연구논문 / 오수처리용 인공습지내 토양의 이화학적 특성조사

윤춘경(Chun Gyeong Yoon),권태영(Tae Young Kwun),우선호(Sun Ho Woo) 한국농촌계획학회 1999 농촌계획 Vol.5 No.2

침출수로 오염된 불포화사질토의 전기비저항 변화에 대한 연구

윤춘경 ( Yoon Chun Gyeong ),유찬 ( Yoo Chan ) 한국농공학회 1998 韓國農工學會誌 : 전원과 자원 Vol.40 No.2

Measurement of electrical resistivity in soils has been used for many years with purpose of estimating in situ porosity or density. Recently electrical resistivity has also been used as an indicator of soil contaimination. This paper presents the result of laboratory experiment to investigate the resistivity variation in contaminated sandy soils. The results can be used with the Cone Penetrometer Test (CPT) result to analyse ground condition. In the experiment, the water content and leachate concentration of soils were controlled by groundwater and leachate, and then the resistivity measurement was made with 'STING-R1' by Advanced Geosciences Inc. In the case of using groundwater, the resistivity was in the range of over 1000·Ωm, but in the case of using polluted water by leachate, the resistivity decreased significantly down to 10~100·Ωm for the same moisture content. Also the resistivity varied according to the degree of saturatrion. Therefore, if soil is contaminated by leachate, the CPT with electrical resistivity sensor might be used to investigate the contamination status and plume migration. But exact component of leachate and the pollutant concentration are still hard to identify.

유기화합물들이 혼합상태에서 토양에 흡착하는 성질에 관한 연구

윤춘경 ( Yoon Chun Gyeong ) 한국농공학회 1995 韓國農工學會誌 : 전원과 자원 Vol.37 No.2

혼합상태에서 유기화합물들이 토양에 흡착하는 성질에 관해서 5개의 유기화합물(페놀, 2,4-디크로로페놀, 2,4,6-트리크로로페놀, 부루신, 따이오유리아)과 2종류의 토양을 이용하여 연구하였다. 일반적으로 따이오유리아를 제외하고는 한가지 물질이 혼합상태에 있는 다른물질에 의해 흡착에 제약을 받아서 단독으로 있을 때 보다 흡착율이 낮았다. 따이오유리아는 단독인 경우보다 혼합상태일 때 더 많은 흡착을 보였는데 이는 혼합상태에서 오히려 흡착이 증가 할 수도 있음을 나타낸다. 혼합이 흡착에 미치는 영향은 페놀의 혼합상태와 단독상태에서의 흡착상태를 여러가지 형태로 비교하며 검토하였는데 산성이고 유기물질이 적은 토양에서 알카리성이며 유기물질이 많은 토양보다 혼합으로 인한 흡착의 억제효과가 뚜렷하였다.

TDR을 이용한 토양함수비 측정의 정확성에 대한 실험

윤춘경 ( Yoon Chun Gyeong ),유찬 ( Yu Chan ),김경한 ( Kim Kyoung Han ) 한국농공학회 1999 韓國農工學會誌 : 전원과 자원 Vol.41 No.1

Laboratory experiment was performed for the TDR to measure the soil moisture, and the results, were compared with the design water content and the one measured by oven-try method. Sand and kaolinite were used. Variables for the experiment were water content (10~50%), void ration (0.7~1.3), mixture rate of kaolinite (10~30%), and measurement methods (TDR and oven-dry). In all cases, TDR method showed very accurate and reliable results, and average error and error range were far less than the oven-dry method which is widely used. Considerable error was noticed when water content was 50% where saturation was achieved for both methods. Therefore, TDR was thought to be applicable to the field moisture measurement if it is unsaturated. For field scale application of TDR, more research and verification of the accuracy with diverse soil conditions including physical, chemical and mineral properties are recommended.

생장기와 동절기의 인공습지 오수처리 성능

윤춘경 ( Yoon Chun Gyeong ),권순국 ( Kwun Soon Kuk ),함종화 ( Ham Jong Hwa ) 한국농공학회 1999 韓國農工學會誌 : 전원과 자원 Vol.41 No.4

Field experiment of constructed wetland for rural wastewater treatment was performed from July 1998 to April 1999 including winter to examine the seasonal effect on the wetland performance. The system worked without freezing even under -10℃ of air temperature as long as wastewater was flowing. BOD removal rates varied in similar pattern as the air temperature, and winter performance was relatively lower than that in the growing season. However, removing performance during winter was still significant, and BOD removal rates were almost the same as in the growing season. SS removal rate was relatively less affected by temperature, but lower decay rate during the winter can result in accumulation of the SS in the system, which releases constituents in the next spring and can affect whole system performance. The winter removal rates of nutrients like T-N and T-P were decreased about half compared to the growing season and low temperature. To maintain stabilized wetland performance including winter time, supplying minimum heating for plants could be an alternative in field application. Experimental data was compared with NADB (North American Wetlands for Water Quality treatment database), and general performance of the system was within the reasonable range. The pollutant loading and effluent concentration of the experimented system were in high margin. Base on the experiment and databases, the required effluent water quality could be achieved if loading rate adjusted as illustrated in the database.

강물의 수질오염 Modeling에 사용되는 신뢰도 분석방법에 대한 비교연구

윤춘경 ( Yoon Chun Gyeong ) 한국농공학회 1995 韓國農工學會誌 : 전원과 자원 Vol.37 No.5

공학분야에 널리 사용되고 있는 신뢰도 분석방법중에서 Monte Carlo simulation (MC), Mean-value First-Order Second-Moment Method(MFOSM), and Advanced First-Order Second-Moment(AFOSM) method들을 강물의 오염물질 농도와 수질기준치사이의 신뢰도 분석에 적용하였다. 미환경보건국에서 개발 보급한 QUAL2E를 이용하여 New Jersey에 위치한 Passaic강의 수질예측에서 4가지 주요인자(용존산소, 생물학적 산소요구량, 암모니아 그리고 조류)들이 정해진 수질기준치를 유지 할 수 있는 확률을 세가지 방법에 의해 추정한 후에 상호 비교하였다. MC방법에 의해 2,000회 simulation시켜서 그 결과가 시스템의 추계학적 성질을 잘 반영한 것으로 판단하여 비교기준으로 삼고 MFOSM과 AFOSM에 의해 추정한 결과와 비교하였다. MFOSM의 결과보다는 AFOSM의 결과가 전체적으로 MC의 결과에 더 근접하였으며, 이유는 AFOSM의 계산방법이 MFOSM의 선형근사로 인한 오차를 줄일 수 있었기 때문인 것으로 판단된다. MC방법의 결과와 다른 방법들의 결과사이의 차이가 입력변수들이 평균값에서 멀어질 때가 많았는데 이는 MC의 경우 입력변수들이 일정범위를 벗어나서 비현실적인 상황이면 model이 정지하는데, 다른 방법들은 simulation에 의한 것이 아니고 수학적인 계산에 의해서 신뢰도가 추정되기 때문에 이러한 상황이 반영될 수 없기 때문이다. 강물의 수질을 취급하는 공학적인 측면에서 보면, 이중에 가장 간편한 MFOSM이 많은 simulation이 필요한 MC나 계산방법이 상대적으로 복잡한 AFOSM에 비해 오차가 크지 않아서 이들을 대신하여 사용될 수 있다고 판단된다.

인공습지에 의한 농촌오수처리에 관한 연구

윤춘경 ( Yoon Chun Gyeong ),권순국 ( Kwun Sun Kook ),김형중 ( Kim Hyung Joong ) 한국농공학회 1997 韓國農工學會誌 : 전원과 자원 Vol.39 No.4

Constructed wetland system which can be applied to the rural wastewater treatment system was examined by pilot plant in Kon-Kuk University. Hydraulic loading rate of wastewater was about 0.16m³/m² · day and theoretical detention time in the system was 1.38 days. The effluent of the septic tank for the school building was applied as inflow to the system. The influent concentration of DO was zero but effluent was up to 4.37mg/ℓ, which implies that oxygen was supplied enough from atmosphere by reaeration to support biological activity of the system. Average influent concentration of BOD was 104mg/ℓ and effluent was 24mg/ℓ with average removal rate of 76%. Average influent concentration of COD was 215mg/ℓ and effluent was 63mg/ℓ with average removal rate of 70%. Average influent concentration of SS was 78mg/ℓ and effluent was 10mg/ℓ with average removal rate of 87%. Two components, BOD and SS, are regulated by law to keep maximum water quality standard of 80mg/ℓ when daily outflow rate is less than 100m³/day which is the case of most rural communities. Therefore, the results from the experiment showed that constructed wetland system can meet the water quality standard easily. Average influent concentration of total nitrogen was 165mg/ℓ which is relatively higher than normal wastewater, and effluent was about 156mg/ℓ with average removal rate of only 5%. Average influent concentration of total phosphorus was 41mg/ℓ and effluent was 6mg/ℓ with average removal rate of 87%. Overall, constructed wetland system was thought to be effective to treat wastewater if nitrogen removal mechanism is improved. Considering low cost, less maintenance, and high treatability, this system can be a practical alternative for the wastewater treatment in rural area. The Experiment was performed during the summer and fall season, and treat ment efficiency of the system is expected to decrease in low temperature. Therefore, further study including temperature is required to evaluate feasibility of the system more in detail.

습지-저류지에 의한 하구 담수호 수질개선 효과 예측

윤춘경 ( Yoon Chun Gyeong ),함종화 ( Ham Jong Hwa ) 한국농공학회 2000 韓國農工學會誌 : 전원과 자원 Vol.42 No.5

Investigated was the effectiveness of a constructed wetland system on water quality in Hwa-Ong estuarine reservoir, located in Hwasung-Gun, Kyunggi-Do. Procedures for estimation of pollutant loading from watershed and required area for natural systems, and simulation of corresponding reservoir water quality were reviewed. Generally, simulated reservoir water quality was within the reasonable range, and about 15% of total polder farmland was required to meet the agricultural water quality standards. The model was applied based on the current loading condition without additional treatment systems. Wetland system is an ecologically sound treatment system. Therefore, natural systems can be an alternative measure for water quality improvement in polder projects. The area for natural systems was estimated using literature value which might be acceptable at the planning stage. However, pilot system and its experimental data are requisite for large scale field application. WASP5 was proved to be a useful and versatile model, and its application to estuarine reservoir water quality simulation was thought to be appropriate.

강물의 수질오염 modeling에 사용되는 재폭기(再曝氣)계수공식 개발을 위한 적정규모의 표본의 크기

윤춘경 ( Yoon Chun Gyeong ),( Charles S. Melching ) 한국농공학회 1996 韓國農工學會誌 : 전원과 자원 Vol.38 No.4

동일한 하천의 용전산소량(DO)을 예측하는 경우에도 사용하는 再曝氣 계수(K₂)는 계산하는 공식에 따라 커다란 차이를 나타매며, 부적합한 공식의 사용에 의한 K₂의 계산은 하천의 수질관리 정책결정에 지장을 초래하므로 현장사정에 적합한 공식의 개발이 필요하다. 이러한 공식의 개발은 많은 현장측정 자료를 사용하도록 신뢰성이 높으나 현장측정은 소요되는 비용에 제약을 받기 때문에 신뢰성과 경제성을 동시에 고려한 표본의 크기의 적정규모를 산정하는 것이 필요하다. 본 연구에서는 Monte Carlo 방법에 의해 통계적으로 수출된 K₂를 사용해서, 주어진 자료에 의해 개발된 공식을 사용할 때 야기되는 오차가 K₂ 개수의 증가에 따라 얼마나 감소하는지를 널리 사용되는 공식 중에 Owen공식과 Churchill공식을 New Jersey에 있는 Passaic River에 적용시켜 검토하였다. 표본의 크기가 10에서 20으로 증가할 때 오차가 크게 감소하였으며 20을 넘어 증가시켰을 때에는 오차의 감소폭이 미미하였다. 오차의 감호형태와 단위측정당 소요되는 비용을 고려할 때 약 20정도의 표본의 크기가 적정수준의 규모에 판단된다. 이러한 적용사례의 결과는 회귀모델의 이론적 계산결과에 의한 오차 감소와 흡사하여 본 연구결과는 여러 가지 K₂ 공식과 광범위한 하천의 조건에 적용이 가능할 것이며, 본 연구에서 사용한 적정표본의 크기 산정방법은 회귀분석에 의해 실험식을 개발하는 다른 분야에도 적용이 가능하다.

오수처리수 관개 벼재배를 통한 농업용수 수질기준의 검토

윤춘경 ( Yoon Chun Gyeong ),권순국 ( Kwun Soon Kuk ),정일민 ( Chung Il Min ),권태영 ( Kwon Tae Young ) 한국농공학회 1999 韓國農工學會誌 : 전원과 자원 Vol.41 No.2

Agricultural water quality standards were reviewed through rice culture using treated sewage irrigation. The sewage from school building of Konkuk University was treated by a constructed wetland system, and the effluent of the system was irrigated for rice culture after nutrient concentration adjusted by dilution. Average concentration of COD, SS, T-N and T-P in irrigated water was 22.3mg/ ℓ, 6.5mg/ ℓ, 25.8mg/ ℓ, and 2.2mg/ ℓ, respectively. Treatment include irrigation of adjusted effluent with conventional fertilization (TWCF), adjusted effluent with no fertilization (TWNF). and effluent of the wetland system as it was with no fertilization (SWNF). These treatment plots were compared with control plot irrigated by tap water with conventional fertilization (CONTROL). Other environments for rice culture were identical for all the plots. Among them, TWCF showed the best growth rate and the highest yield, and constituents in the harvested rice showed not much difference among them. Which implies that irrigation with relatively high nutrient concentration compared to the current water quality standards may cause no adverse effect on rice culture and could be even beneficial. Although T-N for this study was 25 times greater than the current standards, rice culture was not adversely affected by irrigation water quality and even better results were observed than the CONTROL. It could be mistakenly that clean irrigation water produces better agricultural product, however, it is not necessarily true. Irrigation water with moderate nutrient concentration can enhance the plant growth, and better result might be expected. Therefore, peer review and modification if necessary are needed to the current agricultural water quality standards, especially for the nutrient components.