김응호Eung Ho Kim

DOI: Vol.17(No.5) 549-555, 2001

N/A

박재로Jae Roh Park,임현만Hyun Man Lim,우효섭Hyo Seop Woo

DOI: Vol.17(No.5) 557-564, 2001

This study applies to the Upflow contact oxidation Process for river purification. The ability of the plant to treat polluted stream water was determined and a suitable operating conditions were deduced. This study also presents a plan for effective use and operation maintenance. The results from the treatment efficiency from the Upflow contact oxidation method showed that the removal of BOD and SS depends more on the existence of aeration rather than treatment time. The best removal was seen at 2 hours retention time, and the presence of aeration proved to be twice as effective compared to the absence of aeration. The application of the Demo Plant in the field indicated a decrease in the inflow and outflow concentrations of BOD from 8.2㎎/ℓ to 4.3㎎/ℓ. The average removal percentage was 38%. However, at the 1.9 hour point of the 2 hour retention time, a maximum removal rate of 50.7% was seen. Also, if the operation were continued for 200 days, the pore is reduced 3.14% and backwash will be needed two times per year.

장윤영Yoon Young Chang,배범한Bum Han Bae,지원현Won Hyun Ji,장윤석Yoon Seok Chang,강정우Jung Woo Kang

DOI: Vol.17(No.5) 565-571, 2001

This study attempts to elucidate the possibility of treating dyeing wastewater by steelers` dust/H₂O₂ system in a well-mixed batch reactor. Experiments were conducted to investigate the effects of operating variables such as pH, dust and H₂O₂ dosages and H₂O₂ injection method on the treatment efficiency. Contaminant concentrations were identified by TOC(Total Organic Carbon) analyzer. Experimental observations showed the possibility of steelers` dust as a catalytic reagent in the H₂O₂/dust system. The batch experiments showed that the optimal H₂O₂ and dust dosage, 20g/L dust + 1,500㎎/L H₂O₂ removed about 85% of initial TOC concentration(100㎎/L) within 30 min. And the TOC removal in the H₂O₂/dust system effectively proceeded only within a limited pH range of 3-4. The steelers` dust-catalyzed oxidative treatment of dyeing wastewater was more efficient compared with the FeSO₄-catalyzed system(Fenton oxidation) for the removal rate and the cost.

양원영Won Young Yang

DOI: Vol.17(No.5) 573-579, 2001

In this study, the modeling and pilot test were conducted to compare the performance of the inclination plate settler with the normal settler. This study used STAR-CD modeling made in Adapco company. From the modeling test, sedimentation efficiency of normal and inclination plate settler were found to be 57.4% and 66.1%, respectively. Those obtained from pilot test were 59.5% and 67.8%, respectively. The increments of the efficiency in the modeling and pilot were 8.7% and 8.3%, respectively. As a result, more than 8% of sedimentation efficiency was increased with applying the inclination plate settler.

전석준Seok Jun Jeon,최명수Myung Soo Choi,현경학Kyoung Hak Hyun,윤여진Yeo Jin Yoon

DOI: Vol.17(No.5) 581-595, 2001

A Hybrid process which consists of a bench-scale Upflow Anaerobic Fixed Bed Reactor(UAFBR) packed with iron media and Anoxic/Oxic(A/O) tank was tested to investigate the removal efficiencies of organic substances, nitrogen and phosphorus from domestic wastewater. Two types of systems were operated in parallel with different return sludge ratios and SRTs. One was the hybrid process and the other was the A/O process. In comparing the hybrid process with the A/O process with respect to phosphorus removal efficiency, the performance of the hybrid process was much better than that of the A/O process alone, because phosphate ions in wastewater were combined with iron cations from UAFBR. Nitrogen removal efficiency of the hybrid process was less than that of the A/O process alone. These results were originated from differences of influent COD concentrations, that is to say, influent COD/N ratio of the A/O process was greater than that of the hybrid process.

김응호Eung Ho Kim,김성호Seong Ho Kim,조진규Jin Kyu Cho

DOI: Vol.17(No.5) 597-604, 2001

A possibility of digested sludge cake solidification using blast furnace slag as a solidifying agent is investigated where the quick lime is used as a solidifying aid. Several tests are performed to investigate the solidifying effects and the applicability of the solidified sludge cake to daily or intermediate landfill cover material. The unconfined uniaxial compressive strength, pH, leaching of heavy metals, submerged effect and curing effect are measured, and XRD, SEM and EDS analysis are also conducted. The mixing ratios of solidifying specimen mixed with the blast furnace slag and the quick lime are varied in the range between 30 and 50, 5 and 20 percent of the digested sludge cake by weight. The best compressive strength results when the mixing ratio is 40 : 20. Data values for leaching pH and the concentration of leaching heavy metals from specimen for items of Cu, Pb, Cd, and Cr^(6+) are much less than those given in the Korean toxic waste criteria. The differences between air tight(moist) and air dried curing method are significant, but 1-day submerged curing shows little effects on the weight and the strength of specimen. Also, the compressive strength of specimen by air dried curing is much greater than by air tight curing. XRD analysis shows that the main solidification products are CSH, CAH and Ca(OH)₂. The microstructure analysis by SEM shows that needlelike crystals appear as the solidification proceeds. Also, the EDS analysis on these crystals confirms that the main components are Ca, Si and AI.

박석균Suk Gyun Park,강선홍Seon Hong Kang,정태학Tai Hak Chung

DOI: Vol.17(No.5) 605-611, 2001

The characteristics of swine wastewater are different according to the type of pigsties, method of removing swine wastewater, quantity of washings, etc. It is difficult to get granular which is required for UASB because swine wastewater consists of high concentrations of solid and NH₃. A purpose of this study is to test the applicability and solve the problems happened in operating UASB in the field. Non-granular microorganisms acclimated to the substrate of swine wastewater, granular microorganisms produced in the brewing wastewater and their mixture were seeded respectively. When diluted wastewater($lt; TS 2%) was injected into the reactors, the reactor which was seeded with the mixture showed the highest COD removal rate. When raw wastewater of slurry type was injected into the reactors, all reactors showed the rise of sludge layer regardless of HRT and type of seedings.

전민하Min Ha Jeon,최상일Sang Il Choi

DOI: Vol.17(No.5) 613-617, 2001

This study examined the applicability of the flushing effluent treatment using immobilized cells. Endosulfan concentration and pH of flushing effluent were 5㎎/L and 5.6, respectively. The removal efficiencies for the HRT of 1, 3, and 5 hours were 62, 82, and 89%, repectively. After about 80 hour operations, the steady state conditions were reached. When endosulfan concentrations of flushing effluent were increased to 50 and 100㎎/L under 3 hour HRT operation condition, the removal efficiencies were decreased to about 70 and 50%, respectively. When pHs were changed to 4.0 and 9.0, the removal efficiencies were 73% and 66%, respectively. When the flushing effluent was re-circulated, removal efficiency was enhanced upto 90%. When the flushing effluent injected was aerated, 93% of removal efficiency was achieved without any re-circulation of the flushing effluent, and it might be resulted from the enhancement of the microbial activities.

오종민Jong Min Oh,노성혁Sung Hyeuk Roh

DOI: Vol.17(No.5) 619-625, 2001

In this study, a hydrocyclone operated by centrifugal force was examined as a part of dredge system of lake sediments. It helps dehydration of the sediments and enables the classification of fine particles in the stable and sanitary treatment. Several experiments were performed focusing on the separation efficiency under the condition of room temperature with virtual sediment samples and simulated particles. As a result of the experiment, it was found that the apex size and inlet pressure greatly affected the cut diameter(d_(50)) and reduced efficiency.

이현동Hyun Dong Lee,배철호Chul Ho Bae,박정훈Jeong Hoon Park,정원식Won Sik Chung,곽필재Phil Jae Kwak

DOI: Vol.17(No.5) 627-635, 2001

The effects of water quality characteristics on internal corrosion of galvanized steel service pipe(GSP) in the building were evaluated qualitatively and quantitatively, and the time of its replacement were predicted in the study. The results showed that water quality characteristics of Nakdong River water resources in both anti-corrosion factors(pH, Alkalinity, Hardness etc..,) and corrosion factors(Conductivity, Chloride ion, Sulfate ion etc..,) were higher than any other water quality of major water resources. And water corrosivity of water resources were seem to depend on the method of evaluation such as LI, LR, and BI. And Nakdong River water resources also was thought to be high in the evaluation of corrosion indices such as LR and BI especially. Therefore the results of the evaluation also showed that water corrosivity of Nakdong River water resources were higher than any other water resources entirely. Corrosion rate measurement by Corrator showed that uniform and pitting corrosion rates were 0.075 mmpy and 1.333 mmpy in Nakdong River water resources, 0.070 mmpy and 0.834 mmpy in lake water resources, and 0.065 mmpy and 0.445 mmpy in Han River water resources. And pitting corrosion were thought to be predominant corrosion type in GSP. The time of GSP replacement were thought to be about from 14.1 years to 16.2 years if considering only a straight part of GSP by uniform corrosion rate. Otherwise if a screw part, the time of Its replacement would be about from 6.7 years to 7.7 years. But if pitting corrosion rate, the time would be shorter. Residual thickness measurement of GSP by ultrasonic waves showed that average and maximum corrosion rates were 0.054 mmpy and 0.084 mmpy in Nakdong River water resources, 0.041 mmpy and 0.055 mmpy in lake water resources, and 0.022 mmpy and 0.032 mmpy in Han River water resources, and all average and maximum corrosion rake were lower than corrosion rate by Corrator.

이용두Yong Doo Lee,이기호Ki Ho Lee,김현희Hyun Hee Kim

DOI: Vol.17(No.5) 637-642, 2001

In order to evaluate the degradation of pesticides in the water environment, the effects of water temperature, photolysis, pH condition and deactivation of Fenitrothion was investigated in the laboratory experiment. The Fenitrothion was eluded with n-hexan and analysed by FPD-GC. Results showed that the degradation rate increased with water temperature and the Fenitrothion was the most readily decomposable by photolysis. Degradation rate of Fenitrothion by hydrolysis at 30℃ in the buffer solution of pH 3, pH 5, pH 7, pH 9 and pH 11 was 50, 53, 57, 62, 76%, respectively, and the Fenitrothion was unstable in alkaline solution. Fenitrothion was degraded 1.4∼1.8 times faster at 30℃ than at 10℃. Degradation rate of Fenitrothion were 62% under the dark condition and 74% under sunlight at pH 11. Fenitrothion was rapidly degraded at higher Temperature and decomposed faster in the alkaline solution of pH 11 than in the acidic solution of pH 3.