Ozone Dosing & CT Calculator
Size the ozone generator for a target applied dose and contact basin, then verify EPA Cryptosporidium CT compliance (40 CFR §141.720) at your actual water temperature, baffling factor, and residual — with clear 1-Log / 2-Log / 3-Log pass/fail results.
Standard Compliance
Need a full ozone system design?
This tool provides preliminary dosing and CT verification. For ozone demand testing, off-gas destruct sizing, or full contact basin hydraulic design, our engineers can support a complete system package.
Request ConsultationExport Capabilities
- Full dosing and generator sizing breakdown
- CT compliance check against 40 CFR §141.720(b)(2)
- 1-Log / 2-Log / 3-Log pass/fail with compliance margin
- Print-ready PDF report
Ozone Dosing & CT Calculator
Size the ozone generator for a target applied dose, then verify EPA Cryptosporidium CT compliance for the contact basin.
Typical for a well-designed venturi/fine-bubble injection system: 85-95%. Older or poorly-matched systems can run materially lower (50-70%) — confirm against actual equipment/injector performance data.
Values shown are the official published table at the 6 temperatures below; this tool's pass/fail check uses EPA's own continuous equation (footnote 1 to the table) for the exact entered temperature, which reproduces these values at each breakpoint.
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Engineering Methodology
CT compliance follows the official US EPA Long Term 2 Enhanced Surface Water Treatment Rule (40 CFR §141.720(b)(2)) Cryptosporidium ozone CT table, evaluated via its own sanctioned continuous equation — Log credit = (0.0397 × 1.09757^Temp) × CT — which reproduces the published table exactly at every tabulated temperature. T10 is computed as hydraulic retention time (contact volume ÷ flow) times a baffling factor from the standard EPA/AWWA contact-basin classification (0.1 unbaffled to 0.7 superior).
Theoretical ozone rate (g/h) equals flow (m³/h) times target applied dose (mg/L) — dimensionally exact, since 1 mg/L applied across 1 m³/h is 1 gram of ozone per hour. Required generator output divides that rate by the transfer efficiency of the injection/contact system, since not all generated ozone dissolves into the water — typical well-designed systems achieve 85-95%, and this should be confirmed against actual equipment performance.
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