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.

Outlines

00:00

🌍 Introduction to BioSand Filters and Their Global Impact

This paragraph introduces the BioSand filter as part of a humanitarian webinar series by the Harvard Engineers Without Borders chapter. The presenters, Anthony Bogota and James Nathan Hanger, provide an overview of the BioSand filtration system, its functionality, and sustainability. They emphasize the health benefits of the filters, such as pathogen removal, and their adaptability to local resources. The need for such technology is highlighted, particularly in low-income areas like Sanchez in the Dominican Republic and Muga Thani in Tanzania, where access to potable water is limited. The paragraph also discusses the popularity and effectiveness of BioSand filters, which are used in over 70 countries and benefit over 44 million people, including their ability to significantly reduce the incidence of diarrheal diseases.

05:04

🛠️ Components and Functionality of BioSand Filters

This section delves into the components of a BioSand filter and how it functions. The filter consists of a lid, diffuser, biological layer, filtration sand, separation and drainage gravel, and an outlet tube. The biological layer, or schmutzdecke, is crucial for the filter's effectiveness, containing predatory bacteria and other microorganisms that attack pathogens. The sand layer traps contaminants, and the entire system is designed to ensure water flows through these layers for purification. The paragraph also covers the construction process, including selecting a container, obtaining and purifying local sand and gravel, building plumbing, and creating a diffusion plate. The importance of maintaining the water level and the biological layer is stressed, as is the need for regular maintenance to prevent clogging and ensure the filter's continued effectiveness.

10:04

🔬 Sustainability and Maintenance of BioSand Filters

The focus of this paragraph is on the long-term sustainability of BioSand filters. It discusses the importance of monitoring and maintaining the biological layer to ensure optimal water levels and prevent bacterial die-off. Regular maintenance, such as the 'swirl and dump' method, is necessary to dislodge dirt and maintain flow rates. Full system replacement is recommended every 10 years. The paragraph also addresses the need for community approval and involvement, suggesting surveys and discussions to gauge interest and willingness to maintain the filters. A pilot system is proposed to assess the community's acceptance and use of BioSand filters. The case study of Banaue in the Dominican Republic is highlighted, showing high usage rates and significant health improvements due to the filters.

15:06

📈 Conclusion and Future Steps for BioSand Filter Implementation

The final paragraph concludes the presentation by summarizing the key takeaways about BioSand filters. It reiterates the cost-effectiveness and health benefits of the filters, especially in communities that lack access to clean water. The biological layer's maintenance challenges are acknowledged, but its advantages over other filtration methods are also highlighted. The paragraph outlines potential next steps for the Harvard chapter, including building a BioSand filter at Harvard to test its effectiveness, followed by implementing one in the community of Multani and conducting follow-ups to assess usage and maintenance. The ultimate goal is to scale the model if proven successful, with the community taking over the construction and maintenance of the filters.

Keywords

💡BioSand filters

BioSand filters are a type of water filtration system that uses a combination of biological processes and physical filtration through sand layers to remove pathogens and improve water quality. In the video, they are highlighted as an important technology for providing clean water in areas like low Sanchez in the Dominican Republic and Muka Thani in Tanzania, where access to potable water is limited. The script mentions that these filters can significantly improve health by removing pathogens and are adaptable, using locally available resources.

💡Pathogens

Pathogens are disease-causing microorganisms such as bacteria, viruses, and parasites. In the context of the video, BioSand filters are effective at removing up to 99% of bacteria and 85% of viruses, which are types of pathogens. The reduction of these pathogens is crucial for improving the health of individuals in communities where the filters are implemented, as it can lead to a decrease in waterborne diseases.

💡Sustainability

Sustainability in the video refers to the long-term success and maintenance of BioSand filter projects. It encompasses the ability of these systems to continue providing clean water over time without requiring excessive resources or maintenance. The script discusses the importance of monitoring and maintenance, such as regular water addition and the replacement of sand and gravel layers every 10 years, to ensure the filters remain effective.

💡Adaptability

Adaptability in this context means the ability of BioSand filters to be modified or used in various environments and conditions, utilizing local resources. The script mentions that these filters are adaptable, which is a key benefit as it allows them to be implemented in different areas, such as the Dominican Republic and Tanzania, using materials that are readily available in those regions.

💡Health benefits

The health benefits mentioned in the video are the positive impacts on individuals' health resulting from the use of BioSand filters. By removing pathogens from water, these filters can significantly reduce the incidence of diarrheal disease by 50 to 75 percent. The script emphasizes the importance of clean water for improving the overall health of communities in areas where potable water is scarce.

💡Water quality

Water quality refers to the condition of water in terms of its suitability for use, including the absence of contaminants and pathogens. The video discusses how BioSand filters can improve water quality by killing pathogens and trapping contaminants in the sand layers. The script provides an example of the effectiveness of these filters in reducing bacteria and viruses, which directly contributes to better water quality.

💡Biological layer

The biological layer, also referred to as the schmutzdecke in the script, is a critical component of the BioSand filter. It is a layer of predatory bacteria and other microorganisms that attack and consume pathogens. The script explains that this layer takes about one to two weeks to form and is essential for the filter's effectiveness in removing bacteria and viruses from the water.

💡Filtration capability

Filtration capability refers to the ability of a system to remove contaminants from water. The script discusses the BioSand filter's capability to remove up to 99% of bacteria and 85% of viruses, highlighting its effectiveness. However, it also notes that the filters are less effective at removing chemical contaminants, such as salt and fluoride.

💡Maintenance

Maintenance in the context of the video pertains to the regular care and inspection required to keep the BioSand filters functioning properly. The script describes specific maintenance tasks such as the 'swirl and dump' method to clean the filter every four to six months and the full replacement of the system every 10 years, which are crucial for the long-term sustainability of the filters.

💡Community integration

Community integration is the process of involving and engaging the local community in the implementation and use of BioSand filters. The script suggests building filters in areas most in need and educating community members on proper use and maintenance. This approach ensures that the filters are not only effective but also embraced and sustained by the communities they serve.

💡Case study

A case study, as mentioned in the video, is an in-depth analysis of a specific instance or situation, in this case, the use of BioSand filters in Banaue, the Dominican Republic. The script uses this case study to illustrate the real-world effectiveness and sustainability of the filters, showing that 90% of the filters were still in use after one year and significantly reduced fecal indicator bacteria.

Highlights

BioSand filters are presented as a crucial part of the humanitarian library webinar series by Harvard's Engineers Without Borders chapter.

Anthony Bogota and James Nathan Hanger introduce themselves as presenters, representing bioengineering and mechanical engineering backgrounds respectively.

The presentation is divided into three parts: an overview of BioSand filtration, functionality discussion, and long-term sustainability of the projects.

BioSand filters are highlighted for their health benefits, adaptability, and significant need in certain locations such as the Dominican Republic and Tanzania.

Over 650,000 BioSand filters exist in more than 70 countries, benefiting over 44 million people.

In Lausanne Chezj, two-thirds of the community lack access to potable water, indicating a dire need for filtration systems.

BioSand filtration systems are effective in removing up to 99% of bacteria and 85% of viruses, significantly reducing diarrheal disease incidence.

The cost of BioSand filters is under a hundred dollars, making them a low-cost, high-impact solution.

BioSand filters require technical expertise to build and do not remove all chemical contaminants from water.

Comparison with other filtration methods shows BioSand filters' effectiveness against pathogens but limitations with chemical contaminants.

The construction process of a BioSand filter involves determining the container, obtaining local sand and gravel, and building plumbing for water flow.

The biological layer, or schmutz deck, is critical for the filter's effectiveness and requires a maturation period of up to 30 days.

Maintenance of BioSand filters includes regular monitoring of the biological layer and periodic 'swirl and dump' to prevent clogging.

Community approval and integration are vital for the success of BioSand filter projects, with suggestions for pilot systems and community education.

A case study from Banaue, Dominican Republic, shows high continued usage and significant health benefits from BioSand filters.

The chapter plans to build a BioSand filter at Harvard, conduct water quality tests, and potentially scale up the project in communities like Mukha Thani.

Key takeaways emphasize the affordability, effectiveness, and health impact of BioSand filters, as well as the importance of community engagement.

Transcripts

hello in this presentation we'll be

going over BioSand filters as part of

the humanitarian library webinar series

done by the Harvard C's engineers

Without Borders chapter my name is

Anthony Bogota I'm a junior studying

bioengineering at Harvard

my name is James Nathan hanger I'm a

mechanical engineering student junior at

Harvard for our presentation we'll be

splitting it up into three different

parts an overview of BIOS and filtration

systems discussion about their

functionality and then finally

discussion about the sustainability of

these projects essentially how to ensure

their success in the long term so first

talking about an overview of the project

so it's important to signify why BioSand

filters are important so they can

provide a variety of different health

benefits significantly removing

pathogens and improving the health of

individuals who use it they're very

adaptable so they can use resources from

a variety of different areas and which

are generally available there is a

significant need for this kind of

technology and the locations where we're

currently doing projects which would be

low Sanchez in the Dominican Republic

and muga Thani and Tanzania there's a

widespread demand for potable water that

in those areas these systems are also

very popular where over 650,000 filters

exist in more than 70 countries and

benefit over 44 million people so

specifically in the areas we're doing

projects in in lausanne chezj about

two-thirds of the community do not have

an access to potable water that amounts

to around 300 people while the wealthier

areas are do have access to central

piping some of them also do have bios

and filtration systems so we know that

this is an option that has been

considered in this community already in

terms of mukesh honey the only potable

water available is located at the

faraway borehole

which makes it pretty in it and

accessible to students and teachers who

need to spend a lot of time in the

community during the day for classes and

there are no filtration systems in the

community the rainwater catchment

systems that are currently being worked

on at this time will alleviate the need

however this water will still not be

filtered so it's important to find a

filtration system that could do this so

giving a general overview of bio sand

filtration systems they can improve

water quality such as by killing

pathogens through predation of

microorganisms in their biological layer

or schmoozed a key contaminants and

pathogens can also get trapped in sand

layers due to small spaces in the grains

of sand and these systems are actually

very effective they're able to remove up

to 99% of bacteria and 85% of viruses

and they're also able to reduce the

incidence of diarrheal disease by from

about 50 to 75 percent these are really

great because they're low cost and high

impact they can use local materials and

they generally cost under a hundred

dollars when looking at the long term

these things can serve up to seven

people and take about ten years before

they need to be fully replaced however a

drawback of these systems includes

constant resupplying of water to

maintain the biological layer they don't

remove all chemicals in the water or

viruses and they require technical

expertise to build when comparing a bios

and filtration system to other methods

we can see that it's very effective at

getting rid of pathogens such as

bacteria and protozoa however it's much

less effective at dealing with chemical

contaminants such as salt and fluoride

chlorination is very effective at

getting rid of bacteria however it's not

as effective when dealing with viruses

and it has a significant problem with

taste where many in

vigils who drink chlorinated water don't

like the taste and will sometimes refer

not to even chlorinate their water on

account of that membrane filtration

systems are very effective at dealing

with various contaminants however they

require the most frequent maintenance UV

systems on the other hand are also very

effective against microorganisms however

these systems require electricity and

are not able to get rid of physical

contaminants or reduced your vidi

ceramic filters are very effective

against most contaminants however they

have a very slow filtration rate and

they need to be replaced every one to

two years in terms of filtration speeds

BioSand filters have a in moderate

filtration speed in that it can take or

they can flow out about 25 to 75 liters

per hour

UV systems however are the fastest

--fill filters available where they can

do about 60 to 180 liters per hour

ceramic filters have the slowest flow

rate of one to two liters per hour

chlorination depends on the volume and

membrane filtration depends on the

pressure however the flow rate can be

comparable to UV all right so now we'll

talk about the functionality of BioSand

filters so just as a quick overview

there are many components to a BIOS and

filter it starts at the very top where

the lid covers up the BIOS and filter

from Xtranormal contaminants the

diffuser is effectively a perforated

plate that prevents incoming water

that's placed in the BIOS and filter

from disserving the layers below and

distributes the water across the entire

surface area the Bizon filter the bio

layer or Schmidt Steinke then is that

has the predatory bacteria and that

attacks the pathogens and what's not

caught in the bio layer and the other

contaminants are then passed through the

filtration sand where almost all of it

gets trapped the separation and drainage

gravel then facilitate the water flow

and it ultimately comes out of the

outlet tube and is either stored in a

safe water storage contain

or simply has a tap on the end so the

general process then is that dirty water

is poured in it hits the diffuser plate

it trickles through onto the schmutz

tacky by later through the diffuser

plate it rests there and ultimately it

passes through the sand column and then

it goes up and out the system now a

little bit more specifically about the

biological layer which would segi so it

contains food chains of ciliated

protozoa which are free and and free

living bacteria amoeba crustaceans algae

and other microorganisms typically this

would Zack you will form in about one to

two weeks but ultimately it could take

up to 30 days to fully mature and

treatment efficiency unfortunately is

limited during the first two weeks but

it's difficult to predict exactly how

quickly it will develop the most

difficult part is that it's not visible

so there's no way to definitively know

when the schmoes ecchi is fully

developed unless you have proper water

testing equipment which in many cases

the local community will not have so

ideally with Deki development time and

that varies based on the local water

conditions will be tested and

established whenever those filters are

implemented and so then the community

will know roughly the time that it takes

based on those local conditions for the

future and then the sand layer more

specifically is genuinely between twenty

to thirty inches thick the exact

thickness will vary based on your

container size grain size has been found

to not have a particularly large effect

on filtration capability but a rough

guideline is 0.35 millimeters in

diameter for grain size and ultimately

you want to make sure that that sand is

properly cleaned and filtered before

it's actually placed in the bio sand

filter so that new contaminants aren't

introduced into the system so then for

the construction process the first step

is determining what container you have

in general BioSand filters are made out

of a plastic drum such as the 55 gallon

one depicted in this picture or a

concrete column boat specifically for

the five cent filter

then local sand and gravel needs to be

obtained ideally from a quarry so that

it's not contaminated for example sand

often available in a riverbed will often

have biological or other contaminants

then these in gravel should be purified

now this is time and water intensive but

it is very important to sift through it

and to flush it off with many layers

with many passes of water so that you

can ensure that it's relatively pathogen

free then you need to build plumbing to

enable water to flow from the bottom of

the unit to the top you want to ensure

that the spout is slightly above the

standing water level so that you can

ensure that there's always that water

covering the shindeki to ensure that the

bacteria have the ability to diffuse

oxygen through the water but never get

dehydrated and then you want to create

the diffusion plate at the top which you

can effectively just cut holes into a

special plate or even just use the lid

of the tank that you're using and then

finally you want to place the system in

a accessible location and ideally you

would have built it in the proper

location right away simply because it

does get heavy with the sand and gravel

and then water in the system all right

move on to the last portion of our

presentation which is looking at

sustainability of the project

essentially ensuring the long-term

success of using a bio sand filter

so first talking about monitoring and

maintenance it's very important to

monitor the biological layer in order to

ensure that the water level remains

around five centimeters the tolerance

can be it's not very well defined but

it's around plus or minus one centimeter

so four to six centimeters should be all

right there's a risk of bacteria dying

from dehydration if the levels of the

water are too low or lack of oxygen

levels are too high where the gas does

not reach the surface of the sand

underneath of water which can

two bacteria from growing on that

surface as in terms of need of

maintenance the pore spaces between San

Ogawa can get clogged by contaminants or

growth of microorganisms and can reduce

the flow rate over time the filter will

still function at the slow brillo rates

but people might stop using it

continuing on with monitoring and

maintenance so every four to six months

it will be important to do a swirl and

dump where the spout of the system is

blocked and the diffuser plate is

removed from there water will be served

by hand and then what are we poured out

carefully dislodge the dirt and the TOC

layer without damaging the biological

air or shmoo stankin every 10 years it

will be important to do a full

replacement of the system where all the

sand and gravel is removed and replaced

with fresh and sifted layers however

this will destroy the shmoo stack a

biological layer which will then where

you grow and it's important to

consistently add water at least once

every two days to maintain the water

level above the shmoo stick it and then

it would it's ideal to scrub the

diffuser plate lid and outlet with water

in order to maintain the flow rate so

it's important to realize that even if

we conclude that BioSand filters are

beneficial for our communities we still

need the community's approval before we

go ahead with the project and low

Sanchez it would be a good idea to

conduct a survey of the homes without

BioSand filters to determine if they are

the preferred means of filtration but

also be good to talk to individuals who

have these systems already to see what

they think of them in mukha Thani it

would be good to show images and plans

to the headmaster and the teachers and

determine if they would be willing to

maintain a pilot or test BIOS and filter

with the possibility of creating more in

the future

this pilot system would essentially be

useful to figure out whether or not the

community will use this system and if

they would like to continue using

in terms of community integration in lo

Sanchez we could build BIOS and filter

units in areas that are farthest away

from central piping and top stands that

also happened to be the poorest it would

also be really good to teach family

groups how to properly use these systems

and maintain them and a point point

people who are essentially in charge of

maintenance and mukha tani would be good

to build BIOS and filter units by each

primary building in the school complex

and then to teach the headmaster and

teachers how to properly use and

maintain the system and suggest that

students could also share the

responsibility all right so now we

figured it would be useful to go through

a BIOS and filter case study to move

from the theorem to show how it's

actually been used in practice so we

decided to look at the famous example of

banaue in the dominican republic there

are a few studies conducted on this town

and ultimately 328 households were

interviewed between the two points of

being interviewed

90% of BioSand filters were still in use

after one year and according to many

fecal indicator bacteria tests done on

BIOS and filter households over that

time the fecal indicator bacteria were

reduced between 84 and 88 percent and

between households that use BSS and non

BSF households the odds of diarrheal

disease were just 0.3 9 so what are the

then the possible concrete next steps

that our chapter can take in the next

three months to utilize vsfs

and so the ultimate plan is to create

one at Harvard and conduct water quality

tests to demonstrate its effectiveness

or perhaps the lack thereof and we like

to test it on rainwater and then for the

ultimate test Charles River water which

is notoriously dirty and then if it's

shown to be effective the next step

would be to build one in the community

of Multani and to leave the headmaster

of that school

complex with a survey form to track

usage and maintenance frequency and we'd

like to periodically call community the

community which we already do but

specifically to followup on the success

in progress with bison filter and

hopefully if we see that it's being

regularly used and maintained we could

build more and live leave the community

with building instructions so that the

model could be scaled further and so

finally let's conclude with the key

takeaways of BioSand filters so first of

all they're cheap and effective although

in our communities they're already

available in lausanne chose both Mutiny

and los angeles could benefit from

increased proliferation of BioSand

filters and within them the biological

era Dishman Steinke is the most

difficult to maintain because it

requires constant water addition and the

water needs to be held at a constant

level but that allows them to provide an

advantage that other filtration methods

do not have and finally access to clean

water can help with a variety of health

and education metrics and so building

these systems in communities that need

them is incredibly important alright and

here are all of our various citations

thank you very much for following along

with this webinar please feel free to

peruse our sources for more information

and we hope that this is helpful for

your future projects thank you

you