The pickling brine generated from the salting process of kimchi production is difficult to treat biologically due to very high content of salt. When pickling brine is treated and discharged, it cannot satisfy the criteria for effluent water quality in clean areas, while resources such as the salt to be recycled and the industrial water are wasted. However, sterilization by ozone, UV and photocatalyst is expensive installation costs and operating costs when considering the small kimchi manufacturers. Therefore there is a need to develop economical process. The study was conducted on the sterilization efficiency of the pickling brine using electrochemical processing. The electrochemical treatment of organic matters has advantages over conventional methods such as active carbon absorption process, chemical oxidation, and biological treatment because the response speed is faster and it does not require expensive, harmful oxidizing agents. This study were performed to examine the possibility of electrochemical treatment for the efficient processing of pickling brine and evaluated the performance of residual chlorine for the microbial sterilization.

수열탄화 (HTC, Hydrothermal Carbonization)는 수분함량이 높은 바이오매스를 바로 적용하여 닫힌계에서(closed system)에서 승온 시키면 150℃∼250℃범위에서 열수(hot water)에 의하여 고형물의 유기물 일부가 분해되기 시작하여, 탈카르복실화(decarboxylation)와 탈수(dehydration)반응이 유도되며 O/C, H/C 비율을 낮추고 탄소고정을 통해 바이오매스 고형연료의 에너지밀도를 높여 연료로서의 특성이 향상된다. 또한 수열탄화 반응시 높은 수분함량을 건조하여 수분을 증발시키지 않고 물로 분리함으로서 수분 제거시 소비되는 에너지를 일반 건조기술 대비 50%이상 절감함으로서 하수슬러지 고형연료화의 경제성을 향상 시킬 수 있다. 이렇게 분리된 액체생성물에는 유기물 분해에 의해서 용해성 유기물이 다량 농축되어 혐기소화의 전처리 기술로도 적용되고 있다. 본 연구에서는 I시 하수슬러지를 1년간 매달 sampling하여 계절별 하수슬러지 물리화학적 특성 변화와 수열탄화 적용 시 반응 및 연료 특성 변화를 확인하였다. 따라서 상용화 수열탄화 기술을 적용시 계절에 상관없이 안정적인 고형연료 확보 가능성을 확인하였다.

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.

Recently, production of sewage and wastewater sludge have increased sharply with the population density and related industrial activity. As a result, studies of sludge treatment and reduction have been conducted and a pre-treatment method that uses thermal hydrolysis has emerged as a solution to this problem. To address problems with the thermal hydrolysis pre-treatment process, the deaeration and nitrogen recovery processes have been set up together, thus generating factors that inhibit dewaterability. In this study, the effect of pre-treatment, deaerated sludge on dewaterability-inhibiting factors (pH, temperature, aeration rate) was evaluated and alternative solutions were prepared. First, the dewaterability improvement effect increased rapidly at 190°C or higher when thermal hydrolysis pre-treatment was applied. Then, 1 L of thermal hydrolysis pre-treatment reactants at 190°C were injected into 1, 5, and 10 L/min air flows at 50°C, but no significant difference in capillary suction time (CST) or time to filter (TTF) was found. The dewaterability improved when the temperatures of the pre-treatment reactants varied between 30, 50, and 70°C under aeration at 5 L/min. However, when the pH was increased to 7, 9, or 11 at 5 L/min and 50°C, the dewaterability worsened by at least 10 times relative to the hydrolysis pre-treatment reactants. The zeta potential decreased from -30 mV to -50 mV as the pH increased. Thus, the stabilities and dispersities of the reactants increased due to the repulsive force of the particles. This was confirmed to be the cause of poor dewaterability. A coagulant can be used to solve to this problem, or the deaeration process can be placed after solid-liquid separation and the heat of thermal hydrolysis can be extracted via heat exchanger.

수열탄화(HTC, HydroThermal Carbonization)는 수분함량이 높은 바이오매스를 바로 적용하여 닫힌계에서 (closed system)에서 승온시키면 150℃~250℃범위에서 열수(hot water)에 의하여 고형물의 유기물 일부가 분해되기 시작하여, 탈카르복실화(decarboxylation)와 탈수(dehydration)반응이 유도되며 O/C, H/C 비율을 낮추고 탄소고정을 통해 바이오매스 고형연료의 에너지밀도를 높여 연료로서의 특성이 향상된다. 또한 수열탄화 반응시 높은 수분함량을 건조하여 수분을 증발시키지 않고 물로 분리함으로서 수분 제거시 소비되는 에너지를 일반건조기술 대비 50%이상 절감함으로서 하수슬러지 고형연료화의 경제성을 향상 시킬 수 있다. 이렇게 분리된 액체생성물에는 유기물 분해에 의해서 용해성 유기물이 다량 농축되어 혐기소화의 전처리 기술로도 적용되고 있다. 본 연구에서는 Lab scale과 1ton/day pilot plant를 이용하여 수열탄화를 하수슬러지에 적용하여 반응특성 및 연료 효율 향상을 확인하였다. 반응온도별 각 반응생성물의 특성 파악을 통해서 최적의 반응조건을 도출하였다. 또한 수열탄화 반응물에서 후단의 혐기소화 공정의 저해인자 제거를 위한 질소회수 공정으로 생기는 pH 변화에 따른 탈수특성 변화와 원인을 확인하였다.

지속적인 경제 성장으로 인한 생활 패턴 및 소비구조의 변화에 의해 폐기물 발생량은 급격히 증가하였으며, 발생 및 특성에 따른 적정처리에 대한 어려움을 겪고 있다. 특히, 유기성 폐기물은 2012년 해양 투기의 전면금지에 따라서 대체할 수 있는 처리 방안에 대해 지속적으로 방법을 강구하고 있는 실정이다. 음식물 폐기물의 경우 높은 유기물 함량과 높은 수분함량으로 직접적인 연료화보다는 퇴비화 및 사료화 등으로 처리하고 있으나, 악취 및 폐수 처리문제 등이 야기되고 있다. 본 연구에서는 수열탄화를 이용하여 Biochar를 생산하고, 생산한 Biochar 특성변화에 대한 연구를 진행하였다. 수열탄화의 온도변화에 따라서 음식물퓨 폐기물의 유기물의 특성 변화 및 연료 특성 변화에 대한 상관관계와 적용성에 대한 평가하였으며, 실험조건은 180-240℃에서 1시간동안 반응하였다. Biochar의 특성분석을 위행원소분석, 공업분석, 발열량 및 유기물 변화 등을 분석하였다. 수열탄화를 통해 발열량이 증가하였으며, 탈수성이 향상되는 결과를 얻었다. 음식물의 유기물의 용해에 의해 Product yield는 낮아지는 결과를 보였다. 화학적으로는 탄소함량의 증가를 통해 발열량이 증가하였다고 판단되며, 높은 온도에서는 분해율이 높아서 고형물 및 탄소 함량이 낮아지는 결과를 알수있었다. 수열탄화를 통해 얻어진 Biochar는 국내 Bio-SRF 기준에 적합한 결과를 보였으며, 수열처리는 음식물류 폐기물 처리의 한 방법으로 제시가능하다고 판단된다.

In this study, hydrothermal carbonization is used to recover energy from sludge. This hydrothermal carbonization is a feasible sustainable energy conversion technology to produce biofuel for renewable energy. The experiments were conducted at 170oC up to 220oC for a 30-min holding period to determine the optimum conditions for hydrothermal carbonization in a lab-scale reactor to apply to a scale-up reactor (1 ton/day). The biochars from sludge were assessed in terms of dewaterability characteristics and fuel properties. The results showed that the optimum temperature of labscale hydrothermal carbonization was 190oC. The 1 ton/day hydrothermal carbonization pilot plant operated at 190oC. The biochar had higher energy content but the char yield sharply decreased. Therefore, an energy of about 49% could effectively be converted from sludge biomass. This sludge from municipal wastewater treatment is a potential energy resource because sludge is composed of organic substances.

Recently, it is increase in the processing of organic waste using anaerobic digestion. Therefore, the studies on theprocessing method for increasing the anaerobic digestion waste water. Among them, purification treatment and liquidfertilizer have been issues. But, efficiency of the ways is very insufficient. While increasing the anaerobic digestionprocess, increasing study for the treatment of anaerobic digestion waste water. In this study, It was evaluate thecharacteristic of liquid fertilizer of anaerobic digestion waste water as affected by aeration rate and solid-liquid separation.Also, we review liquid fertilizer degree using maturity assessment indicators of liquid fertilizer by national institute ofanimal science. As a result, insertion of air(3.5L/min) sample after solid-liquid separation appeared was the highest. pHand color was difficult to understanding correlation with liquid fertilizer among maturity assessment indicators(seedgermination, ammonia(NH3), hydrogen sulfide(H2S), electrical conductivity(EC), pH, color, etc).

런던협약에 의해 해양투기로 대부분이 처리되던 폐기물은 금지되면서 감량화 및 자원화를 고려하게 되었다. 국내의 가축 도축량은 계속해서 늘어나고 있다. 그래서 발생되는 도축 폐기물의 양 또한 늘어나게 되었다. 돼지, 닭, 소 등 가축의 가공 후 발생된 폐기물은 유기성폐기물로 하수슬러지 및 음식물쓰레기처럼 수분을 많이 함유 하고 있어 감량화 및 자원화에 어려움이 많다. 따라서 본 연구에서는 반응온도별로 수열탄화의 특성을 평가하였고, 고형물의 상호관계를 파악하여 감량화 및 에너지화에 대한 효율성을 평가하였다. 그 결과 반응온도가 증가할수록 탈수성 증가 및 고형물의 물리적형태 변화에 따라 감량화율이 높아졌고, 높은 에너지화율을 나타내었다.

The organic solvent is used in many industries. Generation of waste organic solvent is continuously increasing. The 2009 years total domestic production organic solvent is in use 21% total designation waste production with 682 thousand tons. processes of a waste organic solvent and management issue is increasing in advanced countries. To resolve this problem, evaluate the characteristics of a batch distillation column purification to propose alternative. Therefore, this study compares a refinement recovery characteristic of simple distillation and 10-stage distillation tower. It grasps a characteristic regarding refinement recovery of the waste organic solvent (Propylene Glycol Mnomethyl Ether Acetate)PGMEA which occurred at LCD processes through study of a hundred steps of distillation tower. In this study, the evaluate scale-up separation characteristics difference using 10-stage and 100-stage batch distillation column. The actual process of making a demonstration plant appointed by using waste organic solvents of high purity propose a method for recycling.

Diverse studies are being conducted on sewage sludge treatment and recycling methods, but the demand for a lowcost treatment technology is high because the sewage sludge has an 80% or higher water content and a high energy consumption cost. We want to apply the thermal hydrolysis reaction that consumes a small amount of energy. The purpose of this study is to quantify the thermal conductivity of sewage sludge according to reaction temperature for optimal design of thermal hydrolysis reactor. We quantified continuously the thermal conductivity of dewatered sludge according to the reaction temperature. As the reation temperature increased, the dewatered sludge is thermally solubilized under a high temperature and pressure by the thermal hydrolysis reaction. Therefore, the bond water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry of a liquid phase. As a result, the thermal conductivity of the sludge was more than 2.6 times lower than that of the water at 293 K, but at 470 K and above, became 0.708 W/m·K, which is about 4% lower than that of the water.

Slaughter of cattle, pigs, and chickens is continuously increasing. Slaughter of chickens has especially increased by approximately 50% from 2003. The quantity of poultry slaughter waste is currently approximately 120,000 tons/year, and undergoes consigned treatment. Via this process, the waste must be used as a resource and an energy source. For this purpose, the waste volume can be reduced and solid fuel can be obtained from the THR (Thermal Hydrolysis Reaction) that consumes a small amount of energy. In this study, The test was conducted at a reaction temperature of 170-220oC and for 1h at the final temperature. According to the CST (Capillary Suction Time) and TTF (Time to Filter) evaluation, the dehydrating efficiency was good after the temperature reached 190oC, and did not significantly differ at the 190oC and higher reaction temperatures. The heating value of the dehydrated solid product was 7,000-7,700 kcal/kg, and its yield rate decreased from approximately 80% to 60% with the increase in the reaction temperature. The results of the BMP test also showed that the anaerobic digestion efficiency decreased at the reaction temperatures of 200oC and higher. From the overall evaluation of the dehydrating efficiency, solid fuel quality, and anaerobic digestion efficiency during the thermal hydrolysis of poultry slaughter waste, it is concluded that the optimal operating temperature is 190oC.

Diverse studies are being conducted on sewage sludge treatment and recycling methods, but the demand for a lowcost treatment technology is high because the sewage sludge has an 80% or higher water content and a high energy consumption cost. For this purpose, the waste volume can be reduced and solid fuel can be obtained from the Thermal Hydrolysis Reaction (THR) that consumes a small amount of energy. The experiment was conducted at a reaction temperature of 170-220oC and maintain for 1 hour at the final temperature. According to the Capillary Suction Time (CST) and Time to Filter (TTF) evaluation, the dewater ability was good after the temperature reached 200oC and did not significantly differ at the 200oC and higher reaction temperatures. The heating value of the dehydrated solid product was 3,800-4,200 kcal/kg, and its yield rate decreased from approximately 80% to 60% with the increase in the reaction temperature. To evaluate the efficiency of anaerobic digestion, the water quality of the liquid product was analyzed based on the reaction temperature. At the temperatures of 200oC and higher, the concentration of ammonia, which increases the pH and hinders anaerobic digestion rapidly increased. From the overall evaluation of the dehydrating efficiency, solid fuel quality, and anaerobic digestion efficiency during the thermal hydrolysis of sewage sludge, it is concluded that the optimal operating temperature is 200oC.