Hydraloop, the ingenious water reuse machine that French law blocks

French quality newspaper Les Echos is publishing a series called ‘Water in all its states – featuring solutions to improve access to the most precious resource.’

The first episode of the series features Hydraloop and our partner H2O Care.

In the premiere episode, a Dutch couple introduces an innovative device designed to repurpose water from showers and sinks for use in toilet tanks, reducing reliance on drinking water. This clever solution addresses the growing scarcity of water resources and offers an environmentally friendly approach to water management. However, the lack of subsidies currently makes this sustainable technology relatively expensive, limiting its accessibility despite its potential to make a significant impact.

This innovation highlights a broader issue: France reuses less than 1% of its treated wastewater, a strikingly low percentage. Treated wastewater, processed by treatment plants and typically returned to nature, could instead replace drinking water currently used for tasks like watering plants, irrigating fields, or flushing toilets. Other countries with fewer water resources have already embraced this approach. Italy reuses 8% of its treated wastewater, Spain 14%, and Israel an impressive 80%, proving that significant progress is both possible and necessary.

In France, mentalities are starting to change. The Water Plan, unveiled in 2023, plans to relax the regulations concerning the reuse of wastewater in order to standardize its exploitation. “But some decrees have still not been published,” regrets Tom Bobst, a young consultant in ecological transition, “such as the one that allows professionals welcoming the public, including hotels or campsites, to simply declare the reuse of wastewater rather than having to request, as today, an exemption from the prefecture and the regional health agency.” A situation that annoys this finder of environmental solutions, founder of the Viwable agency, whose mission is to help professionals limit their consumption of resources and energy.

One day, when a hotel called him to find a way to reuse its wastewater, Tom Bobst discovered Hydraloop, a device invented in 2015 by a Dutch couple, Arthur Valkieser and Sabine Stuiver, which allows wastewater to be treated and reused within a building, individual or collective. As a sign of seriousness, the machine is labeled Solar Impulse and won two awards at the prestigious Consumer Electronics Show (CES) innovation competition in Las Vegas. After successfully testing it at his customer’s site, Tom Bobst founded the company H2O Care in Azas (31) in 2022 to market Hydraloop devices in France.

Five water treatment systems

“The machine can only be connected to bathroom water, the bathtub and washbasin, and possibly condensation water from heat pumps or air conditioning,” says Tom Bobst. But we do not connect it to kitchen water, which is greasier, which requires filters and represents only 5% of a household’s consumption, nor, of course, to toilet water.” Behind its elaborately designed contours, Hydraloop is a real pocket wastewater treatment plant, combining five technologies to make shower water clean for reuse, all controlled by a central processor and monitored remotely.

Thanks to a sedimentation process, the heaviest particles fall to the bottom of the tank. By flotation, floating waste (hair, soap) passes through a skimmer or, for the smallest of them, is removed from the water by tiny air bubbles (dissolved air flotation). All this waste is sent to the wastewater network, to which the machine is connected. Once the water has been purified of its unwanted particles, it is treated in an anaerobic bioreactor, where a few moving microorganisms eject the bad bacteria behind a membrane, and then the water is finally disinfected by UV lamps. Without chemical injection, the purified water is stored within the device and then sent when necessary by a pump system to the toilet or washing machine. Of course, the device is also connected to the conventional drinking water network to cope with a peak in demand and not leave the user dry.

There are two versions of the Hydraloop machine: the H300, the size of a small fridge and with a capacity of 300 litres, is intended for individuals and can handle grey water treatment in five bathrooms, while the H600, the size of an American fridge and with a volume of 600 litres, can ensure the purification of a dozen bathrooms and be installed in series to increase its capacity. All this for an estimated electricity consumption of between 0.8 and 1 kWh per day and per appliance, which is a little less than the above-mentioned fridges (332 kWh per year on average).

25% to 40% reduction in water consumption

The devices are manufactured in the Netherlands, from mainly European materials. They are made of a single type of plastic, which makes them easier to recycle. Only the microprocessors, which automatically control the machine and allow customers to monitor their wastewater consumption, come from China.

Installing the machine is not particularly difficult “and does not require more than a morning of training for plumbers,” says Tom Bobst. H2O Care has thus formed a partnership with about thirty professionals in France. Maintenance, too, is not very heavy. “All you have to do is pour 1 liter of white vinegar every year to power the device’s self-cleaning system, change the UV lamp every four to five years, and the pump every ten to fifteen years,” says the founder of the start-up.

In France, H2O Care, which has exclusive commercial rights in the west of the country, has installed its devices in the homes of about twenty individuals – not subject to wastewater regulations – and three in the homes of courageous professionals who have made the derogatory procedure with the authorities. About thirty projects are underway. Worldwide, more than 1,000 devices have been installed by Hydraloop’s 135 partners. And the device has already proven its usefulness, allowing between 25% and 40% water savings in the buildings that have installed it. But its deployment is hampered by its cost and still uncertain regulations.

6,000 euros for a device

The H300, intended for individuals, is available at a cost of 6,000 euros, including transport and installation. The return on investment is made in about fifteen years. A price that can remain a deterrent for households. For professionals, on the other hand, the operation is slightly more interesting, the H600 costing 8,500 euros each and can pay for itself in five to ten years.

“There are a number of factors behind this cost,” says Bobst. First, the price of water in France is low, which increases the duration of the return on investment. Secondly, the device is not yet subsidised, we will have to wait for the decrees for public funding to be possible. Finally, there is the issue of water networks in buildings. Indeed, the overwhelming majority of homes in France are designed around a single network carrying drinking water. To implement the Hydraloop solution, a second wastewater network must therefore be created from scratch, resulting in additional work and costs.

For this reason, H2O Care advises for the moment to install its machines only in the case of renovation or new construction, in order to limit costs. In the meantime, Tom Bobst is campaigning to include in the new energy and environmental regulations governing new construction, the RE2020, an incentive or an obligation to install a double network in new buildings to receive grey water and thus facilitate its reuse. Because if the technology is perfect, it seems that we are not quite ready to welcome it yet.

This article is an English translation of the French original, written by Pierre Foutin, published by Les Echos on July 30, 2024. The copywright of this article lies entirely with Les Echos.

Disclaimer: Some information in the article is incorrectly portrayed or outdated since the interview.

Here are the necessary amendments:
• The article states that ‘some decrees have still not been published’. However, a new decree on greywater use was issued in July 2024, now allowing greywater recycling in places like campgrounds, hotels, and gyms.
• There are not five but six treatment technologies: sedimentation, flotation, air flotation, foam fractionation, an aerobic bioreactor, and UV disinfection.
• The article mentions that ‘bad bacteria are ejected behind a membrane’. This is incorrect. Hydraloop is unique because it does not use any filters or membranes.
• The reusable water is described as being ‘sent by a pump system to the toilet or washing machine’. Additionally, this water can also be used for garden irrigation and swimming pools.
• The article states there are two versions of the Hydraloop: the H300 and H600. This is incomplete. There are four versions: Hydraloop H300, H600, Cascade (modular, scalable and made to measure), and Concealed (integrated with the toilet flushing system).
• The microprocessors are said to come from China. In reality, the design and software are developed by Hydraloop and are our property. Only the PCB board itself is manufactured in China.
• The cost mentioned pertains to our French partner. Pricing may vary in other countries.