How to Treat Oily Wastewater

Oily wastewater presents a serious challenge for industrial facilities. When oils and fats enter wastewater streams, they can clog pipes, damage treatment equipment, and create costly compliance issues with environmental regulations. This article explores effective treatment methods for managing oily wastewater, helping you protect your equipment, meet discharge requirements, and optimise operational costs.

What are the Specific Challenges with Oily Wastewater?

Oily wastewater creates significant operational challenges across industrial facilities. When oils and fats enter wastewater systems, they immediately begin impacting treatment efficiency. These contaminants form layers on equipment surfaces, reducing effectiveness and increasing maintenance requirements. Without proper treatment, the consequences quickly multiply.

The most common challenges facilities face include:

• Equipment coating and clogging
• Reduced treatment efficiency
• Higher maintenance requirements
• Increased chemical consumption
  
  

Operational costs often spiral as facilities struggle to maintain compliance. Traditional treatment approaches frequently rely on excessive chemical usage, leading to unnecessary expenses and higher discharge fees from municipal authorities. Moreover, inconsistent treatment results create uncertainty around compliance, putting facilities at risk of violations.

The impact extends beyond immediate operational issues. Many facilities discover that their existing treatment methods, while functional, are far from optimal. This inefficiency creates a cascade of problems: increased chemical costs, higher discharge fees, and more frequent maintenance requirements. Understanding these challenges is the first step toward implementing more effective solutions

How is Oily Wastewater Treated?

Treating oily wastewater effectively requires a strategic approach, often combining multiple treatment methods. Understanding the available solutions helps facilities choose the most efficient and cost-effective treatment strategy for their specific challenges.

Chemical Treatment Solutions

Modern chemical treatment forms the foundation of successful oily wastewater management. The latest coagulants and polymers work by breaking down emulsified oils and suspended solids, making them easier to separate from water. Key approaches include:

• Innovative plant-based coagulants for low pH environments
• Advanced water-based polymer solutions for efficient separation
• Specialised chemical programmes for high-fat content
  
  

Physical Separation Methods

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.

How to Implement Effective Oily Wastewater Treatment

Implementing effective oily wastewater treatment requires careful system design and ongoing monitoring. Whether upgrading existing systems or installing new solutions, understanding key implementation factors helps ensure optimal performance and cost control.

Treating oily wastewater effectively starts with proper system design. Engineers must consider several critical factors during the planning phase. Wastewater volume and oil content determine treatment capacity needs, while available space often influences technology selection. Discharge requirements set clear performance targets, and operational budgets shape the final solution design. Each factor plays a vital role in creating an efficient, reliable treatment system.

Once a treatment system is in place, consistent monitoring becomes essential for maintaining peak performance. Regular water quality testing provides crucial data about system effectiveness, while careful chemical dosage control ensures optimal treatment efficiency. Equipment maintenance schedules help prevent costly disruptions, and compliance monitoring protects against regulatory issues. These ongoing activities help maintain system performance while controlling operational costs.

In practice, these principles have helped numerous facilities overcome their oily wastewater challenges.

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.

Speaking on the inefficiencies associated with the preceding system, Brian Jones, Business Development Manager at Veolia Water Technologies, commented: “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.