‘Wastewater can be very valuable’: the hydroponic system that provides clean water for Kenyans

Omiflo, a Nairobi startup, has developed a highly effective wastewater cleaning system. And it’s attractive to boot

At the Giraffe Centre in Nairobi, visitors can feed by hand pellets made from molasses to Africa’s tallest giants. It’s one of the area’s most popular tourist attractions and has played a pivotal role in conserving the critically endangered Rothschild giraffe. It’s fitting then that the centre is also home to another conservation project, one that’s preserving an increasingly scarce natural resource: water. 

“[The Giraffe Centre]It wanted something that was sustainable and suited its philosophy. It’s a really beautiful project and is saving them a lot of money too,” says Mshila Sio, who founded Kenyan startup Omiflo. The company installed a plant-based hydroponics system at the site to filter wastewater. This can be used for landscaping and flushing toilets. Omiflo was one of 16 winners in this year’s prestigious. No Waste ChallengeA competition that runs through international design organisations What Design Can Do

In Kenya, sanitation and access to clean drinking water are major challenges. According to Unicef,Only 29 percent of Kenyans have access the basic sanitation services, a number that has fallen by 5% from 2000. With the urban population expected to more than tripleBy 2050, from 12 million to 40 million, there are huge implications for water use and wastewater management across Kenya’s cities. Today, only 40 per cent of NairobiIt is connected to a sewage network. 

Design-driven innovations that change the world
The No Waste Challenge, a global design competition, addresses the negative effects of waste and consumerism on the environment
Check out the 16 winners

“Wastewater treatment is usually an afterthought,” Sio says about why he started the company. “The conventional technologies just don’t make sense for a developing country. They are too expensive, too complex, and require too much energy. They’re not fit for purpose.” 

In contrast, the Omiflo system doesn’t require any electricity, chemicals or significant gardening experience to build or maintain. TyphaCattail, also known as Cattail, is a plant that floats on top of a water body and absorbs oxygen from the air. The plants then inject it into the wastewater via their roots, creating beautiful natural spaces. The system is self-sustaining. The design is flexible and adaptable, so it can be used in many settings, from private homes and ecolodges to larger developments or municipalities. 

Mshila Sio, founder of Omiflo

Mshila Sio is the founder of Omiflo. Image by Khalid Amakran. Courtesy Of What Design Can Do

“Plants have been used to treat water for thousands of years,” says Sio. “The advantage of a floating system is that we use a much smaller space and eliminate the smell, the sludge – all of that ugly stuff. The installation cost is quite low and then operationally, you’re just looking after the plants. So, it’s very viable for low-income areas as well as high-income areas.” The water from an Omiflo system can also be drunk if a small chlorine dose is built in.

Sio was on holiday to Spain when the idea for the company was born. He came across Hydrolution, a startup that had developed a wastewater treatment method using plant-based technology. Sio spent years trying to get the solution to Nairobi. They lost touch around 2013 when Spain’s financial crash put Hydrolution out of business. Sio decided to take on the task. Omiflo’s first project rolled out in 2018 and the team has since installed 200 systems worldwide. 

“It took a few years to develop the technology and build a pilot to show how this works,” he says, adding that proof was necessary to secure investment. “We don’t have a culture of angel investors willing to try something new. Kenyans are skeptical. They want to feel, touch, and see. At the beginning, credibility was a major issue. We had to do quite a few projects before people said: ‘OK these guys know what they’re doing’.” 


The advantage of a floating system is that we use a much smaller space and eliminate the smell, the sludge – all of that ugly stuff

In the end, there were many sources of investment. Sio was one the recipients of a grant through President Obama’s Young African Leaders Initiative in 2014The Dutch ministry of foreign affairs provided additional funding, as well as donations from family and friends. Beyond the first pilots, that money also enabled Omiflo to build its own ‘biocentre’ in Nairobi. The intention was to have somewhere to grow the plants, showcase how the system works and carry out further research, but it’s become much more than that. 

“It’s a really cool place,” Sio enthuses. “People come and take a walk, they picnic there. We’ve transformed the ecosystem completely, just by recycling water. We find birds come in the morning, frogs … the whole area has been revived.” He readily admits that some residents living nearby were suspicious at first. “We went to all of our neighbours and said: ‘Can we have your sewage? Worst case scenario, we’ll plug you back into your septic tank and it’ll be like it was before’. We now produce about 2,000 litres of treated water every day.”  

Cattail plants are a great way to create a self-sustaining system for wastewater treatment. Image: Omiflo

In the future Sio hopes to build a country-wide system that provides a solution for the network of trucks that empty residents’ septic tanks. Sio says that while drivers are paid to haul the waste to a treatment facility, many dump it in nearby streams. Omiflo also received interest from Mexico and south-east Asia, where it is currently working with another What Design Can Do finalist. Eventually the team aims to develop a licensed solution that’s almost ‘plug and play’.

“We want to build models that can be duplicated everywhere,” Sio says. “We can only do so much work in Kenya, but the problem is prevalent throughout the developing world. I want to change the way people view wastewater. It’s not waste; it can be very valuable, even beautiful.”

Main image: Omiflo