CEE 371 Water and Wastewater Systems

Transcription

1 Updated: 21 November 2009 CEE 371 Water and Wastewater Systems Print version Lecture #11 Water and Wastewater Quality Reading: Chapter 5, pp David Reckhow CEE 371 L#11 1 Generalized Decision Tree Heath Effects/ Assessment Is there a significant hazard? Determine MCLGs for Highest Risk Pathogens & DBPs Occurrence/ Exposure Analytical Methods Can we control the hazards? Treatment Technologies 2 MCLs with BAT Treatment Technique TT Both 2 Lecture #11 Dave Reckhow 1

2 Activity Smoking 1.4 cigarettes Spending 1 hr. in a coal mine Living 2 days in NYC or Boston Living 2 months in Denver Comparative Risks All increase chance of death in any year by One chest X-ray Eating 40 tbs. of peanut butter Drinking oz. cans of diet soda Living 150 yrs. within 20 miles of a nuclear power plant Cause of Death Cancer, heart disease Black lung disease Air pollution Cancer caused by cosmic radiation Cancer caused by radiation Liver cancer caused by Aflatoxin B Cancer caused by saccharin Cancer caused by radiation See: Science article on value assigned to human life David A. Reckhow CEE 577 #1 3 Surface Water Treatment Rule (SWTR) General Requirements Purpose is to ensure that t public water systems using surface waters protect against waterborne diseases; special consideration to viruses and Giardia lamblia States conditions where filtration is required as a treatment technique as well as conditions for which disinfection is the only treatment Treatment technique requirements established in lieu of MCLs for Giardia, viruses, Inactivation/removals of: will also protect against HPC bacteria and Legionella 99.9 percent (3 log) for Giardia cysts percent (4 log) for viruses 4 Compliance required with THM MCL of 0.10 mg/l (100 μg/l) 4 Lecture #11 Dave Reckhow 2

3 SWTR (cont.) Multiple Barrier Concept Filtered Systems: Source Water Protection o Filtration Disinfection Unfiltered Systems: Source Water Protection Including wellhead protection 5 Disinfection 2 different ones 5 SWTR (cont.) Requirements for Filtered Supplies Log 10 Removal Allowed Remaining Log 10 Type of By Filtration Inactivation by Disinfection Filtration Giardia Viruses Giardia Viruses Conventional Direct Requirements for Unfiltered Supplies Meet source water quality criteria Provide all Pathogen removal by Disinfection 3 log Giardia, 4 log viruses 6 Requires a certain CT 6 Lecture #11 Dave Reckhow 3

4 Engineering & Disease Filtration & chlorination From: The Sanitary City David Reckhow CEE 371 L#10 7 John #1: Dr. John Snow Cholera First emerged in early 1800s : The third cholera pandemic Snow showed the role of water in disease transmission London s Broad Street pump Miasma theory was discredited, but 8 it Lecture #11 Dave Reckhow 4

5 9 John #2: Dr. John L. Leal Jersey City s Boonton Reservoir Leal experimented with chlorine, its effectiveness and production George Johnson & George Fuller worked with Leal and designed the system (1908) Full-scale and continuous implementation of disinfection for the first time in Jersey City, NJ ignited a disinfection revolution in the United States that reverberated around the world M.J. McGuire, JAWWA 98(3) Lecture #11 Dave Reckhow 5

6 Leal on chlorine the practical application of the use of bleach (chlorine) for the disinfection of water supplies seems to me to be a great advance in the science of water purification. It is so cheap, so easy and quick of application, so certain in its results, and so safe, that it seems to me to cover a broader field than does any other system of water purification yet used. John L. Leal, Chlorination 1-2 punch of filtration & chlorination Greenberg, 1980, Water Chlorination, Env. Impact & Health Eff., Vol 3, pg.3, Ann Arbor Sci. US Death Rates for Typhoid Fever Melosi, David Reckhow 2000, The Sanitary City, John Hopkins Press CEE 371 L#10 12 Lecture #11 Dave Reckhow 6

7 John #3: Johannes J. Rook John Rook Brewery chemist Started with Rotterdam WW in 1963 Found trihalomethanes (THMs) in finished water in 1972 Carcinogens!?! Deduced that they were formed as byproducts of chlorination Others Uden, Christman Haloacetic Acids (HAAs): 1980 Rook, 1974, Water Treat. & Exam., 23: The downside of chlorination The Precursors! Chlorine (HOCl) + natural organics (NOM) The THMs Cl Cl C H Cl Br Cl C H Cl Br Br C H Cl Oxidized NOM and inorganic chloride Aldehydes Chlorinated Organics TOX THMs HAAs Br Br C H Br Chloroform Bromodichloromethane Chlorodibromomethane Bromoform 14 Lecture #11 Dave Reckhow 7

8 The US regulatory approach A balancing act between adequate disinfection and minimizing disinfection byproducts Higher DBP Levels 15 Better Disinfection 15 T/F Question In a conventional water filtration plant, if you achieve 1 log removal of Giardia by disinfection, you are meeting the SWTR requirements True Fl False David Reckhow CEE 371 L#10 16 Lecture #11 Dave Reckhow 8

9 Secondary standards Aesthetic or cosmetic affects non-enforceable federal standards, but states are free to enforce Still quite politically and economically important See H&H, Table 5-3 Contaminant Secondary Standard Aluminum 0.05 to 0.2 mg/l Chloride 250 mg/l Color 15 (color units) Copper 1.0 mg/l Corrosivity noncorrosive Fluoride 2.0 mg/l Foaming Agents 0.5 mg/l Iron 0.3 mg/l Manganese 0.05 mg/l Odor 3 threshold odor number ph Silver 0.10 mg/l Sulfate 250 mg/l Total Dissolved Solids 500 mg/l Zinc 5 mg/l David Reckhow CEE 371 L#12 17 Purposes for Water Treatment Disinfection Removal of Turbidity Removal of Color, and Tastes & Odors Removal of Iron & Manganese Hardness removal Protection from Toxic Organics and Inorganics David Reckhow CEE 371 L#10 18 Lecture #11 Dave Reckhow 9

10 Surface WQ Management Types of WQ Standards used in US management scheme NPDES 30/30 std 30 day composite avg Excursions to 45 for <7 d 85% removal Waste Load Allocations Fig 5-1, p.151 in H&H David Reckhow CEE 371 L#10 19 Impaired Watersheds in US See: EPA s impaired waters page David A. Reckhow CEE 577 #1 20 Lecture #11 Dave Reckhow 10

11 TMDL Process Water Quality Standards Monitor/Assess WQS Attainment List Impaired Waters Develop TMDL Continuing Planning Process Waste Load Allocation Point Source NPDES Permits Integrated Watershed Plan Load Allocation Control Nonpoint Sources David A. Reckhow CEE 577 #1 21 Managing Groundwater Controlling contamination from point and non-point sources Fig 5-2 from H&H David Reckhow CEE 371 L#10 22 Lecture #11 Dave Reckhow 11

12 Marine Discharge Ocean outfall David Reckhow CEE 371 L#10 23 Ocean Discharge Standards Conventional pollutants Hypoxia is increasingly important David Reckhow CEE 371 L#10 24 Lecture #11 Dave Reckhow 12

13 To next lecture David Reckhow CEE 371 L#11 25 Lecture #11 Dave Reckhow 13