edited laboratory manual 2013-2014

8/11/2019 Edited Laboratory Manual 2013-2014

1/38

CVNG 3007ENVIRONMENTAL ENGINEERING 1

LABORATORY MANUAL2014 2015

The Analysis of Water and Wastewater

Prepared by: Althea Richardson (CET)Department of Civil and Environmental Engineering

The University of the West Indies- St Augustine Campus


2/38

2

CONTENTS

Introduction

Safety Guidelines

Lab report format

Activity 1 -Lab - Analysis of water

Experiment 1 - Bacteriological AnalysisExperiment 2 - Jar TestExperiment 3 - Source Determination

pHTotal/Free Chlorine Residual

ChlorideHardnessAlkalinity

Activity 2 -Lab - Analysis of Wastewater

Test 1 - Dissolved Oxygen (DO) - Titration MethodTest 2 - Biochemical Oxygen Demand (BOD)Test 3 - Total Suspended Solids (TSS)Test 4 - Settleable Solids (SS)Test 5 - pH

Activity 3 -Field Trip/ Visit

1. Beetham Wastewater Treatment Plant2. Caroni Arena Water Treatment Plant


3/38

3

INTRODUCTION

Water, wastewater... what's the difference?

Environmental professionals toss around the terms " water" and " wastewater" every day,without a doubt as to their meanings. Outside of the profession however, differences in thetwo terms might not be so clear.

A better term for what we usually call "water" is "drinking water or potable water. It is thewater that comes out of the tap. It is water that is safe to drink and also used for bathing,cooking, and washing.

Drinking water starts out as lake/dam/reservoir water, river water, or groundwater. Drinkingwater providers like WASA draw "raw water" from one of those sources and pump it to afacility called a "water treatment plant" where the raw water maybe chemically treated and

then routed through a series of settling tanks and filters to remove particles so small, they aremeasured in millionths of an inch. Chlorine is added, and the finished water is ready to drink.A large network of pumps, storage tanks and pipes then moves the drinking water into ourhomes.

Wastewater is what others often call "sewage". It is essentially what is produced when drinkingwater is used indoors. The drinking water that was used to bathe, cook, or flush becomeswastewater when it falls through the drain.

Wastewater treatment has its own large network of pipes to collect it from homes andbusinesses and convey it to a facility for treatment. These facilities, called "wastewatertreatment plants" operate much differently from water treatment plants. Wastewatertreatment plants first utilize a series of screening and settling processes to remove large,inorganic solids. Next, natural biological processes are used to break down and remove organicmatter. More settling is used to remove the natural bacteria which have consumed the organicmatter. Finally, the cleansed water is disinfected. What came into the treatment facility aspolluted water (wastewater) has now been purified to natural stream water quality. Thereclaimed water is released into a waterway.The reasons for treating drinking water are very different from those for treating wastewaterand there are basic, essential differences between drinking water treatment/distributionsystems and wastewater collection/treatment systems.

Treating water and wastewater to make it acceptable requires frequent testing and monitoringof the process to ensure that a high quality end product is obtained and maintained. Accurateand reliable laboratory analyses are absolutely necessary for quality control and to provide abasis for making operational changes to treatment processes.


4/38

4

Objectives of the laboratory Exercises

These labs are designed to familiarize you, the environmental engineering student, with thecommon Laboratory tests and the associated analytical skills that are used to monitorenvironmental systems and water and wastewater treatment processes. They will also be usedto illustrate some fundamental water and wastewater engineering concepts.

Activities

You will be expected to complete 2 laboratory sessions and a field visit to a Water Treatmentand Wastewater Treatment Plant.

ALL students must attend ALL classes and submit reports (3) for all activities. Your lab markswill contribute to a percentage of your coursework marks.

To facilitate hands on and full student participation the class has been divided into groups A, B& C. During the laboratory exercises each group will be further divided into sub-groups of 4-5students

Students should familiarize themselves with the laboratory schedule and other informationposted on the departmental notice board from time to time.

You are also expected to read the laboratory manual and try to conceptualize the exercisesbefore coming to labs.


5/38

5

GENERAL LABORATORY SAFETY

Safety is the collective responsibility of all but you are ultimately responsible for your ownsafety. The more prepared for labs you are the safer you will be.

Accidents often result from an indifferent attitude, failure to use common sense, or failure tofollow instructions. Each student should be aware of what the other students are doingbecause all can be victims of one individual's mistake. Should an accident occur, there may besignificant injury to the persons involved or anyone in the vicinity. Do not hesitate to point outto other students that they are engaging in unsafe practices or operations. If necessary, make areport to the instructor.

The most common accidents that occur in chemical laboratories are:- Cuts from broken glassware or damaged equipment. Burns from chemicals or hot surfaces.

Burns and injuries from explosions. Skin and eye irritation caused by contact with chemicals or samples Inhalation of toxic fumes.

In environmental (water) chemistry, additional safety concerns are associated with the natureand collection of the samples tested in the laboratory exercises and while most of the chemicalsused at this level may not be extremely hazardous, due care and attention MUST be exercisedat all times.

A lot of emphasis has been placed on making the lab exercises as safe as possible and the labpersonnel will take the necessary precautions to prevent or reduce the occurrence of accidents.The safety rules given below and the additional instructions for each laboratory exercise should,at all times, be adhered to as closely as possible. Additionally, in order to ensure a successfuloutcome, the laboratory personnel will give specific instructions, during each experiment,which you should follow

SAFETY RULES FOR THE ENVIRONMENTAL LABORATORY

Safety Equipment: on entering the laboratory please determine the location of the EyeWash Station, Safety Shower and Exit doors in the event it becomes necessary to usethem.

Hygiene: You will be exposed to sewage which could be hazardous. Handling your pens,calculators, books, bags, etc. with contaminated gloves will contaminate those items.Every effort will be made to reduce your level of exposure.


6/38

6

Use the disposable gloves provided correctly. Before use, ensure that there are no cracksor small holes in the gloves

Be aware that if a chemical diffuses through a glove and it is held against your hand youmay be more exposed than if the glove had not been worn.

Remove gloves before leaving the lab and before handling telephones, doorknobs, writinginstruments, laptops and laboratory notebooks in order to prevent the unintentionalspread of hazardous materials.

Dispose of used gloves in the bins provided . Do not leave them lying around on the desktop.

Dress appropriately for labs . Although Lab coats or aprons are not usually required,clothing worn to labs should offer protection from splashes and spills and should be easy to

remove in the event of an accident.

Wear old, inexpensive clothes (T shirts and jeans), safety shoes and sneakers or closedtoe shoes

The wearing of short pants or skirts, sleeveless shirts or jerseys, tank tops, short T shirts,open toed shoes (sandals, clogs and slippers), inappropriate fabric and jewelry will not bepermitted in the laboratory and on field trips.

SAFETY GLASSES during the labs is allowed but not absolutely necessary.

If you must wear contact lenses, you will be required to also wear fitted goggles

Tie long hair or braids back or up to prevent interference with your performance or that ofothers.

Students WILL NOT be allowed to eat, drink or chew gum while in the lab .

ASK the laboratory personnel for HELP to refill and to dispose of unused (waste) reagents.

Immediately report ALL spills and accidents to the laboratory personnel no matter how

small or insignificant they might appear to you.

Housekeeping: De-clutter work areas. Books, bags or folders will not be allowed on thebench tops. Tidy your work area before leaving the lab . This will avoid you leavingimportant documents and valuables behind.

Before leaving the lab, wash hands and arms up to elbows, even if gloves were worn.


7/38

7

FIELD TRIP SAFETY RULES

Your field trip is an academic exercise and must be treated as such

While on the field trip adhere to ALL the safety requirements and comply with ALLinstructions given by the plant personnel .

gear up appropriately

a. Sturdy close-toed shoes or sneakers

b. Long Pants

c. Long-sleeved shirt or weather-appropriate outer wear

d. Hat

e. Sunscreen

f. Personal medication

g. Water and at least a healthy snack

h. Field notebook and writing utensil

Stay within sight of the field aide

Do not remove anything from the sight unless directed to, leave the area better than youfound it

Be prepared to treat each other with respect and work cooperatively to get the job done

Do not use electronic devices unless the facilitators of the trip give their approval.


8/38

8

GUIDELINES FOR THE LAB REPORTS

1. Three (3) reports should be submitted one (1) for each lab and one (1) for the field trip.

2. Reports should be no more than 20 pages (exclusive of the first page), typed and allpages numbered.

3. DO NOT SUBMIT YOUR CVNG 3007 REPORT IN A (MANILA OR PLASTIC) FOLDER. Attach acover (Title) page to your report *, staple all the pages together and submit.

4. REPORTS ARE DUE EXACTLY Two weeks AFTER THE LAB.They should be handed to thepersonnel in the Environmental Laboratory only. Five (5) marks would be deducted afterthe first week outstanding and each week thereafter.

Lab Report format

* Cover (Title) page

A special cover page must be provided for each laboratory report.Clearly print the following on the cover.

lab title; course name and code; your name and ID number; names ofyour group members; date performed and date submitted; a list of itemsincluded in the report with the number of marks allocated for each item( the cover will also be used as a grade sheet). [2]

Abstract A short (one paragraph) summary of the entire report. [2]

Objectives State the objectives of the exercise. [2]

Introduction Explain why the particular tests were done. [3]

TheoryBriefly summarize the relevant supporting theory and applications. Thismay require you to restate or repeat information given in the laboratorymanual. Properly cite all information used. [3]

ExperimentalProcedure,

Methodology

Normally in this section you should describe the apparatus used; how itwas configured; how measurements were made and how the data was

recorded and analyzed.In this instance you are required to record ONLY the changes that weremade to the procedure given in the laboratory manual . [3]

Observations andResults

Report what you observed or measured in the experiments. Wherenecessary, show your sample calculations. Use tables, graphs anddrawings to present your results.


9/38


10/38

10

ACTIVITY 1

Water Analysis

INTRODUCTION

These experiments will allow you to perform some of the important physical and chemicalanalyses associated with the assessment of potable water quality, in accordance with WaterQuality Standards (WHO/EPA). It will also introduce you to the water treatment process.

Water Treatment Flow Chart

Objectives of this ActivityThe water lab will:

Introduce you to the common parameters and tests used to classify water;Provide you with experience in analyzing results obtained from laboratory tests;Illustrate the shortcomings of some laboratory tests;Demonstrate the standard procedures/methods, tools, apparatus and equipment used inan Environmental Laboratory

Learning OutcomesAt the end of this exercise the student will be able to:

Identify the some common apparatus used to conduct laboratory experiments; Observe laboratory safety precautions; Perform experiments in accordance with a written laboratory procedure; Obtain and tabulate readings and measurements with minimum error; Manipulate water quality data and use the results to infer water quality; Explain the processes used to treat and obtain potable water from differences sources.


11/38


12/38

12

Table 1. Acceptable coliform standards (colonies/100mLwater sample)

Drinking water 1 TCSwimming (pools) 200 FC

Boating (lakes etc.) 1000 FCTreated sewage effluent should not exceed 200 FC

TC Total Coliform FC Faecal Coliform

Principle of the MF method for total and faecal coliforms

The membrane-filtration method gives a direct colony count for a sample taken from a given

body of water. A measured volume of sample is filtered through a cellulose membrane filter ofpore size 0.45 micron. The microorganisms present in the sample are retained on the filter.The filter is then placed in a sterile Petri dish with the appropriate growth media- either M-Endo agar (for Total Coliform) or MFC agar (for fecal coliforms). The Petri dish is then incubatedfor at least 16 hrs at 35.5 oC (M-endo) and 44.5 oC (MFC). The appropriate conditions(temperature, moisture and time) will encourage the growth of the desired organism whilesuppressing the growth of all others. Each growth cell develops into a separate colony, whichcan be identified by its characteristic color, observed directly with the naked eye and counted.The results are calculated to give the true coliform population in 100mL of sample.

At times the degree of pollution in a water sample makes it difficult to accurately determine theactual number of organisms present. In that case, the sample size may need to be as little asone millionth of a milliliter. A serial dilution technique (shown below) is used to ensure that thenumber of colonies on the membrane filter does not exceed 20-80 colonies. In serial dilutionsuccessive volumes of sample are further diluted until the desired volumes of the test sampleare obtained.

MaterialMembrane filters (0.45 um) Petri dishes, with growth media - (MFC and M-Endo) Graduated cylinders -100mL

Dilution water Alcohol burnerVacuum pump with filtration apparatusIncubator @ 35 o C - for Total Coliform ;Water bath @ 44 o C for Fecal ColiformPlastic bagsTransfer forceps


13/38

13

SAMPLES

The following samples are provided for THIS TEST ONLY1. Sample A- Water from the tap in the laboratory2. Sample B - River water treated with household bleach

3. Sample C - River water

The serial dilution procedure should be performed on sample C only

SERIAL DILUTION PROCEDURE

USE A CLEAN I mL PIPET for each dilutionPut 1mL sample C into dilution bottle 1- (1/100 dilution)Put 1mL from bottle 1 into dilution bottle 2 - (0.01/100 dilution)Put 1mL from bottle 2 into dilution bottle 3 - (0.0001/100 dilution)

Test samples using the following order

1. Sample A - 100 mL2. Sample B - 25 mL and 50mL3. Sample C - bottle 3 - 10 mL

Bottle 2 - 1 mL and 10 mLBottle 1 - 1 mL and 10 mL

TEST PROCEDURE

Total Coliform Test1. Set up the membrane filter assembly as demonstrated2. Insert the membrane filter ( grid side up ) using the forceps.3. Shake the sample to be tested vigorously; then use either the measuring cylinder or a

pipette to measure the volume of sample to be tested (based on the volume required)4. Use a pipette to measure 1mL or 10mL. Put the pipetted volume () in the cylinder. Fill the

cylinder with the sterile water provided. Pour contents of cylinder into filter funnel andsuction.

5. Rinse the cylinder and the sides of the funnel with approx. 50 mL of the sterile dilutionwater.

6. Suction the membrane filter until dry, then using forceps, immediately transfer the filterpaper to a labeled Petri dish prepared with M-Endo media (identified).7. Incubate the inverted petri dish at 35 oC for 16-24 hours.8. Remove the Petri dish from the incubator after 16-24 hrs and Count only those colonies

which have a green-gold metallic sheen.9. Report the number of colonies for 100 mL of sample (see calculations) .


14/38

14

Fecal Coliform Test 1. Repeat steps 1 to 5 above.2. Transfer the membrane filter to a Petri dish with MFC media (as identified)3. Enclose the Petri dish in a waterproof (plastic) bag and seal the bag using the bag sealer.4. Secure the sealed bag with dishes inverted in the rack provided then submerge the rack in

the water bath to incubate at 44o

C for 16-24 hours.5. After the incubation period of 16 to 24 hours, remove the Petri dishes from the water bath

and carefully count only the blue colonies using either a magnifying glass or the unaidedeye .

6. Calculate and report the colony count for 100 mL of sample using the same calculations asbefore

RESULTS - COLONY COUNTING

After incubation, there may be a growth of micro-organism, if present in the sample, on thesurface of the MF. The fecal coliform colonies will appear blue in color, while non-fecal coliformcolonies will appear gray or cream colored. The total coliforms will appear as metallic greencolonies. The colonies can be clearly seen, discerned and counted with the naked eye.

When counting the colonies, the entire surface of the filter should be scanned using a 10x -15xbinocular, wide field dissecting microscope. Colonies may be counted by scanning across onerow and back across the next, etc. This should ensure that all areas of the filter are observed.

The desired range of colonies for the most valid fecal coliform determination is 20 to 60colonies per filter. If multiple sample dilutions are used for the test, counts for each filter mustbe recorded on the laboratory data sheet.

NOTE: Filters which show a massive growth over the entire surface of filter with no individuallyidentifiable colonies should be recorded as TNTC (too numerous to count).

Calculations

Coliform colonies for 100 ml of sample = 100Xfiltered sampleof volume

counted coloniesof #


15/38

15

Experiment 2 - Jar Test

Colloidal particles in water cause significant turbidity whichis measured in Nephelometric Turbidity Units (NTU).Turbidity describes the insoluble (colloidal) particles, whichimpede the passage of light through water (see figure). Thisvalue is used to quantify the degree to which light travelingthrough a water column is scattered by the suspendedorganic matter (including algae) and inorganic particles.Turbidity in excess of 5 NTU is noticeable to the consumerand is usually unacceptable.

A jar test simulates the coagulation, flocculation and sedimentation processes that encouragethe removal of suspended colloids and organic matter which can lead to turbidity, odor andtaste problems.

Jar testing is a common laboratory procedure used to determine the optimum operatingconditions for water or wastewater treatment. The test allows adjustments in pH, variations incoagulant or polymer dose, alternating mixing speeds, or testing of different coagulant orpolymer types, on a small scale in order to predict the functioning of a l arge scale treatmentoperation.

You are provided with a sample of untreated river water to be used for the Jar Test.

Procedure1. Put 500 mL of the river water sample provided, in each of six (6) 1L beakers.2. Calculate the appropriate volumes of stock (5000 mg/L) solution required to give

dosages of 10, 20, 40, 60, 50 and 70 mg/L. (subject to change during class)3. Add the calculated volumes of the stock alum provided to each of the six (6) beakers

while mixing at 100 rpm.4. Continue mixing at 100 rpm for an additional 1 min. after the addition of the alum

solution5. Reduce the speed (without stopping the process) to 20 rpm and continue mixing for 10

min.6. Compare the floc sizes and characteristics of formation in each beaker.

7. Stop mixing and allow the contents of the beakers to settle for 10 min.8. Remove the supernatant (liquid at the top) from each beaker without disturbing thesettled floc

9. Measure the turbidity and pH of each supernatant. 10. Use the final turbidity and pH measurements to determine the optimum coagulant

dose .


16/38

16

Apparatus/ReagentsJar test / flocculation apparatus completeAluminum Sulphate SolutionTurbidimeterSample cells, lens tissue

Distilled water

Turbidity measurement

Procedure1. Gently pour the sample into a clean sample cell up to the measurement line (approx. 30

mLs)2. Cap and wipe the cell, using tissue paper, while holding by the cap provided,3. Place the cell in the cell compartment of the Turbidimeter , close the lid.4. Allow the reading to stabilize (approx. 1-2 mins). Read and record the turbidity.5. Repeat the procedure for each sample.

Experiment 3 Source Determination

A source determination is very often used by the WASA to determine the source or origins of awater leak or unidentified body of water.

For this test you are provided with three (3) treated water samples, each taken from adifferent source . Use the following tests to determine the source of each sample.

Test 1. pH

pH is the measure of hydrogen ion activity in a given matrix. Itindicates the nature (acidic, alkaline and neutral) of the sampleand it is used to determine the possible presence of contaminantssuch as industrial or chemical wastes in water supplies.Two methods can be used to measure pH.

1. Visual (comparative) using pH strips and2. Electrometric using a calibrated pH meter with an

electrode.

Use the visual method to determine the pH of the 3 samples


17/38

17

MaterialspH papersCalibrated pH meter with electrodes100 mL beakers

Distilled water

ProcedureImmerse the paper in the sample and remove it immediately. Determine the pH bycomparing the color of the paper to the scale of colors printed on the packet as shown in thefigure.Record the value of the matched pH value.

Test 2. Chlorine ResidualChlorination of water supplies is done primarily to destroy or deactivate disease-producingmicroorganisms. After chlorine disinfection of a water supply, the Residual chlorine is thechlorine, which remains once the Chlorine Demand has been satisfied. A test for residualchlorine will measure the amount of chlorine available in the water supply to provide long-termdisinfection.

Determine the residual chlorine levels of the water samples provided.

Apparatus/ReagentsHACH Colorimeter + 10 mL tubesDPD reagent packets for Total and Free Residual chlorine

Procedure1. Fill two 10 ml cells /tubes to the 5ml mark with sample2. Add the contents of one DPD Free chlorine packet to one tube and the contents of one

DPD Total Chlorine packet the other tube.3. Cap and shake both tubes for 30 seconds4. For Free residual chlorine , wipe excess liquid and fingerprints from the outside of the

tube and put it in the cell holder of the HACH colorimeter, one minute after adding the

DPD.5. Cover with the instrument cap and press read/ enter the instrument will sho w ------

followed by the Free Residual Chlorine results in mg/l (ppm)6. For Total Chlorine , wait 3-6 minutes after adding the DPD reagent. Wipe excess liquid

and fingerprints from the sample cell.7. Repeat step 5.8. Record the Total Residual Chlorine in mg/L (ppm)9. Repeat procedure for all 3 samples


18/38

18

Test 3. Hardness

Water is usually considered to be hard when a considerable amount of soap is required toproduce lather. Generally, hard water is as satisfactory for human consumption as soft waters.Hardness is an important factor in industry because of the potential to form scale in boilers,water heaters, and distribution systems. The hardness of waters varies considerably fromsource to source and excess hardness can usually be removed by a combination of chemicaland physical treatment of the water.

Determine the Hardness of the water samples provided.

Apparatus/ReagentsBurette, pipettes Erichrome black T indicator125 ml conical flasks Ammonia buffer25 ml measuring cylinder EDTA titrant

Distilled water

Procedure N.B This titration should be completed within 5mins after adding the indicator.

1. Fill the burette with the EDTA titrant.2. Measure 25 mLs of the sample. Transfer volume to a conical flask.3. Add 1 mL buffer solution, 5 drops of the indicator and swirl flask to mix.4. Titrate from a purple to the first permanent blue end point.5. Record titre values.6. Repeat tests to ensure the accuracy of your results.7. Repeat the procedure for all samples.

Calculation

Hardness as mg CaCO 3/L =testedsample vol.of

1000 xvalueTitre

Test 4. Alkalinity

Alkalinity is defined as the capacity of water to neutralize an acid. Although many substances inwater may contribute to the alkalinity, the major contributors to alkalinity in natural waters arehydroxides, carbonates and bicarbonates. Many of the chemicals used in treating water cancause a change in its alkalinity, but the most pronounced changes are caused by coagulants,water softening chemicals, lime and sodium carbonate. Alkalinity measurements are used tocontrol water and wastewater treatment processes.


19/38

19

Total alkalinity (T) and phenolphthalein alkalinity (P) are defined as follows:

T = (HCO3) + (CO32) + (OH)

P = (CO32) + (OH)

T and P are respective alkalinity concentrations expressed as mg/L as CaCO 3. The titrationresults can be used to calculate the concentration as mg/L CaCO 3 of the different forms ofalkalinity using the following table

Table 2: Alkalinity formsResult ofTitration

Hydroxide(OH)

Carbonate( CO3

2)Bicarbonate

( HCO3-)

P = 0 0 0 T2p < T 0 2P T-2P2p = T 0 2P 0

2p > T 2p - T 2(T-P) 0P = T P 0 0

Apparatus/Reagents250 ml conical flasks Screened Methyl Orange burette, pipettes phenolphthalein indicators 100 ml measuring cylinder 0.02N Sulphuric acid Distilled water Sodium Thiosulphate solution

Procedure 1. Fill the burette with 0.02N sulphuric acid.2. Measure 100 ml of the water sample. Transfer volume to a conical flask.3. Add 2 drops of the sodium thiosulphate solution to the sample. This removes any

residual chlorine in the sample which would interfere with indicator response.4. Add 5 drops of phenolphthalein indicator.5. If a pink colour develops titrate slowly (add acid from the burette to the sample) until

the sample becomes colorless.6. Record the volume of acid used7. If no pink colour develops continue with (8)8. Add 3 drops of screened methyl orange indicator to the same sample

9. Titrate slowly until the first permanent colour change - green to gray - appears.10. Record all titer values and repeat procedure.

Calculations

Alkalinity (Tor P) mg CaCO 3 /L =testedsampleVol.of

50000X0.02Xvaluetitre


20/38

20

Test 5. Chloride

Chlorides ions in natural waters can be attributed to the dissolution of salt deposits, dischargesof effluents from chemical industries, oil well operations and sea water intrusion in coastalareas. Each of these sources may result in local contamination of both surface water andground water. A chloride concentration of 250mg/L may cause a salty taste to be detectable inwater depending on the predominant ions present. High chloride content may harm metallicpipes and structures as well as plants

Apparatus/ ReagentsBurette, pipettes Diphenyl carbazone indicator 125 ml conical flasks Nitric Acid 25 ml measuring cylinder Mercuric nitrate titrant Distilled water

Procedure1. Fill the burette with the Mercuric Nitrate titrant2. Measure 25mls of the sample. Transfer volume to a conical flask.3. Add 5 drops of indicator and swirl flask to mix4. Add 2 mls of Nitric acid, swirl flask again to mix5. Titrate from a light yellow to a permanent deep purple end point.6. Record titer values7. Repeat to ensure the accuracy of your results8. Repeat the procedure for all samples

Calculation


21/38

21

Discussion

Interpret all your results and include the following -: A brief description of the process used to treat water from each source (ground, surface,

and sea) to make it potable. Source identification of each of the source determination samples provided with

justification for your choices. An indication of whether the water samples are bacteriologically safe or unsafe for

drinking. Refer to and cite the appropriate Water Quality Standards. A brief discussion of each stage of the jar test procedure. Sources of error for all tests.

General Questions

1. Using the information provided in Table 2, determine the different forms (T, P, HCO 3,CO3

2, and OH) of alkalinity in the three (3) water samples.

2. Provide a rationale for testing water supplies for coliform bacteria and show how youwould obtain 0.00001 mL of a very contaminated wastewater sample.

3. What is the Water quality Index WQI? Read the fecal coliform index value (Q fecalcoliform) off the graph of Q vs. fecal coliform concentration.

4. List the negative environmental impacts of high turbidity in waters and describe theprocess used to remove high turbidity from river (surface) water in order to make itpotable?

5. Discuss the similarities and differences of the jar test plots shown on page 30 below to asimilar plot for your jar test results. Determine and indicate the optimal alum dose forall three plots.


22/38

22

ACTIVITY 2

Wastewater Analysis

INTRODUCTION

Wastewater is used water which has been adversely affected in quality by human influence. Itoften includes substances such as fecal waste, food, oils, soap/ detergents and toxic chemicals.There are several types of wastewater domestic, industrial, agricultural, process, institutional.Sewage is wastewater which is contaminated with feces and or urine but the term is often usedto also describe wastewater.

Municipal wastewater is usually conveyed in a combined sewer and treated at a wastewatertreatment plant or in a (on site) septic tank system. The treated wastewater is discharged into a

receiving water body.

In most cases the treatment process is specifically designed to treat a particular type ofwastewater e.g domestic wastewater is readily treatable in a municipal wastewater treatmentplant using conventional methods whereas it may be difficult to use a similar process to treatindustrial wastewater, which may contain high percentages of toxic chemicals, organicmaterials and solid residues.

Storm water or run-off is another type of wastewater which will usually go into a domesticwastewater treatment plant, a receiving water course or a retention pond designed to reduce


23/38

23

its flooding potential. It should be noted however that although storm water is usually low inpollutants, large volumes of it can interfere with the operational efficiency of a wastewatertreatment plant.

Objectives of this activityThe analysis of wastewater should:-

- introduce you to the most common tests used to assess the efficiency of a wastewatertreatment plant and the pollution loading being discharged into receiving waters

- Demonstrate the standard procedures/methods, tools, apparatus and equipment usedin an Environmental Laboratory.

- illustrate the shortcomings of these tests- Provide you with experience in analyzing results obtained from laboratory tests.

Learning OutcomesAt the end of this exercise the student will be able to: Identify the apparatus required for conducting some experiments Observe laboratory safety precautions Perform experiments in accordance with written procedures Obtain and tabulate readings and measurements with minimum error Manipulate and interpret laboratory data and use the results to infer wastewater quality Determine the performance efficiency of a wastewater treatment plant

ANALYSIS

For this lab you are provided with three (3) wastewater samples:-Sample 1- Influent (untreated sewage)Sample 2 - Effluent (treated sewage)Sample 3- Storm water taken from the retention pond north of Civil Engineering building

The following tests are to be performed on the samples provided.1- pH2- Settleable Solids (SS)3- Suspended Solids (TSS)4- Dissolved Oxygen (DO)5- Biochemical Oxygen Demand (BOD)


24/38

24

Test 1 pH

pH is the measure of hydrogen ion activity in the given sample. It indicates the nature (acidic,alkaline and neutral) of the sample. Two methods can be used: - Visual (comparative) andelectrometric using a calibrated pH meter with an electrode.

Use both test methods to determine the pH of all the wastewater samples.

Test materialspH papersCalibrated pH meter with electrodes100 mL beakersDistilled water

Procedure

a.

Using pH paper. Immerse the pH paper in the sample and remove it immediately. Compare and matchthe colors on the pH paper to the scale of colors provided. Record the value of thematched pH value.

b. Using the pH meter1. Rinse electrodes several times with the distilled water.2. Rinse the beakers with a little of the sample to be measured then fill it with approx.

100mL3. Immerse the electrodes in the sample.4. Use the magnet to slowly agitate the sample while allowing the meter to stabilize5. After 2-3 minutes record the pH value.6. Repeat the procedure for all samples.

Test 2 - Settleable Solids (SS)

The Settleable solids test (only done on wastewater) measures the volume of solids settlingfrom one liter of sample after a specific time period. This measurement can be used to indicatethe quality of wastewater coming into the plant and the settling behaviour of the solids in that

wastewater. The results can also be used to estimate the volume of sludge which willaccumulate in the clarifier, sedimentation tanks and ponds.

ApparatusImhoff cone and holding rackStirring rod and Timer


25/38

25

Procedure 1. Thoroughly mix the sample using the rotation method.2. Immediately after mixing, fill the Imhoff cone to the 1 liter mark with the sample.3. Allow settling for 45min. Then agitate by gently lifting and rotating the cone.4. Allow settling for a further 15mins

5. At the end of one hour settling time, record the volume of solids in the Imhoff cone.

Calculations The volume of solids settled is reported as:

Milliliters of settled solids per liter of wastewater mL/L

Test 3 - Total Suspended Solids (TSS)

Total suspended solids (TSS) include all particles suspended in water which will not passthrough a filter. Suspended solids are present in sanitary wastewater and many types ofindustrial wastewater. There are also nonpoint sources of suspended solids, such as soil erosionfrom agricultural and construction sites.The amount of suspended solids will usually increasewith the degree of pollution.

The Environmental Engineer can use the levels of suspended solids in a body of wastewater to: Size and design a wastewater treatment plant for that waste. Determine the performance of the various units of a treatment plant already in operation. Assess whether the waste effluent from a WWTP conforms to the required Effluent

Quality Standards before it is discharged.

ApparatusGlass-fiber filter discs (GFC- 934AH paper) Drying oven (103 o - 105 o)Aluminum containers Large tip pipettesFiltration apparatus Distilled waterAnalytical balance

Procedure1. Determine the mass of filter paper and aluminum dish (M1)2. Place the filter disc on the filtration apparatus, rinse with a small portion of distilled water

and suction dry.3. Use a magnetic stirrer and magnet to slowly mix sample.4. Pipette and filter 4 - 25mL volumes of sample taken from midway the total volume of

sample.


26/38

26

5. Rinse sides of apparatus with small portions of distilled water and suction the filter until itis very dry.

6. Transfer the filter back to the aluminum dish and put it to dry in an oven at 103 -105 o C for20mins. - 1 hour.

7. Cool the dish and filter paper, in the desiccators, for approx. 20 min

8. Re-weigh and record weight (M2) to obtain a constant weight.

Calculations TSS g/mL =ltered)mL sample fi(volume of

)g M (M 12

Report results in mg/L

Test 4 - Dissolved Oxygen (DO)

The level of dissolved oxygen (DO) in water is a common indicator of the health of a waterbody . Oxygen is measured in its dissolved form as dissolved oxygen (DO). If more oxygen isconsumed than is produced, dissolved oxygen levels decline and some sensitive animals andfish may move away, weaken, or die. DO levels in water bodies should therefore be maintainedabove 4mg/. DO levels in water can be determined using the classical Winklers (idometric)titration or the membrane electrode method

Principle of the Electrode MethodThe electrochemical method requires a cathode, anode,electrolyte solution and a gas permeable membrane(see figure). The membrane permits oxygen to passthrough. Oxygen consumed by the cathode creates apartial pressure across the membrane. It then diffusesinto the electrolyte solution. A DO meter actuallymeasures the pressure of oxygen in water.

Principle of the Winklers TitrationThe Winkler titration is used to determine the dissolved oxygen level in the water. A watersample is trapped in a completely filled DO bottle, which is a bottle with specially -designedcap (or specially-designed mouth and glass stopper) that allow for enclosure of liquids withoutcontact with air. Chemical reagents added in excess interact with oxygen to form a product,called a floc. The floc formed is acidified to release the DO and an other chemical (the titrant)is used quantitatively to neutralize that product. The amount of titrant needed is proportionalto oxygen concentration and is translated to mg/l. Ideally the DO in a sample should be fixed in


27/38

27

the field since the delay between the time collected and time tested may result in the DO beingaltered by atmospheric oxygen.

Materials

Burette, pipettes, Manganous Sulphate - reagent Ameasuring cylinders Alkaline Azide Iodide - reagent B250 mL beakers, Concentrated Sulphuric acid250 mL Erlenmeyer flasks Starch solution300 mL BOD bottles Sodium Thiosulphate (titrant)

Both the Winklers (idometric) titration and the meter/ electrode method will be used todetermine the DO levels in the following five (5) samples provided

Plant influent,Plant effluent,Pond water,Tap water andDistilled water

Please exercise caution with these reagents. Refer to the MSDS sheets (Appendix 1) forsafety information.

Winklers (idometric) titration Procedure

DO fixing step1. Carefully fill the five (5) 300 mL BOD bottles with each of the to overflowing .2. Remove air bubbles trapped in the liquid by gently tapping on each filled bottle using

the bottle cover, then stopper and rinse. 3. Add 2 mL reagent A to each bottle by placing the delivery pipette just below the level

of the sample .4. Replace the stopper, dump excess displaced liquid and rinse the bottle to prevent

contamination of the work space.5. Remove the stopper and add 2 mL reagent B to each sample in the same manner as

(3). 6. Repeat step 4 for all samples. 7. Gently invert each bottle several times to mix sample and reagents.8. Allow the floc formed to settle to approx. the sample volume.9. Repeat the inversion mixing and allow settling again. 10. After the second settling, carefully add 2 mL Conc. Sulphuric acid to each bottle by

holding the pipette just above the surface of the sample . 11. Cover bottle and invert until the floc is no longer visible.


28/38

28

Titration step12. Use a measuring cylinder to remove 201 mLs of the sample to a conical flask. 13. Record the initial volume of Sodium Thiosulphate in the burette. 14. Using the Sodium Thiosulphate, titrate against the sample in the flask, until the yellow

almost disappears. Stop here - do not record the burette reading.

15. Add 2 mL of starch to the sample, mix well to develop a blue color and continuetitrating to a colorless end point.

16. Record the final burette volume.17. Repeat the titration for all samples

DO in mg/l = Titrant volume in mls

Do Meter / Electrode Procedure

1. Place the probe in the sample.

2. Put on the probe to self-stir3. Allow time for the temperature and dissolved oxygen readings to stabilize. The amountof time varies with temperature, the condition of the probe and the dissolved oxygenlevel.

4. Read the dissolved oxygen and temperature off the meter display as shown in thefigure

NOTE: Temperature compensation of the dissolved oxygen reading is automatic

Test 5 - Biochemical Oxygen Demand (BOD)

The 5-day BOD (BOD 5) test is the most widely used indicator of organic pollution, applied toboth wastewater and surface water. BOD is a measure of the relative oxygen-depletion effectof wastewater contamination since it measures the oxygen demand of the biodegradablepollutants in water. The BOD 5 is also used to determine the strength of the wastewater(pollution loading) by measuring the amount of oxygen used by the bacteria in the wastewater


29/38

29

to stabilize the organic matter under controlled conditions (time and temperature). A majordisadvantage of the BOD test is the length of time (3- 5 days) it takes to obtain results.

Principle of the BOD methodA special airtight 300ml (BOD) bottle is filled with varying amounts of wastewater diluted using

specially prepared dilution water. The initial DO is measured and the sample is incubated atapprox. 20 o C for 5 days (standard) or 27 o C for 3days. The DO of the sample is measured afterthe incubation period and the BOD is calculated using the DO depletion.

Determination of sample sizeThe amount of sample used for the test is one of the most technical steps in the procedure.Generally, the BOD for most types of wastewater exceeds the amount of DO available in an airsaturated sample of pure, clean water - 9.2 mg/L. The wastewater must therefore be dilutedin order to ensure that sufficient oxygen is present in the sample bottle for the 5 day period . A good BOD dilution should give a residual DO of at least 1mg/L and a depletion of at least2mg/L .

Once a general range for the BOD of a particular wastewater sample has been established, thefollowing information is used to determine the dilutions which should ensure valid BOD resultsare obtained:-

1. The DO of the original, undiluted sample.2. The sample source (raw sewage, sewage effluent, river water, storm water).3. Previous BOD records for the same or a similar source.4. The COD of the sample if available (this test can be done in 2- 3 hours)

Materials 50mL graduated (straight) pipets,Measuring cylinders (100mL, 250mL)500mL volumetric flasksDO meter with probeBOD incubator at 35.5 or 27 oC300mL DO bottles and plastic sealing cupsDilution water aerated distilled with all reagents added.

Procedure1. Fill the BOD bottles provided with each of the three samples (Influent, effluent and pond)

2. Measure the initial DO of the samples, using the DO meter and record the values3. Prepare) sample dilutions using the instructions below.

1. Influent sample unfiltered 2%, 3% 2. Influent sample filtered 3%, 5% 3. Effluent sample unfiltered 20%, 30%4. Effluent sample - filtered 30%, 40%5. Pond water 50%, 60%


30/38

30

N.B: These dilutions may be adjusted depending on the nature of the sample on the day of thetest.

Convert % dilutions to volumes in 300 ml

4. Put the volumes of wastewater determined into the BOD bottles provided and then carefullyfill the bottles to the neck with dilution water provided.

5. Measure the initial DO value (I-DO) of each dilution using the DO meter.5. Record the BOD bottle numbers, sample dilutions and I-DO readings.6. Replace any dilution water displaced from the BOD bottle, ensure that no air bubbles are

trapped inside and then stopper tightly.7. Thoroughly rinse the outside of the bottle. Form a water seal at the top and cover with the

plastic cap provided.8. Prepare a dilution water blank (dilution water without sample)9. Incubate all the samples at 27oC for 3 days 10. After the 3 day incubation period , measure the Final DO value (F-DO).11. Calculate the BOD 3 using the equation below.

Calculations

BOD3, mg/L =V

DD 21x 300

Where - D1 = DO of diluted sample before incubation, mg/LD2 = DO of diluted sample after 3d incubation at 20 oC, mg/LV = calculated volume (ml) of sample used in the test

Note: If, after 3 days, the final DO is less than 1mg/L the BOD cannot be determined. Why?

If there are no obvious anomalies in the results, report an average of the threecalculated, BOD values as the final BOD in mg/L.

In this exercise, the dilution water blank is a check on the quality of the dilution waterand the overall cleanliness of the glassware used. It is therefore not necessary to correct

the calculations for the blank DO uptake. If this value is extremely high and it is clearthat the test might have been affected by the quality of the dilution water, the affectedresults will be disregarded.


31/38

31

Discussion

Interpret your results and in your discussion:

- Examine the accuracy of the pH and DO results and the practicality of using either ofthe two pH methods ( pH paper and pH electrode ) and either of the DO methods(Winklers titration and the membrane electrode ).

- Examine all other test results, stating possible sources of error.- Compare the results obtained to available Standards for Effluent Quality discharged

into a receiving water - Calculate the efficiency of the WWTP and discuss the plant performance.- Make engineering recommendations for improving plant performance and efficiency.- Say briefly how the effluent from this WWTP would impact the environment if it is

discharged into the environment.

General Questions

1. Why is it important to treat wastewater? Wastewater effluent that is discharged into theenvironment must be in compliance with certain standard values. What does compliancemean and what are the Standards for Trinidad & Tobago?

2. What factors control the DO levels in a stream? Wastewater from a food processing plantwith a BOD of approximately 15 000 mg/L is discharged into a low flow stream every day.What will be the long term and short term effects on the receiving environment?

3. Compare wastewater treatment using aerobic instead of anaerobic treatment methods?

4. How will extreme pH affect wastewater treatment and a water body (lake, pond, river)and what are the possible indicators of high (pH 10-12) or low (pH 2-4) in a water body?

5. Determine the 1- day BOD and the ultimate first stage BOD for a wastewater whose 5 -day 20 oC BOD is 600 mg/L. The reaction constant k (base e ) = 0.23d -1. What would havebeen the BOD 5 if the test was conducted at 25

oC and the samples were incubated forthree (3) days?


32/38

32

Activity 3 Field Trip

The field visit will be to the Caroni Water Treatment Plant in Piarco and the BeethamWastewater Treatment Plant in Port- of Spain

The Caroni Arena Water Supply System (CAWSS) provideswater to the North, West, Central and Southern regions ofTrinidad. The system is comprised of the Arena dam,reservoir and pump storage complex on the Arena tributaryof the Caroni River; the Caroni Water Treatment Plant; thetransmission pipelines and secondary pump stations andstorage reservoirs that store the treated water fordistribution to various areas. The Caroni Water TreatmentPlant treats water from the Caroni River. The Reservoir wascommissioned in 1981; the first (old) plant in 1981 and thesecond (new) plant in 2000.

The New Beetham Wastewater Treatment Plant is thelargest wastewater treatment facility in the Caribbean.The plant was commissioned in 2004. The 180 ML/dactivated sludge plant services Port of Spain and itsenvirons. It is constructed in a mangrove swamp andproduces a high quality effluent which is suitable fordischarge into the environmentally sensitive CaroniSwamp.

The field trip provides a great opportunity to understand the lecture notes. At the end of thetrip you should have a very good idea of the quality of the influent (raw water in the case ofwater treatment), the catchment areas from which it was derived, and the reason for thetreatment processes employed to produce the required effluent (product). Pay attention to theprocesses and the technologies used for ensuring consistent quality.

Health and SafetyThe plants are environments in which a significant number of persons work. Some are activelyinvolved in the operations to produce the effluent; others, such as the security officers and the

Arena Dam - CAWSS


33/38

33

janitors although not directly involved in the production may be on the plant for 8 hours at atime. Observe the environments of the plants to identify the health and safety hazards that areinherent in their operations and then find out the measures, both procedural and structural,that have been put in place, or should be put in place, to minimize the risk.

Here are some possible hazards. The list is not complete:

Exposure to chemicals ( water treatment) Exposure to contamination ( wastewater) Danger of falling into tanks, of great depth, with and without water; Ascending and descending ladders and staircases; Vehicular traffic to and from the location; Overhead and moving equipment; Dust; Noise;

Generally unsafe environment.

SustainabilityA few years ago, civil engineers boasted of their capability to treat any water or wastewater tothe required standards. Such gave little consideration to the resources required to do so.Therefore, low on the list of priorities was the protection of the watersheds to improve thequality of the raw water because it was felt that the required quality could have been achievedby increased chemical dosages. In the same vein, not much concern was given to the energyrequired for running the plants.

Now we are aware of the importance of designing sustainable systems and that if we use thatapproach in our practice then we will make more efficient and effective use of earths resourcesand so increase the chances that future generations will have sufficient resources to meet theirneeds.

As you tour the two treatment plants consider in the case of water treatment the raw waterquality and depletion, on one hand, and in the case of wastewater treatment the volume ofeffluent wastewater produced and which could be reused. Determine the processes, in terms

of the chemical requirements, the size of the tanks, and the energy required for running bothplants.

More Information on the operation of both plants will be provided by WASA personnel


34/38

34

Field Trip Report Format

Cover (Title) page Same format as the lab reports [2]

Abstract Provide a short (one paragraph) summary of the entire report. [3]

Objectives State the objectives of the exercise in your own words. [2]

IntroductionAddress the environmental/ health importance of treating wastewater and water[3]

TheoryProvide a brief summary of the theoretical underpinnings of both treatmentprocesses. Proper citation is required for all information used [5]

Treatmentprocesses

Using the undermentioned key words and terms describe the actual treatment

process used on both plants and the significance of each stage.

Wastewater treatment - head works/ wet well; Influent /Grit screening;Bioreactors / RAS/WAS/ anoxic zone / aerobic; Clarifier; UV treatment /disinfection; Sludge handling [10]Water Dam; Raw intake head works / raw water pumps; screening;coagulation/ flocculation; sedimentation/ sludge handling ; filtration;disinfection; distribution/ transmission system [10]

Flow diagrams should be included for both treatment processes.

Discussion

Discuss your observations in terms of the following:-

Engineering devices and operations used on each plant

Health and Safety practices and risk management

Sustainability

Quality assurance (QA) and quality control (QC)

Compare your findings with those given in lectures or other references. Further,discuss the degree of confidence you can place in the plant operations [10]

Avoid the temptation to repeat what you said in your introduction

Conclusion Summarize the key findings and whether your stated objectives were achieved [3]

ReferencesCite and reference all sources used ( including websites) using the proper(Chicago) style format [2]


35/38

35

References

1. (AWWA, APHA, WPCF) Standard Methods for the Examination of Water and Wastewater.2. Viessman W and Hammer M.J., Water Supply and Pollution Control.3. Peavy H.S, Rowe D.R, Tchobanoglous G, Environmental Engineering4. Sawyer C.N, McCarty P.L, Parkin G. F, Chemistry for Environmental Engineering.5. Relevant web sites6. Links to Material Safety Data Sheets (MSDS) below.

Substance Web page

MFC Agar http://www.oxoid.com/pdf/msds/EN/MM0747.pdf

M-endo Agar http://msds.egeneralmedical.com/em1.11277.0500.pdf

Aluminum Sulphate http://www.sciencelab.com/msds.php?msdsId=9922861

DPD - n n-diethyl-p-phenylenediamine sulfate

http://www.nwmissouri.edu/naturalsciences/sds/n/N%20N-Diethyl-p-phenylenediamine%20sulfate%20salt.pdf

Erichrome black T indicator https://www.google.tt/?gws_rd=ssl#q=eriochrome+black+t+indicator+msds

Ammonia buffer http://www.labchem.com/tools/msds/msds/75517.pdf

EDTA https://lifesciences.byu.edu/Portals/6/docs/EDTA.pdf

Screened Methyl Orange http://www.lovibondmsds.co.uk/msds/AS-K27629-KW_KS537_(GB).pdf

phenolphthalein indicator http://www.btps.ca/files/PDF/MSDS/Phenolphthalein_Indicator_Solution_528.00.pdf

Sulphuric acid http://www.sciencelab.com/msds.php?msdsId=9925146

Sodium Thiosulphate http://www.massasoit.mass.edu/assets/pdf/msds/sodium%20thiosulate%20pentayhydrate.pdf

Diphenyl carbazoneindicator

http://www.riccachemical.com/Technical-Support/MSDS/2600

Nitric Acid http://kni.caltech.edu/facilities/msds/Nitric_Acid.pdf

Mercuric nitrate http://www.labchem.com/tools/msds/msds/75496.pdfManganous Sulphate http://www.labchem.com/tools/msds/msds/75541.pdf

Alkaline Azide Iodide http://www.labchem.com/tools/msds/msds/LC10670.pdf

Starch solution http://www.sciencelab.com/msds.php?msdsId=9926918


36/38

36

Appendix 1

Water Quality Index - WQI

This weighting curve chart can be used to compute the Q-value for the fecal coliform test

1. Locate your test result on the bottom (horizontal or x axis) of the chart;2. Interpolate the Q-value for your test result using the following steps;

a. Locate your test result value on the hori zontal (x) axis of the chart. D raw a verticalline up until it intersects the weighting curve line;

b. From this point of intersection, draw a horizontal line to the left hand side (thevertical or y axis) of the chart;

c. Where this horizontal line intersects the vertical (y) axis of the chart, read off the Q value.

Fecal coliform (FC): colonies/100mlNote: if FC>100,000, Q=2.0


37/38

37

Jar Test Plots

A.

B.

Settled Turbidity as a Function of Alum Dose at 30 rpm

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35

Alum dose (mg/L)

Tubidity(NTU)
http://sarat212.files.wordpress.com/2013/01/paper20_clip_image006.gif


38/38

edited laboratory manual 2013-2014

Documents