Case Study • Aerospace NDT Wastewater
6 m³/day Fluorescent Penetrant Inspection Wastewater Treatment
Combined pretreatment, low-temperature vacuum evaporation, activated carbon and membrane polishing for difficult emulsified organic wastewater.
Design capacity
Influent CODcr
Reported treated-water CODcr
Reported liquid-waste volume reduction
Customer Challenge
The customer supplies fluorescent penetrant inspection lines for aerospace and defence manufacturing. Parts-washing wastewater contained fluorescent dyes, mineral oil, emulsifiers, surfactants and other organic additives. The stream showed high colour, stable emulsification, poor biodegradability and variable batch discharge.
Reported influent data included CODcr 6,954 mg/L, BOD₅ 1,978 mg/L and ammonia nitrogen 86 mg/L.
GRELLIX Process Solution
- Pretreatment: equalization, emulsion breaking and fine filtration to remove free oil, suspended solids and part of the colloidal load.
- Low-temperature vacuum evaporation: phase separation under vacuum, retaining dyes, oils and surfactants in a smaller concentrate stream.
- Activated-carbon polishing: removal of residual colour and dissolved organic compounds from the distillate.
- Membrane polishing: final barrier selected for the project’s local sewer-discharge requirements, with provision for future water-reuse upgrading.
Reported Operating Results
| Parameter | Influent | Treated Water |
|---|---|---|
| CODcr | 6,954 mg/L | 24.8 mg/L |
| BOD₅ | 1,978 mg/L | 7.5 mg/L |
| Ammonia nitrogen | 86 mg/L | 15 mg/L |
| Suspended solids | Not reported | 6.5 mg/L |
| Colour | High / emulsified | 5 times |
These figures are reported for this specific project and treatment train. They are not a general performance guarantee. Results for another wastewater stream depend on its composition, operating conditions and required local standard.
Customer Value
- More than 90% reported liquid-waste volume reduction.
- Smaller concentrate quantity requiring regulated disposal.
- PLC automatic control adapted to intermittent wastewater production.
- Modular polishing approach with future water-reuse upgrade potential.
Have a Similar Emulsified or High-COD Wastewater Stream?
Send a representative analysis and daily volume. Volatile organics, oil, surfactants and foaming behaviour must be evaluated before selecting an evaporator.