Study And Design Of The Water Supply Project In Kabala Area Of Mali

Water supply project in Kabala area, Bamako, Republic of Mali, is one of the representative projects which Chinese government gives Africa preferred loans. This project includes three parts: water intake project, water purification project and water transportation project.Scientific prediction was made on water requirement of Kabala area on the basis of investigation to the present situation of water supply in Bamako. At last make a decision that the total design scale is 24×104 m3/d, short-term (2012) scale is 14.4×104 m3/d and long-term (2020) scale is 9.6×104 m3/d.Lots of investigation and analyses on Niger water quantity and level assurance rate are made in this paper because the Niger is the only source of Kabala water plant. The site selection of water plant and the way of water withdrawal are also analyzed and discussed in this paper. Finally we confirm the water withdrawal position where guarantee high insurance rate of water quantity and good water quality.Water purification plant can provide the process that has high safety of water quality and fit Mali production-management level, namely the process of tubing static mixer + small grid reaction + inclined plate precipitation with small spacing +"V"filter. Use chemical oxidations pretreatment method to control the content of organics effectively and add PVC to solve sudden water pollution problems.Water transportation project is designed according to the short-term scale of 14.4×104 m3/d, including a length of 10 km DN1200 clean water aqueduct from purification plant to Baco Djikoroni and a reservoir which has 10000m3 effective volume. Through the calculation and analysis of water hammer and comparison of all kinds of pipes, at last we choose nodular iron pipe as the major material and use steel pipe in complicated and passing obstacles area .The capacity of short-term water supply in Bamako increase 14.4×104 m3/d after completion of this project, which ensure the water quality and improve the safety of water supply. The total investment for the short-term project is 7592.64 million dollars, year water volume is 5256×104 m3, average water cost is 0.427 dollars/ m3.