Water Pollution:Contaminants and Testing Procedures

Presented byM. Baranitharan

Computer Science and EngineeringKings College of Engineering

What is Water Pollution?

• Water pollution - any change in water quality that harms humans or other living organisms or makes water unsuitable for desired uses.

Application: “The Mistake by the River”

Cuyahoga River in the Fall©Tom Jones

http://csudigitalhumanities.org/exhibits/items/show/1328

A Burning River?

The Plain Dealer File

http://oceanservice.noaa.gov/education/kits/pollution/02history.html

http://www.youtube.com/watch?v=tZA9OX2joUc&feature=related

What are the sources of water pollution?

• Point Sources– Can be traced back to one

particular origin• Industrial Plants (Power,

Chemical, Waste Treatment)• Drain pipes, Sewer Lines,

Underground Mines

• Nonpoint Sources– Tend to be widespread with

many regions contributing to the water pollution.

• Agricultural Runoff• Stormwater Runoff (Roads and

Parking Lots)Fig. 11-23, p. 260

Types of Contaminants• Pathogens – Wastes from Humans and Animals• Plant Nutrients – Nitrates & Phosphates• Organics – Oil, Gasoline, Plastics, & Pesticides• Inorganics – Salt, Metal Compounds• Sediment – Total Suspended Solids• Heavy Metals• Thermal

Most Commonly Tested Parameters

• Temperature• pH• Nitrates• Phosphates• Dissolved Oxygen• Turbidity• Specific Conductivity• Total Dissolved Solids• Total Suspended Solids

Water Quality Index

Water Quality Index (WQI) is a measure of how polluted a body of water actually is.

It can take many different parameters into consideration. (6 parameters are typically used to calculate WQI)

Utilizes a weighting factor to differentiate between important parameters and less-important parameters.

Q-Values are numbers that are given in a table and correlate to the level of each parameter to characterize each on a scale of 0-100 (100 being best)

Water Quality Index

Test Result Q-Value Weight Factor Subtotal Dissolved Oxygen 103.1% Sat. 0.17

Fecal Coliform 2 / 100mL 0.16

pH 7.59 0.11

BOD (5-day) 1.75 mg/l 0.11

Temperature 1°C 0.10

Phosphates .45 mg/l 0.10

Nitrates .6 mg/l 0.10

Turbidity 50 cm 0.08

Total WQI

Water Quality Index

Test Results

Q-Value

Q-Value X

Weighting Factor

Add all Subtotals

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90   0.3  

Nitrate 1.75   0.2  

Phosphate 0.3   0.2  

pH 6.70   0.3  

Totals        

Water Quality Index

Dissolved Oxygen: % saturation = 90

1. In the DO column find the value equal to 90.

2. Write down the Q-Value to the right of that number (Q-value = 95).

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90  95 0.3 95 X 0.3 = 28.5 

Nitrate 1.75   0.2  

Phosphate 0.3   0.2  

pH 6.70   0.3  

Totals        

Water Quality Index

Nitrate: 1.75 mg/L

1. In the Nitrate-N Column find the values closest to 1.75. This number falls between 1.5 and 2 in this column

2. Since there is no value matching exactly to 1.75, estimate the Q-value between 92 and 90 (Q-value = 91).

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90  95 0.3 28.5 

Nitrate 1.75  91 0.2  91 X 0.2 = 18.2

Phosphate 0.3   0.2  

pH 6.70   0.3  

Totals        

Water Quality Index

Phosphate: 0.3 mg/L

Water Quality Index

Phosphate: 0.3 mg/L

1. In the Total Phosphate column find the value equal to 0.3 (similar to the dissolved oxygen).

2. Write down the Q-Value to the right of that number (Q-value = 90).

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90  95 0.3 28.5 

Nitrate 1.75  91 0.2 18.2

Phosphate 0.3 90  0.2 90 X 0.2 = 18.0 

pH 6.70   0.3  

Totals        

Water Quality Index

pH: 6.70

1. In the pH column find the values closest to 6.70. This number falls between 6 and 7.

2. Since there is no value matching exactly to 6.70, estimate the Q-value between 55 and 90 (Q-value = 81).

Water Quality Index

pH 6 7

Q-value 55 90

Water Quality Index

pH 6 6.5 7

Q-value 55 72.5 90

(55+90) / 2 = 72.5

Water Quality Index

pH 6 6.5 6.75 7

Q-value 55 72.5 81.25 90

(72.5+90) / 2 = 81.25

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90  95 0.3 28.5

Nitrate 1.75  91 0.2 18.2

Phosphate 0.3 90 0.2 18.0

pH 6.70  81 0.3  81 X 0.3 = 24.3

Totals        

Water Quality Index

Parameter Tested Value

Q-Value Weighting Factor

Calculation

Dissolved Oxygen

90  95 0.3 28.5

Nitrate 1.75  91 0.2 18.2

Phosphate 0.3 90 0.2 18.0

pH 6.70  81 0.3  24.3

Totals        28.5 + 18.2 + 18.0 + 24.3

= 89.0

Water Quality Index

Water Quality Percentages

Excellent 90-100%

Good 70-90%

Medium 50-70%

Bad 25-50%

Very Bad 0-25%