||Association for the Development of Pakistan
|Khurram Owais Shah
Joined: 07 Nov 2007
Last Visit: 09 Oct 2010
|Posted: Mon Feb 15, 2010 2:38 pm Post subject: AHD Filters Expansion
|Project: Expansion of ADP's funding for bio-sand water filters in Sindh
Partner NGO:Association for Humanitarian Development
Project Team: Mohsin Gadit, Laraib Mahar, Shozab Naqvi, Belal Mahfooz, Abdus Samad Parekh, Arslan Memon, Saad Khan
EC: Tarim Wasim, Faris Rahman
|Saad Halim Khan
Joined: 30 Apr 2009
Last Visit: 14 Apr 2010
Location: Karachi, Pakistan
|Posted: Fri Feb 26, 2010 5:21 pm Post subject: Answers to questions 3 and 4
I'm having some problems attaching the word document, so I've pasted the text of the document below.
Looking forward to meet on Sunday.
Saad Halim Khan
How does it work?
The filter is simply an optimised residence for the good microbes that eat up the microbes that cause diseases. The filter is designed to protect the good microbes in the sand which would be destroyed if the sand was allowed to be churned up or drained of water. They require a stable surface to live on with a constant supply of dirty water and oxygen to feed on. The sand in the filter provides an enormous surface area for them to live on and they multiply to fill this space. This takes two to three weeks to establish. In the mean time the water is far better than before even after a day or two.
The active biology assembles its self in a series of layers. The uppermost is called the schmutzdecke.
They effectively remove:
iron / sulphur bacteria (slimy deposits)
manganese (rust, stains, metallic tastes)
hydrogen sulphide (rotten egg smell and other gases)
heavy metals (leads)
silt and sediments
What is a biosand filter?
The biosand filter is an adaptation of the traditional slow sand filter, which has been used for community water treatment for hundreds of years. The biosand filter is smaller and adapted for intermittent use, making it suitable for households.
Water treatment is carried out by the sand inside the filter. The filter container can be made of concrete, plastic or any other water-proof, rust-proof and non-toxic material.
The concrete biosand filter typically uses a box about 0.9 m tall by 0.3 m square, or about 0.3 m in diameter. The filter box is cast from a steel mold or made with pre-fabricated pipe.
The container is filled with layers of sieved and washed sand and gravel (also referred to as filter media). There is a standing water height of 5 cm above the sand layer.
Similar to in slow sand filters, a biological layer of microorganisms (also known as the biolayer or schmutzedecke) develops at the sand surface, which contributes to the water treatment.
A perforated diffuser plate or basin is used to protect the biolayer from disturbance when water is poured into the filter.
How does the biosand filter remove contamination?
Pathogens and suspended material are removed from the water through a combination of biological and physical processes. These occur both in both the biolayer and within the sand bed.
What does the biolayer look like?
The biolayer is not visible.
Does the biosand filter remove all bacteria and viruses?
The biosand filter will remove over 95% of bacteria and 80-90% of viruses, if the filter is properly installed and used. In most cases, the amount of bacteria and viruses that pass through the filter will not be enough to make a healthy adult sick. Young children, the elderly, people living with HIV/AIDS and sick people are more vulnerable to the bacteria and viruses.
Will the biosand filter take out parasites?
Yes, 100% of parasites are removed, if the BSF is properly installed and used. Parasites include worms and protozoa.
Does the biosand filter remove salt from sea water? What about pesticides, industrial contaminants or other chemicals?
The BSF does not remove the salt in sea water. The BSF does not remove chemicals that are dissolved in the water, such as pesticides, industrial contaminants, or fluoride. Some changes to the filter are possible to help remove arsenic.
How is the biosand filter used?
Contaminated water is simply poured into the top of the filter on an intermittent basis. The water slowly passes through the diffuser, and percolates down through the biolayer, sand and gravel. Treated water naturally flows from the outlet.
How often can water be poured through the biosand filter?
You can pour between 1 to 4 batches into the filter each day, waiting at least 1 hour after all the water has been filtered before using it again. It is recommended to use the filter every day; however you can wait up to a maximum of 48 hours between batches.
How should water from the biosand filter be stored?
Safe storage means keeping your treated water away from sources of contamination, and using a clean and covered container. It also means drinking water from the container in a way so that people don't make each other sick. The container should prevent hands, cups and dippers from touching the water, so that the water doesn't get recontaminated.
The most important things are to make sure that it is covered and only used for treated water.
Why does the filtered water need to be disinfected? Isn't the filter enough?
Treating your water in the home is a process that requires several steps. Although the water may look clear after filtration, it is still necessary to disinfect it. The filter removes most, but not all of the bacteria and viruses.
Disinfection can be done by boiling, adding chlorine or using solar disinfection (SODIS).
How fast should the water flow from the biosand filter?
The flow rate of the filter should be no more than 0.6 litres per minute when it is completely full. If the flow rate is greater than 0.6 litres per minute, then the sand should be washed less. A flow rate that is less than 0.6 litres per minute is only a problem if it is too inconvenient for the user. If the flow rate is too slow, then the sand can be washed more.
What if the flow from the biosand filter is very slow?
A slow flow rate means that the top of the sand is plugged with dirt. The dirt should be removed using the swirl & dump maintenance:
1. Remove the filter lid
2. If there is no water above the diffuser, add about 4 litres (1 gallon) of water
3. Remove the diffuser
4. Using the palm of your hand, lightly touch the very top of the sand and move your hand in a circular motion; be careful to not mix the top of the sand deeper into the filter
5. Scoop out the dirty water with a small container
6. Dump the dirty water outside the house in soak pit or garden
7. Make certain the sand is smooth and level
8. Replace the diffuser
9. Wash your hands with soap and water
10. Set up the storage container to collect the filtered water
11. Refill the filter
12. Repeat the swirl & dump steps until the flow rate has been restored
The biolayer has been disturbed by the swirl and dump, but it will develop again over time. It is recommended to disinfect the filtered water during this time.
How often should the sand be replaced?
The sand never needs to be replaced. The sand is cleaned by the swirl & dump maintenance.
Will any material from the biosand filter dissolve into the water and cause a health problem?
No, the cement, sand and biolayer will not dissolve in the water or cause any health problems.
How is it made?
The nadi used for the filter must be 32 to 34 inches tall.
A hole is made for the pipe in the side of the nadi using a screwdriver and a suitable stone or hammer.
The bottom of the hole must be 20 inches above the ground.
A single piece of stiff flexible pipe 30 inch long, 1 inch diameter and with no splits in it is fitted through the hole with one end inside the nadi touching the bottom. It is put in place and the hole around the pipe made water tight with cement.
A water storage pot for the filtered water must be chosen. If it is a nadi with a tap it should be put up high enough for jug to go under its tap. Put this clean water storage nadi on enough bricks to make this possible. The filter nadi can then be put in place on enough bricks for the protruding pipe to be just above the top of the storage nadi.
Potato size washed stones are placed in a single layer one stone deep at the bottom of the nadi. The gaps between them form channels for the water to flow easily into the pipe.
Small washed stones are placed on top filling the gaps between the potato size stones.
Enough should be placed to prevent the next layer of gravel from falling through and blocking the gaps under the potato size stones or clogging up the pipe.
A thin layer of washed, dhal size gravel is then spread to form a level surface over the small stones.
A thin layer of washed seed size gravel in then spread to form a level surface over the dhal size gravel.
These drainage layers must not exceed 4 inches in total thickness or there will not be enough room for the main material, the sand.
Washed sand is then added to a level 5 inches below the level where the bottom of the pipe goes through the side of the nadi.
The mutca is taken and a single hole is drilled in it using a 3 or 4 inch nail with a right angle bend in it to form a handle. At first this is difficult work but after a few minutes the hole is made without the need to hit it through with a hammer. Most screw drivers make holes that are a bit too large so a nail is better. The hole should be on the bottom of the mutca about 4 inches to one side so as not to get blocked too frequently by debris settling in the mutca.
The mutca is then tied in place on top of the nadi with the hole in the mutca in line with the pipe coming out of the nadi. A stone is wedged between the mutca and nadi so that the hole in the mutca can be seen and it is easy to notice if the hole becomes blocked. String must be used to fix the mutca in place in order to protect the good microbes in the nadi from being disturbed.
A cloth is tied over the mouth of the clean water storage nadi in such a way that the cloth is over the protruding pipe. The water should not be flowing onto the cloth at all, as this would re-contaminate the clean water.
Once dirty water has been given to the nadi every day for two to three weeks the filter will function effectively so long as the sand is not disturbed. During this period the water will gradually improve. If the sand and stones were well washed, water can be improved a little by the filter even on the first day.
The nadi for storing clean water should be emptied every three days during this initial period while water quality is rapidly improving.
Pots for storing clean water should never be used for collecting dirty water.
When using a new nadi to make a filter it should be first checked for leaks which should be repaired using cement.
Never completely fill a new nadi or small cracks will develop. Only half fill it with water at first, then after two or three hours fill it completely and check for leaks.
If the filter gets too slow or stops working, remove the top few inches of sand from inside the nadi. Wash this sand with water in a bucket or bowl then put it back in the nadi. Make sure that the level of the sand in the nadi is restored to 5 inches below the bottom of the pipe where it comes through the side of the nadi.
When it becomes necessary to clean the sand in the filter it is good if there is another filter in the community that can be used for the two or three weeks it takes for the filter to build up its numbers of good microbes after being cleaned. Dirty water used for starting off a new or recently cleaned nadi can be put through the new one then through an established one if it is necessary to drink this water.
Can it be built by the villagers?
The project was designed to ensure project sustainability based on self-reliance in remote rural areas.
Material is simple, low cost, locally made (could also be self-made) and conveniently accessible. The tools (hammer, sieves) once purchased last long. and can be moved and used from place to place.
Nadi filter unit is very simple to assemble, operate and maintain. No special skills are required for assembling the unit or to run it for filtering water.
No energy (electricity/fuel) is required for assembling or operating Nadi water filter, making it more viable in remote rural settings like Jati.
Local villagers were trained as trainers to promote and support the use of Nadi filters in their own as well other villages in the area.
Self-help has been promoted through local CBOs, who motivated Nadi users to make some nominal contribution for having a Nadi water filter for their households/family.
Is it sustainable over long periods of time in terms of wear and tear?
There is no data available on the impact of wear and tear on the Nadi filter or on how long it lasts. Should a filter break down the people will be able to fix it because imparting training is also a part of the project.
What are the pros and cons of using a Nadi filter?
Low cost and easily available materials
Simple assembly, operation, and maintenance.
Few and common tools required for assembly.
No electricity/fuel required for assembly.
Can be easily transferred.
Is able to filter out most of the bacteria and viruses
The filter removes most, but not all of the bacteria and viruses.
The Bio Sand Filter's inability to handle high turbidity during monsoon seasons, where the high amount of rain and runoff greatly increase the turbidity. The high turbidity leads to increased particle deposition and decreased pore size. As a result, frequent clogging of mainly the top layer of the sand occurs, reducing the flow rate of the BSF greatly.
When was it invented and by whom?
The Bio Sand Filter was developed in 1988 by Dr. David Manz of the University of Calgary, Canada, in response to various issues that were brought to attention from previous water treatment projects. The issues the BSF had to face were higher flow rates than the traditional slow sand filter, effective pathogen removal, improve the taste and appearance of the water, allow for intermittent flow, and still provide an appropriate technology for the developing world.
Is research on Nadi filters public?
Yung, K. (2003). Biosand Filtration: Application in the Developing World. University of Waterloo.
Pincus, M. (2003) BioSand Pitcher Filter. MIT
Is the research objective and convincing?
Yes. Continuous research has resulted in improved models of the Bio Sand Filter. There have been various improvements made in these filters which have not been implemented in the Nadi filters that AHD is installing.
Which charitable organizations have used this product globally and what are their opinions?
Many charities are using the Biosand filter globally. A Google search for 'charities using Biosand filter' comes up with 2200 results. The Biosand filter is being used in various forms such as plastic, concrete, etc. as well as with other filtration technologies.
What are the non-Nadi filter alternatives to get access to clean water?
The Safe Water System (SWS) (household chlorination method) was developed in the 1990s in response to epidemic cholera in South America by the Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization (PAHO). The SWS has three elements:
Point-of-use water treatment by consumers with a locally-manufactured dilute sodium hypochlorite (chlorine bleach) solution;
Safe storage of treated water; and,
Behavior change communications to improve water and food handling, sanitation, and hygiene practices in the home and in the community.
To use the SWS, families add one full bottle cap of the solution to clear water (or 2 caps to turbid water) in a standard sized container, agitate, and wait 30 minutes before drinking.
A bottle of hypochlorite solution that treats 1,000 liters of water costs about $0.10 using refillable bottles and $0.11-$0.50 using disposable bottles, for a cost of $0.0001-$0.0005 (0.01-0.05 cents) per liter treated. Education and community motivation add to program costs.
Locally manufactured ceramic filters have traditionally been used throughout the world to treat household water. Currently, the most widely implemented HWTS ceramic filter is the Potters for Peace design, which is flowerpot shaped, holds about 8-10 liters of water, and sits inside a plastic or ceramic receptacle. The filters are produced locally at ceramics facilities, and then impregnated with colloidal silver to ensure complete removal of bacteria in treated water and to
prevent growth of bacteria within the filter itself. Numerous other locally-made and commercial HWTS ceramic filters are widely available in developed and developing countries. Most ceramic filter HWTS systems are based on a filter/receptacle model. To use the ceramic filters, families fill the top receptacle or the ceramic filter itself with water, which flows through the ceramic filter or filters into a storage receptacle. The treated water is then accessed via a spigot embedded within the water storage receptacle.
Locally manufactured ceramic PFP-design filters range in cost from $7.50-$30. Distribution, education, and community motivation can add significantly to program costs.
Solar disinfection (SODIS) was developed in the 1980s to inexpensively disinfect water used for oral rehydration solutions used to treat diarrhea. In 1991, the Swiss Federal Institute for Environmental Science and Technology (SANDEC, EAWAG) began to investigate and implement SODIS as an HWTS option, to prevent diarrhea in developing countries. Users of SODIS fill 0.3-2.0 liter plastic soda bottles with low turbidity water, shake them to oxygenate, and place the bottles on a roof or rack for 6 hours (if sunny) or 2 days (if cloudy). The combined effects of UV-induced DNA alteration, thermal inactivation, and photo-oxidative destruction inactivate disease causing organisms.
SODIS as a virtually zero-cost technology faces marketing constraints. Since 2001, local NGOs in 28 countries have disseminated SODIS through training of trainers, educating at the grassroots level, providing technical assistance to partner organizations, lobbying key players, and establishing information networks.
The Procter & Gamble Company (P&G) developed PUR Purifier of Water in conjunction with the Centers for Disease Control and Prevention. PUR sachets are now centrally produced in Pakistan, and sold to NGOs worldwide at a cost of 3.5 US cents per sachet. The PUR product is a small sachet containing powdered ferric sulfate (a flocculant) and calcium hypochlorite (a disinfectant). PUR was designed to reverse-engineer a water treatment plant, incorporating the multiple barrier processes of removal of particles and disinfection. To treat water with PUR, users open the sachet, add the contents to an open bucket containing 10 liters of water, stir for 5 minutes, let the solids settle to the bottom of the bucket, strain the water through a cotton cloth into a second container, and wait 20 minutes for the hypochlorite to inactivate the microorganisms.
Each sachet of PUR is provided to global emergency relief organizations or non-governmental organizations at a cost of $0.035 (3.5 US cents), not inclusive of shipping from Pakistan by ocean container. Transport, distribution, education, and community motivation can add significantly to program costs.
(Source: USAID and CDC)
What are the pros and cons of each?
Proven reduction of most bacteria and viruses in water;
Residual protection against contamination;
Acceptability to users because of ease-of-use;
Proven health impact;
Relatively low protection against parasites;
Lower disinfection effectiveness in turbid waters contaminated with organic and some inorganic compounds;
Potential user taste and odor objections;
Necessity of ensuring quality control of solution; and,
Concern about the potential long-term carcinogenic effects of chlorination by-products.
Proven reduction of bacteria and protozoa in water;
Acceptability to users because of the simplicity of use;
Proven reduction of diarrheal disease incidence in users;
Long life if the filter remains unbroken; and,
A low one-time cost;
Lower effectiveness against viruses;
Lack of residual protection can lead to recontamination if treated water is stored unsafely;
Variability in quality control of locally produced filters;
Filter breakage over time, and need for spare parts;
Filters and receptacles need to be regularly cleanes, especially when using turbid source waters; and,
A low flow rate of 1-3 liters per hour in non-turbid waters.
Proven reduction of viruses, bacteria, and protozoa in water;
Proven reduction of diarrheal disease incidence in users;
Acceptability to users because of the simplicity of use;
No cost to the user after obtaining the plastic bottles;
Minimal change in taste of the water; and,
Although SODIS does not have a chemical residual, recontamination is unlikely because water is served directly from the small, narrow-necked bottles with caps in which it is treated.
The need for pretreatment (filtration or flocculation) of waters of higher turbidity;
User acceptability concerns because of the limited volume of water that can be treated at once and the length of time required to treat water; and,
The large supply of intact, clean, suitable plastic bottles required.
Proven reduction of bacteria, viruses, and protozoa in water;
Removal of heavy metals and pesticides;
Residual protection against contamination;
Proven health impact;
Acceptable to users because of visual improvement in the water; and
Sachets are easily transported due to their small size, long shelf life, and classification as non-hazardous material for air shipment.
Multiple steps are necessary to use the product, which requires a demonstration to teach new users;
The need for users to have, employ, and maintain two buckets, a cloth, and a stirring device; and,
The higher relative cost per liter of water treated compared to other household water treatment options.
(Source: USAID and CDC)
Who implemented these alternatives and why?
The Safe Water System (household chlorination) has been implemented in over 30 countries with numerous partners using a variety of strategies, including:
Social marketing organizations, such as Population Services International (PSI), sell hypochlorite solution in 20 countries. Over 12 million bottles of hypochlorite solution, treating 12 billion liters of household drinking water, were sold in 2007.
Local organizations use the social marketed hypochlorite solution in their own programming to provide safe drinking water. For example, in Western Kenya nurses are trained to use SWS water in hospitals and teach patients with diarrhea to use the PSI SWS product WaterGuard. In Uganda, people living with HIV are given WaterGuard to prevent opportunistic diarrheal diseases. In Kenya, schoolchildren are taught how and why to use the SWS, and school safe water clubs treat drinking water for all students. Also in Kenya, HIV self-help groups sell SWS solution and storage containers as an income generating activity.
Faith-based groups, such as the Jolivert Safe Water for Families program, make and bottle their own hypochlorite solution in rural areas. Local community health workers teach community members how to use the solution, make and distribute the solution, and follow-up with families to educate them on healthy water and sanitation practices.
Government ministries, such as the Ministry of Health in Guyana, work with local private companies to develop and market hypochlorite solution for emergency response.
SWS hypochlorite solution has been widely used to respond to emergencies from the 2004 tsunami in Indonesia to flooding and cholera epidemics in Africa.
Ceramic filtration programs have been implemented in over 20 countries using a variety of strategies, including:
Potters for Peace (PFP) is a United States and Nicaraguan-based non-governmental organization (NGO) that promotes the flowerpot ceramic filter design by providing technical assistance to organizations interested in establishing a filter factory. PFP has assisted in establishing filter-making factories in 17 countries. Once the filter factory is established, the factory markets the filters to NGOs who then incorporate the filter into their own water and sanitation programming. www.pottersforpeace.org
The first PFP filter factory, in Managua, Nicaragua, was constructed using private donations. From 1999-2005, the filter factory was a self-financed recognized micro-enterprise in Nicaragua. NGOs paid $10 per filter, and transported the filters themselves to project locations. Despite the fact that 23,000 filters were made and sold in Nicaragua from 1999-2004, the factory was not financially sustainable and was sold in 2005 to a private investor who increased the price of each filter to $17.
One of the largest ceramic filtration programs is in Cambodia, where two NGOs both worked with PFP to establish filter factories. RDI distributes the filters through unsubsidized direct
sales, distribution through local vendors, and community-based subsidized programs. IDE distributes the filters nationally through vendors. Both NGOs sell filters to government agencies
and other NGOs. The project has successfully distributed over 200,000 filters and has been extensively studied.
Over 2 million people in 28 developing countries use SODIS for daily drinking water treatment. Experience has shown that SODIS is best promoted and disseminated by partner institutions based in the project area. Important partners are community-based organizations (CBOs) such as womens clubs, youth associations or self-help groups, well-established NGOs working on community development projects, institutional organizations such as health posts, hospitals, and teacher training centers, and government programs. Individuals, such as community and religious
leaders as well as politicians and decision-makers, play a key role and should be involved from the beginning of a project. SODIS promotion in a new area begins with a pilot project of one year that reaches 2000-4000 families. In the second year, the project expands into the field of advocacy to scale-up the project. Examples of SODIS projects include:
The CBO KWAHO promotes SODIS in the Kibera slums of Nairobi, Kenya. Over 250,000 people are reached by trained promoters using social marketing to disseminate knowledge about
SODIS. Research-based information is given out by promoters to potential users, especially when users are skeptical about SODIS.
In Latin America the promotion is channeled through a regional reference center, Fundaηion Sodis. The Fundaηions strategy is to build and strengthen a network of partner institutions. The
Fundaηion does not implement projects, but focuses on training trainers, technical assistance, and lobbying activities. More than 100,000 people are using SODIS in Latin America.
In Assam, India, Assam University provided technical and training support for a SODIS promotion project with a local NGO. The dissemination phase targeted 20,000 households based on lessons learned during the pilot phase. An approach involving active participation of institutions such as village councils, schools, and health centers was adopted to ensure the project is community owned and sustainable.
85 million sachets of PUR, treating 850 million liters of water, have been distributed in emergency response or sold through social marketing projects in 2003-2007. PUR has been made available in 23 countries with numerous partners using a variety of strategies, including:
Social marketing organizations, such as the NGO Population Services International (PSI), sell PUR sachets in 9 countries.
Local organizations use the socially marketed PUR sachets in their own programming to provide safe drinking water. For example, in western Kenya students in schools are taught how and why to use PUR, and safe water clubs treat drinking water for all the students. Also in Kenya, HIV self-help groups sell PUR sachets and storage containers as an income generating activity.
PUR sachets have been widely used to respond to emergencies from the 2004 tsunami in Indonesia to flooding in Haiti to cholera epidemics in Africa.
The Procter & Gamble Childrens Safe Drinking Water program has been given numerous awards, including the Ron Brown Presidential Award for Corporate Leadership in 2007, the EPA Childrens Health Excellence Award in 2007, the Grainger Challenge Bronze Award in 2007, and the Stockholm Industry Water Award in 2005.
(Source: USAID and CDC)
Saad H. Khan
Joined: 16 Feb 2010
Last Visit: 03 Mar 2010
|Posted: Wed Mar 03, 2010 5:53 am Post subject: Project Proposal
Here are the initial proposal docs for your reference.
Joined: 16 Feb 2010
Last Visit: 03 Mar 2010
|Posted: Wed Mar 03, 2010 6:08 am Post subject: Trying again
|Let's see if this works
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