Some 380 billion cubic meters (1 m3 = 1000 litres) of wastewater are produced annually worldwide — five times the amount of water passing over Niagara Falls annually. That’s enough to fill Africa’s Lake Victoria in roughly seven years, Lake Ontario in four.
Furthermore, wastewater volumes are increasing quickly, with a projected rise of roughly 24% by 2030, 51% by 2050.
Looked at another way, the volume of wastewater roughly equals the annual discharge from the Ganges River in India. By the mid-2030s, it will roughly equal the annual volume flowing through the St. Lawrence River, which drains North America’s five Great Lakes.