Long abandoned to the shadows of architectural thinking, the proverbial "throne" of the house – the toilet – is beginning to make a bit of a comeback, taking a central role in last year's Venice Biennial, and making an occasional appearance in Archinect features. While it may upset our lingering Victorian sensibilities, toilets – and what they flush – are an integral aspect of the contemporary house and the modern city. In the context of a drought crisis, these water-vaccuums take on a different hue. The "Growing Energy from Waste: a natural twist on Direct Potable Reuse" Honorable Mention submission reexamines the toilet and its contents within a larger framework, proposing using existing algae technology to treat our wastewater.

Growing Energy from Waste: a natural twist on Direct Potable Reuse, by Prentiss Darden and Algae Systems LLC

In Southern California, we fill our toilets with water that has traveled over 400 miles, consuming great amounts of energy and emitting carbon dioxide in the process, to flush it down the toilet and into the ocean. Each day, 1.35 billions of gallons of treated wastewater in California is discharged to the ocean, a waste of three valuable resources: water, nutrients, and energy (Heal the Bay). In a time of extreme drought, we move water hundreds of miles from the Tuolumne, Mokulmne, and Colorado River watersheds to our most populous areas: the San Francisco Bay, San Jose, Los Angeles County, and San Diego County.

The State Water Project uses 2-3% of all energy consumed in the state to move water. For every acre foot of water (approx 325,000 gallons), 3,000 kWh of energy is needed to bring water from the Bay Delta to Southern California and 2,000 kWh per acre ft from the Colorado River. Taxing the Colorado River 1.6 trillion gallons per year, we expend 10,000 Megawatt hours of energy and emit tons of carbon dioxide bringing water to Southern California. Moving and treating water and wastewater throughout our state has significant energy costs and climatic impacts that worsen the trends towards altering precipitation patterns that affect the availability of water resources. Sea levels are rising, and critical infrastructure, such as wastewater treatment plants, generally sited adjacent to waterbodies, are vulnerable to rising waters. Once we use the water and discharge it into waterways, the nutrients in the effluent create algal blooms and dead zones, damaging aquatic habitat. Overall, we’re in quite a lot of trouble. 

We’re long overdue to evolve our water use and wastewater treatment infrastructure, and while we’ve made progress, there is still work to do as well as opportunity to engage new systems and new thinking to implement regenerative practices into wastewater treatment. There has been quite a bit of progress in California in recycling water to Title 22 standards, installing purple pipe networks for distribution, and building advanced water treatment facilities. We’re on the verge of code and regulations that will allow us to consume wastewater treated to potable water quality standards. Many are working hard across the state to create this reality and progress is to be celebrated. However, one of the greatest drawbacks of direct potable reuse, is the energy consumption it requires to bring water to potable quality. 

What if, we treat our wastewater in a way that generates surplus energy, without emitting additional levels of carbon dioxide? This way, we would be able to practice direct potable reuse, without consuming large amounts of energy, which in turn, if it is derived from thermoelectric sources, consumes water in its own production. Is this possible? Yes, we can do this. Using a system with roots at NASA and initial funding from Google Green, Algae Systems LLC has evolved its technology and expanded its operational protocol over the past 8 years to treat wastewater while also creating algae fuel, electricity, and fertilizers. Since 2012, a demonstration plant in Mobile Bay, Alabama has successfully treated 40,000 gallons per day from the Daphne Municipal Utility, using one-third the energy of a typical wastewater treatment plant, producing water quality that exceeds regulatory standards, and producing ASTM-grade diesel and Class A biosolids. 

By inserting Algae Systems’ technological choreography into the treatment train of direct potable reuse, we can go beyond a reduced negative impact to a regenerative, beneficial impact. This technology can be bolted on to existing wastewater treatment plants, building in resiliency, replacing crumbling, outdated structures over time. In the words of Buckminster Fuller, “you never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.” This is the opportunity that Algae Systems provides.

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From the judges:

"This really does offer an alternative to the effluent issue. I'll drink the Kool aid even is it is toilet to tap..." – Charles Andersen, President of WERK

Check out the image gallery for Growing Energy from Waste's complete presentation.

Click here to see the other winners in both the Pragmatic and Speculative categories!