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.

폐기물 해양투기 방지를 위한 국제협약인 런던협약･의정서에 따라 2012년 가축분뇨의 해양배출이 전면금지 되었으며, 국내 가축분뇨 발생량은 2011년 128,621 ㎥/일에서 2014년 175,651 ㎥/일로 점차 증가하고 있는 실정이다. 또한 가축분뇨를 육상처리 시 발생하는 메탄가스로 인한 악취문제나 처리되지 못한 영양염류 및 고농도의 유기물이 하천으로 배출되어 부영양화를 일으키는 등의 문제가 대두되고 있다. Biochar는 혐기성 상태의 환경에서 분뇨와 같은 바이오매스를 열분해 시켜 생성한 고형물질이다. 최근 연구에 따르면 Biochar를 토양에 적용할 경우 주변의 이산화탄소를 장기간 저장하고 중금속을 흡착하며 토양 내 수분보유능력을 증가시키는 등 친환경 소재로써의 가치가 평가되고 있다. 따라서 본 연구에서는 수분함량이 높아 재활용이 어려운 가축분뇨를 열수가압탄화반응(Hydrothermal Cabonization, HTC)방법으로 Biochar를 제조하여, 중금속 흡착제로서의 사용가능성을 평가하고자 하였다. Biochar는 Stainless재질의 500 mL 용량의 반응기를 사용하였으며 온도, 반응시간, 입경에 따른 생성수율을 도출하고 각각의 원소분석, 삼성분 및 중금속 함량분석 등의 물리·화학적분석을 통한 특성분석을 수행하였다. 이 결과 원료와 비교하여 Biochar의 탄소성분은 약 25 % 증가했고 중금속 함량은 감소하는 경향을 보였다. 또한 흡착능력을 알아보기 위해 요오드 흡착성능을 분석한 결과, 원료 대비 약 52.4 %의 흡착성능 증가를 확인하였다.

산업혁명 이후 화석연료를 통한 에너지의 소비는 이산화탄소의 형태로 전례 없는 대기 중 탄소의 유입을 증가시켰다. 인류에 의해 발생된 이산화탄소 형태의 탄소 유입은 지구온난화와 같은 전 지구적 환경 문제를 유발하였다. 따라서 다양한 분야에서 탄소유입을 줄이기 위한 노력은 진행되어 왔다. 대표적으로 화석 연료의 대체가 가능한 바이오 연료는 비교적 쉬운 생산 공정과 기반시설에 대한 뛰어난 적응력으로 인해 상업화 되었다. 그러나 상업화 된 바이오 연료는 식용작물의 사용으로 인해 원료의 가격상승과 윤리 도덕적 문제를 초래하였다. 이를 극복하기 위해 폐유와 미세조류와 같은 비식용 작물의 바이오 연료 전환이 연구 되었다. 값싼 원료의 이점에도 불구하고, 원료의 불순물(유리 지방산, 수분 등)의 제거를 위한 전처리 공정의 추가와 다양한 공정 설비 및 운영비용은 새로운 바이오 연료의 생산기술 향상에 대한 요구로 나타났다. 특히, 전이에스테르화 반응을 통해 비교적으로 기술적인 연구가 활발히 진행된 바이오 디젤의 경우 초임계 조건, 효소, 초음파를 활용한 반응이 활발히 연구되어져왔다. 또한 다공성 물질을 활용한 촉매 모사 전이에스테르화 반응은 유리 지방산, 수분같은 불순물 하에서도 높은 전환율을 유지하는 것으로 확인 되었다. 촉매모사 전이에스테르화 반응은 수많은 공극이 존재하는 다공성 물질을 이용하여, 반응물의 충돌 빈도를 상승시킴으로써 촉매 사용으로 발생하는 단점을 최소화하였다. 이전까지 촉매모사반응의 다공성 물질로써 상업화된 실리카겔을 사용하였으나 바이오매스를 활용한 바이오 차의 다공성 물질로써 활용이 연구됨에 따라, 바이오매스 유래 바이오 차의 촉매모사 전이에스테르화 반응에 대한 적용 연구를 제시하고자 한다. 다양한 바이오차 중에 다양한 물리적 화학적 성질을 가지고 있는 계분은 촉망받는 다공성 물질로 여겨진다. 또한 폐식용유는 촉매모사 반응의 높은 유리 지방산 저항력을 증명하기 위해 원료로써 선택되었다.

The objective of this RDA-ARS cooperative study is to develop a biochar odor removal system to reduce swine odor from deep-pit swine farm. This study is divided into two phases: The first phase determines the swine odor removal potential of biochar made from various feedstocks and thermal processing conditions using a laboratory-scale biochar sorption column system. The second phase determines the effectiveness of a pilot-scale biochar swine odor removal system. It consists of designing and fabrication of a prototype, and installation of the prototype in a selected Korean swine farm. The effectiveness of the on-farm, pilot-scale biochar odor removal prototype will be determined by comparing influent and effluent odorant concentrations. Pine, oak, solid-separated swine manure, coconut shell, and poultry litter were selected as biomass feedstocks for producing biochar. Pellets of these biomass feedstocks were pyrolyzed at 350℃ and 500℃ using a Lindburg electric box furnace equipped with a gas tight retort. Some of these were also partially activated with steam at 700℃. In addition, Korean swine manure compost and imported coconut shell char were steam activated using a commercial rotary kiln system in Korea. All biochar samples were analyzed for their elemental compositions, volatile matter, fixed carbon, ash contents, size, density, and surface area. Selected odorous volatile organic compounds (VOCs) were pre-concentrated using preconditioned stainless steel sorbent tubes filled with Tenax TA® sorbent. The odorants captured by the sorbent tubes were then analyzed using a thermal desorption-gas chromatography-mass spectrometry system. For the laboratory sorption experiments, fresh manure samples from finishing swine farms with flushed (North Carolina) and deep-pit (Kentucky) manure management systems were collected from commercial swine farms in the U.S.

In the last 10 years, the annual number of published journal articles on biochar has increased dramatically. In addition, biochar research in South Korea has received much attention in a variety of research fields. The objectives of this study were to determine biochar research trends using bibliometric analysis methods and to suggest future research directions in South Korea. The data used in this study were compiled from online international and domestic scientific articles from 2010 to 2015. Annual production, institutes, main journal titles, research fields and frequency of keywords were analyzed to assess current research trends. As a result, biochar research in South Korea was found to be initially 10 years behind the global trend, but in 8th place globally in terms of published articles as of 2015. Future research on the long-term ecological/environmental effects of land-applied biochar and factory-scale production systems is necessary to promote practical use of biochar in South Korea.

유기성 폐기물인 하수슬러지는 특성상 다량의 수분과 유기물을 함유하고 있어 처리하기가 까다롭다. 우리나라에서는 하수슬러지를 대부분 매립과 해양투기에 의해 처리했으나 2005년 이후 직･매립이 금지되고 최근 해양투기마저 금지됨에 따라 슬러지 처리방법의 개발이 시급하다. 따라서 본 연구에서는 하수슬러지를 재활용하기 위해 열분해 반응 중 하나인 열수가압탄화 반응을 사용하여 Biochar를 생성하였고 생성된 Biochar의 미세기공을 발달시키기 위해 수산화칼륨(KOH)을 이용하여 화학적 활성화 반응을 통하여 활성 Biochar를 생성하였다. 또한 생성된 Biochar 및 활성 Biochar의 특성을 분석하고 카드뮴(Cd), 구리(Cu), 납(Pb), 아연(Zn), 니켈(Ni)에 대하여 중금속 흡착제로써의 흡착능력 실험을 통해 기존에 연구된 lab-scale실험과 비교평가 하였다. 기존연구에 따르면 하수슬러지를 200ml 용량의 반응기에서 열수가압탄화반응을 통해 하수슬러지 Biochar를 생성하고 수산화칼륨(KOH)을 이용하여 화학적 활성화 반응을 거친 후 카드뮴(Cd), 구리(Cu), 납(Pb), 아연(Zn), 니켈(Ni)에 대해 중금속 흡착능력을 평가한 결과 80% 이상의 효율이 나타났다. 본 연구에서는 하수처리장에서 발생되는 슬러지 중 탈수 후 배출되는 탈수cake를 이용하여 130L 용량의 반응기에 하수슬러지 100kg을 넣고 220℃ 온도에서 2시간 반응을 통해 Biochar를 생성하였다. 생성된 Biochar는 수산화칼륨(KOH)을 이용하여 600℃, 60분에서 화학적 활성화를 진행하였으며 이후 생성된 활성화 Biochar에 대해 삼성분, 원소분석, 중금속 용출, 양이온교환수지(CEC), SEM, FT-IR 실험을 진행하여 기본특성을 분석하였다. 그 후, 카드뮴(Cd), 구리(Cu), 납(Pb), 아연(Zn), 니켈(Ni)에 대하여 등온 흡착실험을 수행하여 중금속 흡착제로써 흡착성능을 비교평가 하였다.

Due to rapid industrialization and population growth uncontrolled release of heavy metals are entered into the waters. Among these heavy metals Pb(II) is one of the major toxic metal and in recent years the production and consumption of lead is increasing worldwide. Pb(II) can be entered to aqueous streams from several industries and can enter into the humans food chain through drinking water and crop irrigation. Lead can causes severe damage to the kidney, nervous system, reproductive system, liver and brain. The permissible level for lead in drinking water is 0.05 mg/l. Thus in recent years a number of methods and materials were developed to removal Pb(II) from aqueous solutions. Among these material bio-chars obtained from plant materials have gained special attention due to their low-cost and abundant nature. In present investigation we have developed magnetic bio-char composite from pine bark. Pine trees are wide spread throughout the South Korea and the bark from pine tree has no commercial use and is available as waste. Thus we have utilized this waste inexpensive material from preparing bio-char composite. The pin bark obtained was initially made into fine powder and washed several times with water and was filtered. To this powder an appropriate amounts of nitrate salts of cobalt and iron dissolved in ethanol solution was added and stirred for 15 minutes. This solution was oven dried at 70℃ and this was further calcined at 900℃ in nitrogen atmosphere. As obtained material was washed several times with water and dried in oven over night. This was used as adsorbent for treating lead contaminated aqueous solutions. As obtained bio-char composite was used to remove Pb(II) from aqueous solutions. Various parameters influencing Pb(II) removal like initial pH, contact time and initial concentration were studied. Effect of pH on Pb(II) removal was studied in the pH range from 2-8 at Pb(II) concentration 10 mg/L using an adsorbent dose of 300 mg. At below pH 3 a lower percent removal was observed whereas above pH 4>90% removal was observed. Further effect of contact time on Pb(II) removal was studied from time range between 10-180 min. Two kinetic models pseudo-first, pseudo-second-order models were used to evaluated the kinetic data and found that the data was better fitted to the pseudo-second-order model. From the overall results it was found that as prepared magnetic bio-char composite prepared from pin bark waste was effective and economic for treating Pb(II) contaminated aqueous solutions.

Land application of biochar (or charcoal) has increasingly been recognized due to its favorable effect as soil amendments. However, depending upon the nature of biomass and pyrolysis condition, biochar may be rich in hazardous inorganic elements. Giant Miscanthus showed its potential as a promising source for biochar manufacture but, the risk of heavy metal leaching from Giant Miscanthus-derived biochar (GMB) has not investigated. The objective of this study was to investigate the heavy metal leachability of GMB manufactured from 3 different temperatures (400, 500, and 700oC). Elemental composition of C, N, H, S, O and 18 metals were analyzed. Leaching concentration of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn was analyzed using 4 different methods (0.1 N HCl, 1 N NH4OAc, toxicity characteristic leaching procedure, and synthetic precipitation leaching procedure). For comparison, same analysis were performed for two char materials, municipal solid waste char (MWC) and sewage sludge char (SSC), manufactured from pilot-scale muncipal waste gasification plant. Elemental composition of GMB complied with the fertilizer guideline whereas the several heavy metal content (Cd, Ni, Pb, and Zn for MWC, Cr, Cu, Ni, and Zn for SSC) was beyond the criteria. From leaching test, concentration of heavy metals from GMB was positively increased with pyrolysis temperature and the acidity of extractant solution. Leaching concentration of plant nutrients (Ca, K, and Mg) was the highest by 1N NH4OAc. Meanwhile, leaching concentration of Cu from MWC and Pb from SSC exceeded the regulatory standard of Korea and US EPA, respectively. In conclusion, with respect to the risk of heavy metals, Giant Miscanthus-derived biochar will be suitable for land application as a soil amendment, while care should be taken for using municipal waste-derived char materials.