Dr. Paul Hatzinger is a Senior Scientist with Shaw Environmental.  He holds a PhD in Environmental Toxicology from Cornell University. Dr. Hatzinger's primary research interests concern the biodegradation and
bioremediation of emerging water pollutants, including perchlorate, NDMA, and nitramine explosives.

Presentation Description
Biodegradation and Bioremediation of N-Nitrosodimethylamine (NDMA)
N-Nitrosodimethylamine (NDMA) is a potent carcinogen and an emerging groundwater and drinking water contaminant that requires treatment to low ng/L concentrations. The objective of this SERDP-funded research project was to study NDMA biodegradation and to evaluate potential in situ and ex situ bioremediation strategies for this contaminant. Initial experiments revealed that propanotrophs and specific toluene-oxidizing strains were capable of cometabolizing NDMA, but that these organisms utilized completely different catabolic pathways. A laboratory-scale membrane bioreactor (MBR) was inoculated with the propanotroph Rhodococcus ruber ENV425 and fed propane as a primary substrate. At influent NDMA concentrations ranging from 10 - 100 ug/L, effluent levels of NDMA from the MBR were generally below10 ng/L for 5 months of operation. The potential for in situ treatment of NDMA was also examined using aquifer samples from several locations around the US. When aquifer samples were pre-incubated with propane and oxygen, native propanotrophs were able to reduce NDMA concentrations from ug/L to ng/L concentrations. No reductions in NDMA were observed in samples treated with oxygen only or in killed controls. The results from this research provide a basis for the further development of in situ and ex situ biological approaches for NDMA treatment.