Cost effective biological/chemical treatment of ammonia/ammonium impacted media

Treatability studies were performed to investigate inexpensive treatment methods for ammonia/ammonium-impacted soil and groundwater at two sites. The first site contained two areas of varying ammonia/ammonium levels in soil with low pH (<4). At this site, high ammonia levels varied from 140 mg/kg to 3,500 mg/kg. The effects of pH control and microbial stimulation by amendment with a carbon source and an inoculum (activated sludge) were evaluated to determine methods for effectively reducing ammonia levels. The second site contained ammonia-impacted groundwater. Site soil and groundwater samples were subjected to testing to evaluate the effectiveness of amendment (carbon substrates) addition and oxygenation on the reduction of groundwater ammonia concentrations in situ. Nitrogen pathway analyses were performed during both studies to verify that nitrification or other nitrogen transformations were not taking place and simply converting ammonium to a more mobile form. The results of these treatability studies identified easily implemented, cost-effective methods to reach environmentally acceptable end points and are presently being incorporated into full-scale remediation systems.