Removal of Nitrate/atrazine Contamination with Zero-valent Iron-promoted Processes

This research project is designed to study the feasibility of removing or remediating nitrate/atrazine in groundwater using iron powder treatment. Iron powder was selected because it is cheap and nontoxic. Three different types of iron powders were used in this research. They were lab grade iron powder (about 0.02 micron in size), industrial grade iron powder (about 0.5 micron in size), and rusted industrial grade iron powder (about 0.5 micron in size). In the batch studies conducted, best nitrate removal was obtained using rusted iron powder (nearly 70% removal at approximately neutral pH). However, more atrazine was removed when lab grade iron powder was used (about 75% removal). During the column studies, it was found mixing two parts of fine sand with one part of iron powder prevented plugging and improved removal efficiency. More than 98% of the atrazine were removed by lab grade iron powder with less than two days detention time. On the other hand, nitrate removals were dependent on pH. High nitrate removals were observed at low and high pHs while less than 50% removals were observed near neutral pH.