As water resources are limited and legal regulations are strengthened, there is a growing need to reuse residuals in WTP(Water Treatment Plant). In this study, membrane filtration system was constructed and its operation method was studied for water quality stabilization and reuse of WTP residuals. The operation parameters were stable for 1 year and 6 months. Membrane fouling was identified as particulate pollution (activated carbon) and inorganic pollution (manganese). The membrane system was operated steadily with raw water of high concentration SS(Suspended solid) containing activated carbon because membrane fouling was reduced by the effect of End-Free type. In the case of inorganic contamination, dissolved manganese eluted by chemicals and acted as a membrane fouling source, and the operating conditions for minimizing membrane fouling were confirmed by newly developing application methods and types of cleaning chemicals. Based on the results, design parameters for reducing manganese membrane fouling were derived.

무기실리카 입자로 구성된 고탁도 원수를 처리하는 침지식 정밀여과 운전에서 휴민산과 2가 양이온의 존재유무에 따라 시간에 따른 파울링 저항을 관찰하였다. 공기폭기로 인한 무기실리카 입자의 파울링 감소효과는 휴민산과 칼슘이 혼합 으로 존재 시 감소하였다. 파울링층의 전자현미경 관찰결과 칼슘의 존재 시 휴민산의 무기실리카 입자 표면흡착이 관찰되었 다. 이는 멤브레인 표면에 조밀한 파울링층을 형성시켜 공기폭기 효과를 감소시킨 것으로 판단된다. 용액의 조성에 따른 고탁 도 원수의 탁도 제거율에는 큰 변화가 없었으나 공기폭기량에 따라 칼슘과 무기실리카 입자의 혼합 존재 시 유기물질의 제거 율은 80% 이상으로 증가하였다. 이는 공기폭기 하에 무기실리카 입자 표면에 흡착된 일부 휴민산들이 멤브레인 표면으로부 터 함께 역수송 되어 유기물질 제거율을 증가시킨 것으로 사료된다.

담체가 투여된 침지형 막결합 연속회분식 반응기(SMSBR)를 사용한 하수의 고도처리에서 담체가 여과성능과 제 거효율에 미치는 영향을 조사하였다. 담체는 반응기 부피 기준으로 10% 투여하였고, 담체와 분말활성탄을 첨가하지 않은 반 응기, 분말활성탄(10 g/L)만을 첨가한 반응기 및 담체와 분말활성탄을 모두 첨가한 반응기를 대조군으로 하였다. COD, T-N 및 T-P에 대한 제거효율은 담체 및 분말활성탄 첨가 유무에 따라 큰 차이가 없었다. 그러나 담체를 첨가하지 않은 경우 막간 차압(TMP)은 급격히 증가하였으나, 담체를 첨가한 경우에 막간차압은 매우 서서히 증가하였다. 담체를 투여한 SMSBR를 사 용하여 하수를 고도처리 할 때, 91일 이상의 운전기간 동안 막 세정 없이 운전이 가능하였다. 담체만을 투여한 경우, 운전 80 일 경과 이후의 COD, T-N 및 T-P 평균 제거율은 각각 95.0, 69.3% 및 51.4%이었다.

침지식 분리막 모듈에서 공기강도에 따른 분리막 위치에 대한 오염을 조사하였다. 분리막의 충진밀도가 낮은 곳에서 높은 유체 유속을 나타내었으며, 유체 속도는 기-액 주입률에 비례하였다. 전단응력은 기-액 주입률 및 유체 유속에 비례하였다. 비가역오염(Rir)은 흡입 압력이 가까운 부분에서 가장 높게 나타났다(position 1). 비가역오염에 대한 저항과 분리막 고유 저항의 비(Rir/Rm) 및 비가역오염에 대한 저항과 가역오염의 저항의 비(Rir/Rr)도 position 1에서 가장 높게 조사되었다. 비가역오염(Rir)은 흡입 압력이 높은 곳인 position 1에 오염물질이 축적되어진 결과이다. 분리막 위치에 따른 오염현상은 모듈 디자인 최적화에 중요한 인자임을 알았다.

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than 1°C. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was 75°C and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

Various treatment system for residuals have applied to save water resources, but most of them were not be satisfied with legal standard consistently. In this study, submerged membrane treatment system was operated to treat water treatment plant residuals and operation parameters was evaluated. Result of this experiment, high concentration organic matters contributed to high increase Transmembrane pressure(TMP) of membrane system(from 0.05 bar to 0.35 bar). And backwash process was effective to stabilize membrane system operation. After Cleaning-In-Place(CIP), permeability was recovered about 100 % from first operation condition. Inorganic matters (Fe, Mn, Al, Ca, Mg) were not effective membrane filtration performance. The quality of residual treatment was satisfied with drinking water quality standard and a treated water from that system was suitable for water reuse.

The purpose of this experimental research was focused to improve the quality of the effluent and the yielded sludge when the papermill wastewater was treated by the indirect aerated submerged biofilter as a second treatment method of papermill wastewater. Changing the various experimental factors(Nutrient additions or not, HRT, F/M ratio, recirculation ratio, etc) with indirect aerated biofilter, the results obtained are as follows. 1. Because of the microbes concentration could be sustained to $9,000mg/l$ in submerged biofilter and then the volumetric organic loads could be increased to $2.7kg-BOD/m^3/day$(that of activated sludge is $0.8kg-BOD/m^3/day$), the reactor volume can be reduced to one third of the activated sludge treatment. 2. Because of the yield coefficient(Y) and the endogenous decay coefficient(kd) were revealed 0.4 and 0.07/d, the yielded sludge volume was reduced by for compared with that of the activated sludgg process. 3. The concentration of the sloughed sludge in the reactor was 2.62~4.01%, so the thickener could be omitted in the papermill wastewater sludge treatment process. 4. When the operating was conducted at HRT of 4hrs, the treatment efficiencies of BOD and COD were obtained 80% and 70%, Therefore operating time can be reduced to one half of the activated sludge treatment.

This research was performed to examined the applicability of a fixed-biofilm process for the wastewater treatment of military installations. Utilizing plastic net media, synthetic wastewater-average $BOD_5$ cocentration was $192mg/l$ treated in the three sets of reactors that have 8 hours, 6 hours, and 4 hours of hydraulic retention time. The results of this experiment showed that the biofilm was not detached easily, and the reactor was not closed by excess biomass. The average soluble $BOD_5$ concentrations of effluent were $6.0mg/l$ with 8 hours of retention time, $11.3mg/l$ with 6 hours of retention time, and $19.4mg/l$ with 4 hours of retention time. Especially it was reduced to $5.7mg/l$ in the second stage reactor with 4 hours of retention time. These resulted that the fixed-biofilm process could be adapted for the treatment of military installation wastewater.

In this study, it was performed using submerged nonwoven bioreactor(SNBR) for removal of organic matter, nitrogen and phosphate under different aeration intervals(intermittent aeration). We applied the SNBR at the cheap nonwoven fiber module instead of the expensive membrane. The SNBR was mainly made up of an activated sludge reactor and a transverse flow nonwoven module, with an innovative configuration being in application between them. In case of sewage, the aeration conditions experimented consist of continuous aeration and 60min/60min, 120min/60min, 120min/120min of aeration/nonaeration time intervals, respectively. In case of landfill leachate, the intermittent aeration condition was 120min/120min at aeration/nonaeration. Consequently, a high COD removal rate (about 94%) was achieved in sewage and leachate. Although nutrient removal rate was relatively high without any additional chemicals.

The Soysauce wastewater removal characteristics of submerged biofilters filled with two filter media respectively were experimentally examined with constant temperature, pH value and variable BOD loading and recirculation ratio. The decreasing order of BOD removal is Netring(random plastic media), cubic wire meshes(plastic module). This is mainly due to the media characteristics such as void ratio, specific surface area and media shapes. The BOD removal ratio decreases with increasing BOD_5 volumetric loading rate, and the loading rate for the BOD removal over 85% is lower than 1.5㎏BOD_5/㎡d for the plastic media of Netring and cubic wire meshes. The BOD_5 removal rate increases with the recirculation ratio, but the rate of increase become smaller as the recirculation ratio increases over 20. When BOD_5 volumetric loading is 1.5㎏BOD_5/㎡d, the required recirculation ratio to obtain 85% BOD_5 removal is about 20 for Netring and it was about 30 for cubic wire meshes.

This study was conducted to use oyster shell as media for biological wastewater treatment. The comparison between the removal efficiencies of the activated sludge and the submerged biofilm process with oyster shell media (5% of reactor volume) for domestic sewage treatment was made. The contaminant removal efficiencies of the submerged process were higher than that of the activated sludge process. And the removal efficiencies of the submerged biofilm process with oyster shell media of 10% and 18% were investigated at various loading rate. The removal efficiencies of 10% were higher than that of the 18% during the experimental period. The effluent concentration from the submerged biofilm process using oyster shell media was prediceted by the Stover-Kincannon model.

The purpose of this experimental research was focused to improve the quality of the effluent and the yielded sludge when the papermill wastewater was treated by the indirect aerated submerged biofilter as a second treatment method of papermill wastewater. Changing the various experimental factors (Nutrient additions or not, HRT, F/M ratio, recirculation ratio, etc) with indirect aerated submerged biofilter, the results are as follows. 1) Because of the microbes concentration could be sustained to 9,000 ㎎/l in submerged biofilter and then the volumetric organic loads could be increased to 2.7 ㎏-BOD/㎥/day, the reactor volume can be reduced. 2) Because of the yield coefficient(Y) and the endogenous decay coefficient(kd) were revealed 0.4 and 0.07/d, the yielded sludge volume was reduced. 3) The concentration of the sloughed sludge in the reactor was 2.62-4.01 %, so the thickener could be omited in the papermill wastewater sludge treatment process. 4) When the operating was conducted at HRT of 4hrs, the treatment efficiencies of BOD and COD were obtained 80% and 70%. 5) The range of the theoretical recirculation ratios of this reactor was 14-26. According to those ratios, at the low loads ( BOD volumetric loads is less than 0.79㎏-BOD/㎥/day, F/M ratio is less than 2.0/d) the results were fitted to the theoretical recirculation ratios (14∼26) and at the high loads the efficiency were increased to the rise of recirculation ratios.