Note:

This calculator determines the Filter Efficiency (E) using Rankin’s Equation, which is essential for designing and evaluating trickling filters in wastewater treatment systems.

It is widely used in environmental engineering, sewage treatment, and pollution control systems to estimate biological filter performance and ensure compliance with discharge standards.

Explanation of Parameters:

• Recirculation Flow Rate (R): The volume of treated water being recirculated back into the filter (m³/day).
• Influent Flow Rate (Q): The raw sewage entering the filter (m³/day).
• R/Q Ratio: Ratio of recirculated to raw sewage flow. Controls the degree of contact between microbes and organic matter.

Why This Calculator Belongs to the Environment Sector?

This Filter Efficiency Calculator is categorized under the Environment sector as it directly contributes to wastewater treatment, pollution reduction, and sustainable water management. It supports the design and evaluation of biological filters used to reduce BOD levels in effluent.

Why is Filter Efficiency Important?

Determining filter efficiency is essential for:

• Regulatory Compliance: Meeting discharge limits for biochemical oxygen demand (BOD).
• System Optimization: Improving treatment performance by adjusting recirculation.
• Design Validation: Ensuring proper sizing of filters and recirculation flow rates.

Validations:

• Positive Input Values: Both R and Q must be positive numbers.
• Practical Ratio: R/Q ratio should typically be between 0.5 and 2.5 for standard designs.
• Application Rule: Ensure BOD loading ≤ 1.2 kg BOD₅/day/m³ of filter volume.
• Hydraulic Limit: Flow rate (including recirculation) ≤ 30 m³/m²/day.
• Operational Rule: BOD entering the filter ≤ 3 × expected effluent BOD.

Real-life Applications:

• Municipal Sewage Treatment: Evaluating trickling filter performance for domestic wastewater.
• Industrial Effluent Systems: Optimizing biological filters for organic load reduction.
• Decentralized Treatment: Used in small-scale environmental setups with limited resources.
• Environmental Impact Management: Ensures treated water quality before discharge into natural water bodies.

Conclusion:

The Rankin’s Equation-based Filter Efficiency Calculator is a vital tool in environmental engineering. It enables engineers and environmental scientists to design efficient treatment systems that protect water resources and public health.