Presentation on theme: "Chapter 11: Drinking Water and Wastewater Treatment"— Presentation transcript:
1 Chapter 11: Drinking Water and Wastewater Treatment Historical PerspectiveFederal Protection of Drinking WaterTreatment ProcessWastewater
2 Drinking Water: Historical Perspective The Greeks and Romans recognized that poor water quality caused disease and deathBathing once or twice a year was “healthy”During Middle Ages conditions deterioratedSand filters became common in 1700s in FranceChlorination was introduced in 1909 in NJ.
3 Potable Water Water used for drinking, cooking, and washing Requires filtering, disinfection, desalinizationGroundwater has natural filtration, may need disinfectionNew York City does not filter suface water because it is from forested areas.Reverse osmosis is needed to remove salts.
7 Water Quality Concerns PathogensBacteria (E. coli, fecal strep, cholera)Viruses (polio, hepatitus)Protozoa (Giardia)Dysentary (Amoeba and Shigella)Emerging ContaminantsEndocrine disruptors (contraceptives)Antibiotic resistant pathogens, pharmaceuticalsMetals (lead, arsenic), Organics (gasoline, herbicides)
8 Federal Protection1914: U.S. Treasury established a limit of 2 coliforms per 100 mL for drinking water1942: U.S. Public Health Service standardized drinking water standards1948: Federal Pollution Control Act1974: Safe Drinking Water Act1986: Wellhead Protection Program1996: Source Water Assessment and Protection
9 Figure This intake structure for the Mount Werner Water Filtration Plant is located near the mouth of Fish Creek Canyon above Steamboat Springs, Colorado.
10 Drinking Water Standards, 2004 Copper (liver and kidney damage) 1.3 mg/LFluoride (bone disease) 4.0 mg/LNitrate (Blue Baby syndrome) 10 mg/LNitrite (same) 1 mg/LDioxin (cancer) No detectibleXylenes (nervous system damage) 10 mg/LAtrazine (Cardiovascular damage) mg/L
11 Figure Raw water from the Mississippi River is pumped to the Carrollton Water Purification Plant, one of two such plants that serve the city of New Orleans.
12 Drinking Water Treatment Watershed and wellhead protection: prevents contaminationDiversion, storage, and intakeFlocculation/coagulation => settlingFiltrationFluoridationDisinfection: Cl2, O3, UV, chloraminesDistribution: storage and pressure
14 Figure The water tower at Clarkson, Nebraska, is located on a hill in the farming community of 700 residents in eastern Nebraska.
15 Figure 11.5 Water intake clogged with Zebra Mussels.
16 Flouride and Tooth Decay Flouride is added to strengthen teeth and bonesMany communities add F to improve teethDentists can tell whether you grew up on city water or notAdding too much causes brittle bones
17 Lead in Drinking Water Sources: lead solder and pipes Problem: behavior problems and learning disabilities
18 Drinking Water from Wells City wells are routinely testedPrivate water wells are seldom testedSources of contamination include wastewater, landfills, junkyards
29 Wastewater: Historical Perspective A major problem since the earliest citiesMost went down roads to the nearest stream1370: First underground sewers1867: First wastewater treatment (London)1928: First U.S. operation (Fessenden, ND)1964: First Athens treatment plant
30 Figure The Fessenden, North Dakota, sewage lagoon is famous in the realm of wastewater treatment around the world.
31 Wastewater Treatment Process Primary Treatment: Remove large debris (sand, stones, garbage)Secondary Treatment: Break down organic matter by adding oxygen to promote decayTricking filter: Water cascades down over coarse materials (stones, balls)Activated sludge: Large motors churn air into the waterTertiary Treatment: Nutrient Removal
33 Figure The wastewater treatment process at larger facilities includes numerous steps such as bar screen, grit removal, primary and secondary settling tanks, aeration, flocculation and coagulation, sand filters, and chlorination.
34 Septic Tanks and Leach Fields Septic tank collects biosolids and breaks them down. Aerobic decay requires oxygen, anaeorobic decay does not. Facultative decay is when both are present.Leach field takes water that has gone through the septic tank, and is allowed to percolate through the soil
36 Wetlands and Water Treatment Similar to the original Fessenden plan.Natural biodegradation and nutrient removal.Good environment (mixed aerobic and anaerobic) for facultative bacteria.Provides habitat, increases water storage and prevents overflows during wet weather.
38 CSOs Combined Sewer Overflows Used to carry sewage to treatment plant during dry weatherAlso collects stormwater during wet weatherSystem is overloaded during big storms, and is routed directly to the river
40 NPDES Permit National Pollution Discharge Elimination System Used to regulate wastewater dischargesRequires a minimum treatment standardDissolved Oxygen, pH, BOD, ammonia, toxicityThese permits get more strict over time as more users need to add to the river
41 Chapter 11: Quiz1. Describe how large particles are removed during drinking water treatment.2. Adding ____________ to drinking water helps to prevent cavities.3. Name one process for disinfection:4. Name and describe the three steps in wastewater treatment:a.b.c.