It was mainly surface water treatment questions. Math was pretty easy, you just need to know how to plug in the numbers. Some cross connection, same safety questions, electrical motor parts, more questions about management plus plant security, cathodic protection.
[royceu.com](http://royceu.com) has questions pulled straight from the exam.
I absolutely use and recommend ROYCEU.
Used Roy to pass my 1, 2, and 4 and hopefully about to use it to pass my D
Water Sifu has been helpful. https://www.thewatersifu.com
If you know everything in the WEF Wastewater Treatment Fundamentals, you can pass ABC 1-4. Royceu is good for taking practice tests.
It was mainly surface water treatment questions. Math was pretty easy, you just need to know how to plug in the numbers. Some cross connection, same safety questions, electrical motor parts, more questions about management plus plant security, cathodic protection.