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.

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.

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.

공업용수의 경제적 가치에 대한 정보는 학술적 연구 분야뿐만 아니라 정책평가 영역에서도 광범위하게 요구되고 있다. 이에 본 연구에서는 경제이론에 근거하여 수종별 공업용수의 경제적 가치를 추정하고자 한다. 이를 위해 본 연구에서는 전국 국가산업단지 및 지방산업단지 등에 위치한 제조업체 1,017개를 대상으로 한 설문조사를 통해 수집한 자료를 이용하여 공업용수의 경제적 가치를 추정을 시도하되 원수·침전수·정수 등 수종별로 구분된 경제적 가치를 도출하고자 하였다. 분석결과, 2010년 말 기준 공업용수의 수종별 한계생산가치는 정수가 1,861.95(원/m3), 침전수가 896.76(원/m3), 원수가 769.24(원/m3)로 추정되었다. 이러한 분석결과는 한국개발연구원이 수자원부문사업의 예비타당성조사 표준지침 수정·보완연구(제4판)의 보완을 위한 공업용수 공급편익 산정요령 가이드라인(2011)에서 2003년 산업총조사 자료를 이용하여 분석한 결과로 제시한 공업용수 침전수의 한계생산가치 885.1원/m3(침전수, 2010년 말 기준)과 비교할 때 별 차이가 없다. 이러한 점은 현재 한국개발연구원에서 현재 적용하고 있는 공업용수 침전수의 공급편익 원단위가 적절함을 시사한다.

본 연구는 수자원정책의 효율성 제고를 위한 정책 방안 마련의 토대를 제공하고자 제조업체에서 투입요소로 사용하고 있는 공업용수의 기술적 효율성을 추정하였다. 이를 위하여 자료포락분석(DEA:Data Envelopment Analysis)기법을 이용하였으며 분석 결과에 의하면 공업용수의 기술적 효율성은 전 산업 평균이 0.407로 추정되어 모든 투입요소가 가변적인 경우의 연구 사례에 비하여 낮은 추정치를 보여준다. 이는 공업용수에 대한 비용이 다른 투입요소

본 연구는 수자원정책의 효율성 제고를 위한 판단 자료 제공을 목적으로 업종별 공업용수의 한계생산가치 및 공업용수의 가격탄력성을 추정하였다. 두 가지 형태의 생산함수를 설정하여 추정한 공업용수의 한계가치 및 가격탄력성을 추정 결과를 보면 공업용수의 한계가치는 산업별로 차이가 있으나 공업용수의 평균 가격에 비하여 매우 큰 것으로 추정되었으며 가격탄력성 추정결과는 가격 현실화 정책 효과가 있음을 보여주고 있다.