Environmental Discharge Standards have tightened up with emphasis on reducing the chemical usage in effluent treatments.
Some 77 billion bbl of Effluent/produced water is being produced annually and this will increase as oilfields mature.
Over the last 10years effluent [produced water] discharged into the environment is becoming an issue and management of produced water presents challenges and costs to oil companies or operators.


Produced water is water trapped in underground formations that is brought to surface along with oil or gas. It is by far the largest volume by-products or waste stream associated with oil and gas production.

Oil and Grease are the constituents of produced water that receive the most attention in both onshore and offshore operations.

Salt content (expressed as salinity, conductivity, or TDS) is a primary constituent of concern in “Onshore and/or Environmental Sensitive” operations.

Organic and Inorganic compounds. These vary greatly from location to location and even over time in the same well.

Metals found in produced waters include zinc, lead, manganese, iron and barium.


DOWTEC developed the DECORE+POREFLON technology for oil & gas market that separates oil-water system that delivers a high water quality of less than 5ppm (DECORE) for discharge and less than 1ppm (POREFLON) for Re-injection & with Reverse Osmosis process to provide feed water specification for industrial application.

Water Samples and type of recovered oil taken the actual field operation from the DECORE+POREFLON process.
Stage 1
Removing O&G to levels for downstream treatment
Stage 2
Further reducing O&G to levels for disposal or re-injection and EOR applications
Stage 3
Further treat O&G for reuse as organic free salinity water or to stage 4
Stage 4
Remove dissolved pollutants for porta-water usage
Added when required for certain uses
/ Flocculation
POREFLON Microfiltration Granular Activated carbon Reverse osmosis Ion exchange
[ess than 5ppm]
[less than 1ppm]
EOR Application
  Drinking / Boiler Feed  
  DECORE Technology Other Oil Water Saperation Technology
  • Wide array of applications from Chemical, marine, Oil and Gas, Petrochemical to industrial waste-water, Pharmaceutical, Pulp and Paper.
  • Treatment process are limited to the Oil and Gas industry.
Associated Equipment
  • One single stage treatment to reduce oil to less than 5 mg/1
  • Current treatment system use a combination of up to 3 stage of treatment process such a CPI, IGF or DAF, Nut shell filter to reduce to less than 5 mg/1
Chemical Inventory
  • No chemical handling and the associated hazards and safety issues. Oil removal efficiency up to 99%
  • Chemical required for pH conditioning and associated treatment cost is reduced.
  • Chemical handling required and also associated hazards and safety issues.
  • Other systems can only achieve to up to 75% removal.
  • Chemical such as Coagulants and flocculants, pH
Residual Waste
  • High Water % volume is separeted using the DECORE process
  • High yield residual Oil is recovered
  • Separate Emulsion Treatment Process using chemicals to separate the water % volume from the sludge.
  • System is mounted on skids or containerised, hence easily transportable to other sites
  • Smaller footprint
  • Permanent installation making it difficult to transport to another site if required
  • Much bigger footprint
  • Easy to operate as no chemicals are used in the actual process.
  • Chemical system requires more operators to maintain and operate.
  • Capacity can be easily increased by adding additional trains that is aligned with the production demands
  • Phased Expenditure based on demands rather than committing to high UPFRONT CAPITAL EXPENDITURE.
  • Fixed and not easy to increase the capicity
  • UPFRONT "Sunken Cost"

Technical Details - DOWTEC DECORE® (5 ppm) & POREFLON® (1 ppm) Oil in Water Treatment



ECF is the electrochemical techniques which has interactions with Coagulation and Flotation processes

There are three main mechanisms in the whole of ECF process:

-Electrode oxidation
-Gas bubble generation
-Flotation & sedimentation of flocs formed

A simple ECF reactor is made of an electrolytic cell with pairs of electrodes (Anodes, cathodes) which are commonly known as "sacrificial electrodes" and made of conductive metal plates.

An electric current is applied to sacrificial electrodes to generate coagulating agent species and gas bubbles to destabilize suspended, emulsified, or dissolved contaminants in an aqueous medium and from flocs to be removed by flotation and se dimentation.
Principles and Technologies Size of particle that needed to be removed, pm Oil conc. in treated eff., ppm
Coalescene -PPI/CPI 40 40 < 10
Air /gas flotation -Dissolved Air Flotation
-Induced Air Flotation
3-5 (w/t flocculant)
25 (w/o flocculant)
< 15
< 15
Centrifugal force -Hydrocyclone
< 100
< 10
Electro Coagulation / Flocculation -DECORE Unlimited smallest-Up to 2mm < 5


The electro-flotation clearly shows advantages over either DAF, settling or impeller flotation

Parameters Treatment Methods
  EF DAF IF Settling
Bubble Size pm 1-30 50-100 0.5-2 -
Specific Electricity Consumption W/m3 30-50 50-60 100-150 50-100
Air Consumption m3/m3 water - 0.02-0.06 1 -
Chemical Conditioning   inorganic


+ flocculants
Treatment time min 10-20 30-40 30-40 100-120
Sludge volume % of treated water 0.05-0.1 0.3-0.4 3-5 7-10
Oil removal efficiency % 99-99.5 85-95 60-80 50-70
Suspended solids removal efficiency % 99-99.5 90-95 85-90 90-95
Source: Handbook Advanced Physicochemical Treatment, Lawrence K. Wang
  • MF: removing contaminants from fluids by passing the fluids through a micro-porous membrane
  • POREFLON is especially suitable for micro-filtering fats, oils and greases contaminated fluids with the 0.45 pm pore size membrane is preferably made of polytetrafluoroethylene (PTFE)

  • PTFE:
    - Chemical and heat resistant properties give a wide variety of cleaning options
    - High tensile strength gives the membrane filter a longer life span.
    - Able to sustain high flow rates when fluids

3D Layout Drawings

The 2009 Singapore International Water Week - our presence:
Our sincere and heart-felt thanks to all who visited our booth, share with our their experiences, their needs. We are indeed much honored to be able to share with all present, our products, services and technologies.
To all our clients, existing or potential, we trust that you have gained better insight of our field of specialty after your visit, we hope to see you again in next year exhibition

DOWTEC is continuously looking at ways of improving the clients’ profit margins by introducing better effluent treatment processes that deliver high yield - quality water for the purpose of discharging to the environment as well as for Water Flooding and Enhanced Oil Recovery Projects.
With most of existing oilfields entering the mature phase, oil companies are opting for secondary injection or tertiary EOR projects to extend life of the oilfields which translate to better Ultimate Recovery.
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