Presentation on theme: "Drinking Water and Wastewater Treatment"— Presentation transcript:
1 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”Sand filters became common in 1700sUrban water was poorer than water from forested watershedsChlorination was introduced in 1907.
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 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 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, chloraminesBOD - biochemical oxygen demand; biological oxygen demandDistribution: storage and pressure
13 The water 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.
14 BODThe amount of oxygen used by microorganisms in the process of breaking down organic matter in water.The more organic matter there is (e.g., in sewage), the greater the number of microbes. The more microbes there are, the greater the need of oxygen to support them; consequently, less oxygen is available for higher animals such as fishes.The BOD is therefore a reliable gauge of the organic pollution of a body of water.One of the main reasons for treating sewage or waste water prior to its return to a water resource is to lower its BOD-i.e., reduce its need of oxygen and thereby lessen its demand from the streams or rivers into which it is released.
18 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
19 Lead in Drinking Water Sources: lead solder and pipes Problem: behavior problems and learning disabilities
20 Drinking Water from Wells City wells are routinely testedPrivate water wells are seldom testedSources of contamination include wastewater, landfills, junkyards
25 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
26 Wastewater DisposalWastewater leaves homes thru property laterals and enters City Sewer System. Sewers increase in size as Collection System moves wastewater into Interceptor Lines.
27 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
28 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.
32 First U.S. operation: The Fessenden, North Dakota, sewage lagoon is famous in the realm of wastewater treatment around the world.
33 Septic Tanks and Leach Fields Septic tank collects biosolids and breaks them down. Aerobic decay requires oxygen, anaerobic 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
35 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.
37 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
39 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
40 Chapter 13: 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.