Clean Water of Our Future: Bacterial Farming for water purification
“Water pollution” is the contamination of bodies of water and is a big public health problem around the world.
Water pollution is the leading worldwide cause of death and disease, causing more deaths than wars and any other illness on the planet. Since water is a great solvent, finding ways to filter waste from the water can become a very expensive and technically hard problem.
The causes of water pollution are often a result of human activities and can include a wide range of chemicals and pathogens as well as organic substances like bacteria. This also includes inorganic substances like heavy metals such as arsenic, cadmium, lead, mercury, and nickel.
Water is vital for humans and many other living creatures here on Earth. It regulates body temperature, flushes body waste, and makes nutrients accessible, so it is impossible to live without. But unsafe water is consumed every day by many people. This leads to the transmission of diseases like cholera, diarrhea, dysentery, and polio. The consumption of heavy metals can also deliver long-term damages to kidneys, livers, bones, and the brain.
Water pollution impacts people's lives around the world constantly. Preventable diseases are killing people at a staggering rate. Can we create a safe, long-term solution for this great humanitarian problem?
What if?
What if we could create a long-term, inexpensive, and self-sufficient solution to improve water that is contaminated with bacteria and heavy metals?
Meet the team
Luel, Alyssa, Erin, Stephen, and Jamar are 15 and 16-year-old students from Robeson High School in Philadelphia.
Together with Firsthand, a STEAM Initiatives Program from the Science Center in Philadelphia, and Aula Future, they decided to take part in the 2021 Biodesign Challenge.
As a team, the students took an interest in the causes and environmental and humanitarian implications of the international water crisis. They wondered if they could take inspiration from biology/biotechnology and empower the communities most afflicted by this crisis by creating their own system for cleaning water.
Beginnings
From the beginning of the research process, the team investigated the incredible ways that bacteria and other microorganisms are employed to solve many of the challenges we are facing today.
Thanks to our newfound understanding of the laws that guide the life of many microorganisms as well as the emerging techniques used to hack the genetic makeup of these organisms like genetic engineering, we considered bacteria as good candidates for creating a long-term and inexpensive solution to the contaminated water crisis.
Cyanobacteria in wastewater management
Around the world, people have learned to use bacteria to treat contaminated water, and biological wastewater treatment has become the most common sanitation method.
This technology uses different types of bacteria and other microorganisms for the treatment and purification of polluted water before it is sent back into the environment. Bacteria used in this process are able to degrade the biological waste and use it as a source of energy to grow and multiply, effectively decontaminating the water for a safe return to the water cycle.
Some bacteria can be more effective than others though, and we discovered that established water-treatment facilities have not fully taken advantage of bacteria such as cyanobacteria.
Cyanobacteria are photosynthetic oxygen-producing bacteria that live in a wide variety of moist soils and water either freely or in a symbiotic relationship with other organisms. They are able to grow in large quantities and thrive just from sunlight, carbon dioxide, and minerals. This opens up sustainable water purification techniques in rural communities without needing expensive recourses.
Several strains of cyanobacteria are capable of producing what is called 'extra-cellular polymeric substances' or EPS. EPS-producing cyanobacteria have been proven to remove heavy metals from polluted waters and have been proven to promote coagulation. This means that the colonies of cyanobacteria that have absorbed dangerous heavy metals float, making them easier to be removed from the water.
Organisms like cyanobacteria can also be easily farmed in inexpensive vessels called photobioreactors. These vessels create the perfect environment for these cyanobacteria to generate biomass from light and carbon dioxide for long stretches of time. Farming cyanobacteria could create a long-term and inexpensive solution to the water decontamination problem that has afflicted so many people in the world.
Concept
The team began to imagine that we might one day be able to provide cyanobacteria to remote villages and teach local farmers how to farm them.
Once rural communities in desperate need of help have the basic tools and knowledge, they will be able to take advantage of an inexpensive and long-term solution to decontaminate unsafe drinking water and could manage on their own without constant international aid.
In order to achieve this, we need to select suitable strains of cyanobacteria with a few criteria:
fast-growing
able to grow over a wide range of heavy metals
able to produce EPS
able to be genetically modified
If the cyanobacteria can be genetically modified, they can be engineered to better absorb heavy metals in their cell walls, to create EPS with higher bioabsorption rates, and could even create ideal environmental conditions in the water to kill pathogens.
Project
Our team has conceptualized a speculative, non-profit company called “Clean Water of Our Future”.
The company provides innovative solutions for the decontamination of water to villagers and farmers living in rural communities around the world. Our first product is a treatment consisting of a unique blend of genetically engineered cyanobacteria designed for the bio-purification of contaminated water.
This simple 2-step treatment has the power to absorb heavy metals and dangerous pathogens from polluted water, making it safe to drink. We provide the villagers with small and hermetically sealed packages containing different strains of cyanobacteria serving different bio-remediation functions. The Cyanobacteria are dried, packaged, shipped, and become the starting bacterial culture for rural communities in need around the world. The starter colonies are then farmed in ready-to-assemble photobioreactors made of simple and inexpensive materials. Villagers will use the self-grown cyanobacteria colonies to clean large amounts of drinking water for the community.
The cyanobacterial culture can be farmed by anyone in the photobioreactors, creating a long-lasting, inexpensive, and self-governing way to clean water contaminated by heavy metals and dangerous pathogens. This is made possible by community educational programs and custom-designed photobioreactors, providing both the perfect living conditions for the cultures and creating new opportunities for farmers and villagers in rural communities.
Once grown, the colonies can be introduced inside water containers that are already used by the villagers like communal water tanks or Jerrycans. First, the cyanobacterial colonies are in charge of the absorption of heavy metals and the purification of dangerous bacteria. Then, the second colony will help flocculate the previously introduced strains and other dirt particles making them float to the top of the container for easy disposal.
The cyanobacteria colonies are fast-growing, can thrive over a wide range of heavy metals concentrations, and are genetically engineered to absorb heavy metals within their cell structure, purifying the water from dangerous pollutants.
Conclusions
Introducing bacterial farming practices in rural communities can become a long-term and inexpensive practice. This may not only decontaminate water sources, but with the right strains of cyanobacteria, could also be used for the production of food, energy, and biofertilizers. There's a lot left to learn about bacterial farming and its potential uses in society, but because of the minimal nutrition requirement of cyanobacteria, it can be proposed as an environmentally friendly practice.
Concerns
Cyanobacteria are known to produce a wide range of toxic secondary metabolites commonly called cyanotoxins. These could cause damages to the lungs or irritate the skin. Much research has been done on toxins and scientists are optimistic that it can be solved by genetically modifying the strain or introducing a secondary organism that could remove the contaminants.
The solution to this lies in more scientific research and prototyping, as well as a practical educational program introduced alongside our product to ensure long-lasting effectiveness.
Final thoughts
By working on projects like this, our team has learned about other countries and their stories. We’ve learned how to work together and learned about new topics. The students became more outgoing and empathetic, and perhaps most importantly, that they can investigate their passions and social issues by designing a project.
With their newfound knowledge, even as teenagers, they now know that they have the potential to impact the world.
