This document summarizes a student's lab experiment measuring turbidity in water samples. Turbidity is an indicator of water quality, measuring the cloudiness caused by suspended particles. The student tested tap water and bottled water from a lava company, finding turbidity levels of 2.4 NTU and 0.11 NTU respectively. Both results are within World Health Organization and EPA drinking water guidelines. Potential sources of error in turbidity measurement are discussed. The conclusion is that the water samples are suitable for drinking based on their turbidity levels.

1. University of Sulaimani
College of Engineering
Civil Engineering Department
(Water Supply and sanitary Lab)
Test No: 2
Test Name: Turbidity
Student Name: Raz Azad Abdullah
Group: A1
Date of the Test: 30-10-2019
Date of Submission: 13-11-2019

2. 2
Introduction:
Turbidity, a qualitative characteristic which is imparted by solids
obstructing the transmittance of light through a water sample, is an
important water quality indicator. Turbidity can be interpreted as a
measure of the relative clarity of water and often indicates the
presence of dispersed, suspended solids; particles not in true solution
such as silt, clay, algae and other microorganisms; organic matter and
other minute particles. Turbidity is not a direct measure of suspended
particles in water, but a measure of the scattering effect such particles
have on light.
Purpose of the Test:
In drinking water, turbidity can indicate the presence of high bacteria
levels, pathogens, or particles that can shelter harmful organisms from
disinfection processes. Therefore water treatment plants constantly
monitor turbidity levels to ensure that the water does not exceed safe
levels. Turbidity is also important in industrial processes or products
where particulates can be detrimental to the end use, or are vital
ingredients of the product. In either case, turbidity can be used as a
quality control measure to monitor the efficiency of the treatment or
manufacturing process.

3. 3
Materials and Equipment:
-Source of water
1-Tap water
2-lava company water (bottle)
-Equipment:
1-Turbidity Meter
2-small tubes contained with the meter for containment of the water
samples.
-Method of turbidity measurement:
 Nephelometric method.

4. 4
Procedure:
1. Ensure that the instrument has been standardized recently and that the
span controlhas not been changed since standardization; with the
instrument turn off. Check the mechanical zero setting.
2. Press the power switch and batt. Check. Switch and verify that the mater
indicates within the battery check area. If it does not recharge the battery
pack.
3. Press the appropriate range switch. Select the range that will exceed the
expected turbidity of the sample under test.
4. Place the focusing template into cell holder and adjust the zero control
for a reading of zero NTU. Remove the focusing template.
5. Fill a clean sample cell to the white line with the sample to the measured
and place it into the cell holder. Use the white dot on the sample cell to
orient the cell in the same position and each time. Cover the sample cell
with the light shield and allow the meter to stabilize. Read the turbidity
of the sample.
Data & Results:
Sample No. NTU Source of water
1 2.4 Tap water
2 0.11 Lava company water

5. 5
Discussion & Conclusion:
Turbid water contains particles or sediment that makes it dense or cloudy. Lab
testing equipment used to measure drinking water, wastewater treatment, and
water processing applications for turbidity is ideally done with turbidity process
instruments.
In this test we can notice that for the tap water the turbidity is measured to be
(2.4NTU) and for the other source is (0.11NTU)
By comparing it with the standards which are, worlds health organizations
recommends turbidity until (5NTU), which is ok and accepted to that range ,
and EPA drinking water standards limit turbidity to the max value (1NTU) but
any value to (5NTU) is also acceptable.
EPA recognized standard test method for static determination of turbidity below
5 NTU primarily for municipal drinking water and ultra-pure water.
There are some sources of interferences and errors that wed must be careful to
it:
 void samples containing air bubbles, coarsedebris, or floating
sediments—all of these can cause erroneous measurements
 For the highest accuracy, calibrate your turbidity meter with the
appropriate calibration standard in each measuring range
 Etched, scratched, or dirty sample vials scatter light and give inaccurate
readings; always use clean vials that have a protective case or extra-long
tubes to allow for handling outside the measuring area
 Wear gloves to avoid smudges or fingerprints on vial surface and to keep
the surface clean
 Take readings on smooth sturdy surfaces—vibration can cause errors in
your measurements.
We conclude that the results we obtained are ok by comparing it with
standards and they are in range, both samples are suitable for drinking
and domestic works.

6. 6
References:
1-Sainatary lab manual.
2-https://www.coleparmer.com/blog/2013/10/03/lab-equipment-
using-turbidity-process-instruments-to-test-water-quality/
3-https://www.slideshare.net/anasmaghayreh/turbidity-lab-7