คุณภาพน้ำจากระบบการเก็บกักน้ำฝนจากหลังคาในตำบลถ้ำใหญ่ อำเภอทุ่งสง จังหวัดนครศรีธรรมราช WATER QUALITY OF ROOF RAINWATER HARVESTING SYSTEM IN THAMYAI, THUNG SONG DISTRICT, NAKHON SI THAMMARAT

Abstract

This study involved analyses of roof rainwater harvesting systems at a rural housing society in Tambon Tumyai, Thung Song, Nakhon Si Thammarat, where locate near many industry plants. A total of 40 samples were collected from roofed rainwater tanks and analyzed for turbidity, color, pH, total dissolved solids, sulfate and coliforms on October, 2013. Additional information, including the domestic sanitation practice of people was examined. Analysis of harvested rainwater sample from residential roofs indicated that the measured pH and sulfate generally matched the Department of Health guideline of drinking water B.E. 2010. On the other hand, all water samples have positive for coliform bacteria, which is an important bacteriological parameter. Turbidity and color above the limit levels 17.5 and 5 percentage, respectively. The collected rainwater is contaminated by several factors include; the clean of rooftop catchment area and gutter and the sanitation practice of people. It was found that 67.5% of household do not use first flush diverters, 65% of household do not clean inside rainwater tank, 47.5% of household use rainwater storage tank with no lid. This result shows the poor quality of stored rainwater in rainwater tank of roof rainwater harvesting system. Therefore, it is necessary to promote safe sanitation practice and raise public awareness to addressing growing threats to drinking water quality.