Anaerobic water purification systems for aerobic COD removal - Water and Wastewater
In an aerobic treatment system, air is injected which is used by aerobic bacteria to convert BOD to carbon dioxide and water.
Organic components + O2 are converted to H2O + CO2 + BIOMASS
Primary treatment for solids removal and anaerobic treatment are usually followed by aerobic treatment.
The activated sludge system consists of an aeration stage - and an anoxic/oxic compartment if nitrogen has to be removed - and secondary sedimentation with sludge return. Options are first quality surface aeration, fine bubble aeration and jet aeration.
After secondary clarification, further treatment can consist of filtration, de-nitrification (for achieving very low nitrogen concentrations) or effluent softening. For nitrogen removal at higher concentrations and filtration, see ANAMMOX® and ASTRASAND®.
When treated water will be reused or if water will pass through a sewer, flash aeration is often required. The main reason is odour control, but it will also remove some additional COD, especially when the aeration tank is followed by solids removal such as DAF (Dissolved Air Flotation).