Method and apparatus for nutrient removal with carbon addition

A wastewater treatment apparatus comprising:

• a biological nitrogen removal reactor, having a volume or a series of volumes, equipped for dosing electron donor or organic substrate in one or more zones, thereby maximizing the reduction of nitrate to nitrite for a first reaction and to supply nitrite as an electron acceptor for a second reaction under controlled addition of electron donor or organic substrate, the conditions being controlled either along the flow path or along the process timeline, and wherein the apparatus is integrated into a larger series of zones that include a multi-zone moving bed bioreactor or multi-zone filter system, membrane biofilm reactor, membrane bioreactor or suspended growth reactor, or a hybrid combination thereof, in series including:
• a a first zone including a denitratation and anammox reaction zones in which the electron donor addition is controlled to achieve a nitrate residual of approximately 1.5 mg/L or higher, followed by
• b an optional second denitrification zone in which optional additional electron donor is added to achieve full denitrification and low nitrate concentration, and/or
• c a final optional post aerobic zone removing residual ammonium, only if needed based on an ammonia treatment objective, is added after the first or second zone.

An apparatus where multiple biofilms are grown to maintain differential solids retention times to support different organism groups including mostly heterotrophic denitratation organisms and anammox organisms, or a combination thereof, wherein:

• a) the anammox or autotrophic organisms are grown within mostly sheltered biofilms including within granules, on or within media that include expanded clay, ceramics, lava rock, iron rich material, plastic or activated carbon;
• and where the anammox organisms are sheltered from backwash, air scour or shear;
• or, anammox organisms are selectively retained using screens, cyclones, air lift reactors, gravimetric devices, or flotation devices;
• and
• b) heterotrophic organisms are mostly grown on flocs or on surfaces or media including sand, anthracite, clay or plastic;
• and where the other heterotrophic organisms are subject to backwash, air scour or shear and to control the absolute or relative solids retention time.