a method to determine the contents of EDTA and NTA using a UV-Vis spectrophotometer and citric acid using ion chromatography. The results showed good validity and reliability to determine the chelating agents in various radioactive wastes.

This study was carried out to recommend the recycling technology from the organic wastes generated in the neighborhood of a dam in Kroea. The order of production of the organic wastes without the suspended materials and energy corps are Chungju-dam(649.9 ton/day), Daechung-dam(525.1ton/day), Hapcheon-dam(485ton/day), Namgang-dam(478ton/day), and Soyang-dam(246.4ton/day). Because livestock excretions and nightsoil were composed of 72 to 93% of the total organic wastes, they should be proferly reflected in the plan of recycling. It was investigated that the biodegradability was 40~80%, biogas production, 0.22~1.70m3/kg VS, methan production, 0.15~1.07m3/kg VS, and methan contents, 63~79%, respectively, in case of the livestock excretions, which constituted over than 50% of organic wastes. Therefore, the appropriate technology for the recycling of organic wastes can be considered anaerobic co-digestion; this technology can create high added value because of using the fuel for new regeneration enery. SCFMR(Semi-Continuously Fed and Mixed Reactor) for an anaerobic digestion reactor was suited for the treatment of organic wastes because the retention time was relatively constant, compared to CSTR(Continuous Stirred Tank Reactor), power consumption was small, and operation and management of reactor was easy and economical.

이상의 결과를 종합하면, 평가대상 토양을 증류수로 20배 희석하여 200rpm 으로 30분간 진탕한 후 PDA (감자추출배지)와 혼합하여 121℃에서 20분간 살균한 후 Coriolus hirsutus (MKACC 50560) 균을 접종한다. 접종완료 후 25℃에서 5일간 배양한 후 균사 생장을 측정하여 담자균의 균사 생장률 (목적토양에서의 균사생장/PDA 에서의 균사생장×100)을 계산한다. 이 기준에 따라 균사생장률이 60%이상이 되면 대상 토양은 작물 생육에 적합한 토양이라고 추정할 수 있다. 이러한 방법은 토양의 건전성 평가를 위한 신속한 간이검사를 통하여 소량의 시료를 가지고 단기간 내 대량 분석을 가능하게 하여 토양 건정성 평가의 기초 자료로 사용될 수 있다고 사료된다.

Spent coffee grounds, activated sludge, chicken manure, and agricultural waste-derived biochar were used to manufacture eco-friendly and functional compost via the bioaugmentation of white rot fungus and plant growth that promotes beneficial microorganisms. Six lab-scale composting reactors were established to perform composting. After composting was completed over 45 days, the composts were analyzed for major elements, physico-chemical characteristics, compost maturity, and compost effectiveness on crop growth and quality. Concentrations of T-N and PO4 3− significantly increased in the composts that had been amended with biochar and/or white rot fungus compared to the control, while those of NO3 −-N, TOC and TOC/T-N had significantly decreased, indicating the occurrence of effective composting. Besides, the germination indices of these composts were also generally higher than the control by 10-34%, indicating that the composts were mature. The four composts amended with biochar and/or white rot fungus (TR-3, TR- 4, TR-5, TR-6) also appeared to stimulate more growth in lettuce compared to commercial organic fertilizers (by 36- 104%). Besides, composts TR-3 and TR-4 respectively enhanced DPPH scavenging activity in lettuce leaves by 58% and 49%, while TR-4 and TR-5 respectively enhanced the total phenolic content (TPC) by 44% and 37%. This implies that the amendment of biochar and the bioaugmentation of white rot fungus could facilitate the composting process for the production of quality functional compost that is able to enhance the antioxidant content in crops. Quality composts could better compete with the commercially available fertilizers in the market, leading to the eco-friendly recycling of organic wastes such as spent coffee grounds, sludge, chicken manure, and agricultural waste.

오늘날 인구밀도의 증가와 산업 활동의 증가로 하･폐수처리장이 급속하게 증가하였고, 이에 따라 하･폐수슬러지의 발생량이 많아지고 이를 감량 및 처리하기 위한 연구 및 개발도 증가하는 추세이다. 고함수(함수율 80%)의 특성을 가지고 있는 슬러지에 대한 처리 및 에너지화는 이전부터 많이 진행되고 있으나, 고형연료화에 있어서 높은 에너지 소비비용을 줄이기 위해 수열탄화의 공정에 대한 연구가 활발히 이루어지고 있다. 2012년부터 런던협약에 의해 유기성폐기물의 해양투기가 금지되면서 하수슬러지 뿐만 아니라 가축분뇨, 음식물류폐기물 등이 육상처리 및 에너지화의 방향으로 진행되어야 할 것이다. 이에 본 연구에서는 유기성폐기물 종류에 따른 수열탄화의 반응특성변화를 평가하고, 수열탄화 반응물의 탈수성, 고형연료 생산수율, 발열량, 탈리여액의 메탄포텐셜 등을 평가하여 종류별 최적의 수열탄화 반응온도를 평가해보았다. 또한, 유기성폐기물 종류별 수열탄화 적용에 따른 고형연료 생산성을 평가하여 유기성폐기물별 연료화 가치를 판단해 보았다.

This study has been conducted to optimum operating conditions for effective acid fermentation according to OLR(organic loading rate) in the mesophilic and thermophilic acid fermentation process. The results are summarized as follows. In order to obtain reasonable acid fermentation efficiency in performing acid fermentation of food wastes in thermophilic condition, organic loading rate was required below 20 gVS/L.d. As SCODCr/TKN, SCODCr/T-P of thermophilic acid fermented food wastes in organic loading rate 20 gVS/L.d were 18.9, 73.4 respectively, it was possible to utilize as external carbon source for denitrification in sewage treatment plant after solid-liquid separation as well as co-digestion of fermented food wastes and sewage sludge.

To utilize coastal aquaculture ground bottom sediment in which concentrations of harmful pollutants are low and organic content is high as an organic fertilizer alkaline stabilizers such as CaO, Oyster shell, Mg(OH)2 were added to the bottom sediment organic additives of livestock or food wastes. Nutritive qualities of crude fertilizers were measured to examine effects of alkaline stabilizers and organic waste additions. The Mg(OH)2-added crude fertilizer had significantly lower total carbon(T-C) and nitrogen(T-N) content, reflecting the dilution effect due to great amount of Mg(OH)2 addition. However, the addition of oyster shell had no significant effect on the T-C and T-N content of the fertilizer. P2O5 and K2O content was considerably higher in the mixed sample of aquaculture ground bottom sediments and livestock wastes than in the mixture of the sediments and food wastes, resulting from higher P2O5 and K2O content in livestock wastes. Addition of Mg(OH)2 increased the content of MgO in the crude fertilizer but significantly reduced the content of other nutritive elements such as P2O5, K2O and CaO. Addition of oyster shell as an alkaline stabilizer seemed to have the advantage of saving time and expenses for dryness due to its role as a modulator of water content. Moreover, additions of effect Mg(OH)2 decreased the concentrations of heavy metals in the fertilizer by the dilution while additions of oyster shell had no influence on heavy metal concentrations in the fertilizer.

The optimum dosage of quicklime in producing organic fertilizer using livestock wastes with a greater than 80% water content was analysed. After one day had elapsed to allow for the organic fertilizer to dry, the quicklime dosage and the composition of the organic fertilizer were analysed. Any from done to the organic fertilizer was also assessed. The amount of the quicklime required to stabilize livestock wastes was determined by water content of livestock wastes. For J farm(slurry style) of which livestock wastes have 94.6% of water concentration, less than 3% of total amount of livestock wastes, for H farm(scraper style) of which livestock wastes have 85% of water concentration, less then 4% of total livestock wastes and Y farm(traditional style) of which livestock wastes have 80% of water concentration, less then 5% of total livestock wastes. Generally, in order to pack the organic fertilizer, water containing quicklime-stabilized livestock wastes should be less than 35%. It takes 9 days to keep this water content for the wastes from H and Y farms(less than 85% in water content), and 12days for the wastes from J farm(94.6% in water content). According to the classification standard for compost constitution by Higgins, the crude fertilizers from all 3 farms had high grade K2O and CaO, the middle grade T-N and middle or low grade P2O5. Stabilization by quicklime is known to inhibit bacterial decomposition of organic matter and the activity of pathogenic organisms. In this study, more than 99.99% of coliform group, fecal group and viable cell count were reduced. Our results indicate that livestock wastes of greater 80% water content could be used to produce organic fertilizer without the addition of a material for moisture control.