Introduction to the Successful Application of Biological Treatment Technologies

A/O Process (Anoxic/Oxic Activated Sludge Process)
Process Overview
The A/O process includes an anoxic zone and an aerobic zone, using microorganisms for nitrogen removal and organic degradation.
Key Steps:
Wastewater enters the anoxic tank for denitrification;
Then flows into the aerobic tank for organic removal
and nitrification;
Effluent is clarified in a settling tank.
Application Features:
·Simultaneous removal of COD, BOD, and ammonia;
·Simple structure, stable operation;
·Widely used for municipal and industrial wastewater with nitrogen concerns.

Contact Oxidation Process
Process Overview
Contact oxidation uses biofilm on media surfaces to degrade pollutants in wastewater.
Key Steps:
Wastewater enters the contact tank and interacts with biofilm media;
Aeration provides oxygen for microbial activity;
Effluent is settled before discharge or further treatment.
Application Features:
·Compact footprint, resistant to load shocks;
·Fast start-up, high effluent quality;
·Ideal for decentralized systems like hotels, schools, hospitals.

Biological Aerated Filter (BAF)
Process Overview
Biological Aerated Filters (BAF) combine aeration, biodegradation, and filtration in one compact system.
Key Steps:
Water and air are introduced from the bottom of the filter;
Biofilms on media degrade pollutants;
Filtration and solid-liquid separation occur simultaneously.
Application Features:
·Small footprint, highly integrated;
·Produces high-quality effluent, suitable for reuse;
·High automation, ideal for urban water polishing.

Membrane Bioreactor (MBR)
Process Overview
Biological Aerated Filters (BAF) combine aeration, biodegradation, and filtration in one compact system.
Key Steps:
Water and air are introduced from the bottom of the filter;
Biofilms on media degrade pollutants;
Filtration and solid-liquid separation occur simultaneously.
Application Features:
·Small footprint, highly integrated;
·Produces high-quality effluent, suitable for reuse;
·High automation, ideal for urban water polishing.

Constructed Wetland Process
Process Overview
Constructed wetlands simulate natural systems using plants, microbes, and substrates to purify wastewater.
Key Steps:
Pretreated wastewater flows into the wetland;
Roots and substrate absorb and degrade contaminants;
Treated water exits for reuse or discharge.
Application Features:
·Eco-friendly, low maintenance;
·Low operating cost with aesthetic value;
·Best for rural or nature-integrated projects.