• 유기물자원화
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• 제26권4호
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• pp.53-61
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• 2018

혐기성소화(AD)는 폐활성슬러지의 유기물함량을 바이오가스로 전환할 수 있는 가장 널리 이용되는 공정 중 하나이다. 그러나 현재 전통적인 혐기성소화에 의한 실제 메탄수율은 이론적인 최대 메탄수율에 미치지 못하기 때문에 메탄수율을 높일 수 있는 방안의 지속적인 연구가 필요하다. 따라서 본 연구에서는 폐활성슬러지로부터 메탄수율을 높이기 위해 생물전기화학 혐기성소화조를 이용하여 혐기성소화슬러지와 생슬러지의 혼합비율(3:7, 5:5)에 따른 메탄수율 및 유기물제거 효율에 미치는 영향에 관하였다. 그 결과 생물전기화학 혐기성소화 슬러지의 혼합비가 3:7과 비교하여 5:5일 때 가장 높은 메탄수율 294.2 mL $CH_4/L$(0.63배 증가)과 52.5%(7.5% 증가)로 유기물제거효율을 가지는 것으로 나타났으며 pH, 알칼리도와 VFAs의 농도도 안정적으로 유지되었다. 이러한 결과는 혐기성소화 슬러지의 혼합비의 증가는 생물전기화학 혐기성소화조의 안정적인 성능유지를 위해 효과적인 것으로 나타났다.

• 한국환경과학회지
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• 제10권5호
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• pp.365-371
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• 2001

The optimum dosage of quicklime in producing organic fertilizer using livestock wastes vith a greater than 80% water content was analysed. After one day had elapsed to allow for the organic fentilizer 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 quicklime0stabilized 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 12 days for the wastes from J (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 $K_2O$ and CaO, the middle grade T-N and middle or low grade $P_2O_5$. Stabilization by quicklime is known to inhibit bacterial decomposition of organic matter and the activity of pathogenic organisms. In this study, more then 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.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• 자원환경지질
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• 제27권5호
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• pp.469-477
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• 1994

Many researchers have investigated most representative sequential extraction method using various reagents for determining the chemical forms of metals in soils and sediments. In this paper, a newly modified method for sequential extraction scheme based on Tessier's method by Environmental Geochemistry Research, Centre for Environmental Technology, Imperial College, was introduced and examined. In comparison with Tessier's method, originally designed for sediment analysis by Atomic Absorption Spectrophotometry (AAS), the sequential extraction scheme has been developed for the multi-element analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The partitioning of particulate trace elements was classified into five fractions: (i) exchangeable, (ii) bound to carbonates or specially adsorbed, (iii) bound to Fe and Mn oxides, (iv) bound to organic matter and sulphides and (v) residuals. The experimental results of the pilot study for in-house reference material (HRM2) and certified international standard reference material (SRM2711) using the modified method showed not only reasonable precision and accuracy but also acceptable overall recovery rates. In addition, mine dump soils sampled in the Dalsung Cu-W mine, Korea were prepared and sequentially extracted using the method. Most of Cu was bound to organic matter/sulphides and residual fractions. The dominant fraction of soil Pb and Zn in the study area was found in the residuals. The fraction of Cd showed a wide variation between samples and could be found bound to the carbonates or specially adsorbed, oxides, organic fraction and residuals. The recovery rates of Cd, however, were poor due to relatively low Cd concentrations in soils. The heavy metals in these mine dumps appear to be in the more inert forms and should not be readily bioavailable. The soils, however, had very low pH values (average 4.1) and had sandy textures; consequently, rapid infiltration of rainfall may increase leaching of Zn and Cd which were found to be around 5 to 10% of the exchangeable fraction. As a result of the investigation of this study, it has been strongly recommended that these mine waste materials should still be considered a significant contaminant source and will need environmental remediation to prevent pollutants from being released into the environment.

• 한국물환경학회지
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• 제20권6호
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.362-372
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• 2010

다양한 하 폐수 처리공정 중 혐기성 소화공정은 이산화탄소 배출을 감소시키고 생성되는 메탄을 에너지로서 사용할 수 있는 장점을 가지고 있다. 본 논문에서는 이러한 혐기성 소화공정의 문제점과 보완점에 대해 살펴보았다. 가수분해과정은 혐기성 소화과정 중 율속단계에 해당하여 소화공정과정을 촉진시키고 바이오가스의 생산을 증가시키기 위하여 다양한 전처리 방법이 개발되어왔다. 현재 혐기성 소화공정을 위한 전처리 방법 중 열처리 방법, 초음파 처리, 기계적 처리방법, 화학적 처리방법 등이 상업적으로 이용되고 있으며, 이들 공정은 슬러지 플록 또는 세포의 파괴를 통해 세포분획물이 생물학적으로 분해될 수 있는 형태로 전환시키는 것을 목적으로 한다. 이러한 과정들 모두는 특정 상황에 따른 장점과 단점을 모두 지니고 있으므로 각 공정과정에 대한 이해와 이를 통한 적용을 통해 특정 슬러지에 적합한 최적의 전처리 공정을 도출해 낼 필요가 있다. 또한 혐기성 소화공정의 효율증대와 경제성 확대를 위한 혐기성 소화공정 개발이 필요하다고 할 수 있다.

• 한국환경과학회지
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• 제16권3호
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• pp.385-392
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• 2007

Currently, portable equipment for recycling of waste asphalt concrete (ASCON) has been used. However, any air pollution control devices are not attached in the simple portable one. Thus, a lot of air pollutants have been produced from recycling processes of waste ASCON which resulted from aging of paved roads or repavement of roads. This study deals with a preliminary result of concentration analysis of air pollutants obtained from a pilot and a real recycling processes of waste ASCON using simple portable recycling equipment. Air pollutants were taken from 4 steps of the pilot recycling process including an initial heating by liquid petroleum gas (LPG), intermediate heating and melting (H&M) process, final H&M process, and pavement processes using recycled ASCON at the recycling site. Also, air pollutants were taken front 4 steps of the real recycling processes including an initial H&M, final H&M and mixing, loading of recycled ASCON to dump trucks, and at the recycling site after leaving the loaded dump trucks for real pavement sites. The air pollutants measured in this study include volatile organic compounds (VOCs), aldehydes, particulate matter (PM: PM1, PM2.5, PM7, PM10, TSP (total suspended particulate)). The identified concentrations of VOCs increased with increasing time or degree for H&M of waste ASCON. In particular, very high concentrations of the VOCs at the status of complete melting, which is exposed to the air, of the waste ASCON just before paving tv the recycled ASCON at the recycling site. Also, considerable amount of VOCs were identified from the recycling equipment after the dump trucks leaded by recycled ASCON leaved the recycling site for the pavement sites. The relative level of formaldehyde exceeded 80% of the aldehydes Identified in the recycling processes. This is because the waste ASCON is exposed to direct flame of LPG during H&M processes. The PM concentrations measured in the winter recycling processes, such as the loading and rotation processes of waste ASCON into/in the recycling equipment for H&M, were much higher than those in the summer ones. In particular, the concentrations of coarse particles such as PM7 and PM10 during the winter recycling were very high as compared those during the summer one.

• 유기물자원화
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• 제8권4호
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• pp.100-110
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• 2000

음식찌꺼기의 사료화를 위한 발효처리시 수분조절제로 이용되는 재료 (톱밥, 버섯폐재, 밀기울, 야자박 등)와 발효방법 (호기성파 혐기성)및 발효기간이 음식찌꺼기 사료의 사료가치에 미치는 영향을 구명하기 위한 일련의 시험을 실시하였다. 본 연구의 시험설계는 농가 지도자료로 활용 될 수 있도록 하였다. 참나무 톱밥과 소나무 톱밥의 NDF(중성세제 불용성 섬유)함량은 각각 건물기준 93.5%와 95.4%로써 사료로 이용하기는 어려운 재료라고 할 수 있다. 톱밥을 수분조절제로 50% 혼합하여 $30^{\circ}C$에서 2일간 호기성발효를 했을때 NDF 함량은 발효 전 재료에 비하여 12% 증가했고 in vitro DDM (인공반추위 건물소화율)은 48% 감소했다. 참나무 톱밥은 소나무 톱밥에 비하여 양호하였으며, 버드나무 톱밥(80%)과 밀기울(20%)을 혼합하여 팽이버섯재배의 배지로 이용된 후의 폐재는 톱밥류에 비하여 사료가치가 우수한 것으로 나타났다. 발효된 사료의 NDF함량과 건물소화율은 이용된 수분조절제의 NDF함량에 주로 관계된다는 것을 알 수 있었다. 버섯폐재를 밀기울로 대체 했을때 밀기울의 대체율이 증가함에 따라 발효된 사료의 NDF함량은 직선적으로 감소했고 소화율은 직선적으로 증가했다. NDF함량이 높은 수분조절제를 이용한 호기성발효는 발효기간이 길어질수록 NDF함량은 증가되었고 건물소화율은 감소되었다. 그러나 밀기울 만을 이용하거나 밀기울이 함유된 수분조절제는 발효기간이 연장됨에 따라 조단백질 함량이 증가되었다. 혐기성발효는 호기성 발효에 비해 전 처리구에서 NDF함량은 감소되었고 건물소화율은 향상되었다. 버섯폐재와 밀기울을 수분조절제로 이용하여 실온에서 30일간 혐기적으로 발효한 사료를 유기산 조성과 pH가를 기준으로 발효상태를 판정할 때 우수한 것으로 나타났다.

• 유기물자원화
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• 제25권2호
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• pp.49-57
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• 2017

한국인이 가장 좋아하는 음식인 김치의 소비가 증가하면서 김치공장부산물(KWF)도 증가하였다. 본 연구는 KWF를 처리한 아주까리유박의 퇴비화에서 이화학적 특성의 변화와 시비에 따른 상추의 생육을 평가하였다. 처리구는 아주까리유박(60%)과 톱밥(40%)을 혼합한 대조구, KWF 35% 처리구(K-1), KWF 50% 처리구(K-2) 및 KWF 65% 처리구(K-3)로 설정하였다. KWF처리 후 pH, 유기물 및 미생물상은 처리구별 차이를 나타내지 않았으며, 대조구와 비교할 때, KWF처리구의 질소함량은 증가하였고, 유기물대 질소비는 감소하였다. 퇴비화 종료 후 KWF처리구는 비료공정규격에 적합하였으나 K-3의 염분은 1.91%로 다른 처리구들 보다 높았다. K-1처리구와 K-3처리구에서 상추의 생물중과 건물중은 대조구와 비슷하였다. 이러한 결과들은 김치공장 부산물이 퇴비원료로 사용이 가능하지만 작물에 안전한 아주까리유박퇴비의 생산을 위해서는 35% 이하로 사용하는 것이 적절함을 나타내었다.

• 유기물자원화
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• 제30권4호
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• pp.27-40
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• 2022

본 연구에서는, 탈수슬러지 및 음식물류폐기물의 효율적인 병합혐기성소화를 위해 폐기물의 혐기성소화 가능성 및 열화학적 전처리 방법에 대해 평가하였다. 폐기물의 혐기성소화 가능성 평가 결과, 음식물류폐기물이 탈수슬러지에 비해 혐기성미생물에 의해 분해 가능한 유기물 농도 및 methane yield가 각각 2.2배, 1.3배 더 높게 평가되었다. 바이오가스 발생량의 증대를 위해서는, 음식물류폐기물의 혼합비율을 증가시키는 것이 필요할 것으로 판단되었으며, 열화학적 전처리 효율은 반응온도, NaOH 주입량, 반응시간, 혼합비율 조건에 대해 평가하였다. 전처리 효율 및 탈수능을 통해 평가한 결과, 최적 열화학적 가용화 전처리 조건은 반응온도 140℃, NaOH 주입량 60 meq/L, 반응시간 60 min, 혼합비율 1:5로 평가되었다. 최적 열화학적 가용화 전처리 조건 적용 전과 후의 methane yield를 비교한 결과, 전처리를 적용한 경우에서, 가스발생속도 및 methane yield가 각각 1.6, 1.5배 증가하였다. 따라서, 탈수슬러지 및 음식물류폐기물의 효율적인 병합혐기성소화를 위해서는 음식물류폐기물의 혼합비율을 증가시키며, 폐기물의 전처리를 통해 가용화 효율을 증대시키는 것이 필요하다고 판단된다.