Only 10% of people on Earth have access to safe water, says the Water Organization, a nonprofit headquartered in Chennai, India. That means 90% may have to drink foul water, at a vast cost to their health. One obstacle to resolving the problem is that two key technologies, wastewater treatment and desalination, are very expensive, and very heavy on energy use. Now an Israeli company says it has a low-cost, energy-positive solution, notably appropriate for the capital-poor developing world – merely by adding aquatic weeds to the equation.

The main cost in wastewater treatment is the energy needed to oxygenate the wastewater for the bacteria breaking down the goo to breathe. Wastewater treatment alone accounts for up to 4% of total electricity usage in the United States.

By introducing algae into the water-treatment equation, and, crucially, sequestering the delicate microplants from the bacteria that actually clean our waste, Aquanos claims to have reduced the energy cost of water treatment by 70% to 90%.

It gets better: the system is a net generator of energy, in the form of biogas (methane), which can be used for power generation, says company co-founder and CEO Udi Leshem. And existing wastewater treatment plants can be retrofitted to use the Aquanos algal system, the company says.

The system is useful in areas that lack reliable or enough electricity to run conventional wastewater treatment plants, says the company, which has started to sell its systems in Israel and around the world, too. Though none are operational yet: these things take time to build, Leshem points out.

First breathe in

The Aquanos method consists of two basic stages. The first is a preliminary breakdown by anaerobic bacteria (who don't need oxygen). This stage produces water for the next stage of treatment, and the methane gas we mentioned, which can be sold as an energy source.

The second stage begins when this water, partially-cleaned by the anaerobic germs, passes to the aerobic bacteria, who start to break it down some more, bless them, breathing oxygen produced by the algae. (Which are breathing the carbon dioxide produced by the bacteria. It's a beautiful circle.)

The product of this process is water clean enough for agriculture, but not for drinking.

It would be clean enough for drinking if people weren't so fussy, Leshem indicates. But many cringe at the thought of drinking treated toilet water and there is, ultimately, some risk that despite all that loving microbial attention, the treated water will have trace heavy metals, pathogens or something else that we don't want to imbibe.

next previous 4 of 4 | The Aquanos water treatment system. Credit: Courtesy of Aquanos 1 of 4 | The Aquanos water treatment system, installed at a kibbutz. Credit: Courtesy of Aquanos 2 of 4 | Breeding the algae for use in the Aquanos water treatment system. Credit: Courtesy of Aquanos

Leshem points out that almost all clean water in the world is used for agriculture, anyway, not for drinking – that's around 10% of the use. It's better to generate a critical mass of water for cultivation than for drinking, in his view.

In a final upside of the Israeli startup's system, when the algae pass onto the great void, it can be dried out and sold as fertilizer, as feedstock for plastics, and so on.

What makes this Israeli startup's treatment-by-algae better than other treatment-by-algae companies? It lowered costs by 90%, explains Leshem, by segregating the algae and bacteria. The algae live in shallow reactors called raceways, for some reason.

Open gallery view The Aquanos process: Wastewater is given to anaerobic germs, which start the cleaning process; the water then passes to aerobic bacteria - which are fed oxygen by algae. Credit: Aquanos and Haaretz

When the algae and bacteria live together, the bacteria may proliferate and make the water murky, blocking the sunlight the algae need for photosynthesis. Separate living arrangements for the two beings also makes it easier to maintain optimal conditions for each.

Low cost is crucial to the developing world, which has its troubles. “Untreated wastewater in the developing world kills more people than wars, car accidents, HIV and malaria combined," Leshem claims.

After developing a small-scale, self-funded pilot project, the company, which was founded in 2011, raised seed money and began beta testing in central Israel. The testing continues while Aquanos builds those facilities that it has sold. It expects the systems to start actual production in early 2016, Leshem says.

Theoretically, Aquanos’s technology could be scaled up indefinitely, but the company sees its main market in the developing world. Meanwhile, it has sold a facility to three kibbutzim in the Golan Heights, where it will serve the needs of 2,400 people. That system will process 400 cubic meters a day. One cubic meter is equivalent to 600 bottles of mineral water. It is also the amount of wastewater that six people produce in a day.

But they say are also currently in BOT (build, operate, transfer) negotiations to install a system for a city in the Ivory Coast with a population of 600,000. The government would take over the facility from the company in 2035, according to the projection.

Aquanos has only seven employees, of whom two are part time. To date it has raised about $2 million from private and strategic investors, including World Water Works, a U.S.-based manufacturer of waste water treatment equipment, and the Dutch company Fortuna Holdings. And just last week, the company could proudly announce winning the Cleanvest Cup at the WATEC 2015 conference in Tel Aviv for "best innovative company", by virtue of its ability to produce clean water and energy too.