• Asian-Australasian Journal of Animal Sciences
• /
• 제12권7호
• /
• pp.1049-1053
• /
• 1999

Chopped wheat straw (0.5-1.5 cm) was subjected to different treatment combinations in a $5{\times}4$ factorial arrangement involving the five levels of urea (0, 2, 3, 4 and 5%, w/w) and four levels of lime (0, 2, 4 and 6%, w/w) at 50% moisture and kept for 3 wk reaction period at about $35{^{\circ}C}$ in laboratory. Treated wheat straw samples were analyzed to study the associative effect of urea and lime on chemical composition, in sacco and in vitro digestibilities. Results showed that cell wall constituents (CWC) solubilized significantly (p<0.01) due to urea and lime treatment on one hand and substantially increase the crude protein (CP) on the other in wheat straw. The main effect on synergism of both chemicals was noticed on organic matter (OM), neutral detergent fibre (NDF), hemicellulose (HC), acid detergent lignin (ADL) and silica by solubilising their contents as a result of considerable increase in cell contents in treated wheat straw. The respective decreases were 5.45, 13.0, 37.23, 44.95 and 26.16% in different treatment combinations. The most interesting feature of the treatment was evident by increase in ash content on each level of lime application. CP content increase up to 12.78% due to urea treatment in comparison with untreated wheat straw (2.56%). The effect of solubilization of structural carbohydrates and increased crude protein due to synergistic effect of urea and lime were clearly seen on improved digestibility of OM and DM. The increase in ISOMD, ISDMD, and IVDMD were 21.67, 21.67, 16.24, and 17.5 units. The increase in digestibility were relative to additions of both chemicals and digestibility values increased with increasing levels of urea plus lime concentration in different treatment combination. The maximum improvement was noticed at 4% urea and 4% lime levels at 50% moisture for 3 wk reaction period in treated wheat straw.

• 한국환경농학회지
• /
• 제16권2호
• /
• pp.175-180
• /
• 1997

산성비에 의한 작물의 피해경감방안을 구명하고자 pot시험으로 사양토에 콩(단엽콩)을 공시작물로하여 석회물질을 토양(소석회), 엽면(석회유 1%, 석회유 2%), 토양 및 엽면(소석회+석회유 1%, 소석회+석회유 2%)에 처리하고, 인공산성비(pH 2.7)를 10mm씩 2일간격으로 50회 살포한 후 콩의 생육, 수량 및 수량구성요소, 가시적 엽피해율, 엽록소 함량, 광합성 능력, 식물체중 무기성분 함량, 시험후 토양의 이화학적 특성 등을 분석조사한 결과는 다음과 같다. 1. 인공산성비 45회 살포후 경장은 석회유 2%구에서, 엽수는 소석회+석회유 1%구에서 가장 컸으며, 엽폭, 경경, 개체당 분지수는 처리간에 유의성없이 비슷하였다. 인공산성비 살포에 의하여 전처리구에서 종실 수량이 감소하였으나, 석회물질의 처리구에서 종실 수량이 증가하였으나, 특히 소석회+석회유 1%구가 가장 좋았다. 2. 인공산성비 15 및 45회 살포후 엽피해율 경감효과는 석회물질의 시용이 효과적이었다. 3. 인공산성비 45회 살포후 엽록소 함량은 소석회+석회유 1%구에서 가장 높았으며, 인공산성비 30회 살포후 광합성 능력은 소석회구에서 가장 좋았다. 4. 인공산성비 살포로 식물체중 질소, 인산, 황 등의 함량이 증가되었으며, 소석회를 토양에 처리함으로써 식물체중 질소, 카리, 석회 등의 함량이 증가하는 경향이었다. 5. 인공산성비 살포로 토양의 pH는 낮아졌으나, 질소 및 황 함량은 증가되는 경향이었고, 인산, 석회, 카리, 고토등의 함량은 감소되는 경향이었다.

• Geomechanics and Engineering
• /
• 제15권4호
• /
• pp.957-964
• /
• 2018

In this study, a method of electrochemical consolidation is applied. This method utilizes electro-osmosis, which is an effective ground improvement technique for soft clays, and soil treatment using lime, which is the oldest traditional soil stabilizer. The mechanism of lime treatment for soil involves cation exchange, which leads to the flocculation and agglomeration. Five representative laboratory tests-an electro-osmotic test and four electrochemical tests with various proportions of lime-were performed on dredged marine clay. The objectives of this study are to investigate the effect of electrochemical treatment and to determine the optimum dose for optimal consolidation performance of dredged marine clay. The results show that a better consolidation effect was achieved in terms of current, temperature, and vane shear strength by using electrochemical treatment. The best results were observed for the electrochemical test using 4% lime content.

• 한국환경농학회지
• /
• 제29권1호
• /
• pp.47-53
• /
• 2010

본 연구에서 비소로 오염된 토양에 함유된 비소를 안정화시키기 위하여 4종류의 안정화제를 이용 처리하여 다음과 같은 결론을 얻었다. 안정화 처리에 사용된 오염토는 약알칼리성을 띄고 있으며, 입도분포 결과 사토계열이였고 57.5%의 비소가 무정형 및 비결정형 철/알루미늄 수산화물형태로 존재했다. 안정화 실험 결과 소석회/포틀랜드시멘트 혼합 안정화처리가 모든 안정화 처리와 비교 했을 때 현저한 우의를 보였으며 총 함량 30%로 토양오염 우려기준 20 mg/kg('나'지역)을 통과 하였다. 소석회/$FeCl_3{\cdot}6H_2O$ 혼합 이용시 효율적인 비소 저감효과룹 기대할 수 없었으며 소석회/NaOH는 효과적이었으나 소석회/포틀랜드시멘트 보다는 효율성이 제한적 이였다. 소석회/포틀랜드시멘트 혼합 안정화 처리 후 연속추출결과는 처리 전 오염토와 비교했을 때 특이적 흡착과 잔류대의 증가를 보였다. 특히 25wt%+10wt% 처리 시료에서 잔류태의 증가는 2배가 넘어 (16%에서 35.7%) 매우 안정적인 비소 존재 형태를 보여 비소 용출농도 저감에 현저하게 기여한 것으로 판단된다.

• Geomechanics and Engineering
• /
• 제8권5호
• /
• pp.687-706
• /
• 2015

Methods commonly used to evaluate the improvement of lime-treated expansive soil include swelling characteristics and unconfined compressive strength. In the field, lime-treated expansive soils are in compacted unsaturated state. Soil water characteristic curves (SWCCs) represent a key parameter to interpret and describe the behavior of unsaturated expansive soil. This paper investigates the use of SWCC as a technique to evaluate improvements acquired by expansive soil after lime treatment. Three different lime contents were considered 2%, 4% and 6% by dry weight of clay. Series of tests were performed to determine the SWCC for the different lime content under curing periods of 7 and 28 day. Correlations between key features of the soil water characteristic curves of lime treated expansive soils and basic engineering behavior such as swelling characteristics and unconfined compression strength were established. Test results revealed that initial slope ($S_1$), saturated water content ($w_{sat}$), and air entry value (AEV) play an important role in reflecting improvement in engineering behavior achieved by lime treatment.

• 환경위생공학
• /
• 제12권2호
• /
• pp.23-28
• /
• 1997

This study was conducted to know the possibility of reducing lime dosage by recycling sludge from bleaching wastewater lime coagulation settlement treatment at pulp mill process. In case of bleaching wastewater at the pulp mill process, when the lime dosage was increased, the removal efficiency of TSS(Total Suspended Solids) was increased, proportionally, but the organic removal efficiency was increased very slowly. It was concluded that sludge recycling at the lime coagulation settlement process was effective method to reduce the requirement of lime dosage. At the lime coagulation settlement process with sludge recycling, when the recycling number was increased, the organic removal efficiency was decreased, sharply. It was evaluated that the pH could be the basic standard for lime supplement by sludge recycling.

• 상하수도학회지
• /
• 제12권3호
• /
• pp.107-117
• /
• 1998

In order to removal turbidity at high turbidity, this study was carried to evaluate the coagulants(Alum, PACl, PACS) that was suited the characteristics of raw water in water treatment plants and to determinate the optimum method of lime feed. When the optimum coagulant was selected the organic matter removal was also investigated as $UV_{254}$. PACl, lime first feed had the highest turbidity removal efficiency rate as above 99.1% and then $UV_{254}$ removal rate was obtained over than 88.0%. If you had the necessary of the lime feed, among the method of lime feed time interval feed largely was improved than simultaneous feed. Also, lime feed dose had about 1/5 of coagulants dose in case of Alum and PACl, but always PACS should be considerated lime dose.

• Geomechanics and Engineering
• /
• 제17권2호
• /
• pp.195-206
• /
• 2019

The gypsiferous soils are significantly sensitive to moisture and the water has a severe destructive effect on them. Therefore, the effect of lime and silica fume addition on their mechanical properties, when subjected to water, is investigated. Gypsiferous soil specimens were mixed with 1, 2 and 3% lime and 1, 3, 5 and 7% silica fume, in terms of the dry weight of soil. The specimens were mixed at optimum moisture content and cured for 24 hours, 7 and 28 days. 86 specimens in the sizes of unconfined compression strength test mold were prepared to perform unconfined compressive strength and durability tests. The results proved that adding even 1% of each of these additives can lead to a 15 times increase in unconfined compressive strength, compared with untreated specimen, and this increases as the curing time is prolonged. Also, after soaking, the compressive strength of the specimens stabilized with 2 and 3% lime plus different percentages of silica fume was considerably higher than before soaking. The durability of the treated specimens increased significantly after soaking. Direct shear tests showed that lime treatment is more efficient than silica fume treatment. Moreover, it is concluded that the initial tangent modulus and the strain at failure increased as the normal stress of the test was increased. Also, the higher lime contents, up to certain limits, increase the shear strength. Therefore, simultaneous use of lime and silica fume is recommended to improve the geotechnical properties of gypsiferous soils.

• 한국토양비료학회지
• /
• 제3권1호
• /
• pp.29-34
• /
• 1970

산성(酸性) 류산염(硫酸鹽) 토양(土壤)에 석회시용(石灰施用)과 투수(透水) 무투수(無透水)가 수도생육(水稻生育)에 미치는 영향과 토양(土壤) 성분변화(成分變化)를 본바 다음 몇가지 결과(結果)를 얻었다. 1. 분얼 및 초장(草長)은 생육초(生育初)에는 별차이가 없으나 8월이후(月以後) 석회(石灰)의 효과가 나타남과 아울러 투수구(透水區)가 무투수구(無透水區)에 비(比)하여 효과적이었다. 2. 수수(穗數) 및 수당립수(穗當粒數), 임실률(稔實率)도 석회시용증가(石灰施用增加)에 따라 효과가 좋으며 무투수(無透水)에 비(比)하여 투수구(透水區)가 좋은 결과(結果)를 가져왔다. 3. 정조수량(精粗收量)은 표준구(標準區) 100에 비(比)하여 무투수(無透水) Ca 12me/100gr가 194% 투수구(透水區)의 Ca 4me/100gr가 268%, Ca 8me/100gr가 315% 증수(增收)되었다. 4. 석회시용(石灰施用)에 따라 호마엽고병(胡麻葉枯病) 병반(病斑)도 감소(減少)되었다. 5. 석회시용(石灰施用)에 따라 토양내(土壤內) 성분변화(成分變化)는 유효인산, 가용성(可溶性) $SiO_2$ 함량이 증가(增加)되었고 $Fe^{{+}{+}}$의 함량(含量)이 감소(減少)되었다.

• 상하수도학회지
• /
• 제19권2호
• /
• pp.125-134
• /
• 2005

Waste concrete powder was used to remove fluoride ions in highly concentrated fluoride wastewater. 92.6% of fluoride in 100 mg F/L wastewater was removed by 1% dose of the cement paste powder that represents characteristics of waste concrete powder, whereas the removal efficiencies of raw cement and lime were 47.3% and 96.4%, respectively. The cement paste powder was competitive to lime, common fluoride removal agent. Various Ca-bearing hydrates such as portlandite, calcium silicate hydrate, and ettringite in cement paste slurry can remove fluoride by precipitating $CaF_2$ and absorbing $F^-$ ions. In the experiments using both cement paste and lime, 50~67% of lime can be substituted by cement paste to satisfy fluoride effluent limitation of 15 mg/L. Since cement paste has higher acid neutralization capacity than lime, it can be recycled to neutralize more acid and to remove more fluoride. Therefore waste concrete powder can be more economical and viable alternative for lime in fluoride wastewater treatment.