Taking the sewer less traveled.

It probably doesn't seem like the most savory topic, and it's already my second blog post to reference the porcelain god. But wastewater removal is such a fundamental infrastructural component to sustaining dense developments that it is impossible to ignore or make light of it. For nascent settlements in resource-poor parts of the globe, it could just as easily be the critical prophylaxis against a cholera epidemic. As an instructor of mine once said from a class on housing in developing countries (in her thick Germanic accent): “It all comes down to where de shit flows.” Middle and upper income communities usually have sophisticated enough infrastructure that diverting the sewage away from housing is not a great concern; that process is already fully in place. Instead, wealthier countries can maximize the efficiency at which they convey effluent for treatment and dispersal. For this reason, I should not have been as surprised as I was when I first encountered this toilet at a latrine in central Afghanistan, taken (along with the three subsequent ones) by Beau Sheffer.

Nothing special, of course, though certainly spiffier looking than the rest of the latrine.

For those who have no basis of comparison—which, I suppose, is the majority of the civilian world—this latrine is pretty standard looking, in that it's somewhat tired and battle scarred (presumably only figuratively). My suspicion is that it is at least a decade old, with the predictable accumulation of graffiti over that duration of time. The frame of this modular sink/toilet unit has seen better days, but the toilets themselves are brand new.

The writing is too small to see, but tucked in the back of the seat is the brand name: American Standard. Timeless, renowned for its craftsmanship, and ubiquitous in both private residences and commercial restrooms across the nation. A truly classic toilet. It may have long ago surpassed its resilient top competitors, Kohler, Eljer, and my personal favorite, Bemis. But the operation of this latrine hardly complies with run-of-the-mill American Standard toilets. The clue should be the flush lever. Why is it green?

The symbol to the left of the green lever should provide a clue, but if it doesn’t, a sign on the wall above the toilet and shoulder-height explains more thoroughly.

These are dual-flush toilets, in which a push of the lever in a certain direction controls the amount of water flow used to flush the waste down. It appears the dual-flush apparatus comes courtesy of Sloan Valve, a company specializing in water-saving plumbing technology. As the diagram illustrates, an upward push of the lever releases a standard amount of water of 1.6 gallons per flush for solid waste, while a downward push initiates considerably lower flow, at less than 1.0 gpf, since far less is usually necessary for liquid waste. The intention through this innovation in toilets is to manage the minimum water level necessary to get everything down, thereby saving water for instances when the high consumption levels aren't necessary to elicit a good flush. Over the long-term, water consumption—and the ensuing utility bills—should be noticeably lower.

Dual-flush toilets have become particularly popular in parts of the world that struggle with continued water scarcity. Not surprisingly, Australia first introduced the technology over 30 years ago and has adapted to it more readily than just about anywhere else. Aside from the amount of water employed in a flush, the other large distinction between dual-flush toilets and conventional ones is the siphoning process. When a large volume of water enters the toilet bowl and overflows the exit pipe, it essentially creates a vacuum, which pulls the effluent down during the flush until air enters the process, thereby arresting the siphoning. (A likely more eloquently worded description of the process can be found here.) While standard toilets use this siphoning action, dual-flush toilets employ a larger trapway (the hole at the bottom of the bowl) and a wash-down flushing design that pushes waste down the drain. No siphoning action is involved, and the larger diameter trapway makes it easy for waste to exit the bowl without depending on such a large volume of water. (Discover Company provides a more detailed description.) Conventional toilets until recently have used as much as 5 gallons of water per flush—an incredible waste in any climate, but particularly profligate in a dry one, such as Australia or Afghanistan.

This plumbing innovation has not caught on in the United States until quite recently, so it was quite a surprise for me to find it in an austere military milieu, especially considering that the approach to potable drinking water across ISAF (International Security and Assistance Force) is through individually portioned plastic bottles, which scarcely ever get recycled—and only if the receptacles labeled “recyclables” actually live up to their claim. In short, Operation Enduring Freedom is not seeking ecologically sound solutions to drinking water provision. However, the US military has been far more conservative in its use of all other forms of water—for bathing, cooking, and flushing of toilets, so resource conservation is not entirely foreign. All personnel are encouraged in most instances to take “combat showers”—3 minutes or less—to deal with the finite supply of treated, unpurified water that comes out of the taps in latrines. And it appears that the newer toilets are increasingly adopting dual flush technology to conserve more water. Even if the primary source of drinking water depends heavily on non-biodegradable containers, at least the infrastructure for non-potable water emphasizes a certain moderation.

I have now seen dual-flush toilets more in Afghanistan than I have in the United States, where my only encounter has been in an academic institution—and just one building out of many within this institution. I'm confident there are certain settings in the US where they are widespread, and their prominence is only likely to grow as they assert themselves as a sine qua non within any green building initiative. The US Green Building Council has long included Water Efficiency as one of its fundamental categories for achieving LEED Certified status within New Construction and Major Renovations. The embedded prerequisite of Water Use Reduction mandates that structures will “employ strategies that in aggregate use 20% less water than the baseline calculated for the building”, which, according to the USGBC's standards, is 1.6 gpf for commercial toilets and 1.0 gpf for urinals—exactly on par with the target volumes in dual-flush toilets. Beyond this fundamental requirement, a developer/project manager can earn additional points within the Water Efficiency category through two more credit topics. The first applicable topic is WE-2, Innovative Wastewater Technologies, which recommends that potable water use for building sewage conveyance must be reduced 50% through high-efficiency or even dry fixtures (waterless urinals, composting toilet systems), as a means of earning these additional credits. The second topic is WE-3, Water Use Reduction, which more or less takes the standards from the original Water Efficiency prerequisite and awards additional credits if water consumption can be reduced even further from the baseline, from 30% up to 50%, again through toilets, urinals, faucets, showers, or spray valves. Achieving the 10 Water Efficiency points may be enough to distinguish a LEED Gold-rated building from a LEED Silver. Clearly toilets contribute enough to overall water efficiency to feature heavily in any dialogue on green engineering and construction.

While the USGBC has probably achieved more in elevating the status of dual-flush toilets in the United States, they remain at this point a relative obscurity, limited primarily to commercial construction from the past decade or so. Most Americans have no idea how they work or that such devices exist. While they obviously enjoy a higher profile in Australia or countries with a robust heritage of energy efficient construction (Germany always first comes to mind), some of my recent travels suggest it may have also caught on in the fast-developing world.

This toilet from a higher-end Italian restaurant in the Jumeirah Beach Resort district in Dubai, UAE may appear exactly as one would expect in such a milieu. Typical of toilets in this part of the world, it uses a button to operate the flush, contrary to the lever most commonly employed in the US. And judging from the design of the button, it's a dual flush:

Obviously the smaller button on the right corresponds to the lesser water flow.

A public restroom in Turkey employs a similar strategy for communicating the dual-flush technology. My apologies for the poor photo quality, but it should still be obvious that the smaller button on the right is intended to flush liquid waste.

Turkey is home to what is largely believed to be the oldest flush toilet system in the world, in the ancient Byzantine city of Ephesus, seen below.

Perhaps it should come as no surprise that the Turks boast the latest in resource conserving plumbing infrastructure. Business owners throughout Turkey have in recent years engaged in a campaign to “modernize” restrooms away from the “squat” Turkish toilet, usually perceived as a cathole-in-the-ground and much maligned by Western visitors, despite its comparative simplicity, efficiency, and potentially superior sanitation. The interesting distinction about this toilet is that the structure that houses it is anything but new: it is the Pera Palace Hotel in the Beyoglu district of Istanbul, the definition of luxury for over 110 years, and allegedly where Agatha Christie devised one of her most celebrated mysteries, Murder on the Orient Express. An extensive renovation completed in 2010 most likely resulted in sleek new water-conserving toilets.

One remaining concern, however, distinguishes the American example in Afghanistan from the other countries and which the water conservation efficacy of these two dual flush toilets hinges upon: without an instructional sign, would the average user know how it works? I am not in a position to determine whether such toilets are commonplace in either of these two countries. I didn’t see too many other examples during these recent travels, though if I were to guess, I suspect dual-flush technology is far more common in the United Arab Emirates than in Turkey. Even if they are a sufficiently common occurrence that Turks and Emiratis know which button to push, it’s hard to imagine that too many foreign visitors would know how to react when confronted with both a small and large button, either in Dubai—where, on average, 80-90% of the population consists of expatriates, or this particular hotel in Istanbul, which targets moneyed foreign tourists, often from elsewhere in Europe or North America. And if these visitors use the buttons incorrectly out of ignorance, it would easily nullify any of the potential for resource conservation.

Thus, the real effectiveness of this campaign may boil down to semiotics. Just about any populist environmental initiative requires an outreach campaign to get people on board—the lack of basic communication would guarantee that even those with a genuine interest in conservation will remain in the dark. Dual-flush technology may currently be a pioneering effort in the US, the brains behind the toilet latrines in Afghanistan seem far better at gauging their potential user than the more elegant but less informative versions in UAE and Turkey. For the record, the one dual-flush toilet example I saw in the US also had an explanatory label.

Chances are strong that this blog post, which regards these dual-flushers as an obscure novelty, will seem quaint within five to ten years. Before long, water-efficient toilets will undoubtedly become widespread enough that Americans no longer depend on the signage to tell them how it works, which is already apparently the current condition in much of Australia (and most likely other countries as well). One day, the two buttons above the toilet—or the green up-down lever—will seem as natural and self-explanatory as the blue recycle bins with the Mobius Loop. However, we can never optimize resource conservation—it is a perpetual teleological process, raising the bar steadily over time. One can only anticipate that American Standard, or Bemis, or Sloan will devise a new machine in a few years to resolve the latest perceived inefficiency, and eventually that new device will supplant the dual-flush toilet, which will at that time seem archaic. Hopefully these innovators will be as savvy toward outreach and self-promotion as they are at engineering.