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Enviromental treatment Laboratory sessions

CIVL375: WATER AND WASTEWATER TECHNOLOGY

LABORATORY SESSIONS
1. SAFETY
In order to avoid personal injuries or injuries to fellow students while performing
experiments in the laboratory, it is required that you read and understand the safety
handouts distributed in the CIVL270 course. The following points are just to refresh
your memory with some of the regulations mentioned.
1.1 Personal Protection
1. Wear safety glasses at all times in the laboratory.
2. Do not taste anything in the laboratory.
3. Never use mouth suction in filling pipettes.
4. Exercise great care in noting the odor of fumes.
5. Doors to laboratory rooms must remain open when working in the laboratory.
6. No one is to work alone in the laboratory without previous arrangement.
7. If you got foreign material in your eye, immediate washing with water only is
essential. Use an eye fountain at once. If you spill any chemical on yourself,
immediately wash with large amounts of water; then notify your instructor.
8. Do not use organic solvents to remove organic compounds from the skin; they
will spread the damage over a wider area. Solvents also tend to penetrate skin;
carrying other chemicals along. Soap and water are more effective.

9. Do not apply ointments to chemical or thermal burns. Use only cold water.
10. You must obtain medical attention for cuts, burns, inhalation of fumes, or any
other laboratory accident.
11. Know the locations of the emergency shower, the eye fountain, the fire
extinguishers and the first aid kit.
1.2 Handling of Chemicals
1. Handle all chemicals, and for that matter all glassware and equipment, with the
greatest care so as to protect yourself and others from injury, and to minimize
breakage.
2. Treat all liquids as extremely flammable, corrosive, and toxic unless you know
them to be otherwise.
3. Concentrated acids and bases are always added to water and not the reverse.
4. Addition of concentrated acids or bases should be slow enough that containers
remain cool.
5. Don’t talk to anyone who is pipetting or handling concentrated acids or bases.
6. Never add chemicals back to the stock reagent bottle after you have withdrawn the
chemical. If nontoxic and nonhazardous, dispose of the chemical in the sink
diluting with much water.
7. Never pipette liquids from the original storage bottle. Rather, transfer the liquid to
a beaker, and then pipette from the beaker.
1.3 Dealing with Samples
1. Unless you know the nature of the sample, assume all samples are contaminated.


2. Label all samples appropriately.
3. Wear disposable gloves when handling contaminated samples.
4. Wash hands thoroughly in hot, soapy water before leaving the laboratory.
1.4 Safe Laboratory Techniques
1. Read the experiment before coming into the lab.
2. Perform no unauthorized experiments.
3. Do not remove any chemical or equipment from the lab without permission.
4. When working with electrical equipment observe caution in handling loose wires.
5. Use hood facilities when odors and gases are expected from chemical reactions.
6. View reactions horizontally.
7. Be a good housekeeper.
8. Report unsafe practices.
2. QUALITY CONTROL
Water quality management decisions are based on the assumption that correct and
reasonably accurate and reliable data are available. Thus, sampling and analysis are
basic aspects of water quality management. Furthermore, quality assurance requires

that analytical results be subjected to statistical tests for the determination of the level
of accuracy and precision in the obtained data and to exclude any fault readings
(outliers). The purpose of this section is to review briefly sampling and preservation
techniques and to highlight the different methods commonly used for water analysis.
2.1 Sample Volume, Container, Preservation, and Holding Time
Sample volume: Sample volume depends on the analyte, the method of analysis, and
the number of times the sample is to be analyzed. Standard methods for the
examination of water and wastewater lists the minimum sample volume needed for
different analytes.
Sample container: The material that the sample container is composed of should be
selected so that it will not react with the constituents to be analyzed for. Plastic
containers are the best for sampling inorganic parameters. Glass and teflon containers
with teflon lined caps are suitable for organic analytes. Sterile plastic or glass
containers are needed for microbiological samples.
Preservation: The objective is to retard changes to the analyte that inevitably continue
after the sample is removed from the parent source. The changes that take place in a
sample are either chemical or biological. Methods of preservation are relatively
limited and are intended generally to (1) retard biological action; (2) retard hydrolysis
of chemical compounds and complexes; and (3) reduce volatility of constituents.
These methods are usually limited to pH control, chemical addition, refrigeration, and
freezing as shown in the table below. In summary, refrigeration at temperatures near
freezing or below is the best preservation technique available, but it is not applicable
to all types of samples.


Holding Time: This is the maximum period of time that the sample can be hold after
collection before it is analyzed for the analyte of interest. If the holding time is
exceeded, the integrity of the sample is not guaranteed.
2.2 Methods of Analysis
Analytical methods are often classified as being either classical or instrumental.
Classical methods are categorized as gravimetric or titrimetric. Gravimetric Methods
include determination of solids content, moisture content, etc., while titrimetric
methods are based on the determination of the volume or weight of standard reagent
required to react completely with the analyte under consideration. Applications to
titrimetric methods in this course include alkalinity, hardness, dissolved oxygen (in
the BOD test) and COD.
Instrumental analysis is based on detecting a signal produced by the analyte under
certain conditions. The signal could be electromagnetic radiation, electrical, mass-tocharge ratio, thermal, reaction rate, or radioactivity. An instrument for chemical
analysis is generally made up of four basic components, a signal generator, an input
transducer (detector), a processor, a readout device.
2.3 Calibration Curves
Typically, we will have a series of standards of known concentrations (X) and the
corresponding analytical signals (Y). The values of X (independent variable) are
considered constants and free from error, whereas the values of Y (dependent
variable) have random error associated with them. We are interested in being able to
predict a value of the dependent variable (Y) from a given value of the independent
variable (X). To do that, we perform a regression of Y on X to generate a calibration
curve.
The equation is then used to estimate X, the concentration, for any signal from the
instrument. However, the value of X predicted should not exceed the range used to
establish the calibration curve, because we cannot be certain of the position of the
extrapolated curve. It may not be linear at higher concentration. In this case, we have
two choices either to dilute the sample and analyze again or establish a new
calibration curve with a wider range.
Some instruments have the capability of a built-in calibration curve. In this case, the
instrument constructs a calibration curve form a set of tested standards by the user.
3. DATA SHEET
The class will be divided into groups to perform experiments and share data.
However, each student should have his/hers laboratory notebook. In the laboratory
notebook, student should record all data or information obtained from the laboratory
about the experiment. Notebooks are typically collected at the end of all laboratory
experiments for grading.
Organize your laboratory notebook in the following manner:


Cover:
First page:
Second page:
Third page:

Your name in the upper right corner.
Course number, course title, your name, and term of enrollment.
Table of contents (you will develop this throughout the course).
Begin with the first laboratory exercise.

Each laboratory exercise should be organized such that the first page shows the
laboratory exercise number and title and the date. Subsequent pages of that laboratory
exercise should contain: Preliminary calculations (if required), sample collection and
identification, equipment, results and calculations. At the end of each laboratory
exercise, a data sheet should be submitted and signed by the laboratory engineer.
Data sheets for the experiments will be distributed/posted on Blackboard.
4. LABORATORY REPORTS
Individual reporting is requested. Any student who did not perform a laboratory
exercise will be given half the grade of the report. Reports are due one week after
completion of the laboratory exercise. For details on the requirements, see the
distributed data sheet.
5. LABORATORY EXPERIMENTS
This laboratory contains 8 experiments. A brief description of each is given below
while details about each experiment are posted on Blackboard.
Exp1-Reactors:

This experiment is directed to evaluate the dispersion
coefficient of a dispersed plug-flow reactor.
Exp2-Settling:
The objective of this experiment is to measure type III and IV
settling of concentrated flocs. This type of settling occurs in
secondary clarifier after biological treatment. The sample that
will be used will be collected from the entrance to the
secondary clarifier at Zakher Wastewater Treatment Plant.
Exp3-Distillation:
This experiment is intended to illustrate the concept of
distillation and to verify the concept of mass balance.
Exp4-Coagulation: In this experiment, a coagulant will be sued to remove
suspended solids form solution. The sample that will be used is
either a synthetic sample or a real sample from a dam site in
UAE.
Exp5-Softening:
The use of lime and soda ash for removal of hardness is tested
here. The sample that will be used is a groundwater sample.
Exp6-Sorption:
Removal of organic contaminants by activated carbon will be
explored here. A synthetic sample that contains methylene blue
as the organic contaminant will be utilized.
Exp7-Ion exchange: Hardness removal will also be tested by the use of a cationexchange resin.
Exp8- Biological:
A batch aeration tank will be used in this experiment to
evaluate the removal of BOD from a wastewater sample
obtained from Zakher Wastewater Treatment Plant.



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