Oil & Gas Water Treatment Systems

Pegasis* Multi-Stage Treatment System

Our patented Pegasis* technology is a multi-stage treatment system specifically designed to remove high levels of insoluble and soluble hydrocarbons, including BTEX, with very low OPEX and waste generation. The number of stages and technology used are chosen to best meet your water treatment criteria. If required, an optional biological treatment stage is included as a final polishing step before effluent disposal.
 

The Pegasis system can include the following stages 

1. Deoiling – deoiler hydrocyclones remove insoluble (free) hydrocarbons
2. Gas Stripping – a counter-current gas stripping column is used to remove the bulk of the soluble, volatile hydrocarbons (e.g. BTEX) 
3. Polishing – a regenerable or non-regenerable adsorbent removes soluble hydrocarbons to very low levels 
4. Biological treatment – specialised biomass degrades soluble, non-volatile organics (e.g. MEG, methanol) to CO2, water and additional biomass. A range of biological treatments are available to meet your COD, BOD and TOC effluent targets. 
    

Removing Solids and Contaminants from Process Streams

Filtration Systems

We offer a wide range of regenerable and non-regenerable filtration systems for removing solids and contaminants from your process streams. We will design a system to specifically target the removal, and recovery where required, of contaminants from your system to the particle size and contaminant concentration you require. Our range of filtration systems include: 

• Filter/coalescer units 
• Activated carbon filters 
• Cartridge filters 
• Nut shell filters 

We can design filtration systems for various organic and inorganic contaminants such as: 

• Sand 
• Oils and grease 
• Salts 
• Scaling compounds 
• Sulphur compounds 
• Mercury compounds 
• Metal oxides and other compounds

Corrugated Plate Interceptor (CPI) Units 

Water from oil and gas production facilities often requires a number of stages to effectively remove free oil and solids. Therefore, we offer a range of Corrugated Plate Interceptor (CPI) Units, which are particularly suited to slug and/or intermittent flow and can be designed for either live or degassed process fluids. 

Our CPI Units are designed to remove free oil and suspended solids from water as a primary stage of water treatment and utilize plate packs as the main separation device. The plate packs are designed with specific spacing and alignment to allow solids to settle and fall to the bottom while simultaneously allowing oil drops to rise and coalesce, thereby reducing the oil and solids loading from the downstream water treatment train and smoothing out flow slugging.  

Benefits  

• Low operating and maintenance cost 
• Proven robust and reliable design 
• Pressurized or non-pressurized design 
• Automated controls for unmanned operation

Electrostatic & Mechanical Treaters

After primary oil/water separation, there is often a small amount of unwanted salts in residual water in the crude oil that needs to be reduced to a concentration around 5-10 PTB (Pounds per Thousand Barrels) salt.  

This salt needs to be removed so that the crude oil can be processed in a refinery or stabilizer plant without fouling heaters and exchangers and other equipment. Crude Oil Desalting technology is used to remove residual salt to meet these requirements. The type and size of the Desalter that is used is dependent on a number of fundamental factors such as pressure, temperature, fluid viscosity and flow-rate, as well as customer requirements relating to maximum salt allowed in the product oil stream.  

Available Technologies

Veolia has developed a range of crude oil dewatering and desalting technologies to be applied in appropriate situations

• Free Water Knock Outs: Effective bulk water removal using horizontal vessels & mechanical coalescing packs to reduce water levels down to 2 - 5% BS&W (Basic Sediment & Water).  

• Heater Treaters: Dehydration at elevated temperature using gas or oil-fired burners and mechanical (to 0.5% BS&W) or electrical (to 0.2% BS&W) coalescing.  

• Dehydrators: Dehydration and associated salt removal using high voltage electrical grids to achieve 0.1 – 0.2% BS&W.  

• Electrostatic Desalters: Dilution water used to reduce salt content to 5-10 PTB.