Household Water Treatment for Arsenic Removal Fact Sheet: Adsorption Magc-Alcan Filter Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Arsenic  Turbidity  Taste, odour, colour What Is a Magc-Alcan Filter? The Magc-Alcan is a two bucket filter. The buckets are in series and both filled with an American-made activated alumina media. The media has been developed by MAGC Technologies and Alcanof US; and it is produced by thermal dehydration (at 250- 1150˚C) of an aluminium hydroxide. How Does It Remove Arsenic? The Magc-Alcan filter removes arsenic by adsorption (adhesion or sticking together) of the arsenic to the enhanced activated alumina which is porous and has a high surface area. Removal rates can be sensitive to varying pH levels, so additional equipment may be required to control pH levels. Operation Magc-Alcan Filter Nirmal Filter  Place two buckets (with taps) filled with (Photo Credit: Ngai) activated alumina media in series using a stand  Place a safe water container after the second Key Information tap  Pour water in the top bucket with all of the taps Treatment Production Cost Lifespan open Efficiency Magc-Alcan: Similar Tchnology: Nirmal Filter 80-85% arsenic $35-50 100 6 months to 1 A similar filter called “Nirmal Filter” also exists in removal capital cost litres/hour year India. It uses arsenic adsorption on an Indian-made Nirmal: 80- activated alumina and it is followed by filtration 90% arsenic through a ceramic candle. It is less expensive than removal a Magc-Alcan filter ($10-15 capital cost) but it needs to be regenerated every 6 months. Efficiency: 80-90% arsenic removal. Household Water Treatment for Arsenic Removal Fact Sheet: Adsorption Shapla Filter Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Arsenic  Turbidity What Is a Shapla Filter? The Shapla filter is an earthen household arsenic removal technology developed by International Development Enterprises (IDE), Bangladesh. It is based on adsorption (adhesion or sticking together) of the arsenic to the iron on the coated brick chips, which works as well as iron coated sand. The bricks are coated by treatment with a ferrous sulphate solution (Ahmed, 2005). The filter can hold up to 30 litres of water. How Does It Remove Arsenic? As water passes through the filter, arsenic from the water is rapidly adsorbed by the iron on the brick chips. The media (20 kg) filters 4,000 litres of arsenic-contaminated water reducing arsenic concentrations to undetectable levels and supplying an average family with 25-32 litres of safe drinking water per day. Operation (Photo Credit: Ngai) Pour the water into the filter and allow it to pass through the filter medium. Key Information Efficiency Production Cost Lifespan The used filter media is non-toxic and can be $10 capital disposed of safely without danger to the cost Short media environment or human health. The media container 80-90% 25-32 $10-15 lifespan (3-6 is re-useable and easily maintained. arsenic litres/day media months) removal replacement cost/year Household Water Treatment for Arsenic Removal Fact Sheet: Adsorption References Ontario Centre for Environmental Technology Advancement. Assessment of five technologies for mitigating arsenic in Bangladesh well water. Environmental Technology Verification-Arsenic Mitigation, Arsenic Mitigation Based on an Agreement between the Governments of Canada and Bangladesh. Available at: www.physics.harvard.edu/~wilson/arsenic/remediation/ETVAM%20Poster.ppt Sutherland D, (2001). Rapid assessment of household level arsenic removal technologies: Phase II Executive Summary. Water Aid Bangladesh, Bangladesh Arsenic Mitigation Water Supply Project. Available at: www.wateraid.org/documents/phs2execsum.pdf Phase I Report: www.wateraid.org/documents/phs1report.pdf Phase II Report: www.wateraid.org/documents/phs2fullrpt.pdf World Bank, Water and Sanitation Program (2005). Towards a more effective operational response: Arsenic contamination of groundwater in South and East Asia countries, Volumes I & II. Available at: http://web.worldbank.org/WBSITE/EXTERNAL/COUNTRIES/SOUTHASIAEXT/EXTSAREGTOPWATRES/0,,co ntentMDK:20450010~pagePK:34004173~piPK:34003707~theSitePK:494236,00.html Further Information Magc-Alcan Filter: www.buet.ac.bd/itn/pages/outcomes/ALCAN%20WSP%20Jul%2001_2007%20v1.pdf www.wateraid.org/documents/plugin_documents/arsenicweb.pdf http://books.google.ca/books?id=Mo9Btfy95H0C&pg=PA41&lpg=PA41&dq=alcan+household+filter+description &source=bl&ots=tdH8hr1kfp&sig=uIPcNRy3ifGTPrTwUQRnwofBxhc&hl=en&ei=xgasSZuOMZqqtQP2sOD3Dw &sa=X&oi=book_result&resnum=4&ct=result#PPA42,M1 Shapla Filter: www.jalmandir.com/arsenic/shapla/shapla-arsenic-filter.html CAWST (Centre for Affordable Water and Sanitation Technology) Wellness through Water.... Empowering People Globally Calgary, Alberta, Canada Website: www.cawst.org Email: [email protected] Last Update: October 2009 Household Water Treatment for Arsenic Removal Fact Sheet: Coagulation-Flocculation Bucket Treatment Unit (BTU) Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Most pathogens  Arsenic  Chemicals  Turbidity  Taste, odour, colour What Is Bucket Treatment Unit (BTU)?  2 mg/L of potassium permanganate The Bucket Treatment Unit has been developed The mixture is then allowed to settle for 1-2 hours. within the DPHE-Danida project. It consists of The tap is then turned on so that the water can oxidation (loss of electrons of As(III) to form As(V)) pass through a cloth screen and a sand filter in the and coagulation (clumping of particles to promote lower bucket. sedimentation) processes using potassium permanganate and aluminum sulphate respectively. The water is then filtered through cloth into a second bucket that contains a sand filter. The BTU can be constructed from locally available materials. How Does It Remove Arsenic? Arsenic is removed by:  The oxidation of As(III) to As(V) by applying an oxidizing agent (potassium permanganate)  Coagulation and flocculation by applied flocculant (alum)  Adsorption of arsenic on flocs  Sedimentation  Cloth and sand filtration. Coagulation/flocculation can also be obtained by iron chloride/iron sulfate. Operation (Photo Credit: Ngai) The unit consists of a two bucket system. The upper bucket is filled with raw water. Chemicals are Key Information added and the water is stirred fast for approximately Treatment 25 seconds with a wooden spoon provided with the Production Cost Efficiency unit. $10 capital cost ~ 60% arsenic Recommended chemical doses are (Tanhura et 20 litres/hour $15-20 chemical removal al.): cost/year  200 mg/L aluminum sulphate Household Water Treatment for Arsenic Removal Fact Sheet: Coagulation-Flocculation 2-Kolshi Filter Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Arsenic  Chemicals  Pathogens  Taste, odour, colour What Is 2-Kolshi? 2-Kolshi is an arsenic removal method using two buckets. The first step is a coagulation process using a specific amount of iron sulphate and enough sodium hypochlorite to create a distinctive chlorine odour upon stirring in a normal bucket of water, followed by a filtration in a ceramic filter. How Does It Remove Arsenic? Coagulation/filtration is a traditional treatment process that adds a chemical coagulant (typically iron sulfate or iron chloride) to contaminated water. The coagulant modifies the physical or chemical properties of dissolved or suspended contaminants so that they settle from solution by gravity or can be removed by filtration. As part of the coagulation process, arsenic is co-precipitated with the iron. The stirring process helps to build the flocs into larger particles. The 2-Kolshi technique oxidizes As(III) to As(V) by stirring the water, co-precipitates As5+ with iron chloride and ash, and then it filters the water to (Photo Credit: Ngai) remove the formed particles. Key Information Operation Treatment Production Cost  Add ENPHO chemical (iron sulphate, sodium Efficiency hypochlorite and ash) to a bucket of water 90% arsenic removal $10 capital cost  Stir water for a few minutes 99% microbial 3-5 litres/hour $15-20 chemical removal cost/year  Let settle for one hour  Pass the water through a ceramic filter Household Water Treatment for Arsenic Removal Fact Sheet: Coagulation-Flocculation References Hwang, S.K. (2002). Point-of-use arsenic removal from drinking water in Nepal using coagulation and filtration. MIT Master of Engineering Thesis. June 2002 Sutherland D, (2001). Rapid assessment of household level arsenic removal technologies: Phase II Executive Summary. Water Aid Bangladesh, Bangladesh Arsenic Mitigation Water Supply Project. Available at: www.wateraid.org/documents/phs2execsum.pdf. Phase I Report: www.wateraid.org/documents/phs1report.pdf Phase II Report: www.wateraid.org/documents/phs2fullrpt.pdf Further Information Bucket Treatment Unit (BTU): www.unu.edu/env/arsenic/tahura.pdfhttp://www.asce-susdev.org/files/pdf/efsdec07.pdf www.ubu.dk/Arsenic%20project/household_treatment.htm#bucket%20treatment%20unit 2-Kolshi Filter: www.epa.gov/etv/pubs/600s07007.pdf www.betv-sam.org/documents/nepal_workshop/presentations/11- TNgai_FindingsonArsenicMitigationTechnologiesTestingandEvaluationinNepal.pdf CAWST (Centre for Affordable Water and Sanitation Technology) Wellness through Water.... Empowering People Globally Calgary, Alberta, Canada Website: www.cawst.org Email: [email protected] Last Update: Oxtober 2009 Household Water Treatment for Arsenic Removal Fact Sheet: Surface Complexation Sono Filter Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Arsenic  Bacteria  Turbidity  Chemicals  Taste/odour/colour What Is a Sono Filter?  Top bucket: 3 kg iron filings and 2 kg coarse sand The Sono Filter is a three bucket system  Middle bucket: 2 kg fine sand, 1 kg of with a composite iron matrix (CIM) as the wood charcoal and brick chips active arsenic removal component. It  Bottom bucket: water collection creates surface complexation of arsenic on container the CIM followed by a filtration. The water first flows through the coarse river The filter is manufactured from indigenous sand and a composite iron matrix (CIM). The materials and it works without chemical water flows into a second bucket where treatment, without regeneration, and without it again filters through coarse river sand, producing toxic waste. It is efficient to remove arsenic and 22 other heavy metals then wood charcoal to remove organics, and as well as bacteria. finally through fine river sand and brick chips to remove fine particles and stabilize water flow. How Does It Remove Arsenic? The primary active material is the composite iron matrix (CIM) made of cast iron. Manganese in CIM catalyzes oxidation of As(III) to As(V), all of which is removed by a surface-complexation reaction between the surface of hydrated iron (FeOH ) and arsenic species thereby removing the arsenic from the water. FeOH is also known to remove many other toxic species. In combination with CIM, the sand, charcoal and the optimum arrangement of the materials in the filter removes arsenic, iron, manganese and many other inorganic species to a potable water quality. Operation Each bucket has different media and functions: (Photo Credit: www.robrasa.com) Household Water Treatment for Arsenic Removal Fact Sheet: Surface Complexation Key Information Treatment Production Cost Lifespan Efficiency 90-95% 20-30 litres per hour $40-50 capital cost Replace unit after 3-5 years arsenic removal References Sutherland D (2001). Rapid assessment of household level arsenic removal technologies: Phase II Executive Summary. Water Aid Bangladesh, Bangladesh Arsenic Mitigation Water Supply Project. Available at: www.wateraid.org/documents/phs2execsum.pdf Phase I Report: www.wateraid.org/documents/phs1report.pdf Phase II Report: www.wateraid.org/documents/phs2fullrpt.pdf Munir, A.K., S.B. Rasul, M. Habibuddowla, M. Alauddin, A. Hussam and A.H. Khan. Evaluation of performance of Sono 3-Kolshi Filter for arsenic removal from groundwater using zero valent iron through laboratory and field studies. Bangladesh University of Engineering and Technology, Dhaka and The United Nations University, Tokyo. Available at: www.unu.edu/env/arsenic/Munir.pdf Ontario Centre for Environmental Technology Advancement. Assessment of five technologies for mitigating arsenic in Bangladesh well water. Environmental Technology Verification-Arsenic Mitigation, Arsenic Mitigation Based on an Agreement between the Governments of Canada and Bangladesh. Available at: www.physics.harvard.edu/~wilson/arsenic/remediation/ETVAM%20Poster.ppt Further Information http://robjkentjr.blogspot.com/2008/07/sono-water-filter-for-removing-arsenic.php www.asce-susdev.org/files/pdf/efsdec07.pdf www.robrasa.com/files/sono_filter_study.pdf www.physics.harvard.edu/~wilson/arsenic/remediation/SONO/Narrative_Grainger_AH.pdf CAWST (Centre for Affordable Water and Sanitation Technology) Wellness through Water.... Empowering People Globally Calgary, Alberta, Canada Website: www.cawst.org Email: [email protected] Last Update: October 2009 Household Water Treatment for Arsenic Removal Fact Sheet: Surface Complexation TM Kanchan Arsenic Filter Potential Treatment Capacity Very Effective For: Somewhat Effective For: Not Effective For:  Arsenic  Viruses  Chemicals  Bacteria  Iron  Protozoa  Helminths  Turbidity  Taste/odour/colour How Does it Remove Contamination? What is a KanchanTM Arsenic Filter? Arsenic from the water is rapidly adsorbed The KanchanTM Arsenic Filter (KAF) is an onto the rust on the iron nails. The rust and adaptation of the biosand filter (BSF). The arsenic flake off the nails, and are caught in KAF has been designed to remove arsenic the sand filter and retained. This is a very from drinking water, in addition to providing tight bond; re-suspension of arsenic into the microbiological water treatment. Arsenic water, or re-mobilization of the arsenic from removal is achieved by incorporating a layer the waste produced from cleaning the filter of rusty nails in the diffuser basin of the filter. has shown to be negligible. The filter container can be constructed out of concrete or plastic. The container is about 0.9 m tall and either 0.3 m square or 0.3 m in diameter. 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. . The diffuser basin is filled with 5 to 6 kg of non-galvanized iron nails for arsenic removal. A layer of bricks on top of the nails Cross-Section of KanchanTM Arsenic Filter prevents displacement of the nails when water is poured into the filter. Household Water Treatment for Arsenic Removal Fact Sheet: Surface Complexation In addition, pathogens, iron and suspended than 5 cm results in lower oxygen diffusion material are removed from water through a to the biolayer. A water depth less than 5 cm combination of biological and physical may evaporate quickly in hot climates and processes. These occur both in both the cause the biolayer to dry out. biolayer and within the sand bed. These processes include: mechanical trapping, A pause period is needed between uses to adsorption/attraction, predation and natural allow time for the microorganisms in the death. biolayer to consume pathogens in the water. Users should wait at least one hour after all Operation the water has been filtered before filling the Contaminated water is poured into the top of filter again. It is recommended to use the the filter on an intermittent basis. The water filter every day; however users can wait up slowly passes through the diffuser, and to a maximum of 48 hours between batches. percolates down through the biolayer, sand The KAF has been designed to allow for a and gravel. Treated water naturally flows filter loading rate (flow rate per square metre from the outlet. of filter area) which has proven to be effective in laboratory and field tests. This The rusted iron nails are essential for filter loading rate has been determined to be removing arsenic. The nails need to be not more than 600 litres/hour/square metre. evenly distributed to avoid the water from short-circuiting. A layer of bricks on top of The recommended flow rate for the CAWST the nails prevents displacement of the nails Version 10 concrete KAF is 0.4 L/minute when water is poured into the filter. As well, measured when the inlet reservoir is full of users should pour the water slowly and water. If the flow rate is much faster, the carefully into the filter to prevent the nails filter may become less efficient at removing from moving around. pathogens. If the flow rate is much slower, the user may become impatient and not use The biolayer is the key pathogen removing the filter even though the filter is working component of the filter. Without it, the filter is well at removing pathogens. Since the flow significantly less effective. It may take up to rate is controlled by the size of the sand 30 days to establish the biolayer depending grains, it is very important to select, sieve on inlet water quality and frequency of use. and wash the sand properly. The water from the filter can be used during The KAF requires maintenance when the the first few weeks while the biolayer is flow rate drops to a level that is inadequate being established, but disinfection is for the household use. This is done by a recommended during this time, as during simple ‘swirl and dump’ procedure regular on-going use. performed on the top of the sand, and only takes a few minutes. The biolayer requires oxygen to survive. When water is flowing through the filter, The outlet should also be cleaned regularly dissolved oxygen in the water is supplied to using soap and water or a chlorine solution. the biolayer. During pause times, when the water is not flowing, the oxygen is obtained The treated water should be collected by the by diffusion from the air. user in a safe storage container placed on a block or stand, so that the container opening Correct installation and operation of the is just under the outlet, minimizing the risk biosand filter has a water level of for recontamination. approximately 5 cm above the sand during the pause period. A water depth of greater