A major US city will start drinking its own sewage. Others need to follow.

Israel has grappled with crippling drought for years. But people have learned to use Mediterranean sea water and recycled wastewater to provide the country with enough water for all its needs.

Washing hands in between contact with patients is one of the most important things a healthcare worker can do to prevent the spread of disease and reduce the rise of superbugs like MRSA. A new technology is increasing rates of hand washing by displaying, via a sensor in an employee's badge, whether the healthcare provider has washed their hands recently.

After the drought hit Australia in the early 2000s, city officials had to start thinking seriously about ways to conserve and creatively store their water. External tanks became the solution, storing rain runoff to create an available source of water for Melbourne residents. This solution may not fit every location, but there are other teachable lessons such as taking radically shorter showers.

Laws in Texas and New Mexico, both locked in the grip of a crippling drought, don't do much to actually encourage citizens to conserve water. New conservation laws and financial incentives are trying to change that.

Ecological toilets that use natural composting to break down waste are simple to construct, waterless and are easy to fix. But as philanthropists are finding, getting these to those that need it most is harder than anticipated.

The company that manufactures Lifestraw, a water purification device, has found a way to distribute their product to impoverished Kenyan families for free, while still making a profit. In the global carbon credit market, businesses receive carbon credits for projects that reduce greenhouse gas emissions. These credits can then be sold to companies who need to offset their carbon emissions, allowing green companies to make a profit off of their small ecological footprint.

Although patients go to hospitals to receive medical care, many Americans will acquire infections that did not already have them. The United States as a whole has made modest progress at reducing the rates of hospital-acquired infections. Spearheading the efforts, the Veterans Affairs Medical Centers have devised anti-MRSA strategies to keep patients safe.

New York City black tar roofs cause a number of environmental problems, including air pollution, heat absorption that raises energy consumption, and storm water runoff in the sewer system. Efforts to turn these old roofs into green spaces cool the buildings, enable the containment of more rainfall, reduce sewer discharge, generate energy, and absorb carbon emissions. New York City has a pilot program offering financial help for green roofs.

The company that manufactures Lifestraw, a water purification device, has found a way to distribute their product to impoverished Kenyan families for free, while still making a profit. In the global carbon credit market, businesses receive carbon credits for projects that reduce greenhouse gas emissions. These credits can then be sold to companies who need to offset their carbon emissions, allowing green companies to make a profit off of their small ecological footprint.

Clean water and healthy ecosystems are becoming increasingly difficult to come by. With floating islands and other inventions, eco-entrepreneur Bruce Kania thinks that biomimicry - such as reconstructing wetlands and growing biofilms - can tackle the toughest of water problems.