• 한국물환경학회지
• /
• 제21권5호
• /
• pp.490-495
• /
• 2005

Since there are very limited numbers of thermophilic anaerobic digesters being operated, it is often difficult to start up a new one using sludge from an existing reactor as a seed. However, for obvious reasons it seems few attempts have been made to compare the start-up performance of thermophilic anaerobic digestion using different sources of seed sludges. The purpose of this study was to evaluate the start-up performance of anaerobic digestion using aerobic Waste Activated Sludge (WAS) from a plant and mesophilic Anaerobic Digested Sludge (ADS) as the seed source at both mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures. In this study, two experiments were conducted. First, thermophilic anaerobic reactors were seeded with WAS (VSS = 4,400 mg/L) and ADS (VSS = 14,500 mg/L) to investigate start-up performance with a feed of acetate as well as propionate. The results show that WAS started to produce $CH_4$ soon after acetate feeding without a lag time, while ADS had a lag time of 10 days. When the feed was changed to propionate, WAS removed propionate down to below the detection limit of 10 mg/L, while ADS removed little propionate and produced little $CH_4$. Second, in order to further compare the methanogenic activity of WAS and ADS, both mesophilic and thermophilic reactors were operated. WAS acclimated to anaerobic conditions shortly and after acclimating it produced more $CH_4$ than ADS. WAS at mesophilic temperature biodegraded acetate at the same rate as for thermophilic. However WAS at mesophilic temperature biodegraded propionate at a much faster rate than at thermophilic. WAS as the seed source of anaerobic digestion resulted in much better performance than ADS at both mesophilic and thermophilic temperatures for both acetate and propionate metabolism.

• 자원리싸이클링
• /
• 제17권4호
• /
• pp.66-76
• /
• 2008

반도체 산업에서는 다양한 형태의 반도체 소자를 제조하기 위하여 실리콘 웨이퍼가 사용되고 있다. 실리콘 웨이퍼는 실리콘 잉곳의 절단으로부터 만들어지며 이 공정에서 실리콘 슬러지가 발생한다. 반도체 소자의 사용처가 점점 증가함에 따라 실리콘 슬러지의 발생량 또한 증가하고 있는 실정이다. 최근 경제적 측면과 효율성 측면에서 폐실리콘 슬러지의 재활용 기술이 폭넓게 연구되고 있다. 본 연구에서는 폐실리콘 슬러지의 재활용에 관한 특허 기술을 분석하였다. 분석범위는 2007년 9월까지 미국, 유럽연합, 일본과 한국에서 출원 및 공개된 특허로 제한하였다. 특허들은 전체적으로 검색어를 사용하여 수집되었고, 기준 기술 이외의 것을 여과하였다. 특허기술의 경향은 년도와 국가별, 기업 및 관련기술 분야별로 분석되었다.

• 한국건설순환자원학회논문집
• /
• 제8권3호
• /
• pp.302-309
• /
• 2020

건설폐기물 중간처리시설에서 발생하고 있는 폐슬러지를 건조 분쇄한 순환 슬러지와 재활용되지 못하는 폐유리병을 가공처리한 순환 유리골재를 순환 상온아스팔트에 적용하기 위한 기초연구로서 순환 슬러지 및 순환 유리골재의 사용에 따른 순환 상온아스팔트의 특성을 비교·검토하였다. 그 결과 순환 슬러지를 채움재로서 사용량을 증가할수록 순환 상온아스팔트 혼합물의 마샬 안정도, 간접인강강도, 인장강도비는 감소하고 흐름값, 공극률은 증가하는 것으로 나타났다. 또한 순환 유리골재를 사용함으로서 순환 상온아스팔트 혼합물의 마샬 안정도, 간접인강강도, 인장강도비는 감소하고 흐름값, 공극률은 증가하는 것으로 나타났다.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
• /
• pp.165-172
• /
• 2004

Co-incineration of coal and wastewater sludge was r;erfonn:rl in a O.lMWth bench scale circulating fluidized bed combustor(CFBC) Sludge was received from a wastewater treatment plant in a dye industrial complex in Busan. Metropolis. Moisture content of received sludge was 80%. Coal and sludge mixture was prepared with weight ratio of 90/10, 85/15 and 80/20. Co-combustion characteristics of the coal and sludge mixture demonstrated stable combustion conditions. Component analysis, incineration characteristics, boiler performance was measured before and after the test and application for commercial 59MWth CFBC boiler. The release of hazardous components such as $SO_2$ and Cl was suppressed by the presence of inherent minerals of Ca, Na, K in coal and sludge mixture. Pre-drying was not essential but it was recommended for the benefits of manageability of sludge.

• The Korean Journal of Ceramics
• /
• 제2권3호
• /
• pp.125-130
• /
• 1996

Hematite iron ore and waste iron oxide sludge containing about 3-5 wt% $SiO_2$ were purified by three types of method developed on the basis of the Bayer process which is known as the purification process of bauxite ore. The basic principle of the developed methods lies in the fact that the impurities contained in the iron oxides, such as $SiO_2$ and $Al_2O_3$ are soluble in the alkaline reagents. Reaction of the raw materials with KOH was done in pressure vessel, at atmospheric pressure, and by both of these two. By the pressure vessel method $SiO_2$ content was reduced to below 0.5 wt% in the waste iron oxide sludge, while, in iron ore, $SiO_2$ remained at 2-3 wt%. The atmospheric pressure reaction rendered the waste iron oxide sludge $SiO_2$ content below 0.5wt% when the reaction temperature increased to above 90$0^{\circ}C$. The combined method of two previous methods was the most effective process and rendered the refined iron oxide about 300-400ppm of $SiO_2$. Using some refined iron oxides, Ba-ferrite was produced and magnetic properties were measured. The highest quality of magnetic properties obtained in this study were Br=2.09 G, bHc=1.99 KOe, iHc=4.54 KOe, $(BH)_{max}$=1.06 MGOe. Effect of sintering condition and chemical composition will be discussed.

• 한국축산시설환경학회지
• /
• 제1권1호
• /
• pp.77-82
• /
• 1995

In order to investigate the purification effects of livestock waste water, Modified Activated-Sludge Process(MASP) containing marine silica and volcanic ash-rock as the contact media and Sawdust-Soil Filter Method were used. The results obtained are as follows: 1. MASP which treated two metric tons' livestock waste water a day decreased BOD by 97.5% from 4,400.0mg/I to 108.8mg/I and SS by 98.0% from 5,335.0mg/I to 111.0mg/I. 2. MASP decreased BOD by 93.9% from 2,549.1mg/I to 156.6mg/I and SS by 96.3% from 3,521.9mg/I to 132.0mg/I when ten metric ton's livestock waste water was treated a day. 3. BOD and SS were decreased by 83.4% from 45.1mg/I to 7.5mg/I and by 83.4% from 47.5mg/I to 7.9mg/I when the supernatant layer treated by MASP was purified by Sawdust-Soil Filter Method.

• 한국버섯학회지
• /
• 제5권1호
• /
• pp.43-49
• /
• 2007

이상의 결과를 종합하면, 평가대상 토양을 증류수로 20배 희석하여 200rpm 으로 30분간 진탕한 후 PDA (감자추출배지)와 혼합하여 $121^{\circ}C$에서 20분간 살균한 후 Coriolus hirsutus (MKACC 50560) 균을 접종한다. 접종완료 후 $25^{\circ}C$에서 5일간 배양한 후 균사 생장을 측정하여 담자균의 균사 생장률 (목적토양에서의 균사생장/PDA 에서의 균사생장${\times}100$)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.

• 환경위생공학
• /
• 제13권1호
• /
• pp.16-25
• /
• 1998

Laboratory-scale experiment using anaerobic fluidized bed reactor was carried out to investigate the prehydrolysis step with caustic soda on the treatment efficiency of anaerobic sludge treatment, since the overall rate-limiting step for the complete anaerobic digestion of sludge was the hydrolysis step by extracellular bacterial enzymes of insoluble polymeric molecules. Reactors received a sludge which had not been pretreated, a 50-50 mixture of pretreated and untreated sludge, and the fully pretreated sludge. Hydraulic retention time of 10, 5, 2.5 days and 1 day were applied with an respective equivalent organic loading rate of 1.17, 2.23, 4.17, 11.24 gCOD/L/d. Reactor with the untreated sludge did not archieve adequate digestion even at the HRT of 5 days, and reactor, which received the 50-50 mixture, operated well at the HRT of 5 days, but began to show signs of unstable digestion at the HRT of 2.5 days. While, reactor, which was fed the hydrolyzed sludge, operated reasonably well at the 2.5 days, but was showing somewhat decrease in removal efficiencies. Results, therefore, have substantiated that the limiting reaction in the anaerobic treatment process is hydrolysis. The soluble COD did not significantly accumulate in the reactor as organic acid form, even when they were highly stressed. It was believed that this resistance to a build-up of organic acids and soluble COD behavior was mainly due to the maintenance of the methane bacteria in the fixed-film system which prevents washout as the organic loading increased. The anaerobic fluidized bed reactor was therefore effective for the digestion of waste activated sludge at short HRT.

• 상하수도학회지
• /
• 제24권1호
• /
• pp.85-92
• /
• 2010

본 연구에서는, 하폐수 처리시설에서 발생하는 기체상 무기악취물질을 저온 플라즈마 공정으로 제거하고, 악취물질과 반응 후 배출되는 오존 함유 배가스로 유기성 슬러지의 감량과 가용화 효과를 얻고자 복합반응기를 구성하였으며 일련의 실험을 진행하였다. 플라즈마를 통과한 대상 무기악취물질인 황화수소는 플라즈마를 단독으로 거쳤을 시 약 70%의 처리효율을 보였으며, 최종적으로 슬러지 반응조까지 통과했을 경우는 99% 이상의 처리효율을 보였다. 이 때 플라즈마 공정에서 배출되는 가스에 포함된 오존은 슬러지 반응조를 통과하여 90~100%의 제거효율을 보였다. 배가스가 슬러지 반응기에 산기되면, 유기물 산화가 단계적으로 진행되며 4시간 반응 시 슬러지의 TCOD는 약 50~60% 감소하고 SCOD는 4~5배 증가하였다. 따라서 가용화율은 운전 시간이 지날수록 증가하여 4시간 이후 약 10%까지 증가하였다. 결과적으로 저온 플라즈마와 슬러지 산기반응조 복합공정을 적용하면, 하폐수 처리시설 운영상에 나타나는 악취배출과 잉여슬러지 처분 문제에 동시 적용할 수 있을 것으로 판단된다.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.267-270
• /
• 2014

Since contaminants of syngas obtained from the biomass gasification are removed, the syngas is clean fuel. In this study a high-efficiency energy production system is developed. The system produces electricity using a waste pressure and feeds a low-pressure steam to Dyeing industrial complex. Also, iron oxide derived from dyeing sludge is utilized as a self-catalyst to reform a tar and reduce a tar emission from gasifier. This system increases the amount of syngas and finally achieves a highly efficient gasification.