The ₹1,500 Waste Audit
Over one month the 40-member Eco Club of a government school in Madurai audits everything the school throws away: 12 kg of paper, 19 kg of plastic water bottles (roughly 950 bottles), 30 kg of food waste from the canteen, and 3 kg of broken chargers and bulbs. The school burns the whole pile behind the playground every Friday. A scrap dealer offers ₹12 per kg for clean, dry plastic bottles and ₹8 per kg for paper, but rejects any sack that contains food or wet waste. Two segregation bins cost ₹900, a wire compost ring costs ₹1,200, gloves and sacks cost ₹300, and the club has exactly ₹1,500 with one month to act. The canteen manager says he will buy compost at ₹10 per kg if it is ready in 45 days.
1. Classify the four waste streams, identify the largest by weight, and compute the potential monthly income from selling recyclables.
Read the worked answer
Biodegradable: paper (12 kg) and food waste (30 kg). Non-biodegradable: plastic bottles (19 kg) and broken chargers and bulbs (3 kg), the latter also hazardous when burned.
Largest by weight is food waste, 30 kg - the stream nobody is watching, and the one that contaminates everything it touches.
Income at the dealer's rates: bottles 19 × ₹12 = ₹228; paper 12 × ₹8 = ₹96; total ₹324 a month. But the condition attached matters more than the amount: dry and separated, with no food or wet waste, or the sack is rejected. Today's single pile means even the sellable 31 kg is contaminated, so the ₹324 is lost while the school still pays the cost of burning. The finding is not 'we could earn ₹324'; it is 'we are destroying ₹324 every month'.
2. Allocate the ₹1,500 using the waste hierarchy. Justify why you exclude at least one option and include another.
Read the worked answer
Buy the two bins (₹900) and gloves and sacks (₹300) - ₹1,200 spent, ₹300 held in reserve. The bins are what convert the ₹324 of waste into income, and no cheaper item can replace them.
Exclude the ₹1,200 compost ring and build one from scrap wire mesh with donated labour instead; the canteen already supplies 30 kg a month and the manager will buy compost at ₹10 per kg, so the ring is worth having but not worth paying full price for when the budget is this tight.
The hierarchy drives the order. First reduce: 950 bottles a month is a design problem, so ask students to bring steel bottles and install a corridor dispenser - that removes weight before anyone has to handle it. Then reuse sacks and bins, then recycle through the dealer, and compost only what remains. Recycling is third, not first, because reduction is cheaper and starts earlier.
3. Explain the environmental harm of the Friday fire, and propose one school policy with a measurable check.
Read the worked answer
Open burning of mixed waste releases carbon monoxide, fine particulates and dioxins, and the chlorinated plastic and PVC-coated wire in the 3 kg of e-waste make the fire considerably worse than a paper fire would be. The ash left on the ground concentrates heavy metals, and it sits where children play, so the exposure is not theoretical.
A workable policy: a written 'no burning' rule, with segregated waste handed to the dealer and to the panchayat collection, a segregation point at the canteen, and a monthly weighing of each stream displayed on a noticeboard. The weighing is the important half - it shows whether the 950 bottles and 12 kg of paper are actually falling, or whether the policy exists only on paper. A green policy without a number attached is a slogan.