Tunsai (Rabbit) Ceramic Water Purifier

Hydrologic

Snapshot
Manufacturing & delivery
Performance & use
Research & standards
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Product description Brand name and product description

Tunsai Ceramic Water Purifier are silver enhanced ceramic ‘pot’ water filters for household drinking water treatment manufactured in Cambodia based on the open source technology promoted by Potters for Peace.

Target region(s) Target region for distribution/implementation (listed by country if specified)

Cambodia

Distributors/implementing organizations Organization(s) distributing/deploying this product directly to communities/individuals?"

Distribution is through NGO channels and through a network of retailers.

Market suggested retail price Price per unit or service price per usage/terms (USD). Subsidies noted.

Two models are produced by Hydrologic, the ‘Tunsai’ (rabbit) which retails for about US$13.50 and the ‘Super Tunsai’ which retails for US$23.50. US$1 = 4,000 Cambodian riel (March 2011). For village sales, VisionFund loans for water filters are charged at 2.8% per month for 6 months, and the VisionFund agent visits each month to collect payments.

Competitive landscape Similar products available on the market. May not be a comprehensive listing.

Household water treatment methods and products available in local market, including Resource Development International – Cambodia (RDIC) and Engineers Without Borders Australia (EWB Australia) – RDIC Ceramic Water Filter

SDG targeted United Nations Sustainable Development Goals (SDGs) targeted with this product/application/service

SDG #6: Clean water and sanitation

Target user(s) Target user/consumer base (country, income segment)

Targeted at Cambodian households without access to potable water, earning between US$1-$5 per person per day.

Manufacturing/building method(s) Detail regarding solution production or construction method (instructions, mass production capacity, custom made,etc...)

Locally sourced clay and rice husk are processed then mixed with water, pressed into the filter shape, fired to a ceramic state, flow rate tested to ensure production consistency and coated with silver nitrate solution.

Product Intellectual Property Open source/IP protected (note patent)/trade secret/other?

Open source

User Provision Model Where can the product be purchased/acquired by end users?

Users can obtain filters through a network of 600 retail centers throughout the (Cambodian) provinces. Sales averaged about 26,000 per year from 2006 to 2010, but increased to nearly 47,000 in 2011 with the new factory working near full capacity (4,000 pots per month) and the launch of the Super Tunsai and the direct sales network

Village-to-village water filter sales. Hydrologic recruits and trains commissioned sales agents, each of whom coordinates with village chiefs to arrange group sales meetings in about 20 villages per month.

Hydrologic can also arrange to export Tunsai water filters to countries around the world. To date, Hydrologic have exported to resellers in Yemen, Sri Lanka and Vietnam.

Distribution to date Number of units that have been deployed, downloads or users to date

>450,000

Fields marked are sourced values that have been evaluated by the manufacturer or a third party, all others are design specifications.

Filter materials

Filters are manufactured with clay, rice husk and silver nitrate

Dirty water volume

Bacteria removed (logarithmic scale)

6 log

Turbidity (NTU)

99%

Safe water storage capacity (L)

~14

Number of spigots

Filter lifespan (years)

~2 years

Filter design capacity

~20,000 L

Average flow rate per hour

2-3 L/hr when full

Average flow rate per day

~30 liters, depending on pattern of use

Maintenance Schedule

How often/when should maintenance be performed?

Scrub filter when flow rate slows.

Chemical residual

There is a potential for silver in filtered water, below secondary guideline values of 0.1 mg/L.

End of life indicator (yes/no)

Replace filter if it breaks, there are visible cracks or chips, or filtration rate does not rejuvenate to a satisfactory rate after scrubbing.

Design specifications Component and Operation overview including power, portability, facility requirements, preventative maintenance and user training requirements

Tunsai Ceramic Water Purifier consist of a porous 10 L capacity ceramic filtering element that suspends in a food grade, pigment-free plastic receptacle that stores and dispenses filtered water. Filter membrane weighs: 4.6 kg; Flow rate is 2.5 – 4.5 litre/hour when full.

Product schematics Design and assembly illustrations

Unavailable

Technical support Technical support provided by

To rejuvenate flow rate when filters clog, users scrub ceramic filtering element with a brush. Instructions provided with the unit.

Replacement components Availability of replacement components (in-country, by order,...)

Available in country: tap for dispensing water, safe storage container, ceramic filtering element.

Lifecycle Disposal and warranty

The average service life of a filter in day-to-day use has been measured as two years. The plastic receptacle and spigot last for five years. Lifespan depends on the quality of the input water and the care taken to avoid breakage.

Manufacturer specified performance targets Designer / Manufacturer specified targets

4 log reduction in bacteria, 2-3 liter per hour flow rate.

Vetted performance Findings of manufacturer evaluations or independent testing centers

Filtered water tested by the Ministry of Health and meets World Health Organization guidelines for clean drinking water. Laboratory tests confirm effectiveness in supplying water with less than 10 E.coli bacteria per 100 ml

Testing organizations Independent lab, academic research centers, etc.

WaterSHED laboratory in Phnom Penh

Safety Potential hazards / risks related to operation of this product

Unknown

Complementary technical systems Performance of this product is improved with another technology (eg. Cookstoves and Wind-blocking skirts)

Pre-filter or settle very turbid water (> 5NTU)

Academic research Academic research related to the product (e.g. published papers in peer-reviewed journals)

Joe Brown Study that looks at all ceramic Water In Cambodia and Sustained use of a household-scale water filtration device in rural Cambodia Joe Brown, S. Proum and M. D. Sobsey; Field test of a silver-impregnated ceramic water filter, M.
Roberts, Cambodia

Compliance with regulations Product certifications and standards referenced by designer/manufacturer

None referenced by the manufacturer.

Known requirements, NSF Protocol P231 established minimum requirements for health and sanitation characteristics of microbiological water purifiers. The requirements are based on the recommendations of the U.S. Environmental Protection Agency’s Task Force Report, Guide Standard and Protocol for Testing Microbiological Water Purifiers (1987) (Annex B).

Evaluation methods Evaluation methods/protocols/guidelines referenced by designer or manufacturer.

United States Environmental Protection Agency Methods 1602 (EPA 2001) and 1622(EPA 2005)(“Implementer feedback: Rachel Pringle – Implementer – iDE Cambodia”)

21st edition of Standard Methods for the Examination of Water and Wastewater (American Public Health Association [APHA], American Water Works Association [AWWA], & Water Environment Federation [WEF] 2005) ^2

Best Practice Recommendations for Local Manufacturing of Ceramic Pot Filters for Household Water Treatment ^not ^peer ^reviewed

Other information

This filter cannot remove arsenic, or other chemical contaminants from water. As a result, this is not a good device for arsenic contaminated well water (it is best used in Cambodia for rain and surface water.) Not time efficient for purifying large quantities of water. Ashden Award winner 2012

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Tunsai (Rabbit) Ceramic Water Purifier

Hydrologic

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