AP Environmental Science Exam Review Wastewater
Wastewater Infectious Agents = cholera and typhoid fever Any water that has been used by humans. Human sewage Water drained from showers, tubs, sinks, dishwashers, washing machines Water from industrial processes Storm water runoff In the U.S. = Moved through sewage pipes to a sewage treatment facility. In developing countries = dumped into nearest river or ocean.
Municipal Sewage Treatment Plants Physical Treatment – removes debris Stones, sticks, rags, toys, objects flushed down toilets Debris is separated and sent to a landfill Primary Treatment – remaining water is passed into a settling tank Suspended solids settle out as sludge Chemically treated polymers may be added to help Removes about 60% of the suspended solids and 30% of the organic waste that requires oxygen in order to decompose
Municipal Sewage Treatment Plants, ctd Secondary Treatment – the biological treatment of wastewater in order to continue to remove biodegradable waste; 97% suspended solids, 96% organic waste; 70% toxic metals, organic chemicals, and phosphates; 50% of nitrogen; and 5% dissolved salts have been removed. Trickling filters – aerobic bacteria digest waste as it seeps over bacteria-covered rock beds Sludge processor – a tank filled with aerobic bacteria Solids are left out to settle Sludge – solids left after treatment Combined with solids from primary treatment, is burned, deposited in a landfill, or dumped in the ocean Sludge burned = contains methane, which can be used to provide the electrical power to run the waste facility Gray Water – (after secondary trtmnt) water is chlorinated to remove any living cells, then discharged into a stream, the ocean or water that’s used to water lawns.
Tertiary Treatment Involves passing the secondary treated water through a series of sand and carbon filters, then more chlorination. San Jose Creek Plant (LA Cty, CA) – tertiary treated water from the reclamation plants is discharged into percolation basins. Tertiary Treatment is expensive, but in arid or semi-arid regions any gallon of water that can be reclaimed is needed.
Private Wasterwater Treatment Septic Tanks – act in a way that is similar to the primary and secondary treatments at municipal plants. Water is discharged into leachate fields. To have a septic system – soil must be able to percolate the water Some clay soils are not porous enough to allow percolation = unsuitable for a sanitation field
Which of the following choices gives the correct order of processing sanitary waste in a sewage treatment plant? A. Disinfection – breakdown of organics by bacteria – solid separation B. Solid separation – breakdown of organics by bacteria – disinfection C. Solid separation – disinfection – breakdown of organics by bacteria D. Breakdown of organics by bacteria – solid separation - disinfection E. Breakdown of organics by bacteria – disinfection – solid separation
The presence of which of the following contaminants would be the strongest reason for judging municipal sewage sludge unfit for use as fertilizer? A. Human feces B. Ammonia C. Phosphates D. Nitrates E. Heavy metals
The dangers of disposing of toxic chemicals underground came to public attention in which of the following locations? A. Bhopal, India B. Chernobyl, Ukraine C. Love Canal, New York D. Minamata, Japan E. Three Mile Island, Pennsylvania
Backpack Transported into factories Provides job Mined sometimes and away as zippers.Greenhouse opportunities under hazardous Larger Carbongas emission conditions. Footprint. Transportation Nitrous oxide Aluminum nylon Nylon coal water Nonrenewable resource Dangerous Polyester Used for school supplies and or working work conditions in coal mines Less greenhouse Made of gas emission than synthesized fibers Nylon. Outer backpack material Nylon