Destroy extreme COD (10,000-100,000 mg/L), toxic organics, and ammonia using high-temperature aqueous oxidation with air at 10-20 MPa and 200-320°C.
Wet Air Oxidation (WAO) is a thermal-chemical process that destroys organic compounds in aqueous solution using oxygen from compressed air at elevated temperature (200-320°C) and pressure (10-20 MPa). At these conditions, dissolved oxygen becomes a powerful oxidant that mineralizes organics to CO2 and water, and oxidises ammonia to nitrogen gas. WAO is used when advanced biological treatment is impossible due to toxicity, salinity, or extreme COD. It is more energy-efficient than incineration because water remains liquid, avoiding vaporisation energy.
Handles COD 10,000-100,000 mg/L that would overwhelm any biological process. 80-99% COD removal.
Destroys phenols, cyanides, pesticides, and pharmaceuticals that would inhibit advanced biological treatment.
Exothermic oxidation heat recovered via heat exchangers. Preheats influent, reducing external energy by 50-70%.
Unlike biological nitrification, WAO oxidises ammonia to N2 gas in the same reactor – no separate ammonia treatment.
Step-by-step breakdown of the treatment process from influent to effluent.
Wastewater preheated by heat exchange with hot reactor effluent. Fresh air compressed to reactor pressure and preheated separately.
Wastewater and compressed air enter bubble-column or tube reactor at 10-20 MPa, 200-320°C. Residence time 30-120 minutes.
Dissolved oxygen oxidises organics: CnHm + O2 → CO2 + H2O. Ammonia: NH3 + O2 → N2 + H2O. Phenols, dyes, and toxins fully destroyed.
Hot effluent passes through heat exchanger, transferring heat to incoming wastewater. Cooled effluent at 80-100°C exits.
Off-gas (CO2, N2, excess O2) separated in flash vessel. Optional CO2 capture. Liquid effluent proceeds to polishing or salt recovery.
Explore the equipment components that make this process effective.
High-pressure bubble-column reactor, SS316Ti clad, 10-20 MPa, heat recovery.
High-pressure compressor delivering air at reactor pressure, 100-500 Nm3/h.
Multi-stream heat recovery preheating influent and air with reactor effluent.
Gas-liquid separator with pressure let-down and CO2 capture option.
Destroy toxic organics from agrochemical, dye, and speciality chemical production.
Mineralise API residues and fermentation waste with high potency and variability.
Treat spent caustic and sulfidic wastewaters from refining operations.
Reduce COD 50,000 mg/L and ammonia 2,000 mg/L to discharge levels.
This treatment stage is engineered to achieve specific contaminant removal targets while providing stable, predictable performance across variable inlet conditions. Design parameters are calculated from wastewater characterisation data, regulatory requirements, and site-specific constraints including footprint, energy availability, and operator capability.
Design validated by CFD modelling and pilot testing to confirm performance guarantees.
Equipment selected for 20-year design life with minimal wearing parts and easy access.
Automated dosing and feedback control minimise reagent consumption and sludge production.
Online monitoring and data logging demonstrate continuous consent compliance.
| Design Flow | 10 – 5,000 m³/h (application specific) |
| Inlet Variability | Designed for 1:3 peak-to-average flow ratio |
| Removal Efficiency | 85 – 99% depending on target contaminant |
| Hydraulic Retention | Calculated from kinetic constants and safety factors |
| Power Consumption | 0.5 – 5.0 kWh/100 m³ (process dependent) |
| Chemical Dose | Auto-controlled based on online analysers |
| Sludge Production | 0.2 – 1.5 kg DS/kg contaminant removed |
| Materials | SS304, SS316L, or carbon steel with coating |
No treatment stage operates in isolation. This process is designed to receive conditioned influent from upstream stages and deliver effluent quality suitable for downstream processes. Hydraulic and organic loading rates are balanced across the complete treatment train to prevent bottlenecking and ensure overall plant efficiency. Our engineers model the complete flowsheet to optimise Capital expenditure and Operating expenditure across the plant lifecycle.
Screening, equalisation, and pre-treatment protect this stage from damage and overload.
Effluent quality ensures downstream biology, filtration, or disinfection performs optimally.
Reject streams, filtrate, and centrate are routed back to appropriate upstream points.
Our engineers design and commission complete treatment systems including all equipment, automation, and commissioning support.
Our expertise spans multiple industries with sector-specific water treatment solutions.