Explain the market and contamination limits on municipal recycling, describe composting as a managed biological process, and correctly sort household items into their proper waste-management category.
Recycling is not automatic or free -- it depends on there being a buyer willing to pay for the sorted, cleaned material, and on keeping contamination low, since even a modest fraction of contaminated items (food-soiled containers, wrong plastic types) can cause an entire load to be rejected and sent to a landfill instead. Plastic recycling specifically is more limited than many people assume: plastics carry numbered resin codes 1 through 7, but in most municipal systems, only a subset -- mainly type 1 (PET) and type 2 (HDPE) -- are widely and economically recycled in practice, while others are technically recyclable but rarely actually processed for cost and market reasons. This is a documented limitation worth knowing accurately, not a reason to stop recycling altogether.
Composting is a managed AEROBIC (oxygen-requiring) decomposition process that converts food and yard waste into a nutrient-rich soil amendment; it needs a working balance of "browns" (dry, carbon-rich material like dead leaves or cardboard) and "greens" (nitrogen-rich material like food scraps or grass clippings), along with moisture and periodic turning for aeration, or the pile turns anaerobic (low-oxygen) and smelly instead. Household hazardous waste -- paints, solvents, batteries, pesticides -- requires special collection separate from regular trash, since these materials can leach toxic substances; electronic waste (e-waste) is a fast-growing category containing both valuable recoverable materials (gold, copper, rare earth elements) and hazardous ones (lead, mercury, cadmium). The federal Superfund program (the Comprehensive Environmental Response, Compensation, and Liability Act of 1980) is the US EPA's program for identifying and cleaning up the country's most seriously contaminated hazardous waste sites.
Mastery looks like: They can explain why a recyclable item may not actually be recycled in practice, correctly identify the two most reliably recycled plastic types, and sort household items into the correct disposal category.
Common stumbles: Assuming every numbered plastic symbol guarantees the item will be recycled; letting a compost pile go anaerobic by skipping aeration or the browns-and-greens balance.