Fuzzy algorithm of automatic control for dissolved oxygen(DO) concentration in the aeration tank of an activated sludge process is proposed. Among variables repirometry and air flowrate are selected as significant input factors and the relationship with DO is estimated using a multiple regression model. The DO concentration and the amount of repirometry are fuzzified and the fuzzy rule base are determined. Using the fuzzy algorithm, the change of amount of air flowrate are determined and the change of amount of DO is derived.

The transfer function was introduced to establish the prediction method for the DO concentration at the intaking point of Kongju Water Works System. In the most cases we analyze a single time series without explicitly using information contained in the related time series. In many forecasting situations, other events will systematically influence the series to be forecasted(the dependent variables), and therefore, there is need to go beyond a univariate forecasting model. Thus, we must build a forecasting model that incorporates more than one time series and introduces explicitly the dynamic characteristics of the system. Such a model is called a multiple time series model or transfer function model. The purpose of this study is to develop the stochastic stream water quality model for the intaking station of Kongju city waterworks in Keum river system. The performance of the multiplicative ARIMA model and the transfer function noise model were examined through comparisons between the historical and generated monthly dissolved oxygen series. The result reveal that the transfer function noise model lead to the improved accuracy.

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated sludge and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floc. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floc. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0㎎/ℓ to 258 ㎎/ℓ. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about 100m in this study.

캘리포니아 담수직파재배용 품종인 L-202, M-202, S-201, Italiconaverneco와 한국의 화성별르 공시히여 25℃ 의 수온하에서 용존산소의 흡수 양상과 발아특성을 조사한 결과는 다음과 같다. 1. 벼 품종들의 침종후 용존산소흡수의 경시적 변화를 보면 침종 1일부터 Italiconaverneco가 가장 왕성히 흡수하였고 다음이, S-201, 화성벼, L-202, M-2-202 순이었다. 2. 초엽과 종자근이 완전히 출현한 침종 4일후의 과적 용존산소 흡수률은 Italiconaverneco 볍씨 1개가 211.7ug 을 흡수하였고 S-201이 179.5ug , 화성벼는 144.3ug , L-202와 M-202는 각각 140.4, 135.8ug 이었다. 3. 초엽의 출현율은 Italiconaverneco와 L-202가 가장 높았고 다음이 M-202, S-201이 었으며 화성벼가 가장 낮았다. 4. 종자근의 출현율은 Italiconaverneco가 가장 높았고 다음이 S-201, 화성벼, L-202, M-202 순으로 낮았다. 5. 초엽과 종자근의 길이는 Italiconaverneco가 월등하게 길었고 다음이 S-201, 화성벼이었고 L-202와 M-202가 가장 짧았다.

담수 직파 재배시 벼 종자의 발아에 필요한 산소요구도 및 발아 특성을 검토하기 위하여 Japonica 형과 Ind. Jap. 품종을 공시하여 25℃ 와 17℃ 의 수온하에서 시험한 결과를 요약하면 다음과 같다. 1. 25℃ 및 17℃ 의 수온에서 침종후 용존산소 흡수 및 흡수속도는 Japonica 형인 낙동벼가 Ind. Jap. 형인 삼강벼에 비하여 컸다. 2. 수분흡수는 침종 2일까지는 품종간 차이가 작았으나 3일후부터 현저한 차이를 나타내어 낙동벼가 보다 더 많이 흡수하였다. 3. 침종후(25℃ 수온) 3일까지의 발아율 및 용존산소 흡수량은 Japonica 형 품종들이 Ind. Jap. 형 품종들보다 높았다. 4. 발아 및 종자근의 출현까지 25℃ 의 수온하에서 Japonica 형 품종들은 각각 3, 4일 Ind. Jap.형 품종들은 각각 4, 5일이 소요되었으며 Japonica 품종들이 Ind. Jap.형 품종들 보다 용존산소의 총흡수량이 적어서 발아시 산소요구도가 낮았다. 5. 침종 5일후의 초엽장, 종자근장, 발아율은 Japonica 형 품종들이 Ind. Jap.형 품종들보다 현저하게 컸다.