The BAC process consists of both activated carbon adsorption and biodegradation of organics by microorganisms. By combining adsorption and biodegradation, it results in partial regeneration of the activated carbon through biochemical activities, while the carbon bed is in operation. The less biodegradable organics are adsorbed on the carbon and then it is slowly degraded by microorganisms (Ng, 2008).
The major obstacle to operating reverse osmosis units at higher recoveries is the precipitation of sparingly soluble salts. Salt precipitation can be controlled by using an anti-scalant and by controlling the feed water pH. This will result in lower recoveries, which is undesirable (Kepke, n.d.).
