Wastewater Treatment Powerpoints
CATALYST
• Plankton are important _AUT ___________ OT ROPHS in a marine food web. • Ocean _________ GYRES are large systems of circular ocean currents formed by global wind pa7erns & Earth’s rota<on. • The _GREAT ______ Pacific _GARBAGE _________ Patch is a collec<on of marine debris in the North Pacific Ocean
CATALYST
• ______ POINT Source: Direct discharge into water • ____________ NONPOINT Source: Indirect discharge into water (runoff)
OCEAN POLLUT ION
• Yesterday, we discussed “microplas<cs” and plas<c soup that is found in the ocean • Today we will talk more about liquid pollu<on & how to treat wastewater
SEWAGE & WASTEWATER • Wastewater needs to be managed in order to reduce threats to public health, safety, & the environment • Wastewater can consist of industrial waste, human waste (sewage), or runoff from rainwater • ALL of the wastewater produced by a city eventually ends up in a river, lake, or ocean. SOURCE: h@p://www.learner.org/interacDves/garbage/sewage.html
SEWAGE & WASTEWATER • 30 years ago, thousands of American ci<es dumped their raw sewage directly into our naDon's rivers, lakes, & bays • Today, because of improved wastewater treatment, our waterways have been cleaned up & made safer for recrea<on and seafood harvest
SEWAGE & WASTEWATER • On its way, this wastewater flows through a sewage treatment plant
SEWAGE & WASTEWATER • Basic stages of the wastewater treatment process include:
1. Screening for larger parDcles 2. AeraDon to release gases 3. Sludge that sDmulates good bacteria 4. Sludge se@les & is removed; scum floats & is removed 5. Chlorine tank
WASTEWATER T REAT MENT
1. Screening: Wastewater entering the treatment plant includes items like wood, rocks, & even dead animals. These large par<cles are screened, removed, & sent to a landfill
SEWAGE & WASTEWATER 2. AeraDng: Shakes up the sewage & expose it to air causing some of the dissolved gases (such as hydrogen sulfide, which smells like ro7en eggs) to be released from the water.
SEWAGE & WASTEWATER 3. Sludge: Sludge is produced from the treatment of wastewater in on-‐site (sep<c tank) & off-‐site (ac<vated sludge) systems
SEWAGE & WASTEWATER
• This sludge helps to break down wastewater • The sludge sDmulates the growth of oxygen-‐using bacteria & other <ny organisms that are naturally present in the sewage
SEWAGE & WASTEWATER • These microorganisms consume most of the remaining organic materials that are pollu<ng the water & this produces heavier par<cles that will se7le later in the treatment process
SEWAGE & WASTEWATER 4. SedimentaDon: Sludge se7les to the bo7om to be removed; scum including grease, oils,
plas<cs, & soap float to the top • Slow-‐moving rakes skim the scum off the surface of the wastewater
SEWAGE & WASTEWATER 5. Chlorine tank: The wastewater flows into a 'chlorine contact' tank, where the chlorine is added to kill bacteria, (like in swimming pools)
WASTEWATER T REAT MENT
Water Pollution
• If waste is not handled properly, it may result in water polluDon • Water PolluDon: the degrada<on of water quality (physical, chemical, or biological proper<es) • Water Quality: • How clean/pure the water is • What its physical, chem. bio. props are • Does it meet water quality standards
Water Quality
• Water quality standards: • If standard exceeded, water can’t be used for intended purpose • Drinking water standards are more stringent than those for rivers & streams • MCL: Maximum Contaminant Level: Max. level of contaminant allowed – if exceeded, water can’t be used for intended purpose & fines may be imposed
How is it measured?
• Scien<sts use instruments like Secchi disks, probes, nets, gauges, & meters to determine how healthy the water is • They take measurements of the physical & chemical condi<on of the water & the health of the cri7ers that live in it • The Secchi disk (1865) is a plain white, circular disk used to measure water transparency in bodies of water. The disc is mounted on a pole or line, & lowered slowly down in the water
Secchi Disk
• The Secchi disk (1865) is a plain white, circular disk used to measure water transparency in bodies of water.
What do they measure?
• Temperature: Determines the kinds of animals that can survive in a stream; can affect the chemistry of the water
• Dissolved Oxygen (DO): Tells scien<sts how much oxygen is available in the water for fish & other aqua<c organisms to breathe
What do they measure?
• pH: Scien<sts measure pH to determine the concentra<on of hydrogen in the water • The p stands for “poten<al of” & the H is Hydrogen
What do they measure?
• Toxic Substances: • Things like metal, pes<cides, & oil.
What do they measure?
• Turbidity: • Scien<sts measure the clarity of water to determine how many parDculates (li7le bi7y par<cles of stuff) are floa<ng around • Low Turbidity: Clear, you can see the bo7om
• High Turbidity: Murky, you can’t see the bo7om
What do they measure?
• Bacteria: Scien<sts sample for certain types of bacteria that are found only in the intesDnal tract/feces of animals & humans • These bacteria, called fecal coliforms, are not necessarily harmful, but are associated with viruses & pathogens, which can make you sick
FECAL COLIFORM
• Major sources of fecal coliforms are failing sep<c systems, wastewater treatment plant discharges, & animal waste
What do they measure?
• Biological sampling: Scien<sts determine the health of waters by taking samples of fish, plants & smaller organisms called macroinvertebrates
• Macroinvertebrates include things like snails, worms, fly larvae, & crayfish ("crawdads”)
SOURCE: h7p://water.epa.gov/learn/resources/measure.cfm
Indicator Species
• One of the most common indicator species used to measure air pollu<on are lichens • Fresh water shrimp & mayfly larva indicates clean water • Rat-‐tailed maggots or sludge worms survive well in polluted waters
What do they measure?
• Nutrients: • The two major nutrients scien<sts measure are nitrogen & phosphorus
• The presence of too many nutrients can hurt aqua<c organisms by causing lots of algae to grow in the water
Eutrophication
• High nutrients: • • • • • • •
Increased algae growth Light level below surface drops due to algae Algae eventually dies Increased bacterial ac<vity Lower oxygen concentra<on Fish & other organisms die Thus affec<ng the en<re ecosystem
Eutrophication
Preventing Eutrophication • Decrease use of phosphate containing detergents, etc. • Control agricultural runoff (be7er irriga<on prac<ces, using less fer<lizer, more buffers) • Control urban runoff (golf courses, parks, homes, landscaping) • Advanced treatment & use of wastewater
PracDce QuesDon 1. The water found in subterranean spaces, cracks, and open pore spaces of minerals is called A. Watershed B. Groundwater C. Snow melt D. Run off E. Evapotranspira<on