text: The reductive processes discussed above can be enhanced in two ways. One is by increasing the amount of usable iron in the subsurface to increase the rate of the reduction by chemical or biological means. The second method is to enhance the reducing ability of the iron by coupling it with other chemical reductants or using biological reduction with it. Using this processes, scientists combined sodium dithionite with iron to treat Chrominum VI and TCE effectively.
  Combining bacterial action and biological processes with iron is also known to be effective. The most evident uses of biological processes are with the EZVI technology created by NASA and with the EHC product created by Adventus. Both of these materials have iron within some biological matrix (iron is suspended in vegetable oil in EZVI and in organic carbon in EHC) and use microbial organisms to enhance the reduction zone and to create a more anaerobic environment for the reactions to take place in.