M.T. Amin, M.Y. Han

1. SNU RRC 6th World Water Forum KSU RFA M.T. Amin, M.Y. Han Socially and economically acceptable drinking water supply from rooftop rainwater and improved solar disinfection

2. Contents 1 Introduction 2 Materials and Methods 3 Results and Discussion 4 Conclusions

3. Introduction

4. Background < Tailand > < Uganda > • Lots of countries have water shortage problems over the world • Rainwater harvesting (RWH) can be alternative water resource to these countries • Because RWH system is simple to install and manage, this system has been spread to water shortage areas. Sited from “ELLIAS SAIDIN and AMINUDDIN BAKI, RAINWATER HARVESTING: POTENTIAL ALTERNATIVE WATER RESOURCES IN MALAYSIA, WATER MALAYSIA 2009” SNU RRC 6th World Water Forum KSU RFA

5. What is rainwater harvesting system? Drinking Cleaning Emergency Gardening SNU RRC 6th World Water Forum KSU RFA

6. Rainwater as drinking water ? • At least one-third of the population in developing countries has no access to safe drinking water • Rainwater can be used as drinking water if microbial contamination is controlled. Simple disinfection method can make and supplysafe drinking water by rainwater SNU RRC 6th World Water Forum KSU RFA

7. Solar Disinfection (SODIS) • Inactivation of microorganisms by UV-A-radiation and thermal treatment • Suited for providing safe drinking water in rural and semi-urban communities in developing countries • Promoted by the World Health Organization (WHO) Solar and Longwave Radiation Infrared UV Reflection and Back-Radiation DO/pH Temp. Used PET bottle Attenuation By Plastic? Pasteurization Cellular Breakdown Conduction SNU RRC 6th World Water Forum KSU RFA

8. Developing Solar Disinfection a. SODIS b. W-SODIS c. SOCODIS e. I-SOCODIS d. W-SOCODIS SNU RRC 6th World Water Forum KSU RFA

9. Limitation of SODIS • Few scientific and engineering data for rainwater disinfection • Only strong sunlight radiation for about 6~8 h daily is adequate for the complete disinfection W-SODIS (Wrapping Solar Disinfection) system SOCO-DIS (Solar Collector Disinfection) system • Improving SODIS to achieve more concentrated temperature effects • Improving SODIS to achieve more concentrated sunlight radiation SNU RRC 6th World Water Forum KSU RFA

10. Limitation of SOCO-DIS • Sunlight radiation for about 6~8 h daily is not adequate for the complete disinfection in the weak weather W-SOCO-DIS (Wrapping Solar Collector Disinfection) system I-SOCO-DIS (Improved Solar Collector Disinfection) system • Improving SOCO-DIS to achieve more concentrated temperature effects and sunlight radiation • Improving SOCO-DIS to achieve more high pH SNU RRC 6th World Water Forum KSU RFA

11. Materials and Methods

12. Sample collection site * RWH : Rainwater harvesting system SNU RRC 6th World Water Forum KSU RFA

13. Outline of experiment a. SODIS Seoul, Republic od Korea, Seoul University Engineering Building (37° N, 126° E) b. W-SODIS c. SOCODIS d. W-SOCODIS e. I-SOCODIS Rain Water Tank SNU RRC 6th World Water Forum KSU RFA

14. The quality of rainwater samples Main target • Samples were always collected from the same outlet point, about 1.35 m from the base of the tank • The reason for the different initial values of all the parameters is the effect of the season and residential time in the tank • These are used as the standard initial values for the rainwater samples in this study. SNU RRC 6th World Water Forum KSU RFA

15. Weather conditions Weak Weather Moderate Weather Radiation Temperature Radiation Temperature • Weather is categorized into three different types, depending upon weak, moderate sunlight radiations. • The temperature difference is about 2~10 0C, with the great temperature rise in the SOCO-DIS & W-SOCO-DIS system. SNU RRC 6th World Water Forum KSU RFA

16. Results and Discussion

17. The effects of weather condition • In case of SODIS, No parameter met the potable guideline values • The difference of disinfection efficiency of SOCO-DIS & W- SOCO-DIS system is about 20-40% with that of simple SODIS mostly because of the enhanced effects of concentrated radiations and heat. Weak Weather Moderate Weather

18. The effects of initial pH • Rainwater using lemon and vinegar as catalysts(for acidic pH) offered best disinfection efficiency for SOCO-DIS system for all microbial parameters without any exception. • Overall disinfection efficiency increased from 10 to 20% by decreasing pH values from basic to neutral and then acidic states, respectively. SODIS SOCODIS

19. Conclusions

20. Conclusions • Disinfection efficiency of the W-SOCO-DIS or I-SOCO-DIS is 20~40 % better than SODIS and it managed complete disinfection under moderate weather condition • Developed SODIS system- SOCODIS : disinfection efficiency of SOCODIS system is better than SODIS about 20-40% because of the enhanced effects of concentrated radiations. - W-SOCODIS : The maximum temperature increase due to wrapping with plastic bags was about 4-7 C°, which enhanced the disinfection efficiency by about 5-8%.- I-SOCODIS : using lemon and vinegar as catalysts makes low pH improving the efficiency from 10 to 20 % SNU RRC 6th World Water Forum KSU RFA

21. Conclusions • this method can be easily applied to any place to gain acceptable water in the world, especially where the centralized water supply system is not affordable in a short time period, eventually contribute to achieve the MDGs. SNU RRC 6th World Water Forum KSU RFA

22. Thank you