10:45 〜 12:15
[AHW19-P08] ASSESSMENT OF GROUNDWATER QUALITY AT A FORMER LANDFILL SITE
キーワード：Landfill, Groundwater, Contamination , Water quality , Monitoring well
Re-development of an abandoned and closed landfill site is essential to provide new land for development. This paper highlights the groundwater quality assessment at a proposed re-development project of a former landfill site in Malaysia. The main objectives of the study are to assess the groundwater quality and to determine the presence of any potential contaminants. A total of 33 boreholes were constructed comprising of 18 deep boreholes and 15 shallow boreholes. The maximum depth of Deep Borehole (DBH) was 80 m for Shallow Boreholes (SBH) was 25 m. The geology of the site is consisting of limestone. The borehole data (% RQD) suggested that the limestone is classified as a good aquifer with high fracture density. A total of thirty (30) groundwater samples were collected and chemically analysed. A Piper plot indicates that most of the groundwater samples represent CaHCO3 type of water. Some samples fall in the field of mixed Ca-SO4. Very few samples represent mixed CaNaHCO3 facies. The groundwater quality results indicated that the concentrations of certain groundwater parameters or elements in groundwater exceeded the Environmental Standards. BOD, COD, ammonia, boron, manganese, iron, arsenic, magnesium, sodium, Total coliform and Total E. Coli exceeded the Environmental Standards. The groundwater study concludes that the groundwater quality was already contaminated by leachate produced from the abandoned landfill. There is a potential threat from this contaminated water to human health and the environment. Several options shall be selected to minimize the impact to groundwater such as (i) limit the infiltration of water through the landfill cover by providing impermeable clay cover and (ii) extract the leachate / polluted groundwater from the landfill and treat the groundwater according to Environmental Standards.