Tag Archives: sanitation


Kitchen sponges are hotspots for bacteria. Sanitizing methods like microwaving don’t seem to work


Microbes love wet environments. They also enjoy food — any kind of nutrients will do since they’re not picky at all. This makes kitchen sponges, which stay wet for most of the time and are packed with leftover scraps, excellent breeding grounds for bacteria. This can turn into a serious health hazard seeing how sponges are supposed to clean the dishes and cutlery that we use to eat. Some studies have suggested that households can reduce the risk of hazardous bacterial infections by sanitizing kitchen sponges.

Some studies have suggested that households can reduce the risk of hazardous bacterial infections by sanitizing kitchen sponges. A new study suggests that these methods aren’t really effective — not even microwaving. Instead, households should turn to cheap sponges that they should replace weekly.

Few places, if any, in our home have more bacterial density then the kitchen sponge

German researchers at the Furtwangen University studied 14 used kitchen sponges separated into top and bottom parts. In total, across all household sponges, the scientists found these yielded 362 operational taxonomic units (OTUs), which are pragmatic proxies for bacterial ‘species’.

After sequencing the cultured bacteria, the researchers ended up with 220,000 raw DNA sequences representing  9 phyla, 17 classes, 35 orders, 73 families, and 118 genera of microbes, as reported by Ars Technica. The most prominent bacteria belonged to the Moraxellaceae family. These are typically found on the human skin and previous studies identified them on virtually every kitchen surface that people typically clean using sponges, from fridges to stoves. These are also the same ‘stinky’ bacteria that make dirty laundry smell bad.

Other notable bacterial species were those belonging to the Proteobacteria, Bacteroidetes, and Actinobacteria phyla. Some of these have been previously identified with moderate diseases.

(A) Kitchen sponges, due to their porous nature (evident under the binocular (B) and water- soaking capacity, represent ideal incubators for microorganisms. Scale bar (B): 1 mm. Credit: Scientifi Reports.

(A) Kitchen sponges, due to their porous nature (evident under the binocular (B) and water- soaking capacity, represent ideal incubators for microorganisms. Scale bar (B): 1 mm. Credit: Scientifi Reports.

In terms of raw numbers, kitchen sponges are teeming with bacteria. The team led by Markus Egert found bacterial densities as high as  5.4 x 1010 or 54 billion-bacterial cells per cubic centimeter of uncleaned kitchen sponge.

“Kitchen sponges are likely to collect, incubate and spread bacteria from and back onto kitchen surfaces, from where they might eventually find their way into the human body, e.g. via the human hands or contaminated food. In addition, direct contact of a sponge with food and/or the human hands might transfer bacteria in and onto the human body, where they might cause infections, depending on their pathogenic potential and the environmental conditions,” the authors wrote in a paper published in Scientific Reports.

Previously, researchers found sanitation through boiling or microwave treatment can significantly reduce the bacterial load of kitchen sponges. Naturally, people regarded the news as a reasonable hygiene measure, which we also covered in detail in the past. Egert argues, however, that these lab studies do not accurately reflect real use. The few sponges that he and colleagues collected from sponge owners who microwaved or hot-soaped them “did not contain fewer bacteria than uncleaned ones.”

Moreover, the bacterial species from the ‘sanitized’ sponges contained more bacteria related to diseases. That may be due to the fact the surviving bacteria are stronger and once they recolonized the sponge, the whole population was more resistant.

“This effect resembles the effect of an antibiotic therapy on the gut microbiota and might promote the establishment of higher shares of RG2-related species in the kitchen sponges. Although further analyses, including controlled sanitation experiments, are needed to substantiate these findings, our data allow careful speculation that a prolonged application of sanitation measures of kitchen sponges is not advisable,” the authors noted.

The paper highlights the fact that used kitchen sponges contain more bacteria than previously thought. It also shows that the “long term perspective, sponge sanitation methods appear not sufficient to effectively reduce the bacterial load in kitchen sponges.” What Egert and colleagues advise instead is to regularly replace kitchen sponges, preferably weekly.

The solar char toilet developed at University of Boulder Colorado.

Solar powered toilet locks greenhouse gases and increases crop yields

One of the 16 teams involved in a collaborative project funded by the Bill & Melinda Gates Foundation that aims to help some of the 2.5 billion people around the world lacking safe and sustainable sanitation recently unveiled their innovative design: a solar-powered toilet that treats solid waste by effectively carbonizing it. The concentrated solar power delivers high energy in the waste chamber, sterilizing it and transforming it into biochar – a highly porous charcoal used to both increase crop yields and sequester carbon dioxide.

Karl Linden, professor of environmental engineering at University of Colorado Boulder, and colleagues developed a next-generation toilet destined for poor and unaccessible areas where waste disposal isn’t effectively disposed of in a centralized manner.

The solar char  toilet developed at University of Boulder Colorado.

The solar char toilet developed at University of Boulder Colorado.

The high tech latrine consists of eight parabolic mirrors that focus concentrated sunlight to a spot no larger than a postage stamp on a quartz-glass rod connected to eight bundles of fiber-optic cables, each consisting of thousands of intertwined, fused fibers, said Linden. The energy generated by the sun and transferred to the fiber-optic cable system — similar in some ways to a data transmission line — can heat up the reaction chamber to over 600 degrees Fahrenheit to treat the waste material, disinfect pathogens in both feces and urine, and produce char.
Char is a very useful material because of its high water retaining properties. A soil mixture containing 10 percent biochar can hold up to 50 percent more water and increase the availability of plant nutrients, thus helping improve crop yields. Additionally the charcol has carbon mitigating properties, helping reduce greenhouse gases released into the atmosphere. Alternatively, you can release the trapped carbon back into the atmosphere by burning it to extract energy comparable to that of commercial charcoal.

“We are doing something that has never been done before,” said Linden. “While the idea of concentrating solar energy is not new, transmitting it flexibly to a customizable location via fiber-optic cables is the really unique aspect of this project.”

Tests have shown that each of the eight fiber-optic cables can produce between 80 and 90 watts of energy, meaning the whole system can deliver up to 700 watts of energy into the reaction chamber, said Linden. In its current form, the toilet was designed to meet the needs of six people a day, however larger facility that could serve several households simultaneously are currently being considered. The key here is cost, especially considering the toilet’s target group. The researchers claim a cost level of five cents a day per user can be reached.

The team of researchers involved in the project will travel to Delhi, where their invention along with 15 other produced by researchers from other University will be on display March 22. Other institutional winners of the Gates Foundation’s “Reinvent the Toilet Challenge” range from Caltech to Delft University of Technology in the Netherlands and the National University of Singapore.

“We have a lot of excitement and energy on our team, and the Gates Foundation values that,” Linden said.  “It is one thing to do research, another to screw on nuts and bolts and make something that can make a difference. To me, that’s the fun part, and the project is a nice fit for CU-Boulder because we have a high interest in developing countries and expertise in all of the renewable energy technologies as well as sanitation.”

The PeePoo bag: don’t poop where you eat

Nairobi, Kenya is home to one of the world’s biggest slums, more than one million people living in subhuman conditions in the African state capital. I’ve seen and read a lot of reports from there, and other African states alike, and the situation is indeed dire. Imagine having nothing to eat – now imagine having to poop the scraps of food you manage to go about during the day in the same one room apartment you have to live in.

Although public latrines are common in slums, they’re overused, insalubrious and even dangerous (women and young girls often get raped near latrines at night), so people resort to what’s commonly know as “flying toilets”, which basically means filling a plastic bags with one needs and then throwing it down right the window.

Basic sanitation, like for instance running water, is a far fetched concept for any slum dweller, due to over population and lack of infrastructure. Crap, forget about running water, think about clean water which ever so dim, gets even more contaminated with unfiltered, unsanitized waste. Every 15 seconds a child dies in the world from contaminated water and dysentery or cholera pass for common flues.

Some of you may ask how can something like this be possible in a world that calls itself civilized, where reason and technology are supposed to thrive, however traditional sanitation infrastructure is expensive and hard to implement. Of course, if government officials would start thinking about their people and stop spending western funding on buying a Rolls Royce so they can drive it across the whole 5 miles worth of paved road or on pale, white prostitutes things might have looked different, alas this is a discussion that is both interminable and unpleasant for me to enter here.

Back to Kenya and their sanitation issue, it seems a group of individuals, extrapolated on the crap filled plastic bags hovering over Nairobi and developed, let’s say, a more elegant solution.

Introducing the Peepoo…

The Peepoo bag is a long thin bag (14 x 38 cm) with a guaze liner, and coated on the inside by a thin film of Urea, which is the most common fertiliser in the world and is a non-hazardous chemical. When this chemical comes into contact with human waste, be it  faeces or urine, an enzymatic breakdown takes place into ammonia and carbonate, driven by enzymes which are naturally occurring in faeces. As the process develops, the pH levels found in waste increase, and as a result hygienization  occurs.  Waste born pathogens (viruses, bacteria and parasites) are killed over a period of a couple hours to a few weeks. Also, the bags are fully biodegradable and are actually helpful for the environment, acting like a fertilizer.

The benefits of this product are evident – waste is no longer moved around, but safely assimilated by the environment and, of course, there’s no water use. I’m a bit confused, however, how this project is actually implemented. Like I said, there are over a million people living in sub-human condition in Nairobi alone. This means, millions of such Peepoo bags are required every month. Who will pay for these, are they free for the every day African? Because it’s pretty clear to anyone from the start that someone who lives on less than a dollar a day won’t pay in his right mind anything for a bag to take a crap in.

The PeePoole behind the project deserve have our recognition, because however difficult to implement the idea sounds, it’s still a step ahead, although I believe Kenya’s, and the whole third world actually, problem lies in the social upbringing and levers. It’s  enough to read some reports written by various peace corps volunteers detailing the African mindset, will or work power, respect for ones country, those around him and even self, education and so on. It’s pretty clear Governments are interested in solving anything, and it’s up to the people over there to help themselves, to an extent.

I’d love to see this project well funded and spread towards other third world countries as well. I’d also love to hear some of your thoughts and remarks on the subject as well, so please don’t be afraid to voice out and leave a comment below the post .

Find out more at www.peepoople.com