Luong Thi Huyen makes a living out of recycling what others discard. The 55-year-old earns about 100,000 dong (US$4.31) a day in the Vietnamese capital of Hanoi collecting and sorting a wide variety of waste by hand.“I buy from established sources like shops and restaurants. Cardboard boxes, plastic, iron, whatever they have I will buy,” said Huyen, who migrated from the northern province of Hung Yen in 2010 so she could support her son through university by picking and sorting trash.Huyen is…