Water Pollution Sources 1. Point Sources Wastewater that are discharged from known sources at an identifiable point. Point source pollution can be reduced or eliminated through proper wastewater treatment prior to discharge. 2. Non-point Sources
1. Point Sources
Wastewater that are discharged from known sources at an identifiable point. Point source pollution can be reduced or eliminated through proper wastewater treatment prior to discharge.
2. Non-point Sources
Non-point sources are characterized by multiple discharge points (eg. urban & agricultural runoff). Much of the non-point sources pollution occurs during rain storms. Reduction of non-point source pollution generally requires changes in land use practices.
Environmental Engineering BAA3613
algae can obtain carbon from CO2 dissolved in the water. The largest source of CO2 is from the atmosphere.
usually in the form of nitrate and comes from external sources.
phosphorus in lakes originates from external sources and is taken up by algae in the organic form.
This is called …..
Deep, clear, cold nutrient-poor water, with very little aquatic life
Nutrients and sediment begin to accumulate; increasing populations of aquatic life appear
Nutrient rich, relatively shallow, warmer water, with much plant growth and other aquatic organisms; algal blooms occur
Oldest stage of a lake; very shallow; overgrown with emerging rooted plant life
Eutrophication will kill all animals
and plants in the water
(Ramsar Convention 1971)
Areas of marsh, peatland, or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh brackish or salt, including areas of marine water the depth of which at low tide does not exceed 6 meters
Transition zone between terrestrial and aquatic environments
Highland rivers, headwaters
Peat swamp forest
Shallow inshore waters
- carbon fixation and CO2 balance (photosynthesis)
- rainfall & humidity effects (evaporation & evotranspiration)
- ecosystem diversity
- link between terrestrial and aquatic ecosystem
- high species and population diversity
- highly diverse microbiological activity
- wildlife habitat
Hydrological & hydraulic functions
- storm protection
- coastal erosion protection
- water holding capacity (water catchment)
- water supply
Water quality functions
- particulate filteration
- nutrient stripping
- biodegradation of toxic compounds
- heavy metal removal
- wastewater treatment and water quality improvement
1. Free water surface system (FWS)
2. Subsurface flow system (SFS)
1. Biodegradable organic matter removal
Role of wetland vegetation
i. providing support medium for microbial degradation
ii. conveying oxygen for aerobic degradation to occur
2. Solids removal
Settleable solids are removed easily via gravity sedimentation as wetland systems generally have long hydraulic retention time.
Filtering of solids by plant stems
3. Nitrogen removal
ii.uptake by plants
4. Phosphorus removal
i. uptake by plants
iii.adsorption and precipitation onto soil
5. Heavy metal removal
i. precipitation as insoluble metal hydroxides in the aerobic zone of the substratum
ii. uptake into roots, rhizomes and leaves of wetland vegetation.