Dear friends of Peru Permaculture, of water, and of life:
Pure water from the Pumahuanca River
Sad to say, a few years ago there was a cholera outbreak in Peru which resulted in an estimated loss of tourism amounting to three times the expenditure on water and sanitation for the entire country over the preceding ten years.
In the Sacred Valley of Peru, all the sewage and industrial wastes of Cusco flow untreated via the Huatanay River directly into the Vilcanota, or "Sacred River." Add to that the sewage of the valley's cities and towns from Pisac to Aguas Calientes. This is the same river that wraps around the base of Machu Picchu. All fish have disappeared from the contaminated water. And yet, unwary tourists still take rafting trips on this running sewer. Some residents use the water for irrigating crops and even for washing clothing. Periodic flooding spreads the contamination over parts of the towns.
What can be done to restore the river? The local municipal governments say they are awaiting funding for a "Plan Maestro" (master plan) to treat the sewage, but no-one knows how long this may take; local residents have little faith in the government, saying that the money rarely goes for needed projects.
Sewage treatment systems for developing countries need not be prohibitively expensive or high tech.
1) Wastewater stabilization ponds (WSP) and constructed wetlands, cost less than chemical disinf ection but need land; good for hotels, schools. They decrease biological oxygen demand (BOD) by 90%, nitrogen by 70%, phosphorus by 30-45%, lower coliforms by over 99%, and helminths 100%. WSPs need 10-25 day retention time, depending on ambient temperature. Sun kills pathogens.
2) Free Water Surface Wetlands (FWS): Low cost, low energy, close to site, resulting water is OK for agriculture & aquaculture. Water hyacinths in shallow ponds used in Senegal remove heavy metals. Water hyacinth lowers BOD & nutrients, works better than WSP for this. But WSP removes pathogens better. Duckweed can also grow readily on the surface, but wastewater must be free of heavy metals if duckweed is to be used as animal feed. Duckweed has similar protein to soybeans. Remove 50% of duckweed daily. It suppresses mosquitoes. The treated wastewater can irrigate parks, trees, agriculture, or be used for aquaculture or toilet flushing. Bangladesh PRISM used duckweed to treat ½ million liters of raw sewage from a hospital. First, the wastewater went to a WSP pond for 24 hours, then a plug-flow system, duckweed, finally 3 fish ponds, where no pathogens were found.
(Source: Community-Based Technologies for Domestic Wastewater Treatment & Re-use: Options for Urban Agriculture)
Please go to this link to learn about some of John Todd's (inventor of Living Machines) ecological ways to purify wastewater to an advanced standard: http://www.sciencedirect.com/science/article/pii/S0925857403000648
Briefly, the article describes Advanced Ecologically Engineered Systems (AEES) for treatment of sewage in cold temperatures (Vermont winter), 300 cubic meters a day; the Restorer, powered by wind and solar energy, was able to treat a pond polluted with toxic leachate, 295 cu. meters/d; a third treated 37,850 cubic meters a day of poultry plant waste, saving them 74% of their previous energy requirement.
In the Sacred Valley of Peru, all the sewage and industrial wastes of Cusco flow untreated via the Huatanay River directly into the Vilcanota, or "Sacred River." Add to that the sewage of the valley's cities and towns from Pisac to Aguas Calientes. This is the same river that wraps around the base of Machu Picchu. All fish have disappeared from the contaminated water. And yet, unwary tourists still take rafting trips on this running sewer. Some residents use the water for irrigating crops and even for washing clothing. Periodic flooding spreads the contamination over parts of the towns.
What can be done to restore the river? The local municipal governments say they are awaiting funding for a "Plan Maestro" (master plan) to treat the sewage, but no-one knows how long this may take; local residents have little faith in the government, saying that the money rarely goes for needed projects.
Sewage treatment systems for developing countries need not be prohibitively expensive or high tech.
1) Wastewater stabilization ponds (WSP) and constructed wetlands, cost less than chemical disinf ection but need land; good for hotels, schools. They decrease biological oxygen demand (BOD) by 90%, nitrogen by 70%, phosphorus by 30-45%, lower coliforms by over 99%, and helminths 100%. WSPs need 10-25 day retention time, depending on ambient temperature. Sun kills pathogens.
2) Free Water Surface Wetlands (FWS): Low cost, low energy, close to site, resulting water is OK for agriculture & aquaculture. Water hyacinths in shallow ponds used in Senegal remove heavy metals. Water hyacinth lowers BOD & nutrients, works better than WSP for this. But WSP removes pathogens better. Duckweed can also grow readily on the surface, but wastewater must be free of heavy metals if duckweed is to be used as animal feed. Duckweed has similar protein to soybeans. Remove 50% of duckweed daily. It suppresses mosquitoes. The treated wastewater can irrigate parks, trees, agriculture, or be used for aquaculture or toilet flushing. Bangladesh PRISM used duckweed to treat ½ million liters of raw sewage from a hospital. First, the wastewater went to a WSP pond for 24 hours, then a plug-flow system, duckweed, finally 3 fish ponds, where no pathogens were found.
(Source: Community-Based Technologies for Domestic Wastewater Treatment & Re-use: Options for Urban Agriculture)
Please go to this link to learn about some of John Todd's (inventor of Living Machines) ecological ways to purify wastewater to an advanced standard: http://www.sciencedirect.com/science/article/pii/S0925857403000648
Briefly, the article describes Advanced Ecologically Engineered Systems (AEES) for treatment of sewage in cold temperatures (Vermont winter), 300 cubic meters a day; the Restorer, powered by wind and solar energy, was able to treat a pond polluted with toxic leachate, 295 cu. meters/d; a third treated 37,850 cubic meters a day of poultry plant waste, saving them 74% of their previous energy requirement.