Wastewater operator continuing education

Disinfection CT: Contact Time Is Not Volume/Flow

Approved in Illinois — not yet released for enrollment

Tank volume divided by flow can overstate your real contact time, because water short-circuits through the tank. This hour shows what actually sets contact time and how to judge whether your disinfection is really working.

Course summary, as it appears on your certificate

To correct common misconceptions about disinfection contact time (CT) by demonstrating that contact time is governed by actual water residence time and mixing behavior, not simply nominal tank volume divided by flow rate, and to provide operators with practical knowledge to accurately assess and manage disinfection performance to ensure regulatory compliance and protect public health.

We can't sell this in Illinois yet. Tell us where you are and we'll email you the day it opens — nothing else, and one click to stop. Tell me when it opens

Level 1 — what it is and why — the foundations, for operators new to the subject or wanting a refresher

Credit awarded: 1 hour — Technical

The Illinois course number is issued by the Agency for this course and is printed on your certificate.

One hour of study is one hour of credit. Your certificate reports the hours, which is what Illinois records against your renewal.

What's included

  • Self-paced online coursework you can start, pause, and resume anytime
  • Short questions along the way, and a short final quiz to pass for your certificate (retake it as often as you need)
  • An official certificate of completion (PDF) with a public verification code
  • Progress saved to your My Learning dashboard
$19.00 USD

One-time payment · lifetime access to this course

About 74 minutes of video · 1 hour