This study develops a model to determine the input rate of the chemical for coagulation and flocculation process (i.e. coagulant) at industrial water treatment plant, based on real-world data. To detect outliers among the collected data, a two-phase algorithm with standardization transformation and Density-Based Spatial Clustering of Applications with Noise (DBSCAN) is applied. In addition, both of the missing data and outliers are revised with linear interpolation. To determine the coagulant rate, various kinds of machine learning models are tested as well as linear regression. Among them, the random forest model with min-max scaled data provides the best performance, whose MSE, MAPE, R2 and CVRMSE are 1.136, 0.111, 0.912, and 18.704, respectively. This study demonstrates the practical applicability of machine learning based chemical input decision model, which can lead to a smart management and response systems for clean and safe water treatment plant.

본 연구는 해양산업시설에서 배출되는 위험·유해물질(Hazardous and Noxious Substances) 중 아연을 대상으로 국내 서식종을 기반 으로 한 독성시험을 수행하고, 그 결과를 활용하여 국내 실정에 맞는 아연의 해양 수질 준거치(Marine Water Quality Criteria)를 제안하였다. 시험생물은 국내 연근해에 분포하고 산업적으로 유용하며, 표준 시험방법이 존재하는 종을 우선으로 5개의 분류군(Algae, Rotifer, Crustacean, Mollusc, Fish)의 총 10종을 선정하여 독성시험을 수행하였으며, 급·만성비(Acute-Chronic Ratio) 산출을 위하여 무척추동물, 어류 분류군에 대한 만성독성시험을 수행하였다. 국내종 독성시험에서 산출된 독성값을 활용한 수질준거치는 US EPA의 CCC (Criterion Continuous Concentration) 산출 기준으로 9.56 ㎍/L, 호주/뉴질랜드의 산출 기준으로 15.50 ㎍/L 로 나타나 호주/뉴질랜드에서 권고하는 기준인 14.40 ㎍/L 와 유사하였다. US EPA 및 호주/뉴질랜드는 자국의 생태독성 데이터베이스(US EPA Ecotox Database, Australasian Ecotoxicology Database)를 보유하고, 신뢰도 높은 독성값들을 생성하여 수질 기준 및 산출 기준을 갱신하고 있다. 한편, 국내에서는 국내종 기반 급성 독 성값을 적용하고 있지만, 중요한 산출 지표인 급·만성비는 US EPA 또는 유럽의 결과값을 활용하여 해양 수질 준거치를 산출하고 있으며, 국내의 생태독성 자료 또한 제한적인 실정이다. 따라서, 국내 해양 서식종을 기반으로 한 지속적인 독성시험과 준거치 설정 체계를 확보하 여 국내 해양생물과 생태계를 보호할 수 있는 해양 수질 준거치 도출이 필요할 것으로 판단된다.

본 연구는 IMO 선박평형수관리협약과 관련하여 선박평형수처리시스템(BWMS) 산업에 대한 한국의 산업경쟁력 현황과 향후 발전방향을 제언하기 위하여, BWMS 관련 무역데이터를 기반으로 현시비교우위지수와 무역특화지수로 비교·분석하였다. 친환경선박에 대한 국제적 관심이 확대됨에 따라 IMO는 선박기인 오염물질 해양배출과 관련된 논의 및 협정 체결이 지속적으로 증가하고 있다. 동 협약의 이행국가들은 BWMS 산업이 높은 시장진입 장벽과 선도 시장진입자의 시장점유율 확대를 위해 경쟁하고 있으며 BWMS는 친환경선박 분야의 주요산업으로서 각 국가는 기술개발 및 산업경쟁력확보를 위해 노력하고 있다. 한국은 2019년 10월 기준(BWM.2/Circ.34/Rev.8) 최종 승인 받은 BWMS 전체 45개 중 17개(약 38 %)를 차지하고 있다. 동 산업의 시장점유 현황을 파악하기 위하여 상품코드 HS842219, HS84212, HS89가 부여된 무역데이터를 기반으로 현시비교우위지수와 무역특화지수를 산출 및 비교한 결과, 한국은 전 세계 대상으로 BWMS 시장 점유가 비교우위이나 독일, 덴마크 등의 국가에 비해서는 상대적 열위인 것으로 분석되었다. 그럼에도 불구하고 다수의 IMO 승인기술 건 수, 국내 승인기관 보유 등의 산업생태계가 조성되어 있어 향후 BWMS 시장 경쟁력이 강화될 가능성이 높은 것으로 분석되었다.

Heavy metals in stream water and sediments around industrial complex were studied in order to assess the contamination and to identify the potential source of metals. High variability has been observed for both dissolved and particulate phases in stream water with coefficient of variation (CV) ranging from 1.3 to 2.8. The highest metal concentrations in both phases were observed in Gunja for Ni and Cu, in Jungwang for Zn and Pb and in Shiheung for Cd, respectively. These results indicate that the different metal sources could be existing. The concentrations of the heavy metals in sediments decreased in the order of Cu>Zn>Pb>Cr>Ni>As>Cd>Hg, with mean of 2,549, 1,742, 808, 539, 163, 17.1, 5.8, 0.07 mg kg-1, respectively. Mean of metal concentrations (except for As) in sediments showed the highest values at Shiheung stream comparing with other streams. In sediments, the percent exceedance of class II grade that metal may potentially harmful impact on benthic organism for Cr, Ni, Cu, Zn, Cd, Pb was about 57%, 62%, 84%, 60%, 68%, 81% for all stream sediments, respectively. Sediments were classified as heavily to extremely polluted for Cu and Cd, heavily polluted for Zn and Pb, based on the calculation of Igeo value. About 59% and 35% of sediments were in the categories of “poor” and “very poor” pollution status for heavy metals. Given the high metal concentrations, industrial wastes and effluents, having high concentrations of most metals originated from the manufacture and use of metal products in this region, might be discharged into the stream through sewer outlet. The streams receive significant amounts of industrial waste from the industrial facilities which is characterized by light industrial complexes of approximately 17,000 facilities. Thus, the transport of metal loads through streams is an important pathway for metal pollution in Shihwa Lake.

This study derived the unit of industrial water usage reflecting the latest industry trends. Available for establishing plans such as the master plan for water supply system and analyzed changes in the basic unit by a comparison with the current basic unit values. This study analyzed 4,038 samples with a sampling error of less than 1.5 % at the 95 % confidence level after removing outliers according to a log-normal distribution. As a result, the unit of industrial water usage per site area in the whole manufacturing industry was 7.11 m3/1,000m2/d. The ten industrial categories (C10, C13, C20, C21, C22, C25, C27, C30, C32, C33) showed a similar unit value compared to before, and the four industrials categories (C11, C17, C22, C31) showed a more unit value than before. With regard to the nine industrial categories (C14, C15, C16, C18, C19, C24, C26, C28, C29), the unit value decreased. Cases that companies examined before were the same as the companies examined in this study were analyzed. The result that the changes in the unit industrial water usage were reasonable was obtained. However, in some industrial categories (C17, C14, C24, C29), the unit value was changed by a small number of companies with large-scale water use or unit value of sampling had a large deviation. It was considered necessary to survey them periodically. The unit of industrial water usage derived by the survey in this study reflects the current industrial trends in 2016. Water use in manufacturing companies has continuously changed by the development of manufacturing technologies and simplification of manufacturing processes. In order to deal with this, it is considered necessary to survey the usage of industrial water periodically from a long-term perspective.

The sewage and wastewater (SAW) are a well-known major source of eutrophication and greentide in freshwaters and also a potential source of thermal pollution; however, there were few approaches to thermal effluent of SAW in Korea. This study was performed to understand the behavioral dynamics of the thermal effluents and their effects on the water quality of the connected streams during winter season, considering domestic sewage, industrial wastewater and hot spring wastewater from December 2015 to February 2016. Sampling stations were selected the upstream, the outlet of SAW, and the downstream in each connected stream, and the water temperature change was monitored toward the downstream from the discharging point of SAW. The temperature effect and its range of SAW on the stream were dependent not only on the effluent temperature and quantity but also on the local air temperature, water temperature and stream discharge. The SAW effects on the stream water temperature were observed with temperature increase by 2.1~5.8℃ in the range of 1.0 to 5.5 km downstream. Temperature effect was the greatest in the hot spring wastewater despite of small amount of effluent. The SAW was not only related to temperature but also to the increase of organic matter and nutrients in the connected stream. The industrial wastewater effluent was discharged with high concentration of nitrogen, while the hot spring wastewater was high in both phosphorus and nitrogen. The difference between these cases was due to with and without chemical T-P treatment in the industrial and the hot spring wastewater, respectively. The chlorophyll-a content of the attached algae was high at the outlet of SAW and the downstream reach, mostly in eutrophic level. These ecological results were presumably due to the high water temperature and phosphorus concentration in the stream brought by the thermal effluents of SAW. These results suggest that high temperature of the SAW needs to be emphasized when evaluating its effects on the stream water quality (water temperature, fertility) through a systematized spatial and temporal investigation.

In this study, the land use is analyzed by using the SWMM-LID (Low Impact Development) program to minimize the environmental damage caused by the development. In order to effectively utilize pre - development hydrological conditions, we analyzed the land use of existing industrial complex. The study areas selected were a completed industrial complex and an ongoing industrial complex in order to effectively identify the characteristics of the industrial complex and the water circulation system. Numerical simulation used SWMM-LID to enable quantitative hydrological impact assessment of penetration, storage facilities and LID planning elements. In the case of natural conditions, the infiltration amount was 16.3% and 1.5% of the total rainfall at B, C point, respectively. However, after applying the existing land use plan, the infiltration amount at point B was 12.1% and at point C was 3.9 %. In the case of point B, the amount of infiltration decreased due to the development of greenery as an impervious site. On the other hand, the amount of infiltration at point C increased as the existing industrial complex was replaced by greenery. Therefore, high infiltration amount can be secured when land use plan is redeveloped in green areas or parks in areas where the permeability coefficient is high according to the ground conditions in the complex. Two types of bio-polymer soil were developed to increase the LID effect and were tested to compare typical soil with these bio-polymer soils.

Peak load rate(i.e., maximum daily flow/average daily flow) has not been considered for industrial water demand planning in Korea to date, while area unit method based on average daily flow has been applied to decide capacity of industrial water treatment plants(WTPs). Designers of industrial WTPs has assumed that peak load would not exist if operation rate of factories in industrial sites were close to 100%. However, peak load rates were calculated as 1.10~2.53 based on daily water flow from 2009 to 2014 for 9 industrial WTPs which have been operated more than 9 years(9-38 years). Furthermore, average operation rates of 9 industrial WTPs was less than 70% which means current area unit method has tendency to overestimate water demand. Therefore, it is not reasonable to consider peak load for the calculation of water demand under current area unit method application to prevent overestimation. However, for the precise future industrial water demand calculation more precise data gathering for average daily flow and consideration of peak load rate are recommended.

(주)휴비스워터는 산업용 초순수 생산에 국내최초로 분리막 공정을 적용하여 발전, 전자, 자동차 산업 등에 공급해 오고 있다. 특히 국내 최초로 대형 EDI 모듈을 자체개발하여 상업화 하였으며 전처리용 MF 중공사 분리막 및 모듈을 개발하여 다수의 산업현장에 공급하고 있다. 본고에서는 산업용 초순수 생산을 위한 EDI의 적용사례를 중심으로 발표를 하고자한다. 더불어 (주)휴비스워터에서는 1 m³/hr 규모의 해수담수용 FO-RO hybrid pilot 시스템을 삼척그린파워 건설현장에서 운전하고 있으며, 현재까지 운전된 결과를 소개하여 앞으로 FO공정의 발전방향을 공유하고자 한다.

A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

울산공단지역과 지리산지역에서 소나무림의 강우로부터 산림내 유입되는 수간류, 수관통과우, 임외우의 이온성분을 조사하여 그 특성을 분석하였다. 울산공단지역에서는 pH가 지리산지역에 비해 수간류, 수관 통과우, 임외우 모두 낮아 대기오염의 영향으로 추측할 수 있었다. EC는 수간류, 수관통과우, 임외우 모 두 울산공단지역이 높았으며, 수간류와 수관통과우에서는 양지역이 2배 정도 차이가 있었다. 이온성분은 울산공단지역에서 대체적으로 높았으며, 수간류에서 지역차가 2배 이상 나타났으며, 특히 Ca2+, Mg2+ 이 온의 농도가 지역간 차이가 높게 나타났다. 음이온 성분은 두 지역 모두 SO4 2->NO3 ->Cl- 순으로 나타났 으며, 지역간 차이가 가장 큰 이온은 SO4 2-으로써 수간류에서 토양으로 유입되어 토양의 산성화를 초래할 뿐만 아니라 산림생태계 전반에 영향을 미칠 수 있다.

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time.However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium,has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects thehuman body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromiumin cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different SiO2 , Al2O3,and Fe2O3 sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed,and the raw meal was burnt at about 1450oC in a furnace with an oxidizing atmosphere. The part in the raw materials of theclinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the contentof clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine Cr+6 formation of theclinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because thechromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with thechromium. Also, the chromium was converted into hexavalent chromium in the burning process.

본 연구는 하수를 공업용수로 재이용하기 위한 분리막 시스템 적용에 관한 연구이다. 정밀여과와 역삼투시스템으로 구성된 bench scale 실험장치를 이용하여 하수처리장 현장에서 실험을 수행한 결과, 정밀여과 시스템은 이온성분은 제거할 수 없었으나 SS를 70% 이상 처리할 수 있어 처리수는 직접냉각수로 재이용이 가능하였다. 그리고 역삼투 시스템은 SS는 물론 이온성분도 95% 이상 제거할 수 있어 처리수는 간접냉각수 및 제품세척수로 사용이 가능하였다. 100 m3/일 용량의 pilot Plant를 제작하기 위해서는 정밀여과 모듈은 20개, 역삼투 모듈은 12개가 필요하였다.

Recently with the rapid development in the industries such as an iron mill and chemical plants, these are enlarged by the use of the piping. This piping was encountered the stress corrosion cracking(SCC) because of stress by water pressure and residual stress of welding etc. under industrial water. In this paper, the behaviour of stress corrosion cracking on the weld zone of steel pipe piping water(SPPW) were investigated according to pre-heat before welding in natural seawater(specific resistance : 25Ω-cm). The main results obtained are as follows :1) The stress corrosion cracking for SPPW and SB 41 is most ready to propagate in heat affected zone of weldment. 2) The SCC sensitivity of SPPW on weldment is more susceptible than that of SB 41. 3) The stress corrosion cracking growth of heat affected zone is delayed by the preheat and dry of base metal and electrode before welding.

Recently, with the rapid development in the industries such as an iron mill and chemical plants, there is enlarged by the use of the piping. Sepecially, the piping connected with a fluid, if it is increase the speed of running fluid, ought to generate cavitation phenomenon with unbalanced pressure. So, the cavitation phenomenon cause serious damage of the piping, because it generate erosion and corrosion in the piping. In this study, the steel pipe piping water (SPPW) and SPPW on weldment were tested by using of cavitation-erosion test apparatus with nozzle and were investigated under the marine environment of liquid. (specific resistance : 25 Omega. cm) The main results obtained are as follows : 1) The total weight loss and weight loss rate of affected zone of weldment by corrosion-erosion in the sea water are more increased than that of base metal. 2) The electrode potential by corrosion-erosion in the sea water becomes less noble than that of base metal, and current density is more increased. 3) As time goes by, the total weight loss and weight loss rate by cavitation erosion-corrosion in air-liquid 2 phase flow become more increased then those in only liquid solution. but these values turn to be decreased.

산업단지에 입주한 업체에서 발생되는 폐수는 업종별로 성상이 다양하고 같은 성분이라도 수십배의 함량차이를 보이고 있어 대부분의 산업단지 폐수종말처리장에서는 안정적인 처리 효율을 유지하기 위해 업체별로 개별 처리한 처리수를 폐수종말처리장으로 유입시켜 처리하고 있는 실정이다. 따라서 폐수 발생 업체들은 폐수를 생물학적 방법, 물리･화학적인 방법을 이용하여 폐수를 처리하고 있으며, 화학적 처리 방법을 채택하고 업종이 많은 것으로 알려져 있다. 주를 이루고 있다. 한편 폐수 처리 과정에서 발생되는 슬러지는 자체 처리하는 경우도 있지만, 대부분 탈수 처리한 후에 지정 페기물 해당 여부에 따라 상이한 방법에 의해 위탁 처분되고 있다. 그러나 이러한 폐수 처리 과정에서 발생되는 슬러지의 성상에 대해서는 지정 폐기물 해당 여부를 판단하기 위한 자료만 있으며, 지정 폐기물 기준 항목 이외의 성분에 대한 다양한 정보와 축적된 자료가 전무하여 발생 슬러지에 대한 체계적으로 관리하기에는 한계가 있다. 따라서 산업단지내 업종별 발생 슬러지의 특성을 파악하고 이들 슬러지 관리 체계의 구축을 위한 기초적 자료를 확보하기 위해 대구지역 S 산업단지내에 입주하고 있는 폐수 발생 업체 중 18업체(6개 업종)에 대해 원수, 처리수 및 슬러지를 채취하여 그 성상을 비교･검토하였다. 연구 대상 업체에 대한 슬러지를 조사･분석한 결과, 염색 업종은 상대적으로 알루미늄의 함량이 높은 것으로 나타났으며, 일부 업체는 100g/kg을 상회하였다. 특히 도금 업종에서는 300g/kg을 상회하는 업체도 있는 것으로 나타났다. 철은 조립 금속 업종에서 가장 많이 함유된 것으로 나타났으며, 칼슘의 함유량은 대부분의 업종에서 높게 나타났다. 그리고 석유 화학 업종이 타 업종에 비해 인의 함유량이 높은 것으로 나타났다, 검토한 업종별 슬러지에서 100g/kg을 상회하는 함유량을 보인 성분은 알루미늄, 철, 크롬, 칼슘이었다. 알루미늄, 철, 칼슘은 대부분 폐수의 처리 과정에서 투입된 응집제에서 기인된 것으로 판단되며, 크롬은 도금 업종에서 배출된 것으로 나타났다.

In this study, industrial by-products such as desulfurization gypsum and C12A7-based slag was used for activating recycling water. Consequently, it was verified via test that workability and compressive strength were not affected on activated-sludge.