Top 4 Technologies for Cleaning Wastewater in the Dairy Industry

Explore the Top 4 Technologies for Cleaning Wastewater in the Dairy Industry

Dairy Industry Sector Sustainable Technologies

The dairy industry is a significant sector within the food and beverage industry, responsible for producing milk, cheese, butter, cream, and other dairy products consumed worldwide.

As a major contributor to agricultural and economic activities, the dairy industry also generates large volumes of wastewater during processing. This wastewater is uniquely challenging to treat due to its high levels of Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), fats, oils, and grease (FOG), and various organic compounds. In addition, the waste generated from dairy plants will have high variability ranging from relatively clean to highly contaminated from one minute to the next. The complexity of dairy wastewater arises from the diverse range of activities involved in dairy processing, including pasteurization, homogenization, fermentation, and cleaning operations, all of which contribute to the contamination load.

The primary challenges in treating dairy wastewater include:

1. High Organic Load: The organic content in dairy wastewater, measured as BOD, is significantly high due to milk solids, lactose, proteins, and fats, making it difficult to biologically degrade.
2. Fats, Oils, and Grease (FOG): Dairy processes generate considerable amounts of FOG, which can clog treatment systems and require specialized pre-treatment to remove.
   Nutrient Imbalance: Dairy wastewater often has a high nitrogen and phosphorus content, leading to eutrophication if not properly managed.
3. Variable Flow Rates and Loads: The production schedules in dairy plants can lead to fluctuating wastewater volumes and concentrations, complicating treatment processes.

Given these challenges, effective treatment technologies are essential to meet environmental regulations and ensure sustainable operations.

Here, we explore the top four conventional wastewater treatment technologies, highlighting their pros and cons in addressing the specific needs of milk, cream, cheese, and other dairy processes. We also compare their energy use, footprint, maintenance requirements, and costs for a 400 gallons per minute (GPM) system. In contrast to the conventional approaches, we introduce a purely mechanical, low-footprint method to remove dairy wastewater made by Hydro Reserve.

1. Activated Sludge Process (ASP)

The Activated Sludge Process (ASP) is a conventional and widely used biological treatment method.

It involves aerating wastewater to promote the growth of microorganisms that break down organic matter, effectively reducing pollutants. ASP is particularly effective in treating high organic loads typical in dairy industry wastewater, making it a popular choice for large-scale operations.

Pros:

• TSS Removal: Highly effective through sedimentation.
• BOD Removal: Excellent at reducing BOD due to the biological degradation of organic matter over time.
• FOG Removal: Moderate efficiency; requires pre-treatment to enhance effectiveness.

Cons:

• Energy Use: High due to aeration requirements.
• Footprint: Large footprint needed for aeration tanks and secondary clarifiers.
• Maintenance: Intensive, requiring regular monitoring and sludge management. Can be subject to upsets with high wastewater loading.
• Costs: High upfront and operating costs due to energy demands and infrastructure needs.
• Reuse: The effluent from these systems cannot be reused in plant application such as in cooling towers, boiler make-up and irrigation.

Milk, Cream, and Cheese Processes: ASP is effective in treating the high organic loads typical in these processes, but the large footprint and high energy costs can be a disadvantage for a variety of facilities.

2. Membrane Bioreactor (MBR)

Membrane Bioreactor (MBR) systems combine biological treatment with membrane filtration, offering high efficiency in removing pollutants from dairy wastewater.

The integration of membranes allows for the separation of solid and liquid phases, producing high-quality effluent suitable for reuse. Compared to ASP, MBR systems are particularly advantageous in facilities with limited space due to their compact design.

Pros:

• TSS Removal: Exceptional at removing TSS due to fine membrane filtration.
• BOD Removal: Very effective, combining biological treatment with membrane filtration.
• FOG Removal: Effective when combined with pre-treatment processes.

Cons:

• Energy Use: Moderate to high, primarily due to the need for membrane aeration and pumping.
  Footprint: Smaller footprint compared to ASP due to the compact design.
• Maintenance: High maintenance required to prevent membrane fouling. Requires regular membrane removal and rinsing.
• Costs: High initial and operating costs, mainly due to membrane replacement and energy consumption. These systems also require significant manual labor to service and clean them.

Milk, Cream, and Cheese Processes: MBR systems are suitable for facilities with space constraints and high organic loads. However, the maintenance and cost of membrane replacement can be significant.

3. Dissolved Air Flotation (DAF)

Dissolved Air Flotation (DAF) is a physical-chemical process that uses air bubbles to separate suspended solids, oils, and greases from wastewater.

This technology is effective in pretreating dairy wastewater, making it a suitable choice for processes with high FOG content, such as cheese production. High BOD content can upset DAF systems, and, can incur waste surcharges to facilities if not properly managed.

Pros:

• TSS Removal: Excellent at removing suspended solids through flotation.
• BOD Removal: Effective when used in combination with other biological treatments, depending on the contacting time.
• FOG Removal: Highly effective in separating oils and greases from water, depending on the contact time.

Cons:

• Energy Use: Moderate energy consumption for air saturation and recirculation pumps.
• Footprint: Moderate footprint; relatively compact compared to ASP.
• Maintenance: Regular maintenance required to manage sludge and ensure efficient operation.
• Costs: Moderate upfront costs with ongoing operating expenses for air and chemical usage.
• Reuse: The effluent from these systems cannot be reused in plant application such as in cooling towers, boiler make-up and irrigation.

Milk, Cream, and Cheese Processes: DAF is particularly effective for cheese production, where fat and grease content is high. It provides moderate pretreatment before biological processes.

4. Sequencing Batch Reactor (SBR)

The Sequencing Batch Reactor (SBR) is a versatile and efficient biological treatment method that operates in cycles.

By using a single tank for aeration and settling, SBR systems can handle varying loads, making them suitable for the diverse wastewater characteristics found in the dairy industry.

Pros:

• TSS Removal: Effective, as settling occurs in the same tank used for aeration.
• BOD Removal: Effective, if the proper amount of time for settling occurs, due to controlled aeration cycles enhancing biological activity.
• FOG Removal: Moderate; requires pre-treatment for optimal performance.

Cons:

• Energy Use: Moderate to high, depending on the aeration and mixing cycles.
• Footprint: Smaller than conventional ASP due to the sequential use of a single tank.
• Maintenance: Moderate maintenance needed to manage cycle timing and sludge removal.
• Costs: Moderate upfront and operating costs, with savings from the reduced footprint.
• Reuse: The effluent from these systems cannot be reused in plant application such as in cooling towers, boiler make-up and irrigation.

Milk, Cream, and Cheese Processes: SBR systems are versatile and can handle varying loads, making them suitable for diverse dairy operations. The reduced footprint is beneficial for facilities with limited space.

Comparison Chart for a 400 GPM System

Formula for Capital Cost:

Total Capital Cost=GPM × 1440 × Cost per Gallon
Explanation for ASP:

To calculate the total capital cost for the ASP system, use the formula:

1. Multiply the system’s capacity in gallons per minute (GPM) by the number of minutes in a day (1440).
2. Then, multiply the result by the capital cost per gallon.
3. Example Calculation: For a 400 GPM ASP system with a capital cost of $8.00 per gallon:
4. Total Capital Cost= 400 GPM × 1440 minutes / day × 8.00 $/gallon=$4,608,000
5. So, the total capital cost for the ASP system is $4,608,000.

Hydro Reserve’s Modified Ultra-Filtration Approach

Hydro Reserve’s modified ultra-filtration (UF) technology offers a highly efficient solution for treating dairy industry wastewater, addressing many of the limitations of conventional methods. 

This approach uses mechanical barriers instead of bacteria to filter contaminants, providing several key benefits:

• Smaller Footprint: The compact design of the modified UF system requires significantly less space compared to traditional biological treatment methods, making it ideal for dairy facilities with limited space. Typically, it occupies less than 700 square feet for a 400 GPM system.
• Cleaner Water Output: The UF technology produces cleaner water by effectively removing TSS, BOD, and FOG through fine filtration, resulting in high-quality effluent suitable for various reuse applications including cooling towers, boilers, irrigation, and initial CIP.
• Mechanical Barrier: By employing a mechanical filtration process, the system avoids the complexities and maintenance issues associated with biological treatment. This approach ensures consistent performance without the variability linked to biological processes.
• Energy Efficiency: Hydro Reserve’s UF system consumes less energy compared to aeration-based technologies, reducing operational costs and the facility’s environmental footprint.
• Reduced Maintenance: The mechanical nature of the UF system simplifies maintenance, requiring less frequent intervention and lowering long-term operational costs.
• Cost Efficiency: Utilizing a Build Own Operate Maintain model (BOOM) Hydro Reserve helps dairy processors reduce costs by taking complete ownership and responsibility of the ongoing operation of the system. With a pricing model based on both flow rate and contaminant levels it presents a highly economic way to treat dairy wastewater without hidden costs, the requirement for wastewater staff or the need to pay for fluctuating volumes of chemicals.

Conclusion

In conclusion, Hydro Reserve’s modified ultra-filtration technology presents a superior option for treating wastewater in the dairy industry. Its smaller footprint, ability to generate cleaner water, and reliance on a mechanical barrier instead of biological processes make it a reliable and cost-effective choice for facilities aiming to meet stringent dairy wastewater treatment standards while optimizing space and reducing operational expenses.