2.  Waste and wastewater produced by residential and commercial users that is discharged into sewers  Ex: Human waste, soaps, paints, oils  Storms intensify spread->wash off into drainage systems

3.  Microorganisms  Viruses, bacteria, protozoa and parasites  Can spread waterborne diseases via fecal-oral transmission

4.  Pathogens  Microorganisms that can cause disease  Can cause diarrhea, schistosomiasis (disease caused by parasitic worms), intestinal worms, and river blindness

5. Eliminates up to 99.99% of microorganisms – Drinking water: Chlorine- kills microorganisms Filtration- removes particulate matter Collected and transported via a network of pipes and pump stations to a municipal treatment plant

6.  Primary  solids are separated  Secondary  dissolved biological matter is converted into a solid mass by using water-borne bacteria  95% of the suspended molecules should be removed  Tertiary  biological solids are neutralized then disposed, and treated water may be disinfected chemically or physically

7.  Mechanical treatment  Influx (Influent)  Removal of large objects  Removal of sand and grit  Primary Sedimentation  Biological treatment  Trickling bed filter  Activated sludge  Chemical treatment  Disinfection

8.  Remove large objects  Ex: sticks, rags, toilet paper, tampons  Raked screen  Clog equipment in sewage treatment plant

9.  Typical materials that are removed during primary treatment include  fats, oils, and greases (aka FOG)  sand, gravels and rocks (aka grit)  larger settleable solids including human waste  floating materials

10.  Primary Sedimentation Tank  Remove grease, oil  Fecal solid settle, floating material rise to the surface  Produce a homologous liquid for later biological treatment  Fecal sludge are pumped to sludge treatment plant

11.  Degrade biological content (dissolved organic matter) of the sewage  Ex: human waste, food waste, soaps, detergent  Added bacteria and protozoa into sewage  3 different approaches  Fixed film system  Suspended film system  Lagoon system

12. 1. Fixed Film Systems – grow microorganisms on substrates such as rocks, sand or plastic – wastewater is spread over the substrate – Ex: Trickling filters, rotating biological contactors

13.  Trickling Filter Beds  Spread wastewater over microorganism  made of coke (carbonized coal), limestone chips or specially fabricated plastic media  Optimize their thickness by insect or worm grazing

14. 2. Suspended Film Systems  stir and suspend microorganisms in wastewater  settled out as a sludge  pumped back into the incoming wastewater  Ex: Activated sludge, extended aeration

15.  Mixed community of microorganisms  Both aerobic and anaerobic bacteria may exist  Biological floc is formed (bacteria and protozoa)

16. 1. Aeration tank  oxygen is introduced into the system

17. 2. Aeration source – ensure that adequate oxygen is fed into the tank – provided pure oxygen or compressed air

18. 3. Secondary clarifiers – activated-sludge solids separate from the surrounding wastewater

19. 4. Activated sludge outflow line – Pump activated sludge back to the aeration tank 5. Effluent outflow line – discharged effluent into bay or tertiary treatment plant

21.  Sewage Treatment Sewage Treatment

22.  Remove disease-causing organisms from wastewater  3 different disinfection process  Chlorination  UV light radiation  Ozonation

23.  Most common  Advantages: low cost & effective  Disadvantages: chlorine residue could be harmful to environment

24. Damage the genetic structure of bacteria, viruses and other pathogens. Advantages: no chemicals are used water taste more natural Disadvantages: high maintenance of the UV-lamp

25.  Oxidized most pathogenic microorganisms  Advantages: safer than chlorination fewer disinfection by-product  Disadvantage: high cost

27.  Measures the number of coliform bacteria per 100 milliliters  Coliform lives in guts of most mammals  Do not usually cause disease->used as proxy for presence of other microorganisms that can cause disease  Water should have a count of 0  Swimming or “full body contact”-count <200

28.  Not available in many developing nations  250 million cases of waterborne disease each year killing 5-100 million people  Children highly susceptible  Diarrheal disease->underweight, mental/physical hanidcaps, vulnerable to other diseases

29.  Discharging too much into surface waters can cause eutrophication (decreases oxygen levels)  Microorganisms metabolize organic wastes->use oxygen faster than it can reenter atmosphere  If water becomes anoxic, decomposition proceeds anaerobically, and releases noxic gases

31.  Increase in algae growth  Increase in zooplankton  Even more eutrophication  Oxygen depletion  Zooplankton and fish suffocate or are poisoned by toxins  Water has a foul taste and odor

33. ***Focus on Phosphorus Waste water treatment Ban on Phosphorus containing detergents Reduce use of fertilizers Control agricultural runoff Reduce use of phosphorus in animal feed ->less phosphorus in manure

34.  Sediments, heavy metals, xenobiotics (organic compounds that are synthesized by humans and are resistant to organic decay)  Heavy metals->greatest threat: cancer, damage to nervous system, birth defects  Highest concern: lead, mercury, cadmium, and arsenic

35.  Point: directly discharged into a body of water  Ex: Pipe or smokestack  Ex: GE and Hudson River->PCB’s  Nonpoint: not discharged from a specific point  Ex: pesticides and herbicides Leach through soil and contaminate ground water Runoff from farms into other bodies of water