Strategies for Controlling Filamentous Bulking in Activated Sludge Wastewater Treatment Plants: The Old and the New

Filamentous bulking and foaming are the most common settling problems experienced in activated sludge (AS) wastewater treatment plants (WWTPs). The quality of final effluent is poor during episodes foaming, which an environmental, human health economic burden. Remedial measures often ineffective, traditional non-specific methods such as chlorination may also negatively impact important functional bacterial species nitrifiers. Modifications to older well new strategies required for controlling filamentous bulking. Laboratory testing needs be followed by at scale WWTPs. This review describes bacteria responsible bulking, with a focus on their global distribution known factors selective growth specific filaments. Traditional biological control reviewed discussed. Research gaps identified aim promoting continued efforts establish effective