Oily Wastewater Disposal in Singapore: Things That You Need To Know!

November 29, 2023

Oily wastewater, often referred to as oily water, constitutes a mixture of water, oils, greases, and hydrocarbons. Originating primarily as a byproduct of industrial and commercial operations, this wastewater encompasses substances like motor oil, lubricants, and residual fuels. 

The responsible disposal of such oily wastewater is imperative to prevent environmental degradation and ensure the protection of human well-being. Incorrect disposal practices can result in water pollution, soil taint, and the degradation of aquatic ecosystems. 

Sources Of Oily Water

The world we inhabit is a delicate ecosystem where every action ripples across a vast interconnected network. In this intricate web, the sources of oily wastewater play a significant role, leaving an indelible mark on both our environment and daily lives.

Industrial and Manufacturing Activities

Industries drive economies, creating products that shape our world. However, this growth often comes at a cost – the generation of oily wastewater. From the manufacturing of electronics to textiles, industries rely on various substances, including lubricants and cutting fluids, which eventually mix with water to create oily wastewater. These complex concoctions of contaminants pose a challenge to responsible disposal.

Maritime and Port Operations

The maritime domain, with its bustling ports and maritime operations, is another significant contributor to oily wastewater. Vessels rely on lubricants, fuel, and hydraulic fluids to traverse the seas efficiently. Yet, as these vessels navigate, oily residue can find its way into the water. Moreover, ship maintenance activities further compound the issue, releasing waste oils that demand careful management.

Automotive and Vehicle Maintenance

Every time a vehicle takes to the road, it leaves behind traces of oils, grease, and fuel residues. While essential for smooth operation, these substances eventually find their way into stormwater runoff, which can contaminate water bodies. Additionally, vehicle maintenance activities, including oil changes and engine repairs, contribute to the generation of oily wastewater.

Other Potential Sources

Beyond these prominent sources, a spectrum of potential contributors exists. These might include small-scale commercial operations, workshops, and facilities that utilise oils and greases as part of their operations. As these sources combine forces, they create a complex challenge that demands comprehensive solutions.

Regulatory Framework for Oily Wastewater Disposal in Singapore

Singapore, a highly developed and environmentally conscious nation, places significant emphasis on regulating the disposal of oily wastewater to safeguard its water bodies and maintain ecological balance. With its limited water resources and commitment to sustainable practices, the city-state has established a comprehensive regulatory framework for the management and disposal of oily wastewater.

Main Regulatory Authorities

There are several regulatory authorities oversee different aspects of oily wastewater disposal in Singapore, and they are:

1. National Environment Agency (NEA)

The primary agency responsible for environmental protection in Singapore. They formulate and enforce regulations that are related to waste management, pollution control, and environmental sustainability.

2. Maritime and Port Authority of Singapore (MPA)

The MPA focuses on regulating maritime activities, including vessel operations and port activities. It enforces rules related to the discharge of oily water from ships and vessels.

Key Regulations and Compliance Measures

1. The Environmental Protection and Management Act (EPMA)
   The cornerstone of Singapore's environmental governance, the Environmental Protection and Management Act (EPMA), was enacted in 1999. This act serves as a powerful tool for managing pollution, conserving resources, and regulating activities with environmental impact. The EPMA empowers regulatory authorities, such as the National Environment Agency (NEA), to enforce regulations related to waste management, pollution control, and environmental quality.
   
   
2. Hazardous Waste (Control of Export, Import and Transit) Regulations
   This regulation oversees the import, export, and transit of hazardous waste, including oily wastewater. Permits are required for such movements, ensuring proper disposal and preventing the transboundary movement of hazardous waste.
   
   
3. Merchant Shipping (Civil Liability and Compensation for Bunker Oil Pollution) Act
   This act places liability on shipowners and operators for oil pollution damage caused by their vessels. It ensures that shipowners have adequate insurance coverage to address potential pollution incidents.

Common Oily Wastewater Treatment and Separation Methods

1. Gravity Separation Techniques

Gravity separation techniques harness the force of gravity to separate substances based on their varying densities. In the context of oily wastewater treatment, these techniques focus on separating lighter oil droplets from the denser water matrix. This process relies on the fact that oil droplets have a lower density compared to water, causing them to rise to the surface when provided with the opportunity.

Types of Gravity Separation Techniques

There are several gravity separation techniques employed for oily wastewater treatment:

1. API Separators (American Petroleum Institute): These separators consist of large tanks equipped with internal structures to facilitate oil-water separation. As wastewater flows through the tank, the oil rises to the surface due to its lower density, forming a distinct layer that can be skimmed off.
2. Hydrocyclone Separators: Hydrocyclones utilise centrifugal forces to separate oil from water. Wastewater enters the hydrocyclone at high velocity, causing a rotational motion that pushes oil droplets towards the outer wall, where they can be collected.

Benefits

• Efficiency: Gravity separation is a highly efficient method for removing oil droplets from water due to its reliance on natural forces.
• Low Energy Consumption: These techniques require minimal energy input, making them cost-effective and environmentally friendly.
• Complementary Approach: Gravity separation techniques can be integrated with other treatment methods to achieve comprehensive wastewater treatment.

2. Coalescing Plates and Skimmers

This technique relies on coalescence, where small oil droplets combine into larger ones. Coalescing plates offer an ideal surface for droplets to gather, rise due to their lower density, and eventually separate from the water for skimming.

Design and Operation

Coalescing plates feature closely spaced or corrugated surfaces creating narrow passages for oily wastewater flow. These passages foster the merging of small oil droplets into larger ones. Proper plate design and spacing are crucial for optimising coalescence efficiency.

In contrast, skimmers physically remove the floating oil layer from the water. They typically employ rotating drums or belts to collect oil, transferring it to a separate chamber.

Benefits

Coalescing plates and skimmers offer numerous benefits in oily wastewater treatment:

• Enhanced Efficiency: The coalescence mechanism allows for the efficient removal of smaller oil droplets, leading to higher treatment efficiency.
• Compact Design: These mechanisms are often compact and require minimal space, making them suitable for various industrial settings.
• Low Energy Consumption: Coalescing plates and skimmers operate with minimal energy consumption, contributing to cost-effective treatment solutions.

3. Dissolved Air Flotation (DAF) Systems

These systems work based on air solubility. The process starts by saturating oily wastewater with air under high pressure. When this air-saturated water is released into a flotation tank, the reduced pressure makes the dissolved air form tiny bubbles. These microbubbles adhere to oil droplets, solids, and contaminants, causing them to rise to the surface.

A skimming mechanism removes the floated material from the water, leaving clarified water with less oil content. DAF system efficiency depends on factors like bubble size, detention time, and tank design.

Benefits 

DAF systems offer several benefits that make them an attractive choice for oily wastewater treatment:

• Effective Oil Removal: These systems excel at removing small oil droplets and suspended solids from wastewater.
• Enhanced Clarification: The system not only removes oil and contaminants but also clarifies water, resulting in improved water quality.
• Low Chemical Usage: While coagulants and flocculants can be used in conjunction with the system, the process itself requires relatively fewer chemicals compared to other treatment methods.

On-Site Oily Wastewater Management

On-site oily wastewater management is a critical aspect of maintaining environmental sustainability and regulatory compliance for industries that generate oily water as a byproduct of their operations. Industries such as manufacturing, automotive, mining, and oil and gas production often generate significant amounts of oily wastewater, which requires proper treatment and disposal to prevent environmental contamination.

Utilisation of Oil-Water Separators and Clarifiers

Oil-water separators and clarifiers are vital tools in the effective treatment of oily wastewater. These devices work by utilising the differences in density between oil and water to separate and remove oil particles from the water. The separation process involves three main stages: inlet, separation, and outlet.

• Inlet Stage: Inflowing oily wastewater is introduced into the separator or clarifier. At this stage, the water may contain a mixture of free oil, emulsified oil, and suspended solids.
• Separation Stage: Once inside the device, the wastewater undergoes a process of settling. Due to the varying densities, oil rises to the surface as a distinct layer, while heavier solids settle at the bottom. Treated water occupies the middle layer.
• Outlet Stage: The treated water, located in the middle layer, is carefully collected and extracted from the system. It has undergone a significant reduction in oil and solid content.

Best practices for utilising oil-water separators and clarifiers include

• Maintenance Routine
  Develop a regular maintenance schedule that includes cleaning, inspection, and parts replacement. Neglecting maintenance can lead to reduced performance and potential system failures.
  
  
• Monitoring and Adjustments
  Install monitoring systems to track the performance of the separator or clarifier. If the oil content in the treated water exceeds permissible levels, adjustments should be made promptly.
  
  
• Operator Training
  Properly train personnel responsible for operating and maintaining the equipment. This ensures safe and effective usage while minimising errors.
  
  
• Chemical Treatment
  Depending on the type of oily wastewater, chemical additives may enhance separation efficiency. However, please consult with experts first to determine the appropriate chemicals and dosages before you do anything!

Proper Handling and Storage of Oily Water

Improper handling and storage of oily water can lead to spills, leaks, and contamination of the surrounding environment. Best practices for handling and storing oily water include:

• Containment: Store oily water in designated containers that are properly sealed to prevent leaks and spills.

• Segregation: Keep oily water containers away from other hazardous materials to avoid cross-contamination.

• Regular Inspection: Inspect containers and storage areas regularly for signs of deterioration, leaks, or other issues that could compromise containment.

Preventive Maintenance of Equipment

Regular maintenance of oil-water separators, clarifiers, and other related equipment is essential to ensure their continued functionality and longevity. Preventive maintenance practices include:

• Scheduled Inspections: Establish a routine inspection schedule to identify and address any wear and tear, corrosion, or mechanical issues.
  
  
• Cleaning and Calibration: Regularly clean the equipment to prevent buildup of oil, solids, and debris. Calibrate instruments and sensors for accurate readings.
  
  
• Replacement of Parts: Replace worn-out or damaged parts promptly to prevent breakdowns and maintain efficient operation.
  
  
• Staff Training: Train personnel in proper equipment operation, maintenance procedures, and safety protocols to ensure effective and safe maintenance practices.

Off-Site Oily Wastewater Disposal Options

Industries that generate oily wastewater are faced with the responsibility of managing this waste efficiently and in an environmentally sound manner. Off-site disposal options offer effective solutions to ensure that oily wastewater is treated, disposed of, or repurposed responsibly.

Collaboration with Licensed Waste Management Companies

Collaborating with licensed waste management companies such as GreenTec Energy is a common approach to off-site disposal of oily wastewater. These companies specialise in collecting, treating, and disposing of hazardous and non-hazardous wastes, ensuring compliance with regulatory standards. Key benefits of this approach include:

• Expertise: Licensed waste management companies have the expertise and resources to handle oily wastewater safely and efficiently.
  
  
• Regulatory Compliance: These companies are well-versed in the complex regulations surrounding waste disposal, reducing the risk of non-compliance.
  
  
• Tracking and Documentation: Collaboration with licensed companies ensures proper tracking, documentation, and reporting of the disposal process, contributing to transparency and accountability.

Recycling and Reuse of Treated Oily Water

Treated oily water can often be recycled and reused within certain industrial processes, reducing both waste generation and water consumption. This approach has several advantages:

• Resource Conservation: Recycling treated oily water conserves freshwater resources by substituting treated water for raw water in industrial operations.
• Cost Savings: Reusing treated water reduces the need for purchasing and treating additional water, leading to cost savings.
• Environmental Benefits: Recycling water reduces the overall environmental impact by decreasing the demand for natural water sources.

Ship-to-Shore Oily Water Disposal Facilities

Industries located near water bodies, such as ports or coastal areas, can make use of ship-to-shore oily water disposal facilities. These facilities provide ships with the means to offload their oily wastewater for proper treatment and disposal on land. Key advantages include:

• Preventing Marine Pollution: Ship-to-shore facilities prevent the discharge of untreated or minimally treated oily water into water bodies, minimising marine pollution.
• Regulatory Compliance: These facilities ensure that vessels comply with regulations that prohibit the discharge of oily wastewater beyond certain limits.

Challenges and Solutions in Oily Wastewater Disposal

Effectively managing oily wastewater disposal presents industries with various challenges, from regulatory compliance to sustainable practices. However, these challenges also come with opportunities for innovative solutions.

Ensuring Compliance with Environmental Regulations

Challenge: Meeting stringent environmental regulations and standards for oily wastewater disposal is a primary concern. Non-compliance can result in penalties, reputational damage, and harm to ecosystems.

Solution: Developing a robust regulatory compliance strategy involves understanding and staying updated on relevant regulations. This includes thorough documentation, regular monitoring, and implementing best practices to prevent violations. Collaborating with regulatory bodies can foster a better understanding of expectations.

Managing High-Volume Oily Water from Industrial Sources

Challenge: Industries with high production volumes often face the challenge of efficiently managing and disposing of large quantities of oily wastewater.

Solution: Implementing on-site treatment systems, such as oil-water separators and clarifiers, can help manage high-volume oily water at its source. These systems can significantly reduce the volume of oil and solids in wastewater, making it more manageable for off-site disposal.

Awareness and Training for Proper Disposal Practices

Challenge: Insufficient awareness and training among employees regarding proper oily wastewater disposal practices can lead to mistakes and non-compliance.

Solution: Conduct regular training sessions for employees involved in handling oily wastewater. Training should cover proper disposal procedures, the importance of regulatory compliance, and the environmental impact of improper disposal. Employee awareness campaigns can foster a culture of responsible waste management.

Cost-effective and Sustainable Disposal Solutions

Challenge: Balancing cost-effectiveness with sustainable disposal practices can be challenging, as some eco-friendly options may be more expensive.

Solution: Seek innovative ways to offset costs, such as exploring recycling and reuse options for treated water. Investigate waste-to-energy technologies that can generate energy while minimising waste. Collaborate with waste management companies to find mutually beneficial solutions.

Conclusion

In conclusion, oily wastewater management is an urgent environmental challenge across industries, originating from sources like industry, maritime activities, and vehicle maintenance. Singapore's strong regulations led by the NEA and MPA enforce responsible disposal.

Effective methods, like gravity separation and dissolved air flotation, remove oil. Chemical treatments, filtration, and emulsion breakers enhance separation. On-site management with oil-water separators is crucial.

Feel free to contact us if you're looking for expert assistance in implementing these strategies and ensuring responsible oily wastewater management for your business.