STP Capacity Calculator
Calculate sewage treatment plant design flows from population data using CPHEEO norms. Get average flow, peak flow, and recommended STP capacity in KLD or MLD.
Free · Based on CPHEEO Manual (3rd Edition)Design Parameters
Based on CPHEEO Manual on Sewerage and Sewage Treatment (3rd Edition).
Use projected population at end of design period (typically 30 years)
How to Use This Calculator
- 1Enter the design population — the projected population at the end of the design period (typically 30 years from the project year).
- 2Select the per capita water supply rate as per CPHEEO norms for your project area — 135 lpcd is the standard for urban areas.
- 3Click "Calculate STP Capacity" to get average sewage flow, peak flow, and recommended design capacity with 20% contingency.
Formula & Methodology
Water Demand (KLD) = Population × Per Capita Supply (lpcd) ÷ 1000
Average Sewage Flow = Water Demand × 0.80 (80% return factor)
Peak Flow = Average Sewage Flow × Peak Factor
Design Capacity = Average Sewage Flow × 1.20 (20% contingency)
CPHEEO Per Capita Norms
| Area Type | Per Capita (lpcd) |
|---|---|
| Rural | 40 |
| Semi-urban | 70 |
| Small towns (<1 lakh) | 100 |
| Urban (standard) ★ | 135 |
| Metro cities | 150 |
Designing an STP for Your Project?
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