Free
By 2030, the world population may be more than 8.5 billion people. That’s up almost a billion from where it is now.
All those people will need food, but where will it come from? They will also generate a lot of waste, and that has to go somewhere. A lot of farmland and many rivers and lakes will need to be protected from pollution. Many solutions to these problems come from environmental engineering.
◀ Norma Alcantar is a chemical engineer who used her knowledge on an environmental problem — polluted water. She was inspired by something she learned as a child from her grandmother in rural Mexico. People there cut and boiled a prickly pear cactus and used the boiled water to purify their drinking water. In her laboratory, Alcantar learned that the key ingredient was inside the plant’s leaves. She made biobeads, or pellets, from that part of the plant. Then she tested her idea on water in Haiti that became polluted after an earthquake. It worked.
A swale is a low place between two ridges. A bioswale is a low place filled with grass, trees, or other plants. The plants in a bioswale make rainwater sink into the soil slowly. Water moves among the roots, which remove most of the pollutants. Engineers and landscapers use these types of plantings. They help filter the water that flows into rivers, streams, or sewer systems. ▶
◀ When you flush a toilet, the water moves everything down and out toward the sewer. That may mean up to six gallons of water down the drain. (Newer toilets use less water.) What if you live in or near a desert, where there’s less water? Or in an area with no sewage lines? Environmental engineers have solved that problem with bio-toilets. Some of these toilets use materials like sand or sawdust to turn waste into compost. The process takes about 25 days. It results in dry material that has no odor and only about 5 to 10 percent of its original mass.
▲ Winds at high altitudes provide more than four times the energy of winds near the ground. Knowing this, engineers ask, how can we use high-altitude winds to generate power? Their answer is wind turbines mounted on kites. Of course, these are not regular kites. They’re about 100 feet long and made of thin strands of carbon. Flying up to 2,000 feet above the ground, a kite’s turbines can generate 600 kilowatts of energy. That’s enough to power around 300 homes. And it’s about twice the power a wind turbine on the ground makes.
◀ More than 800 million people in the world don’t get enough food. One reason is that not enough food is being produced. Engineers have designed indoor farms as a solution. This particular farm is about half the size of a football field. With thousands of LED lights and controlled conditions, the lettuce here grows twice as fast as it does on a traditional farm. About 10,000 heads are harvested each day.
