,TEXAS WASTEWATER CLASS D CERTIFICATION EXAM
STUDY GUIDE 2026 – COMPLETE PRACTICE QUESTIONS,
VERIFIED ANSWERS, OPERATOR TRAINING NOTES,
LICENSING PREPARATION & REAL EXAM SUCCESS
MATERIALS
, Texas Wastewater Class D Exam
Question 1
Which of the following is the primary purpose of a wastewater treatment plant?
A) To generate electricity
B) To recycle water
C) To remove contaminants from wastewater
D) To increase water temperature
Correct Option: C
Rationale: The primary purpose of a wastewater treatment plant is to remove contaminants
from wastewater to protect public health and the environment.
Question 2
What is the acceptable pH range for treated wastewater?
A) 4.0 - 6.0
B) 6.5 - 8.5
C) 6.0 - 9.0
D) 8.5 - 10.5
Correct Option: C
Rationale: The acceptable pH range for treated wastewater is typically between 6.0 and 9.0 to
ensure it is safe for discharge and not harmful to aquatic life.
Question 3
Which process is primarily used for the removal of suspended solids in wastewater
treatment?
A) Filtration
B) Aeration
STUDY GUIDE 2026 – COMPLETE PRACTICE QUESTIONS,
VERIFIED ANSWERS, OPERATOR TRAINING NOTES,
LICENSING PREPARATION & REAL EXAM SUCCESS
MATERIALS
, Texas Wastewater Class D Exam
Question 1
Which of the following is the primary purpose of a wastewater treatment plant?
A) To generate electricity
B) To recycle water
C) To remove contaminants from wastewater
D) To increase water temperature
Correct Option: C
Rationale: The primary purpose of a wastewater treatment plant is to remove contaminants
from wastewater to protect public health and the environment.
Question 2
What is the acceptable pH range for treated wastewater?
A) 4.0 - 6.0
B) 6.5 - 8.5
C) 6.0 - 9.0
D) 8.5 - 10.5
Correct Option: C
Rationale: The acceptable pH range for treated wastewater is typically between 6.0 and 9.0 to
ensure it is safe for discharge and not harmful to aquatic life.
Question 3
Which process is primarily used for the removal of suspended solids in wastewater
treatment?
A) Filtration
B) Aeration
