Study On Soil Washing Of Cadmium Contaminted Soil By Using Wine-processing Waste Sludge

Chemical remediation technology is one of the best ways to remove the heavy metal pollution of soil and reduce soil heavy metal contents. In this study, wine-processing waste sludge extract and pomegranate wine-processing waste sludge extract (extraction agents are potassium chloride solution, ammonium sulfate solution and ammonium acetate solution) as eluent, to time, pH, concentration and liquid-solid ratio as test conditions, single and multiple oscillations leaching test for restoration means to conduct the removal of soil cadmium pollution studies, the optimal conditions for screening and verification. In order to make waste sludge for cadmium contaminated soil waste site remediation work to provide a theoretical foundation and reliable basis. The main findings are as follows:(1) Under the same experimental conditions, the wine-processing waste sludge extract by potassium chloride waste (WWSK) for the removal of cadmium contaminated soil is best, followed by the wine-processing waste sludge extract by ammonium sulfate (WWSS), the worst is wine-processing waste sludge extract by ammonium acetate (WWSC), but the difference between the two better extract is small, therefore, potassium chloride and ammonium sulfate for use as wine-processing waste sludge extract leaching of cadmium contaminated soil extraction agent.WWSK optimized leaching of cadmium contaminated soil leaching conditions, time of 240 minutes, pH 4, wine waste concentration 15 g L-1,liquid soil ratio 15:1, the oscillation frequency of three times; WWSS of time 120 minutes. pH 2, wine waste concentration 60 g L-1, liquid soil ratio of 10:1, the oscillation frequency is four times; WWSC of time 360 minutes, pH 2. wine waste concentration 15 g L-1, liquid soil ratio 15: 1. the oscillation frequency of three times.(2) under the same experimental conditions, the three pomegranate wine-processing waste sludge extract effect of the removal of contaminated soil cadmium trend is pomegranate wine-processing waste sludge extract by potassium chloride (PWSSK)> pomegranate wine-processing waste sludge extract by ammonium sulfate (PWSSS)> pomegranate wine-processing waste sludge extract by ammonium acetate (PWSSC), but the difference between the two is small in front, so that potassium chloride and ammonium sulfate for use as pomegranate wine-processing waste sludge extract leaching of cadmium contaminated soil extraction agent.PWSSK optimized leaching of cadmium contaminated soil leaching conditions, time of 120 minutes, pH of 3, pomegranate wine waste concentration 60 g L-1, liquid soil ratio of 5:1, the oscillation frequency is four times; PWSSS of time 60 minutes, pH 2, pomegranate wine waste concentration 60 g L-1, liquid soil ratio of 10:1, the oscillation frequency is four times; PWSSC of time of 120 minutes, pH 2, pomegranate wine waste concentration 15 g L-1 soil liquid ratio of 20:1, the oscillation frequency of four times.(3) Under optimal conditions, the six combinations of Cd removal eluent improved significantly compared with the corresponding conventional conditions, an increase of 8.12%-558.1%, including an increase in the maximum WWSK and PWWSK. Compared with single shock under normal conditions of leaching, Cd removal WWSK and PWWSK increased 49.31%, respectively,145.89%; compared with the number of optimal leaching under normal conditions of shock, WWSK and Cd removal respectively PWWSK increase of 15.56%,8.12%. Therefore, the potassium chloride can well extract the dissolved organic matter from waste sludge extrac, and combination of liquid potassium chloride and dissolved organic matter in the waste form suitable eluent leaching of cadmium in the soil remediation.(4) the optimal conditions, after each waste sludge extract leaching of cadmium contaminated soil, reducing the whole cadmium, especially non-residual cadmium especially exchangeable cadmium, reducing the total exchangeable cadmium cadmium proportion the relative increase of the residual fraction of the total cadmium cadmium proportion of cadmium in soil residues play a role in curing to achieve the leaching of cadmium contaminated soil restoration purposes.