CPWM Waste Treatment Technologies 3

Question 1

In a fluidized bed combustor treating municipal solid waste, what material is typically used as the bed medium?

Accepted Answer

Sand or limestone

Answer

Sand or limestone particles serve as the bed medium in fluidized bed combustors; limestone also helps neutralize acid gases formed during combustion.

Question 2

Which treatment technology is most appropriate for highly concentrated organic liquid hazardous wastes that are difficult to biodegrade?

Accepted Answer

High-temperature incineration

Answer

High-temperature incineration (>1200°C) destroys recalcitrant organic compounds through thermal oxidation, achieving destruction and removal efficiencies (DRE) of 99.99% or higher.

Question 3

What is the Destruction and Removal Efficiency (DRE) standard required by the US EPA for principal organic hazardous constituents (POHCs) in hazardous waste incinerators?

Accepted Answer

99.99%

Answer

EPA's RCRA regulations require hazardous waste incinerators to achieve a DRE of at least 99.99% (four nines) for each POHC listed in the waste feed.

Question 4

In composting, what is the ideal carbon-to-nitrogen (C:N) ratio for optimal microbial activity?

Accepted Answer

25:1 to 30:1

Answer

A C:N ratio of 25:1 to 30:1 provides optimal nutrient balance for microbial decomposition; ratios below 20:1 cause nitrogen loss as ammonia, while ratios above 40:1 slow decomposition.

Question 5

Which membrane technology is most commonly used in leachate treatment at modern landfills?

Accepted Answer

Reverse osmosis

Answer

Reverse osmosis uses semi-permeable membranes under high pressure to remove dissolved contaminants, heavy metals, and organics from landfill leachate, achieving high removal efficiencies.

(CPWM) Certified Professional in Waste Management Practice Test

(CPWM) Certified Professional in Waste Management Practice Test

CPWM Waste Treatment Technologies 3