This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/ Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 ㎏BOD/㎥/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater. Conclusions of this study were as follows: 1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anaerobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter. 2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1㎎/cycle, and that of BOD consumed were 10-40㎎/cycle. 3) For P removal of mixed wastewater, EBPR appeared only Mode 3(3*). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 ㎎/L. It was caused to a large amount of ICOD in influent. However, as P concentration in influent was increased, the amounts of P release and uptake were increased linearly.

The sewage sludges and livestock manures, respectively, were composted with sawdust used for control moisture in the static piles system composter. The variations of temperature, pH, moisture, C/N ratio, inorganic content, forms of organic materials and nitrogen, and contents of heavy metals were investigated. The results were summarized as follows ; The temperature for composting the sewage sludges reached the highest temperature of 52℃, after 3 days and lasted for 7 days, and then went down 30℃ after 52 days. In the case of composting livestock manures, the temperature reached to 63℃ after 10 days, that lasted for 10 days, and then went down gradually. After upsetting the sewage sludges and livestock manures, the temperature went up but was little changed after 52 days. Thus we decided that the terminal of composting periods would be 52 days. The moisture contents of the sludges and livestock manures for composting were decreased to 30% and 36%, respectively. The contents of inorganic matters and heavy metals were changed by the characteristics of raw materials but increased gradually during composting process. The total contents of organic materials in the sewage sludges and livestock manures for composting were decreased to 7% and 9%, respectively. The contents of ether extracts, resins, hemicellulose and cellulose were decreased but those of water soluble polysaccharides and lignins were not changed. The total contents of nitrogen in sewage sludges and livestock manures were decreased to 43% and 34%, respectively.

This paper describes the working of algal culture system under batch and continuous feeding effluents in biological treatment process. The main objective of this study was the determination of fundamental operating parameters such as dilution rates, light intensity, biomass concentration, nutrients contents, which engender an effective nutrient and organic waste removal process. The results of this research indicate that the algae system will remove effectively nutrient and organic waste. In batch cultures, 91.8% dissolved orthophosphate and 83.3% ammonia nitrogen were removed from the sewage in ten days. In continuous flow systems, a detention time of 2.5 days was found adequate to remove 91% T-P, 87% T-N and 95% NH3-N. At 22-28℃, 60 rpm, with an intensity of 3500 Lux, the specific growth rate, k was 0.59/day in batch experiments. The optimal growth temperature and nutrients rate (N/P) were respectively 25℃ and 3∼5. With an abundant supply of nutrients, it was possible to sustain substantial population densities in the temperature range of 22∼28℃.

한수관내 침전물의 퇴적을 방지하기 위하여는 최저유속과 에너지경사, 관경을 산정하여 제시하여야 되는데 이들 수치를 바로 결정하는 양해법 산정식들을 개발하였다. 이를 위하여 토사의 임계전단력과 상용관 마찰계수 산정을 위하여 지수형 산정식들을 도입하였으며, 이들 지수형 산정식들은 기존 실험관측자료를 이용하여 개발되었다. 제시된 수치들의 적합성을 판별하기 위하여 여러 예들을 본 연구에서 개발된 산정식들을 적용하여 검토하였다.

수영하수처리장 방류수의 해중방류법과 3차 처리 시설 설치의 비용분석을 한 결과는 다음과 같다. 1) 해안에서 4km 거리와 관경을 2m의 해중방류법을 이용한 수용만의 수질을 개선시키는데 소요되는 해중방류관 건설비용은 383억 원이 소요되는 것으로 산출되었다. 2) 수영하수처리장의 유출수를 해중방류관을 통해서 방류할 경우 방류수심을 32m, Diffuser의 길이를 200m로 할 경우의 초기희석배율은 유속에 따라서 56.4∼399.2으로 계산되었다. 3) 질소를 제거하기 위한 순환법의 경우의 20년 동안의 총 비용은 1,364억 원, 인을 제거하기 위한 응집제 첨가 활성슬러지법은 1,010억 원, 해중방류법은 383억 원으로 해중방류법이 3차 처리시설을 설치하는 비용보다 약 2.6∼3.5배 비용을 적게 소요하는 것으로 산출되었다. 4) 해중방류법을 이용할 경우의 수영만의 수질영향을 예측하기 위해서 물질순환모델을 이용하여 예측한 결과 수영만의 수질이 COD, 용존무기질소(DIN)와 용존무기인(DIP)의 전 항목에서 해역환경 II등급을 만족하는 것으로 예측되었다.

A new biological nutrient removal system combining A2/O process with fixed film was developed in this work and the characteristics of denitrifcation were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of NOx-N, COD, DO and nitrite effects on NOx-N removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40%/30%/25% based on its reactor volume, respectively. It was found that COD rarely limited denitrification in the anoxic reactor because of high C/NOx-N ratio in the anoxic reactor, while DO concentration in the anoxic reactor and NO2-N/NOx-N from the aerobic effluent inhibited denitrifcation in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and NO2-N/NOx-N from the aerobic effluent were 0.15㎎/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and NO2-N/NOx-N from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and NO2-N/NOx-N from the aerobic effluent exceeded the critical points of 0.15㎎/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and NO2-N/NOx-N from the aerobic effluent can assure effective denitrifcation.

We examined whether several reeds, which are found around Ulsan area, could be used for downflow reed-bed to remove pollutants of sewage. Three kinds of reed, such as Phagmites australis, Typha orientalls, and Phalaris aundinacea L., were collected from their habitats near the Taehwa River in Ulsan City. In the minimized model system of downflow reed-bed, P. australis appeared to reduce BOD more than others did but slightly increase total amount of nitrogen(N). When P. australis were placed in the sterilized water, total nitrogen was found to be significantly increased dependent on the number of experimental plant in the sterilized state, but it was rather decreased in the non-sterilized state. With these results, microorganisms attached to P.australis roots can be thought to work for removal of pollutants. Therefore, these microorganisms and their habitat, P. australis reed bed, together can be used for sewage treatment. It was suggested that oxygen is produced by photosynthesis reaction of P. austrails. The increased oxygen may help microorganisms in their habitats to work on the removal of pollutants