As an advanced study on the method of calculating the target revenue water ratio of local waterworks through the leakage component analysis method proposed by Kim et al. (2022), this study developed a model to calculate the achievable revenue water ratio within the specified project cost, the required project cost to achieve the specified target revenue water ratio, and the economically appropriate target revenue water ratio level by considering the leakage reduction cost and leakage reduction benefit for each revenue water ratio improvement strategy, and conducted an applicability evaluation of the developed model using actual field data. The procedure for calculating the target revenue water ratio of local waterworks considering economics proposed in this study consists of three stages: physical data linkage model construction, leakage component analysis, and economic analysis, and the applicability was evaluated for Zone H with branch type and the Zone M network type. As a result of the application, it was calculated that approximately 32.5 billion won would be required to achieve the target revenue water ratio of 70% in the Zone H, and approximately KRW 10.5 billion would be required to achieve the target revenue water ratio of 75% in the Zone M. If the business scale of Zones H and M was corrected to 10,000 ㎥/day of water usage, the required project cost for a 1% improvement in the revenue water ratio of Zone H was calculated to be 0.7642 billion won and 0.4715 billion won for Zone M.

This study set up the revenue water ratio that could be achieved within the range of the expenses of the water distribution network maintenance project, developed an analysis methodology that could estimate the additional project quantity to achieve the target revenue water ratio of 85% and applied and verified that to S. City. This methodology allowed the distribution of the leakage quantity for each leakage component by the pipeline through the total revenue water account balance analysis and BABE approach and the redistribution into the calculated leakage quantity more accurately through a step test. In addition, the level of reduction in leakage and the quantity of the project were estimated before and after the application of four strategies for the promotion of the revenue water ratio presented by IWA, according to the leakage components by the pipeline. As a result of the application of this analysis method to S. City, it would be possible to achieve up to the revenue water ratio of 81.0%, which was 74.7% in the beginning, if the water distribution network maintenance project was promoted within the range of the project expenses, and to achieve the revenue water ratio of 85.0%, the goal of the project, it would be necessary to replace the pipeline of 22.2% of the entire pipelines in the target area. As a result of the re-estimation of the revenue water ratio achievable, applying the actual water distribution network maintenance quantity in the scope of the business with the results of this analysis, the revenue water ratio was 81.7% while the actually measured revenue water ratio was 82.3%. Thus, the reliability of this analysis method could be secured to some extent.

In this study, air scouring cleaning was selected and applied among 5 small blocks (S1~S5) in domestic S cities to analyze the cleaning effect of particles causing discoloration. In order to identify the cleaning effect, 10 locations were selected as water quality investigation point, such as the stagnant or water mains ends. Removal of solids, variation of particle components, weight and concentration were analyzed. And the level of the cleanness of the surface inside water mains using endoscope was investigated. As a result of analysis, the solids discharged after cleaning were mainly sand and gravel, pieces related to pipe materials, and corrosion products. As a result of analyzing the concentrated particles of the filter before and after cleaning, it was found that the change in discoloration on the filter was large. In addition, as a result of comparing the weight and the concentration of the particles, it was found that the particles causing discoloration were significantly removed after cleaning. From the results of the endoscopy, it was confirmed that most of the precipitated and accumulated dark yellow discoloration matters inside water mains were removed through cleaning. Therefore, it seems that the particles causing discoloration in water decreased after cleaning. Therefore, it is expected that, if properly cleaning was applied, matters that cause discoloration can be removed from the water mains, and customer's complaints can also be reduced through water quality improvement.

This study describes a reasonable planning method for water meter replacement which can minimize the metering under-registration for an increasement of revenue water. The increment analysis of real water usage was used to establish a replacement plan. The meter replacement database collected from K City was used as the basis of this analysis. The database included 964 connections of domestic and non-domestic consumers that had their meter replaced by aging at 2011.The result showed that the corelation between unregistered water volume and water meter age was lower than commonly expected where the current criteria of replacement is only water meter age(8 years) excluding the meters older than 13 years. And in the analysis result of water usage for 8 years, the total amount and increment of water usage had a significant effect on unregistered water volume. However the relation was different tendency as a total volume and slope of increment. In case of total water volume was larger than 10,000 , larger than 7,000 and increment of 0.0 ~ -0.3, larger than 6,000 and increment more than -0.3 were analysed to need a replacement because of metering under-registration.

The water distribution system should be invariably operated on continuous pattern for 24 hours a day. Occasionally, it is not practically possible to operate for 24 hours due to water shortage or financial constraints. Therefore an intermittent water supply is unavoidable in water shortage area and developing countries.But the intermittent water supply can introduce large pressure forces and rapid fluid accelerations into a water supply network. These disturbances may result in new pipe failure, leakage and secondary contamination.This paper proposed an improvement methodology to prevent the disturbances by intermittent water supply. For the study, the hydraulic variation of intermittent flow in water distribution system was measured and analyzed in the field by comparing with simulation of hydraulic model. Installations of control valves such as, pressure reducing and sustaining and air valves were employed for pressure and flow control. The effectiveness of the methods are presented by comparing hydraulic conditions before and after introducing the proposed solutions.