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Water in Emergencies

Water in Emergencies. Session 4 Water Sources, Treatment & Implications. Water Supply. Adapted form: Davies & Lambert (2002) Engineering in Emergencies, REDR / ITDG. Water supply in emergency contexts may involve some or all of the above stages. Acceptable yield? Demand vs yield

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Water in Emergencies

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  1. Water in Emergencies Session 4 Water Sources, Treatment & Implications W4

  2. Water Supply Adapted form: Davies & Lambert (2002) Engineering in Emergencies, REDR / ITDG • Water supply in emergency contexts may involve some or all of the above stages W4

  3. Acceptable yield? • Demand vs yield • Seasonal yield • Future yield Ease / ability to obtain an acceptable quality? • Management, legal, security, socio-political & cultural constraints? • Management • Land ownership • Security • Cultural & socio-political issues • Impacts of development? • Existing users • Aquifers • Environment Criteria for selection Water source, treatment & supply • Time of set up vs urgency? • Technical • Resource / logistical • Costs? • Capital • O&M • Ease of O&M? • Requirements • Resource / logistical • Availability of trained staff Adapted form: House & Reed (1997) Emergency Water Sources, WEDC W4

  4. Shallow & Medium Depth Groundwater Shallow well, Lao PDR S House / ACF Handpump on shallow borehole, Liberia S House / ACF W4

  5. Springs Piped Supplies Piped supply from motorised borehole, IDP camp, northern Uganda S House / MSF-OCBA Spring being protected, Zaire S House / WEDC W4

  6. Deep Groundwater Surface Water Submersible pump S House / WaterAid Surface water sources supplying refugee camps, Zaire S House / MSF-OCBA W4

  7. Rainwater Roof collected Ground collected Health facility in an IDP camp, northern Uganda S House / MSF-OCBA Birkad underground rainwater collection tank, northern Kenya S House / AAH-US W4

  8. Implications of selection of Water Source and Supply W4

  9. Scenarios • Spring located above an IDP camp, used by the local community, sited on a private landowners land • Shallow wells developed in a wooded area outside an IDP camp for people displaced by a conflict • Water is being tankered from one part of a city which is under control of one armed group and has to pass through the area of another armed group before reaching its point of supply to a group of displaced people • Water is being piped from a seasonal stream being fed from a spring in a mountainous area following a major earthquake, aftershocks are still being felt • 100,000 displaced persons due to conflict arrive in a semi-arid area and new boreholes are drilled to supply the camps W4

  10. Implications of Selection of Source & Supply Exercise - Consider the particular scenario provided to you and consider the following: • What are the risks / potential negative implications apparent in the scenario and to what or whom? • How could you reduce the risk? W4

  11. Water Treatment • Most common water treatment = chlorination • Chlorination works most effectively with low turbidity of 1 NTU (or max 20 NTU) • Guidelines for chlorination given for pH<8, turbidity <5 NTU, temperature approx 20oC, 30 min retention time • If pH higher, temp lower or turbidity higher then adjust processes W4

  12. Pre-Treatment Pre-treatment: • Roughing filtration • Coagulation, flocculation & sedimentation • Rapid sand filtration Other treatment: • Slow sand filters - but also need pre-treatment to reduce turbidity • Water treatment kits - various methods W4

  13. Bulk Water Treatment Safety needed with chemicals… Coagulation & flocculation Ethiopia S House / WEDC Zaire (DRC) S House / WEDC Field ‘Jar test’ Pakistan S House / OXFAM-GB W4

  14. Chlorination Practical handout on chlorination provided W4

  15. Household water treatment • Candle filters • Ceramic pot filters • Biosand household filters • Chlorination • Boiling • Sodis – using UV light & plastic bottles • Local natural coagulants Moringa Oliefera Waterlines Cambodia H Jones / WEDC W4

  16. Candle filter units OXFAM-GB W4

  17. Bulk vs Household Treatment W4

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