Reinvent the toilet, save the world? Ecuador is betting on it.

In developing countries, environmentally friendly and practicality don't always go hand-in-hand. Biogas are changing that. With biogas technology, methane is derived from the feces of humans and animals and is used in place of traditional fuel which improves sanitation across these regions and is a benefit for the environment.

Thanks to a modernized waste-management system introduced by Tanzania in 2014, Kenya is able to see a future for fixing their quickly growing trash pollution problem.

Across the world, 1.8 billion people have to make a daily decision between either drinking unsafe water or paying exorbitant prices for bottled water. I-Drop Water, a company that has devised purification systems that can be installed at affordable rates in local grocery stores, is working to solve this problem by bringing accessible purified water to people throughout Africa.

Haiti is currently battling the biggest cholera epidemic in recent history caused by lack of access to clean drinking water. Soil is an NGO which delivers dry, compost toilets to peoples’ homes - alternatives to water guzzling flushing toilets, which need infrastructure such as sewers - to help keep sewage from contaminating water sources and provide dignified, safe toilet facilities.

A public health campaign effectively reduced the incidence of malaria by sensitizing the community to the health risks of dumping waste indiscriminately, providing medical outreach and treatment for malaria, and cleaned up existing waste, which was moved to designated dumpsites.

Companies and research initiatives around the world are developing and testing new toilets that can collect human urine and turn it into fertilizer. These urine diversion toilets have been implemented in places like South Africa with mixed results. However, researchers in Sweden are using portable toilets to gather the urine, dry it into fertilizer pellets that are then used to grow barley for beer. This work could show how to implement these kinds of toilets on a large scale.

BlueConduit, an analytics startup, applies statistical models to identify neighborhoods and households that might have lead pipes. The models include dozens of factors, such as the age of the home and proximity of other homes where lead has been found, to help predict likely locations of lead pipes and create a ranking by likelihood that cities can use to prioritize which pipes to examine. In Flint, MI, about 70% of the homes identified using the models had lead pipes, compared to about 15% of homes where excavations did not use the model. The company is working with organizations in dozens of other cities.

After realizing that chemical fertilizer was doing more harm to the land than good in Burkina Faso, a Burkinese agronomist created a fertilizer from organic waste that has allowed the land to once again become fertile. Although the organic fertilizer promises a much higher increase in yields, chemical fertilizer is still widely used in the region.

Stanford University graduate Gayatri Datar founded a nonprofit called EarthEnable that aims to rid the world of dirt floors. EarthEnable sells an earthen floor covered with an environmentally friendly varnish at a cost less than a concrete floor. To date the organization has installed more than 4,400 floors, and customers and the Rwandan government love them.

Bhutan has committed to eliminating malaria from the country, as in on track to do so thanks in part to the Bhutanese government's consistent persistence to raise public awareness. Arming citizens with mosquito nets, spray and education, the small country has now outpaced India towards this public health goal.