Abnormal Operation And Economic Analysis Of Water-impreving And Defluoridation Projects In The Northern Rural Areas

Water-improvement and defluoridation is the basic control strategy presently in drinking-water type fluorosis areas. There are many fluorine reduction methods such as drilling deep wells, water diversion and removing fluoride by physical and chemical ways and so on. A certain number of projects are found scrapped or water fluoride concentration over-standard in investigations on the state and effect evaluation of water-improving and defluoridation projects. The adverse consequence is that residents in drinking-water type fluorosis areas keep drinking high fluoride water and facing the risk of fluorosis. Therefore, there is a lot of practical significance to analyze the abnormal causes and economic effects of water-improving and defluoridation projects.ObjectivesTo analyze the causes of water fluoride concentration over-standard projects and scrapped ones. To know the construction cost and recurrent cost of water-improving and defluoridation projects and make some economic analysis about them.MethodsA certain number of water fluoride concentration over-standard projects and scrapped projects were selected from identified water supply project areas using stratified random sampling method. To obtain the required information using accessing to historical data and site surveys. To analyze causes of abnormal water-improving and defluoridation projects. To describe the cost and usage situation of water-improving and defluoridation projects and do some economic evaluation.Results 4.1The main reasons for water fluoride concentration over-standard projects were the ruptured sidewall and the aging of defluoridation facilities, taking the proportion of51.28%and41.03%. The secondary reasons were imperfect management and the lack of defluoridation pharmacy, taking the proportion of5.13%and2.56%.4.2The main reasons for scrapped water-improving and defluoridation projects were using over life and the ruptured wall, taking the proportion of50.00%and25.00%. The secondary reasons were the poor quality and shortage of drinking water, taking the proportion of12.50%and12.50%.4.3The average number that water fluoride concentration over-standard projects kept providing low-fluoride drinking water was16.86±7.94years and the average life expectancy of scrapped water-improving and defluoridation projects was15.76±5.01years, both exceeding15years which was the design life of these projects.4.4The average construction cost for18water fluoride concentration over-standard projects was211.10±65.00thousand yuan, and the average recurrent cost was17.40±14.50thousand yuan per year. The average construction cost for8scrapped water-improving and defluoridation projects was141.90±36.90thousand yuan and the average recurrent cost was9.8±4.5thousand yuan per year.4.5Most villages improved water again and only few ones changed the equipment when projects were found water fluoride concentration over-standard. There was no significant difference in the construction cost, the recurrent cost, the average annual total cost and the per capita annual cost in between.4.6Most villages chose building single-village projects and only few villages chose building united-village ones. The construction cost, the recurrent cost and the average annual total cost of single-village projects were less than the ones of united-village projects. However, there was no significant difference in the per capita annual cost in between.4.7The years of actual service benefits for8scrapped water-improving and defluoridation projects was18.07million yuan year and the years of expected service benefits was17.03million yuan year, with the ratio of106.12%.Conclusions5.1The main reasons for water fluoride concentration over-standard projects are the leakage of pipeline network and the aging of defluoridation facilities.5.2The main reasons for scrapped water-improving and defluoridation projects are using over life and the ruptured wall.5.3There is no significant difference between improving water again and changing the equipment.5.4There is no significant difference in the per capita annual cost between building single-village projects and building united-village ones.5.5Water-improvement and defluoridation plays a positive role in promoting local economic development.