CEEB 221 INTRODUCTION TO ENVIRONMENTAL ENGINEERING LABORATORYLABORATORY EXPERIMENT NO. 5TURBIDITY MEASUREMENT

SECTION: 05

NAMEID

MUHAMMAD FIKRIL AZIM BIN ABDUL SANICE094946

AMMAR BIN MD DENICE095821

JULIANA BINTI RAZALICE095999

DATE OF LABORATORY SESSION : 27 NOVEMBER 2015DATE OF REPORT SUBMISSION : 4 NOVEMBER 2015LAB INSTRUCTOR : ENCIK NAZIRUL MUBIN BIN ZAHARI

TABLE OF CONTENTCONTENT PAGE

Table of Content2

Summary/Abstract3

Introduction & Objective3

Apparatus and Equipment 4

Procedure4

Results & Calculations 5

Discussion6

Conclusion6

References6

Appendix7-8

Summary/AbstractIn the past 10 years, the analysis ofturbidityhas become far more than just a measure of water clarity. Now, low level turbidity analysis is becoming the method of choice for protection against emerging pathogens such as Cryptosporidium and Giardia. By assuring proper water filtration, risks from a variety of undesirable contaminants in our nations water supplies can be reduced.

IntroductionTurbidity of water is caused by the presence of colloids and suspended solids. Colloids are solids with sizes between suspended solids and dissolved solids. There are two types of colloids: hydrophilic and hydrophobic. The hydrophilic have affinity for water, while hydrophobic dislike water. It is easier to remove hydrophobic colloids. A water sample might have high colour but without any turbidity e.g. coke.The earlier measurement of turbidity is done by a circular disc with black and white painted over it. The turbidity is measured by the depth of the disk in water till it cant be seen. The shallower the reading indicates the higher the turbidity. After that, a new system was develop by placing a candle beside the sample, known as Jackson candle. The disappearance of the shadow of the candle indicates the turbidity of that sample. The current method based on standard solution make up with formazin. The turbidity yield by one mg/l of formazin concentration is known as 1 turbidity unit. This method is known as nephelometric method, hence the turbidity is known as nephelometric turbidity unit, or NTU. A series of standard solutions are made up and measure their respond in a turbidity meter. A calibration graph of respond verses formazin concentration is used to measure samples turbidity.There are two types of turbiditimeter in the markets, viz. portable and benchtop. They are very handy to use. The portable is useful on site. The benchtop however yields a better result as it has longer light path and accuracy.

Objective

To determine the turbidity of a sample from the water in the pond in front of BD.

ApparatusThe list of apparatus include: Turbiditimeter Sample vials

ProcedureA few are given to be measured.1. The sample is poured into the vials provided. The vials are dried and placed into the turbiditimeter. 1. The turbidity readings were recorded.

Results and CalculationsPlace of water collectedSampleBench Top TurbidimeterPortable Turbidimeter

Pond in front of BE11.081.59

Murni Apartment Toilet21.761.40

BD Toilet30.460.51

Observation

1. Bench top turbiditimeter and portable turbiditimeter portray slightly different readings.2. There are some visible particles inside the water samples inside the vials such as grass.3. All traces of fingerprints must be wiped off thoroughly from the side of the vials.4. The vials must be dried first before pouring the water samples inside.5. The clearer the water sample, the lower the value shown on both bench top and portable turbiditimeter.

DiscussionIn this turbidity measurement experiment, there are a lot of obstacles which can occur to avoid us from getting the accurate data. Some of the obstacles can be prevented and some might be unable to be prevented. The turbiditimeters are very sensitive to be handled. The errors that may influence our results are fingerprints on the vials, the vials are not fully dried and contaminations of large dirty particles of the sample inside the vials such as grass and sand. Besides that, to overcome this errors we have to wipe the vials fully until dry before pouring the sample inside, at the same time we have to make sure there is no any large dirty particles in the sample inside the vials, before placing the vials in the turbiditimeter we have to wipe the outer surface of the vials to avoid fingerprints. We have to place it by holding the cover of the vials. Different sample we have to use different vials to be accurate. Then, this may help us to increase the accuracy of our results but anyhow they might be some errors due to nature that cannot be overcome by us. The accuracy of the result will be higher if and only if the difference between the bench top turbiditimeter and portable turbiditimeter are less.

ConclusionAfter conducting this experiment, we can clearly see that the bench top & portable turbidimeter showed different readings. The highest value shown by bench top turbiditimeter is 1.76 NTU, collected from the Murni Apartments Toilet meanwhile the highest value shown by portable turbiditimeter is 1.59 NTU which was collected at the pond in front of the BD building. On the other hand, the lowest value shown by bench top turbiditimeter is 0.46 NTU from the BD toilet and the lowest value shown by portable turbiditimeter is 0.51 NTU, collected at BD toilet too.

Theoretically, portable turbiditimeter and bench top turbiditimeter should have showed the same results but both have different focuses because portable turbiditimeter is useful on site while bench top turbiditimeter is designed to produce better results.

What can be concluded is that, if a sample has a darker colour and contains colloids or suspended soils, it can be said to have a high turbidity.

ReferencesLaboratory Manual, CEEB 221 Introduction to Environmental Engineering Laboratory, 1st draft October 2013 by CKH.

Appendix

8