Biosand Filtration
Summary
TLDRThis 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
- đ BioSand filters are part of the humanitarian efforts by the Harvard Engineers Without Borders chapter to provide clean water solutions.
- 𧏠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.
- đ BioSand filters are adaptable and can be constructed using local resources, making them suitable for various regions.
- đ 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.
- đ° In communities like Lausanne, Chezj, and Mukesh Honey, access to potable water is limited, and BioSand filters can be a viable solution.
- đŹ 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.
- đ° 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.
- đ§ 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.
- đ When compared to other filtration methods, BioSand filters excel at removing pathogens but are less effective against chemical contaminants.
- đ ïž The construction process involves obtaining and purifying local materials, building plumbing, and creating a diffusion plate to ensure proper water flow and oxygenation.
- đ 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
đ 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.
đ ïž 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.
đŹ 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.
đ 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.
Mindmap
Keywords
đĄBioSand filters
đĄPathogens
đĄSustainability
đĄAdaptability
đĄHealth benefits
đĄWater quality
đĄBiological layer
đĄFiltration capability
đĄMaintenance
đĄCommunity integration
đĄCase study
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
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