Introduction to Environmental Engineering

Transcription

1 Updated: 9 September 2015 Print version CEE 370 Environmental Engineering Principles Lecture #1 Introduction I Reading: Chapter 1 in Mihelcic & Zimmerman David Reckhow CEE 370 L#1 1 Introduction to Environmental Engineering CEE-370 Lecture 1 Presented by: Rassil and Julie Lecture #1 Dave Reckhow 1

2 Introduction to CEE 370 Syllabus Environmental Engineering The application of science and engineering principles: To care for and/or restore our natural environment To solve environmental problems associated with human activities Impacts everyone and everything Plants Insects Animals Humans Ecosystems Lecture #1 Dave Reckhow 2

3 The Big Picture Human overpopulation (~7,363,183,400) Resource use (land, water, fossil fuels, crops, meat ) Intensive farming Higher meat production and crop farming Increased irrigation Nutrient pollution Land use Desertification Habitat change Land pollution Hydrology Distribution of water resources Quality of water resources Challenges: Fresh water supply Running out of oil Climate change Mounting of solid waste Main Umbrellas - Air Air pollution Acid rain Greenhouse gases CO Particulate matter O 3 at the ground level Pb Nitrogen oxides Sulfur oxides Indoor air quality CO Radon Mold and moisture Lecture #1 Dave Reckhow 3

4 Main Umbrellas - Land Land/soil quality Heave metals: Pb Insecticides Pesticides Fertilizers Petrols, oils, solvents etc.. Ash Main Umbrellas Drinking Water Water quality Surface water Ground water Microorganisms (Fecal and total coliform, Legionella, Giardia lamblia, cryptosporidium, viruses, turbidity) Disinfection by-products (Haloacetic acids, trihalomethanes, bromate, chlorite, others) Inorganic chemicals and metals (As, Pb, F, Chromium, nitrates, nitrites, Cd, Asbestos ) Organic chemicals (dioxin, PCBs, toluene, vinyl chloride ) Radionuclides (radium, uranium ) Lecture #1 Dave Reckhow 4

5 Cycling of Mercury ( mercury-environment) Common Environmental Engineering Terms Pollution prevention At source rather than at end-of-pipe Sustainable engineering Water/wastewater treatment technology Environmental remediation Contaminant removal from environmental media Lecture #1 Dave Reckhow 5

6 Some Basic Rules mass (g) =MW (g/mol) x n (Moles) Example: What is the number of moles of KCl (MW=74.45 g/mol) in g of KCl? n=mass/mw= /74.45= mol Molar concentration: C i (mol/l)=n i (mol) / Volume (L) In 1 L of water: C i =0.001/1=0.001 mol/l Mass concentration: C i (g/l)=mass i (g) / Volume (L) In 1 L of water: C i =0.001 g/l Some Basic Rules Dilution: C 1 V 1 =C 2 V 2 Example: You have a 12.0 M solution of hydrochloric acid (HCl) and your experiment requires ml of 8.0 M HCl. How much water and how much 12.0 M HCl should you use to make ml of 8.0 M HCl? How much HCl? 12V1= 8*150 V1= 8*150/12= 100 ml of HCl How much water? =50 ml of water Lecture #1 Dave Reckhow 6

7 Mass Balance Conservation of mass to account for material entering and leaving a system to analyze physical systems 1. Define you control volume 2. Choose the material of interest 3. Consider all possible sources (inputs) and sinks (exports) Typical mass balance Evaporation Precipitation Surface water Sediment Bottom Algae Lecture #1 Dave Reckhow 7

8 Basic Questions What is the stuff? Identify the species of interest How much stuff is there? Concentration Concentration: the amount of a substance per amount of media Common forms (assuming constant pressure): Mass balances of substance A in air: C A =Mass A / Volume Air Chemical reactions of substance A in air: [A]=Moles A / Volume Air Basic Questions How fast is the stuff entering and exiting a specified volume? Flow rate or Q Flow rate: the volume of fluid that passes through a given media per unit time Q (L 3 /T)= Volume / time = Area * velocity If we have 10 gallons of tap water in 10 minutes: Q=10 gal/10 min=1 gal/min Lecture #1 Dave Reckhow 8

9 Typical mass balance Example: N Evaporation Precipitation Q in C in Surface water Q out C out Sediment Accumulation= Σimports Σexports + Σsources Σsinks Bottom Algae =ΣCinQin-ΣCoutQout+S-kVC Lab Session #1 Objective: To measure volumetric flow rate (Q) and mean velocity (v) of a small stream Three methods: Floating markers Tracer-dilution Mechanical current meters Lecture #1 Dave Reckhow 9

10 Floating Markers Method A measure of the time it takes for an object to float a specified distance downstream, or a measure surface velocity (v surface ) Eq. 1,2 Eq. 3 Eq. 4 Tracer-Dilution Method (Instantaneous) A measure of the downstream concentration of a tracer (known volume and concentration) discharged/injected instantaneously (sudden/slug) upstream over time until the concentration reaches the background level. Calculating the discharge from the slug injection method involves integration, or calculating the area under the curve of concentration vs. time Tracer concentration (C) Time (t) Area Cb Lecture #1 Dave Reckhow 10

11 Mechanical Current Meters Method Swoffer meter: Based on stream velocity at a specific point (depth and width) for a specified time frame (in seconds). 0.6D 0.2D 0.8D Lab Session #1 Today: Make groups of 4. Read and understand the lab session handout for next week s lab exercise for all three methods. Day of: Expect to step into the stream (knee-depth at most) so wear appropriate clothing (flip-flops, shorts). Bring a notebook to record your data and take notes. Leave on time to reach Groff Park by 2:25 PM If you don t know the directions and/or need a ride, talk to your TA. Write-up Prepare a write up (1 per group) as per technical report handout and the lab handout (last couple of pages) Turn in your write-up at the beginning of the following lab session. You have a two-week period instead of the traditional one-week period. Lecture #1 Dave Reckhow 11

12 Next To next lecture Reading for next class: M&Z: Chapter 1 Hardin s Tragedy of the Commons Science, 13 Dec 1968 (pg 1243) Also in html David Reckhow CEE 370 L#1 23 Lecture #1 Dave Reckhow 12