How do we solve water scarcity? Or prevent floods? Or treat polluted water? This year’s finalists in the Stockholm Junior Water Prize address these basic water challenges in sophisticated, innovative ways. Read about a few of the exciting projects.

Thousands of young people around the world have conducted water-related projects for the 22ndannual Stockholm Junior Water Prize. Here are five projects from some of the 32 countries competing. The winner will be announced on August 28.

1. Using moth larvae to break down “flushable” wipes

Cleaning wipes used for personal hygiene and baby care are clogging sewage systems in major cities across the world. The objective with this project is to ascertain whether the larvae of Galleria mellonella, known as the greater wax moth, can metabolize the non-biodegradable compounds found in cleaning wipes. This could pave the way for a natural mechanism for eliminating this kind of waste.

Project: Breaking down cleansing wipes using Galleria mellonella: an ecological solution to the problem in treatment plants
Finalists: Miguel Aragón Fernández and Miguel Sequeiros Doval, Spain.

2. Creating carbon nanotubes from plastic grocery bags

This project involved converting LDPE plastic bag waste into multiwalled carbon nanotubes (MWCNT) used for wastewater treatment. Conventional methods for synthesizing these nanotubes involve complex reaction system design, toxic chemicals and the production of hazardous wastes. The new process uses a novel Fe-Al catalyst in a closed system, creating a sustainable solution for removing hexavalent chromium and industrial synthetic dyes.

Project: Combating water contamination using plastic waste
Finalist: Didarul Islam, Bangladesh.

3. Collecting household water from the air

In this project, a thermoelectric cooler was used to condense air moisture into droplets of water. The prototype was designed using cheap and easily accessible materials, such as a CPU, a sealed lead acid battery, an aluminum heat sink, solar or wind power, and a thermal compound. Over a 24-hour period, 1.2 liters of water is collected, which can be used for household purposes.

Project: Water from air: The Rainmaker
Finalist: Kwazi Zwezwe, South Africa.

4. Using plant waste as wastewater filters, then as crop fertilizer

Agricultural plant-wastes such as corncob were recycled into a multi-purpose biochar, which could act as wastewater filters before being reused as crop fertilizer. A novel, self-sustaining biochar model was engineered, which maximized its adsorption of harmful wastewater nutrients to 45.6%. This level is competitive with current bioadsorbents, and significant as this was achieved within in-situ conditions involving competitive adsorption.

Project: Recycling waste into biochar: A novel, sustainable model of wastewater filtration and crop fertilization for the agricultural industry
Finalist: Minh Nga Nguyen, Australia.

5. Removing heavy metals from water using bacteria

The goal of the project was to create a cost-effective, low impact system to remove heavy metals from water systems. 250 bacterial strains were isolated from water samples taken at EPA Superfund Sites. The 24 bacteria that showed the greatest potential for heavy metal remediation were then selected and identified. To create the system, the bacteria were combined with mixed algae in an immobilized format called a sodium alginate bead.

Project: The development of a novel heavy metal bioremediation system
Finalist: Braden Milford, USA.

See all of the finalist projects in the Stockholm Junior Water Prize