Composting & Organics Recycling Flashcards
7 cards from real CRP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Composting & Organics Recycling flashcards as text
What temperature range must be maintained during the active composting phase to ensure pathogen destruction according to EPA standards?
Answer: 55–65°C (131–149°F)
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.
What is the recommended carbon-to-nitrogen (C:N) ratio for optimal composting?
Answer: 25:1 to 30:1
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.
Which composting technology uses enclosed, mechanically aerated vessels to control temperature, moisture, and odors?
Answer: In-vessel composting
In-vessel composting uses enclosed containers or tunnels with mechanical aeration controls, offering the greatest environmental control and odor management of all composting methods.
What is the primary distinction between aerobic and anaerobic composting processes?
Answer: Aerobic composting requires oxygen; anaerobic does not
Aerobic composting requires oxygen for microbial decomposition, while anaerobic composting occurs without oxygen and produces different byproducts, including methane and hydrogen sulfide.
Which of the following is classified as a 'brown' or carbon-rich feedstock in composting?
Answer: Dry leaves and wood chips
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.
What characteristic best indicates that compost has reached maturity and is considered 'finished'?
Answer: It is biologically stable with no further significant decomposition and has a soil-like odor
Finished or mature compost is characterized by biological stability (no further significant decomposition), a pleasant earthy odor, and absence of recognizable original feedstock materials.
Which EPA regulation under the Clean Water Act establishes standards governing the land application of biosolids used in composting programs?
Answer: EPA 40 CFR Part 503
EPA 40 CFR Part 503 establishes standards for the beneficial use and disposal of sewage sludge, including composted biosolids, covering pathogen reduction requirements and land application limits.