CRP Composting & Organics Recycling

Question 1

What temperature range must be maintained during the active composting phase to ensure pathogen destruction according to EPA standards?

Accepted Answer

55–65°C (131–149°F)

Answer

EPA requires temperatures of 55–65°C (131–149°F) to be maintained for a specified duration to kill pathogens and weed seeds in compost.

Question 2

What is the recommended carbon-to-nitrogen (C:N) ratio for optimal composting?

Accepted Answer

25:1 to 30:1

Answer

A C:N ratio of 25:1 to 30:1 provides the optimal balance of carbon for microbial energy and nitrogen for microbial protein synthesis during active decomposition.

Question 3

Which composting technology uses enclosed, mechanically aerated vessels to control temperature, moisture, and odors?

Accepted Answer

In-vessel composting

Answer

In-vessel composting uses enclosed containers or tunnels with mechanical aeration controls, offering the greatest environmental control and odor management of all composting methods.

Question 4

What is the primary distinction between aerobic and anaerobic composting processes?

Accepted Answer

Aerobic composting requires oxygen; anaerobic does not

Answer

Aerobic composting requires oxygen for microbial decomposition, while anaerobic composting occurs without oxygen and produces different byproducts, including methane and hydrogen sulfide.

Question 5

Which of the following is classified as a 'brown' or carbon-rich feedstock in composting?

Accepted Answer

Dry leaves and wood chips

Answer

Dry leaves and wood chips are carbon-rich 'brown' materials that provide structure and balance the nitrogen found in 'green' feedstocks such as food scraps and fresh grass clippings.

CRP - Certified Recycling Professional Practice Test

CRP - Certified Recycling Professional Practice Test

CRP Composting & Organics Recycling