Dictionary of Water and Waste Management, Second Edition

A: AAFEBR Azotobacter

AAFEBR acid mine drainage

AAFEBR

Anaerobic attached film expanded bed reactor, i.e. an expanded bed biofilm reactor operated anaerobically.

AAO process, A2O process

An adaptation of the A/O process . It is an activated sludge process that can achieve nitrification, denitrification and biological phosphorus removal as well as BOD removal. The three stage process involves an anaerobic zone of about one hour retention followed by an anoxic zone of similar size and finally an aerobic (oxidation) zone of 4 to 6 hours retention ( see Figure A.1). In the process the third zone is used for BOD removal and nitrification. The recycle from the end of the third (aerobic) zone back to the inlet of the second (anoxic) zone results in the nitrate being mixed with the wastewater in the anoxic zone and the nitrate is denitrified to nitrogen gas. The return activated sludge from the sedimentation tank is fed back to the start of the anaerobic zone. The first zone is required in order to obtain biological phosphorus removal. The percent removal can be in excess of 95% for nitrogen and 90% for phosphates.


Figure A.1: AAO process, flow diagram.

AAS

Atomic absorption spectrometer.

abattoir wastewater

See meat processing wastewater.

abiotic

Description of the non-living part of an ecosystem.

ablation

Removal. The opposite of accumulation.

A B process

A wastewater treatment process used in Europe that uses two acti vated sludge plants in series, i.e. aeration tank, sedimentation tank. Each sedimentation...

UNLIMITED FREE
ACCESS
TO THE WORLD'S BEST IDEAS

SUBMIT
Already a GlobalSpec user? Log in.

This is embarrasing...

An error occurred while processing the form. Please try again in a few minutes.

Customize Your GlobalSpec Experience

Category: Nitrification and Denitrification Systems
Finish!
Privacy Policy

This is embarrasing...

An error occurred while processing the form. Please try again in a few minutes.