Household Water Treatment and Storage

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Historically, interventions to provide people with safe water have focussed on improving water sources. However there is now a consensus among the WatSan community that even if the drinking water source is safe it can easily be re-contaminated during its transportation and storage in the household (Clasen and Bastable, 2003). A safe water intervention should therefore begin with an improved water supply and be followed by safe water collection, handling and storage. In circumstances where the source is not deemed safe, point of use water treatment should be performed. All of these should be coupled with hygiene promotion activities to ensure correct understanding, use and maintenance of the hardware. This technical brief presents the current options for safe storage and point of use water treatment. It is intended to help field staff working in a variety of locations to decide upon the most appropriate course of action for providing safe water for the communities in which they work. The effectiveness of household water treatment options now and in the future rely to a huge extent on user compliance
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  HOUSEHOLD WATER TREATMENT AND STORAGE Historically, interventions to provide people with safe water have focussed on improving water sources. However there is now a consensus among the WatSan community that even if the drinking water source is safe it can easily be re-contaminated during its transportation and storage in the household (Clasen and Bastable, 2003). A safe water intervention should therefore begin with an improved water supply and be followed by safe water collection, handling and storage. In circumstances where the source is not deemed safe, point of use water treatment should be performed. All of these should be coupled with hygiene promotion activities to ensure correct understanding, use and maintenance of the hardware. This technical brief presents the current options for safe storage and point of use water treatment. It is intended to help field staff working in a variety of locations to decide upon the most appropriate course of action for providing safe water for the communities in which they work. The effectiveness of household water treatment options now and in the future rely to a huge extent on user compliance; it is critical that users are involved in the decision making process, and are aware of the PUR®pose, how to use, maintain and manage their household water options. The brief therefore details relevant hygiene promotion steps for the different treatment options. Introduction The main objective of an intervention to improve household water quality is to ensure that the water consumed will not produce disease - this is especially important for the under 5 age group who experience a large proportion of the morbidity and mortality associated with diarrhoeal disease, and for people with suppressed immune systems such as those suffering from HIV and AIDS. Also critical is that the appearance, taste and colour of the water are acceptable to the consumer. Water and sanitation programmes working to achieve high drinking quality water are starting to focus on reducing contamination throughout the whole water chain, from the source to the point of consumption. This is based on years of comprehensive research which has shown that interventions to improve water quality at the household level, through safer household water handling, storage and treatment, are about twice as effective as those at the source, due to the ease at which water can be contaminated during these stages (Cochrane Review Clasen, Roberts et al 2006). It is not always necessary to include household water treatment in the safe water chain – it is only appropriate when the water source is of a dubious quality. Otherwise, if the source is safe, what is required is to keep the water free from subsequent contamination. This is most simply and cost effectively done by promoting safe water handling and storage and if necessary providing appropriate containers to enable people to do so. However if the quality of water at the source cannot be guaranteed, a treatment process is needed to PUR®ify the water before the drinking. This is referred to as Point – of – use or household water   treatment . There are 7 main options for point of use water treatment in emergencies that are recommended by WHO and will be discussed herein (WHO, 2002). These are: 1.(Sedimentation)2.PUR®®    / waterMaker type sachets (coagulants and disinfectants)3.Ceramic candle style water filters4.Ceramic pot style filters5.Biosand filters6.Boiling7.Solar disinfection (SODIS)8.Chlorination (with tablets or liquid)Table 1 presents a summary of point of use water treatment options. It is intended as a guide for field staff to help them decide which option (s) might be relevant in different settings. For turbid water sedimentation can be used as a pre-treatment method. Boiling is not included in the table as a recommended option - although it is widely practiced and much work has gone into promoting boiling which in the absence of a better treatment works well, it is an expensive and often environmentally damaging option, leaves the water immediately liable to recontamination and contributes to acute respiratory infections and burns. OXFAM Technical Brief – Household water treatment and Storage 1   After treatment, again preventing the PUR®ified water from being re-contaminated is key; the water should be either taken directly from the treatment unit (e.g. a ceramic water filter which has a storage bucket built in) or it should be stored in a safe water container (e.g. after boiling). Box 1 lists the requirements for a good household treatment and storage unit Box 1: Ideal requirements for good household water treatment and storage include: 1.Effective – removes or keeps drinking water free from allpathogens– bacteria, virus’, ova, cysts2.Simple system, easy to use and understand3.Keeps water stored safely without risks of contamination –containers should be covered and able to dispense water ina sanitary manner (e.g. with tap)4.The lid of the water container can be removed so that thecontainer can be cleaned periodically, but also tight fittingto discourage users from using the lid as the main methodof extracting water.5.They must be acceptable to the user and consumer, andthe resulting water must appear and taste good6.Hardware systems should be accompanied by adequatetraining on their use, operation and maintenance7.Regular monitoring of point of use water quality andmaintenance of the system8.In the longer term, the system should be affordable andreplacement parts locally available This technical brief summarises the three stages of the safe water chain – from source to consumption – these are: ã Collection and handling ã Storage ã Treatment COLLECTION & HANDLING Safe water collection and handling means preventing contamination of water when it is collected from the source, transferred from one receptacle to another and when it is extracted before drinking, and preventing further or re-contamination of treated water. Much can be done to prevent contamination through the use of safe containers and treatment processes, but without proper hygiene practices in place the benefits of the hardware are negated. This reinforces the need to address water quality as part of a holistic intervention that focuses on creating an enabling environment to practice safe hygiene. Key principles include: ã Ensuring hands are clean before collecting orhandling water and that they not come into direct contact with the water – this is facilitated through pouring rather than scooping, and having a tap structure on the container ã Use of clean cups and mugs for drinking ã Training on the safe water chain ã Regular cleaning of containers ã Children’s activities on the safe water chain OXFAM Technical Brief – Household water treatment and Storage 2  Table 1: Point of use treatment and health promotion options in different settings Scenario Diarrhoea outbreak or high risk? Household Water Hardware Intervention Public Health Promotion Intervention No Safe water collection and storage containers Check chlorine levels Safe collection and storage Centralised water distribution system with chlorine residual (Camp setting)    Yes Check chlorine levels  AND / OR Mass super chlorination of jerry can / storage containers Safe collection and storage Sensitisation on use of chlorine No Safe water collection and storage containers Safe collection and storage Short term: Household water chlorination (with tablets or liquid) If camp setting: Mass super chlorination of jerry can / storage containers Sensitisation and training on use of chlorine <5NTU water from taps or protected source but no chlorine residual (Multiple sources)  Yes Longer term (select one of): Sodis (if in village or camp with corrugated iron roofs and sun) OR Ceramic pot filters (if existing in-country experience) OR Ceramic Candle filters (preferably if spare parts available locally) OR Biosand filters + safe collection and storage containers AND If camp situation, Periodic super chlorination of jerry can / storage containers O&M training + Safe collection and storage (especially Biosand) Sensitisation on use of chlorine  Short term: Safe water collection and storage containers  AND/OR Explore locally available flocculants and coagulants e.g. alum, natural coagulants Safe water collection and storage Correct use and safe disposal of coagulant No Longer term (select one of): Ceramic pots filters (if existing in-country experience) OR Ceramic Candle filters (preferably if spare parts available locally) OR Biosand filters + Safe water collection and storage containers O&M training + Safe collection and storage (especially Biosand) Short term: If available: PUR® / WaterMaker type sachets If not: Sedimentation (with provision of water storage containers if necessary) + household water chlorination (with tablets or liquid) Correct use and safe disposal of coagulant + sensitisation on taste Sensitisation and training on sedimentation practices + use of chlorine >5NTU water from taps or protected source but no chlorine residual (Multiple sources)  Yes Longer term (select one of): Ceramic Pots (if existing in-country experience) OR Ceramic Candle filters (preferably if spare parts available locally) OR Biosand filters + Safe water collection and storage containers AND If camp situation, Periodic super chlorination of jerry can / storage containers O&M training + Safe collection and storage (especially Biosand) Sensitisation on use of chlorine OXFAM Technical Brief – Household water treatment and Storage 3  STORAGE There are many styles of vessel used to transport and store water in different parts of the world. These range from traditional pots or urns made from naturally available materials such as gourds or clay, to metal containers made of steel, copper or aluminium, and increasingly plastic. The different stages of water collection, transportation and storage require often necessitate different properties from the vessel – for example those used for carrying water need to be light, while ceramic jars which keep the water cool might be preferred for storing water. In terms of preventing contamination of water at the household level there are various design criteria that a storage container should include: 1.Durability – long life span2.Water can be withdrawn in a sanitary manner(e.g. via a tap)3.Cover which can be taken off for cleaning, butwhich users do not use as the main way of extracting drinking water4.Easy to carry if being used for water collectionas well5.Presence or accessibility of documentationdescribing how to properly use the container forwater treatment and sanitary storageIdeally people should have separate containers for collection and storage of drinking water and for clothes washing, washing pots and personal hygiene, to reduce cross contamination with drinking water sources. Emergency storage containers In emergencies, water containers for collecting and storing water are required from the start. As per Sphere (2004) Oxfam promotes that ‘each household has at least two clean water collecting containers of 10-20 litres, plus enough clean water storage containers to ensure there is always water in the household’. Wherever possible Oxfam would advocate using locally appropriate storage vessels, however it is recognised that not all of these have properties and characteristics that are preferred or desirable as water storage vessels. Some, such as cooking pots might be better used as transport vessels especially if they are lightweight, have protective lids and are composed of easily cleaned materials (e.g. plastic). Over the years Oxfam has designed and field-tested the Oxfam bucket to meet the criteria of a practical and safe storage unit (see Box 2). The design is now being used by other agencies in their emergency responses. Box 2: OXFAM buckets The OXFAM buckets have been designed for use in emergency situations. There are two models: 1.Bucket without a tap for collecting and storing water.2.Bucket with a tap which is meant for safely dispensingwater and can also be used as a handwashing device. Both have been designed with the following features: a)The lid is tight fitting with a capped spout to discourage usersto remove the whole lid and prevent contamination of the water by their hands. The cap is attached to the lid to prevent it getting lost. The lid can be removed so the bucket can be periodically cleaned. b)Where the walls meet the base, it is curved to prevent dirtand bacteria lodging in the corners and enables better cleaning. c)They are stackable, with a pallet containing 200 buckets(compared to an equivalent 40 20litre jerry cans) d)The bucket is made of tough durable UV treated plastic andshould last many years. e)When full, it is a safe weight to be carried on someone’s heade)The bucket with a tap has a push tap for a hygienic sealSpecifications can be viewed in the logistics catalogue: Code TWCT/1 = 14 litre water container with tap (pallet of 200 units) Code TWCT/2 = 14 litre water container without tap (pallet of 200 units) OXFAM buckets  – one with the tap shown on raised stand and one without tap on the ground, being used in an IDP camp in Pakistan   OXFAM Technical Brief – Household water treatment and Storage 4
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