Sustainable treatment of perchlorate contaminated water.

• Main Author: Faccini, Johanna
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/37677

Perchlorate is a stable and soluble substance that can last for decades in the environment. Studies have shown that it can reduce iodine uptake into the thyroid gland which is of concern for people with decreased iodine intake, pregnant women and small children. Perchlorate is removed from drinking water using highly selective ion exchange (IX) resins that are replaced after exhaustion and incinerated or disposed in a landfill since there are no viable methods for regenerating them. One of the major limitations in regeneration of these single use resins is achieving complete desorption of perchlorate. The sustainability of treatment processes for perchlorate contaminated water can be achieved by regenerating the exhausted resin. A study on the adsorption and desorption equilibrium, kinetics and biological regeneration of perchlorate from a trybutylamine strong base anion (SBA) exchange resin was conducted. Adsorption and desorption equilibrium could be described using the Freundlich model with estimated parameters KF = 50 (mg/g)(L/mg)1/n and n = 2.36. The calculated average perchlorate-chloride separation factor was 4700 ± 1700 and the resin capacity was 1.4 meq/mg. The kinetics of adsorption and desorption of perchlorate from the resin were found to be controlled by chemisorption since a pseudo-second order rate model fit the data the best. The results from the physical/chemical studies were then applied to model the biological regeneration of the resin using the culture NP30. Experiments conducted with the exhausted resin inside a membrane to avoid direct contact with the culture, demonstrated the biological regeneration of the resin by degradation of the desorbed perchlorate. The model was able to describe the desorption and biodegradation of perchlorate from the exhausted resin and the results were comparable to the experimental data. The model was found to be sensitive to the Freundlich adsorption intensity parameter n.