REMOVAL OF HEAVY METAL (LEAD) FROM WASTEWATER

Abstract

This dissertation presents an experimental investigation on removal of lead from wastewater using various methods, viz, reaction with H2S gas, adsorption with hydrated lime, silica gel and activated charcoal. The wastewater sample was synthetically prepared by dissolving a known amount of lead nitrate in distilled water. The effect of pH of the solution, contact time and dose of chemical used on percent lead removal has been • investigated for each case. Based upon the results of the above experiments, an experimental facility consisting of a packed bed of activated charcoal was set-up to study the continuous • adsorption of lead ions on activated charcoal particles. a result of the interpretation of the experimental data, it has been found that lead can be removed from wastewater sample using the above chemicals. But, the percent lead removal differs in each case, Lead has been fouled to be removed completely from the sample, when H2S gas was paSsed for a period of 60 seconds to the wastewater sample. However, it could not be regarded as one of the -promising method of treatment due to pollution hazards created by it. Hydrated lime, silica gel and activated charcoal removed lead ions from the sample, depending upon the contact . period, pH and the amount of chemical used. Analysis of the data obtained on the packed bed column of activated charcoal provided a correlation amongst the time at iii which .lead starts appearing in the solution,, bed depth and flow rate of the wastewater solution. The correlation can be used to determine the time of operation in continuous systems for the removal Of lead ions from wastewater by activated charcoal.