본 연구에서는 하수처리 과정에서 분리된 항생제 내성균(Antibiotic Resistant Bacteria, ARB)을 제거하기 위해 박테리오파지와 차아염소산 나트륨(NaClO)을 결합한 병용 처리 기술을 응용하였다. ARB를 감염시키는 용균성 박테리오파지는 폐수 샘플에서 성공적으로 분리되었다. 이러한 박테리오파지와 NaClO를 순차적으로 적용한 결과, 5시간 이내에 ARB를 상당히 감소시킬 수 있었다. 환경 안정성 평가에서는 분리된 박테리오파지가 온도, pH, 독성 물질에 대한 노출 등 다양한 조건에서도 효과를 유지하는 것으로 나타냈다. 또한, 실험실 규모의 반응기 실험을 통해 단독 염소 소독과 비교했을 때, 결합 처리가 ARB를 효과적으로 억제하는 것을 확인할 수 있었다. 박테리오파지와 차아염소산 병용 처리는 유기물, 질소(N), 인(P)과 같은 영양소 제거 효율에 영향을 미치지 않았다. 이러한 결과는 박테리오파지를 기반으로 한 생물학적 제어법과 기존의 소독 방식을 결합하여 폐수 처리 공정(Wastewater treatment plant, WWTP)에서 효과적인 항생제 내성 박테리아 제어 방안을 제시할 가능성을 시사한다.

Due to the onset of urbanization worldwide, there is an increasing demand for improving the quality of the urban environment. Odor in wastewater collection systems (WCSs) can interfere with the comfortable and safe living conditions of citizens. Additionally, it can cause economic losses, such as the corrosion of wastewater collection facilities. In this paper, the mechanism of odor generation in WCSs was summarized, and the odor concentrations and sulfide generation rates measured in domestic and foreign WCSs were comprehensively analyzed to review the characteristics of odor emission in WCSs. The complex odor intensity (dilution-tothreshold value) measured in combined domestic sewers ranged from 10 to 10,000, with a median of 100. The odorous compound with the highest contribution to complex odor intensity was hydrogen sulfide, which was the odor most frequently detected at the highest concentrations in most WCSs (its median and mean concentrations were 378.0 ppb and 3,771.2 ppb, respectively). The odor emission properties in the WCSs in Australia and Finland were similar to those of South Korea, with the median and mean concentrations of hydrogen sulfide being 1,927.5 ppb and 12,306.1 ppb, respectively. The sulfide generation rates measured in domestic and foreign WCSs ranged from 0.003 to 0.220 g m–2 h–1. In addition, the key factors affecting sulfide generation were sulfate and organic matter concentrations, pH, temperature, flow rate (retention time), dissolved oxygen concentration, and electron acceptor concentrations other than sulfate. To control odor in WCSs, various methods have been proposed to improve their anaerobic environment. These include sucking outside air into the WCSs and improving their hydraulic conditions, such as changing the slope of sewer pipes to minimize sediment deposition. Additionally, periodically removing sediments, which contain a significant amount of organic matters and sulfate-reducing bacteria, is also a useful method for controlling odor in WCSs. Since the odor compounds that contribute the highest odor intensity–and are the most frequently detected–are sulfur-containing odors such as hydrogen sulfide, the control of sulfides is crucial for controlling odor in WCSs. There are chemical control methods for the mitigation of sulfide in WCSs, including air (oxygen) injection and introducing various chemicals, such as alkalis, nitrates, iron salts, and biocides. However, most of the results of odor control using these methods were from laboratory-scale studies. Therefore, additional field-scale experiments should be conducted in WCSs to evaluate the actual effectiveness of various odor control methods. Through these field studies, the optimal conditions for each method to control odor in WCSs can be derived, and the efficiency and economic feasibility of each method can be verified.

A total of 10,977 individual sewage treatment facilities(ISTFs) have been installed and operated on Jeju island as of 2022. The number of ISTFs has increased rapidly in the hillside area, where the elevation is above 200 m and is recognized as a major area for groundwater recharge. A total of 80 ISTFs were selected for this study, with a particular focus on their management status and effluent water quality. This was carried out in two areas, Aewol-eup and Jocheon-eup, which are known to have the highest density of ISTFs in Jeju island. Consequently, 23.9% of ISTFs failed to remove sludge regularly, and 41.3% of ISTFs did not run the blower. The effluent water quality revealed that violating percentage of the legal standards for BOD, SS, T-N, and T-P were 75.0%, 62.5%, 100%, and 86%, respectively. To assess the efficiency of effluent quality by management, an independent t-test and ANOVA were conducted. The BOD and TOC differed significantly according to the building usage. Therefore, it can be concluded that the effluent from ISTFs should be managed according to the building usage. Furthermore, no distinction was observed in contamination components due to blower operation, with the exception of DO. However, the mean value of the NH4 +-N/T-N ratio was found to decrease with DO, indicating that blower operation may potentially reduce the contamination burden of ammonium in groundwater.

2021년 기준 4,339개소의 공공하수처리시설에서 발생하는 하수찌꺼기는 년간 4,271,110톤으로 하수처리장 신·증설 등으로 인해 매년 증가하고 있다. 하수찌꺼기 등 유기성폐자원의 처리를 위해서 퇴비화, 혐기성 소화, 열분해, 소각, 매립 등 다양한 방법이 적용되고 있다. 특히 혐기성 소화는 잔류고형물 저감, 자본비와 운영비 절감, 바이오에너지 생산 및 환경에 대한 영향 최소화 등의 장점을 지니고 있어 실행 가능한 방법 중의 하나로 간주되고 있다. 그러나 하수찌꺼기 등과 같이 고형물을 함유한 유기성폐자원의 혐기성 소화 시 가수분해 반응은 율속단계로 알려져 있다. 따라서 혐기성 소화 시 가수분해 효율을 증진하기 위하여 초음파, 마이크로웨이브, 화학적 전처리, 열가수분해 등의 방법이 적용되고 있다. 특히 열가수분해의 경우 지난 20년간 관련 연구가 꾸준히 이루어져 많은 수의 실 규모 시설이 현장에 적용되었다. 그럼에도 불구하고 높은 에너지 소비, 혐기성 소화 저해물질 생성 및 색도로 인한 자외선 소독 효율 저감 등으로 인해 아직도 관련 연구가 지속적으로 진행 중이다 따라서 본 논문에서는 하수찌꺼기의 안정화와 혐기성 소화조의 효율 향상을 위해 가용화 기술 중 대표적이고 상용화가 가장 많이 이루어진 열가수분해에 대해 고찰하고자 한다. 특히 하수처리시설에서 열가수분해와 혐기성 소화조를 연계 하는 경우 예상되는 문제점과 해결방안에 대한 제시를 통해 혐기성 소화조의 안정성 및 메탄 발생량 향상, 하수처리시설 찌꺼기의 효율적 저감 및 에너지 자립화에 기여하고자 한다.

A study on the denitrification of reverse osmosis(RO) concentrated wastewater from sewage reuse treatment plant in P city was conducted using waste desulfurization agent obtained from desulfurization process. Sulfur-based autotrophic denitrifying carrier comprises the predetermined amount of waste iron sulfide (FeS, Fe2S3), mine drainage sludge and elemental sulfur showing mesoporisity with 9.9 nm (99 Å) of average pore size. Sulfur denitrifying bacteria and sulfur reducing bacteria were implanted into the pores of sulfur denitrifying carrier. Nitrate was not affected by empty bed contact time (EBCT). It is probably due to larger reducing capacity of the carrier than the concentration of nitrate in RO concentrated wastewater. Total nitrogen (T-N) removal efficiency exhibited about 90% after 4 days. Sulfate ion was surprisingly decreased with sulfur autotropic process due to the reduction of sulfate ion to HS- and S2- by sulfur reducing bacteria. Sulfide and hydrogen sulfide ions were then taken by Fe(OH)3, main component of mine drainage sludge, releasing OH-. Alkalinity was therefore maintained between 7.5 and 8.5 in pH by the released OH-. Also, it had the effect of suppressing the production of H2S, which causes bad odor.

To mitigate carbon emissions, the government aims to transition to renewable energy sources including hydrothermal energy, specifically through wastewater heat recovery. This process involves extracting heat from wastewater or treated water. However, assessments of demand sources for local cooling and heating have predominantly focused on the proximity of nearby facilities, without conducting comprehensive demand analyses or defining explicit supply areas. This study proposes a methodology for prioritizing suitable wastewater treatment plants (WWTPs) for the implementation and expansion of renewable energy. The methodology is based on the gross floor area of potential wastewater heat demand surrounding WWTPs. Initially, potential supply and demand sources were identified based on the capacity of WWTPs and the gross floor area of buildings capable of utilizing wastewater heat. In the Republic of Korea, 330 WWTPs with a capacity of 5,000 m3/day or more have been recognized as demand sources for wastewater heat recovery. The provision of treated wastewater to structures located within a 500 m radius of the WWTPs for heat recovery is considered a feasible option. The potential wastewater heat demand and renewable energy cluster were identified among the surrounding buildings and complexes A total of 13 potential supplies were identified, provided that the gross floor exceeded 60,000 m². Finally, after prioritizing based on WWTPs with these conditions, the underground plant located in the downtown area was ranked as the highest priority. If further analysis of economic feasibility, CO2 reduction, and energy efficiency are conducted, this approach can be expanded and applied within the framework the Water-Energy Nexus. Wastewater heat can be utilized not only as a renewable energy source but also as a means to enhance wastewater reuse through the supply of treated wastewater.

This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

This study explored effects of a sludge-based biochar addition on nitrogen removal of membrane bioreactor (MBR) for wastewater treatment. The membrane fouling reduction by the biochar addition was also investigated. A dose of 3 g/L of the biochar was applied to an MBR (i.e., BC-MBR) and treatment efficiencies of organic matter and nutrient were analyzed. The MBRs with powdered activated carbon (i.e., AC-MBR) and without any additives were also operated in parallel. The average removals of COD and TN were improved with the biochar addition compared to those with the control MBR. Interestingly, operational duration was also increased with biochar addition. The CLSM analysis revealed that biomass amounts of BC-MBR and AC-MBR were reduced by more than 40%, and thickness of the biofilm attached to the membrane surface also was decreased. The physical properties of biochar surfaces were compared with a commercial powdered activated carbon. The specific surface area with 38 m2/g and pore volume with 0.13 cm3/g of the biochar were much smaller than those of the powdered activated carbon, which were 1100 m2/g and 0.67 cm3/g, respectively. Manufacturing conditions for the biochar production needs to be further investigated for enhancing physical properties for adsorption and biological improvement.

하수기반역학을 이용한 코로나19 감시 결과, 연구기간 (2022년 8월-2023년 8월)동안 울산지역 4곳 하수처리장의 전체 174건 모든 시료에서 코로나바이러스-19가 검출되었 다. 확진자 수와 하수 내 코로나바이러스 농도와의 상관 분석 결과, 높은 상관성이 나타났으며 특히 하수감시가 임 상감시보다 2-3주 앞서 농도가 증가함으로써 조기 인지의 가능성도 볼 수 있었다. 또한 코로나19 변이 분석 결과 역 시 유행 시기별 우세종화된 변이와 비교적 유사하여 변이 예측도 가능하였다. 하수감시가 전국적, 전세계적으로 적용되고 있으며 많은 연구가 국가적 사업으로 진행되고 있 다. 이에 따라, 하수 분석방법 및 분석기기 발전 등의 지 속적 연구 업데이트가 필요하다. 또한 코로나19를 통해 감 염병의 선제적 모니터링 및 유행 예측의 가능성을 확인하 였으므로 다양한 병원체 및 식품·의약품 등에 확대 적용 이 진행 중이다. 따라서 본 연구는 감염병 검출분야에서 더 나아가 하수 내 식품 성분, 활성물질 및 미생물 등의 분석을 통해 지역사회의 식품안전 및 전반적인 위생환경 감시를 위해 활용될 수 있을 것으로 기대된다.

The purpose of this study is to analyze the correlation between ecotoxicity and water quality items using Daphnia magna in public sewage treatment plant process and to obtain operational data to control ecotoxicity through research on removal efficiency. The average value of ecotoxicity was 1.39 TU in the influent, 1.50 TU in the grit chamber, and 0.84 TU in the primary settling tank and it was found that most organic matters, nitrogen, and phosphorus were removed through biological treatment in the bioreactor. Using Pearson’s correlation analysis, the positive correlation was confirmed in the order of ecotoxicity and water quality items TOC, BOD, T-N, NH3-N, SS, EC, and Cu. As a result of conducting a multilinear regression analysis with items representing positive correlation as independent variables, the regression model was found to be statistically significant, and the explanatory power of the regression model was about 81.6%. TOC was found to have a significant effect on ecotoxicity with B=0.009 (p<.001) and Cu with B=16.670 (p<.001), and since the B sign is positive (+), an increase of 1 in TOC increases the value of ecotoxicity by 0.009 and an increase in Cu by 1 increases the value of ecotoxicity by 16.670. TOC (β=0.789, p<.001) and Cu (β=0.209, p<.001) were found to have a significant positive effect on ecotoxicity. TOC and Cu have a great effect on ecotoxicity in the sewage treatment plant process, and it is judged that TOC and Cu should be considered preferentially and controlled in order to efficiently control ecotoxicity.

In the context of the Ministry of Environment’s 2022 Climate Change Adaptation Plan for Public Institutions, public sewage treatment plants are one of the important targets for climate change response aimed at sustainable water management. In this study, it is applied a modified methodology to four water regeneration centers (public sewage treatment facilities) in charge of sewage treatment in Seoul to analyze the impacts and risks of climate change and discuss priorities for adaptation measures. The results of the study showed that heavy rains, heat waves, and droughts will be the key impacts of climate change, and highlighted the need for measures to mitigate these risks, especially for facility managers.

Small hydropower systems have emerged as an attractive solution for areas with low head and flow rates, offering versatility for implementation in diverse locations such as rivers and wastewater treatment plants. This research specifically focuses on exploring the potential of small hydropower generation within wastewater treatment plants. Through the utilization of computational fluid dynamics (CFD) analysis, the study successfully predicted the torque and power generation capacity of the installed turbine. The analysis underscored the effective control of fluid flow achieved through careful turbine design, including considerations of blade shape and quantity. For instance, in the case of the Tancheon wastewater treatment plant, the study revealed the ability to generate a torque of approximately 7000 Nm, translating to an estimated power production of around 48.3 kW per hour. Ultimately, this research significantly contributes to evaluating the feasibility and viability of small hydropower generation within wastewater treatment plants.

The object of this study is to feasibility assesment for co-digestion efficiency of food waste recycling wastewater(FWR) with thermal hydrolysis process dehydration cake (THP Sludge). As a result of THP pre-treatment experimental conditions to 160oC and 30 minutes, the solubility rate(conversion rate of TCOD to SCOD) of the THP sludge increased by 34%. And the bio-methane potential in the THP sludge increased by about 1.42 times from 0.230 to 0.328 m3 CH4/kg VS compared to the non-pre-treatment. The substrates of the co-digestion reactor were FWR and THP sludge at a 1:1 ratio. Whereas, only FWR was used as a substrate in the digestion reactor as a control group. The experimental conditions are 28.5 days of hydraulic retention time(HRT) and 3.5 kg VS/m3-day of organic loading rate(OLR). During the 120 days operation period, the co-digestion reactor was able to operate stably in terms of water quality and methane production, but the FWR digestion reactor deteriorated after 90 days, and methane production decreased to 0.233 m3 CH4/kg VS, which is 67% of normal condition. After 120 days of the experiment, organic loading rate(OLR) of co-digestion reactor was gradually increased to 4.5 kg VS/m3-day and operated for 80 days. Methane production during 80 days was evaluated to be good at the level of 0.349 m3 CH4/kg VS. As a result of evaluating the dehydration efficiency of the sludge before/after 150-180oC THP using a filter press, it was confirmed that the moisture content of the sludge treated before THP at 180oC was 75% and improved by 8% from 83-85% level. Therefore, it is expected that the co-digestion reactor of FWR and THP sludge will ensure stable treatment water quality and increase bio-methane production and reduction effect of dehydration sludge volume.

본 연구에서는 하수 재이용을 위한 역삼투막 공정에서 전처리 정밀여과막(MF) 손상에 대한 누출되는 다양한 수 질변화로써 막 손상 검지 방안을 제시하였다. 이를 위하여 역삼투막 유입수질 적합성 평가지표인 SDI (silt density index)를 3에서 5의 범위 내에서 막 손상 시 검지 감도를 정량화하기 위하여 전처리 분리막이 1에서 3가닥 파단에 따라 SDI는 1.92에 서 6.11까지 증가한 결과를 확인할 수 있었다. 일반적으로 3을 기준으로 역삼투막 유입수질로 설정하였을 때 분리막이 3가닥 까지 파단이 되어야만 막 손상 검지가 가능하다는 것을 의미하며 역삼투막의 오염은 잠재적으로 가속화되어 효율을 저하시 킬 수 있다. 또한 이때 누출되는 입자성과 유기물질에 대하여 0.45 μm 이상의 크기만 걸러주는 입자계수는 입도분포별 막 파 단 개수에 따라 일정한 패턴을 확인할 수 없었으며, TOC 농도는 약 2배의 변화패턴으로써 SDI와의 상관관계로써 TOC가 막 손상 수질지표로써 신뢰성이 높은 것으로 확인되었다. 수질분석결과와 더불어 USEPA에서 제시하는 막 손상 검지 방법 중 압력손실시험과 이를 기반으로 LRVDIT 모델의 적합성 평가를 한 결과 막 손상 또는 역삼투막 공정으로 유입되는 막오염물질 을 신속하게 확인할 수 있는 SDI 및 TOC를 포함한 LRVDIT 모니터링과 UCL 설정을 병행해야 한다.

The sewer capacity design have been based on the Huff model or the rational equation in South Korea and often failed to determine optimal capacity, resulting in frequent urban flooding or over-sizing. A time distribution of rainfall (i.e., Huff or ABM method) could be used instead of a rainfall hyetograph obtained from statistical analysis of previous rainfalls. In this study, the Huff method and the ABM method, which predict the time distribution of rain intensity, which are widely used to calculate sewage pipe drainage capacity using the SWMM, were compared with the standard rainfall intensity hyetograph of Seoul. If the rainfall duration was 30 minutes to 180 minutes, the rainfall intensity value calculated by the Huff model tended to be less than the rainfall intensity value of the standard rainfall intensity in the initial 5-10 minutes. As a result, more than 10% to 30% of under-design would be made. In addition, the rainfall intensity value calculated by the Huff model from the section excluding the initial 5-10 minutes of rainfall to the rainfall duration was calculated larger than the value using the standard rainfall intensity equation, which would result in an over-design of 10% to 30%. In the case of a relatively long rainfall duration of 360 minutes (6 hours) to 1,440 minutes (24 hours), it showed an lower rainfall intensity of 60 to 90% in the early stages of rainfall, but the problem of under-design had been solved as the rainfall duration time had elapsed. On the other hand, in the alternating block method (ABM) method, it was found that the rainfall intensity at the entire period at each assumed rainfall duration accurately matched the standard rainfall intensity hyetograph of Seoul.

자기공명영상(MRI) 장비의 조영제로 흔히 사용되는 가돌리늄(Gd)은 매우 안정된 상태로 하수처리과정에서 거의 제거되지 않고 수환경으로 유입된다고 알려져 있다. 따라서 본 연구에서는 세 가지의 공법으로 하수처리를 하는 부산 수영 하수처리장에서 채취한 하수 시료의 공정별 용존 희토류 원소의 제거율 및 수환경으로 배출되는 인위적 기원 Gd (Gdanth)의 배출량을 평가하고자 하였다. 용존 희토류 원소는 공정별 처리 단계에 따라 무거운 희토류 원소(Tb-Lu)에 비 해 가벼운 희토류 원소(La-Eu)에서 농도가 감소하는 경향을 보였다. 또한 일부 시료에서 나타난 음의(negative) Sm anomaly (<1)는 생물학적 제거 과정에서 Sm이 입자나 인산염과 흡착되어 함께 제거되었을 가능성을 시사한다. 모든 시 료에서 양의(positive) Gd anomaly (149±50, n=9)를 보였으며, 공정별로 측정된 Gd의 총 농도 중 Gdanth은 약 97% 이 상을 차지하는 것으로 나타났다. 이는 하수처리과정에서 Gdanth 이 거의 제거되지 않고 수영강 하류로 배출된다는 것을 의미한다. 일별 처리용량을 고려하여 각 공정에서 배출되는 Gdanth의 배출량은 259 mmol/day로 추정할 수 있다. 본 연 구의 결과는 하수처리장을 통해 수영만 연안으로 Gdanth이 지속적으로 배출될 것으로 예상되며, 향후 Gd의 중장기적인 관측이 필요함을 시사한다.

The frequent detection and occurrence of micropollutants (MPs) in aquatic ecosystems has raised public health concerns worldwide. In this study, the behavior of 50 MPs was investigated in three different domestic wastewater treatment plants (WWTPs). Furthermore, the Kruskal-Wallis test was used to assess the geographical and seasonal variation of MPs in the WWTPs. The results showed that the concentrations of 43 MPs ranged from less than 0.1 to 237.6 μg L-1, while other seven MPs including 17-ethynylestradiol, 17-estradiol, sulfathiazole, sulfamethazine, clofibric acid, simvastatin, and lovastatin were not detected in all WWTPs. Among the detected MPs, the pharmaceuticals such as metformin, acetaminophen, naproxen, and caffeine were prominent with maximum concentrations of 133.4, 237.6, 71.5, and 107.7 μg L-1, respectively. Most perfluorinated compounds and nitrosamines were found at trace levels of 1.2 to 55.3 ng L-1, while the concentration of corrosion inhibitors, preservatives (parabens), and endocrine disruptors ranged from less than 0.1 to 4310.8 ng L-1. Regardless of the type of biological treatment process such as MLE, A2O, and MBR, the majority of pharmaceuticals (except lincomycin, diclofenac, iopromide, and carbamazepine), parabens (except Methyl paraben), and endocrine disruptors were removed by more than 80%. However, the removal efficiencies of certain MPs such as atrazine, DEET, perfluorinated compounds (except PFHxA), nitrosamines, and corrosion inhibitors were relatively low or their concentration even increased after treatment. The results of statistical analysis reveal that there is no significant geographical difference in the removal efficacy of MPs, but there are temporal seasonal variations in all WWTPs.

Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, including their current status of research and development. Advanced oxidation processes (AOPs) such as ozonation and UV/H2O2 and adsorption processes using powdered (PAC) and granular activated carbon (GAC) were mainly discussed with focusing on process principles for the micropollutant removal, effect of process operation and water matrix factors, and technical and economic feasibility. Pilot- and full-scale studies have shown that ozonation, PAC, and GAC can achieve significant elimination of various micropollutants at economically feasible costs(0.16-0.29 €/m3). Considering the current status of domestic WWTPs, ozonation and PAC were found to be the most feasible options for the enhanced sewage effluent treatment. Although ozonation and PAC are all mature technologies, a range of technical aspects should be considered for their successful application, such as energy consumption, CO2 emission, byproduct or waste generation, and ease of system construction/operation/maintenance. More feasibility studies considering domestic wastewater characteristics and WWTP conditions are required to apply ozonation or PAC/GAC adsorption process to enhance sewage effluent treatment in Korea.