 One in three human, globally, does not have access to safe drinking water. It is still one of the leading causes of death in the world. This is an incredibly simple solution. Using only sand, combined with bacteria, you can make drinking water. I present to you the Bioson filter. An open-source and low-tech system invented by the doctor David Mans in the early 90s. His organization, The Coast, has widely shared its expertise to other organizations for the benefit of millions of people. We have been in Nicaragua to meet one of them, Blue Energy. At Lotec Lab, we travel the world to find the best low-tech inventions that are useful, sustainable and accessible to all. Smell-Dactyls are the benefits of the arena filter. Well, the benefits of the arena filter are many, many times. It is a low-cost technology. It also purifies 100% the water, eliminating the bacteria and fecal coliforms. The study that was done here in the city determined that more than 99% of children are contaminated with coliforms. This problem has been generating from many years ago due to the population growth and the bad practices that we do as people. We do not have a potable water system, nor a water system for gray and black waters. So everyone tries to solve their problem with their abilities. This has a lot of problems because all the bacteria contaminate the surface layer. These bacteria go to the ground and then, therefore, they go to the wells. What is this filter? How does it work? It is quite simple. We have the reservoir where the water is applied. It filters a bucket of water, which is 20 liters of water. It is a period of half an hour or 45 minutes. It is a slow filtration, but at the same time not so slow. It supplies enough water for consumption and also for some other things that it does like cooking. The arena filter lasts 30 years. That is why we say that it is a technology of very low cost due to its duration time. The materials are completely organized. We find them in our locality. It is easy to replicate once you have the mold or in Blue Energy. What is the Blue Energy mission? Well, Blue Energy has been here for 16 years on the Caribbean coast and began implementing renewable energy projects. But in 2008, it opened its program for water supply and hygiene. With the Viva Arena filter, Blue Energy has all the equipment and the technical personnel for the implementation, more than everything, in the process of building the filter. Then, the beneficiaries are identified. These beneficiaries go to a workshop or a capacity where they are explained the entire process of use and construction of the Viva Arena filter. A member of the family supports the construction in the sand floor, in the preparation of the molds, in the mix, in itself, in the entire construction process. Do you think that this filter can be replicated in other countries in the world? Of course, this is just a model. There are many designs, many models that can be replicated in communities that present very similar problems to ours, to eliminate those biological bacteria that affect our health. There are many studies that show that it is very replicable in many cities that can change that reality, where they also have many problems of flowing rivers and contaminated lakes. I love this technology. It's cheap, robust and really efficient. But even if it seems easy, you have to be rigorous. I encourage you to follow a training program. Here is how it works. The dirty water is poured into the reservoir. It flows gently through the diffuser to protect the sand surface. The sand mechanically filters dirt and big particles from the water. The bio layer is the active part of the filter. This is where good bacteria kill the pathogens. Then the water flows through the separation and the drainage gravel. They prevent sand from clogging the outlet pipe. Water that comes out of the outlet pipe is safe to drink. To make it, you will need... Construction sand avoids sand from beaches or rivers. Separation gravel. Drainage gravel. Add blue energy, thereby bulk gravels and sieve it. A food grade container, 90 cm long. Concrete is too heavy for the boat. So we did it with the 10 cm diameter PVC pipe. This surface is good to filter 1.5 liters at a time. At blue energy, the surface is 13 times bigger in order to filter 20 liters at a time. Outlet pipe on fillings, diffuser and taps for the big pipe. Safe water storage container. At the bottom of the filter, there is a pipe to drain the water. Glue the cap with PVC cement at one end, the pass hole at the other end. Drill small holes. Drill a hole at the bottom of the body. Pass the outlet through the body. Connect the elbow, the pipe and the two last two elbows. Fix the outlet pipe to the body. Glue a cap at the bottom of the body. In this step, we'll fill up the body with 7.5 cm of drainage gravel. 5 cm of separation gravel. 55 cm of sand and water up to the level of the outlet pipe. Wash the gravels until the water is clear. Pour 20 cm of water. When you add the gravel and sand, it will help to remove the air. Fill the bottom with the drainage gravel up to 7.5 cm. Add a 5 cm layer of the separation gravel. Wash the sand 3 or 4 times, although the water doesn't have to be clear. The efficiency will depend on the size of the sand. If you wash it too much, the flow will be too fast. Pour sand. Make sure there is always water above the sand. Stop when it remains 5 cm between the surface of the sand and the outlet. The water level has to reach the outlet. Place the diffuser 10 cm from the top. Put a lid. Fill it up to the edge. If the flow stops in less than 30 minutes, that means you wash the sand too much. Just redo it. If the water is not clear in the beginning, don't panic. The bio layer takes about 30 days to fully develop. During this period, pour water every day, but don't drink it. After 30 days, if possible, test your filtered water in a laboratory to check it. Use water that is as clean and safe as possible. It's a living system, so you have to fill the filter regularly to keep the good bacteria alive. Respect a gap of minimum 1 hour and maximum 48 hours between 2 fillings. Over time, the bio layer adapts itself to a certain quality of water. If you want to use a different source, wait for a couple of days until you drink it. So the bio layer can adapt to the new pathogens. When properly used, it's a great technology. I like the idea that we use microorganisms to do such an important job. Another example showing that to rely on nature is efficient, sustainable and accessible to all. The goal of the Lottec Lab is to find Lottec innovation, document and promote them so that anyone can replicate them. It's open source and collaborative, so feel free to comment and if you make it, share it with us.