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“Let’s talk about poop, baby”. The day every five-year old boy dreams of …. Warm Up. True/False. Shower, sink, and toilet water leave your home through the same pipe. Where does wastewater from your home go?. ?. ?. Not in here, buddy.
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“Let’s talk about poop, baby” The day every five-year old boy dreams of…
Warm Up • True/False. Shower, sink, and toilet water leave your home through the same pipe. • Where does wastewater from your home go? ? ?
Not in here, buddy • Developing world: human waste disposal similar to pre-modern times • Waste Ditches and cesspools • Outhouses • 1596- John Harington designed the toilet; Thomas Crapper an early toilet maker in U.K. • “The Great Stink” of 1858- London smelled so bad the government decided to construct an underground sewer for the city
Wastewater- water that contains waste from homes or industry Goal of WWT- make water clean enough to return to a water source (river or lake) without damaging ecosystem Wastewater Treatment
Primary Treatment • Filtration- wastewater passed through large screen to remove solid objects • First Settling Tank (sedimentation)- WW moved to large tank where solids settle and are later removed as sludge Settling Tank
Secondary Treatment • Aeration Tank- WW mixed with oxygen and aerobic bacteria to break down waste biologically • 2nd settling tank- bacteria and other solids are removed as sludge • Chlorination- chlorine is added to disinfect water before being released to water body Question: What is the difference between aerobic and anaerobic?
Tertiary Treatment • Goal- remove anything primary and secondary didn’t remove such as: • Nutrients- Nitrogen and Phosphorus • Odor and other pathogens • UV light • Ozone • More chlorine Question: Why would we want to remove nitrogen and phosphorus?
What about the sludge? • Sludge can contain toxic substances • Heavy metals: Mercury, Lead, Cadmium • Organic pollutants • Pathogens • Where does it go? • Land: hauled to landfills • Oceans: Europe still dumps 35-45% of total vol. • Air: incinerated (burned); ash brought to landfill
Sludge Alternatives • Fertilizers for crops • Soil conditioner (like compost) • Reclaiming a landfill for open space or park • Recycled into different materials • Bricks • Biofuels But...the sludge needs to be treated first to remove heavy metals and other toxins- $$
Septic Systems • A home WWTP for rural areas • Residential wastewater flows into buried tank on property • Solids settle in tank, liquids are distributed throughout pipe network in soil called the “drain field” • Soil bacteria break down liquid waste, purifies water before it re-enters the aquifer • Sludge gets removed periodically
Septic Systems 1. Septic Tank 2. Drainfield 3. Sludge Removal 1 2 3
When it hits the fan…Issues • Unmaintained septic systems • E. Coli, fecal coliform bacteria in water • Water-borne diseases: Cholera, Dysentary • Dumping hazardous chemicals into toilet, sink
Combined Sewer Overflows (CSOs) • In older towns and cities, storm water and wastewater sewers are connected- all goes to WWTP • During heavy rainstorms, WWTP cannot handle the extra load of wastewater • So…what do you think happens?!
What can you do at home? • Do NOT pour hazardous materials down the drain, toilet, or shower • Paint • Paint Thinner • Chemicals • Do NOT pour excessive fats, grease, oils, or dead pets down the drain
Wrapping Up… Complete Poop Day recap before you leave today