Tiếng Việt
中文 (中国)
Oil-contaminated wastewater is not just a number above the limit on an analysis report. It means the risk of a suspension order, heavy administrative fines, and erosion of the brand reputation your business has worked hard to build. Did you know that mineral oil can persist in the environment for up to 50 years, becoming a lasting “legacy” of pollution?
At NGO International, we do not just see the numbers. We see through to the complex nature of the problem and the “pain points” of the business. With nearly 10 years of experience, we deliver a superior technical solution, a solid “shield” that helps you turn an environmental challenge into a lasting competitive advantage.
1. Why oil-contaminated wastewater is hard to treat
Oil-contaminated wastewater is not simply the oil film you can see on the surface. It arises from many essential activities such as: cleaning storage tanks at fuel depots, draining tank bottoms, washing workshops, cooling water from mechanical engineering plants, and rainwater running off oil-contaminated areas.Technically, oil in wastewater exists in 3 complex states, each requiring a different solution:
- Free oil: Large oil droplets that float to the surface and form a visible oil film. This is the easiest form to treat, but it makes up only part of the total oil.
- Emulsified oil: This is the real “enemy”. Under the effect of detergents, industrial chemicals or mechanical pressure, oil is broken into ultra-fine droplets (micron size) that stay suspended in the water. Ordinary gravity separation methods are completely ineffective against this form.
- Dissolved oil: Oil molecules (such as aromatic compounds) dissolve completely in the water, are colourless, cannot be separated mechanically, and are the main cause of the characteristic odour that remains after treatment.
Single-method treatments on the market often fail because they address only one of the three states, leaving effluent with fine oil films, high turbidity and a characteristic odour.
2. Main sources of oil-contaminated wastewater
- Water from periodic cleaning of storage tanks at fuel depots to ensure fuel quality.
- Tank bottom water drained after a tanker has finished discharging into the depot’s storage tanks.
- Industrial cleaning water, both periodic and after repairs of process equipment in fuel depots.
- Rainwater falling on yard areas at depots and filling stations that may be contaminated with oil.
- Yard cleaning water, vehicle washing and vehicle maintenance water.
- Cooling water or wastewater from mechanical engineering plants
3. Current treatment options for oil-contaminated wastewater and NGO’s solution
After a period of research, NGO can provide an oil-contaminated wastewater treatment solution that removes mineral oil thoroughly by chemical adsorption, at a treatment cost far lower than using adsorbent materials, with a fast reaction time. Mineral oil is almost completely removed, the treated water has no oil odour, and the solution suits small discharge points as well as projects with large discharge volumes.
Table: Comparison of 3 common treatment solutions vs NGO’s solution
| Method | Operating Principle | Advantages | Critical Disadvantages | Optimal Scope of Application |
|---|---|---|---|---|
| Coagulation – flotation (traditional) | Uses chemicals (alum, PAC) to gather oil droplets into large flocs, then uses air bubbles to push them to the surface. |
|
| Suitable as a preliminary treatment step to reduce the load on the main system. Not effective on its own. |
| Membrane filtration (MF, UF) | Uses pressure to push water through a membrane with ultra-fine pores, retaining the oil molecules. |
|
| Used as a final “polishing” step for reuse purposes. Not economical for treating raw wastewater. |
| Adsorption with materials | Uses materials with a large surface area (activated carbon, oil-absorbent cloth) to “soak up” and hold the oil molecules. |
|
| Should only be used as the final polishing stage, when most of the oil and sediment has already been removed. |
| Multi-stage chemical adsorption (NGO International solution) | Uses a specialised adsorbent compound combined with a chemical reaction to break down, encapsulate and thoroughly remove oil molecules (including emulsified & dissolved forms). |
|
| A comprehensive, optimal solution for all types of oil-contaminated wastewater, especially when high effluent quality and reasonable operating costs are required. |
4. Featured project
- Challenge: A large oil port depot was under pressure from the regulator because wastewater from its old treatment system still contained an oil film and a strong odour, and its total oil content exceeded the national technical regulation limit on wastewater by 10 times.
- NGO International’s solution: We redesigned the entire physico-chemical section, replacing the old flotation tank with a high-efficiency flotation system.
- Results: Within just 2 months of implementation, oil and grease content fell by 99%, and the effluent was clear, odour-free and consistently met Column B. The business saved 30% of its monthly chemical costs thanks to the automatic dosing system.
“NGO International’s system is truly different. They do not just install equipment; they have a deep understanding of the nature of oil-contaminated wastewater. We now feel completely confident whenever an inspection team visits, and we also save a considerable amount in operating costs.”– Mr T.M.H, Operations Director
5. Frequently asked questions
Definitely. Our process includes a dedicated chemical “demulsification” stage before coagulation, designed to treat even the most stubborn emulsified oil effectively.
We prioritise highly automated solutions that minimise human intervention. NGO International will thoroughly train your team and transfer the technology until they can operate it proficiently.
Yes. By thoroughly treating all 3 forms of oil (free, emulsified and dissolved), especially the odour-causing aromatic compounds at the final stage, the effluent will be clear and free of the characteristic odour.
The initial investment cost depends on the scale and the level of pollution. However, thanks to optimised operation, our solution significantly reduces chemical, electricity and labour costs in the long term, delivering higher economic efficiency.
Oily sludge is hazardous waste. We will design a safe storage area and advise on, and connect you with, licensed units that collect, transport and treat sludge in accordance with the regulations of the Ministry of Agriculture and Environment.
See more : https://ngoenvironment.com/en/solution.html
For advice on solutions for oil-contaminated wastewater treatment contact us on +84 24 7300 0890 or email office@8ngo.com
Talk to an NGO engineer
Free survey and consultation. Send us your wastewater type (industrial or domestic), flow rate (m³/day), influent analysis results if available and required effluent quality; an NGO engineer will propose a suitable technology and a realistic quotation.
Offices in Hanoi and Ho Chi Minh City · +84 24 7300 0890 · office@8ngo.com
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