Remediation of Heavy Metals Contaminated Farmland and Fertility Enhancement
Date Issued
2007
Date
2007
Author(s)
Chang, Po-Wen
Abstract
There are millions of tons of hazardous wastes generated every year in the world. Due to improper waste handling techniques causing hazardous waste release in the past, thousands of sites were contaminated by heavy metals, organics and other hazardous materials, which posed an enormous impact on quality of groundwater, soil, and the associated ecosystems. During past decades, several new, innovative solutions for efficient removal of contaminants from soil have been studied to help correct environmental pollution. Despite numerous promising laboratory experiments conducted, there are still not many techniques successfully implemented on in situ soil treatment. Therefore, results from this in situ pilot-scale testing can be used to establish useful data for field-scale implementation in the future.lectrokinetic treatment process is of a useful remedial technology, particularly on the soil with low permeability. The purposes of this pilot test is to implements electrokinetic technology to remove heavy metals Cd, Pb, and Cr from the silty loam in the rice field, to evaluate the removal efficiency of Cd, Pb, and Cr, and to promote soil fertility enhancement during treatment process. The test used citric acid-surfactant mixtures as treatment solution under an implied electrical field to enhance the removal of Cd, Pb, and Cr and fertility of the silty farm soil simultaneously.he test soil of this pilot test was stockpiled into two cells, Cell A and Cell B, and both with dimensions of 3 m long, 3 m wide, and 0.5 m high. This test used citric acid as the main reactive agent and a biodegradable liquid surfactant as the metal chelating agent in both Cell A and Cell B. Additional food grade surfactant was added in Cell B. The test was conducted over a period of 92 days. The test results revealed that electrokinectic process in Cell A gained an average removal efficiency of 76.59%, 62.25% and 50.40% for Cd, Pb and Cr, respectively. Electrokinectic process in Cell B gained an average removal efficiency of 69.74%, 58.02% and 58.68% for Cd, Pb and Cr, respectively. According to the test results, Eelectrokinetic process is proven as a successful technology to remove heavy metals from contaminated soil. In addition, the content of total nitrogen, Bray-1 phosphorus, and exchangeable potassium and magnesium, were relatively elevated after 92 days of treatment duration. It concludes that electrokinectic treatment technology is capable of mitigating soil contaminated with not only heavy metals but also organic compounds, and thus is a potential in situ treatment technology in the future.
Subjects
Pilot test
Electrokinetic
Heavy metals
Treatment
Soil fertility
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-D89622006-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):4a4f68e52669b0140a4591d6cb79b525