UK HQ Your time

Industry Overview

Treating High-Strength Refinery Streams

Sour water and desalter effluent represent the most challenging refinery wastewater streams. Sour water from amine regeneration and sulphur recovery contains high concentrations of ammonia, hydrogen sulphide, and phenols. Desalter effluent brings high salinity, solids, and emulsified oil. Our integrated treatment approach combines steam stripping, oil separation, and specialised biological or chemical polishing to render these streams safe for discharge.

Steam Stripping

Sour water strippers (SWS) remove H2S and NH3 prior to advanced biological treatment, reducing toxicity and odour emissions.

Desalter Treatment

Specialised DAF and coalescing systems handle high-salinity desalter wastewater with emulsified oil.

Phenol Removal

Biological or chemical oxidation processes reduce phenol concentrations to <0.5 mg/L meeting strict discharge standards.

Reuse Integration

Treated desalter effluent can be recycled to crude desalting or cooling tower makeup reducing freshwater demand.

Applications

Sour Water & Desalter Sources

Amine Regeneration

Sour water from amine treating units containing H2S, CO2, and heat-stable salts requiring steam stripping.

Sulphur Recovery Units

Treatment of sour water from Claus plants and tail gas treating units with high sulphide and ammonia loads.

Crude Desalting

High-salinity wastewater from electrostatic desalters containing oil, solids, and dissolved salts.

Hydroprocessing Units

Sour condensate from hydrotreaters and hydrocrackers with ammonia, sulphides, and dissolved organics.

Coking Operations

High-phenol sour water from delayed coking and fluid coking with concentrated organics.

Crude Unit Overhead

Sour water from atmospheric and vacuum tower overhead systems containing chlorides and sulphides.

Treatment Process

Integrated Sour Water & Desalter Treatment

1

Equalization

Equalization tanks blend variable sour water streams and dampen concentration shocks.

2

Oil Separation

API separators and DAF remove free and emulsified oil from desalter and sour water.

3

Steam Stripping

Sour water strippers remove H2S and NH3 under pressure, producing stripped water suitable for advanced biological treatment.

4

Biological Treatment

MBBR or SBR systems remove residual phenols, organics, and reduce COD.

5

Final Polishing

Self-cleaning filters provide final suspended solids removal before discharge or reuse.

Recommended Equipment

Products for Sour Water & Desalter Treatment

DAF Flotation Systems

High-efficiency oil and solids removal for high-salinity desalter effluent and sour water.

Benefit: Salt-tolerant design

API Separators

Gravity oil-water separation for free oil removal from desalter wastewater.

Benefit: Low operating requirement

MBBR Systems

Moving bed biofilm reactors for high-rate COD and phenol removal in saline conditions.

Benefit: 90%+ COD removal

LAMELLA Clarifiers

High-rate solids separation for primary and tertiary clarification in minimal space.

Benefit: 70% smaller footprint

Sour Water Stripper

Custom-designed stripping columns for H2S and NH3 removal from refinery sour water.

Benefit: >99% sulphide removal

Self-Cleaning Filters

Automatic backwash filtration for final polishing and protection of downstream equipment.

Benefit: Continuous operation

Key Benefits

Why Choose Reynolds & Bauhm

Handle high salinity and sulphide concentrations
Remove ammonia to <10 mg/L discharge limits
Reduce phenol to <0.5 mg/L
Corrosion-resistant materials for sour service
Integrated stripper and advanced biological treatment
Enable desalter effluent recycling
Minimise H2S odour and safety risks
Custom designs for existing refinery infrastructure

Related Refinery Processes

Explore Other Refinery Treatment Steps

Refinery Overview

Comprehensive multi-stage treatment for petroleum refinery effluents.

Explore Oilgas Refinery

Oil Separation

API separators and DAF systems for refinery oil and grease removal.

Explore Oil Separation

Biological Treatment

MBBR and SBR systems for COD, phenol, and dissolved organics removal.

Explore Biological Treatment

Sludge Management

Dewatering and oil recovery from refinery sludge streams.

Explore Sludge Management

Water Reuse

Polishing systems for cooling tower makeup and boiler feed pre-treatment.

Explore Water Reuse

ATEX Compliance

Equipment engineered for explosive atmospheres with ATEX certification.

Explore ATEX

Related Pages

Chemical Atex

Chemical industry wastewater treatment for atex-certified equipment.

View Page

Global Standards Reference

Directory of international wastewater treatment regulations and equipment compliance standards Organised by country and region.

View Page

Oil Water Separation

Oil and gas wastewater treatment for oil-water separation systems.

View Page

Oilgas Atex

ATEX-certified wastewater treatment equipment for explosive atmospheres in oil, gas and petrochemical facilities.

View Page

Oilgas Downstream

Refinery wastewater treatment including API separators, DAF, advanced biological treatment and polishing for strict discharge.

View Page

Oilgas Drilling

Treat drilling muds, cuttings wash water and site runoff.

View Page

Refinery Sour Water — Design Parameters

Sour water collection, segregation and routing strategy at a refinery.

Sour Water Sources

Crude unit overhead; FCC fractionator overhead; hydrotreater stripper overhead; coker fractionator; sulphur recovery (Claus) tail-gas treater. Each has different H₂S / NH₃ ratio.

Characterisation

Typical untreated sour water: H₂S 500–5,000 ppm; NH₃ 500–5,000 ppm; phenols 10–200 ppm; cyanide 1–50 ppm; mercaptans 5–100 ppm.

Phenolic vs Non-Phenolic

Segregate phenolic streams (FCC, coker) from non-phenolic (crude, distillate hydrotreaters). Allows separate stripping conditions and protects ammonia recovery quality.

Hydrogen Cyanide

HCN co-produced in coker / FCC sour water. Reacts with Fe equipment to form ferrocyanide complexes that resist standard stripping. Pre-treat with NaOH + polysulphide.

Surge Tank & Buffering

Surge tank upstream of stripper provides 4–8 hours residence to absorb feed variability. Skim oil layer separately collected. Inert blanket prevents H₂S escape.

Closed System Design

All sour water piping fully gasketed/welded with vapour space tied to refinery vent or thermal oxidiser. No atmospheric exposure permitted under HSE H₂S regulations.

API Separators — Engineering Deep-Dive

Stokes’-law sizing, API Publication 421 design methodology, rectangular API / CPI / TPI configurations and refinery-train integration.

Need Sour Water Treatment Solutions?

Contact our experts to design a system for your refinery's most challenging wastewater streams.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.