MICRO 3050- EXAM 4 QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED

MICRO 3050- EXAM 4 QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED Leave the first rating Practice questions for this set Terms in this set (142) typhoid fever Salmonella typhi, was a major public health threat before drinking water treatment cholera Vibrio cholera, seven major pandemics since 1817, often occurs in areas with inadequate or no sewage treatment protozoan infections Giardia, Crytosporidium, Entamoeba- may be present in surface waters and may survive water treatment facilities as cysts; these can survive through filtration cuyahoga river it was so polluted that it caught fire many times lake hartwell fish caught from this lake cannot be eaten because PCB's are present dead zone in the gulf of mexico nitrogen and phosphorous limit plant growth; oxygen is very low = no life Mediterranean and tourism bodies of water contain sewage even in developed countries point sources domestic (houses) and industrial (plants, etc.) non-point sources parking lots (oil leakage), feed lots, agricultural fields, golf courses and yards how do graveyards affect water pollution? dead people are embalmed and fluid from this seeps into the ground types of water pollution bacteria, protozoa, and viruses, organic matter (BOD), nitrogen and phosphorous, organic chemicals, and inorganic chemicals (metals) BOD biochemical oxygen demand- surrogate measure of organic materials; bacteria is added, oxygen added then look at how much it degrades drinking water treatment process sedimentation, coagulation, filtration, chlorination, storage, distribution sedimentation removal of sand, gravel, and large particulates coagulation form and remove floc, containing insoluble material and microorganisms filtration remove remaining particulates and most organic and inorganic compounds; sand or activated carbon chlorination kills remaining microorganisms and prevent growth of new inocula; chlorine is used over ozone or UV light because chlorine stays in the water for a longer period, keeping it cleaner longer primary treatment grates and screens; allowed to settle in tanks (clarifiers); separation of solids; effluent still has substantial BOD secondary treatment dependent on bacteria grouping together to settle; aerobic tank, bacteria farm (bacteria eats organic matter; in large concentration so they are starving and want to eat all of it), activated sludge (bacteria is present); flocs normal floc vs. bulking sludge nf: settles well; bs: does not settle properly tertiary treatment nitrogen removal (1st step) ammonia to nitrate; nitrogen present in sewage as ammonia (NH3)- part of protein, nitrosomonas and nitrobacter convert ammonia to nitrate in aeration basins ; this is called nitrification and consumes a great deal of oxygen tertiary treatment nitrogen removal (2nd step) nitrate to nitrogen gas; nitrate is converted to nitrogen gas denitrification by bacteria; nitrogen gas bubbles out of wastewater; requires special design of wastewater plant; beneficial because reduces energy required for wastewater treatment tertiary treatment- phosphorous removal mechanism of phosphorous removal discovered accidentally in south africa 35 years ago; a group of bacteria called PAO's will remove phosphorous under the appropriate conditions; involves cycling bacteria between anaerobic and aerobic conditions