Waste Treatment Technologies and Disposal Methods Flashcards
7 cards from real CPWM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Waste Treatment Technologies and Disposal Methods flashcards as text
Which chemical stabilization agent is most commonly used in solidification/stabilization (S/S) treatment of heavy metal-contaminated waste?
Answer: Portland cement
Portland cement is the most widely used binder in S/S treatment because it immobilizes heavy metals through precipitation and physical encapsulation.
In rotary kiln incineration of hazardous waste, the secondary combustion chamber primarily serves to:
Answer: Ensure complete combustion of organics by providing additional residence time at high temperature
The secondary combustion chamber provides additional high-temperature residence time to destroy unburned organic gases escaping the primary kiln.
What is the purpose of 'intermediate cover' in landfill operations compared to 'daily cover'?
Answer: Intermediate cover uses thicker compacted soil to seal areas inactive for more than 30 days
Intermediate cover is a thicker soil layer (typically 12 inches) applied to areas that will be inactive for 30 days or more, providing additional protection compared to daily cover.
Wet scrubbers in waste incinerators are used primarily to remove:
Answer: Acid gases such as hydrogen chloride and sulfur dioxide
Wet scrubbers contact flue gas with an alkaline liquid solution to neutralize and remove acid gases like HCl and SO₂.
Which waste disposal method is specifically prohibited for listed hazardous wastes under the EPA Land Disposal Restrictions (LDR) program unless treatment standards are met?
Answer: Placement in any land disposal unit
LDR prohibits land disposal of untreated listed hazardous waste; wastes must meet specific treatment standards (Best Demonstrated Available Technology) before land placement.
What is 'air curtain incineration' and when is it most commonly used?
Answer: A technique using pressurized air jets to enhance combustion of woody debris in a pit or box
Air curtain incineration uses a high-velocity air jet over a pit or box to create turbulence that improves combustion, commonly used for land clearing debris after disasters.
In landfill final cover system design, the drainage layer serves to:
Answer: Collect and route precipitation away from the waste mass to minimize infiltration
The drainage layer in a final cover system rapidly conveys water that penetrates the vegetative layer away from the waste mass, protecting the low-permeability barrier.