In physics and chemistry, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium.

A beetle that lives in the Namibian Desert, one of the hottest places on Earth, survives by using its bumpy shell to draw drinking water from periodic fog-laden winds. As morning fog sweeps across the desert floor, the water sticks to the peaks of Stenocara’s bumps, eventually forming droplets. When the droplets become large and heavy enough, they roll down from the top of the peaks and are channeled to a spot on the beetle’s back that leads straight to its mouth.

The beetle’s prodigious water harvesting abilities captures ten times more water than existing fog catching nets. The beetle’s ability to pull water from fog is due to bumps on its wing scales that have water-loving tips and water-shedding sides.

A novel type of nanomaterial has been developed which has a pattern of alternating substances of differing properties. Raised sections are hydrophillic (water attracting), which cause tiny (15-20 microns) water droplets to attach. As these droplets increase in size as more water is added, they spill over to the nearby lower hydrophobic (water repelling) surfaces, which causes the droplets to bead up and roll downwards via gravity to a collection system. These water-harvesting sheets are useful for capturing water in cooling towers and industrial condensers, arid agricultural systems, and buildings in fog-rich areas.

The inspiration? A lotus blossom. Water drops bead up and roll off of the leaves’ water-repellent surface, washing away every speck of dust. The secret behind the ability of the lotus is in the tiny surface features, consisting of tiny nubs, on the leaves. These tiny protrusions don’t provide a surface for water drops to form, so the surface doesn’t get wet. Instead, the drops form into beads and roll off the surface carrying away any particles in their path. On a normal surface, water drops form hemispherical shapes and instead of rolling, glide over the surface. This spreads and smears dirt particles but does not remove them.

A special substance is synthesised from a group of compounds known as diarythenes to form a microcrystalline film, which has a smooth surface. When this film is irradiated with UV light, the surface ceases to be smooth.

Instead it is covered with a fine down of tiny fibers that have a diameter ofabout 1 µm. This down has a similar effect to the micronodules on the lotus blossom, resulting in a super-water-repellent surface. If the surface is irradiated again, this time with visible light, the fibres and color vanish, leaving a colorless, smooth, and wettable surface.

This type of self-cleaning surface would be very useful to us as well: No more car washes, no more dirty windows, no more signs obscured by mud or dust, all as an inherent ability of the object.

A water filter that works like a whale’s baleen. Called Baleen Filters, it requires no pressurization (which is what normally causes filtration to use energy) and clean themselves (which avoids creating waste and needing maintenance). "Gunky" Water (with sludge, oil etc.) is poured over a screen that is much bigger than the water stream; as the screen catches gunk (which blocks water flow), the water naturally flows over the gunked-up part of the screen to the nearest part of the screen that’s still clean, so it still gets filtered; then every so often a power-sprayer comes along at an oblique angle, pushing the gunk collected on the screen away into a separate tank where it can build up without blocking the filter. The Baleen Filter can filter particles down to 25 microns without needing chemical treatment.

The problem is not a fundamental lack of water. Even in places where water is not scarce, it is often contaminated or "impaired" with natural containments and fertilizer runoff containing nitrates and perchlorate. While systems exist for dealing with these problems, they typically concentrate compounds and are costly to maintain.

This may all soon change. Bacteria might do the dirty work — converting wastewater to clean drinking water using a minimal amount of energy and generating no harmful waste. There are organisms that happily take oxidized contaminants and, with the addition of hydrogen gas, reduce them into harmless substances. But delivering hydrogen to the microorganisms in a safe and effective manner has always been the sticking point until now.

Now scientists have devised a way of using a membrane biofilm reactor to transfer hydrogen directly to bacteria that convert nitrate into nitrogen gas, perchlorate into chloride ions, and other toxins into harmless forms.

As the device operates at room temperature, produces no toxic waste, and uses little energy, it costs considerably less than existing containment-removal technologies. It has a lot of potential for use in municipal water plants and could even someday, be used at the village level that would otherwise lack the resources to remove these potentially harmful compounds.

The Biolytix Filter is a compact septic system that mimics the structure and function of decomposer organisms along a river’s edge. In the Biolytix system, worms, beetles, and microscopic organisms convert solid sewage and food waste into structured humus, which then acts as the filter that polishes the remaining water to irrigation grade. The treated water is then distributed through shallow tubes to irrigate lawn and landscape. The system uses 1/10 the energy of conventional sewage treatment systems, needs no chemicals, and produces irrigation water that is safe for the environment.