In the last blog I showed what reclaimed wastewater could do for an ecosystem. Very cool. But what about for drinking water. I actually was involved in an indirect potable reuse project several years ago. The concept was to take wastewater, filter it with sand filters, filter it with microfiltration, reverse osmosis and then hydrogen peroxide and ultraviolet light. This is what they do in Orange County California when they recharge groundwater, and have been for over 30 years. Epidemiological studies in the 1990s indicated no increased incidence of disease when that water was withdrawn from the aquifer, and then treated in a drinking water plant before distribution. So our project was similar – recharge to the Biscayne aquifer in south Florida. It worked for us. Total phosphorous was below 10 ppb, TDS was less than 3 mg/L (<1 after RO), and we were able to show 3 log removal of endocrine disruption compounds an d pharmaceuticals. It worked well. This is a concept in practice in California. And will be at some point in south Florida since only the Biscayne aquifer provides sustainable water supplies. Here is what our system looked like.
This is also the same basic concept Big Springs Texas uses for their direct potable program, demonstrating that the technology is present to treat the water. A means for continuous monitoring is lacking, but Orange County demonstrates that for indirect potable reuse projects, a well operated plant will not risk the public health. This is how we do it safely.