Water • Treatment Microsoft Excel (.xlsx)

Disinfection CT (Chlorine Contact)

Verify chlorine residual أ— contact time against pathogen inactivation requirement.

What this workbook is

A real, downloadable Microsoft Excel workbook — not a rendered demo. Every sheet is built around a single engineering method: inputs in one place, calculated results and a PASS / WARN / FAIL check sheet, with the method, sources and assumptions recorded next to the numbers. Open it in Excel, Sheets or LibreOffice, change the inputs, and the workbook recalculates.

  • Light cells are user-entered inputs on the Inputs sheet.
  • Dark cells are calculated automatically and are not editable.
  • The method and sources for every calculation are listed below and inside the workbook.

What you enter

  • Chlorine residual (mg/L)
  • Contact volume
  • Peak flow
  • Baffling / T10 factor

What it calculates

  • T10 contact time
  • CT achieved
  • CT required (user)
  • PASS / WARN check

Method

CT = C أ— T; T10 = TDT أ— baffling factor; compare with required CT (user/regulatory)

Sources

  • [1] US EPA SWTR & disinfection profiling guidance (CT method)

Inside the workbook

CoverTitle, scope and revision block
SummaryCore inputs and headline results
InputsYour project values (light cells)
CalculationsStep-by-step working sheet (dark cells)
OutputsReadback of results for reporting
ChecksPASS / WARN / FAIL against stated limits
ReferenceSources for each calculation
Notes & AssumptionsScope, exclusions and stated limits