TABLE 2.
Different reactor configurations used to treat FPW and dominant microbial groups observed.
| Type of reactor | Reactor volume | Type of wastewater treated | TDS (mg/L) | Avg. COD removal (%) | Inoculum source | Dominant microbes in the reactor | Molecular method used | References |
| AGS-SBR | Lab-scale: 3.6 L, H/D – 10 | Synthetic FFB | 12,500–50,000 | 79 (TOC) | Aeration tank of hypersaline WWTP | Cellvibrionaceae, Rhodocyclaceae, Rhodobacteraceae, Phyllobacteriaceae | 16S rRNA amplicon sequencing | Zhang et al., 2018a |
| AS | NA | Real PW (China) | 5,500–16,000 | 72 | AS from oilfield bioreactor | Pseudoalteromonas, Marinomonas, Flavobacterium, Novosphingobium | PCR-DGGE | Wang et al., 2015 |
| MBR | Lab-scale: 5.1 L | Real PW (Turkey) | 9,200–24,900 | 70 | Lab-scale MBR treating PW | Azoarcus sp., Thauera sp., Rhodobacteraceae, Porphyrobacter sp. | PCR-DGGE | Kose Mutlu et al., 2018 |
| MBR | Lab-scale: 5 L | Synthetic PW | 64,400 | 83 | Enriched halophilic consortia | Marinobacter spp., Halomonas spp., Psychroflexus halocasei, Idiomarina loihiensis | Isolate 16S rRNA sequencing | Abdollahzadeh et al., 2013 |
| MM | 6-well plates | Synthetic media and real PW (PA, United States) | PW(A): 182,700; PW(B): 18,400 | NA | 10% (v/v) PW + AS from municipal WWTP | PW (A1/2): Halomonas, Idiomarina, Marinobacter Marinobacterium; PW (B): Rhodospirillaceae, Vibrio, Flavobacterium | Metagenomics + 16S rRNA amplicon sequencing | Akyon et al., 2015 |
| BAF | Lab-scale: D- 5 cm, H-76 cm | Real PW and FFB (CO, United States) | 10,460–18,170 | 80 | GAC from WTP | Aerated BAF: Flavobacteria, Gammaproteobacteria; Non-aerated BAF: Anaerolineae, Clostridia, Deltaproteobacteria | 16S rRNA amplicon sequencing | Freedman et al., 2017 |
| MFC | 100 mL | Synthetic and real FFB (China) | 19,000 | 72 | Anaerobic digestor, mature MFC effluent | Anode-Desulfuromonadales, Anolyte- Propionibacteriaceae, Sulfurovum, Rhodocyclaceae, Prolixibacteriaceae | 16S rRNA amplicon sequencing | Zhang et al., 2018b |
| MFC | 125 mL | Synthetic and real PW (Iran) | 65,000 | 95 | Hypersaline anaerobic pond | Desulfobacterales, Burkholderiales, Methylobacter, Methylotenera | 16S rRNA amplicon sequencing | Roustazadeh et al., 2017 |
AGS, Aerobic Granular Sludge; SBR, Sequencing Batch Reactor; AS, Activated Sludge; MBR, Membrane Bioreactor; MM, Microbial Mats; BAF, Biologically Active Filter; MFC, Microbial Fuel Cells; PW, Produced water; FFB, Fracturing Flowback; H/D, Height to diameter ratio; NA, Not available; TDS, Total Dissolved Solids; COD, Chemical Oxygen Demand; TOC, Total Organic Carbon; GAC, Granular Activated Carbon; WWTP, Wastewater Treatment Plant; WTP, Water Treatment Plant; PCR-DGGE, Polymerase Chain Reaction Denaturing Gradient Gel Electrophoresis.