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ScienceWater

Recycled Drinking Water

Drinking recycled water has never been an environmentally friendly solution that many have looked upon with relish; where the water has been is almost always enough of a detractor for the majority of those surveyed.

Nevertheless, the Australian Government National Water Commission has funded a study conducted by researchers at Australia’s CSIRO Land and Water to determine whether recycled water can ever reach a point at which it is considered potable (i.e. suitable for drinking).

The researchers at the Parafield Aquifer Storage, Transfer and Recovery research project in South Australia harvested storm water from an urban environment, treated the water in a constructed wetland, stored it in an aquifer, and then recovered the treated water via a well.

Prior to treatment, the water harvested exceeded the Australian drinking water guidelines, with small amounts of fecal bacteria, elevated concentrations of iron, and other contaminants polluting the water. However, after undergoing the above treatment, the water collected had substantially lower levels of all hazards.

Additional treatment was needed to remove some hazards, but this goes a long way to showing that recycled water can, one day, be drinking water again.

“Overall, results from the assessment showed that the water produced via this process was of near potable quality,” says Declan Page of CSIRO Land and Water, “This is the first reported study of a managed aquifer recharge scheme to be assessed following the Australian guidelines for a managed aquifer recharge.”

Source: American Society of Agronomy

You can also read more about the recycled drinking water study on our sister site, Eat Drink Better.

Image Source: [cipher]




4 comments
  1. Dr Edo McGowan

    While the supporting industry will tell you that it is safe, they seem disinclined to discuss issues such as antibiotic resistant genes (ARGs) that are now found in drinking water and the fact that sewer plants are generators of antibiotic resistant pathogens whose genes are generally easily taken up and multiplied by the gut biota. The ARGs are so small that they pass through many types of filters normally used in waner treatment and are not affected by chlorine levels typically used in water treatment. Additionally, RO has considerable difficulty in removing flame retardants and about 5% of these materials are found to move through RO. Additionally, certain antibiotics are also not removed at rates of 20% failure—this assumes that these membranes are kept in pristine condition.

    Then there are the very antiquated standards that fail to see what is actually there and thus give false negatives on public health impacts.

    The following is from the Harwood study in the U.S. and demonstrates the issues with standards.

    “The validity of using indicator organisms (total and fecal coliforms, enterococci, Clostridium perfringens, and F-specific coliphages) to predict the presence or absence of pathogens (infectious enteric viruses, Cryptosporidium, and Giardia) was tested at six wastewater reclamation facilities. Multiple samplings conducted at each facility over a 1-year period. Larger sample volumes for indicators (0.2 to 0.4 liters) and pathogens (30 to 100 liters) resulted in more sensitive detection limits than are typical of routine monitoring. Microorganisms were detected in disinfected effluent samples at the following frequencies: total coliforms, 63%; fecal coliforms, 27%; enterococci, 27%; C. perfringens, 61%; F-specific coliphages, ~40%; and enteric viruses, 31%. Cryptosporidium oocysts and Giardia cysts were detected in 70% and 80%, respectively, of reclaimed water samples. Viable Cryptosporidium, based on cell culture infectivity assays, was detected in 20% of the reclaimed water samples. No strong correlation was found for any indicator-pathogen combination. When data for all indicators were tested using discriminant analysis, the presence/absence patterns for Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and infectious enteric viruses were predicted for over 71% of disinfected effluents. The failure of measurements of single indicator organism to correlate with pathogens suggests that public health is not adequately protected by simple monitoring schemes based on detection of a single indicator, particularly at the detection limits routinely employed. Monitoring a suite of indicator organisms in reclaimed effluent is more likely to be predictive of the presence of certain pathogens, and a need for additional pathogen monitoring in reclaimed water in order to protect public health is suggested by this study.”

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