Characteristics Flashcards
Water Quality
Is the water “fit for purpose”. It the water maintained to a certain purpose.
Water Quality Management
Controlling the impact of human activity to meet water quality standards. (3.6 million people die annually from water related illnesses)
Evaporation
External heat allows transition from liquid to vapour. This can also occur as transpiration from vegetation.
Condensation
As air rises and cools, water vapour condenses around small particles to form clouds.
Circulation
Transmits moisture horizontally as wind or advective currents
Precipitation
Return the water to the Earth surface in the form of rain, snow or hail.
Infiltration
Entry of precipitation to the soil, then on downwards. This is governed by permeability and saturation.
Transportation
Surface runoff moves water along defined channels to the sea.
Percolation
Infiltrated water moves down through the aerated zone to join groundwater seeping slowly towards the sea.
What human influences are there one the water cycle? Name 8.
- Urban and Highway Development
- Agricultural Drainage
- Natural Vegetation
- Water abstraction
- Increasing population
- Increasing affluence
- Rapid urbanisation
- Climate change
Water Footprint
The total volume of fresh water used to make a product (27 litres to make 1 cup of tea)
What are the three types of water?
- Blue - fresh water lakes, rivers and aquifers
- Green - rainfall stored in the soil
- Grey - polluted water
What are the physical characteristics of water? Name 9
- Density (maximum at 4 degrees), causes burst pipes, thermal stratification
- Temperature affects the solubility of oxygen and the speed of chemical reactions
- Taste and odour indicates dissolved impurities
- Colour indicates material in solution or suspension.
- Solids in solution or suspension and could be organic or inorganic
- Turbidity (cloudiness) due to colloidal solids
- Electric conductivity depends of dissolved salts
- Salinity is the concentration of ionic constitutients
- Radioactivity beta and gamma activity
Electric Conductivity Equation
Conductivity = Constant x Total Dissolved Solids
What are the chemical characteristics of water? Name 12
- pH
- Alkalinity
- Acidity
- Hardness
- Dissolved Oxygen
- Oxygen Demand
- Biochemical Oxygen Demand
- Chemical Oxygen Demand
- Total Organic Carbon
- Nitrogen
- Chloride
- Trace Organics
Chemical Characteristics: pH, alkalinity and acidity
This is the strength of acidity or baseness (concentration of hydrogen ions present).
Alkalinity is the presence of bicarbonate, carbonate or hydroxide ions (mostly natural from chalk or limestone)
Acidity is the presence of carbonic acid
Chemical Characteristics: Hardness
High mineral content which produces scale mainly due to calcium and magnesium.
Chemical Characteristics: Dissolved oxygen
Amount of oxygen dissolved in the water - very important for biological life, decreases with temperature, decreases with organic matter and is seasonal
Chemical Characteristics: Oxygen Demand
Amount of organic waste present - indicated as organic compounds are unstable and will oxidise to produce more stable products.
Chemical Characteristics: Biochemical oxygen demands
Quantity of dissolved oxygen consumed per unit volume by microorganisms whilst breaking down organic matter during a specified time at a specified temperature.
Chemical Characteristics: Chemical oxygen demand
Quantity of oxygen demand during chemical oxidation. Tested by boiling potassium dichromate and concentrated sulphuric acid. Usually COD>BOD.
Chemical Characteristics: Total organic carbon
Determine organic matter by measuring a sample’s ability to absorb UV light
Chemical Characteristics: Nitrogen
Is needed for biological reactions. During the process of nitrification it exists as:
- Organic nitrogen
- Ammonia nitrogen
- Nitrite nitrogen
- Nitrate nitrogen
Chemical Characteristics: Chloride
Brackish taste in water - present in urine
Chemical Characteristics: Trace organics
Industrial effluent - 600 organic compounds have been found in raw water due to human activity including benzene, chlorophenols, oestrogens, pesticides