• 한국수자원학회논문집
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• 제41권1호
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• pp.65-74
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• 2008

국내 농업용수 댐은 약 18,000개로 추산되는데 거의 대부분이 월류에 취약한 필댐이다. 여수로 형식은 자연월류 측수로형 여수로가 99%인 것으로 추산되고 있다. 본 연구에서는 댐의 홍수배제능력을 증대시키기 위한 방법의 하나로 측수로형 여수로의 선형웨어 부분을 래버린스 웨어로 개축할 경우 어느 정도의 방류량 증대효과가 발생하는지를 분석하였다. 분석방법은 저수용량 크기별로 5개의 댐을 임의 선정하여 수리모형실험과 Flow-3D를 이용한 3차원수치해석을 통해 월류수심별 방류량을 산정하였고, 확률홍수량과 가능최대홍수량(PMF)에 대한 저수지홍수추적을 실시하여 개축 전 후의 최고수위를 비교하였다. 분석결과 래버린스 웨어는 홍수유입초기에 방류량 증대효과가 있어서 선형웨어에 비해 홍수시 최고수위를 200년 확률홍수량 유입시 13.8$\sim$43.7%, 500년 확률홍수량 유입시 13.9$\sim$38.3%, PMF 유입시 6.1$\sim$9.6% 정도 저하시킬 수 있는 것으로 분석되었다.

• 한국양식학회지
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• 제16권3호
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• pp.142-150
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• 2003

Performance of a biological filter, the rotating biological contactor (RBC), is affected by rotational speed and hydraulic residence time (HRT). A RBC with a disc diameter of 62 cm, total surface area of 48.28 $m^2$, volume of 0.34 ㎥, and submergence ratio of 35.4% was tested for the combinations of five rotational speeds (1, 2, 3, 4 & 5 rpm) and three HRT (0.5, 1.0 & 2.0 hr) to find out the maximum removal efficiencies of total ammonia nitrogen (TAN) and nitrite nitrogen of a simulated recirculating aquaculture system. Ammonia loading rate in the system was 25 g of TAN/ ㎥. day. Removal efficiencies were checked when TAN concentrations in the system stabilized for 3 days in each treatment. The concentration of TAN in the system decreased with increasing rotational speed of the RBC up to 4 rpm in all HRT (P<0.05). At the rotational speed of 5 rpm, the efficiencies decreased in all HRT (P<0.05). When the rotational speeds were 1, 2, 3, 4, and 5 rpm, TAN concentrations in the system were 1.35, 0.94, 0.69, 0.66, and 0.76 mg/L at the 0.5 hr HRT, 2.86, 1.18, 0.96, 0.87, and 1.11 mg/L at the 1.0 hr HRT, and 5.30, 2.44, 1.99, 1.77, and 2.01 mg/L at the 2.0 hr HRT, respectively. The TAN removal efficiencies of the RBC at the rotational speeds of 1, 2, 3, 4, and 5 rpm were 32.9, 49.5, 65.1, 72.9, and 62.9% in 0.5 hr HRT,33.1, 74.1, 87.1, 95.8, and 78.5% in 1.0 hr HRT, and 35.5, 76.7, 89.6, 97.0, and 85.5% in 2.0 hr HRT, respectively. TAN removal efficiency of RBC per pass increased with increasing HRT. However, TAN concentration in the system also increased. The best operating condition among the treatments was obtained at the treatment of 0.5 hr HRT and 4 rpm (P<0.05). The TAN concentration was 0.66 mg/L. Concentrations of nitrite nitrogen (NO$_2$$^{[-10]}$ -N) in the system decreased with increasing rotational speed in all HRT while that in the system increased with increasing HRT in all rotational speeds. The ranges of NO$_2$$^{[-10]}$ -N concentrations at HRT of 0.5, 1.0, and 2.0 hr in the system were 0.26~0.32, 0.31~0.56, and 0.43~l.45 mg/L, respectively. The ranges of daily removal rates of TAN in this system were 20.03~23.0 g TAN/㎥ㆍday and those of nitrite nitrogen were 19.65~30.25 g NO$_2$$^{[-10]}$ -N/㎥ㆍday.