Oil in Water Treatment
From free oil to ppb — complete de-oiling of process water
What this application solves
Oil appears in water as free, dispersed and emulsified fractions, each needing a different separation mechanism. WFS designs staged de-oiling that removes the easy free oil first and then progressively tackles dispersed and emulsified oil down to very low residuals for discharge or reuse.
The train scales from simple gravity separators for bulk oil to membrane systems achieving single-digit ppm or ppb oil-in-water for reuse and reinjection duties.
Typical influent characteristics
| Parameter | Typical range |
|---|---|
| Oil & Grease (in) | 100 – 10,000 mg/L |
| Free oil | majority |
| Emulsified oil | variable mg/L |
| TSS | 50 – 1,000 mg/L |
| Flow | 5 – 1,000 m³/h |
These ranges frame the design basis. WFS confirms the exact values for your site through laboratory characterization and 24-hour composite sampling, capturing variability across normal, upset and turnaround operation before any equipment is sized.
The problems — and how WFS solves them
- Stable surfactant-bound emulsions
- Wide droplet-size distribution
- Solids that stabilize emulsions & foul media
- Very low oil-in-water targets for reuse/reinjection
- Variable, shock oil loads
- API / CPI gravity separation for free oil
- Coalescing media for dispersed oil
- Coagulation + dissolved/induced gas flotation
- Walnut-shell / media filtration
- Ultrafiltration for emulsified-oil polishing
Targets the system is designed to meet
| Performance parameter | Design target |
|---|---|
| Oil & Grease (out) | < 5 – 10 mg/L |
| UF polishing | < 1 (ppm) |
| TSS | < 10 mg/L |
| Reuse-grade | to spec |
Guaranteed, tested performance
Every WFS system is commissioned against a documented performance test. We design to the discharge consent, reuse specification or zero-liquid-discharge target — and verify it on site before handover, then sustain it through O&M.
Filtration approach & system required
Separation follows droplet size: gravity for large free-oil droplets, coalescence and flotation for dispersed oil, and membranes for tight emulsions. De-emulsification chemistry is added where surfactants stabilize the oil.
Solids removal is integrated throughout because solids both carry oil and foul the de-oiling media and membranes.
- API / corrugated plate interceptor separators
- Coalescer packages
- Dissolved / induced gas flotation units
- Walnut-shell / multimedia filters
- Ultrafiltration skids
Modular process-train schematic
- 1Gravity SeparationAPI / CPI separator
Remove bulk free oil & solids
- 2CoalescenceCoalescing media pack
Merge dispersed oil droplets
- 3FlotationDAF / IGF + coagulation
Float emulsified oil & fines
- 4Media FiltrationWalnut-shell / multimedia
Remove residual oil & SS
- 5Membrane PolishingUltrafiltration
Reach ppm/ppb oil-in-water
Indicative system specification
Layout & general arrangement
Gravity separation sits at the inlet sump; flotation and filtration follow in a compact line; UF polishing is skid-mounted at the outlet. Recovered oil is routed to slop; floated sludge goes to dewatering.
The arrangement allows bypass and staged operation so the plant can run at partial trains during maintenance.
- 01Gravity Separation
- 02Coalescence
- 03Flotation
- 04Media Filtration
- 05Membrane Polishing
What WFS delivers
- 1Oil-in-water characterization (free/dispersed/emulsified)
- 2Staged de-oiling design & target spec
- 3Equipment fabrication & supply
- 4Installation, recovered-oil & sludge routing
- 5Automation, commissioning & performance test
- 6Reuse / discharge compliance verification
- 7O&M & media/membrane management
From study to continuous O&M
- 01Study & Assess
- 02Characterize Water
- 03Custom Design
- 04Pilot & Trial
- 05Detailed Engineering
- 06Equipment Design
- 07Fabricate
- 08Deliver to Site
- 09Construct
- 10Electrical & Automation
- 11Continuous O&M
Discuss your oil in water treatment project
Share your stream data and target specification — WFS will characterize the water and propose a custom train.