Leading the advancement of water supply technologies through research and development
 
With the aim of producing world-class, healthy, and tasty Arisu, Seoul’s Waterworks Research Institute strives to develop innovative new technologies for delivering clean tap water from purification centers to homes through a safe supply and distribution system.
The Institute focuses on developing sustainable technologies that will help it prepare for the changing domestic and international environment including climate change and water scarcity and create new value and opportunities. Such strong commitment has enabled the institute to acquire 2 international patents and 11 domestic patents, making it a leading organization in the development of Korea‘s water supply-related technology. Equipped with approximately 40 distinguished researchers who are MA or PhD holders and 678 state-of-the-art analysis devices, the institute examines the raw and purified water of Seoul as well as that of other municipalities, playing the role of an internationally accredited examination body under the Korea Laboratory Accreditation Scheme (KOLAS).

Introducing major new technologies studied and developed by the Seoul Waterworks Research Institute
<< Development of a new water supply network analysis and simulation technology
<< Study of measures to reduce water distribution/supply pipe corrosion and improve tap water quality
<< Research and development of an integrated telemetry system
<< Development of a new method to examine the damage in membrane modules that can be used in various fields

Our ultimate goal is to ensure rigorous quality management in all steps, from raw water to every household faucet, and to realize stable water supply that meets the demands of Seoul residents for clean, tasty water.
Many domestic and global changes -- political, social, and economic -- surrounding water supply have suggested the importance of developing key technologies to achieve such goal. Thus, Seoul is making aggressive efforts to develop new technologies that can lead the future water supply system covering the water source all the way to household faucets and help deliver clean tap water.
Among such technologies, the most critical ones for restoring consumer confidence in tap water and providing high-quality service to the citizens include: membrane filtering system for the complete removal of particles generated from diverse industrial developments; optimal management of water pipes; supply system quality management; prevention of pipe corrosion to block any and all potential complaints about rusty water, and; integrated remote metering system, which is an ideal model of IT conversion for the improvement of metering efficiency.

 • 1980 ~ ’90s : With the establishment of the institute in 1989, efforts to lay the foundation for water quality management and technological development began in earnest. Stable management of water quality and supply was the highest priority, leading to the hiring of the relevant personnel and initiation of research.
 • 2000 ~ : Water quality management was the primary focus until 2000. As a result, our analysis technique and capability grew to become the best in Korea. We were able to bring in state-of-the-art analysis equipment thanks to aggressive investments and focus on technological development to improve the quality of Arisu further.
 • 2007 ~ : Our analysis technique has advanced greatly, and it has been recognized to be world-class by various analysis institutions of advanced countries. We began to see some fruits of joint technological developments as well. Furthermore, the development efforts were extended to the sewage system as the need for R&D in the area increased.
 • 2012 ~ : The need to develop leading technologies was highlighted to ensure continued growth of the institute and to secure a future growth engine. To that end, we created an exclusive body for future strategies in charge of early collection of global technological trends and information and suggestion of future direction.
 • 2014 ~ : We set an ambitious goal of becoming a world-class comprehensive water studies center with new transformation initiatives. Various meaningful changes are underway such as hiring of new researchers and organizational restructuring for more effective technological development.

※ Waterworks Research Institute‘s Achievements
Nov. 1989 Appointed as a potable water quality examination body
Apr. 2003 Appointed as the national institution for virus examination
Sept. 2004 Accredited as the national institution for protozoa examination
Jan. 2005 Appointed as the internationally accredited examination body under KOLAS
May 2006 Appointed as an agent for environmental monitoring device accuracy inspection
Jun. 2009 Appointed as the national institution for Norovirus examination
             Appointed as the national institution for membrane module capability certification test

1. Water Supply Network Analysis & Water Quality Simulation

| Background |
Growing need for...
 • Better maintenance and management of water distribution and supply system
 • Enhanced crisis response ability in accordance with the changes in the city environment
 • Application of computer technology to water distribution and supply network management
 • Water quality management technology to meet the citizens’ demand
 
| Research Overview |
 • Distribution and supply network model created

 • Purity fluctuation modeling
Computer simulation and analysis of residual chlorine, disinfection byproducts, residence time, and flow velocity

I Applied Technologies and Their Impact I
 • Set the seasonal standard residual chlorine level at each purification plant.
The standard residual chlorine level in transmitted water can be set in a systematic manner using the pipe network model. This method can help lower the chlorine level at purification plants, thereby getting rid of unpleasant taste or smell in water supply as well as cutting the cost of purchasing chlorine.
 • Conduct hydraulic analysis, water purity assessment, and evaluation by small block.
Examination criteria are categorized into two: water purity concerning safety and hydraulic pressure concerning stability. The evaluated items under water purity include residual chlorine and THMs, which are disinfection byproducts. Items under hydraulic pressure include minimum hydrodynamic pressure, average pressure by block, and pressure fluctuations. Such items help us identify problems in each category and resolve them.
 • Prepare contingency plans.
In case accidents occur in the water supply system and cause damage in large pipes or inflow of contaminants, pipe network analysis can be used to forecast the impact of damage in transmission pipelines and power interruption at pressurizing stations, expected recovery time, and impact of contaminant inflow to be applied in disaster or accident response plans.
 • Enhance pipe network maintenance and management capabilities.
The digital pipe network model can be used for hydraulic pressure and residual chlorine management and to contribute to the improvement of the overall water supply management capability.

Researcher in charge: Jaechan AN, Distribution & Supply Studies Division, Waterworks Studies Department, Waterworks Research Institute, 02-3146-1823, anjchan@seoul.go.kr

2. Measures to Reduce Pipe Corrosion and Improve Tap Water Purity

| Background |
 • To curb the corrosion of water pipes, the United States and European countries have water purity specialists manage the pH level at purification centers or use corrosion inhibitors. In particular, the US has been using phosphate-based corrosion inhibitors at purification plants since the 1930s; with the enactment of the <Lead and Copper Rules> in 1991, the number of purification facilities using corrosion inhibitors increased significantly.
 • Korea does not yet have anti-corrosion measures put in place at the purification center level to prevent rusty water. For the more effective prevention of rusty water, Korea should also make water suppliers manage anti-corrosion methods as is the case in the US, Europe, and Japan. It also needs to develop new technologies for monitoring and reducing tap water pipe corrosion at the purification plants.
 
| Research Overview |
 • Langelier Saturation Index (LI) assessment of the Han River system
US and Germany maintain their LI level at 0, whereas Japan keeps its LI level at -1.0 to 0. The Korean government does monitor LI but is still studying what the ideal range of LI should be. Purified water has greater potential to cause corrosion due to the chlorine and coagulants injected into the purification process, which cause the pH level to drop. If an alkaline chemical is added toward the end of the purification process, corrosivity of water drops since the chemical neutralizes the water.
 • Suggestion of LI monitoring
We suggested that the Ministry of Environment include tap water LI in the list of water quality assessment categories to manage better ductile cast iron pipes with cement lining, prevent old water pipes at homes from causing rusty water, and reinforce the safety of corrosion inhibitors currently managed in small units such as apartment complexes.
 • Development of corrosivity index and corrosion prevention technology
To prepare for the introduction of LI management standards, Seoul installed the first ever pilot plant for corrosivity management in 2007. The city obtained three new patents for techniques such as the “Method of Corrosion Inhibition of Water Pipe (18 January 2008),” “Method for Corrosion Prevention of Water Distribution Systems by Lime Slurry (14 November 2008),” and “Method for Supplying Water with Controlled Corrosive Characteristics (25 August 2010).” Such techniques are the first case in the world to use carbon dioxide to dissolve limewater in tap water completely. They can be differentiated from the techniques used in the US or Japan since they ease the burden of workers at plants using hydrated lime powder; they can also turn 99.9% hydrated lime into calcium.

• Total cost of the project: 400 million KRW (cost of constructing the corrosion management plant)
 
| Implementation Experience and Know-how |
 • At the initial stage of the project, lime water did not dissolve at all when 0.13% was supposed to theoretically. Nonetheless, innovative technological development led to the increase of Ca solubility level to up to 40ppm.
 • We suggested that the Ministry of Environment add new LI monitoring categories (1 September 2005). Such suggestion laid the foundation for potential corrosivity management in the future, since it led to the enactment of the relevant act on 22 December 2011 and its enforcement on 1 July 2012.
 
| Research Outcome |
 • After assessing the LI of all pipes in the Han River system, we have asked the Ministry of Environment to add LI in its purity assessment criteria to extend the life span of water pipes and prevent the sending of rusty water to faucets at home. Consequently, LI was added to the ministry‘s monitoring list on 1 July 2012. The ministry and the institute are working on a joint research project to develop a new index corrosivity management that suits the Korean water conditions better.

Researcher in charge: Yeongbok PARK, Water Distribution and Supply Studies Division, Waterworks Studies Department, Waterworks Research Institute, 02-3146-1824, ybpark0510@seoul.go.kr

3. Integrated Telemetry System

| Research Overview |
 • Integrated telemetry is a process of sending and receiving the usage data for water, electricity, gas, and other utility bills altogether at remote points. This project used power line communication to combine telemetry systems for water, electricity, and gas at the lowest cost. Using power lines to communicate requires data to be sent from water meters to digital electricity meters. Thus, the data was sent through low-power wireless communication. The integrated telemetry system structure is illustrated below.

At least 100 houses in Yangcheon-gu, Mok-dong had new meters installed. The new system was connected to 86 15mm faucets and 16 20mm faucets. We monitored the measurements from each faucet, identified the reasons for any and all abnormalities through on-site surveys, provided solutions to the problems, and analyzed the outcome of the pilot operation. To guarantee the compatibility of the integrated telemetry system, we teamed up with the Korea Electric Power Research Institute (KEPRI) to study and design the digital water meter protocol and wireless communication protocol. The protocols developed through the joint study were applied to the integrated telemetry simulator for 43 days to check whether data moves from digital water meters to the main server without any issue.
 
| Research Outcome |
 • During the pilot period, the monthly average success rate of communication varied between 85.4% at the lowest and 95.9% at the highest. The average success rate was 91.9% throughout the period. Between January and June 2009, the average success rate of participating companies was 99.3% at the highest and 86.3% at the lowest. The rate of successful connection in water supply telemetry rose to a reliable level thanks to the development of a new telemetry device technology.
 • After the pilot operation, we found that the direst challenge was ensuring the interoperability of digital water meters, mobile metering devices, and digital electricity meters. Thus, we designed a protocol for digital water meters and one for wireless communication jointly with KEPRI. We tested the feasibility of the protocols by applying them to the water telemetry simulator in our lab. After 43 days of pilot operation, we confirmed that the initial registration data were sent from metering devices to the server without any problem. We also found no issue in data linkage between the two protocols as well as in the measured data and connectivity.
 • An integrated telemetry system using power line communication is unprecedented. This project confirmed that the integrated metering system has technical strength compared to the independent water supply metering system. Certain sections of the network use cable communication since the underground water meters do not provide a favorable environment for wireless communication. This reduces the range of wireless communication and renders repeaters for improving wireless connectivity unnecessary; hence the less installation and maintenance efforts.

Researcher in charge: Hyo-il KIM, Water Distribution and Supply Studies Division, Waterworks Studies Department, Waterworks Research Institute, 02-3146-1825, tomcat-khi@seoul.go.kr
 

4. Membrane Module Damage Assessment Technology for Broad-range Application

| Background |
In current water treatment centers, raw water passes through a flocculation tank and a sedimentation basin. Sand filters are commonly used to remove contaminant particles in the water during the process. Note, however, that sand filters cannot remove organic particles, viruses, protozoan cysts, or other particles smaller than 1um since they are meant for the removal of those larger than 10um. For such reasons, membrane integrity tests are conducted to check if the membrane can remove pathogenic microorganisms or whether it has any damage. A damaged membrane cannot remove particles effectively but adversely affects the purity of water. Therefore, the damage should be detected in the early stage for repair or replacement in serious cases. Note, however, that damages are invisible to the naked eye, making it extremely difficult for them to be detected earlier.
To resolve such issue, we have developed a new integrity testing method of reducing the surface tension of liquid solution, which allows more accurate testing results at lower pressure.
In this method, citric acid for cleaning the membranes is used to adjust the surface tension. It increases the resolution of the direct integrity test and enables detecting small-size rupture or damage using lower pressure. Pressure-drop testing is a convenient method that can be easily applied to actual purification plants.
 
| Research Outcome |
 • In a direct integrity test for validating high removal credits of a membrane module, a method using the reduced surface tension of liquid can be applied in the following steps:

- Create a solution by mixing water and a chemical reducing the surface tension of water.
- Inject into the filtration membrane module the solution for lowering surface tension.
- Close the raw water supply valve and filtered water supply valve of the membrane module while keeping the air pressure supply and discharge valves open.
- Close the air pressure supply valve: Measure changes in air pressure after a certain duration of time.
- Compare the measured air pressure with a preset standard value to detect possible damage in the membrane. The pressure-drop method enhances the resolution of the membrane integrity test.

 
| Application and Impact |
This method can be applied to integrity tests in any field utilizing a membrane module. It lets the users conduct a direct integrity test of the membrane filter during its chemical cleaning or maintenance cleaning process; thus, it can be adopted at any site that uses membrane filters.
 
| Impact of the applied technology |
Pressure-drop testing is a practical method with enhanced resolution, which enables conducting direct integrity test and chemical cleaning of membrane filters at the same time. Using the method, damage on the membrane surface can be easily identified and fixed during its chemical cleaning process so that the damage does not lead to the degradation of water purity.

Researcher in charge: Kwangje LEE, Water Treatment Studies Division, Waterworks Research Institute, 02-3146-1821, lkjnara@seoul.go.kr

 • Patent : 16 items (13 obtained, 3 in progress)

 • New Excellent Technology (NET) certification: 3 items (completed)

How has the Waterworks Research Institute supported other local water supply quality examinations?
 
 • The Waterworks Research Institute has shared water quality analysis methods with local water suppliers including membrane module test, protozoan, advanced water treatment, sample analysis, potable water quality standards, virus (purified water) and water treatment solution testing, etc.
 • In 2013, 117 organizations including Wonju, Gangwon-do received support from the institute, generating 79.414 million KRW in profit. As of June 2014, 68 organizations including Hanam and Gyeonggi Province received the institute‘s support, with 43.495 million KRW worth of profit generated.