Water resources and pollutions

Nota:

• subsidence-sinking land DO-Dissolved oxygen is an important parameter to measure when assessing water quality.  BOD-Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms

1. subsidence

   Nota:

   • sinking land

Nota:

• Freshwater availability – 0.024% – Ground water – Lakes – Rivers – Streams

1. WHO : waterborne disease
2. dry climate
3. more consumer
4. Solution
   1. desalination
      1. RO , distillation
   2. conservation
   3. transporting
   4. irrigation
      1. most efficientive for water usage
   5. reseroire
   6. withdraw groundwater
   7. Treatment
      1. Sewage
         1. septic tank - cesspool
            1. rural suburban
         2. wastewater plant
            1. urban
      2. PBC
         1. Primary
            1. physical process
         2. Secondary
            1. biological process
         3. Chlorination
            1. blenching and disinfection
5. Problem
   1. pollution
      1. point
      2. oxygen sag
      3. non-point
         1. run-off chemical
      4. ocean

         Nota:

         • high accumulate on nutrien
      5. Lake

         Nota:

         • stratification problem
      6. Stream

         Nota:

         • found in developing country
      7. underground water

         Nota:

         • most concern for purification
      8. mostly agriculture waste
   2. waste and loss water
   3. over-demanding

Nota:

• • Holds water molecules together – hydrogen bonding • Liquid over a wide temperature range • Changes temperature slowly • Requires large amounts of energy to evaporate • Dissolves a variety of compounds • Filters out UV light from the sun • Adheres to a solid surface – allows capillary action in plants • Expands as it freezes