Abstract:
This research aimed to evaluate the lifetime, preliminary health risks, and the economic valuation assessment of the groundwater filter system installed in Ban Mai Nai Fun Village, Sanian Sub-district, Mueang Nan District, Nan Province. From the study, treated groundwater can pass the water quality standards for groundwater consumption. The evaluation of the preliminary health risks illustrated that the calculated Hazard Quotient (HQ) of fluoride ion decreased to lower than the acceptable standard.The lifetime evaluation of the fluoride removal system and dissolved organic carbon by column system found that at the height of the filter layer at 25 cm and the filtration rate of 2.30 ml/min can perform the highest fluoride and dissolved organic carbon removal with the longest breakthrough time and lowest usage rate. Moreover, the lifetime of the filter media in the column evaluated by the Thomas equation also reported the most effective condition and highest adsorption capacities at the column height of 25.00 cm and the filter rate of 2.30 mL/min. In addition, the Bohart and Adam equation for fluoride removal concluded the relationship followed the equation Y= 429X - 6.430, where Y is the breakthrough time (minutes), and X is the height of the bone char filter layer (cm.) while the removal of dissolved organic carbon followed equation Y = 50,931X934, where Y is the breakthrough time (minutes), and X is the activated carbon filter height (cm.) by the filtration rate at 0.01 cubic meters/hour. From the economic valuation assessment of the project, it is found that the investment from the government delivered to the villagers presents the value of the net return (NPV) at 6,448.36 baht, the benefit-cost ratio (B/C Ratio) at 1.008, the internal rate of return (IRR) at 4.407%, and the payback period (PB) 0 years. However, the investment and operating by the villagers themselves showed the value of the net return at -365,822.50 baht, the benefit-cost ratio at 0.6909%, the internal rate of return and the payback period could not be calculated.