Treating Oily Wastewater: Key Challenges and Effective Treatment Solutions

Oily wastewater poses a significant challenge for industrial operations. When oils and fats enter wastewater streams, they can cause pipe blockages, damage treatment equipment, and lead to costly compliance issues with environmental regulations. This article dives into proven treatment methods that help protect your infrastructure, meet discharge standards, and reduce operational costs..

What Makes Oily Wastewater So Challenging?

Managing oily wastewater presents a range of operational difficulties. Oils and fats quickly interfere with treatment processes by forming stubborn layers on equipment surfaces. This buildup reduces treatment efficiency and increases the frequency and cost of maintenance. Without the right treatment strategy, these issues can escalate rapidly.

Common problems faced by facilities include: 

• Equipment fouling and clogging
• Reduced treatment efficiency
• Increased maintenance and downtime
• Higher chemical consumption
  
  

As operational costs rise, facilities often struggle to maintain regulatory compliance. Traditional treatment methods frequently rely on heavy chemical use, which drives up expenses and increases discharge fees charged by municipal authorities. Additionally, inconsistent treatment outcomes create uncertainty, raising the risk of violations.

Beyond immediate operational concerns, many plants find their existing treatment approaches far from optimal. This inefficiency leads to a domino effect of higher chemical costs, increased fees, and more frequent maintenance. Recognising these challenges is crucial for moving toward smarter, more effective solutions.

Effective Treatment Approaches for Oily Wastewater

A strategic, multi-faceted approach is essential for treating oily wastewater efficiently. Understanding the available options allows facilities to design a treatment system that is both effective and cost-efficient.

Chemical Treatment

Modern chemical treatments form the backbone of oily wastewater management. Advanced coagulants and polymers break down emulsified oils and suspended solids, simplifying their removal from water. Key chemical strategies include:

• Innovative plant-based coagulants for acidic (low pH) conditions
• Advanced water-based polymer solutions for efficient separation
• Specialised chemical programmes tailored  for high-fat content
  
  

Physical Separation Techniques

Physical separation technologies work alongside chemical treatment to remove separated oils and solids. Dissolved Air Flotation (DAF) systems are particularly effective, using micro-bubbles to float separated oils to the surface for removal. This approach:

• Handles high volumes efficiently
• Reduces sludge management costs
• Improves overall treatment reliability
• Maintains consistent flow rates
  
  

The key to success lies in selecting the right combination of treatments for your specific wastewater profile. Factors such as oil content, pH levels, and flow rates all influence the optimal solution design.

Implementing an Effective Oily Wastewater Treatment System

Successful oily wastewater treatment starts with thoughtful system design and ongoing performance monitoring. Whether upgrading existing setups or installing new ones, several factors must be considered to ensure success and cost control.

System design begins with evaluating wastewater volume, oil levels, available space, discharge regulations, and budget constraints. These considerations guide the selection of technologies and capacity needed for a reliable and efficient treatment solution.

Once operational, continuous monitoring is key to maintaining performance. Regular water quality tests provide feedback on treatment effectiveness, while careful chemical dosing keeps processes optimised. Routine equipment maintenance prevents costly downtime, and compliance monitoring safeguards against regulatory issues. These proactive steps help keep operations running smoothly and costs manageable.

Real-World Success: Case Study with AAK Foods

These principles were recently demonstrated at AAK Foods' Runcorn facility, a leading producer of mustards, condiments, sauces, and dressings since 1971. Like many food manufacturers, their wastewater treatment challenges centred around managing oils and fats in their effluent stream. Previously, the company had been operating its effluent water treatment service on a month-to-month basis. As a result, the costs associated with the service fluctuated, and it was not performing at an optimum level.

Brian Jones, Business Development Manager at Veolia Water Technologies, explains: “The customer was happy with their previous effluent water treatment system but hadn’t realised it could be operating more efficiently. Upon meeting with us, it was discovered that the existing approach was unnecessarily costly. We used our expertise to evaluate what water treatment chemicals were best to use. This has helped the customer to reduce the amount of water treatment chemicals they require. In turn, this means less money had to be paid to the municipal waste water authority to have the excess water treatment chemicals removed.”

After reviewing the chemical composition of the water, our team of experts supplied a number of our water treatment chemicals. We supplied the client with our Hydrex 6861 plant-based coagulant and our Hydrex 6903 water-based polymer. The Hydrex 6861 chemistry was particularly well-suited to the effluent profile at AAK Foods because of its low pH level and because of the small capacity of the wastewater treatment plant.

A further advantage of our solutions is that they helped improve the site’s sludge management. In turn, this helped the dissolved air flotation unit to operate at a higher flow rate. Similarly, the client was able to save more money as they no longer needed to purchase expensive polymer dilution equipment, as the Hydrex 6903 water-based polymer is diluted through an inline dilution unit. Overall, the solution has allowed the effluent treatment plant to operate in a more steady and reliable manner.

As water treatment chemical dose rates at the site are now more controlled, usage is more predictable. As such, the site is able to achieve more uniform results, allowing plant engineers to reduce the time they spend checking that the water is within consent limits, which is required to avoid MOGDEN charges. This means that a key challenge associated with managing the effluent water treatment process has been eliminated.

Speaking on the project, Neil Heselwood, Engineering Manager at AAK Food Supplies, commented: “Veolia Water Technologies presented us with an honest and upfront approach to problem-solving, which helped us to achieve good results and reduce costs. To begin with, we wanted to trial the new system on a monthly basis. We were really impressed with the results and have now specified the new process for a further year. We’re also in constant communication with the Veolia team, and they continue to help us operate as efficiently as possible.”

To ensure that the results remain stable after its installation, our team maintains regular contact with the wastewater treatment plant. The team has already met with the plant for its first follow-up meeting and will review the use of water treatment chemicals in the process every four to five months. This helps to ensure that the right levels of water treatment chemicals are being used in the process. We will continue this process, carrying on the partnership model, which has helped make the installation such a success thus far.

To learn more about our water treatment solutions, please click here orcontact one of our experts today.