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MICROBES F 2

MICROBES F 2. SL and HL. Consequences of releasing nitrate fertilizer into water bodies. Most of nitrate ions can be washed into the lake and river and cause pollution. Sewage----------------Water Pollution. FROM HOUSE- Human feces , Kitchen residue, Detergents.

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MICROBES F 2

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  1. MICROBESF 2 SL and HL

  2. Consequences of releasing nitrate fertilizer into water bodies • Most of nitrate ions can be washed into the lake and river and cause pollution.

  3. Sewage----------------Water Pollution FROM HOUSE- Humanfeces, Kitchen residue, Detergents. INDUSTRY- waste----- – strongly acidic/alkaline chemicals Toxic metal ions- Cu, Zn and Cr. ANIMAL FARM Leakage of animal slurries from animal waste. FARM FIELDS Run off water--- contain artificial fertilizers (nitrate)

  4. If water is polluted • Rapid changes in the physical factors of the environment

  5. The main components of sewage and their effects in a fast flowing river.

  6. Water pollution • BOD-biochemical oxygen demand. • Sample of water –at 20 oC for 5 days. Presence of Polluting OM Increased activity of Bacteria Decomposition of OM Resulting High demand of dissolved Oxygen The BOD measurement –indication of the level of organic pollution

  7. Changes in water quality after the introduction of raw sewage in fast flowing river

  8. Intial stages Sewage enters the the river Immediate decomposition of OM (aerobic bacteria) Demand for dissolved O2 is high Resulting Rapid decrease in O2 concentration.

  9. Oxygen Sag occurs-when the rate of consumption is greater than the rate at which O2 is produced Decomposition of OM-Number of aerobic bacteria decreases No. of the Protozoans increases

  10. Eutrophication • Artificial enrichment of nutrients in a river or lake. • Algal bloom- Excess nutrients in the water encourages rapid growth of algae and blue-green bacteria resulting Algal bloom.

  11. Algal bloom- • Number of algae increases when- Suspended solids settles Water becomes clear Light penetrate Photosynthesis takes place Dissolved Oxygen level rises NO3 and PO4 ions absorbed

  12. Algae die aerobic bacteria Oxygen level falls very low Sudden death of masses of fish If water is anaerobic H2S and CH4 is produced Blue-green bacteria -------toxins------cause the death of fish and other animals. Recovery of river Oxygenation of water improves Dilution of the sewage and nutrients

  13. Role of Saprotrophic bacteria in the treatment of sewage water • In sewage treatment plant- Uses natural decay processes conditions for micro organisms Decomposition of OM (aerobic ) Final product are CO2 released in atmosphere NO3 and PO4 –dissolved in water Sediment and sludge is decomposed anaerobically to produce CH4

  14. Sewage purification

  15. Sewage treatment 1. Screening of water ------allowing water into a grit settlement tank. Grit—small stones and sand 2. Water is passed thru trickling filter - degraded stones, grit and clinker • Bacteria, fungi and protozoa degrade OM as the waste water trickles thru the bed and • These are consumed by predatory protozoa and insect larvae.

  16. An alternative method • Use of Reed bed • The Common Reed ( Phragmitesaustralis.) has the ability to transfer oxygen from its leaves, down through its stem, and out via its root system. • As a result of this action, a very high population of micro-organisms occurs • Able to breakdown any soluble material.

  17. Use of Biomass • Production of methane and ethanol • What is Biomass? • total mass of living material in an area. • Dry mass in Kg per square metre. (Kg/m2)

  18. Fermentation • Sugar by Sacccharomyces --- Yeast • Convert biomass into ethanol ---used as fuel • Eg., GASOHOL Unleaded petrol mixed with ethanol(10-20%) used in modified motor vehicles. Sugar ----sugarcane—tropical countries sugarbeet--- temperate countries

  19. Fermentation by bacteria • Biomass----biogas---CH4 • Mixture of different gases produced as a result of action of anaerobic microorganisms on domestic and agricultural wastes. Methane 50-68% CO2 25-35% traces of H2S , NH3, H2 and N2

  20. Methane from biomass • IntiallyFaeces ferment Aerobic bacteria hydrolyse Carbohydrates, Lipids, Protein Sugars, glycerol and fatty acids and amino acids

  21. Available oxygen is used up acetogenic bacteria converts sugars short chains of Fatty acids especially Ethanoate ions (CH3COO-) and H2 and CO2 this stage is termed as acetogenesis

  22. Final stage-methanogenesis • by methanogenic bacteria • Are obligate anaerobes (only active in the absence of oxygen) • Members of Archaebacteria Ethanoate and other acids methane CH3COOH CH4+ CO2

  23. Biogas production • 30-40 degrees Celsius • Closed tank-digester • China, India, Nepal • Developed countries-dispose large quantity of animal waste from intensive farming.

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