N.Karthika et al. Int. Journal of Engineering Research and Applications www.ijera.com ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 2) January 2016, pp.13-18 www.ijera.com 13|Page Remediation of contaminated soil using soil washing-a review N.Karthika * , K.Jananee ** , V.Murugaiyan *** * Students, Department of Civil Engineering, Pondicherry Engineering College ** Students, Department of Civil Engineering, Pondicherry Engineering College *** Professor, Department of Civil Engineering, Pondicherry Engineering College ABSTRACT Pb, Zn, Ni, Cu, Mn and Cd are heavy metals occur naturally as trace elements in many soils. The present paper reviews the remediation of heavy metals of contaminated soil by soil washing using different agents. It was noted that the contact time, pH, concentration of extract ant and agitation speed were affected the process while remediation, so accordingly select the conditions to obtain efficiency which is mainly depend upon the type of soil, contaminationtype, contamination period and metals present in it.EDTA is effective when compared with other chelating agents for heavy metals especially for lead but it has low biodegradation. Because of the nature of low biodegradability, EDTA can be reusedfurther by membrane separation and electrochemical treatment, or degraded by advanced oxidation processes. Keywords -Chelating agents, EDTA,Extractants, Heavy metals, Soilcontamination, Soil washing. I. Introduction Nowadays, soil is becoming polluted due to some form of industrial activity, agricultural chemicals or the improper disposal of waste. The biggest concern associated with soil contamination is the harm that it can cause to human health and environment. To remediate a soil, there are a number of different methods currently employed in the process of dealing with soil contamination. Mainly, the goal of soil remediation is to restore the soil to its natural, pollution-free state. This study deals with soil washing using different extract ants. The advantage of soil washing method is the high extraction efficiency and the specificity for heavy metals. To achieve treatment costs low, the soil can be reused and it should be possible to recover and reuse the chelating agent for further extraction cycles, so that soil cleanup achieved.[1] Soil washing has the following merits. [2][3]  Reducing the volume of decontaminant soil , so thus reducing costs;  Physical separation allows simultaneous treatment of metal and organic pollutants;  Metals can be recovered and reused;  Treated soil can be redeposited on site;  Metals adsorbed to soil particles can be treated;  Generally removal of pollutant efficiency is between 60-90%;  Costs are relatively low. The main disadvantages of soil by washing are:  For the equipment, the need of a space big enough;  The need for wash water treatment;  The use of washing agents increase the cost of the process and may cause problems related to reuse of treated soil;  The technology is not suitable for soils with high clay content [2][3] II. Sources of contamination There are two types of contamination, namely: 2.1.Artificial contamination which is contamination made by artificially in order to get good homogeneity in terms of consistent heavy metals concentration and speciation, soil composition ,contamination process and contamination period. This would minimize ambiguity in the extraction results arising from sample heterogeneity. [4] 2.2 Naturally contaminated soil. The natural contamination of heavy metals was occurred due to many activities such as Fertilizers, Pesticides, Bio solids and Manures,Wastewater,Metal Mining and Milling Processes and Industrial Wastes and Air- Borne Sources .use of all these, can unknowingly occurs heavy metals such as Pb, Cd, Hg, Ni and Zn etc. ,, in the soil and cause effects on the environment. III. Soil washing using different extract ants Several types of chemical agents can be used to extract heavy metals for soil washing technology from contaminated soils. The extract ants may be acids, bases, chela- ting agents, electrolytes, oxidizing agents and surfactants [1][5][6][7], but the most popular extractive reagents are acids and chelating agents for heavy metals decontamination. RESEARCH ARTICLE OPEN ACCESS