Pretreatment

Identify the statements that are true about using a pretreatment process on a water source that has large quantities of debris, gravel or sand,

• If not removed this material clog pipes.

• If not removed this material can damage pumps.

• Pretreatment can reduce the amount of chemicals used in the treatment process.

Which of the following is a principal problem associated with preliminary treatment screening?

• Clogging

• Broken screens

• Excessive downtime due to numerous shear pins being broken

• Chain comes out of the foot sprocket

Bar screen assemblies are installed in a waterway at a(n) __________ angle.

• 60 - 80 degrees

• 40 - 60 degrees

• 80 - 90 degrees

• 90 - 120 degrees

Which of the following is not a term used to rank the distance between bars in a bar screen?

• Wide

• Fine

• Medium

• Coarse

Shear pins are usually installed where the drive motor is attached to the screen drive gear to prevent overload of the motor.

• True

• False

________ is a pretreatment process used to remove gravel, sand and silt from the raw water before it enters the main treatment facility.

• Presedimentation

• Screening

• Preoxidation

• Microstraining

What is the opening size for medium ranked fixed screens or bar screens?

• Greater than 1/2 inch to less than 1-1/4 inch

• Greater than or equal to 1/16 in. to less than or equal to ½ in.

• Greater than or equal to 1 ¼ in. to less than or equal to 4 in.

What is the first pretreatment provided in most surface water treatment?

• Screening

• Coagulation

• Flocculation

• Disinfection

What details are included in complete, up-to-date operating records for screening equipment?

• Date of inspection

• Amount of material removed

• Types of material removed

• Unusual or unexpected types of debris

• Unusual or unexpected water conditions

Identify the preferred methods to control algae and plant growth in a pre-sedimentation reservoir.

• Chemicals

• Linings

• Covers

• Multiple reservoirs