Image via Wikipedia
Recycling urban wastewater and using it to grow food crops can help mitigate water scarcity problems and reduce water pollution, but the practice is not being as widely implemented as it should, according to a new UN food and agriculture organization (FAO) report . The FAO has called for governments to increase the amount of treated wastewater being used for irrigation purposes as this will reduce costs for farmers and cities and improved water quality.
The FAO report used case studies from Spain and Mexico to test methodologies for cost-benefit and cost-effective analyses of wastewater reuse projects. The Mexico case studies were drawn from three regions:
- Mexico City & Tula Valley
- Guanajuato City & La Purísima irrigation module
- Durango City & Guadalupe Victoria irrigation module
“The case studies in this report show that safely harnessing wastewater for food production can offer a way to mitigate competition between cities and agriculture for water in regions of growing water scarcity,” said Pasquale Steduto, Deputy Director of FAO’s Land and Water Division. “In the right settings, it can also help to deal with urban wastewater effluent and downstream pollution.”
 Winpenny, J. … [et al.] (2010). The wealth of waste : the economics of wastewater use in agriculture. (FAO water reports ; 35). Rome, Italy, Food and Agriculture Organization of the United Nations (FAO). xv, 129 p. Download full report
Source: FAO, 06 Sep 2010
Brazilian water companies that provide treated water for reuse are seeing numerous opportunities in these times of economic turbulence as they can attract big corporations by offering 30-50% cost reductions for services, the association of state sanitation companies Aesbe said in a release.
“Treated water for reuse costs about 8% of the conventional rate,” the president of São Paulo state water utility Sabesp, Gesner Oliveira, told BNamericas. “Treated water can be used to irrigate crops such as coffee and corn, to wash vehicles and streets, to fight fires, among other activities,” Oliveira added. In spite of the advantages, market estimates have shown that currently only 2% of companies reuse water in Brazil.
Only 50% of Sabesp’s treated water is being commercialized. “Our wastewater treatment plant has a capacity to produce 320,000m3/month of water for reuse. Of this total, approximately 160,000m3/m is being sold commercially,” Oliveira said.
Read more: BNamericas [subscription site], 05 Mar 2009
Peru’s government has declared a 60-day state of emergency in the sewerage system in capital Lima and neighboring Callao, to speed up repairs and new construction works. The executive decree will allow the La Perla pipeline to start operations, in spite of the local population’s protests; works to stabilise the retaining walls of the San Miguel pipeline; works to reduce the smell of the sewage; and once La Perla is working, authorities will close the interceptor norte pipeline for repairs. Additional works will include construction of a jetty to guide an underwater pipeline that will connect the San Miguel and La Perla ducts. The wastewater will receive biological pre-treatment before its disposal on the coast.
The emergency situation in Lima’s sewerage network was provoked by state-owned water utility Sedapal’s inability to prevent the collapse of the Costanero sewage pipeline, in San Miguel district, in February 2008. The pipeline channels sewage from almost 24 districts in Lima and, since its collapse, the sewage is being dumped directly onto the beach. Sedapal has been accused of poor management by spending money on badly planned new wastewater projects and did not investing in improving the treatment plants that were already in operation.
Earlier, the president of national environmental council Conam, Manuel Bernales, said that a remediation plan to solve the pollution of Lima’s coastal waters by untreated wastewater, required an investment of about US$ 1 billion. The plan would be based on the wastewater treatment and reuse of part of the treated effluent to irrigate public areas.
Sources: BNamericas (subscription site), 21 Apr 2008 ; BNamericas, 18 Apr 2008 ; Living in Peru, 21 Apr 2008