Water utilities are making various efforts to reduce water losses from water networks, and an essential part of them is to recognize the moment when a pipe burst occurs during operation quickly. Several physics-based methods and data-driven analysis are applied using real-time flow and pressure data measured through a SCADA system or smart meters, and methodologies based on machining learning are currently widely studied. Water utilities should apply various approaches together to increase pipe burst detection. The most intuitive and explainable water balance method and its procedure were presented in this study, and the applicability and detection performance were evaluated by applying this approach to water supply pipelines. Based on these results, water utilities can establish a mass balance-based pipe burst detection system, give a guideline for installing new flow meters, and set the detection parameters with expected performance. The performance of the water balance analysis method is affected by the water network operation conditions, the characteristics of the installed flow meter, and event data, so there is a limit to the general use of the results in all sites. Therefore, water utilities should accumulate experience by applying the water balance method in more fields.

For the sake of future generations, the management of radioactive waste is essential. The disposal of spent nuclear fuel (SNF) is considered an urgent challenge to ensure human safety by storing it until its radioactivity drops to a negligible level. Evaluating the safety of disposal facilities is crucial to guarantee their durability for more than 100,000 years, a period sufficient for SNF radioactivity to become ignored. Past studies have proposed various parameters for forecasting the safety of SNF disposal. Among these, radiochemistry and electrochemistry play pivotal roles in predicting the corrosion-related chemical reactions occurring within the SNF and the structural materials of disposal facilities. Our study considers an extreme scenario where the SNF canister becomes compromised, allowing underground water to infiltrate and contact the SNF. We aim to improve the corrosion mechanism and mass-balance equation compared with what Shoesmith et al. proved under the same circumstances. To enhance the comprehensibility of the chemical reactions occurring within the breached SNF canister, we have organized these reactions into eight categories: mass diffusion, alpha radiolysis, adsorption, hydrate formation, solidification, decomposition, ionization, and oxidation. After categorization, we define how each species interacts with others and calculate the rate of change in species’ concentrations resulting from these reactions. By summing up the concentration change rates of each species due to these reactions, we redefine the mass-balance equations for each species. These newly categorized equations, which have not been explained in detail previously, offer a detailed description of corrosion reactions. This comprehensive understanding allows us to evaluate the safety implications of a compromised SNF canister and the associated disposal facilities by numerically solving the mass-balance equations.

In this study, the fate and removal of 15 pharmaceuticals (including stimulants, non-steroidal anti-inflammatory drugs, antibiotics, etc.) in unit processes of a sewage treatment plant (STP) were investigated. Mass loads of pharmaceuticals were 2,598 g/d in the influent, 2,745 g/d in the primary effluent, 143 g/d in the secondary effluent, and 134 g/d in the effluent. The mass loads were reduced by 95% in the biological treatment process, but total phosphorous treatment did not show a significant effect on the removal of most pharmaceuticals. Also, mass balance analysis was performed to evaluate removal characteristics of pharmaceuticals in the biological treatment process. Acetaminophen, caffeine, acetylsalicylic acid, cefradine, and naproxen were efficiently removed in the biological treatment process mainly due to biodegradation. Removal efficiencies of gemfibrozil, ofloxacin, and ciprofloxacin were not high, but their removal was related to sorption onto sludge. This study provides useful information on understanding removal characteristics of pharmaceuticals in unit processes in the STP.

본 연구에서는 갈대군락의 영양염 물질수지 모델 구축을 위한 기초연구로서, 갈대군락 Mesocosm 실험을 통해 수층-갈대(뿌리, 잎, 줄기)-토양의 영양염(DIN, DIP) 농도의 춘계 및 하계 모니터링 결과를 이용하여 물질수지를 산정하였으며, 결과는 다음과 같다. 1) 갈대의 생체량은 춘계에는 지하경이 지상경에 비해 약 6.3~9.7% 높으며, 하계에는 지상경이 지하경에 비해 약 19.2~21.2% 높게 나타났으며, 갈대의 성장속도는 Mesocosm Tank A가 Mesocosm Tank D에 비해 지상경과 지하경 모두 2~3배 정도 빠르게 나타났다. 2) Mesocosm Tank에서의 갈대의 영양염(DIN, DIP) 농도는 춘계와 하계 모두 각각 2~3%로 차이가 적었다. 3) Mesocosm Tank별 생체량의 차이는 최대 23%로 나타나지만, 갈대가 흡수하는 영양염의 농도는 최대 3% 정도로 차이가 적었다.

최근 전북 지역은 바지락 생산량이 감소하여 2015년에 전국 생산량의 17.8%를 차지한 반면, 충남 지역은 점차 증가하여 49.1% 를 차지하였다. 갯벌은 다양한 저서생물이 서식하고 있고, 조석에 의해 물질이 유출·입되는 특성이 있기 때문에 만의 특성을 고려한 물질 수지를 이해하는 것이 중요하다. 본 연구에서는 2015년 5월과 8월에 곰소만과 근소만의 바지락 어장 지역과 외해지역의 차이를 비교하기 위해 3개의 해역(Sector , Sector , Control)으로 구분하고, LOICZ Model을 이용하여 물질수지를 산정하였다. 분석결과 바지락 성장이 활 발한 5월에 바지락 양식장이 밀집한 곰소만과 근소만 Sector 의 DIP는 각각 207.2 kg/day와 77.2 kg/day로 나타났고, DIN은 4,996.7 kg/day와 926.6 kg/day로 나타났다. 주로 양식생물의 섭식작용에 큰 원인으로 보이며, 근소만보다 곰소만에서 바지락 밀식이 이루어지는 것 으로 판단된다. 따라서 건강한 갯벌 생태계 유지와 지속적인 바지락 생산을 위해서는 밀식을 저감하기 위한 지속적인 관리가 필요하다.

The objective of this study was to investigate the response characteristics and performance of a biofilter in the removal of ammonia, as a malodor compound. A trickle-bed type biofilter was applied for this study, and operated at the ammonia loading rate of 0.97-15.52 g/m3·h. The results of the experiment indicate that the critical loading rate of ammonia to the biofilter was 10.7 g/m3·h and the elimination capacity was 11.6 g/m3·h. The analysis of nitrogen mass balance in the reactor indicates that inlet nitrogen as gas phase was converted through the biofilter into NH4 + (41.5% by mass), NO2 - (43%), and NO3 - (15%) as the available form of nitrogen in the effluent liquid. Free ammonia concentration in the effluent liquid was estimated as being in the range from 0.14 to 2.93 mg/L (average 1.7 mg/L) during the experimental period.

Developing two process models to simulate wastewater treatment process is needed to draw a comparison between measured BOD data and estimated process model data: a mathematical model based on the process mass-balance and an ANN (artificial neural network) model. Those two types of simulator can fit well in terms of effluent BOD data, which models are formulated based on the distinctive five parameters: influent flow rate, effluent flow rate, influent BOD concentration, biomass concentration, and returned sludge percentage. The structuralized mass-balance model and ANN modeI with seasonal periods can estimate data set more precisely, and changing optimization algorithm for the penalty could be a useful option to tune up the process behavior estimations. An complex model such as ANN model coupled with mass-balance equation will be required to simulate process dynamics more accurately.

This study was performed to estimate the emission rate of volatile organic compounds (VOCs) and to evaluate the risk level affected by indoor air pollutants (IAPs) in 27 new apartments (prior to residence) in Seoul City from December 2004 to March 2005. The indoor air pollutants investigated in this study include formaldehyde, several aromatic VOCs (benzene, toluene, styrene, xylene, and ethylbenzene). All measurements were made based on the standard method of Ministry of Environment in Korea. The indoor concentration levels for benzene, xylene, toluene, ethylbenzene, styrene, and formaldehyde have significant increase trend 5 hours after closing windows and doors. Levels of air pollutants did not exhibit significant difference between living rooms and bedrooms. The air exchange rates by the concentration decay method using SF6 were 0.37 for low floor, 0.32 for middle floor, and 0.75 for high floor. The emission rate showed the highest level in the middle floor and second one in the low floor, when estimated by the IAQ model for benzene, toluene, ethylbenzene, xylene, styrene, and formaldehyde. Considering the above result, it is suggested that the estimation of emission rate be considered when the new apartment is designed and constructed with respect to construction materials to emit low VOCs. Moreover, the related regulation should be established for IAQ management.

A numerical simulation was conducted on perfluorooctane sulfonate (PFOS) in the Gwangyang Bay using a multi-box model to estimate the transport of organic chemicals in the coastal environment. The results of the sensitivity analysis on dissolved PFOS and PFOS in Particulate Organic Carbon (POC) indicate that they were most significantly influenced by the adsorption rate, desorption rate, and sinking velocity coefficients. PFOS in phytoplankton was found to be sensitive to bio-concentration and the excretion rate. The results of the mass balance indicate that the standing stocks of PFOS in water, POC, and phytoplankton are 345.55 g, 63.76 g, and 0.11 g, respectively, in the inner part and 149.90 g, 27.51 g, and 0.05 g, respectively, in the outer part. Considering flux in the inner part, adsorption to POC had the highest value among transition paths. The next highest were desorption, outflow to the outer part, and inflow to the inner part. Outflow into the open sea was found to have the highest value for the outer part.

Nitrogen budgets in Sihwa-ho in 2010 were estimated using a mass balance approach. Major nitrogen fluxes sources can be divided into three sections: cities, agricultural area, and forest. Surplus nitrogen 2,030~2,214 ton/yr (2,123 ton/yr in average) was discharged to Sihwa Lake. 20% of the surplus nitrogen is removed from the wetland and 60% is removed tidal flats. Therefore net nitrogen discharge from Sihwa basin is estimated to be 650 708 ton/yr (679 ton/yr in average). Wet and dry nitrogen deposition and load from non-point sources ware estimated to be 97 ton/yr and 69 ton/yr, deposition is using CAMx model. So estimated total nitrogen discharge into Sihwa-ho was 817 875 ton/yr (846 ton/yr in average). The atmospheric load explains 11.1 11.9% (11.5% in average) of the total nitrogen load Sihwa-ho.

비성형 SRF 제조공정은 대상지역의 특성과 계절 등 변동요인에 따라 제품품질의 큰 영향을 끼친다. 본 연구에서는 2016년 9월, Y시에 설치되어 있는 15톤/일급 Pilot 비성형 SRF 제조공정에 대하여 총량, 폐기물조성, 수분량 별로 물질수지를 세우고 그 결과를 분석하여 실증시설 설계반영에 반영하고자 하였다. 연속 정상운전 상태에서 각 공정별 시료채취는 3회씩 겉보기밀도, 물리적조성, 조성별 수분 분석을 하였고, 총괄수분 분석을 위한 시료채취는 공정별 각 5회씩 수행하였다. 1차 자력선별물, 2차 자력선별물, 비철선별에 대해서는 시료채취를 1회 하였다. 30mm미만 시료는 조성별 분리가 어렵기 때문에 협잡물로 가정하고 회분을 측정하여 가연분을 추정하였다. 물리적 조성은 3회 측정한 것을 총괄적으로 환산하여 평균으로 사용하였고 총량은 시스템의 최종 배출지점의 폐기물의 전체량을 측정한 결과로 분석하였다. 물질수지 분석결과 1차 파쇄 후 기준으로 고형연료제품 수율 74.90%, 잔재물 비율 22.66%, 선별물 비율 2.45%을 보였다. 누출량을 포함하여 계산하면 누출물의 비율 11.36%, 고형연료제품 수율 66.39%, 잔재물 비율 20.08%, 선별물 비율 22.17%로 큰 차이가 없었다.

The objective of this study was to determine the CH4 oxidation factor (%) and the CH4 oxidation rate (g m−2 d−1) in landfill cover soil. To quantify in-situ rates of CH4 oxidation, CH4 and CO2 fluxes were measured on a landfill site using the static chamber technique. The CH4 oxidation factor obtained in this study through the mass balance method ranged between 41% and 61%, which is much higher than the Intergovernmental Panel on Climate Change (IPCC) default value of 10%. The higher CH4 oxidation factor derived in this study can be explained by the CH4 bottom flux in addition to the soil texture. The CH4 oxidation factors were observed to increase with decreases in CH4 bottom flux. Therefore, when CH4 bottom fluxes are high in a landfill, using a gas collection system can enhance CH4 oxidation factor. The CH4 oxidation rates were estimated to range from 16.6 g m−2 d−1 to 20.8 g m−2 d−1. In addition, this study was conducted to evaluate the effects of vegetation on the CH4 oxidation factor. The results showed that the CH4 oxidation factors for bare soil, vegetated soil, and soil adjacent to a gas well were 57%, 70%, and 44%, respectively. The results indicate that vegetation on landfill covers can increase the CH4 oxidation factor because of increasing soil porosity.

A mass balance of process was calculated by using the analysis of basic unit and environmental assessment of all the processes of Busan fashion color industry cooperative that operates a combined heat and power plant and a bio treatment plant. The mass balance for the combined heat and power plant was done, based on boiler and water treatment processes while each unit reactor was used for the bio treatment plant. From the results above, a resource recycle network, a treatment flowchart for food waste water/wastewater treatment and a carbon reduction program were established.

The objective of this study was to assess the affects of various solid waste landfill methods on mass balance of carbon. Four lysimeters simulated a conventional landfill (Lys-A), a landfill recirculated only fresh leachate (Lys-B), and two landfills recirculated leachate after pretreating with ASBR (Lys-C and Lys-D) were operated over 1,600 days. Lys-D was recirculated two times of pretreated leachate volume than that of Lys-C. Mass balance of carbon was calculated considering leachate and biogas production for each lysimeter. Lys-C and Lys-D showed that there was an increase of about 3 times in total amount of COD recovered as methane than Lys-A. This results might be attributable to the activated methanogenic bacteria and the high pH of pretreated leachate. In terms of mass balance of carbon, amount of carbon converted to landfill gas in Lys-B (25.20 g/kg-dry waste) was bigger than that of Lys-A (23.64 g/kg-dry waste), while carbon conversion rate to landfill gas for Lys-A and Lys-B showed 4.80% and 4.71%, respectively. It is assumed that only fresh leachate recirculation method can increase amount of carbon converted to landfill gas resulting from the biodegradation of organic carbon in recirculated leachate. However, in comparison with the conventional landfill method, this method should not accelerate hydrolysis of carbon from the wastes. Carbon conversion rate in the landfill recirculated leachate after pretreating with ASBR was increased due to accelerated anaerobic metabolism processes of the microbes. In Lys-C and Lys-D, about 5.9% of carbon was converted to landfill gas. Therefore, it could be seen that the landfill recirculated leachate after pretreating with ASBR could enhance carbon conversion to landfill gas more than the conventional landfill or the landfill recirculated only fresh leachate.

The evaluation of potential submarine groundwater is an important research topic for exploring an alternative water resource. Two different approaches, water budget analysis and Rn mass balance method, were employed to investigate the annual variation of submarine groundwater discharge in 2010 at a marine watershed located at the south-eastern part of Korean Peninsula. In order to obtain reliable hydrological data during study period, temporal and spatial variations of rainfall and soil moisture had been collected and hydro-meterological data such as temperature, humidity and wind speed were collected The runoff response was simulated using SCS-CN method with spatial distributions of landuse and soil texture from GIS analysis. Six different methods were used to estimate the monthly variation of evapotranspiration and field measurements of soil moisture were used to account for the infiltration. Comparisons of infiltration and surface runoff between simulation and water balance with measurements showed coincidence. The water budget analysis and Rn mass balance method provide mean daily submarine groundwater as 5.35 and 4.07 m3/m/day in 2010, respectively.

PM10 samples were collected from July 2007 to Oct. 2007 at Gwaebopdong(inland area) and Dongsamdong (coastal area), in Busan. This paper investigates the contribution of emission sources to PM10 mass in Busan. Source apportionment results derived from the chemical mass balance(CMB) method. A source profiles applied in this study is organized to minimize the collinearity among sources type via statistical method. Source profiles applied in this study utilized a measured value of fine particle directly sampled from metropolitan area such as Seoul and Incheon, After a CMB modeling, sulfate and nitrate related sources among those contributing to PM10 in Busan showed high contribution by 36.53% in Gwaebopdong and 42.02% in Dongsamdong.

Despite the wide distribution of air pollutants, the concentrations of indoor air pollutants may be the dominant risk factor in personal exposure due to the fact that most people spend an average of 80% of their time in enclosed buildings. Researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide(TiO2) coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde and nitrogen dioxide emission rate in indoor environments by TiO2 coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor air quality.