Methods and compositions for removing perchlorate and/or nitrate from contaminated material utilizing a DM-17 bacteria. DM-17 is a gram-negative, motile, polymorphic, facultative anaerobe which is deposited with the American Type Culture Collection under ATCC No. PTA-2685. DM-17 may be used as a substitute for anaerobic bacteria which are presently being used in biological systems for removing perchlorate and/or nitrate from water and other contaminated materials, such as soil. Enhancement of nitrate reduction results from the presence of a level of perchlorate. Enhancement of perchlorate results from the presence of a level of nitrate. Particular carbon contributors further enhance remediation.