## Permeate
### FO-MFC Integration  
Osmotic MFCs (OsMFCs) are a result of the integration of the MFC with the FO membrane [42]. This setup has also been examined in numerous research studies. Forward osmosis membranes were employed in the MFC to eliminate salt while simultaneously achieving COD subtraction and generation of bioelectricity [18]. The design of the setup included both internal and external placements of the membrane. When the membrane is placed internally, it is either installed between the electrodes as a separator or submerged in the anode/cathode compartment as a purification unit used to divide the draw and feed solutions [43]. The water passes from the anode to the cathode compartment via the FO membrane because of the osmotic pressure gradient, which leads to the dilution of saltwater. In the externally placed setup, the MFC and the membrane unit can work independently. Several studies were conducted by mounting the forward osmosis membrane as an interior segregator to examine the internal configuration of the setup [44]. The external arrangement of the OsMFCs was used for the conversion of the organic constituents in the influent-polluted water to alcohol and short-chain fatty acids, which were restricted by the forward osmosis membrane [30]. This further elevated the alkalinity and conductivity of the solution, thereby enhancing the ion transfer and generation of power in the MFC. The membrane fouling of the forward osmosis membrane was also decreased by pretreating the wastewater with the MFCs [45]. Another experiment reported that the power production of such a system was 43 W/m\({}^{3}\), which was greater than both AEM and CEM, which had an energy output of 40 W/m\({}^{3}\) and 23 W/m\({}^{3}\), respectively. Despite having most of the acetate removed with an efficiency of 90% in the OsMFC, some of the acetate leaked into the cathode chamber through the membrane. Another study also obtained the same results but with an additional benefit in the form of desalination. Improved proton shuttling from the anode chamber to the cathode chamber by the FO membrane was achieved in the OsMFC [46]. This helped in improving the production of electricity in the integrated OsMFCs as compared with the stand-alone MFCs operated in either mode, batch (NaCl solution) or continuous (seawater). Unfortunately, when a lower concentration of contaminated water was employed, the high values of power generation were not reached, with the highest power density attained being only 4.38 W/m\({}^{3}\) after a time-consuming procedure lasting 40 days. The decontamination potential of organic matter and phosphorus reached 97%, but owing to the lower elimination of the forward osmosis membrane, the elimination capability of nitrogen was hindered [23]. There was significant amplification of the power density of the MFC due to the studies conducted on the solute buildup, improved buffer capacity, and conductivity. The amplification achieved was an increase from 3 to 11.5 W/m\({}^{3}\) in power density [45]. The membrane fouling was also alleviated as the MFC acclimatized and lowered the generation of sludge. There were remarkable removal efficiencies recorded with the employment of thin-film composites (TFC) in the OsMFC, with organic removal being 95% and phosphorus removal being 99%. The COD of the effluent was also quite low (less than 20 mg/L). In another study, an MFC was integrated with anaerobic forward osmosis membrane bioreactors for the generation of biogas and methane and the simultaneous elimination of pollutants such as phosphorus and chemical oxygen demand. Using a SnO\({}_{2}\) nanoparticle electrocatalytic cathode in an electrocatalytic-assisted MEC, undesired carbon dioxide produced from biogas was converted to formate, with the maximum faradic yield of formate being 85% at 1.2 V. In comparison with AnOMBR, when AnOMBR-MEC was employed, the concentration of methane increased from 55% to 90% at the end of the operation, and the production of methane increased by 1.6 times.