A-B Process는 A 단계에서 에너지 회수능력을 획기적으로 향상시키고, B 단계에서는 에너지 소비를 절감할 수 있는 기술로 구성되는 것을 특징으로 한다. A-B Process는 다양한 단위기술로 구성이 가능하며, 향후 에너지 생산 하수처리 시설을 위해서 필수적이라고 할 수 있다. 대표적으로 A단계는 고속활성슬러지 공법 또는 혐기처리로 구성하여 일반 활성슬러지공법과 대비 높은 COD Capture가 가능하며, A단계에서 제거되지 않은 일부 유기물과 질소는 B단계에서 단축질산화/탈질공정 또는 부분질산화/아나목스 공정으로 에너지를 절감한 형태로 효율적인 제거가 가능하다. 본 연구는 A단계에서 혐기성 세라믹 분리막 생물반응조 공정을 도입하여 하수처리로부터 90% COD Capture가 가능하였다.

In this study, we suggested the jacking method of small diameter sewer pipe for improving workability of the pipe at the weak ground. The jacking method minimizes the space and time in constructing small diameter sewer pipe. In addition, to use this method do not cause road restrictions during the construction period. In this study, the construction process of the small diameter sewer pipe is explained. In addition, to ensure the safety during construction, the design consideration such as earth pressure and the jacking force of the steel pipe, and safety against boiling of the ground were examined. For verify the safety of this jacking method, it is necessary to carry out an experiment to estimate the safety of main pipe under construction.

This study applied microbubbles to reduce membrane fouling in wastewater reuse membrane processes, evaluated and compared the transmembrane pressure with or without the application of microbubbles and the cleaning efficiency with the application of aeration and microbubbles. In addition, this study analyzed foulants removed from the membrane surface. Changes in the transmembrane pressure of membranes with the presence or absence of microbubbles were observed. As a result, transmembrane pressure (TMP) increasing rate decreased twofold when applying microbubbles to realize stable operations. This study compared and evaluated cleaning efficiency applying aeration and microbubbles. As a result, the cleaning efficiency was 5% higher on average when applying microbubbles. In turbidity and total organic carbon (TOC), foulants were discharged when applying microbubbles twice as much as applying aeration. It is thought that particulate foulants precipitated on the membrane surface were more likely to desorb because the adhesion between the membrane surface and particle was weakened by microbubbles. Therefore, it is considered possible to effectively control membrane fouling because of the increase in cleaning efficiency when applying microbubbles to wastewater reuse membrane processes.

Due to the sewer induced ground subsidence, there is an increasing demand for the advanced visual inspection technique for the existing sewer pipe structures. This study aim to develop a visual inspection device and real-time transmission system of inspection data with precisely evaluated structural and operational conditions of underground sewer pipe structures. In this paper, a high-precision image capturing system that automatically extracts cracks in the large-diameter sewer pipes and sewage culverts with a diameter of 1,000 mm or more, a real-time gas detection sensor for investigator safety were studied. By analyzing the module technology of the visual inspection device, the concept design for system integration was derived, and the real time transmission system of the inspection result was developed to establish the technical basis for the commercialized device. Also the crack detection test using crack calibration was carried out for the proposed image capturing camera system, and the position accuracy using L1 grade GPS module was tested in this study. The inspection technique of the existing structure condition using the visual inspection device in this study can be effectively used for various structures types and advanced composite structures in the future.

For economic evaluation of integrated operation to sewage facilities, benefit-cost analysis was performed to watershed sewage works project in 7 watershed areas, 156 facilities. In this study, the cost before and after integrated operation was compared and benefits are calculated from the reduction of operators, increasement treated pollution loads, reduction cost through operation convenience, reduction water consumption through effluent reuse, and improvement of life benefit. The result showed that cost was 8,500million won and benefit was 16,747million won, so benefit was 49% higher than cost. B/C analysis result showed that B/C ratio was 1.97 and it is similar to other researches. The benefits of integrated operation included convenience of data management, increase of emergency response, decrease of complains with sewage which was not reflected numerically, so the benefits of integrated operation were expected much greater than this result.

This study was performed to propose the sewer defect scoring, and grading protocols for sewer condition assessment. For this, sewer defect scoring methods were comparatively analyzed and reviewed for four international condition assessment protocols, which are established based on WRc manual. As a result, we proposed a new protocol for sewer condition assessment, in which characteristics of sewer pipes are considered by segment. In reference to the PIM-3, the extent of ground subsidence was adopted to be of importance, and renewal scores increased in accordance with weighting of defects causing structural backfill materials. Also, defect grades of ‘Hole’ were extended to 5 levels of the grading, and ‘Surface Damage’ was excluded in defect assessment. The addition of ‘Buckling’ resulted in reduction of weights in ‘Surface Damage’ and ‘Lining Defects’.

Modified coagulants were investigated for the removal of phosphorus from secondary effluent of wastewater treatment. The modified coagulants were prepared by mixing alkali earth metal ions such as calcium and magnesium. The basicity of a coagulant influenced on the removal of phosphorus, and coagulants with basicity of 5.9% showed a better removal of total phosphorus than that of 38.5%. Also, coagulants with alkali earth metals enhanced the performance of coagulation by 10% and resulted in 67.1% for total phosphorus removal. Moreover, the removal of suspended solids and chemical oxygen demand was improved using coagulants with low basicity and earth metal ions. Results of this study demonstrated that the use of coagulants with low basicity, and calcium and magnesium ions is recommended to improve wastewater effluent quality.

In this study, we investigated influent and effluent water pollutants in 53 Public Sewage Treatment Works (PSTWs) where industrial wastewater or landfill leachate is combined four times for two years from 2014 to 2015. Also, we analyzed the characteristics of heavy metals and volatile organic carbons at influent and effluent of these PSTWs caused by sewage treatment combined with industrial wastewater or landfill leachate. As a result, six heavy metals such as barium, copper, iron, manganese, nickel and zinc, and four volatile organic carbons (VOCs) including phenols, di(2-)ethylhexyl phthalate (DEHP), formaldehyde and toluene were observed above detection limits in most of PSTWs. Also, it was revealed that six heavy metals such as hexavalent chromium, mercury, cadmium, chromium, nickel and selenium, and four VOCs including 1,1-dichloroethylene, vinyl chloride, naphthalene, and epichlorohydrin were observed more frequently according to precipitation. As a result of reviewing the monitoring data on “Water Quality Monitoring Networks” in lower watersheds of PSTWs, both heavy metals and VOCs were below detection limits, indicating that the effluent water had little influence on the watershed. Nevertheless for the better management of influent and effluent pollutants in PSTWs, it is necessary to establish the advanced management plans for water pollutants in PSTWs, which include a list of priority substances management, monitoring plans, and guidelines for industrial wastewater and landfill leachate combined in PSTWs.

Coagulation/precipitation process has been widely used for the removal of phosphate within domestic wastewater. Although Fe and Al are typical coagulants used for phosphate removal, these have some shortages such as color problem and low sedimentation velocity. In this study, both Fe and Al were used to overcome the shortages caused by using single one, and anionic polymer coagulant was additionally used to enhance sedimentation velocity of the precipitate formed. Batch experiments using a jar test were conducted with real wastewater, which was an effluent of the second sedimentation tank in domestic wastewater treatment plant. Response Surface Methodology was used to examine the responsibility of each parameter on phosphate removal as well as to optimize the dosage of the three coagulants. Economic analysis was also done on the basis of selling prices of the coagulants in the field. Phosphate removal efficiency of Fe(III) was 30% higher than those of Fe(II). Considering chemical price, optimum dosage for achieving residual phosphate concentration below 0.2 mg/L were determined to be 18.14 mg/L of Fe(III), 2.60 mg/L of Al, and 1.64 mg/L of polymer coagulant.

Sewer condition assessment involves the determination of defective points and status of aged sewers by a CCTV inspection according to the standard manual. Therefore, it is important to establish a reliable and effective standard manual for identifying the sewer defect. In this study, analytic reviews of the CCTV inspection manuals of the UK, New Zealand, Canada and South Korea were performed in order to compare the defect codes and the protocols of condition assessment. Through this, we also established the standardized method for defect code and revised the calculation method of assigning the condition grade. Analyses of the types and frequencies of sewer defects that obtained by CCTV inspection of 7000 case results, showed that the joint defect and lateral defect were the most frequent defects that occurred in Korea. Some defect codes are found to be modified because those did not occur at all. This study includes a proposed new sewer defect codes based on sewer characteristics.

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.

This study was begun with the object of actively reflection the rapid technological advancements of the electronical control and mechanical control industries to sewage disposal methods. Or focuses on applying a flow control method that utilizes inverters and automatic valves to sewage treatment process systems.This study proposes that sewage treatment process systems architects must acquire a certain degree of technical skills in the areas of electrical and mechanical controls in order to raise the standard of completeness of sewage treatment process systems. And further emphasizes that there is required continuous research on automatics valves that are used in sewage treatment.

The purpose of this study is to produce the auxiliary fuel additives that will improve the heat value and reduce the odor of dried sewage sludge, an auxiliary fuel for power plants using process by-products. Through an odor analysis prior to the production of auxiliary fuel additives, it was confirmed that the main odor materials are Methylmercaptan, Acetaldehyde and Trimethylamine. Based on this, we measured the heating value on various processes by-products such as by-products of thermal power generation and by-products of refinery. In addition, the adsorption performance in the major odor material was evaluated. However, for Trimethylamine, it is very difficult to secure the reproducibility of the concentration of the standard materials as the standard material is liquid. Therefore, it was used Ammonia, which has basic property, to replace Trimethyamine. In the evaluation of various process by-products, the highest heating value in heavy oil fly ash was 5,575 kcal/kg, while in the adsorption performance evaluation, FCC was shown as having the best performance in adsorption, as it could adsorb 100% of Methylmercaptan, 47% of Acetaldehyde and 76% of Ammonia. We conducted an adsorption experiment after supporting a transition metal on the FCC in order to improve the adsorption capacity. As a result, it was confirmed the best efficiency when supporting the copper nitrate 0.5% on the FCC. Based on this result, the experiment was conducted to determine the optimal mixing ratio with a high heating value and odor reducing function using Heavy oil fly ash and FCC. The optimal mixing ratio was 90% of Heavy oil fly ash and 10% of FCC. Furthermore, it was found that the most economical performance and highest odor reducing efficiency was achieved when the mixing ratio was 90% of dried sewage sludge and 10% of auxiliary fuel additives.

This study was performed to improve the foaming generated in the effluent of wastewater treatment plant from March 2015 to July 2016. The main cause of foaming was air entrainment by an impinging jet and the internal accumulation by the diffusion barrier. Particularly, the foam growth was most active when there is low tide and larger discharge. To solve this problem, we experimented after installing fine mesh screen and the artificial channel device with underwater discharging outlet in the treated wastewater discharge channel and the outlet, respectively. As a result, the effects of foam reduction by devices ranged 85.0~92.0% and 70.7~85.6%, respectively. In addition, the foam and the noise were easily solved, first of all look to contribute to the prevention of complaints. Our device studies were applied to a single wastewater treatment plant. However, it is considered to be able to apply in other similar cases of domestic sewage treatment plants.

Recent frequent occurrence of urban sinkhole brings a need for the periodic inspection of sewer pipelines. Sewer inspection using a CCTV device needs a lot of time and efforts. Many of previous studies which have focused to reduce the laborious tasks are mainly interested in the developments of image processing S/W and inspection H/W. Nevertheless, there has been no attempt to find meaningful information from the existing CCTV images stored by the sewer maintenance manager. In this paper, we carried out a study about the construction of unfolding image of sewer video image. In general, the analysis results show that the image development is judged to have been well represented. It is expected to be a reference to the basic research of panoramic image.

Various kinds of processes are used in the Public Sewage Treatment Works(PSTWs) in order to achieve water quality criteria and TMDL in the watershed. The performance of the existing processes at PSTWs depends on influent characteristics, effluent quality target, amount of sludge production, power cost and other factors. In present, the Selection Guideline for the Available Treatment Process of PSTWs is used for a process decision in the country. But there are some problems regarding redundancy of assessment factors and complexity of assessment procedure in the guideline. In this study, we did a test application of AHP for process selection of PSTWs, which propose is to simplify assessment factors such as pollutant removal amount, sludge generation, electricity consumption, stability of operation, convenience of maintenance, easiness of existing process application, installation cost, and operating cost concerning of environmental factors, technical factors and economical factors. According to the study, the PSTWs selection procedure guideline can be improved using application of AHP method.

Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of CODMn, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

본 연구에서는 하수슬러지 가용화를 위한 불용성전극을 개발하여 전기화학적 특성을 확인 하였다. 이리듐을 주촉매로 사용하여 하수슬러지 가용화에 적합한 촉매를 선정하여 내구성이 우수하고 하수슬러지 전기분해에 적합한 기능성 전극 실험을 진행하였고 다음과 같은 결과를 얻었다. 전극의 코팅 소성온도를 주 촉매인 Ir의 질량감소가 적고, 흡열반응 구간인 300℃부터 500℃까지의 범위로 선정하고 실험을 하였다. 실험결과 350℃에서 촉매의 효율성이 가장 우수하게 나왔다. 각각의 바인더 별(Ta, Sn, W) 실험에서도 350℃에서 가장 큰 촉매효율성이 나타났다. 바인더로 사용한 탄탈럼, 주석, 텅스텐 중 탄탈럼이 다른 금속보다 주 촉매의 특성을 그대로 유지시키며 전극의 효율성을 향상시키는 것을 확인하 였다. 50%IrO2 전극의 경우 1.4 V(vs. Ag/AgCl) 약 29 mA/cm2 의 전류가 발생하여 전극의 효율을 평 가하였다.

Various studies have forwarded an outstanding wastewater effluent treatment systems toward securing sustainable supply of water sources. In this paper, a broad overview of the performance of MF membrane as pretreatment option for wastewater reuse will be presented based on the literature survey and experiments conducted over the wastewater reuse pilot plant. The pilot plant was operated with a continuous data acquisition for about 300days under various chemical enhanced backwash (CEB) system with subsequent treated water quality analysis. Accordingly, assessment of the effluent revealed that the pretreated water is suitable enough to be used as an input for Reverse Osmosis (RO) unit and significant effect of CEB and concentration of NaOCl is also conceived from the analysis. Moreover, it's also observed that the application of various CEB condition over long operational hours induced a constant declination of overall performance of MF membrane.

There has been an accelerating increase in water reuse due to growing world population, rapid urbanization, and increasing scarcity of water resources. However, it is well recognized that water reuse practice is associated with many human health and ecological risks due to numerous chemicals and pathogenic microorganisms. Especially, the potential transmission of infectious disease by hundreds of pathogenic viruses in wastewater is one of the most serious human health risks associated with water reuse. In this study, we determined the response of different bacteriophages representing various bacteriophage groups to chlorination in real wastewater in order to identify a more reliable bacteriophage indicator system for chlorination in wastewater. Different bacteriophages were spiked into secondary effluents from wastewater plants from three different geographic areas, and then subjected to various doses of free chlorine and contact time at 5˚C in a bench-scale batch disinfection system. The inactivation of φX174 was relatively rapid and reached ∼4 log10 with a CT value of 5 mg/L*min. On the other hand, the inactivation of bacteriophage PRD1 and MS2 were much slower than the one for φX174 and only ~1 log10 inactivation was achieved by a CT value of 10 mg/L*min. Overall, the results of this study suggest that bacteriophage both MS2 and PRD1 could be a reliable indicator for human pathogenic viruses for chlorination in wastewater treatment processes and water reuse practice.