Table 6.

Summary of Bioreactor studies for perchlorate treatment.

Type of system	Description	Concentration (μg/L)	Reference
Upflow fluidized bed reactor	Water contaminated with perchlorate, nitrate and chlorinated solvents. The system consists of bioreactor, an UV oxidation system, an air stripper and a disinfection system. The bioreactor uses ethanol as feed.	Influent: 2,500 Effluent from bioreactor: < 4	[75]
Fluidized bed reactor	System consists of four primary and four secondary FBRs, using sand and GAC as media.	Influent: 200,000 Effluent: < 18	[76]
Fluidized bed reactor	Water contaminated with perchlorate, metals and volatile organics. FBR is inoculated with pre-conditioned GAC containing biosolids acclimated to perchlorate removal. Acetic acid and inorganic nutrients are added. Excess biomass is removed from media.	Effluent: <4	[77]
Hall bioreactor	System consists of baker tank, deaeration reactor, methanol tank, and patented Hall reactor. Hall reactor contains floating media (poly- urethane based sponge) cut into one-centimeter cubes. Media provides support to bacterial colonies. Methanol fed as carbon source. Temperature ranges from 8 to 35 deg C.	Influent: 300 to 1000 Effluent: non-detectable limits	[86]
Upflow packed bed reactor	Use of a packed bed anaerobic bioreactor containing sand or plastic media. Acetic acid was constantly fed. Biological reactions initiated by bioaugmentation of the columns with perchlorate respiring bacterial strain Dechlorosoma sp.	Influent: 75 Effluent: < 4	[90]
Hollow fiber membrane bioreactor	The bioreactor consists of a bundle of hydrophobic hollow fiber membranes (polyurethane encased within microporous polyethylene) where hydrogen gas diffuses through and autotrophic biofilm is developed outside the membrane, where bacteria (dichloromonas sp. PCI) reduce perchlorate.	Influent: 55 Effluent: 2	[91]
Packed bed bioreactor	Laboratory scale treatment of groundwater contaminated with perchlorate and nitrate. The reactor was fed with a gas mixture of H2 and CO2 and inoculated with hydrogen oxidizing perchlorate degrading bacterium.	Influent: 75 Effluent: 25–30% reduction.	[89]
Packed bed bioreactor	A pure perchlorate respiring isolate (KJ) and mixed culture was used. Acetate required by mixed culture was observed to be twice more than that required by pure culture. Detention time observed to reduce using pure isolate.	Influent: 20 Effluent: < 4	[83]
Anaerobic treatment	Domesticated sludge was used. Acetate was fed as carbon source. Bacteria exposed to DO were incapable of reducing perchlorate. Addition of little Fe(0) accelerated while Fe(II) inhibited perchlorate removal.	Reduced to non-detectable limits.	[92]