Using ground scrap tires to remove o-xylene from groundwater
Barbara I. Crouthamel · 1994
Searching for a method to use scrap tires in an environmentally friendly and economically feasible manner has been merged with looking for an economically viable method for extraction of toxic organics from groundwater, as an alternate to activated carbon adsorption and airstripping. Specifically, the work presented in this thesis investigates the viability of using crumb rubber in a fixed bed sorption process to remove o-xylene from groundwater. Batch equilibrium tests were conducted using rubber particulates obtained from two different sources. The adsorption isotherms that were generated from these tests were used along with several isotherms obtained from the literature in order to investigate the effects of equilibration time, particle size and surface treatment with reactive gases on the sorption capability of crumb rubber. In addition, batch equilibrium tests were conducted on granulated activated carbon in order to determine the cost effectiveness of crumb rubber as an alternate to activated carbon in groundwater treatment. Based on adsorption capacity, activated carbon was determined to be approximately 3 to 7 times as cost effective as crumb rubber without taking into account recharging and disposal costs ofthe sorbent. Dynamic column tests were performed on one type of crumb rubber. One of the five tests conducted reached breakthrough, enabling the computation of the sorption capacity at saturation. This value was in good agreement with the predicted value from the batch isotherms. The computed sorption capacity at breakthrough was a smaller percentage of the I equilibrium capacity than expected. Factors such as channeling, high concentration, and short contact time in the column test are attributed as the cause ofthis difference. Based on the the findings of this thesis, crumb rubber may be a viable and feasible source of sorbent to remove or control the migration of volatile organic compounds, such as xylene in contaminated groundwater.