Given the nature of her quest, it is just as well that Virginia Gardiner has never been too self-conscious about bodily functions and their taboos.
In her mission to create a waterless loo that uses no energy and turns the waste into a useable product, Gardiner has exhibited a bowl moulded from horse manure and monitored the activity of composting worms in her bathroom, turning "poop" into fertile soil, she said.
Now, seven years after she embarked on her plan to revolutionise the "most un-innovative part of anybody's house", her Loowatt waterless toilet will be shown off to festival goers at Latitude in Suffolk this month
It is the latest move in a project which has raised some £2m in funding along the way including cash from the Bill and Melinda Gates Foundation.
The key to the Loowatt system is a biodegradable lining that runs around the bowl. When the "flush" is triggered, the waste is pushed down into a cartridge beneath which, later emptied into a digester, provides the raw material that is broken down by microorganisms into biogas and fertiliser.
The seed of the idea was sown when Gardiner was given the unglamorous beat of covering the kitchen and bathroom industry shows while working as a journalist on the US design and architecture magazine Dwell.
Irritated by the contrast between the "flush and forget" mentality in her native country – where between four and 13 litres of water are used per flush – and the situation in the rest of the world – two out of every five people in the world have no toilet of any kind – she started working on a new concept during a masters degree at London's Royal College of Art in 2006.
"I realised the best toilet project from my own point of view was to make it waterless, one that turns waste into a commodity and that would work in urban areas," she said.
"Because if you want to do it in a rural area where you are on your own, the technology is already there, but to do it in a city like London seemed to make it more relevant to my life and to the way that globalisation is going – and more challenging: an urban waterless toilet that turns shit into a commodity," she said.
After abandoning an early idea to use worms to do the composting within the home – "way on the fringe of what people are going to want to think about doing" - Gardiner thought of using biodegradable film to move the waste through the toilet, the fundamentals of which survive in the Loowatt today.
"There are these lateral bands that come together and pull the material down in sequence," said Gardiner. The Loowatt technology fits into an area the size of a shoebox and can be fitted to any type of toilet, she said.
When she displayed her first prototype, she installed beside it a toilet moulded out of horse manure, a commentary of how waste could be turned into a commodity.
Seed funding in 2009 then allowed her to focus on sealing technology which prevented odours getting out – a feature from a traditional toilet that she wanted to retain – and work on the anaerobic digestion technology that would convert the waste into fuel and fertiliser.
Digestion systems range in size from small household ones to something the size of a shipping container and even larger. The waste from the Loowatt toilet can be used in any of them, said Gardiner.
Funding from the Gates Foundation allowed the fledgling company to set up its first pilot project in Antananarivo in Madagascar to prove that the system can work. Locals pay to use the toilet, and the waste is converted to energy via an adjoining anaerobic digester. The energy is sold for recharging mobile phone batteries and heating water. Another grant of $1m (£580,000) from the foundation will be used to expand the project to 100 toilets by the end of next year.
The Brixton-based company employs nine people in the UK and another six in Madagascar and Gardiner remains the majority owner of the firm.
Gardiner said the technology could be used in disaster relief situations as well as areas like Antananarivo where toilet facilities are a problem, in addition to the opportunities in western countries such as at concerts and on building sites. No water or energy is needed for the toilet to work, she said, as the small amount of energy required to run the motorised flush can come from a solar panel, taking the whole system "off-grid". The cartridges containing the waste are changed depending on how much they are used.
"The market is massive so there is a huge opportunity there, but it is also very difficult to enter because you are creating a leapfrog technology which is totally new in an area of human life which is very intimate and hard to change," she said.
"By going into both markets, we have reduced risk for the business. If we were only to go after developing countries, it could take a long time to reach revenue and critical mass, the amount that is required to have a future, and in the western context there is a real interest there for having a better solution than chemical portable toilets."
Showcasing the system at Latitude will be Gardiner's first tilt at using it for concerts and large events – which would typically have one toilet per 100 people – and where she aims to have some of her products within two years. Introducing a new technology to risk-averse suppliers of concert facilities could prove difficult however, she said, in a market which is dominated by chemical toilets.
While Gardiner herself has no hang-ups about the bodily functions, the same may not be the case for others. "The potential is enormous. The challenge is getting out there and getting the traction that you need because it is such a different way of doing something because people are very sensitive about the toilet."
• This article was amended on 8 July 2014. The standfirst incorrectly said that the Loowatt toilet uses horse manure. It does not. This has been corrected.
