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Module
1.9 1.9 The Safe Storage of Water
Studies have shown that even if water is microbiologically safe when put in storage containers, it can be quickly contaminated during storage and use. Typical containers are often kept uncovered and do not adequately protect water. This module will point out appropriate containers and safe water use.
Page 1 of 6
1.9 THE SAFE STORAGE OF WATER......................................................................................................1 SYSTEMS FOR HOUSEHOLD STORAGE OF COLLECTED WATER TO PROTECT MICROBIOLOGICAL QUALITY......................2 DESIRED CHARACTERISTICS FOR SAFE WATER STORAGE VESSEL .......................................................................4 RESOURCES.............................................................................................................................................4 WATER STORAGE: narrow-necked pitchers reduce contamination....................................................4 CDC Safe Water System.........................................................................................................................4 OXFAM’s Bucket....................................................................................................................................6 Commercially Available Containers......................................................................................................6
Systems for Household Storage of Collected Water to Protect Microbiological Quality A review of the existing literature on collection and storage of household water revealed that such water often comes from fecally contaminated sources and therefore poses infectious disease risks to consumers. Furthermore, regardless of whether or not collected household water is initially of acceptable microbiological quality, it often becomes contaminated with pathogens of fecal origin during transport and storage due to unhygienic storage and handling practices. Studies show that the use of containers with narrow openings for filling and dispensing devices such as spouts or taps/spigots, protect the collected water during storage and household use. Many container designs also have handles, are lightweight, are made from durable UV-resistant plastic, and are affixed with a label containing informational and educational material on their cleaning and use. Other appropriate containers for safe storage are those in which water can be directly treated by the physical method of solar radiation and then directly stored and dispensed for household use. These improved containers protect stored household water from the introduction of microbial contaminants via contact with hands, dippers, other fecally contaminated vehicles or the intrusion of vectors. http://www.who.int/water_sanitation_health/dwq/wsh0207/en/index3.html (Apr 05) Proper containers help preserve water quality after treatment. The user has gone through a lot of work to collect water from a source, transport it to the home and then filter it through the filter. Now that the water is clean, all precautions should be taken to ensure that it now remains clean. The best way to do this is to use an appropriate container. • Provide a proper container (not an open bucket) for clean water. Never use it for dirty water. • Provide a bucket for dirty water and use it only for dirty water. • Once the dirty water has passed through the BioSand filter, it is recommended to add 4 drops of bleach per litre of filtered water to ensure the highest possible quality water. In many cases this may not be necessary, but it is a precaution to ensure disinfected water. Also, residual chlorine in a closed container protects against recontamination.
Module 1.9 The Safe Storage of Water •
Now that good quality water is available to the users, combine it with changes in human behaviour through education. It is crucial to improve the hygiene practices of the water users.
Page 3 of 6
Module 1.9 The Safe Storage of Water
Desired Characteristics for Safe Water Storage Vessel •
• • • •
•
•
Appropriate shape and volume (e.g. 10 - 30 Litres), stable base, sturdy comfortable handle, smaller for children Durable, light weight, non oxidizing, translucent, easy to clean, inexpensive and locally produced High density polyethylene plastic or similar with ultra violet absorbers
• • • • •
Single opening of 5-9 cm ( 2-3”) diameter with a strong, tightly fitting cover o easy to fill but difficult to immerse hands or utensils Non rusting, durable, cleanable spigot or spout for extracting water - 1 L in about 15 seconds Allow air to enter as water is extracted Have volume indicators and illustrations for safe waterhandling practices on the vessel Stamped, sticker permanently fixed Consider local demand for shape, volume, colour and material enhance the appeal Cost: about USD $3.00 - $8.00 for CDC and OXFAM vessels Certificate that it complies with requirements of Ministry of Health or equivalent authority
Resources WATER STORAGE: narrow-necked pitchers reduce contamination Microbiological water quality is significantly better in narrow-necked pitchers than in traditional wide-necked pitchers, according to a study conducted in 67 households in the southern Punjab region of Pakistan, using surface or open-well water. There was, however, no difference between the two storage types if the water at the source was already of relatively poor quality or if extreme faecal pollution occurred during the filling and washing of the pitchers. The study was carried out by researchers from the International Water Management Institute, Sri Lanka, as part of a wider investigation into the impact of using irrigation water for domestic purposes in Pakistan. http://www.id21.org/urban/h10sc2g2.html (Apr 05) CDC Safe Water System The Center for Disease Control (CDC) in Atlanta Georgia has done an extensive program over the last seven years to develop a household chlorination program which is called the Safe Water System. Their web site is excellent in describing the system and has many educational tools. A major component of the Safe Water System is the use of an
Page 4 of 6
Module 1.9 The Safe Storage of Water appropriate container for treated water based on research that showed that recontamination frequently occurs when inappropriate containers were used. http://www.cdc.gov/safewater (Apr 05) •
• •
CDC Safe Water System program manual o Section 5.3: Choosing a vessel for water storage in the home o Annex D Item D: Worksheet for assessing possible household water storage vessels There is also an 11 minute video on the safe water system which shows the CDC water container The CDC web site also has current information on manufacturers of vessels and molds for building plastic containers
The following was taken from the CDC Safe Water System manual which describes the experience of the CDC with their appropriate container efforts: “Various containers were evaluated by both PAHO (Pan American Health Organization) and CDC. Several were found in the United States that complied with almost all of the requirements and they were purchased and shipped to the initial demonstration projects in Latin America. As part of the project, after practical use, they were evaluated by both health officials and participants for suitability, durability, ease of use, preferable volume and the design features listed earlier. Because the cost of shipping long distances is almost equal to the cost of the container, the need for local manufacture was apparent.” “In Bolivia all of the containers have been 5 gallon or 20 litre polyethylene containers that were manufactured in the United States, but the mold has been sold to a local manufacturer so they can be produced in Bolivia. Local production is scheduled to commence in 1996 and, depending upon public acceptance, may be mass produced to serve the entire country. In the Dominican Republic, Nicaragua and Colombia the same 20 litre containers have been used, but in Colombia a 55 gallon ferrocement container which was produced locally was also tested. In Colombia, the GTZ is also financing a project in the private sector to design and produce a trial run of suitable plastic containers. In Guatemala and in Ecuador the containers were produced by retrofitting locally manufactured plastic containers with faucets. In Peru several designs have been produced and manufactured commercially, but all have a capacity of 20 litres.” “In Bolivia, Colombia and Nicaragua a small percentage of the participating households were also provided with a locally fabricated sand filter to pretreat the water before its disinfection in the house hold containers. Such pretreatment does increase the efficiency of disinfection and improve the aesthetic quality of the water.”
Page 5 of 6
Module 1.9 The Safe Storage of Water OXFAM’s Bucket Another highly recommended container is the OXFAM Bucket. The importance of having a water container in an emergency situation cannot be over estimated. Often, refugees fleeing from conflict will arrive in a refugee camp or a village with virtually no possessions. One of the first activities they will need to carry out is the collection of water. Therefore, the rapid distribution of water containers in emergency situations is crucial, which is why Oxfam’s Technical Unit has developed a more appropriate design of water container than previously used. http://oxfam.org.uk/what_we_do/emergencies/how_we_work/factfile/oxfam_bucket.htm (Apr 05)
The following information was obtained from OXFAM regarding pricing and specs for their bucket: Pallet of 200 Units Pallet GW: 220 kg Volume: 1.440 m3 Pack dimensions: 120 × 120 × 100 cm Item 1.
Qty 1 pallet
Description 200 stackable 14 litre water containers with taps. Specialised features are: • 14 litre capacity, removable tight-fit lid • Opening in lid with a cap attached • 190 Plastic taps one at the bottom of each container & 10 spare • Plastic handle attached • Bottom ridge ovalling • Reinforced top • Tough durable UV treated plastic (suitable for food & drinking water) • Curved inside base to wall join for easy cleaning
The price of the water container is £2.62 for sale to other agencies (i.e. £529 per pallet of 200 water containers). Pallets cannot be split. Commercially Available Containers There are commercially available water containers which can be purchased in many places throughout North America. Many of these can be found in camping or outdoor retail stores or through dealers that handle camping equipment. The following is one such container and the supplier.
http://www.forestry-suppliers.com/product_pages/view_catalog_page.asp?ID=6044 (Apr 05)
Page 6 of 6
1.9 1.9 The Safe Storage of Water
Studies have shown that even if water is microbiologically safe when put in storage containers, it can be quickly contaminated during storage and use. Typical containers are often kept uncovered and do not adequately protect water. This module will point out appropriate containers and safe water use.
Page 1 of 6
1.9 THE SAFE STORAGE OF WATER......................................................................................................1 SYSTEMS FOR HOUSEHOLD STORAGE OF COLLECTED WATER TO PROTECT MICROBIOLOGICAL QUALITY......................2 DESIRED CHARACTERISTICS FOR SAFE WATER STORAGE VESSEL .......................................................................4 RESOURCES.............................................................................................................................................4 WATER STORAGE: narrow-necked pitchers reduce contamination....................................................4 CDC Safe Water System.........................................................................................................................4 OXFAM’s Bucket....................................................................................................................................6 Commercially Available Containers......................................................................................................6
Systems for Household Storage of Collected Water to Protect Microbiological Quality A review of the existing literature on collection and storage of household water revealed that such water often comes from fecally contaminated sources and therefore poses infectious disease risks to consumers. Furthermore, regardless of whether or not collected household water is initially of acceptable microbiological quality, it often becomes contaminated with pathogens of fecal origin during transport and storage due to unhygienic storage and handling practices. Studies show that the use of containers with narrow openings for filling and dispensing devices such as spouts or taps/spigots, protect the collected water during storage and household use. Many container designs also have handles, are lightweight, are made from durable UV-resistant plastic, and are affixed with a label containing informational and educational material on their cleaning and use. Other appropriate containers for safe storage are those in which water can be directly treated by the physical method of solar radiation and then directly stored and dispensed for household use. These improved containers protect stored household water from the introduction of microbial contaminants via contact with hands, dippers, other fecally contaminated vehicles or the intrusion of vectors. http://www.who.int/water_sanitation_health/dwq/wsh0207/en/index3.html (Apr 05) Proper containers help preserve water quality after treatment. The user has gone through a lot of work to collect water from a source, transport it to the home and then filter it through the filter. Now that the water is clean, all precautions should be taken to ensure that it now remains clean. The best way to do this is to use an appropriate container. • Provide a proper container (not an open bucket) for clean water. Never use it for dirty water. • Provide a bucket for dirty water and use it only for dirty water. • Once the dirty water has passed through the BioSand filter, it is recommended to add 4 drops of bleach per litre of filtered water to ensure the highest possible quality water. In many cases this may not be necessary, but it is a precaution to ensure disinfected water. Also, residual chlorine in a closed container protects against recontamination.
Module 1.9 The Safe Storage of Water •
Now that good quality water is available to the users, combine it with changes in human behaviour through education. It is crucial to improve the hygiene practices of the water users.
Page 3 of 6
Module 1.9 The Safe Storage of Water
Desired Characteristics for Safe Water Storage Vessel •
• • • •
•
•
Appropriate shape and volume (e.g. 10 - 30 Litres), stable base, sturdy comfortable handle, smaller for children Durable, light weight, non oxidizing, translucent, easy to clean, inexpensive and locally produced High density polyethylene plastic or similar with ultra violet absorbers
• • • • •
Single opening of 5-9 cm ( 2-3”) diameter with a strong, tightly fitting cover o easy to fill but difficult to immerse hands or utensils Non rusting, durable, cleanable spigot or spout for extracting water - 1 L in about 15 seconds Allow air to enter as water is extracted Have volume indicators and illustrations for safe waterhandling practices on the vessel Stamped, sticker permanently fixed Consider local demand for shape, volume, colour and material enhance the appeal Cost: about USD $3.00 - $8.00 for CDC and OXFAM vessels Certificate that it complies with requirements of Ministry of Health or equivalent authority
Resources WATER STORAGE: narrow-necked pitchers reduce contamination Microbiological water quality is significantly better in narrow-necked pitchers than in traditional wide-necked pitchers, according to a study conducted in 67 households in the southern Punjab region of Pakistan, using surface or open-well water. There was, however, no difference between the two storage types if the water at the source was already of relatively poor quality or if extreme faecal pollution occurred during the filling and washing of the pitchers. The study was carried out by researchers from the International Water Management Institute, Sri Lanka, as part of a wider investigation into the impact of using irrigation water for domestic purposes in Pakistan. http://www.id21.org/urban/h10sc2g2.html (Apr 05) CDC Safe Water System The Center for Disease Control (CDC) in Atlanta Georgia has done an extensive program over the last seven years to develop a household chlorination program which is called the Safe Water System. Their web site is excellent in describing the system and has many educational tools. A major component of the Safe Water System is the use of an
Page 4 of 6
Module 1.9 The Safe Storage of Water appropriate container for treated water based on research that showed that recontamination frequently occurs when inappropriate containers were used. http://www.cdc.gov/safewater (Apr 05) •
• •
CDC Safe Water System program manual o Section 5.3: Choosing a vessel for water storage in the home o Annex D Item D: Worksheet for assessing possible household water storage vessels There is also an 11 minute video on the safe water system which shows the CDC water container The CDC web site also has current information on manufacturers of vessels and molds for building plastic containers
The following was taken from the CDC Safe Water System manual which describes the experience of the CDC with their appropriate container efforts: “Various containers were evaluated by both PAHO (Pan American Health Organization) and CDC. Several were found in the United States that complied with almost all of the requirements and they were purchased and shipped to the initial demonstration projects in Latin America. As part of the project, after practical use, they were evaluated by both health officials and participants for suitability, durability, ease of use, preferable volume and the design features listed earlier. Because the cost of shipping long distances is almost equal to the cost of the container, the need for local manufacture was apparent.” “In Bolivia all of the containers have been 5 gallon or 20 litre polyethylene containers that were manufactured in the United States, but the mold has been sold to a local manufacturer so they can be produced in Bolivia. Local production is scheduled to commence in 1996 and, depending upon public acceptance, may be mass produced to serve the entire country. In the Dominican Republic, Nicaragua and Colombia the same 20 litre containers have been used, but in Colombia a 55 gallon ferrocement container which was produced locally was also tested. In Colombia, the GTZ is also financing a project in the private sector to design and produce a trial run of suitable plastic containers. In Guatemala and in Ecuador the containers were produced by retrofitting locally manufactured plastic containers with faucets. In Peru several designs have been produced and manufactured commercially, but all have a capacity of 20 litres.” “In Bolivia, Colombia and Nicaragua a small percentage of the participating households were also provided with a locally fabricated sand filter to pretreat the water before its disinfection in the house hold containers. Such pretreatment does increase the efficiency of disinfection and improve the aesthetic quality of the water.”
Page 5 of 6
Module 1.9 The Safe Storage of Water OXFAM’s Bucket Another highly recommended container is the OXFAM Bucket. The importance of having a water container in an emergency situation cannot be over estimated. Often, refugees fleeing from conflict will arrive in a refugee camp or a village with virtually no possessions. One of the first activities they will need to carry out is the collection of water. Therefore, the rapid distribution of water containers in emergency situations is crucial, which is why Oxfam’s Technical Unit has developed a more appropriate design of water container than previously used. http://oxfam.org.uk/what_we_do/emergencies/how_we_work/factfile/oxfam_bucket.htm (Apr 05)
The following information was obtained from OXFAM regarding pricing and specs for their bucket: Pallet of 200 Units Pallet GW: 220 kg Volume: 1.440 m3 Pack dimensions: 120 × 120 × 100 cm Item 1.
Qty 1 pallet
Description 200 stackable 14 litre water containers with taps. Specialised features are: • 14 litre capacity, removable tight-fit lid • Opening in lid with a cap attached • 190 Plastic taps one at the bottom of each container & 10 spare • Plastic handle attached • Bottom ridge ovalling • Reinforced top • Tough durable UV treated plastic (suitable for food & drinking water) • Curved inside base to wall join for easy cleaning
The price of the water container is £2.62 for sale to other agencies (i.e. £529 per pallet of 200 water containers). Pallets cannot be split. Commercially Available Containers There are commercially available water containers which can be purchased in many places throughout North America. Many of these can be found in camping or outdoor retail stores or through dealers that handle camping equipment. The following is one such container and the supplier.
http://www.forestry-suppliers.com/product_pages/view_catalog_page.asp?ID=6044 (Apr 05)
Page 6 of 6
