Assessment and treatment of groundwater in Selangor area: unconfined and confined aquifer

A variety of chemical, physical and biological processes can alter the chemistry of water as it is moves along flow paths from recharge areas to points deeper in the aquifer. For industrial water use, these metals tend to oxidize and precipitate in piping systems reducing their hydraulic capacities. The aeration and filtration process is normally applied in treatment process for removing iron and manganese either for domestic consumption or irrigation purposes. The objectives of this paper are i) to investigate the groundwater properties refer to the type of aquifer, and ii) to analyze the groundwater properties during aeration process in a small tanks. Samples were collected from four different sites; two sites for each type of aquifer. Those samples will be treated by aeration (water-into-air method) and filtration process by using a small scale tank in laboratory with a final polish by using manganese greensand. The properties of groundwater such as pH, dissolved oxygen, turbidity and heavy metal concentration (iron and manganese) will be assessed during the process (3, 5 and 7 hours) and compared between two types of aquifer; unconfined and confined. The pH values for all samples after treatment process is in the range of 7.04 to 8.38 and 6.82 to 7.63 for unconfined aquifer (sample A, B) and confined aquifer (sample C, D) water samples, respectively. The water-into-air aeration methods increased the dissolved oxygen content for both aquifers. It can be summarised that the turbidity values for unconfined and confined aquifer samples are reduced which is for sample A; from 39.20 to 29.30 NTU, sample B; 27.40 to 19.09 NTU, sample C; 5.73 to 4.25 NTU and sample D; 9.17 to 6.32 NTU for the whole 7 hours process. For iron and manganese concentration, there are reduction pattern for all samples except for samples D, the values of iron concentration were not detected. It can be concluded that for all parameters observed, there are changes in values either increased or decreased throughout the aeration and filtration process for both studied aquifers