Case Study on Silica Grinding Wastewater Treatment with Industrial Wastewater Centrifuge

• Case Study Overview
• Introduction
• Current Scenario
• The Wastewater Centrifuge Solution
• Pilot Scale Testing
• How the Disc Stack Centrifuge Works
• Advantages of the Wastewater Centrifuge
• Cost-Benefit Analysis
• Environmental Impact
• Conclusion

Case Study Overview

Introduction

In the semiconductor industry, cutting and grinding silicon wafers with diamond blades generate large volumes of contaminated water containing fine silica and diamond particles. Traditional filtration methods often fall short of effectively cleaning this wastewater.

One silicon wafer manufacturer faced the challenge of managing over 50,000 gallons of wastewater daily, necessitating a more efficient and cost-effective solution.

Current Scenario

The facility initially employed an ultra-filtration system to purify the wastewater. However, this approach proved both expensive and difficult to maintain. Each filtration membrane costs $350 and requires replacement every 3-6 hours due to clogging from fine particles.

With four membranes needing replacement per cycle, annual membrane costs reached approximately $1,400,000. Additionally, labor costs amounted to around $33,000 annually, stemming from the frequent need to replace membranes. These maintenance demands disrupted operations and significantly increased operational expenses.

The Wastewater Centrifuge Solution

Seeking a better alternative, the facility partnered with Dolphin Centrifuge, a manufacturer of industrial centrifuge systems for wastewater. Dolphin Centrifuge recommended an industrial wastewater centrifuge specifically a disc stack centrifuge for wastewater, capable of handling 50 gallons per minute.

This centrifuge machine for wastewater effectively separates fine silica and diamond particles, achieving separation efficiencies down to a fraction of a micron.

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Pilot Scale Testing

To verify the effectiveness of the proposed centrifuge machine for wastewater, Dolphin Centrifuge conducted pilot scale testing using a 1-gallon sample of the facility’s grinding wastewater.

The results demonstrated a complete removal of particle contamination, producing clear, reusable water.

How the Disc Stack Centrifuge Works

A disc stack centrifuge for wastewater operates by using centrifugal force to separate fine particles from liquids. Key components include:

• Feed Inlet: Wastewater enters the centrifuge through a central inlet.
• Spinning Bowl: The bowl spins rapidly, generating centrifugal forces up to 10,000 Gs, which aid in particle separation.
• Disc Stack: Conical discs are tightly stacked within the bowl, increasing the surface area for separation. As wastewater flows through the disc gaps, centrifugal force drives denser particles like silica and diamond to the bowl’s edge.
• Separated Phases: Accumulated particles form sludge at the edge, while the clean liquid moves toward the center and exits through an outlet.
• Self-Cleaning Mechanism: The centrifuge periodically slows down to allow a discharge mechanism to remove sludge, ensuring continuous operation without frequent manual intervention.

Advantages of the Wastewater Centrifuge

Implementing an industrial wastewater centrifuge provides several benefits over the existing ultra-filtration system:

• Efficient Separation: The Alfa Laval centrifugal separator design effectively handles fine particles, improving the removal rates of silica and diamond.
• Continuous Operation: The centrifuge operates nonstop, enhancing productivity and reducing downtime compared to the intermittent nature of ultra-filtration.
• Labor Efficiency: Minimal maintenance and a self-cleaning mechanism reduce the need for frequent filter changes and lower labor costs.
• Environmental Impact:
  • Water Recycling: Enables the reuse of water within the facility, reducing the demand for fresh water and the volume of contaminated water requiring external treatment.
  • Reduced Chemical Usage: Lower reliance on chemical cleaning agents and disposable filters minimizes the environmental footprint.

Cost-Benefit Analysis

Ultra-Filtration System:

• Membrane Costs: $1,400,000 annually
• Labor Costs: $33,000 annually
• Total Annual Cost: $1,433,000

Centrifuge System:

• Electricity Costs: $125,000 annually
• Maintenance Costs: $4,000 annually
• Depreciation: $25,000 annually
• Total Annual Cost: $154,000

Annual Savings: Approximately $1,279,000.

Environmental Impact

Adopting a wastewater centrifuge supports sustainable practices by enabling water recycling and reducing the need for fresh water. It also decreases the volume of contaminated water requiring external disposal and lowers the use of chemical cleaning agents and disposable filters, thereby reducing the overall environmental impact.

Conclusion

Switching to a disc stack centrifuge for wastewater offers an effective solution for the silicon wafer facility’s wastewater management challenges. The industrial wastewater centrifuge efficiently handles fine particle contamination, provides significant cost and labor savings, and promotes sustainable operations.

With continuous operation, minimal maintenance, and environmental benefits, the centrifuge system is a valuable investment for high-volume wastewater treatment in the semiconductor manufacturing industry.

For more information or to schedule a consultation, contact Dolphin Centrifuge today.

Contact Dolphin Centrifuge Today