Units and Measurement

Units of concentration• ppmM (for solids and Liquids)

• ppmV (For gases, consider Temp & Pressure)

• difference between mg/L and ppm

• Molarity

• Molality

• Normality (Concept of Equvalent weight)

Acid and Bases (pH = -Log10[H+]• Weak acid (less than 100% dissociation)

• Strong Acids (100% dissociation)

• Buffers

Mass BalanceMass Balance Batch Reactor

CSTR

First Order Kinetics

Zero Order Kinetics

Dissolution of gases in Water

Henrys Law:• XA = KHpA

– Important to remember: XA is mole fraction of gas in water

Toxicity & Dose Response

Mutagen

Teratogenattacks Germ Cel

Carcinogen(attacks Somatic Cells)

Transmissible to Progeny Lead to Cancer(not death necessarily)

Methods to Test Toxicity

Epidermiologic Data Analysis From past incidences

• Love Canal, Kippon Disaster, Chernobile, Bhopal

Controlled Animal Testing Use of bacteria to Chipms

• Controlled Human Studies Doctors office (the free Treatment)

Dose Response Curve

Points to RememberCarcinogen: No Threshold

LD50: 50% of subject dies

How to Calculate Cancer RiskHow to Calculate Cancer Risk

Risk = CDI * Potency factor

CDI: Chronic Daily Dose

CDI=

TotalDose

AverageBody Weight *Average LifeSpan

Water Quality

Soilds• Total dissolved solids

• Suspended Solids

• Volatile Suspended Soilds

Liquid• Hardness

• Alkalinity

• BOD, BODu, BOD5, BODt

More on Water QualityMore on Water Quality

BODDO DO B B P

Pial final initial final

5

1

int ( )( )

ThoD: Theoretical Oxygen Demand

BODt =BODu(1-e-k1

t)

Temperature Dependence of BOD

KT=K20(T-20)

Steeter Phelps Equation

How to find critical DO and the distance when it happens