laboratory exercises and field measurements in environmental engineering 1 water resources and...

Laboratory Exercises and F ield Measurements in Envir

onmental Engineering

1WATER RESOURCES AND ENVIRONMENTAL

ENGINEERING LABORATORY

By: Ali Torabi Haghighi

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Laboratory Exercises and Field Measurements in Environmental(488118S )

The Laboratory Exercises and Field measurement in Environmental Engineering course is composed of 5 different modules: Geotechnical engineering, Site investigation and field measurement; Hydraulics; Groundwater; and Water and wastewater treatment. It is strongly recommended that before undertaken this course the student should acquire basic knowledge in the fields of geotechnical engineering, hydraulics, ground water engineering, water and wastewater treatment processes. At the University of Oulu these knowledge is provided by the following courses:

• 488106A Basics in environmental geotechnics; • 488108S Groundwater engineering; • 488113S Hydraulics for environmental engineering;• 488110S Water and wastewater treatment;• 488115S Advanced environmental engineering.

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Schedule:

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Modules:

• Module1: Site investigation and field measurement

• Module2: Fluid mechanics and open channel hydraulics

• Module3: Ground water engineering

• Module4: Geotechnical and Geoenvironmental Engineering

• Module5: water and waste water engineering

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Module 2 : Fluid mechanics and open channel hydraulics

• Fluid mechanics contains (water discharge, Momentum equation, Bernoulli’s equation )

• Open channel hydraulics contains (Different methods for measuring flowrate, weirs, gates, Hydraulic jump and...)

• work with data logger • Tracer test

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Module 3: Ground water engineering

• Soil parameters (Hydraulic conductivity (K), specific yield (S), porosity (n) and PF )

• Darcy low and Groundwater flow• Contaminant transport

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Module 4: Geotechnical and Geoenvironmental Engineering

Geotechnical Tests

Soil classification

Sieving

Hydrometer

Etterberg Limits

Liquid limit

Plastic limitSoil

improvment Compaction

(proctor )

Soil streght Direct shear box

Cnosolidation Eodeometer

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Module 5: Water and waste water engineering

• Jar test experiment• Settling velocity• Limestone (CaCO3) filtration • Aeration• Determination of Fe, Cl-, Mn

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Module1: Site investigation and field measurement

• Work with GPS• Surveying and prepare a topography map• Soil sampeling• Water sampeling• Calculate water velocity and discharge

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Course assessment

• Participate in lectures and prepare the assignments (20 %)• Quiz (15%)

• Participate in lab and field activities(20 %)• Prepare report(%40)

You get points of report if you participate in field and lab activites and pass the quize

If you participate on more than 85% of course schedule, you can recieve 10 credit points when you collect sufficient points from all 5 modules

If you participate between 40-85 % of course you can recieve 5 credit points when you collect sufficient points from different modules(at least 3 modules)

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How to Write a Lab Report

• Lab reports are an essential part of all laboratory courses and usually a significant part of your grade.

• Title Page• Title• Introduction / Purpose• Materials• Methods• calculation• Results• Discussion or Analysis• Resources of error• Conclusions• Figures , Graphs and table• References

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Units of measurement

• A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity

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SI Vs. Imperial system

SI• The International System of Units (abbreviated SI

from the French Le Système International d'Unités) is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. It is the world's most widely used system of measurement, both in everyday commerce and in science. The older metric system included several groups of units. The SI was developed in 1960 from the old meter-kilogram-second system, rather than the centimeter-gram-second system, which, in turn, had a few variants. Because the SI is not static, units are created and definitions are modified through international agreement among many nations as the technology of measurement progresses, and as the precision of measurements improves.

Imperial System

• Imperial units or the imperial system is a system of units, first defined in the British Weights and Measures Act of 1824, later refined (until 1959) and reduced. The system came into official use across the British Empire. By the late 20th century most nations of the former empire had officially adopted the metric system as their main system of measurement.

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Prefix• A prefix may be added to a unit to produce a multiple of the original

unit. All multiples are integer powers of ten. For example, kilo- denotes a multiple of a thousand and mille- denotes a multiple of a thousandth; hence there are one thousand millimeters to the meter and one thousand meters to the kilometer. The prefixes are never combined: a millionth of a kilogram is a milligram not a micro kilogram

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Errors• Any measurement includes errors, we can never

find the true value, we can find the best estimate of the measured quantity.

• Types of Errors:1. Gross Errors (Mistakes): Large amounts, easy to find, must be

eliminated before adjustment.

2. Systematic errors: Follow a mathematical function, can usually be checked and adjusted, and tend to maintain same sign

3. Random Errors: remains after eliminating gross and systematic errors. Impossible to compute or eliminate. They follow the probability laws, so they can be adjusted Their signs are not constant. Present in all surveying measurements.

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Mistake

• Mistakes. Entirely distinct from errors, in the sense heretofore used, are those inaccuracies which are due purely to carelessness, and which should properly be

called mistakes.

They consist in such blunders as reading the wrong number on the scale, reading one number and putting another down in the notes, making a miscount in timing and lost some steps

Mistakes are usually easily detected, and there is no remedy except careful checking. When measurements are made more than once the checking is a simple matter.

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Random vs. Systematic Error

• Random errors:• in experimental

measurements are caused by unknown and unpredictable changes in the experiment. These changes may occur in the measuring instruments or in the environmental conditions.

• Systematic errors in experimental observations usually come from the measuring instruments. They may occur because: there is something wrong with the instrument or its data handling system, or because the instrument is wrongly used by the experimenter.

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Example of systematic error

• You want measure a 425 meters length with a 50 meters measuring tape.

This device has +10 cm systematic errorIt means in each times measuring you record 50 meters but in real you measure 49.90 meter finally you have 425+8.5 *.10meters (425.85) in your record inset of 425 meters

In real49.90

But museaure

49.90 49.9049.90 49.90 49.90 49.9049.90 25.8

50.00 50.00 50.00 50.00 50.00 50.0050.00 50.00 25.8517

425.8517 425.0- = .8517 meters error

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Precision vs. Accuracy

• Precision:"The precision of a measurement refers to how close to one another these repeated measurements are.“

• Accuracy:"The accuracy of a series of measurements is the closeness of their average value to a true value."

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Probability• Error analysis involve random errors only.• Random errors occurrence is governed by the

probability laws, as any random phenomena.• The most probable value of a single quantity

observed many times under the same condition is the mean

M = Oi

n

Residuals: the difference between any observation and it’s most probable value: vi = M - Oi

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Error Distribution• Random errors are randomly distributed, a bell shape

distribution that is approximated by the probability curve.• General Laws of Probability:

– small errors occur more often than large ones– Positive and negative errors of the same size happen

with equal frequency, they are equally probable. That is why the mean is the most probable value.

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Measures of Precision• standard deviation is the most frequently used measure of precision. The less

precise the observations are, the larger the standard deviation becomes

• The standard deviation is the inflection point of the curve, it represents how much the observations are close to each other.

• It has a probability of 68.27. That means 68.27 of the observations will be in the range of

2

1v

n

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CALIBRATION

• Calibration is a comparison between measurements - one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device.

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Thanks