As aeration is an energy-intensive process, its control has become more important to save energy and to meet strict effluent limits. In this study, predictive aeration control based on the respirometric method has been applied to the sequencing batch reactor (SBR) process. The variation of the respiration rate by nitrification was great and obvious, so it could be a very useful parameter for the predictive aeration control. The maximum respiration rate due to nitrification was about 60 mg O2/L‧h and the maximum specific nitrification rate was about 7.5 mg N/g MLVSS‧h. The aeration time of the following cycle of the SBR was daily adjusted in proportion to that which was previously determined based on the sudden decrease of respiration rate at the end of nitrification in the respirometer. The aeration time required for nitrification could be effectively predicted and it was closely related to influent nitrogen loadings. By the predictive aeration control the aerobic period of the SBR has been optimized, and energy saving and enhanced nitrogen removal could be obtained.

Recent focus on wastewater treatment includes energy-saving and renewable energy generation for energy-independence of water infrastructures. Aeration and pumping in biological wastewater removal processes account for nearly 30-60% of the total electricity cost in real wastewater treatment plants. In this study, the performance and microbial characteristics were investigated in sequencing batch reactor under typical oxygen and oxygen limited condition. Under typical DO (7.55±0.99 mg/L) and low DO (0.23±0.08 mg/L) conditions, COD removal was stable over 91 % during SBR operation. Ammonia removal efficiency was reduced from 95.6 % to 89.2 % when DO concentration was dropped sharply. Phosphorus removal efficiency also reached 77% at oxygen-limited condition. The results indicated that removal efficiency both ammonia and phosphorus was influenced by DO condition. Microbial analysis revealed that Proteobacteria and Bacteroidetes at phylum level was dominant in typical DO and low DO conditions and DO concentration did not much affect phylum distribution. Population decrease of genera of nitrifying bacteria(Dokdonella) and Dechloromonas spp. affect removal efficiency of nitrogen and phosphorus at low DO condition.

The respirometric technique has been used to analyze the nitrification process in a sequencing batch reactor(SBR) treating municipal wastewater. Especially the profile of the respiration rate very well expressed the reaction characteristics of nitrification. As the nitrification process required a significant amount of oxygen for nitrogen oxidation, the respiration rate due to nitrification was high. The maximum nitrification respiration rate, which was about 50 mg O2/L･h under the period of sufficient nitrification, was related directly to the nitrification reaction rate and showed the nitrifiers activity. The growth rate of nitrifiers is the most critical parameter in the design of the biological nutrient removal systems. On the basis of nitrification kinetics, the maximum specific growth rate of nitrifiers in the SBR was estimated as 0.91 d-1 at 20℃, and the active biomass of nitrifiers was calculated as 23 mg VSS/L and it was about 2% of total biomass.

As the sequencing batch reactor process is a time-oriented system, it has advantages of the flexibility in operation for the biological nutrient removal. Because the sequencing batch reactor is operated in a batch system, respiration rate is more sensitive and obvious than in a continuous system. The variation of respiration rate in the process well represented the characteristics of biological reactions, especially nitrification. The respiration rate dropped rapidly and greatly with the completion of nitrification, and the maximum respiration rate of nitrification showed the activity of nitrifiers. This study suggested a strategy to control the aeration of the sequencing batch reactor based on respirometry. Aeration time of the optimal aerobic period required for nitrification was daily adjusted according to the dynamics of respiration rate. The aeration time was mainly correlated with influent nitrogen loadings. The anoxic period was extended through aeration control facilitating a longer endogenous denitrification reaction time. By respirometric aeration control in the sequencing batch reactor, energy saving and process performance improvement could be achieved.

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.

C/N 비가 낮은 농촌마을 하수의 고도처리를 위하여 0.4 µm의 세공크기를 갖고 있는 평막이 침지된 연속회분식 반응기를 사용하였다. 분말활성탄의 투입, 폭기량 및 유입 유기물 농도가 처리효율과 여과 성능에 미치는 영향을 조사하였다.54일 이내의 조업 초기에서는 C/N 비가 증가할수록 COD, T-N 및 T-P의 제거율과 MLSS 농도는 증가하였다. 조업 89일 후의 COD, T-N 및 T-P의 제거율은 각각 97.1%, 75.0% 및 48.3%이었다. 막여과에 의해 처리수에서 SS는 검출되지 않았으며,T-P의 제거율이 낮게 나온 이유는 과잉의 슬러지를 배출하지 않았기 때문이다. 분말활성탄을 투여한 경우 조업이 진행됨에따라 분말활성탄의 혼합강도와 충돌빈도가 증가하여 슬러지의 입자크기가 감소하였으며, 이로 인해 분말활성탄을 투여하지 않은 경우에 비해 TMP 상승이 크게 나타났다.

스펀지 형태의 담체가 첨가된 침지형 막결합 연속회분식 생물반응기에서 담체가 제거효율과 여과성능에 미치는 영향을 조사하였다. 담체는 반응기 부피 기준으로 각각 5%, 10% 및 20% 첨가하였고, 담체를 첨가하지 않은 반응기를 대조군으로 하였다. COD, T-N 및 T-P에 대한 제거효율은 담체 첨가 유무에 관계없이 큰 차이가 없었다. 그러나 담체를 첨가한 경우, 첨가하지 않은 경우에 비해 조업시간에 따른 막간차압(TMP)은 매우 서서히 증가하였다. 이러한 결과는 폭기에 의해 상승하는 담체가 막 표면과 충돌하게 되고, 이때 막 표면에 형성된 케이크 층을 제거시키기 때문이다. 결론적으로 담체가 첨가된 막결합형 연속회분식 생물반응기는 담체가 없는 반응기에 비해 여과성능이 크게 개선되어, 폐수처리에 효과적으로 활용될 수 있을 것이다.

침지식 막결합형 연속회분식 생물반응기에서 폐수의 도입단계가 제거효율과 여과성능에 미치는 영향을 조사하였다. 호기성 단계의 초기에 공급할 경우(Mode-1)와 무산소 단계의 초기에 공급할 경우(Mode-2)에 대하여 89일 동안 동시에 운전하였다. COD 제거효율과 여과성능은 2가지 운전방식 간에 큰 차이가 없었다. 그러나 영양염류(총질소와 총인)의 제거효율에 있어서 Mode-2가 Mode-1에 비해 보다 효과적이었다. Mode-2의 경우 COD, 총질소 및 총인의 제거율은 각각 99.1, 73.3 및 77.7%이었다.

0.4μm의 세공크기를 갖고 있는 평막이 침지된 연속회분식 반응기에서 유입 유기물 농도가 영양염류 제거에 미치는 영향을 조사하였다. 분리막의 여과성능과 영양염류 제거효과를 규명하기 위하여 유입 유기물의 농도를 200 mg/L (Run-1), 400 mg/L (Run-2) 및 800 mg/L (Run-3)로 연속적으로 변화시키면서 실험하였다. COD/N 및 COD/P의 비가 증가할수록 T-N 및 T-P의 제거율은 모두 증가하였다. Run-1, Run-2 및 Run-3에서 T-N의 평균 제거율은 각각 28.1, 32.6 및 90.4%이었으며, 투과수의 T-N 평균 농도는 각각 32.0, 30.0 및 4.3 mg/L 이었다. 또한 Run-1, Run-2 및 Run-3에서 T-P의 평균 제거율은 각각 13.6, 35.3 및 93.1%이었으며, 투과수의 T-P 평균 농도는 각각 3.11, 2.33 및 0.25 mg/L이었다.

This research investigated efficient operation mode for the successful performance of SBR(sequencing batch reactor) treating fish processing wastewater, and the effect of sodium chloride (NaCl) on treatment efficiency. 2-hour-annerobic, 6-hour-aerobic and 3-hour-anoxic operation during reaction period was found an effective operating method for organic and nitrogen removal from fish processing wastewater in SBR system. The average removal efficiencies of COD, BOD, and total nitrogen in SBR operated continuousely were 91%, 95%, and 67.1%, respectively. The estimated values of biomass yield coefficient(Y), microbial decay coefficient($K_d$), and bioreaction rate constant(K) were $0.35gMLSS/gCOD_{removed}$, $0.015day^{-1}$, and $0.209hr^{-1}$, respectively. As NaCl concentration increased from 5 to 30g/L, sludge settleability was cnhanced but organic removal in the reactor was decreased. NaCl of influent had considerable relationship with COD removal, whereas it did not significant affect nitrogen removal.

The purpose of this study was to evaluate the operational characteristics of wastewater treatment using Sequencing Batch Reactor (SBR) with Aerobic Granular Sludge (AGS) separator in the pilot plant. Pilot plant experiments were conducted using SBR with AGS separator and pollution removal efficiencies were evaluated based on the operational condition and surface properties of AGS. The results of the operation on water quality of the effluent showed that the average concentration of total organic carbon, suspended solids, nitrogen, and phosphorus was 6.89 mg/L, 7.33 mg/L, 7.33 mg/L, and 0.2 mg/L, respectively. All these concentrations complied the effluent standard in Korea. The concentration of mixed liquor suspended solid (MLSS) fluctuated, but the AGS/MLSS ratio was constant at 86.5±1.3%. Although the AGS/MLSS ratio was constant, sludge volume index improved. These results suggested that the particle discharged fine sludge and increased the AGS praticle size in the AGS. Optical microscopy revealed the presence of dense AGS at the end of the operation, and particles of > 0.6 mm were found. Compared to those of belt-type AGS separator, the required area and power consumption of the hydrocyclone-type AGS separator were reduced by 27.5% and 83.8%, respectively.

This study aimed to evaluate changes in the TN and TP removal efficiencies, depending on whether or not a settling process is applied, in a sequencing batch reactor (SBR) process with a membrane bioreactor (MBR). Nutrient removal was considered in terms of developing an advanced water treatment system for ships in accordance with water quality standards set forth by 227(64). For these purposes, the TN and TP concentrations in the inflow and outflow water were measured to calculate the TN and TP removal efficiencies, depending on whether or not a settling process was used. Water discharged from a bathroom, which was constructed for the experiment, was used as the raw water. The experiment that included a settling process was conducted twice, and the operating conditions were: aeration for 90 min, settling for 30 min, agitation for 15 min, and settling for 15 min for one experiment; and aeration for 150 min, settling for 45 min, agitation for 15 min, and settling for 15 min in the other. Operating conditions for the experiment that did not include a settling process were: aeration for 180 min and agitation for 60 min. The concentration of the mixed liquor suspended solids (MLSS) in the reactor was 3,500 mg/L, while the aeration rate was 121 L/min and the water production rate was 1.5 L/min. For the two experiments where a settling process was applied, the average TN removal efficiencies were 44.39% and 41.05%, and the average TP removal efficiencies were 47.85% and 46.04%. For the experiment in which a settling process was not applied, the average TN removal efficiency was 65.51%, and the average TP removal efficiency was 52.51%. Although the final nutrient levels did not satisfy the water quality standards of MEPC 227(64), the TN and TP removal efficiencies were higher when a settling process was not applied.

The biological wastewater treatment plant, which uses microbial community to remove organic matter and nutrients in wastewater, is known as its nonlinear behavior and uncertainty to operate. Therefore, operation of the biological wastewater treatment process much depends on observation and knowledge of operators. The manual inspection of human operators is essential to manage the process properly, however, it is impossible to detect a fault promptly so that the process can be exposed to improper condition not securing safe effluent quality. Among various process faults, equipment malfunction is critical to maintain normal operational state. To detect equipment faults automatically, the dynamic time warping was tested using on-line oxidation-reduction potential (ORP) and dissolved oxygen (DO) profiles in a sequencing batch reactor (SBR), which is a type of wastewater treatment process. After one cycle profiles of ORP and DO were measured and stored, they were warped to the template profiles which were prepared already and the distance result, accumulated distance (D) values were calculated. If the D values were increased significantly, some kinds of faults could be detected and an alarm could be sent to the operator. By this way, it seems to be possible to make an early detecting of process faults.

The effect of the variation of aeration time on the microorganisms was investigated in sequencing batch reactor (SBRs). The cycling time in four SBRs was adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. As the increase of aeration time, the consumption of glycogen within sludge at the 1st non-aeration time a little bit was increased and the production of glycogen at the aeration time was increased. Also, the produced PHB amounts and PHB production rate at the 1st non-aeration time were increased as the decrease of aeration time, which showed the activation of the phosphorus removal. The ratios of nitrifying microorganisms' number and GAOs to the total microorganisms' number in SBRs was decreased as the decrease of the aeration time, however, the PAOs ratio was almost constant irrespective of the variation of aeration time.

The effect of the variation of aeration time on the removal of organics, nitrogen and phosphorus using synthetic wastewater was investigated in sequencing batch reactors (SBRs) which included DNPAOs and DNGAOs. The cycling times in four SBRs were adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. Average TOC removal efficiencies were about 71 % in all SBRs. The NH_4^+-N removal efficiency was increased as the increase of aeration time. After changing aeration time, the total nitrogen removal efficiencies of SBRs were shown as 35 %, 85 %, 75 % and 65 %, respectively. Higher phosphorus release and uptake were occurred as the decrease of the aeration time. After all, the overall phosphorus removal efficiency decreased and the deterioration of phosphorus removal was occurred when aeration time was over 4 hr. Denitrification in aerobic conditions was observed, which showed the presence of DNPAOs and DNGAOs. In batch experiments, PAOs were shown as the most important microorganisms for the phosphorus removal in this experiment, and the role of DNGAOs was higher than that of DNAPOs for the nitrogen removal.

선박에서 발생하는 오·폐수를 처리하기 위하여 생물학적 질소 및 인의 제거공정으로 사용되고 있는 연속 회분식 공정을 이용하여 유기물의 제거 특성과 산소 소모량, 반응조내에서 우점하고 있는 Bacillus sp.균주의 상태를 알아보기 위하여 Lab-sacle로 수행하였다. 반응조에서 COD의 제거효율은 92.0%, 암모니아성질소는 90.0%, 총질소의 제거효율은 84.0%, 인의 제거효율은 93.0%로 나타났다. Bacillus sp.를 이용한 SBR를 사용한 선박폐수의 처리효율은 안정적이었다. 포기시에 SBR 내의 pH는 초기의 8.1에서 30분동안에 pH는 7.0으로 감소하였다. 무산소 단계인 3단계와 4단계에서 pH는 증가하기 시작하여 최종적으로 pH는 7.3으로 유지되었다. TOC제거량에 대한 슬러지 생성량은 약0.36kg·MLSS/kg·TOC으로 나타났으며 낮은 슬러지 발생율과 높은 슬러지 침강성을 나타내었다. 반응조에서 바실러스균의 평균 우점율은 24.2%로 나타났고 각 반응단계에서 안정적인 처리효율을 얻을 수 있어 충분히 우점화 되었다고 판단할 수 있었다.

본 논문에서는 질소와 인을 동시에 처리할 수 있는 생물학적 처리공정의 하나인 연속 회분식 반응기(SER)를 사용하여 선박에서 발생되는 오ㆍ폐수에 대한 처리 성능을 평가하였다. 본 처리공정에서 Bacillus sp.를 이용하여 질소와 인을 동시에 제거할 수 있었다. 유기물(COD)의 변화는 유입수의 COD의 농도가 370mg/l이고 유출수에서 6.5mg/l 제거효율이 90.5%이상으로 나타났다. 총 질소는 97%정도 제거하였고 총인은 93%정도를 처리하였다. 계면활성제(MBAS)는 93%이상 처리되어 미생물 처리에 대한 저해작용은 관찰되지 않았다.

The SBR(Sequencing Batch Reactor) process is ideally suited to treat high loading wastewater due to its high dilution rate. SBR operates by a cycle of periods consisting of filling, reacting, settling, decanting and idling. The react phases such as aeration or non-aeration, organic oxidation, nitrification, denitrification and other biological reactions can be achieved in a reactor. Although the whole reactions can be achieved in a SBR with time distributing, it is hard to manage the SBR as a normal condition without recognizing a present state. The present state can be observed with nutrient sensors such as NH4+-N, NO2--N, NO3--N and PO43--P. However, there is still a disadvantage to use the nutrient sensors because of their high expense and inconvenience to manage. Therefore, it is very useful to use common on-line sensors such as DO, ORP and pH, which are less expensive and more convient. Moreover, the present states and unexpected changes of SBR might be predicted by using of them. This study was conducted to get basic materials for making an inference of SBR process from ORP(oxidation reduction potential) of synthetic wastewater. The profiles of ORP, DO, and pH were under normal nitrification and denitrification were obtained to compare abnormal condition. And also, nitrite and nitrate accumulation were investigated during reaction of SBR. The bending point on ORP profile was not entirely in the low COD/NOx ratio condition. In this case, NOx was not entirely removed, and minimum ORP value was presented over -300mV. Under suitable COD/NOx ratio which complete denitrification was achieved, ORP bending point was observed and minimum ORP value was under -300mV. Under high COD/NOx ratio, ORP bending point was not detected at the first subcycle because of the fast denitrification and minimum ORP value was under -300mV at the time.

Sequencing Batch Reactor(SBR) experiments for organics and nutrients removal have been conducted to find an optimum anaerobic/anoxic/aerobic cycling time and evaluate the applicability of oxidation-reduction potential(ORP) as a process control parameter. In this study, a 6 ℓ bench-scale plant was used and fed with night-soil wastewater in K city which contained TCODcr : 10,680 ㎎/ℓ, TKN : 6,893 ㎎/ℓ, NH_4^+ -N : 1,609 ㎎/ℓ, PO_4^3- -P : 602 ㎎/ℓ on average. The cycling time in SBRs was adjusted at 12 hours and 24 hours, and then certainly included anaerobic, aerobic and anoxic conditions. Also, for each cycling time, we performed 3 series of experiment simultaneously which was set up 10 days, 20 days and 30 days as SRT. From the experimental results, the optimum cycling time for biological nutrient removal with night-soil wastewater was respctively 3hrs, 5hrs, 3hrs(anaerobic-aerobic-anoxic). Nitrogen removal efficiency was 77.9%, 77.9%, 81.7% for each SRT, respectively. When external carbon source was fed in the anoxic phase, ORP-bending point indicating nitrate break point appeared clearly and nitrogen removal efficiency increased as 96.5%, 97.1%, 98.9%. Phosphate removal efficiency was 59.8%, 64.5%, 68.6% for each SRT. Also, we finded the applicability of ORP as a process control parameter in SBRs.