- Water scarcity. About 3 billion people are affected by water scarcity caused by diminishing reserves of freshwater (excessive use), climate change (drought, extreme climatic events, vanishing snow caps…)
- Excessive volumes of wastewater produced by growing urban population
- Increased demand for crops to feed growing urban population
The “Quick Fix!”
Irrigating urban agricultural land with untreated wastewater!
A possible outcome:
Spread of pandemic diseases leading to large scale collapse
A new 53-city study conducted by the International Water Management Institute (IWMI) reveals that about 80 percent of the cities studied use untreated or partially diluted wastewater for agriculture. At least 50 percent of the urban agricultural land in those cities is irrigated with raw or diluted wastewater.
“Irrigating with wastewater isn’t a rare practice limited to a few of the poorest countries. It’s a widespread phenomenon, occurring on 20 million hectares across the developing world, especially in Asian countries, like China, India and Vietnam, but also around nearly every city of sub-Saharan Africa and in many Latin American cities as well,” said IWMI researcher Liqa Raschid-Sally.
“It’s a widespread phenomenon, occurring on 20 million hectares (50 million acres) across the developing world, especially in Asian countries, like China, India and Vietnam, but also around nearly every city of sub-Saharan Africa and in many Latin American cities as well.”
Wastewater is most commonly used to produce vegetables and cereals, especially rice, pose a health threat to the farmers as well as the consumers.
“The negative and positive implications of wastewater agriculture have only recently received attention. This study offers the first comprehensive, cross-country analysis of the conditions that account for the practice and the difficult tradeoffs that arise from it,” said Colin Chartres, director general of IWMI.
About 200,000 people in Accra, 10 percent of the urban population of Ghana’s capital city, consume vegetables produced on just 100 hectares of urban agricultural land, which is irrigated with wastewater, according to the IWMI report. “That gives you an idea of the large potential of wastewater agriculture for both helping and hurting great numbers of urban consumers.” Raschid-Sally said.
“And it isn’t just affluent consumers of exotic vegetables whose welfare is at stake. Poor consumers of inexpensive street food also depend on urban agriculture.” She reported.