Biosand Filtration

Summary

This webinar presentation by Harvard's Engineers Without Borders chapter introduces BioSand filters, a cost-effective solution for clean water in developing regions. Highlighting their health benefits, adaptability, and sustainability, the talk covers the technology's functionality, effectiveness in pathogen removal, and long-term maintenance. The presentation also discusses the importance of community engagement and proposes a pilot project in Mukha Thani, Tanzania, to assess the system's practicality and impact on health and education.

Takeaways

• 🌟 BioSand filters are part of the humanitarian efforts by the Harvard Engineers Without Borders chapter to provide clean water solutions.
• 🧬 These filters are significant for health benefits, removing pathogens and improving the well-being of users in areas with a high need for potable water.
• 🌐 BioSand filters are adaptable and can be constructed using local resources, making them suitable for various regions.
• 📈 There is a substantial global demand for these filters, with over 650,000 in use across more than 70 countries, benefiting over 44 million people.
• 🚰 In communities like Lausanne, Chezj, and Mukesh Honey, access to potable water is limited, and BioSand filters can be a viable solution.
• 🔬 BioSand filtration works by using a biological layer to eliminate pathogens and a sand layer to trap contaminants, achieving high removal rates for bacteria and viruses.
• 💰 The filters are cost-effective, typically costing under a hundred dollars, and can serve up to seven people for about ten years before needing replacement.
• 🔧 However, they require technical expertise to build and have limitations, such as not removing all chemicals and requiring constant water resupply to maintain the biological layer.
• 🔄 When compared to other filtration methods, BioSand filters excel at removing pathogens but are less effective against chemical contaminants.
• 🛠️ The construction process involves obtaining and purifying local materials, building plumbing, and creating a diffusion plate to ensure proper water flow and oxygenation.
• 🔄 Maintenance is crucial for the long-term success of BioSand filters, including regular water level checks, swirl and dump procedures, and eventual full replacements.

Q & A

What is the purpose of the BioSand filter presentation?

The presentation aims to educate about BioSand filters as part of the humanitarian library webinar series, discussing their benefits, functionality, and sustainability in providing clean water to communities in need.

Who are the presenters of the BioSand filter webinar?

The presenters are Anthony Bogota, a junior studying bioengineering at Harvard, and James Nathan Hanger, a mechanical engineering student also at Harvard.

What are the three main parts of the BioSand filter presentation?

The presentation is divided into an overview of BioSand filtration systems, a discussion about their functionality, and a discussion about the sustainability of these projects.

Why are BioSand filters considered important for certain communities?

BioSand filters are important because they significantly remove pathogens, improve health, are adaptable to local resources, and are in high demand in areas lacking access to potable water.

In which countries are BioSand filter projects currently being implemented?

The projects are being implemented in locations such as the Dominican Republic and Tanzania, specifically in areas like low Sanchez and muga Thani.

What is the approximate number of BioSand filters in use globally, and how many people do they benefit?

There are over 650,000 filters in use in more than 70 countries, benefiting over 44 million people.

How effective are BioSand filters in removing bacteria and viruses from water?

BioSand filters are highly effective, capable of removing up to 99% of bacteria and 85% of viruses.

What are some limitations of BioSand filters?

Limitations include the need for constant resupplying of water to maintain the biological layer, inability to remove all chemical contaminants, and the requirement of technical expertise to build them.

How does the filtration speed of BioSand filters compare to other methods like chlorination, membrane filtration, and ceramic filters?

BioSand filters have a moderate filtration speed of 25 to 75 liters per hour, which is slower than UV systems but faster than ceramic filters. Chlorination and membrane filtration have variable speeds depending on volume and pressure, respectively.

What is the biological layer, and how does it function in a BioSand filter?

The biological layer, or schmutzdecke, contains predatory bacteria and other microorganisms that attack pathogens. It forms within one to two weeks and can take up to 30 days to fully mature, playing a crucial role in the filter's effectiveness.

What are the key steps involved in the construction of a BioSand filter?

The construction involves determining the container, obtaining and purifying local sand and gravel, building plumbing for water flow, creating a diffusion plate, and placing the system in an accessible location.

What is the importance of monitoring and maintenance for the long-term success of a BioSand filter?

Monitoring and maintenance are crucial to ensure the water level remains optimal for the biological layer, to prevent clogging of pore spaces, and to maintain the flow rate, ultimately ensuring the filter's effectiveness over time.

What community engagement strategies are suggested for integrating BioSand filters into communities?

Strategies include conducting surveys to gauge interest, obtaining community approval, building units in areas most in need, teaching family groups and school staff on proper use and maintenance, and potentially involving students in maintenance responsibilities.

Can you provide an example of a successful BioSand filter implementation and its outcomes?

A case study from Banaue in the Dominican Republic showed that 90% of BioSand filters were still in use after one year, reducing fecal indicator bacteria by 84-88% and significantly decreasing the odds of diarrheal disease.

What are the next steps the Harvard chapter plans to take to utilize BioSand filters in the next three months?

The chapter plans to build a BioSand filter at Harvard to test its effectiveness, potentially build one in the community of Mukha Thani, and leave a survey form with the headmaster to track usage and maintenance, with the goal of scaling the model if successful.

What are the key takeaways from the BioSand filter presentation?

The key takeaways are that BioSand filters are cost-effective, beneficial for communities lacking clean water, the biological layer requires careful maintenance, and access to clean water can improve health and education metrics.