WWF said that if just one-tenth of Swiss restaurants adopted the system, the country could shut down a nuclear power plant.
The green group said it was looking for 100 schools, university cafeterias and restaurants ready to install the special plumbing as part of a pilot project.
The organization said developing a similar toilet for women was a more complex process, but that researchers hoped to have one ready by 2016.
You are right to be suspicious.
The WWF was just one of dozens of organizations, media outlets, Internet companies and others who played April Fool’s Day pranks.
April 1st is a day when readers in Switzerland have to be careful about the news they read on websites to avoid being taken in as “poissons d’avril” by items that sound plausible, even if far-fetched.
The NZZ online announced that Valais was mounting a a bid for the 2026 Winter Olympics.
Le Matin reported that colourful Lausanne Mayor Daniel Brélaz had banned the use of a photo showing his wife posing semi-nude for a travelling exposition on family violence.
Geneva newspaper Le Courrier reported that 30 MPS from the canton danced the Harlem Shake to raise funds to defend the diversity of the press.
Elsewhere in the world, similar gags abounded.
Internet giants went all-out to try and bamboozle their users with April Fool's jokes on the most mischievous day of the year.
YouTube is shutting down, Twitter users have to pay for the use of vowels, and the new Google Nose search engine will bring a whiff of wet dog or daisies right to your computer or smartphone.
These were just some of the fake stories published to reel in the fish.
YouTube, the world's largest video sharing site, revealed it had merely been an eight-year contest to find the best video and would be closing to review all the entries. The winner would be announced in 2023.
"We are so close to the end," said Tim Liston, named as "competition director".
"Tonight at midnight, YouTube.com will no longer be accepting entries," Liston said
"After eight amazing years, it is finally time to review everything that has been uploaded to our site and begin the process of selecting a winner,"
In keeping with its prankster reputation, Google also unveiled a complex search engine that would offer "the sharpest olfactory experience available".
The search engine claims to have a database of smells from all over the world.
Users can search for "new car smell", or "Egyptian tomb", sniff their screen and even share it with a friend.
Meanwhile, micro-blogging site Twitter said it had decided to shave off even more characters by providing a new vowel-free service to users.
Several recent newsmakers were targeted in April Fool's Day pranks, with North Korea cropping up twice.
South Africa's Daily Maverick newspaper carried a story headlined "Exclusive: Oscar Pistorius signs up for North Korea's inaugural Friendship Run."
The paper said the double-amputee paralympian sprint star, who is charged with killing his model girlfriend, will lead South Africa’s team in Kim Jong-Un's bid to build bridges between less understood world regimes and less understood global figures.
In Belgium, the French-language state-owned radio station reported that former French president Nicolas Sarkozy and his wife Carla Bruny, were moving to Brussels.
The Huffington Post news website, meanwhile, reported that the wealthy Qatari backers of London's Shard skyscraper were building the "Shlide", a heart-stopping thrill ride curving all the way down the 72-floor building.
Providing an image of the slide, the site quotes project coordinator "Dizzy" Lizzy McGovern, who said there had been some teething problems in the project.
"We wish Brian, the initial tester, a speedy recovery after the operation to replace both his knees."