Water Scarcity
Your future food will be grown with wastewater
In an increasingly water-scarce world , there is no doubt that recycling water we ’ ve already used has to become normal . Part of that will inevitably mean using wastewater to help grow the food we need . But will we ever feel comfortable using waste water for food production ?
The reality is that this is already happening but more needs to be done to keep communities safe from the dangers of using untreated waste water .
The use of wastewater for food production is mainly a question of managing water shortage and socioeconomic costs . Exponential population growth and climate change have seriously compromised water availability in many regions , from the Middle East to Africa , Southeast Asia and Latin America . Local communities urgently need to find solutions to the problem of increasing water scarcity .
If used properly , waste water can provide important nutrients for plant growth and act as a replacement for mineral fertilizers . But it should be used for agricultural purposes only after being treated . Unfortunately , in many regions of the world , the reality is far from that .
Agricultural and water policies have not sufficiently addressed the inherent threats posed by the use of untreated waste water for irrigation . Often , hazardous materials in the form of heavy metals , organic contaminants , pathogens or antibiotic-resistant bacteria can be found in waste water . These accumulate in soils , crops and groundwater and so pass into the food chain . If evidence of the threats to human health and the environment are readily available , why are so many farmers still using untreated waste water for irrigation purposes ?
In developing countries , the use of untreated waste water has one big advantage : it is cost-free . This means farmers use it for irrigation of crops without taking the necessary precautions to avoid public health risks .
Greater water scarcity means more and more farmers will turn to waste water for irrigation . Siegfried Modola / Reuters
Today , waste water irrigates between 1.5 % and 6.6 % of farmland worldwide ; about 10 % of world ’ s food is produced using the practice . But the true extent of untreated waste water being used illegally for agriculture is unknown .
The Mezquital Valley in Mexico perfectly illustrates the issues involved . Rapid urbanization and inadequate treatment facilities have led farmers in the valley to use untreated waste water from Mexico City for irrigation purposes . For more than a century , this practice has helped grow marketable crops at low production costs . But these benefits come at the cost of the health of the population . The use of contaminated water for crops growth has resulted in severe gastrointestinal disease and cancer in the local community . Infants , young children , pregnant women , the elderly and people whose immune systems are compromised because of HIV / AIDS are especially vulnerable .
It is not a coincidence that the Mezquital Valley has the highest incidence of kidney cancer in the region as well as occurrence of helminth or Giardia infections in children . Farmers in the Mezquital Valley have been using waste
water for a century . Alextorrej , CC BY-SA
Only by developing eco-friendly sanitation strategies has the reduction of water pollution loads while conserving the benefits of nutrients been possible . Since 1999 , local waste-water plants have been built , and new wetlands have been constructed with satisfying results for water quality . But the people of the valley are still sceptical about the
32 Africa Water , Sanitation & Hygiene • May - June 2017