The Water Filtration System

Transcription

1 The Water Filtration System The Hot Dogs Allan Fong ( ) Mukund Ragunathan ( ) Lewis Ballard ( ) Kim Junkyu ( ) Xiangnan Zheng ( ) Mohit Nimavat ( )

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3 Page3 Table of Contents Executive Summary... 6 Team Reflection... 8 By Allan Fong:... 8 By Lewis Ballard By Junkyu Kim By Mohit Nimavat By Zheng Xiangnan By Mukund Ragunathan Problem scope Technical Review Design Requirements: Cost effectiveness Effectiveness of solution Cultural and social acceptance Effects on environment Sustainability Design options Ultra Violet ( U.V.) Reverse Osmosis Activated Carbon Filter Ceramics... 29

4 Page4 2.5 Slow sand filter Solar Distiller Water storage solution: Ferro cement tanks for additional water storage Option Selection Summary of Design Detailed Description Functional Diagram Functional Description Bio Layer Pause Period Standing Water Layer Flowing Stage Activated Carbon Manufacturing procedure Materials: Wash the sand Manufacturing Ferrocement tanks: Implementation Plan Implementation Overview Logistics Educating the locals Fund Raising Component list... 53

5 Page Implementation Procedure STEP 1: FUND RAISING STEP 2: Manufacturing Filters STEP 3: Establishing Headquarters STEP 4: Recruitment STEP 5: Distribution of Filters STEP 6: Ongoing Maintenance Additional Uses Discussion Strengths and weaknesses of the design Next Steps Evaluation Supporting Documents Cost analysis: Conclusions Bibliography... 66

6 Page6 Executive Summary The team, Hotdogs have designed a solution for water filtration to improve the quality of living for the people in Mekong delta area in Vietnam. Through the research and considerations, it was decided to design a filtration system which was a combination of the slow sand filter and activated charcoal filter. The filter made by the team consists of three main components which consist of the diffuser, the slow sand filter and the activated charcoal filter. The cover is designed to temporarily contain contaminated water, pre-form, pre-filtering with a cloth and airate water. The slow sand filter separates organic materials and living micro-organisms from the water and finally the activated charcoal removes improves the taste of treated water. Providing filtered water by the team s product will help the people in Mekong delta area to live a healthy and efficient life. Long term consumption of contaminated water is harmful to humans, especially to infants under age of 5. The bore water and rainwater used by people in Mekong delta area contains micro-organisms, organic materials, and compounds. Therefore, what is required is a filter which completely removes impurities and is affordable for the local people. The filter works and is designed in such a way that it uses naturally available resources which means it is environmentally friendly and affordable. The materials used

7 Page7 in the design are a plastic drum, cylinder, pipes, activated charcoal, different sizes of sand and gravel. The cover of filter has a depth so it can hold water and there is also a cloth on the top surface to prefilter water, this will extend the life of the filter by removing large particles from entering the sand. The slow sand filter is made of separated layers of sand in the drum and a pipe at the bottom of the drum. The activated charcoal goes in the cylinder which has a hole on the top and at the bottom; the edge of a pipe is machined to be screw joint. The filtering ability is excellent and appropriate for the water source in Mekong delta area. Materials are sourced locally and are naturally available which means it is less costly to make and maintain and the best part of it all is that it works by gravity force. In the future this product designed of will be a fundamental product to any country. Countries of the third-world will be the most prospered but even the developed countries of the world can prosper from this invention. When research and development increase for this product, not only can it be used for humanity purposes; but it can also lead to a business success within the economic world.

8 Page8 Team Reflection By Allan Fong: The engineers without borders challenge provided a challenging and rewarding experience to apply skills gained from the lectures and tutorials in a real world situation. As a first year student, it was unexpected to be involved in a group project so soon. Teamwork is an essential skill in engineering, so it is good idea to make an early start in developing the skill. Participating in a real world project when developed ideas and solutions could benefit the lives of the less fortunate was a major motivation and was an enjoyable exercise. The idea of not having potable water available straight from the tap, made the team realise just how lucky it is to live in a developed country. With so many ideas, techniques had to be applied, such as trade off analysis to compare how realistic ideas are in the real world. It enabled the team to view ideas from many perspectives, which resulted in ideas being adopted, when at the beginning was not a first choice. From the progression of the project, the team has gained insight into many significant matters that determines a successful project. Communication skills have improved such as body language, speech, attentiveness, patience, and clarity. Teamwork skills were developed such as listening to each other s ideas, questioning and discussion, respecting each other, sharing and participating. It is apparent that each member of the team had their own pace, research techniques and writing style, such diversity made compiling the report a

9 Page9 complicated task. In effort to compile a report that was coherent and flowed smoothly, all members were responsible for proofreading and editing. Diversity lead the team to realise that to complete tasks effectively and efficiently, the strengths of each team member should be utilised for the best tasks suited. The challenge brought with it many obstacles which had to be overcome, in particular the following: Lack of concise and valid information about the area, which made it difficult to put into consideration their local culture, practices and social habits. A very low budget as part of the design requirement, which restricted the team s solutions. Time restraints, meeting at suitable times and place to discuss the project, frequent meetings had to be adopted to meet deadlines. Understanding the scope of work for each team member, expectations of team members to complete set tasks on time and at a high quality. As well as the obstacles, the challenge included many things that the team enjoyed which include: While there was a lack of information about the Anh Minh district, we enjoyed the opportunity to learn about its people and culture. Low budget constraints forced us to consider basic but effective designs and investigate material which would not normally be considered.

10 Page10 Team work provided opportunities to form friendship with new classmates and teamwork skills were developed. The knowledge and experience gained from working together will help greatly towards each team member s studies and future careers as engineers. By Lewis Ballard The engineers without borders design challenge has been a very interesting experience, one which I have learnt and developed a lot of group skills from. This challenge has been a great way to learn about another country and their ways of life and it showed just how lucky we are living in a developed country. Being put in a team and given a design project is something that is normally completely out of my comfort zone as I have never been in a proper team or team like situation. There are many skills that I have learnt from being in this situation such as effective communication, collaboration and organization. All these skills will be very valuable as I progress through my career and get put in different teams and are giving different tasks. Since we were looking to design a solution for a problem in another country we did a lot of research into that country and so learnt a lot about the different lifestyles that the people there live. One of the biggest differences was

11 Page11 the fact that these people don t even have access to clean drinking water which is something we take for granted and never really think about. This has been a great challenge as it has shown me the skills that I need to develop to become a valuable team member and it has also shown just how lucky we are to be living in this country with all the things we take for granted. By Junkyu Kim A project Engineers Without Border (EWB) gave students a special chance to work as part of a team and provided a good opportunity to improve teamwork skills. Through the project, the team have learnt several important things; clear communication skills, sharing responsibilities between individuals, and time management skill. Especially sharing responsibilities came to the team as a challenge and each team member will need to improve it more in the future. It was a good exercise that the project is based on a real world problem which generally happens in the world. This also made the team realise that the peace has not come yet in the world due to the essential problems which affect on life of people in developing countries and the problems should be solved for the better quality of life of all human beings. Through team working, the team learned how important each member of the team is. In comparison, the team is like a set of linked whiles. If one while is small and other is big, they cannot be used together otherwise they will not roll

12 Page12 well. Each team member will need to consider and try to improve skills and abilities to work well in a team. The team has learnt many important things from this project. Each team member have a few weaknesses which make the burden of team heavier. Each team member will need to train themselves to work well in a team. By Mohit Nimavat The E.W.B. or Engineers Without Borders challenge was one of a kind experience where all the theoretical knowledge merge with practicality and slowly transformed into a real life project. As an International student it opened various doors of oppurtunities, provided lessons on team dynamics and socialization. The grouping was done with a random process and combined to form teams. These teams were diverse and made us learn a lot about cultural diversity. The main driving force for the team was the lack of basic amenities in the Ahn minh District of Vietnam. It was decided that potable water one of the key features that should be focused upon and treated to provide efficient solution by the end of the term. This was a great chance for us aspirant engineers to have a head start towards tackling real life issues and coming up with feasible solutions. One major lesson that was learned was that the project develops on it owns. The initial product that we planned to generate was far away from the final product. Detailed analysis of the problem, consideration of cost and available materials and design flaws tend to modify the product.

13 Page13 This problem was mainly overcome as a team. The team HOT DOGS comprise was members from different nationalities. This brings various sets of skills and talent. Positively used it is a powerful weapon. This experience has enhanced each members soft skills as in, communication skills, leadership attitude to tackle issues etc. As each member was from a different country there was a bit of language rather accent barrier. It did not last long as we were accustomed to each other soon and helped each other improve in every step of the project. One of the most important skills acquired in this journey was team player. Everything that is done in the team or by the team is not always favourable, but sometimes some sacrifices have to be done for teams sake. All decisions would not be as per our wish. Team s benefit was the priority. Respect of each team member and their effort was something that the Hot Dogs acquired in time. It was a challenging task to compile the final product and to turn it into a comprehensive report. Each member s skill set was put to their optimum use. Tasks were divided amongst the members. There were a few issues that had to be tackled in the way : Lack of precise knowledge on the product and the Mekong Delta. Efficient use of materials as high maintenance materials was not affordable. Communication gap amongst members when meetings were missed. While in contrast the positive effects of the EWB challenge on the team were: Friendships and team bonding enhanced over the time.

14 Page14 Knowledge on a different part of the world that is the Mekong Delta was gained. Learned the effective use of materials and how minor changes to these materials could change the way of living. The understanding of real issues in the world that EWB challenge has provided will be very helpful to every participant. It will not only effect its education positively but will also prepare each member mentally to face and tackle the problems in their near engineering future. By Zheng Xiangnan The engineers without borders design challenge gives students an opportunity to work with others like a real engineer. From cooperation with team members, I have leaned many group skills. My listening ability also get improved, now, I can understand what does others actually meant, and what people really want to express. Though the project, we encourage each other and try to maintain a harmonious atmosphere. We solve problems and dispute as a team. We divide task reasonably, and share responsibilities. This project is a good chance to apply class learning to the real world to solve real world problems. And, I also learned linguistic and social skills which I l lacks. The engineers without borders design challenge helps student know other nations, their cultures and their life. It is an excellent experience. Student can make a contribution to the people in this public and meaningful way, people can

15 Page15 really do something for this world and feel like they have become a part of world. It helps people understand how happy we are. And cherish our life now. By Mukund Ragunathan I have learnt enormously about what it takes to be a part of a competently functional team. From the experience I have had so far, I have recognized that a lot of fundamental team processes have to be efficiently applied to enable a functional collaborative group. A major lesson I have learnt about team processes is that a lot of the time for the process to work, it requires the participation of all the team members, not a few. One example of this would be attendance. If only a few people attended the meetings, the team would be highly dysfunctional, hence resulting in a low quality product at the end. Another major lesson I have learnt about team processes is that interpersonal skills are crucial to the success of a team. Interpersonal skills include diplomacy, maturity, and tact. Because from this group project experience so far I have learnt that successful collaborative efforts are driven by healthy relationships between team members. Ill will does nothing good for anyone. As a strength, I consider myself to be quite articulate. It is my belief that I can use this further to my advantage by using this skill to help write the final report for the team. The use of a high standard of English would mean a higher grade. Another strength I believe I have are my presentation skills, I volunteered

16 Page16 to take up a leading role in our class presentations, and am satisfied with my performances. My team mates in their feedback praised my poise and confidence during both occasions. As a weakness, I would say my decision making isn t as team orientated as it can be. There were several occasions I would realize that my idea s were too grandiose and unrealistic for the Mekong region, especially considering the budget constraints. Another weakness I recognized in myself was that I should have payed more attention to the ideas of other teammates, as they may misconstrue it as rudeness. I am developing my listening, interpersonal relationships, and analytical skills. I believe that with focus, I should be able to improve and incorporate these team processes into my collaborative and communication capabilities to become a better performing component of a competent and efficient team.

17 Page Problem scope Water is a very essential element for everyone, people in the Mekong delta consume on average 2 liters of water each day. Drinking water in the Anh Minh district is collected from three sources, which are rainwater, bore, and surface water. In Mekong delta area, 85% of rural people have access to bore extract underground water.(ewb 2012) The bore water is not turbid, but underground water usually contains various metals which is harmful for human consumption, such as arsenic, fluoride and nitrates. Hard water is bore water which contains a high mineral content. Hard water is not hazardous to human body and health, but it may cause costly maintenance and breakdowns in boilers and other equipment that comes in contact with hard water.(wikipedia 2012) Surface water in the area is sourced from Mekong River. People in the rural districts do

18 Page18 not have access to toilets, so human waste is disposed into the rivers. This results in the river becoming extremely dirty; it contains high levels of E-coli, bacteria. These micro-organisms will cause various different types of infections and diseases for the people in Mekong Delta area. Rain water plays a fundamental role for the water supply in the world, especially in the tropics, like Mekong delta area. However, it is not considered directly potable, the collected water usually contains soil, bacteria, insects, and other pollutants. The quality of rainwater also is dependent on the air quality in that area. So, they require an affordable water treatment solution to remove the contaminants, such as bacteria, protozoa, heavy metals, chemicals and salt for human consumption. 1.2 Technical Review Clean water is essential to any form of human inhabitance. The problem being addressed is water sanitation in the Mekong delta. The Mekong delta in Vietnam is a major rice growing area, per year this region alone produces more rice than Japan and Korea combined. The Mekong Delta has an estimated population of 20 million; this is more than 20% of Vietnam s population. Around 85%, which is 17 million residents of the Mekong population live rurally. Much of the population in the Mekong delta subsist on less than $1 US per day, therefore

19 Page19 domestic and commercial water filtering infrastructure is inaccessible to the majority of the population. The lack of clean water consequently results in various public health issues such Hepatitis A, typhoid fever and cholera, to just name a few. There were many different methods to solve the issue that were considered, such as large scale treatment of water through a chemical medium, and creating a privatised and commercialised water filtering infrastructure. These methods are too costly, unrealistic and incompatible with the economy of the Mekong delta. Using a water filter to treat contaminated water proved to be the most appropriate solution to this issue, but many consumer oriented water filters which were investigated were not fully suited to the requirements of the Mekong delta community, areas considered important were filtrate competency, cost, sustainability and operational lifetime. Therefore the main focus through team collaboration was to create a water filtering solution which met these parameters, and to enrich and change for better the lives of the residents in the Mekong delta. Water sanitation is a major public health issue in the Mekong delta. The current water collection and distilling infrastructure is very crude and inadequate. For water collection, the most popular methods are rainwater collection jars, utilizing surface water and bore wells. Rainwater is collected from the roof and directed via a gutter system into large, 1m^3, cement jars for

20 Page20 storage. The jars are open and so it is easy for water to become contaminated, impurity build up is a common problem. Open water jars can also become a breeding ground for mosquitoes. There are no first flush systems in the area. Rainwater is typically consumed with no treatment. Surface water is collected from rivers and ponds for drinking and cooking. The water is typically dirty and contaminated and is highly saline. 85% of rural households have access to a borehole well with a hand pump to draw the water. Well water often contains heavy metals including naturally occurring arsenic and is often highly saline making the water undrinkable. Typically the wells are 100+m deep. Habitat for Humanity estimates that in some areas the wells would need to be 250m deep for clean water to be collected5. As of now there is no widely used water filtering method used in the region. This issue should be corrected as quickly as possible, in order to help improve the health and lifestyle of the Mekong population, who as Vietnam s rice producers are vital to its domestic economy and the international rice market.

21 Page Design Requirements: In designing solutions for the issues outlined in the design brief, there are five design requirements that have been considered as high priority during the design process. Proposed ideas and options are to be evaluated in relation to each other, according to the following set of requirements: Cost effectiveness Cost effectiveness is an important consideration in the design solution; the final proposal must provide maximum benefits at a reasonable cost for the end user, in other words good value for money. Many people of the An minh district are of poor households and earn low wages, therefore the affordability is a major implementing factor. The total cost of the proposal must take into account the following: Materials Implementation and transport Construction Maintenance and ongoing costs

22 Page Effectiveness of solution Clean drinking water is a major environmental determinant of health, Every year there are 2 million diarrhoeal deaths related to unsafe water, sanitation, and hygiene the vast majority among children under 5. The design solution must be effective in treating the local water supply to acceptable world drinking water standards. The water quality test results show that there are two types of bacteria within the bore water supply which are E-coli and Coliform. Additional problems are high nitrate and nitrite levels and foul odor. The design solution must effectively remove the specified problems and bacteria from the local water supply Cultural and social acceptance The proposed design must not conflict with the values and beliefs of the community; otherwise it can result in the failure of implementation and long term use of the idea. The proposal should consider the local cultural and social practices, and should fall within the ethics of the community; every part of the proposed solution must be accepted by the community to succeed. The proposed solution should be low impact in terms of affecting and inconveniencing the community s day to day life.

23 Page Effects on environment The design should source and utilize materials which pose a low or minimal environmental impact on the region. Some factors to be taken under consideration is the source of materials, the materials considered should be locally sourced in order to minimise its carbon footprint. Also the waste products produced from its production, long term effects and the disposal of the system after its lifespan need to be considered Sustainability The proposed solution must be sustainable and easy to maintain for the community to continue using it. Sustainability is an important factor in the development of the project and should not be overlooked. The solution must be simple and easy to understand, if the proposal was too complex, there is a risk that the community will not use it. Also the lifespan of the design and the availability of materials should be considered. Maintenance should be infrequent and inexpensive, labour intensive and costly maintenance puts the solution at risk of being abandoned and the community reverting back to their previous methods of ineffective water sanitation.

24 Page Design options 2.1 Ultra Violet ( U.V.) The Ultraviolet or the UV system of filtration is based on the concept of disinfection by letting the flow of water pass through a source of Ultraviolet light. This might be a UV light bulb or the elements from the natural rays of the sun. The inactivation of the detrimental microorganisms is done by the waves of ultraviolet light that the light source emits. Inactivation prevents the virus, mould, parasites and bacteria from reproducing. This process modifies the deoxyribonucleic acids (DNA) of the living organism which alters their reproduction system. ( Canadian Mortgage and Housing Corporation, 2008)

25 Page25 UV disinfection is best for treatment of living organisms. Its efficiency may change in presence of physical contaminants i.e the contaminants that are visible. The impurities may block the rays of Ultraviolet light and this may lead to the survival of the harmful particles. Therefore, it is often used as a post filtration system. This ensures that the water is safe and potable. There are two UV filtration systems considered which are UV bulbs and the natural solar disinfection. Ultraviolet Bulb systems in the household application can be used by attaching a small portable system to a faucet or it could also be mounted under the sink. This system would require a protected UV bulb, water chamber, power supply. This cost anything between $300-$1200. The Natural Solar Disinfection system is not so complicated but the process is extremely slow. This disinfection is done by storing filtered water into empty transparent plastic containers such as bottles. These bottles are then left in the open exposed to the sunlight. The UV light present in the sun rays then treats the water, inactivating the dangerous microorganisms. This process can take few hours on a regular day or over a day if cloudy.

26 Page Reverse Osmosis Reverse Osmosis is one of the most sophisticated methods of water purification available at the time being. Reverse osmosis is generally utilized for improvement of water used for drinking and cooking in general household conditions. It eliminates most of the natural impurities which are physically present, along with any inorganic chemical components, bacteria, salts, heavy metals and other impurities present in the water. It dramatically enhances the appearance and odor along with the taste of the water purified. (Reverse Osmosis) (ESP Water Products) The reverse Osmosis purification is done by a booster pump and a semipermeable membrane. This super fine, semi permeable membrane has pores. These measure about microns in diameter. An average pressure of psi is used to pump the water through the membrane. This ensures that all the impurities that is larger than one thousandth of a micron is blocked and removed. Its pre- filtration process usually involves a sedimentation filter to remove silt,

27 Page27 sediment, sand and clay from the untreated water. This makes sure that the large contaminants do not block the pores of the membrane and the water flows smoothly. (Vertex Hydropore: Reverse Osmosis Definition) The solution for heavy metals and minerals like chlorine, that may harm and deteriorate the membrane, is an additional carbon filter. Activated charcoal enhances the filters capacity to improve taste, smell and the extra chemicals. Reverse osmosis filters come in various range, depending on sizes, portability etc. therefore the prices range from $400 - $2500. Along with that there is an annual component maintenance cost of about $ Activated Carbon Filter The process of activated Carbon or activated charcoal filter is preferred due to its high efficiency of absorbing of impurities. Activated carbon is quite different from regular carbon. It undergoes a process to gain positive charge; in short it is altered to lose electrons. With this process its attractive quality soars and the chemical impurities get filtered. The filter requires maximized surface area to volume ratio just to increase the rate of absorption due to its highly porous quality. Activated Carbon system is a very popular filter layer commonly used in regular household water purification systems. Its key features include ability to enhance taste, reduction of odour and it is highly efficient in removal of organic compounds such as VOC s, radon and chlorine. This is popular pre-filter used in other water filtration systems such as Ultraviolet and Reverse Osmosis filters. (Home water purifiers and filters, 2008)

28 Page28 Coconut shells, wood, coal etc are the most popular source of carbon. These are readily available in every region of the earth. Although these are sources of regular carbon, the process of its activation is simple. All that s required is a baking area or an industrial oven if feasible for proper Activated carbon activation. Pits dug in the ground are also used as the activation units along with storage drums. The lack of oxygen and high heat are the essentials for charging the carbon and converting it to activated carbon. (Activated Charcoal) Carbon blocks have higher contaminant removal ratio, even though in regular household or small unit filtration systems prefer granulated carbon filter due to its maximized surface area to volume ratio as mentioned above. These filter layer of activated charcoal have quite long lifetime but after its expiry it should not be reused and should be replaced instead. An average carbon filter costs about $5-$7.

29 Page Ceramics The most popular method of water filtration in the third world countries or under developed and developing nations are Ceramic Filters. Ceramic works on the principle of trapping contaminants within micron sized pores like Reverse Osmosis, the pores of the ceramic are the size of the water molecules. Hence it allows only the molecules of water pass through it and block every other physical impurity. This filter when treated with colloidal silver prevents bacteria and growth of other micro organisms like algae and mold. In today s industrial world two types of ceramic filters are available. One is Candle shaped and other is pot type filter. The candle shaped is the most used and commercially manufactured type of ceramic filter. This is the most economical option for people in villages specially the ones in the third world country as in Vietnam s Mekong Delta. Candle filters are sometimes filled with activated charcoal, which improves the purification method of the filter and makes it more efficient. Ceramics are generally classified on the rating of their flow rate. This depends on various factors such as surface area, the porous nature of the material and the length on the ceramic filter. (Delta Alliance) The pot shaped ceramic filter is more native version of the commercially used Candle ceramic filter mentioned above. This in term is very basic in nature,

30 Page30 which is generally produced by baking clay pots. The pots have micro pores in them which allow only water molecules to pass through, which prevents the impurities to passing through. To enhance the purification of this pot filter it is sometimes baked with special herbal tea leaves or coconut shells which later combusts and forms into a layer of activated charcoal. This drastically improves its purification system as the water is now also treated for odour, taste and heavy metal impurities. 2.5 Slow sand filter Slow sand filter, also known as biosand filter, normally is 1 to 2 meters deep. Typically, the slow sand filter is divided into 5 zones. (Slow Sand Filter) The top of filter is inlet reservoir zone, the main function of this zone provides an inlet for people to pour the water into system. The standing water zone is beneath the inlet reservoir zone, water at this zone is turbid and muddy, this zone allows oxygen to reach the sand filter and keep the sand under water. The biological zone is beneath the standing water zone, it occupies up to 5 to 10 cm above the sand layer. (CAWST 2009)Various micro-organisms live in this zone, which is the top of few millimeters named hypogeal layer or

31 Page31 schmutzdecke (Wikipedia 2012). The Schmutzdecke is formed in the first days of operation. It consists of a gelatinous biofilm matrix of bacteria, fungi, protozoa, and some aquatic insect larvae. When the water passes through the schmutzdecke, bacteria, protozoa, and fungi will absorb the dissolved organic material. (Slow Sand Filtration for Water Treatment) The Non-biological zone is under the biological zone. Living microorganisms cannot occupy this area, because there is no nutrients and oxygen. The Gravel zone is at the bottom of slow sand filtration system. Gravel zone consist of separating gravel layer and drainage gravel layer. The separating gravel layer is formed using small sized gravel and will only allow water pass through it. The layer holds the sand in place and stops the sand pass into the drainage gravel layer and outlet tube. Larger gravel constitutes the drainage gravel layer, the function of this layer is supports the separating gravel layer. This zone plays a role as important as bio-sand zone. Without the gravel zone, the sand will clog the outlet tube, which results in highly restricted water flow. During operation, water will flow through the filter downwards due to gravity. When the water passes through the bio-layer, the foreign bodies are trapped by a mucilaginous matrix, and absorbed and metabolized by the microorganism. All contaminants are contained in the

32 Page32 bio-layer. When the water reaches to the non-biological zone, the water is drinkable. Micro-organisms would not survive due to the lack of nutrients and oxygen deficiency. People do not need to worry about microbial residues. Finally, water passes though the gravel zone, and flows through the outlet. The efficiency of slow sand filter is dependent on the particle size distribution of the sand and cross section of filter. Slow sand filter include many advantages. Firstly, no energy cost. That means the filter can operate and does not rely on the supply of electric, petrol, and natural gas. Therefore, slow sand filters are suitable for the areas that lack reliable energy supply. Secondly, these types of filtration system are easily constructed by people with low skills. The procedure is simple and it can be installed by the people who have never installed slow sand filter before. Thirdly, the systems require very little maintenance, people just replace and clean the top 2 to 3 cm of sand, every 4 to 6 months. Finally, the cost for installation and maintenance are much lower than other filtration systems. According to Wiley s research in 2006, building a 1-acre filter which could supply people, at a cost of $60000, which is an initial cost, is $3 per person. If the maintenance is considered, the actual cost of the slow sand filtration system could be as low as 36 cents per person annually.

33 Page Solar Distiller Water treatment using solar distillation work using s olar heat and a difference of temperature. The distillers usually consist of a roof made of a sheet of glass or clear plastic, and water collector. The sun s rays travels through the transparent sheet and causes the contaminated water to start evaporating. The water in gas form separates from the contaminated water and rises up and to condense on the cool surface of the roof. The gas changes in liquid form because of the difference of temperature between water gas and the roof. Eventually, the water travels down along the slanting roof and goes into the water collector. This process creates water of the highest purity but the downside to this solution is that it does not work at night time and it takes a long time to treat a large amount of water. (Solar Still a perfect Water Distiller) The cost of materials to build a solar distiller is not high because the filter could be made using recycled materials such as pet bottles or a plastic bag, but the quality of it is not as good compared to a as factory manufactured distiller. This point is an advantage that they are appropriate for the situations in underdeveloped nations.

34 Page Water storage solution: Ferro cement tanks for additional water storage. As part of the water treatment system, water storage before the treatment is important. Currently rainwater collected in the clay jars do not last through the dry season because families do not have enough storage. Ferro cement water tanks are a cost effective solution, which can be built easily with little skilled labour. Water can be stored in a hygienic condition which is a primary requirement for water harvesting. The basic construction of Ferro cement tanks consist of steel or iron mesh for reinforcement and cement as the raw material, a requirement for storing drinking water is that the tank is covered to avoid contamination. The tanks can be made on site or at a factory, then transported to the site. Compared to reinforced concrete tanks, ferro cement are lighter in weight due to the thin wall thickness and withstand shock better as ferro cement is more flexible. The material cost to construct a 600 litre ferro cement tank is estimated around $14us, which comprises of 37 kg cement, 110 kg sand, 2 kg of steel rods, 2 kg of wire mesh and a tap. This is cheaper per litre of storage than the 200 L clay jar commonly used. Fittings are built into the tank during construction and may include a drain for maintenance, one or more taps for water collection, an inlet pipe and overflow pipe with screens to prevent entry of insects.

35 Page35 Rain water collected from existing roof tops are channelled through a screen into the tank, the screen helps keep contaminants from entering the tank. Environmentally, ferro cement tanks compared to PVC tanks are very ecofriendly. 2.8 Option Selection Filter Type Advantages Disadvantages U.V Bottles/U.V Bulbs Inactivates bacteria Expensive Only inactivates bacteria so should not be used alone Requires power Solar Still Produces pure water Dependent on sunlight Produces low volume of water Activate d Carbon Cheap to make Materials readily available Doesn t remove bacteria Not very good at removing heavy metals

36 Page36 Slow Sand Cheap and easy to make Easily obtained materials Doesn t require power to operate Heavy and large Slow flow rate Ceramic Cheap and easy to make Simple Has high maintenance as it needs to be cleaned periodically construction Reverse Osmosis Filters out more contaminants than all other filters Very expensive Advanced technology Needs pressure to operate The advantages and disadvantages of each filtration system are set out on a table for an easy way to compare them to each other. The table below compares each filtration system s ability to filter out different contaminants.

37 Page37 Filter Sediment Heavy Bad Bacteria Type Metals Tastes and and Viruses Odours U.V Bottles/U.V Bulbs Solar Still Activated Carbon Slow Sand Ceramic Reverse Osmosis Effectively =Removes Effectively =Partly Removes =Doesn t Remove The three main sources of water collection in the An Minh district are rain water, bore water and surface water. Each type of water has its own problems,, rain water becomes contaminated by insects going into the storage pots which breeds bacteria and viruses; bore water is contaminated by heavy metals and some bacteria; Surface Water which is collected from rivers and ponds are used

38 Page38 as waste disposals so it is highly contaminated with bacteria, viruses and has a high level of sediment. When comparing these water sources and the way they were contaminated, it was decided that the solution would have highest priority in the removal of bacteria and viruses. The following priorities are heavy metals, bad tastes, odours and sediment to make the water fit for human consumption. Looking at the two tables reverse osmosis is the most effective at removing all the contaminants but its cost and technology beyond the regions capability, so it isn t a good choice for the people in this area. The solar distiller system is very good at producing clean water but it is dependent on sunlight and since this area has a wet season it would be ineffective for half the year and the rate of water it produces is very low. Both of the U.V systems only inactivate bacteria and do not remove the physical contaminants left behind, so another filtration system would have to be used in conjunction. The U.V bulb system is expensive and requires power to treat water. Which are two factors that are unwanted or best kept at a minimum. Slow sand is very good at removing most of the major contaminants, the only disadvantage about these systems is that they are large, heavy and have a slow flow rate. Activated Carbon is cheap to make and is good at removing bad tastes and odours but does not remove bacteria and viruses. The Ceramic system is cheap and easy to construct and can remove sediment, bacteria and viruses but ceramic filters are very fragile and need to be cleaned very regularly.

39 Page39 After considering all this information and comparing the systems with price, reliability and local impact. It was decided that a combination of slow sand and activated carbon should remove almost all contaminants and are both very cheap and easy to construct and maintain. 3.1 Summary of Design The proposed solution to the water problem is a hybrid water filter design combining a Slow Sand system with Activated Charcoal. The water is poured into the top of the slow sand filter which makes contact with a diffuser which allows the water to enter the inside of the filter at a slower pace to stop any damage occurring to the sand layers, the water is filtered as it flows through the sand, almost all contaminants and sediment are trapped within the first layer of sand. The water then flows out the filter through the outlet positioned at the lower side of the drum. Finally the water passes through the activated charcoal where trace contaminants are removed and taste and odour are improved. The treated water is collected and stored in a sealed container ready for consuming.

40 Page Detailed Description Functional Diagram

41 Page Functional Description Slow sand filtration is a technique used to filter water at very slow rates where the typical filtration rate of 0.05 to 0.10 gpm/ft2 is at a minimum fifty times slower than rapid rate filtration. The technique has been used for portable water filtration for hundreds of years. Due to its slow rate, it requires a large area of land for filtration basins. It is well suited for areas with small rural communities as they have plenty of available land and this process does not require a high degree of operator skill or attention. Bio Layer The process of sand filtration is a simple process as it does not involve any chemical addition and particle removal is accomplished through biological procedures. The biological processes take place in the top surface of the filter which is also known as the schmutzdecke. It is however believed that the processes throughout the depth of the filter affect particle removal. There is a 'ripening' period which lasts from several weeks to several months, which is necessary for the organisms to mature in a new slow sand filter. As in the case of rapid rate filters, sand filters are not backwashed but are scraped or harrowed periodically. Average time after which they are harrowed/scraped range from 1-12 months depending on the quality of water. During scraping the top 1/8-1/2 inch of sand is removed from the filter bed and replaced to restore the sand of the filter. In some cases the filters are harrowed

42 Page42 to break the top layer and reduce head loss through the filter. In this case sand is not removed but the top layer of organic material is broken up and floated off the surface using flow up through and across the surface. After the filter is scraped or harrowed the filtered water is typically sent to waste for a period of 1-7 days to allow the organisms to re-establish. Pause Period The biosand filter is most effective and efficient when operated intermittently and consistently. The pause period should be a minimum of 1 hour after the water has stopped flowing up to a maximum of 48 hours. The pause period is important because it allows time for the microorganisms in the biolayer to consume the pathogens in the water. As the pathogens are consumed, the flow rate through the filter may be restored. If the pause period is extended for too long, the microorganisms will eventually

43 Page43 consume all of the nutrients and pathogens and then eventually die off. This will reduce the removal efficiency of the filter when it is used again. Standing Water Layer Correct installation and operation of the biosand filter requires a standing water depth of approximately 5 cm (2 ) above the sand during the pause period. The standing water depth can be 4-6 cm, but ideally it should be at 5 cm (2 ). A water depth of greater than 5 cm (2 ) results in lower oxygen diffusion and consequently a thinner biolayer. A high water level can be caused by a blocked outlet tube, an insufficient amount of sand installed in the filter or the sand settling in the first few weeks of use. A water depth less than 5 cm (2 ) may evaporate quickly in hot climates and cause the biolayer to dry out. A low water level may be caused by too much sand being put into the filter during installation. Flowing Stage After the filtration from the previous stages the fine sand layer blocks the smaller particles of impurities in the water remaining. Later it is passed through the different allotted layer of the coarse sand and small gravel and the larger gravel. This is just to ensure fine quality of purification of water. This refines the system s filtration system and enhances the quality of the out flowing water.

44 Page44 Activated Carbon Activated carbon filter layer is added to remove harsh chemical impurities such as heavy metals, nitrates, arsenic etc. The charged particles of carbon treat these. As a result the water becomes odourless, improved taste and safe to drink Manufacturing procedure Materials: Plastic drum, plastic drum lid with deep lip, sand (fine and coarse), gravel, cloth, rubber o rings (19mm), 20 mm pipe Wash the sand People should clean the filtration sand before using them. The steps required to wash the filtration sand are listed below. Put small amount of sand into bucket, about 10 centimetres deep. Pour clean water into the bucket. The depth of water is approximately 30 cm. Stir the sand energetically; make the entire sand move in the bucket. Pour the dirty water out, Repeat the above steps until the water in the bucket is roughly clean.

45 Page45 Put the washed sand into another bucket. Treat the rest of sand and gravel by the method above. Place the sand and gravel on a cover or concrete surface in the sun to dry. Construct the filter (Solid Works, 2012) The filter will look like this when finished

46 Page46 Manufacturing procedure Clean the container with brush and disinfectant. Rub the in wall with coarse sand paper. Drill a hole at 8 cm above the bottom. The diameter of the hole must be sized to match the pipe. Drill small holes in the first 35 centimetres of the end. Seal the end (the end with holes) of the tube. Install the outlet pipe. Make sure the end with holes is inside the drum. Use waterproof tape at the junction to avoid leaking.

47 Page47 Connect the pipe and carbon filter as show in the picture below

48 Page48 Put the big gravel layer on the bottom, approximately 10 centimetres deep. Make sure the gravel layer is able to cover the outlet pipe. Next, put the little gravel (10 cm deep), coarse sand(30cm deep), and silver sand(350cm deep), sequently. Drill many small holes at the top of the lid. Cover the container with lid. Put the cloth on the lid.

49 Page49 Manufacturing Ferrocement tanks: To construct a ferro cement tank, firstly a suitable site must be chosen if the tank is to be built on site. The foundation must be prepared, by levelling the site and excavating 100mm of the topsoil. Drive a wooden post into the centre of the site, and make a circle of radius 600mm using a string. This circle will become the footprint of the tank. The base slab of the tank is laid first by covering the base with 15mm of concrete, mix the mortar in a large container; the mix will require one measure of cement, three measure of sand and three quarter measure of water. Materials needed to construct a base are 13kg of cement, 36kg of sand and 16 litres of clean water. Arrange two sheets of steel mesh diagonally on top of the concrete; five steel supports are attached to the slab reinforcing wire at equal intervals. A second layer of concrete 10mm is laid to cover the steel mesh. While the mortar is curing, it must be kept damp for several days to prevent

50 Page50 cracks. Old rags, sacks or matting can be used to help keep the surface damp. 10kg of cement and 28kg of sand and water is to be mixed for the walls. Steel mesh is wrapped around the five steel supports to become the reinforcement of the walls; the mesh is tied to the support with fine wire. A pipe is inserted into the mesh 100 mm above the base for the tap and another pipe is placed at the floor of the base for maintenance purposes. At the top of the walls, two pipes should be inserted, one for water inlet and another for water overflow. The plastering of walls with mortar will require two people, one on the inside and another on the outside. This will prevent mortar from falling through the mesh; the plastered mortar will need to be kept damp to prevent cracking. The roof of the tank can be constructed on even ground on top of a sheet of plastic; the outline is made by a circle of radius 620mm, similar to creating the base. The remaining cement and sand is mixed, lay down 15mm to the plastic circle then place the steel mesh on the concrete and lay down another 10mm to cover the mesh. At the circumference of the slab, create a raised lip using the mortar with a trowel, the lip will help prevent contaminants from entering the tank.

51 Page51 The roof can be positioned after a few days of curing. The tank will need to be kept damp for two weeks before filling of water; this will help prevent cracking and is important for proper gaining of strength. The inlet and outlet pipes at the top of tank must be screened to prevent insects and large particles entering. 4.0 Implementation Plan Implementation Overview Even the best laid plans are useless without the proper nurturing during their inception. Putting the process into effect will be one of the most crucial parts of the whole project. Because if solution is not implemented in the way it is conceived to be, then there is a very real chance of its effectiveness being compromised. Communication and establishing a relationship with the target market. Because this is a humanitarian effort, there has to be established a positive and healthy relationship with various members and agencies of the intended community including the regional council/municipalities and the government. As the area of focus is the Ah Minh area of the Mekong delta, there must be a focus on establishing a positive line of communication within their community. The team has to look to ingratiate ourselves and make known the goal of helping the community. The group s personal mission is to not just help the Ah Minh community, but to empower them so they can help themselves in

52 Page52 the future, so that the power to an enriched existence can be within the realm of possibilities, that is the ultimate goal, with the first step being water sanitation. If successful in communicating this vision to the locals and the powers at be, they will be met with enthusiasm and friendship. Logistics The team being based in New Zealand; requires the need to establish a headquarters for the operation. The headquarters must be reasonably cheap to rent since the project would have to fund it extramurally. Ideally the site would be a part of a municipal building like a post office or a police station; this will then lend an air of professionalism and trust in the eyes of the locals. Also, it would also serve as a lasting base for maintenance for the filters and parts supply after the project has been established. For smooth operation, it is required to have a number of staff to help with the operation. This would be mandatory as the team would need an English speaking local to serve as a communication liaison between them and the locals. Therefore in order for all of this to happen the team will obviously need to fundraise to effectively start the project. Educating the locals As they are attempting to solve a problem using a consumer product, they will have to educate the locals about the filter in order for them to fully appreciate its usefulness and its importance in bettering their daily lives. Therefore they will have to host public tutorials, to do this. The tutorials will have to be simple enough for the layman, but effective enough to fulfill its purpose. Tutorials are to

53 Page53 be undertaken by reasonably educated and English speaking locals, so that their understanding and appreciation of the product can then be translated over to the locals, who are after all going to be the beneficiaries. Fund Raising This would have to be the first goal on the agenda, and would need careful consideration before the operation gets underway. An appropriate modus operandi is needed in order to this. Methods like sausage sizzles or cake stalls would not do as they are too informal and happy for a serious and concerning cause such as water sanitation. Methods such as a short online video explaining our cause and an option for internet donations would be one such way. Corporate sponsorships in exchange for brand placement would be another plausible option, because this is a humanitarian effort this would no doubt generate good publicity for companies who participate. Also a consideration would be approaching select well to do individuals who have a prior reputation of philanthropic achievement, and requesting financial support Component list Plastic Drum PVC pipes Sand (Various size) Small & Large Gravel Activated Charcoal Tap Ferro Cement tank & Cloth

54 Page Implementation Procedure STEP 1: FUND RAISING Fundraising is a pivotal aspect of the whole operation, and must be attended to first off all after all the planning for the project has been undertaken. It is expected that the implementation process to be quite expensive, and in order for the implementation to be successful, money has to be spent. They are aware that even though this is a nonprofit humanitarian effort, they cannot expect financial help from the Vietnamese government. Therefore the team must look to raise capital ourselves. Major channels of sponsors they are targeting are corporate brands. The aim is to offer brand placement in exchange for sponsorship and any other kind of help. They can also use the internet to raise awareness to our cause by producing a short video explaining our operation and adding an online donation method. If the video becomes viral, this may potentially raise a lot of money for their cause, as well as raise awareness. STEP 2: Manufacturing Filters Once the implementation capital has been acquired, they must focus on mass manufacturing the filters and related accessories in the most economical way. They will look to find a supplier in Vietnam itself and preferably within the Mekong region, in order to save on export costs. Also this has the added benefit of bringing revenue into the local Mekong economy. Locating a local supplier in the Mekong region, they might be inclined to awarding a discount in recognition of the noble nature of our endeavour.

55 Page55 STEP 3: Establishing Headquarters The team would need our own premises to operate out of. The base would initially act as an administrative centre, warehouse for the filters and accessories, possibly even lodgings for personnel. The lease would obviously come out of the team s expense. They are hoping to lease into buildings such as disused municipal buildings, where the lease could be cheap or even free through the largesse of the local council or government authority. STEP 4: Recruitment An operation of this scale obviously needs a certain number of staff in order for efficient functioning. They are hoping to attract English speaking volunteers, who can communicate effectively with the locals. Depending upon the capital they are able to fundraise, they would like to employ a reasonably large staff, they believe this can then streamline the implementation process and get the product to the people as soon as possible. STEP 5: Distribution of Filters This is a vital part of the operation. They would like to first educate the locals, and only after that sell the filters, for a nominal fee. This way, they believe that this will extend the lifeline of the filters as the locals will then be educated in how to operate the filters, and appreciate their value of the filters function. They would like to compile a database of all the families we sell filters so we can compile data for future reference, when they look to optimize on the process. No doubt, the information would come in useful other activities. In accordance with

56 Page56 the customers privacy rights, they shall of course inform them of the information collected and obtain prior permission with all parties. STEP 6: Ongoing Maintenance After the previous steps of our implementation process has been completed, we would like to leave a small, but permanent maintenance centre, with two full time staff. The purpose of this centre would be to sell new filters, components of the filters, accessories, and also to repair filters and other such related activities. They believe that this permanent presence will serve to burnish the longevity and the relevance of the water filter as a viable water sanitation method in the region. The wages of the two employees will come out of the proceeds of the maintenance shop Additional Uses A consumer product with such a wide ranging functionality such as the proposed design can be used for a variety of situations, both in the consumer and professional markets. In an economically strained demographic such as the Mekong District, the target market will no doubt find innovative new ways of increasing the product s utility into other areas, most of which even we as the designers would have never dreamed off. As the saying goes; necessity is the mother of invention. If used on a sufficient scale, the water filters can be used to irrigate certain areas of premium agriculture. A two week long experiment was conducted, in

57 Page57 which seeds were watered with water processed by filter, tap water and salt water. The seeds that received filtered water grew the best, while those watered with tap water had fewer leaves and did not grow to as great a height. The seeds receiving salt water did not sprout. Therefore this provided a conclusive input that filtered water certainly has potential for food growth. It is an amazing utility for small vegetable gardens where Mekong residents can grow their own produce, to supplement their groceries and save enormous sums of money. 4.3 Discussion Strengths and weaknesses of the design. The purpose of the project is to aid communities that are in need of assistance due to current problems, the Hotdogs decided to focus on improving the drinking water supply to the Anh Minh district, the result should be meaningful and sustainable. The first option considered was a household slow sand and activated charcoal filter system, that would treat rain and bore water for human consumption. The second option considered was a small communal sized slow sand system that would treat mainly bore water for human consumption. Cost: The greatest challenge was focussing on keeping the cost as low as possible by using locally available materials, it was estimated that the average wage in the area was around $3us. the cost of the project was often compared to

58 Page58 how many days worth of wages, to give us better insight into the relative costs. While cost effectiveness was high on the design requirements, the cheapest option was often not necessarily taken if it was ineffective; had substantial negative effects on the environment or clashed with the cultural and social traditions. Ongoing costs are very low as the solution does not require a supply of electricity, gas or chemicals to treat the water. The only ongoing costs is the cleaning of the top layer of the sand which is required every few months and the replacement of the filter medium every few years. Initial costs for the household slow sand activated charcoal filter were moderate, while the community filter and ferro tanks were relatively high but still attainable. Culture and social traditions: The implementation of both options does not conflict significantly with the local values, culture or social traditions. The options do not change their water source, thereby reducing the possibility of negative effects with the community and will only contribute to better health of the community by providing a system that would eliminate water borne diseases. Low maintenance will help the system become socially adopted and improve the chances of continued use.

59 Page59 Efficiency of solution: Slow sand filters are almost 100% efficient in removal of particulate matter, parasites and larger organisms. Up to 90% to 99% reduction in bacteria, viruses, iron, and arsenic. Due to high efficiency in removal of contaminants, high quality potable water can be produced. Water which has high turbidity poses a problem for slow sand filters, high turbidity can quickly clog the flow of the filter, resulting in short periods between cleaning. Water used in the slow sand filter must be from collected rain water or bore water, surface water can affect the maintenance period if it is turbid. Water production is reliable, consistent and continuous, filtration is continuous as long as pre-filtered water is being replaced as it runs through the filter. The solution gains reliability from the lack of sophisticated moving parts and dependency on a external energy supply. Materials: As the materials are sourced locally and the construction is taken on site in the community, economically the project will provide additional work for the local industry, people will develop skills and knowledge which aids any repairs and maintenance that would be required later on. All materials considered are environmentally friendly, with one exception being the plastic drum used for the body for the household design. Though the plastic drum was not biodegradable, the long lifespan and reliability meant it

60 Page60 posed a relatively low environmental impact so the benefits outweighed the negative factor. Technology level: An advantage of low level technology is a simple design that can be easily understood by the community. There are no sophisticated machines which will require specialised maintenance and the treatment of water is not dependent on an external source such as electricity or fuel. Ferro tanks: The issue of rain water storage running out during the dry season was addressed by implementation of ferro cement water tanks. The solution provided many strengths, for example, storage was cheaper per litre than the clay pots, low maintenance requirements and ease of repairs; it did not conflict with traditions as it only provided additional storage but did not change the source.