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Investigate interactions between humans and micro-organisms

Investigate interactions between humans and micro-organisms

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Investigate interactions between humans and micro-organisms

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    1. Investigate interactions between humans and micro-organisms Science A.S. 1.11 2011 Introduce topic Brain storm (what are they, relate to pet MRS GREN) Microbes include fungi, bacteria, virus microscopic organismsIntroduce topic Brain storm (what are they, relate to pet MRS GREN) Microbes include fungi, bacteria, virus microscopic organisms

    2. Micro-organisms Students encouraged to discuss size of the microorganisms and how something so small might cause illness Can only see them when there are millions growing together -colony Students encouraged to discuss size of the microorganisms and how something so small might cause illness Can only see them when there are millions growing together -colony

    3. Definitions Parasites feed on living hosts Saprophytes feed on dead matter Decomposers breakdown dead matter and recycle the nutrients Pathogens are disease causing organisms (most parasites are also pathogens) Extra cellular digestion is the process by which bacteria and fungi feed Binary fission is the process by which bacteria reproduce Parasites feed on living, saprophytes feed on dead (decomposers) pathogen disease causing Parasites feed on living, saprophytes feed on dead (decomposers) pathogen disease causing

    4. Bacteria Structure Flagella movement Cell wall shape Cell membrane lets things in and out of the cell Extra cellular digestion Capsule protection (shiny round colonies) Parasites, pahogens, decomposers but hey are all consumers they cant make their own foodDiscuss parts and functions Copy and label diagram on page 104 new directionsParasites, pahogens, decomposers but hey are all consumers they cant make their own foodDiscuss parts and functions Copy and label diagram on page 104 new directions

    5. Bacterial Life Processes Reproduction Binary fission Nutrition Parasites, saprophytes Extra cellular digestion Excretion Toxins (cause human disease) Respiration Aerobic / anaerobic Reproduce by binary fission 2 daughter cells Draw process pg 104 Extra cellular digestion, secrete and reabsorb As they respire they produce energy and waste (toxin) EXPT how to innoculate and incubate and agar plate Reproduce by binary fission 2 daughter cells Draw process pg 104 Extra cellular digestion, secrete and reabsorb As they respire they produce energy and waste (toxin) EXPT how to innoculate and incubate and agar plate

    6. Bacterial Growth Humans get sick because bacteria numbers increse quickly and their waste products reach toxic levels COLONIESHumans get sick because bacteria numbers increse quickly and their waste products reach toxic levels COLONIES

    7. Boils, gangrene, madura foot, necrotising fascitis Everyone has bacteria, sometimes they are opportunistic infectionsEveryone has bacteria, sometimes they are opportunistic infections

    8. Test yourself Discuss why a person has no side effects in the first stages of bacterial infection, but after 24 hours feel unwell. Refer to bacterial life processes in your answer. Growth graph Small numbers = no side effect Fast reproduction Large numbers, respiration, waste (toxin)

    9. Fungi Structure Hyphae threads Absorb nutrients and water Extra cellular digestion Mycelium mat of hyphae (furry edge colonies) Fruiting body (cap/sporangium) spore production and release New directions pg 106 draw and label typical structure New directions pg 106 draw and label typical structure

    10. Fungi Life Processes Respiration Tend to be aerobic so cause skin diseases Nutrition Saprophyte or parasite Extra cellular digestion Reproduction Spores Antibiotics defence Largest organism Describe drawing fungi are saprophytes or parasites depending what they feed on. Most fungi are aerobes so tend to produce skin infections Many fungi produce chemicals which can slow bacterial growth or even kill them =Ab like penicillin Read paragraph on pg 106 answer Q2 Inoculate (transfer microbes to) and incubate (warm) AGAR plate draw picture on boardDescribe drawing fungi are saprophytes or parasites depending what they feed on. Most fungi are aerobes so tend to produce skin infections Many fungi produce chemicals which can slow bacterial growth or even kill them =Ab like penicillin Read paragraph on pg 106 answer Q2 Inoculate (transfer microbes to) and incubate (warm) AGAR plate draw picture on board

    11. Thrush, Athletes foot, Ringworm Fungi Fungi, bread, beer, mushrooms and bad sideFungi, bread, beer, mushrooms and bad side

    12. Viral Structure Protein coat Attaching to host Nuclear material DNA or RNA Package of genetic material HIV picturedHIV pictured

    13. Viral Life Processes Alive or not? MRS GREN Reproduction Hijacks living cell Injects genetic material Host copies and packages Causes cell lysis (destroys host cell function and therefore leads to disease) Think mrs gren Either Dna or Rna, in protein coat Describe process of bacteriophage replicating in e coli, bind surface, inject material, incorporate into host genome, lots copies made, packed in cell cytoplasm, cell lysis, kills host Smallpox estimated to have killed 0.5 billion, in 1796 Jenner saw cowpox prevented smallpox and vaccinated himself in 1967 it killed 2m by 1980 WHO declared world free, 1996 monkey pox (mutation)kills 500 in africaThink mrs gren Either Dna or Rna, in protein coat Describe process of bacteriophage replicating in e coli, bind surface, inject material, incorporate into host genome, lots copies made, packed in cell cytoplasm, cell lysis, kills host Smallpox estimated to have killed 0.5 billion, in 1796 Jenner saw cowpox prevented smallpox and vaccinated himself in 1967 it killed 2m by 1980 WHO declared world free, 1996 monkey pox (mutation)kills 500 in africa

    14. Smallpox, Mumps, Measles - Virus The bad side of virus, discuss inoculation, and antibiotic useThe bad side of virus, discuss inoculation, and antibiotic use

    15. Compare and Contrast Virus Needs living host to reproduce Doesnt feed Doesnt move Doesnt respire Non- living? Bacteria Reproduces via binary fission Saprophyte/ parasite Moves with Flagella/ pilli Aerobic or anaerobic Living Draw a comparison table of all 3 EXPT agar plate and antisepticsDraw a comparison table of all 3 EXPT agar plate and antiseptics

    16. Test yourself Explain why a person with a viral infection will not show any effects from toxins. In your answer describe how toxins are produced. Virus non living No respiration No waste = no toxins

    17. Defense against Microbes Human Prevention The skin and mucus secretions act as a barrier preventing infection Passive immunity W.B.C.s called phagocytes engulf and digest antigens Active immunity W.B.C.s called lymphocytes produce antibodies against the antigen Passive born with this defence, body recognises foreign particles and attacks them result swelling, heat, dead phagocytes(killed by toxins) = pus Active immunity is aquired during your life. when you encounter a antigen antibodies are produced which remember the foreign substance next time you encounter it they are activated and send a quich response to fight it off. This is why we dont catch things like measles more than once. It is also the basis of vaccination (attenuated) antigen Case study from book? New directions pg 121 Q5 AIDSPassive born with this defence, body recognises foreign particles and attacks them result swelling, heat, dead phagocytes(killed by toxins) = pus Active immunity is aquired during your life. when you encounter a antigen antibodies are produced which remember the foreign substance next time you encounter it they are activated and send a quich response to fight it off. This is why we dont catch things like measles more than once. It is also the basis of vaccination (attenuated) antigen Case study from book? New directions pg 121 Q5 AIDS

    18. Defense against Microbes Chemical Disinfectants chemicals which kill or inhibit the growth of microbes Antibiotics naturally occurring chemicals (fungi) which kill or inhibit bacterial growth but have no affect on virus Antiseptic term for anything which reduces or controls infection View agar plate antiseptic EXPT Talk toxin build up againView agar plate antiseptic EXPT Talk toxin build up again

    19. Drug Resistant Micro-organisms Microbes with greater fitness may be capable of surviving drug treatment. Resistant traits are inherited by offspring. Population becomes drug resistant. Individual organisms vary in their sensitivity to the drug used and some with greater fitness may be capable of surviving drug treatment. Drug resistant traits are accordingly inherited by subsequent offspring, resulting in a population that is more drug resistant. ALWAYS TAKE THE FULL DOSEIndividual organisms vary in their sensitivity to the drug used and some with greater fitness may be capable of surviving drug treatment. Drug resistant traits are accordingly inherited by subsequent offspring, resulting in a population that is more drug resistant. ALWAYS TAKE THE FULL DOSE

    20. Pandemic An infectious disease that is spreading through human populations across the world. In 1918 Spanish Flu killed 50-100 million people. This was 3% of the world's population. 1 in 3 people were infected. HIV is a pandemicHIV is a pandemic

    21. Swine Flu The rapid reproduction of micro-organisms means they can evolve very quickly. Animal infections can mutate and infect humans who are in close contact. Infections can become airborne. The rapid reproduction of micro-organisms means they can evolve very quickly. Immune to Ab. Animal infections can mutate and infect humans who are in close contact. Infections can become airborneThe rapid reproduction of micro-organisms means they can evolve very quickly. Immune to Ab. Animal infections can mutate and infect humans who are in close contact. Infections can become airborne

    22. Government Pandemic Control Plan for it Engage with all relevant agencies Keep it out Border Management Stamp it out Cluster Control Manage it Public Health Measures, Antivirals Recover from it Begins when the first cases are seen Hospitals, government, schools, personal household plans Agressively contain and quarantine out reach clinics set up to cope with demand, drug stockpiles, press awareness campaignsHospitals, government, schools, personal household plans Agressively contain and quarantine out reach clinics set up to cope with demand, drug stockpiles, press awareness campaigns

    23. Personal Preparedness Who do you need to help? Who could help you? Do you have an emergency supplies kit? Do you have a list of key contact information? Doctors People who live near you Family Complete preparedness plan and kitComplete preparedness plan and kit

    24. Personal Hygiene Wash and dry hands regularly. Cover coughs and sneezes. Put tissues into the bin . Stay away from sick people. before - cooking and eating after - coughing, sneezing, blowing noses, using the toilet or looking after sick people. 1m distance from the sick before - cooking and eating after - coughing, sneezing, blowing noses, using the toilet or looking after sick people. 1m distance from the sick

    25. Factors Affecting Microbial growth Microbes have adapted to live in almost every environment In order to grow microbes need: Food Moisture Warmth Time Oxygen? Students work out what the factors are based on previous learning about food hygiene then look at each factor in next 4 slides, relate adaptation to environment and Rotoroa Draw up table heading factors, what the factors influence, reasons links kids fill it in as we proceed through the next slidesStudents work out what the factors are based on previous learning about food hygiene then look at each factor in next 4 slides, relate adaptation to environment and Rotoroa Draw up table heading factors, what the factors influence, reasons links kids fill it in as we proceed through the next slides

    26. Factors Affecting Microbial growth Moisture Microbes need moisture to grow. Salt lowers the freezing point of water providing extremophiles the moisture they need to survive at low temperatures. Influence growth as Life depends on water Reasons nutrients dissolve in water and become available to the cell, water makes up most of the cell No water equals dormant or spores all microbes need water to grow Influence growth as Life depends on water Reasons nutrients dissolve in water and become available to the cell, water makes up most of the cell No water equals dormant or spores all microbes need water to grow

    27. Factors Affecting Microbial growth Temperature Bacteria grow well between 4C - 63C. This is called the danger zone. Extremophiles can survive in: the Antarctic at -56C(as long as water and food are present) deep sea vents at 400C. Influence growth rate, each microbe has an optimum growth range Reason enzymes that control cell reactions work best at the optimum range Links Making cheese, wine, bread, incubatng diseaseInfluence growth rate, each microbe has an optimum growth range Reason enzymes that control cell reactions work best at the optimum range Links Making cheese, wine, bread, incubatng disease

    28. Factors Affecting Microbial growth Nutrition photosynthesis accounts for 99% of the energy that powers life Extremophiles can be found in: aphotic (non-light) environments e.g. deep sea trenches. They use thermal and chemical energy sources. anoxic (non-oxygen) environments e.g. swamps. Methanogens combine carbon dioxide (CO2) and hydrogen (H2) to produce organic matter, and methane. Life mostly depends on the sun Inluence growth as nutrients mean more growth Reasons fod vitamins mnerals needed for energy, cellular growth and reproduction Links biotechnology, wine, disease etc as nutrients converted to waste products OXYGEN required by fungi and aerobic bacteria, oxygen releases energy from food, growth slows if oxygen limited Anaerobic bacteria are limited or killed by oxygen (Aerobic/Anaerobic respiration demo?) Life mostly depends on the sun Inluence growth as nutrients mean more growth Reasons fod vitamins mnerals needed for energy, cellular growth and reproduction Links biotechnology, wine, disease etc as nutrients converted to waste products OXYGEN required by fungi and aerobic bacteria, oxygen releases energy from food, growth slows if oxygen limited Anaerobic bacteria are limited or killed by oxygen (Aerobic/Anaerobic respiration demo?)

    29. Factors Affecting Microbial growth Oxygen Aerobic bacteria use oxygen for respiration. Anaerobic bacteria can respire without using oxygen. Both reactions produce energy. What is it used for? FERMENTATION EXPT make ginger beer Anaerobes might use Hydrogen sulphide Our muscles can do this to produce lactic acid = cramp YEAST FUNGI REPRODUCE BY BINARY AND IS ANAEROBIC FERMENTATION EXPT make ginger beer Anaerobes might use Hydrogen sulphide Our muscles can do this to produce lactic acid = cramp YEAST FUNGI REPRODUCE BY BINARY AND IS ANAEROBIC

    30. Factors Affecting Microbial growth pH Most bacteria like neutral pH microbes have been shown to occupy nearly every range of pH. E.g. acid mine drainage at pH 0.5 and soda lakes at pH 11. Some bacteria can thrive in extremes Influence enzymes denature if not in correct pH Reasons enzymes need correct ph, organism dies if enzymes dont work Links biotechnology wine, beer, yoghurt need right pH to get good productSome bacteria can thrive in extremes Influence enzymes denature if not in correct pH Reasons enzymes need correct ph, organism dies if enzymes dont work Links biotechnology wine, beer, yoghurt need right pH to get good product

    31. Factors Affecting Microbial growth Time Microbes need time to grow. In ideal conditions bacteria can multiply every 20 mins. After two hours at room temperature food could have enough bacteria to cause food poisoning. Exponential growth in ideal conditions, new ideas pg 105 q8 Provide GRAPH PAPER Experiment to grow microbes on agar, finger print, wash hand, lick finger, control Handout for plating up Soil and antiseptic dots?Exponential growth in ideal conditions, new ideas pg 105 q8 Provide GRAPH PAPER Experiment to grow microbes on agar, finger print, wash hand, lick finger, control Handout for plating up Soil and antiseptic dots?

    32. Micro-organisms are helpful Food production Bread Alcohol Cheese Yoghurt Nutrient recycling Composting Medicine production Antibiotics Insulin Discuss each of the beneficial ways depicted with questioning to identify understanding and prior knowledge So microbes are good? Expt make ginger beer fermentation reaction co2 and alcohol production relate to bread, why not alcoholic Expt make yoghurtDiscuss each of the beneficial ways depicted with questioning to identify understanding and prior knowledge So microbes are good? Expt make ginger beer fermentation reaction co2 and alcohol production relate to bread, why not alcoholic Expt make yoghurt

    33. Microbial food production Cheese Alcohol Yoghurt Mushrooms Bread Expt make ginger beer, yoghurt cheese?Expt make ginger beer, yoghurt cheese?

    34. Sewage treatment by microbes

    35. Microbes clean our water Stores rainwater Metal grids keep out weeds and debris Chemicals make particles stick together Stands for 3hr to let large particles sink (digested by microbes) Gravel and sand removes most particles Kills microbes

    36. Composting and Nutrient Recycling As living organic species die, decomposing microbes recycle them. Nitrogen cycle Carbon cycle Composting Green Brown Air water Turn it monthly and it will be ready in 3-4 months otherwise 1 year WHY DO THEY RECYCLE FOR US?Turn it monthly and it will be ready in 3-4 months otherwise 1 year WHY DO THEY RECYCLE FOR US?

    37. Nitrogen Recycling How do microbes aid us in recycling Plants and animals cannot get nitrogen to make their proteins from the air - although it is 80% nitrogen. Nitrogen is not reactive. Nitrogen is essential for plant growth. Factors such as soil moisture, aeration, temperature, pH, and microbial breakdown of soil organic matter influence the availability of nitrogen to plants. The availability of nitrogen increases through application of inorganic or organic fertilizers to the soil. Nitrogen availability also increases through bacterial fixation of gaseous nitrogen (N2) to ammonium (NH4) compounds which can be absorbed by plants. Nitrification Two forms of nitrogen available to plants are nitrate (NO3-) and ammonium (NH4+) nitrogen. Roots can absorb both of these forms. Ammonium-nitrogen is often converted to nitrate-nitrogen by microorganisms before absorption through a process called nitrification. Modification of NH4+ to NO3- depends on the temperature of the soil; transformation proceeds more quickly under warmer soil temperatures (above 50 F). How do microbes aid us in recycling Plants and animals cannot get nitrogen to make their proteins from the air - although it is 80% nitrogen. Nitrogen is not reactive. Nitrogen is essential for plant growth. Factors such as soil moisture, aeration, temperature, pH, and microbial breakdown of soil organic matter influence the availability of nitrogen to plants. The availability of nitrogen increases through application of inorganic or organic fertilizers to the soil. Nitrogen availability also increases through bacterial fixation of gaseous nitrogen (N2) to ammonium (NH4) compounds which can be absorbed by plants. Nitrification Two forms of nitrogen available to plants are nitrate (NO3-) and ammonium (NH4+) nitrogen. Roots can absorb both of these forms. Ammonium-nitrogen is often converted to nitrate-nitrogen by microorganisms before absorption through a process called nitrification. Modification of NH4+ to NO3- depends on the temperature of the soil; transformation proceeds more quickly under warmer soil temperatures (above 50 F).

    38. Bacteria in root nodules of legumes (beans and peas) convert Nitrogen to Nitrate

    39. Carbon Recycling Discuss and question students on carbon cycle new directions 109 q3 How is mans activity affecting the process, logging, fossil fuels, cars What can we do to reduce the effect Greenhouse gases, global warming New dir 107 q3Discuss and question students on carbon cycle new directions 109 q3 How is mans activity affecting the process, logging, fossil fuels, cars What can we do to reduce the effect Greenhouse gases, global warming New dir 107 q3

    40. Micro-organisms are Harmful Micro-organisms will spoil food and cause disease or food poisoning. Symptoms include: nausea Vomiting Diarrhoea abdominal cramping Can be caused by any microbe but virus most common, generally lasts 24-48 hrsCan be caused by any microbe but virus most common, generally lasts 24-48 hrs

    41. Micro-organisms cause disease Discuss black death in Europe PLAGUE, LEPROSY Disease in plants Irish famine 1845 potato blight caused by fungi, feed on plant grow through it, move by spore release tobacco mosaic virus (first virus discovered 30s)Discuss black death in Europe PLAGUE, LEPROSY Disease in plants Irish famine 1845 potato blight caused by fungi, feed on plant grow through it, move by spore release tobacco mosaic virus (first virus discovered 30s)

    43. N.Z. Food Poisoning 119,000 360 19,000 400 22 2 55.1 www.beehive.govt.nz/Print/PrintDocument.aspx?DocumentID=9227 In the next 7 slides Students decide how the numbers relate to food poisoningIn the next 7 slides Students decide how the numbers relate to food poisoning

    51. Kitchen Hygiene Always wash hands thoroughly before starting to cook. Wash all fruits and vegetables. Use separate chopping boards for fruit/vegetables and meat. Store cooked and raw food separately and always wash your hands after handling raw meat or fish. Always check the sell-by dates on ingredients. food hygiene Discuss food hygiene and link to interactive programme 15 qs alien quizDiscuss food hygiene and link to interactive programme 15 qs alien quiz

    52. Test Yourself Using named examples explain how micro-organisms can be both helpful and harmful to humans. You should consider life processes and waste products in your answer. Harmful bacteria disease nutrition and respiration (anaerobic or anaerobic) excretion toxin production Helpful fungi make alcohol and bread, anaerobic fermantation(respiration) excrete alcohol, fungi make Ab as defence against bacteria - bacteria decompose (saprophytes) sewage treatment,Harmful bacteria disease nutrition and respiration (anaerobic or anaerobic) excretion toxin production Helpful fungi make alcohol and bread, anaerobic fermantation(respiration) excrete alcohol, fungi make Ab as defence against bacteria - bacteria decompose (saprophytes) sewage treatment,

    53. Food Preservation- to prolong the storage of food by preventing microbial growth/ reproduction Temperature Cooking food at 75C - 80C kills bacteria within two minutes Pasturisation 60C Canning Cooking kills all microbes Pasturisation doesnt affect the taste of milk Canned food is heatedCooking kills all microbes Pasturisation doesnt affect the taste of milk Canned food is heated

    54. Food Preservation Moisture If you remove water from food, bacteria will not grow. Jam high sugar, dehydrated spaceman food, mummiesJam high sugar, dehydrated spaceman food, mummies

    55. Food Preservation Freezing/Refrigerating Food in the refrigerator (4C) is safe for only short periods of time. Remove Oxygen Vacuum pack Foil Toxins can still build up Mammoth 10000 yr old so well preserve still got fur and eyes potential to bring back from extinction transplans sperm/ egg dna into elephant Log fell in anaerobic swamp, lack of oxygen then minerals leech in New directions pg 111 q1,23,4Toxins can still build up Mammoth 10000 yr old so well preserve still got fur and eyes potential to bring back from extinction transplans sperm/ egg dna into elephant Log fell in anaerobic swamp, lack of oxygen then minerals leech in New directions pg 111 q1,23,4

    56. Disinfectant- Chemical that destroys or inhibits growth of microbes Antibiotic naturally produced substance which kills or inhibits bacterial growth but has no effect on virusDisinfectant- Chemical that destroys or inhibits growth of microbes Antibiotic naturally produced substance which kills or inhibits bacterial growth but has no effect on virus

    57. Sewage Treatment

    58. Sewage Treatment Where does your sewage go? Whenever you flush the toilet or open the drain on your sink, you are releasing sewage. Sewage is mainly water along with a small amount of impurities which may be suspended solids or dissolved substances. Your sewage will go through the sewage system to a sewage treatment plant. At the sewage treatment plant the organic material in the sewage has to be decomposed so that the sewage has little to no effect on the oxygen demand in the waters into which the sewage is released. Screening: the water flows through a grate to remove large solid objects from the water. The debris that gets caught on the grate is cleaned off at regular intervals. 3. Grit removal: The raw sewage contains sand and gravel. This sand and gravel has to be removed from the wastewater. The wastewater is pumped into aerated grit tanks. In the aerated grit tanks, the sand and gravel are removed. Once the sand and gravel are removed, the sand and gravel are washed and then hauled to the sanitary landfill. The liquid left in the grit tanks is sent for primary clarification. 4. Primary Clarification: This consists of water sitting undisturbed in settling tanks for approximately 3 hours. During this time, larger organic particles settle to the bottom of the tanks. This forms a dense sludge at the bottom of the tanks. This sludge is sent to the Anaerobic Digester (step 7). 5. Aeration: Oxygen and aerobic bacteria go to work here. With an abundant supply of oxygen the bacteria or microorganisms feed on the organic nutrients in the sewage and thus "use up" the sewage. The bacteria and microorganisms are said to be "digesting the sewage". After about three hours, the mixture from these aeration tanks is sent for clarification. 6. Final Clarification: The water mixture sits in these clarifying tanks for about four hours. The sludge that forms at the bottom of the tanks is collected underwater and pumped back into the aeration tanks to maintain the balance that is needed in the aeration tanks. This sludge is controlled in order to balance the digestion of the sewage. Any excess sludge is put into the primary clarification tanks to be reprocessed. After the four hours are up in the final clarification tanks, the wastewater is released into Yorkton Creek. 7. Sludge Digestion: The sludge collected in any of the tanks and not used in the control of the aeration environment is pumped to the primary Anaerobic Digester. Here the sludge is digested in a hot environment containing no oxygen. This digestion requires about 20 days. After the 20 days the sludge goes to the secondary digester where the sludge needs to be thickened. Any excess liquid that forms on the top is returned to the plant while the thickened sludge is put in storage lagoons. When the sludge is thick enough, it is spread on farm land nearby. Where does your sewage go? Whenever you flush the toilet or open the drain on your sink, you are releasing sewage. Sewage is mainly water along with a small amount of impurities which may be suspended solids or dissolved substances. Your sewage will go through the sewage system to a sewage treatment plant. At the sewage treatment plant the organic material in the sewage has to be decomposed so that the sewage has little to no effect on the oxygen demand in the waters into which the sewage is released. Screening: the water flows through a grate to remove large solid objects from the water. The debris that gets caught on the grate is cleaned off at regular intervals. 3. Grit removal: The raw sewage contains sand and gravel. This sand and gravel has to be removed from the wastewater. The wastewater is pumped into aerated grit tanks. In the aerated grit tanks, the sand and gravel are removed. Once the sand and gravel are removed, the sand and gravel are washed and then hauled to the sanitary landfill. The liquid left in the grit tanks is sent for primary clarification. 4. Primary Clarification: This consists of water sitting undisturbed in settling tanks for approximately 3 hours. During this time, larger organic particles settle to the bottom of the tanks. This forms a dense sludge at the bottom of the tanks. This sludge is sent to the Anaerobic Digester (step 7). 5. Aeration: Oxygen and aerobic bacteria go to work here. With an abundant supply of oxygen the bacteria or microorganisms feed on the organic nutrients in the sewage and thus "use up" the sewage. The bacteria and microorganisms are said to be "digesting the sewage". After about three hours, the mixture from these aeration tanks is sent for clarification. 6. Final Clarification: The water mixture sits in these clarifying tanks for about four hours. The sludge that forms at the bottom of the tanks is collected underwater and pumped back into the aeration tanks to maintain the balance that is needed in the aeration tanks. This sludge is controlled in order to balance the digestion of the sewage. Any excess sludge is put into the primary clarification tanks to be reprocessed. After the four hours are up in the final clarification tanks, the wastewater is released into Yorkton Creek. 7. Sludge Digestion: The sludge collected in any of the tanks and not used in the control of the aeration environment is pumped to the primary Anaerobic Digester. Here the sludge is digested in a hot environment containing no oxygen. This digestion requires about 20 days. After the 20 days the sludge goes to the secondary digester where the sludge needs to be thickened. Any excess liquid that forms on the top is returned to the plant while the thickened sludge is put in storage lagoons. When the sludge is thick enough, it is spread on farm land nearby.

    59. Hospital Hygiene Newspaper headlines mostly linked to poor hygiene Create poster to raise awareness of correct handwashing what is the audience doctor, family, student, kidsNewspaper headlines mostly linked to poor hygiene Create poster to raise awareness of correct handwashing what is the audience doctor, family, student, kids

    64. Nitrogen Cycle Sapprophyte Vs parasite recap How do microbes aid us in recycling NO3 Nitrate No2 Nitrite N2 fixed NO3 by lightning, bacteria(anaerobic), industry Discuss prior to book workSapprophyte Vs parasite recap How do microbes aid us in recycling NO3 Nitrate No2 Nitrite N2 fixed NO3 by lightning, bacteria(anaerobic), industry Discuss prior to book work

    65. Micro-organisms are Good Yeast is a micro-organism, essential to make bread Microbes are good for usMicrobes are good for us