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

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

Introduction

Background < Tailand > < Uganda > 6th World Water Forum 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” 6th World Water Forum SNU RRC KSU RFA

What is rainwater harvesting system? Drinking Cleaning 1- I think, “only non-potable purposes” can be deleted because purpose of SODIS and related is to treat it for potable purposes. 2- Instead of Sewage pipe it could be drain pipe. Emergency Gardening 6th World Water Forum SNU RRC KSU RFA

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 supply safe drinking water by rainwater 6th World Water Forum SNU RRC KSU RFA

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 UV Infrared Reflection and Back-Radiation DO/pH Temp. Used PET bottle Attenuation By Plastic? Pasteurization Cellular Breakdown Conduction 6th World Water Forum SNU RRC KSU RFA

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

Limitation of SODIS 6th World Water Forum 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 6th World Water Forum SNU RRC KSU RFA

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 6th World Water Forum SNU RRC KSU RFA

Materials and Methods

Sample collection site Completion date 2005.10 Roof area 3,892 ㎡ Green roof area 935 ㎡ residence about 1,000 persons RWH Beginning date 2006. 4 A kind of catchment concrete, terrace, green roof Catchment area 3,652㎡ Tank volume 250 ton Consumed 60~90 ton/day Uses toilet * RWH : Rainwater harvesting system 6th World Water Forum SNU RRC KSU RFA

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

The quality of rainwater samples PHYSIOCHEMICAL PARAMETERS MICROBIAL PARAMETERS Initial Temp. 0C pH EC μS/cm DO mg/l Turbidity NTU TC CFU/100ml E-Coli 23-25 7-9 150-500 5-9 1-5 880-1100 200-250 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. 6th World Water Forum SNU RRC KSU RFA

Weather conditions 6th World Water Forum 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. 6th World Water Forum SNU RRC KSU RFA

Results and Discussion

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

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

Conclusions

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 % 6th World Water Forum SNU RRC KSU RFA

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. 6th World Water Forum SNU RRC KSU RFA

Thank you