유기산을 이용한 콘크리트의 성능평가에 관한 연구

라덕관,정상철,이경동 한국공업화학회 2001 응용화학 Vol.5 No.2

This study was intended as an application for the preparation of flowing concrete using natural humic acid. Slump test, slumpflow test, L type test and V-lot test were carried out to check the workability characteristics of fresh concrete with two kinds of W/C ratio, 40% and 50%. The mechanical properties of hardened concrete were also investigated in terms of compressive strength and splitting tensile strength. At the results of this experimental study, the fluidity of fresh concrete was increased at the addition ratio of humic acid ranged from 0.6% to 1.8%, and decreased where the ratio exceed 2.4%. Flow test and L type test also showed the similar variation. The compressive strength variation was ranged 60∼70㎏f/㎠, and the splitting tensile one was ranged 10∼12㎏f/㎠, and the maximum strength was appeared at 1.2% addition ratio of humic acid.

TiO₂를 혼합한 모르타르의 강도 및 광촉매 활성 평가

라덕관,이경동,정상철,김영규,김성진 대한환경공학회 2003 대한환경공학회 학술발표논문집 Vol.2003 No.12

活性슬러지 混合液의 加壓浮上 分離

羅德寬 순천대학교 공업기술연구소 1990 工業技術硏究所論文集 Vol.4 No.-

An effective technique of sludge separation is required for concentrated sludge process. The Dissolved Air Flotation(DAF) has been shown to be efficient process for sludge separation. In order to study the optimal operation condition for sludge separation, the influence factors such as concentration of sludge, ratio of pressurized water flow, pressure, and quality of polymer are investigated by batch scale reactor of DAF. DAF is more effective than sedimentation for the separation of concentrated sludge. The critical ratio of pressurized water flow exist. Pressure affects the ratio of pressurized water flow. As the polymer dosage increases, floated sludge concentration becomes higher and effluent SS becomes lower.

게, 새우의 폐껍질로 부터 키토산 제조를 위한 새로운 공정에 관한 연구

안호근,라덕관 順天大學校 1996 論文集 Vol.15 No.1

The novel process for direct preparation of chitosan from spent shrimp and crab shells was studied with the aim of simultaneously performing the deproteinization and deacetylation in highly concentrated NaOH solution. The degree of deacetylation of chitosan by the process was increased with increasing reaction time, reaction temperature, and NaOH concentration, and the molecular weight was decreased due to the deep degradation during deacetylation. The relationship between the molecular weight and the degree of deacetylation for chitosan of shrimp and crab shells showed good linearity, then the molecular weight of chitosan may be estimated from the degree of deacetylation. The molecular weight of chitosan was 3∼5 time higher than that in the conventional process because of no degradation in the deprotenization, and the two chitosans was the same in the degree of deacetylation. These results led to the conclusion that the novel process was very effective method of direct preparation of high molecular weight chitosan from spent shrimp and crab shells.

가압부상법에 의한 도살장 폐수의 유지분 제거

라덕관,김유봉,허동균,김영규 순천대학교 기초과학연구소 1997 基礎科學硏究誌 Vol.8 No.-

The presence of grease and oil(G&O) in the influent wastes to wastewater treatment facility is one of the most serious problems affecting treatment efficiency. If the slaughterhouse wastewater is contained to G&O, pretreatment is required for G&O removal in wastewater treatment. The dissolved air flotation(DAF) has been shown to be efficient process for G&O removal in the pretreatment process. In order to study the optimal operation conditions for G&O removal, the control factors such as type and concentration of coagulant, ratio of pressurized water flow, and pressure are investigated by bench-scale reactor experiment of DAF. The G&O, COD and TOC removal efficiency of FeCl_3 were the higher than those of Al_2(SO_4)_3. The ratio of pressurized water flow was above 0.4 to take 90% or more removal efficiency of G&O. The best operation conditions obtained were 450㎎/l of FeCl_3 dosage, 0.43 of pressurized water flow and 4㎏/㎠ of pressure. The removal efficiency of G&O, COD, TOC and SS in these conditions were 90%, 76%, 80% and 76%.

埋立地 浸出水의 凝集處理

羅德寬,許東均 순천대학교 공업기술연구소 1997 工業技術硏究所論文集 Vol.11 No.-

This study was carried out to research on the colour and organic removal efficiency of landfill leachate by coagulation. In order to find out optimal conditions for the colour and organic removal efficiency. control factors such as sort and dosage of coagulant, concentration of leachate, and pH were investgated with experiments. 1) The colloid charge was measured by the colloid titration method. As for coagulatn used, Al_2(SO_4)_3 and C-486 had the least quantity of dosage at an isoelectric point. Cationic coagulants are very efficient because the constituents of colour in landfill leachate consist of colloids which are hydrophilic and negative charge. 2) The colour removal efficiency of Al_2(SO_4)_3 was the higher than that of FeCL_3. and, C-486 was the higher colour removal efficiency compared with A-110PWG. 3) Al_2(SO_4)_3 showed the best colour removal efficiency within the range of pH5 to 7. And, C-486 showed the best colour removal efficiency within the range of pH 7 to 9. 4)When the dosage of Al_2(SO_4)_3 was 600mg/ℓ, the COD removal efficiency was 44%. And, When the dosage of C- 486 was 100mg/ℓ, the COD removal efficiency was 47%. 5) The optimal condition achieved for colour and organic removal was as follows: the colour and organic removal efficiency of Al_2(SO_4)_3 was 86 % and 44% with a dosage of 600mg/ℓ at pH 6 and colour concentration of 400, and that of C-486 was 78% and 47% with a dosage of 100mg/ℓ at pH 8, respectively.

토양중에서 Pendimethalin의 흡착·탈착거동에 관한 연구

라덕관,박상숙,김유봉 대한환경공학회 1997 대한환경공학회 학술발표논문집 Vol.1997 No.12

活性슬러지 混合液의 流動層 凝集分離(Ⅱ) : Thickening and Dewatering 濃縮 및 脫水

羅德寬 순천대학교 공업기술연구소 1992 工業技術硏究所論文集 Vol.6 No.-

When the concentrated activated sludge was separated by the Fluidized Bed added cationic polymer, the characteristics of the thickening and the dewatering was investigated with plant experiment. The Fluidized Bed was operated under various conditions of polymer dosage, mixing intensity and superficial velocity. The dewatering was decreased with the increase of polymer dosage, but the water content was almost constant at experimental range. The mixing intensity did not affect the water content and the dewatering. In this experiment, the water content and the dewatering of sludge were respectively 92.2% and 78.8% at 20㎎/ℓ or polymer dosage, 40 rpm of mixing intensity and 15㎝/min of superficial velocity. The thickening and the dewatering of sludge can be effectively done by the Fluidized Bed.

活性슬러지 混合液의 流動層 凝集分離(Ⅰ) : Floc 密度의 特性 Characteristics of Floc Density

羅德寬,朱宰佑 순천대학교 공업기술연구소 1991 工業技術硏究所論文集 Vol.5 No.-

When the concentrated activated sludge was separated by the Fluidized Bed added cationic polymer, the characteristics of formated floc density was investigated with the plant experiment. Fluidized Bed was operated under varying conditions of polymer dosage, mixing intensity and superficial velocity. Floc density was increased with the increase of polymer dosage and the critical polymer dosage existed at 20-30㎎/ℓ. The mixing intensity provided during floculation did not affect floc density significantly, but if affects the formated floc sharp and the mixing pattern within Bed. The influential order of floc density was polymer dosage, mixing intensity and superficial velocity.

加壓浮上法과 流動層法을 이용한 活性슬러지 混合液의 固液分離에 관한 比較硏究

羅德寬,李基完 순천대학교 공업기술연구소 1995 工業技術硏究所論文集 Vol.9 No.-

When the concentrated activated sludge was separated by Dissolved Air Flotation(DAF) and Fluidized Bed(FB), the influence factors such as concentration of raw sludge, floating and settling velocity, effluent SS, concentration of floated and settled sludge, and polymer dosage were investigated with experiment. The solid liquid separation of concentrated activated sludge could be barely expected by sedimentation, but it could be easily done by DAF and FB. The sludge in FB was about 6.0%. Settling velocity in FB was about two to three times faster than floating velocity in DAF within the polymer dosage of 5 to 20㎎/l. FB was more effective than DAF for the separation efficiency of sludge. The optimal polymer dosage of DAF and FB were 5 ㎎/ℓl and 20㎎/ℓ, respectively.