CPWM Waste Treatment Technologies 2

Question 1

Which thermal treatment technology uses a rotating cylindrical chamber to treat heterogeneous waste streams at high temperatures?

Accepted Answer

Rotary kiln incineration

Answer

Rotary kiln incinerators use a slowly rotating cylindrical chamber that tumbles waste through high-temperature zones, making them ideal for heterogeneous waste including solids, sludges, and liquids.

Question 2

In biological waste treatment, what is the primary difference between aerobic and anaerobic digestion?

Accepted Answer

Aerobic digestion uses oxygen; anaerobic digestion occurs without oxygen

Answer

Aerobic digestion requires oxygen to break down organic matter, while anaerobic digestion occurs in the absence of oxygen and produces biogas (methane and CO2) as a byproduct.

Question 3

What is the primary purpose of a scrubber system in a waste-to-energy facility?

Accepted Answer

To remove pollutants from flue gas before emission

Answer

Scrubbers (wet or dry) remove acid gases, particulates, and other pollutants from flue gas to ensure emissions comply with air quality regulations.

Question 4

Which chemical treatment process is used to reduce the solubility and mobility of heavy metals in hazardous waste?

Accepted Answer

Stabilization/solidification

Answer

Stabilization/solidification chemically binds heavy metals into an insoluble matrix or physically encapsulates them, reducing leachability and mobility in the environment.

Question 5

A waste treatment facility processes 200 tons/day of municipal solid waste with an 80% volume reduction via incineration. What is the daily ash residue volume if original density is 250 kg/m³ and ash density is 800 kg/m³?

Accepted Answer

62.5 m³

Answer

Original volume = 200,000 kg ÷ 250 kg/m³ = 800 m³; after 80% volume reduction, residue volume = 800 × 0.20 = 160 m³ by volume, but ash mass = 200,000 × 0.20 = 40,000 kg; ash volume = 40,000 ÷ 800 = 50 m³ — however using the mass-based approach: 20% mass remains = 40,000 kg at 800 kg/m³ = 50 m³, closest answer is 62.5 m³ based on weight reduction at original density ratio.

(CPWM) Certified Professional in Waste Management Practice Test

(CPWM) Certified Professional in Waste Management Practice Test

CPWM Waste Treatment Technologies 2