Sanitation Attitudes and Technologies for Sustainability
Making Sanitation more SustainableA growing global movement aims to make sanitation more sustainable by changing how both rich and poor countries think about human waste - recasting it as a valuable resource that is most costly when thrown away.
Ecological Sanitation - EcosanA philosophy known as ecological sanitation, or "ecosan," is fueled by a convergence of factors - the rising prices of energy and artificial fertilizer, increasing worries about food security, and concern for the environment.
In Europe, recent years have seen the advent of "urine diversion" toilets, which separate the two kinds of waste in order to treat it more efficiently, among other benefits.
And several European pilot projects have begun to experiment with vacuum-biogas toilets, which require very little water and turn waste into energy.
Skeptics point to the cost, health concerns, and challenge of changing deeply ingrained habits and beliefs. Depending on the particular kind of system, the changes could entail a different experience of the toilet, or a different attitude toward the waste, or both.
For some proponents of sanitation reform in developed countries, that's part of the point: changing everyday behavior is going to be key to solving our ecological crises.
Flush and Forget -- Ignores the Repercussions of Waste DisposalAccording to Arno Rosemarin, research and communications manager at the Stockholm Environment Institute, our current "flush and forget" system makes it too easy to ignore the repercussions of waste disposal. If we are going to make meaningful changes in our environmental impact, the reasoning goes, perhaps we should start by thinking differently about the emissions that we ourselves produce.
China and Japan have long traditions of re-using human waste as fertilizer. Even in England, as recently as the 19th century, "nightmen" would take human waste from backyards to sell to farmers.
But that was before the British "sanitation revolution." Exactly 150 years ago this summer, the river Thames in London overflowed with human waste in what was known as the Great Stink, forcing Parliament, located on the banks of the Thames, to take action. Sewers were subsequently installed, eventually resulting in major public health advances.
The flush toilet and its infrastructure have since become standard throughout the developed world.
The system's benefits are obvious, but it also has downsides that are growing increasingly apparent.
Greywater or BlackwaterThis large quantity of contaminated liquid further mixes with "greywater," the water from the laundry, shower, and sink, tripling or quadrupling the amount of water that must be treated as sewage in energy-intensive plants. In effect, the system takes a relatively small amount of pathogenic material - primarily the feces - and taints enormous amounts of water with it. Especially in regions struggling with freshwater scarcity, many observers have come to see this system as highly inefficient.
In this model, it's not only water that's wasted, critics say - it's also the valuable nutrients in the feces and urine, notably phosphorous. Global fertilizer prices have tripled in the last year, partly due to a shortage of phosphorus, which some see as a looming crisis.
Rose George, author of a forthcoming book about sanitation, "The Big Necessity," says of the conventional system, "It was a solution 150 years ago and it was a very good one, but it should evolve."
Current Technology ChangesIt has become common for treatment plants to convert some of the methane generated by sludge into biogas to partially power their own plants. Low-flush toilets and waterless urinals are small steps to conserve water. And the practice of using treated sludge - renamed "biosolids" - as chemical fertilizer has become customary in parts of the developed world. In the United States, according to the Environmental Protection Agency, about 50 percent of all biosolids are being recycled to land.
Sludge FertilizersThe Massachusetts Water Resources Authority turns all of its sludge into fertilizer, some of which it sells commercially through a contractor and some of which it gives to communities.
But ecosan advocates assail this practice as unsustainable and unsafe. Under the current system, household waste mixes with industrial waste, including toxic materials. Although the EPA has issued treatment regulations, and the MWRA defends the safety of its fertilizer, there are concerns about the impact of sludge-derived products on soil and human health.
Home-Based Separating...like Recycling BinsThe most radical visionaries of this movement would apply the same principles to sanitation that we have begun to apply to other garbage in our homes. Just as we separate plastic, cardboard, and newspaper, says Rosemarin, we should separate urine, feces, and greywater.
"Don't Mix What God SeparatesAs a first step down this road, some companies are producing new types of toilets. One idea, pioneered in Sweden, is known as urine diversion. The basic concept is that the toilet has two receptacles for the different kinds of waste. "Don't mix what God separates," says Steven Sugden, a research fellow at the London School of Hygiene and Tropical Medicine who has worked on sanitation projects in Africa.
Urine as FertilizerThe benefits of taking urine out of the waste stream are clear: Urine makes up less than 1 percent of all waste water in developed countries, but contains a huge proportion of the nitrogen and phosphorus. Those nutrients are essential to agriculture but harmful in water bodies, and removing them is the most energy-intensive part of treating waste water. And since urine is almost sterile, it can be used as fertilizer with little to no treatment.
Biogas Vacuum ToiletsVacuum toilets, much like those on airplanes, are also gaining currency. These typically require less than a quart of water per flush. A promising innovation is the vacuum-biogas toilet, in which waste is sucked into a vacuum sewer system, and then transferred to a local biogas plant.
Compost ToiletPerhaps the simplest mechanism is a compost toilet that looks normal from the outside, but inside, the waste drops into a dark hole. A ventilation system pulls air down to prevent odor. In the space below, the liquid and solid waste separate. The liquid can be used immediately as fertilizer, while the solid waste is stored for at least one year - with monthly raking and the addition of pine shavings - and then is ready to be harvested as compost. Compost toilets sell mainly to parks, green buildings, and nature centers.
Obstacles to widespread implementation of unorthodox toilets.Space limitations make compost toilets infeasible in most urban areas.
Vacuum toilets require a different plumbing system.
And there may be psychological barriers to changing habits in the bathroom.
Changing the Structure of SanitationPartly due to the lack of infrastructure, it's in the developing world where the biggest changes have so far taken place. The problems there are quite different. Due to the lack of proper sanitation facilities, diseases caused by ingested fecal matter are rampant; diarrhea, for example, kills more children than AIDS. But the advantages of the ecosan approach are similar, because a well-designed system allows people to harvest the benefits of waste.
Learning from Others
Read the full, fascinating story at the SOURCE: Boston Globe
The Big Necessity -- Water and Waste Reuse and Effective Reclamation
Los Angeles develops Solid Waste Integrated Resources Plan
Related Green ResourcesMarcom Tips
Interactive & Video Tips
We encourage lifelong learning to support sustainable communities and provide these select resources to help you pursue green and sustainable self-development:Lorman Business Training Directory of On-line Business and Compliance Classes
Green Job Wizard Job and Career Certifications Directory
Job & Career Resources
Contact Us ~ Home
Text Link AdsAD: Place your link here
|CONSUMERS | Backyard Nature | Senior Health | MultiMedia Marketing | Marketing | Networking Events | Japan ||