FREE WW Sludge Processing and Disposal Questions and Answers

Question 1

In the operation of a belt filter press, what is the primary purpose of adding polymer to the sludge before it enters the press?

Accepted Answer

To condition the sludge by promoting flocculation

Answer

To disinfect the sludge and kill pathogens

Answer

To raise the pH and stabilize the sludge

Answer

To reduce odors before dewatering

Question 2

Which sludge thickening process uses fine air bubbles to attach to solids and float them to the surface for removal?

Accepted Answer

Dissolved Air Flotation (DAF)

Answer

Gravity Thickening

Answer

Rotary Drum Thickening

Answer

Centrifugation

Question 3

The primary goal of anaerobic digestion is to reduce volatile solids and produce which valuable byproduct gas?

Accepted Answer

Methane (CH₄)

Answer

Oxygen (O₂)

Answer

Hydrogen Sulfide (H₂S)

Answer

Nitrogen (N₂)

Question 4

According to EPA 503 regulations, what distinguishes Class A biosolids from Class B biosolids?

Accepted Answer

Class A meets stricter pathogen reduction requirements than Class B

Answer

Class A has a higher nutrient content than Class B

Answer

Class A has a lower heavy metals concentration than Class B

Answer

Class A can only be disposed of in a landfill, while Class B can be land-applied

Question 5

What is the primary mechanism by which adding large quantities of lime stabilizes sludge?

Accepted Answer

It raises the pH to a level that inhibits microbial activity

Answer

It binds with heavy metals to make them inert

Answer

It adds beneficial bacteria to the sludge

Answer

It causes a thermophilic reaction that sterilizes the sludge

Question 6

In a dewatering centrifuge, the separated, clarified liquid that is removed is referred to as:

Accepted Answer

Centrate

Answer

Filtrate

Answer

Cake

Answer

Supernatant

Question 7

Aerobic digestion is a sludge stabilization process that primarily reduces which component of the sludge?

Accepted Answer

Volatile solids

Answer

Inert solids

Answer

Total dissolved solids

Answer

Heavy metals