Wastewater Treatment & Pollution Load Calculator

Water Engineering & Environmental Compliance Tool

Calculate pollution load, required tank volume, effluent concentration, and more. Ideal for engineers, students, and environmental professionals.

Example Calculations

Try these sample wastewater scenarios to see how the calculator works

Standard Municipal Wastewater

Municipal Wastewater

A typical municipal wastewater scenario with BOD removal.

Flow Rate: 15

Concentration: 250 mg/L

HRT: 8 hour

Removal Efficiency: 85%

Tank Volume: 0 m³

Flow Unit: L/s (Liters/Second)

Pollutant Type: BOD (Biochemical Oxygen Demand)

Industrial Effluent with High COD

Industrial Effluent

Industrial wastewater with high COD concentration and moderate removal efficiency.

Flow Rate: 120

Concentration: 1200 mg/L

HRT: 10 hour

Removal Efficiency: 70%

Tank Volume: 0 m³

Flow Unit: m³/h (Cubic Meters/Hour)

Pollutant Type: COD (Chemical Oxygen Demand)

Small Community TSS Removal

Small Community

A small community with low flow and TSS as the main pollutant.

Flow Rate: 50

Concentration: 180 mg/L

HRT: 6 hour

Removal Efficiency: 90%

Tank Volume: 0 m³

Flow Unit: m³/day (Cubic Meters/Day)

Pollutant Type: TSS (Total Suspended Solids)

Existing Tank Volume Scenario

Existing Tank

Calculate HRT for an existing tank with known volume.

Flow Rate: 20

Concentration: 300 mg/L

HRT: 0 hour

Removal Efficiency: 80%

Tank Volume: 200 m³

Flow Unit: L/s (Liters/Second)

Pollutant Type: BOD (Biochemical Oxygen Demand)

Other Titles
Understanding Wastewater Treatment & Pollution Load: A Comprehensive Guide
Master wastewater calculations for environmental compliance and plant design

What is Wastewater Treatment & Pollution Load?

  • Definition of Wastewater
  • Pollution Load Concepts
  • Importance in Environmental Engineering
Wastewater treatment is the process of removing contaminants from water discharged from homes, industries, and businesses. Pollution load refers to the total amount of a specific pollutant (e.g., BOD, COD, TSS) entering a treatment system per day.
Why Calculate Pollution Load?
Calculating pollution load is essential for designing treatment plants, ensuring regulatory compliance, and protecting the environment. It helps determine the size of treatment units and the efficiency required to meet discharge standards.
Key Parameters in Wastewater Calculations
Key parameters include flow rate, pollutant concentration, removal efficiency, and tank volume. Understanding these allows for accurate system sizing and performance assessment.

Pollution Load Examples

  • A city with 100,000 people generates 20,000 kg BOD/day.
  • Industrial plant discharges 1,200 kg COD/day.

Step-by-Step Guide to Using the Wastewater Calculator

  • Input Flow and Concentration
  • Set Treatment Parameters
  • Interpret Results
The calculator guides users through entering flow rate, selecting units, and specifying pollutant concentration. Users then set treatment parameters such as HRT and removal efficiency.
Entering Flow and Units
Input the flow rate and select the appropriate unit (L/s, m³/h, m³/day). The calculator automatically converts all values to m³/day for consistency.
Specifying Pollutant and Efficiency
Choose the pollutant type (BOD, COD, TSS) and enter its concentration in mg/L. Set the expected removal efficiency as a percentage.
Tank Volume and HRT
If you know the tank volume, enter it to calculate HRT. Otherwise, specify HRT to estimate required tank volume.

Step-by-Step Examples

  • Flow: 15 L/s, BOD: 250 mg/L, HRT: 8 h, Efficiency: 85%
  • Flow: 120 m³/h, COD: 1200 mg/L, HRT: 10 h, Efficiency: 70%

Real-World Applications of Wastewater Calculations

  • Municipal Plant Design
  • Industrial Effluent Management
  • Environmental Compliance
Wastewater calculations are used in municipal plant design, industrial effluent management, and regulatory compliance. Accurate calculations ensure efficient treatment and environmental protection.
Municipal Applications
Cities use these calculations to size treatment plants and meet discharge limits. Population growth and industrialization increase the importance of accurate design.
Industrial Applications
Industries must treat effluent to meet legal standards. Calculators help optimize treatment processes and minimize costs.
Environmental Protection
Proper wastewater treatment prevents water pollution, protects aquatic life, and ensures safe water for communities.

Application Examples

  • Municipal plant for 50,000 people
  • Industrial factory with high COD discharge

Common Misconceptions and Correct Methods

  • Unit Conversion Errors
  • Ignoring Removal Efficiency
  • Incorrect Tank Sizing
Common mistakes include incorrect unit conversions, neglecting removal efficiency, and improper tank sizing. Understanding the correct methods ensures reliable results.
Unit Conversion Pitfalls
Always convert flow rates to a consistent unit (m³/day) before calculations. Mixing units leads to significant errors in pollution load and tank sizing.
Importance of Removal Efficiency
Removal efficiency directly affects effluent quality and pollutant removal. Always use realistic values based on treatment technology.
Tank Sizing Best Practices
Tank volume should be based on flow rate and HRT. Oversized or undersized tanks reduce treatment efficiency and increase costs.

Best Practice Guidelines

  • Don't use L/s and m³/h together
  • Always include removal efficiency in calculations
  • Check tank volume against HRT

Mathematical Derivation and Examples

  • Pollution Load Formula
  • Tank Volume Calculation
  • Effluent Quality Estimation
Pollution load (kg/day) = Flow (m³/day) × Concentration (mg/L) × 0.001. Required tank volume (m³) = Flow (m³/day) × HRT (h) / 24. Effluent concentration (mg/L) = Influent × (1 - Removal Efficiency/100).
Worked Example: Municipal Wastewater
Given: Flow = 15 L/s, BOD = 250 mg/L, HRT = 8 h, Efficiency = 85%. Convert flow: 15 L/s × 86.4 = 1,296 m³/day. Pollution load: 1,296 × 250 × 0.001 = 324 kg/day. Required tank: 1,296 × 8 / 24 = 432 m³. Effluent: 250 × (1-0.85) = 37.5 mg/L.
Worked Example: Industrial Effluent
Given: Flow = 120 m³/h, COD = 1,200 mg/L, HRT = 10 h, Efficiency = 70%. Convert flow: 120 × 24 = 2,880 m³/day. Pollution load: 2,880 × 1,200 × 0.001 = 3,456 kg/day. Required tank: 2,880 × 10 / 24 = 1,200 m³. Effluent: 1,200 × (1-0.7) = 360 mg/L.

Calculation Examples

  • Municipal: 324 kg BOD/day, 432 m³ tank, 37.5 mg/L effluent
  • Industrial: 3,456 kg COD/day, 1,200 m³ tank, 360 mg/L effluent