이선영 , 박갑성 Sun Young Lee , Kap Song Park

DOI: Vol.7(No.3) 145-151, 1991

A survey of Volatile Organic Chemicals(VOCs) was conducted in Daegu region public water supplies from Jan. 1990 to July 1990. Five VOCs were detected at quantitiable concentrations. Mean concentration ranges of the VOCs were; trichloroethylene 1.2-3.8㎍/ℓ, carbon tetrachloride 0.1 -0.3㎍/ℓ and tetrachloroethylene trace -0.2 ㎍/ℓ. 1.1.1 -trichloroethane and 1.2 -dichloroethane were detected at trace amount or below the detection limit. Of the Daegu region drinking water samples which were found to be contaminated above the promulgated control limits, 19.4% were contaminated by trichloroethylene and 1.4% by carbon tetrachloride, suggesting that the Daegu region drinking water supplies might be a potential health hazard. The contamination levels of the VOCs from the ground water supplies were higher than those from the surface water supplies.

조광명 , 서정범 Kwang Myeung Cho , Jeong Beom Seo

DOI: Vol.7(No.3) 152-161, 1991

In this study, the characteristics of a small-scale piggery wastewater were investigated, and experiments were performed for the treatability of the waste by using a septic tank soil trench system. Results of the research showed that the average BOD, SS, TKN and TP concentrations of a piggery wastewater were 1,530, 1,236, 562 and 85㎎/ℓ, respectively. The average BOD removal efficiency of the septic tank was determined to be 55% and it was noticed the efficiency was greatly influenced by temperature. It was also found that the average BOD removal efficiencies were 68% for type I soil trench and 78% for type B.

석종혁 , 조광명 Jong Hyuk Seok , Kwang Myeung Cho

DOI: Vol.7(No.3) 162-169, 1991

Leachate from municipal solid waste landfill is an important water pollution source because it contains numerous pollutants in high concentrations. Consequently, it is strongly required to discharge leachate after proper treatment. The purpose of this study was to investigate treatability of leachate from municipal solid waste landfill by activated sludge process. Leachate from a municipal solid waste landfill for Inchon, Korea, located in a coastal reclaimed land, were used for the study. Treatment of settled leachate, supplemented with phosphoric compounds, by a completely-mixed activated sludge process at F/M ratios of 0.1∼0.4g BOD/g MLVSS-day showed SBOD removal efficiencies of 95∼97%. However, poor settleability of the activated sludge caused high SS concentrations in the effluents with a range of 94∼286㎎/ℓ. A rate constant of 0.31ℓ/gMLVSS-hr was computed by analyzing the system assuming a pseudo-first order reaction. Cell yield coefficient and endogenous decay coefficient were computed to be 0.29gMLVSS/gBOD and 0.036/day, respectively by applying the Michaelis-Menten Equation to the system. Oxygen coefficient and endogenous respiration coefficient were also computed to be 0.20㎎ O₂/㎎ BOD and 0.32㎎ O₂/㎎ MLVSS-day, respectively.

김영철 , 최의소 Young Chul Kim , Eui So Choi

DOI: Vol.7(No.3) 170-175, 1991

Autothermal Thermophilic Aerobic Digestion(ATAD) was studied for the treatment of nightsoil by using a laboratory scale completely mixed digester. The operating results indicated the maximum reactor temperature reached to 48℃ at 7d HRT. VS and COD removal efficiencies were respectively 32 to 47% and 26 to 36% with 5 to l0d HRT. The specific energy released during biological reaction was estimated to be 10,500 to 14,000 kj/㎏-COD removed or 18,800 to 25,800 kj/㎏-VS removed. Nitrification was not observed except 20d HRT operated with low temperature. The sludge produced represented poor settling and dewaterbility, however, it showed high pH and low coliform contents which would be more suitable for land application.

원종철 , 남궁완 , 임연택 , 윤조희 Jong Chul Won , Wan NamKoong , Yeon Tack Rim , Cho Hee Yoon

DOI: Vol.7(No.3) 176-184, 1991

The role of trench in soil trench systems treating septic tank effluent was evaluated in the laboratory. Parameters investigated were the waste application method (application with rest period versus continuous application), hydraulic loading rate (100 ℓ/m ·day versus 200ℓ/m day) and soil texture (Sandy Loam versus Sand). Experimental reactors (60㎝ high by 40㎝ wide by 5㎝ thick) were constructed so that two dimensional distribution of bacteria and volatile solids in the trench could be examined. TOC concentrations in the effluent from the reactors with continuous application of wastewater were lower than those from the reactors with rest period. However, the wastewater infiltration rate with continuous application of wastewater was lower than that with rest period implying possible clogging problem in the near future. TOC removal efficiency was over 80% for both systems. TOC concentration in the effluent from the reactor with 200ℓ/m day hydraulic loading rate was much higher than that from the reactor with 100ℓ/m day. The average TOC removal efficiency at 200ℓ/m day was only 63%, while that at 100ℓ/m day was 81%. TOC concentration in the effluent from the reactor packed with sandy loam was similar to that of the reactor packed with sand. Bacteria were high in number near the infiltration surface of wastewater in the trench. Volatile solids were distributed relatively evenly in the trench. There was no direct relationship between the number of bacteria and volatile solids in the soil.

강경희 Kung Hee Kyang

DOI: Vol.7(No.3) 185-192, 1991

The adsorption effects of aromatic chlorocompounds on Granular Activated Carbon were studied in the pH range from 3 to 10. At pH4 the adsorption ability of Granular Activated Carbon for chlorobenzene was most effective among the tested compounds. The comparative value surface diffusiving and pore diffusiving of aromatic chlorocompounds determined by HMN method were Ds/Dp $lt;0.02421 such consequently surface diffusion rate was greater than pore diffusion rate on fact was found control by surface diffusion and also surface diffusivity is the most important design variable. The amount of adsorption on chlorobenzene were 68㎎/g, this change can be tendency on increase concentration and show consider freundlich isotherm equation. The break time and breakthrough curves by constant pattern linear driving force model (cp-LDF model) showed good agreements with the experimental break time (Variation less than 8%) and breakthrough curves.

수등융일 須藤隆一

DOI: Vol.7(No.3) 193-199, 1991