Treatment of Akkulam Dredged Material with Lime: Fid-Bau Portal

Treatment of Akkulam Dredged Material with Lime

Abhijith, A. / Jaya, V.

The Akkulam Lake is one of the oldest tourist spots in Trivandrum which has become a disposal site for biomedical and industrial wastes. The study hence emphasized on a pollution-free effective utilization of the dredged material, analysing the environmental risks with its remediation and stabilization. It initially involved determination of the heavy metals in the dredged material by X-ray fluorescence spectrometry and was found that its heavily polluted by nickel and lead and is moderately polluted by zinc as per US Environmental Protection Act standards. Remediation of the soil is done by stabilizing it with varying percentage of lime from 6 to 12%. The efficiency of the treatment is determined primarily through unconfined compressive strength test and column leachate test. The concentrations of heavy metal in the leachate were observed to be decreasing with time. The maximum immobilization was achieved for lime content 10 and 12% with an efficiency of 82% for lead and 67% for nickel, respectively. Moreover, the UCS values surpassed the disposal standards as well as the CBR value improved by 81.9%, which suggested possibility of reuse as subgrade fill in road pavements. WiscLEACH software was used to predict the concentration contours of leached metals upon reusing lime stabilized material, which proved that the remediation technique adopted not only improved the soil strength but also reduced the environment risk associated with the contaminated soil by avoiding any further leaching out of metals into the groundwater table and ecosystem.