Dissolved air flotation system and methods for biological nutrient removal

摘要

A wastewater treatment system including a contact tank, a dissolved air flotation unit, a fermentation unit, and a biological treatment unit is disclosed. A method of retrofitting a wastewater treatment system by arranging the wastewater treatment system such that floated biosolids are fermented in an anerobic environment and fluidly connecting the biological treatment unit to receive at least a portion of the fermented solids is also disclosed. The method optionally includes providing a fermentation unit and fluidly connecting the fermentation unit to a biological treatment unit. A method of treating wastewater including combining the wastewater with activated sludge, floating biosolids from the activated wastewater, fermenting the floated biosolids, and biologically treating the effluent with the fermented solids is also disclosed. A method of facilitating delivery of soluble organic carbon to a biological treatment unit is also disclosed.