同济大学：《水资源管理》课程教学资源（教案讲义）04 Water Quality Modeling、Reactions & Transport、Dissolved Oxygen Modeling in Rivers、Eutrophication

Lecture 1: Introduction to Water Quality Modeling 1907

Lecture 1: Introduction to Water Quality Modeling

LECTURE 1 Introduction to Water Quality Modeling and Numerical Methods 米What is water quality modeling？ 米Mass balance *Analytical solutions 米Numerical solutions

LECTURE 1 Introduction to Water Quality Modeling and Numerical Methods What is water quality modeling? Mass balance Analytical solutions Numerical solutions

URBAN POINT SOURCE DESIGN PROBLEM (Circa 1920s) River Critical concentration,c [M/L3] Waste loading,W[M刀 WTP WWTP Waste removed CITY WATER-QUALITY MODEL: c fW,physics,chemistry,biology)

WATER-QUALITY MODEL: URBAN POINT SOURCE DESIGN PROBLEM (Circa 1920s) WTP Waste removed CITY Waste loading, W [M/T] Critical concentration, c [M/L3 ] WWTP River c = f(W, physics, chemistry, biology)

MODELS GIVE YOU THE BIG PICTURE AN ELEPHANT IS LIKE A BRUSH AN ELEPHANT IS LIKE A AN ELEPHANT ROPE IS LIKEA SNAKE AN ELEPHANT IS LIKE A TREE TRUNK

AN ELEPHANT IS LIKE A SNAKE AN ELEPHANT IS LIKE A BRUSH AN ELEPHANT IS LIKE A TREE TRUNK AN ELEPHANT IS LIKE A ROPE MODELS GIVE YOU THE BIG PICTURE

THE COMPUTER MODEL TIES EVERYTHING TOGETHER ECONOMICS CHEMISTRY AIRSHED PHYSICS THE BIOLOGY MODEL WATERSHED GROUNDWATER

BIOLOGY THE COMPUTER MODEL TIES EVERYTHING TOGETHER THE MODEL CHEMISTRY PHYSICS ECONOMICS WATERSHED GROUNDWATER AIRSHED

MASS AND CONCENTRATION m mass volume M units: L3 note:M mass,L length,T time,H heat

MASS AND CONCENTRATION c = m V m = mass V = volume note: M = mass, L = length, T = time, H = heat M units: L3

MASS →AMOUNT OF SUGAR CONCENTRATIONSWEETNESS

MASS AMOUNT OF SUGAR CONCENTRATION SWEETNESS

CONCENTRATION UNITS g,0上、 g g m3 0鸿 m3 g g 3 g =1 ppm m3 106cm3 100 mg g ppm

CONCENTRATION UNITS g 103 mg  g m3  L m3  103 g m3 m3 106 cm3  g  106 g  1 ppm mg L g  m3  ppm mg L  g m3 g cm3 1

1 teaspoon Salt≥20ppt Sugar≥20ppm Phosphorus≥20ppb

1 teaspoon Salt  20 ppt Sugar  20 ppm Phosphorus  20 ppb

TYPICAL UNITS FOR WATER-QUALITY CONSTITUENTS 0.10mg/L Variables Units total dissolved solids,salinity gL→kg/m3→ppt oxygen,BOD,nitrogen mgL→g/m3→ppm phosphorus,chlorophyll a,toxics gL→mg/m3+→ppb toxics ng/L→ug/m3→pptr

Variables Units total dissolved solids, salinity g/L kg/m3 ppt oxygen, BOD, nitrogen mg/L g/m3 ppm phosphorus, chlorophyll a, toxics g/L mg/m3 ppb toxics ng/L g/m3 pptr TYPICAL UNITS FOR WATER-QUALITY CONSTITUENTS 0.1 < c < 100 10,000 g/L 10 mg/L