CE4305 Characterstics and Composition

7/24/2019 CE4305 Characterstics and Composition

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Typical Engineered system ofWater Treatment

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C apter 2: WastewaterCharacteristics and treatment


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Module Contents2. Wastewater characteristics and treatment Characteristics of wastewater

Wastewater treatment plant design (impacts of flow rate andmass-loading factors on design, evaluation and selection of designflow rates, forecasting average flow rate, evaluation and selectionof design mass loading rates, variations in concentrations ofwastewater constituents, process selection)

Theoretical aspects and basic design and operational concepts ofpreliminary wastewater treatment processes (screens,comminutors, grit removal, oil and grease removal, pre-aeration)

Theoretical aspects, and basic design and operational concepts of

primary wastewater treatment processes (primary sedimentation)

Theoretical aspects and basic design and operational concepts ofsecondary wastewater treatment processes (application of kineticsof biological growth and substrate utilization in biologicaltreatment, activated sludge process, tricking filters, bio-towers)

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Type of Wastewater

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Wastewater (WW)

Domestic WW(Low strength)

Gray water Sewerage

Industrial WW(High strength)


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Sources of Waste

Domestic wastewater

Residences, non-industrialbusinesses, institutions

Relatively uniform incomposition

Industrial wastewater

Industries and commercial

users Variable in composition

May contain toxic substances


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Characteristics of Waste

Domestic Wastewater

99.94% water

0.06% waste

Characteristics depend on nature of source

Wide variations between waste streams

Seasonal variations within one wastestream

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Types of Waste

OrganicPlant or animal origin

Contain organic carbon

Biodegradable Inorganic

Materials of non-organic origin

Sand, silt, nutrients, metals, saltsResistant to decomposition

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Characteristics of wastewater

Physicalcharacteristics

Chemicalcharacteristics

Biologicalcharacteristics

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In terms of Concentrationswastewater characterize wastewater as:

weak,

medium, and

strong

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Characteristics of wastewater

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Characteristics of

wastewater

Physical

SolidsParticle size distribution

Odours

Temperature

Colour

Density

Turbidity

Chemical

Organic:COD

BOD

TOC

Inorganic:

Heavy metalsNutrients (N,P,)

pH

Gasses:H2S

CH4

Biological

Micro-organisms

PathogenicOrganisms


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Physical characteristics

Solids

Particle size distribution

Odours

Temperature

Colour Density

Turbidity

The physical characteristics of wastewater include those items that

can be detected using the physical senses

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Colour Raw wastewater: gray After more anaerobic conditions are developed, it

turns to dark gray and ultimately, to black. Pretreatment and industrial inputs affect colour

When the colour of wastewater is black, it is called'septic'

These colours are due to formation of metallicsulphides. The sulphides produced in the anaerobicconditions react with metals in the wastewater toproduce metallic sulphides.

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Odour

Raw wastewater: musty odourOdours in domestic wastewater usually arecaused by gases produced by the decompositionof organic matter or by substances added to the

wastewater.

Industrial wastewater may contain eitherodorous compounds or compounds that produce

odours during the process of wastewatertreatment.

Odours have been rated as the foremost concernof the public relative to the implementation of

wastewater treatment facilities. 16



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Within the past few years, the control of odorshas become a major consideration in the designand operation of wastewater collection,

treatment, and disposal facilities, especiallywith respect to the public acceptance of thesefacilities.

In many areas, projects have been rejectedbecause of the concern over the potential forodors.

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Temperature The temperature of wastewater is most probably higherthan that of the water supply.

That is because of addition of warm water from householdsand industrial activities.

It effects on chemical reactions and reaction rates, aquaticlife and suitability of the water for beneficial uses.

Elevated temperature:

Makes oxygen less soluble in water (Depletion indissolved oxygen).

Can cause a change in the species of fish that can exist inthe water body receiving the wastewater.

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Turbidity

Turbidity is a measure of the light-transmittingproperties of water.

The colloidal and residual suspended matter causeturbidity.

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Turbidity is an issue because:

1. It looks bad human aesthetic.

2. It causes filter contamination financial

aesthetic.

3. It causes interference in analysis, especiallyoptical chemists aesthetic


M f T bidi


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Measurement of Turbidity

A turbidimeter is an optical device that measures the scattering oflight, and provides a relative measure of turbidity in Nephelometer

Turbidity Units (NTUs)

Turbid meter can be used to measure turbidity in the units ofNTU or JTU.


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Density The density of a wastewater sample is the mass for unit

volume

This is temperature dependent This value varies with the concentration of the total

solids in the wastewater.

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Information on particle size is of importance in assessing theeffectiveness of treatment processes (e.g., secondarysedimentation, effluent filtration and effluent disinfection).

The biological conversion rate of these particles is dependenton size.

Attachment of other pollutants to the solids is dependent on

particle sizesThe methods used most commonly to study and quantify theparticles in wastewater are serial filtration, electronic particlecounting, and microscopic observation .

Particle Size Distribution

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Solids

The separation of solids is one of the primaryobjectives of wastewater treatment

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Solids: who cares? Biological treatment demand

Lots of organics associated with solids Has to be accounted for in design

Physical demand Solids take up space in tanks Settleable solids dictate initial treatment steps Sand and grit wears pumps and pipes

Attenuate UV light during disinfection

Quantity of ultimate residue (sludge orbiosolids) affected by influent solids

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Solids Solids comprise matter of suspended or

dissolved in water and wastewater.

Removal from wastewater is critical Decrease efficiency of disinfection systems Clog surface irrigation equipment

Solids are divided into several differentfractions;

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Interrelationships of solids in water and Wastewater


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SampleImhoff

Cone

Settaleable

SolidsTS

Evaporation

Filter (Glass

Fiber)

Evaporation of Filter Evaporation of Filtrate

Muffle Oven Muffle Oven

VSS FSS VDS FDS

TVS

TSS TDS

TFS

TS

Interrelationships of solids in water and Wastewater


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TS - Total Solids

TSS - Total Suspended Solids

TDS -Total Dissolved Solids

VSS- Volatile Suspended Solids

FSS- Fixed Suspended Solids

VDS- Volatile Dissolved Solids

FDS -Fixed Dissolved Solids

TVS - Total Volatile Solids

TFS- Total Fixed Solids

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Solids Contd:Total solids (TS)

Material left after evaporation of wastewater

Includes dissolved and suspended solids

TS = TDS + TSS

Determination of total solids:-

A well mixed sample is evaporated in a weighed

dish and dried to a constant weight in an oven at

103C to 105 C about 24 hr. The increase in

weight over that of the empty dish represents the

total solids.

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Solids Contd:

Where,

A = Weight of dried residue plus dish (mg)

B = Weight of dish (mg)

Calculation of TS

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Solids Contd:


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Total solids (TS), or residue upon evaporation, can be

further classified as nonfilterable (suspended-TSS) orfilterable(dissolved-TDS) solids.

Solids Contd:

TS

TDSTSS

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Solids Contd:

Total suspended solids (TSS)

The solids remaining on a glass-fiber filterpaper after a known volume of a wastewater ispassed through the filter paper.

Removed by physical, biological or chemicalprocesses

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Determination of suspended solids :-

A well-mixed sample is filtered through aweighed standard glass- fiber filter paper andthe residue retained on the filter is dried to a

constant weight at 103C to 105

C.

The increase in weight of the filter representsthe total suspended solids.

Nominal pore size of the filter paper is 1.2-2micrometers.

Solids Contd:

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Determination of suspended solids :-

contd:

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Solids Contd:

Whatman934-AH Glass Microfiberfilters are designed forthe analysis of suspended solids.

A generalized protocol for the analysis of suspended

solids with Whatman 934-AH Glass Microfiber filters. 36


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Calculation of TSS

Solids Contd:

Where, C = Weight of filter paper and crucible plusdried residue, mg

D = Weight of filter paper and crucible, mg

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Total dissolved solids (TDS)- Filterable

Solids Solids that pass through very fine filter

Difficult to remove from wastewater

Solids Contd:

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Determination of filterable solids:-

A well-mixed sample is filtered through astandard glass-fiber filter paper and the

filtrate is evaporated to dryness in aweighed dish and dried to a constantweight at 180 C.

The increase in weight represents the totalfilterable solids.

Solids Contd:

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Calculation of TDS

Solids Contd:

WhereE = Weight of dried residue plus dish, mg

F = Weight of dish, mg

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Solids Contd: Volatile and fixed solids

The organic fraction of solids is called the volatilesolids.

This will oxidize and be driven off as gas at thetemperature 550C 50C.

i.e. Volatile Solids = solids burned away @ 550 600 C

The inorganic fraction remains in ash.

The organic fraction present in the suspended solids is called

volatile suspended solids and the inorganic fraction in

suspended solids is denoted asfixed suspended solids. 41


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Determination of volatile and fixed solids/Suspended solids: -

The residue from the total solid test is ignited to aconstant weight at 550C.

The remaining solids represent the total fixed solids

while the weight lost on ignition is the total volatilesolids.

The residue from the suspended solids test is ignited to

a constant weight at 550

C.

The remaining solids represents the fixed suspendedsolids while the weight lost on ignition is the volatilesuspended solids.

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Settleable solids refers to those solids that willform sediment if not stirred up. Can bedetermined by simply allowing the material to

sit in an Imhoff cone for an hour.

It is expressed as mL/L.

This is approximately the quantity of sludge thatis removed by primary sedimentation.

Solids Contd: Settleable solids

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Imhoff cone for settleable solids

Solids Contd:

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S l d S


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Solids- SummaryDefined by residue remaining following test

TS: whats left after evaporating at 103 C- 105 C TVS: the TS that combust/ignite at 500 C TFS: residue of TS that remains after combustion/

ignition

TSS: dry (103 C- 105C ) solids retained onfilter (1.2-2 mm)

VSS: combustible TSS FSS: noncombustible TSS

TDS: dry solids that pass through filter VDS and FDS (as above) Settleable solids: what settles out over a set time

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Ch i l h i i


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Chemical characteristics

Org

anic

ma

tter

Inorganic

ma

tter

Gasses

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Ch i l h i i


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Organic compounds are normally composed of a

combination of carbon, hydrogen, andoxygen together with nitrogen in somecases.

Other important elements, such as sulphur,phosphorus, and iron, may also be present.

Organic matter

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Chemical characteristics


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The principal groups of organic compoundsfound in wastewater are :

Proteins

CarbohydratesFat oils and grease

Surfactants

Priority pollutants

Volatile organic compounds

Pesticides and agricultural chemicals

Organic matter Contd:

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The amount of organic matter presentdetermines:

The amount of O2 needed for biological

treatment

The size of waste treatment facility

needed

The efficiency of the treatment process

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There are three methods commonly usedin determining gross organic content.

Chemical Oxygen Demand(COD)

Total Organic Carbon ( TOC )

Biochemical Oxygen Demand ( BOD)

Organic matter Contd:

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Chemical Oxygen Demand(COD)

Amount of organic matter oxidized bychemical oxidant

Another way to measure organic

contentResults in 3 4 hours

Typically higher than BODBut not a direct correlation

Need to establish ratios58

T l O i C b ( TOC )


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Total Organic Carbon ( TOC )

TOC is measured using a TOC analyzer. The

sample is combusted and organic carbonquantified using infrared detection.

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Biochemical(Biological) Oxygen


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Biochemical(Biological) OxygenDemand ( BOD)

Rate that organisms use oxygen to break

down organic matter. High levels indicate high levels of organic

matter.

The BOD test was developed in 1930s. Thisis a five day test that measures the amount ofO2 consumed in a wastewater sample by amixed population of heterotrophic bacteria in

the dark at 20o

C . BOD of influent determines pre application

treatment

BOD5

test takes 5 days60



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Definition: The amount of dissolved oxygen utilized

(demand) by microbes during the degradation of organic

matter to CO2 and H2O under aerobic conditions under

particular temperature and incubation period. BOD of wastewater is typically 110-440 mg/L and

must be reduced to 20 mg/L for discharge.

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2 2 2Organic matter + O CO +H O + cell mass

C

C

Biochemical Oxygen Demand (BOD) exerted by

during bacterial oxidation

(25 %)

(75 %)

BOD is difficult to calculate so an experimental

procedure is used to measure it.

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Dissolved Oxygen (DO) Amount of oxygen

dissolved in water Presence of DO

Aerobic conditions

Absence of DO

Anaerobic conditions

Most wastewater treatmentprocesses

Require aerobic conditions Cannot occur in anaerobic

conditions

L b t BOD T t


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Laboratory BOD Test

Provide microbes with D.O and measure D.Oconsumption after 5 days in a closedenvironment (BOD bottle)

Also provide all nutrients for the growth(Domestic wastewater is an exception)

BOD = [(D.O)i- (D.O)f] Dilution factorIf (D.O)i= 9.0 mg/L (Saturation level @20 C)

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Measurement of BOD

StandardizedNeed:IncubatorBottlesDO meter

Dilution waterSeed (opt.)Expressed in mg/L

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E ti l f BOD T t


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Essentials for BOD Test

Dissolved Oxygen (D.O or D)

Organic Matter

Micro organisms Nutrients

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Calculation of BOD


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Calculation of BODUndiluted sample

mg BOD/L = D1-D2Where, D1= Initial Dissolved Oxygen

D2= Final Dissolved Oxygen after 5

days

Diluted sample: If dilution water is not seeded

A

B

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AirEssentialnutrients(N,P,K,Fe, etc.)

and otheradditives

Glasscontainer

(20L) Distilledwater

Air stone

Unseededdilution

water

Dilution water(300ml - Vs)

Test (waste) sample,Vs ,

containing organicmatter and an

adequate number ofbacteria (volume oftest sample dependson estimated BOD)

Glass stopperedBOD bottle

(volume = 300ml)

BOD bottle filled with testsample plus unseeded dilutionwater (unseeded test sample)

Procedure for setting up BOD test bottles -with unseeded dilution water

Example: 5 ml wastewater is added to a 300 ml


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Example: 5 ml wastewater is added to a 300 mlBOD flaskD

i= 8 mg/L D

f= 2 mg/L

DF = 300 = 605

BOD = (8 2) x 60 = 360 mg/L

BOD = (D1 D2)x DF

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Dil t d l If dil ti t i d d


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Diluted sample: If dilution water is seeded

When testing waters with lowconcentrations of microorganisms, aseeded BOD test is conducted .

The organisms contained in the effluentfrom primary sedimentation facilities areused commonly as the seed for the BODtest. Seed organisms can also be obtained

commercially.When the sample contains alarge population of microorganisms(e.g:untreated wastewater), seeding is not

necessary. 75

P d f i BOD b l


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Essentialnutrients and

additives

Air

Dilution water(300ml - Vs)

BOD bottle filled with testsample plus seeded dilutionwater (seeded test sample)

Seededdilution

water

Bacteria

(seed)

Distilledwater

Dilutionwater (300ml )

Test (waste) sample,Vs ,

containing organicmatter and no

bacteria or a limitednumber of bacteria

BOD bottle filledwith seeded dilutionwater (seeded blank)

Procedure for setting up BOD test bottles -with seeded dilution water

Diluted sample: If dilution water is seeded


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OR

Contd:

C

D

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BOD Test Contd:


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BOD Test Contd: Longer time periods (typically 7 days), which correspond

to work schedules, are often used, especially in smallplants where the laboratory staff is not available on the

weekends.

The 20 temperature used is an average value for slow-moving streams in temperate climates and is easilyduplicated in an incubator.

After incubation, the dissolved oxygen of the sample ismeasured and the BOD is calculated using one of theabove formulas A, B or (C or D).

Within a 20-day period, the oxidation of thecarbonaceous organic matter is about 95 to 99 percentcomplete, and in the 5-day period used for the BOD test,oxidation is from 60 to 70 percent complete.

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Time (days)

Oxygenconsumed

5 20

BODL

BOD5

BOD5 = 2/3 BODL

Effect of particle size on BOD Reaction Rates

The observed BOD reaction rate coefficients are affected

significantly by the size of the particles in wastewater. 81

The limitations of the BOD test are :


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The limitations of the BOD test are :

(1) A high concentration of active, acclimated seedbacteria is required;

(2) Pretreatment is needed when dealing with toxicwastes, and the effects of nitrifying organismsmust be reduced;

(3) Only the biodegradable organics are measured;(4) The relatively long period of time required to

obtain test results.

Of the above, perhaps the most serious limitation isthat the 5-day period may or may not correspond tothe point where the soluble organic matter that is

present has been used. 82

Kinetic Aspects of BOD


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Kinetic Aspects of BOD

Microbes consume organic matter as afunction of time (No instantaneous

consumption of DO)

BOD exertion/Organic matter consumption

First order equation

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=

K

BOD rate is constant

0

= 0

ln

0=

= 0 L0is Ultimate oxygen demand. Oxygen for the

oxidation of initial organic matter (first stage BOD,

mg/l)

L is BOD remaining after time t days, mg/l

K is deoxygenation rate

e is base of natural logarithm

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Formation of the first stage BOD curve


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g

= 0

= 0 0

= 0(1 ) 85

OM what ever remaining in the systemafter time t

BOD Exerted


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Carbonaceous & Nitrogenous BOD

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Nitrification in the BOD test


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Non-carbonaceous matter, such as ammonia, isproduced during the hydrolysis of proteins.

Two groups of autotrophic bacteria are capable

of oxidizing ammonia to nitrite andsubsequently to nitrate.

Nitrification occurs If nitrogen is present, as organicnitrogen or as ammonia

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The oxygen demand associated with the oxidation of ammonia tonitrate is called the nitrogenous biochemical oxygen demand


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nitrate is called the nitrogenous biochemical oxygen demand(NBOD).

Because the reproductive rate of nitrifying bacteria is slow, itnormally takes from 6 to 10 days for them to reach significantnumbers and to exert a measurable oxygen demand.

When nitrification occurs, BOD test is erroneous.

However, if a sufficient number of nitrifying bacteria are presentinitially, the interference caused by nitrification can be significant.

The interference caused by the presence of nitrifying bacteria forCBOD test can be eliminated by pretreatment of the sample or by theuse of inhibitory agents.

Pretreatment procedures include pasteurization, chlorination and

acid treatment. 88

Chemical characteristics contd:


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Alkalinity

Alkalinity in wastewater results from the presence of the

hydroxides [OH-], carbonates [CO32-], and bicarbonates

[HCO3

- ] of elements such as calcium, magnesium,

sodium, potassium, and ammonia. Of these, calcium and

magnesium bicarbonates are most common.

The alkalinity in wastewater helps to resist changes inpH caused by the addition of acids.

Alkalinity is determined by titrating against a standard

acid .


Inorganic matter

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Heavy metals

Inorganic matter Contd:

Inorganic chemical elements

Stable compounds that resist decomposition

Some are essential nutrients for plants andanimals

Toxic at high concentrations

Low levels usually in domestic wastewater High levels more common in industrial ww

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Heavy Metals Contd:

Metals of concern Cadmium Molybdenum

Arsenic Lead

Copper Manganese

Mercury Nickel

Zinc

Nutrients:h l h h l h h f


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The elements which are essential to the growth ofplants and as such are known as nutrients or bio-stimulants.

Nutrients are chemical compounds such as nitrogen,phosphorus, carbon, calcium, potassium, iron andmanganese.

Excess nutrients can be considered as pollutantswhen their concentrations are sufficient to allow

excessive growth of aquatic plants such as algae. Nutrient enrichment which is referred to as

eutrophication can lead to blooms of algae whicheventually die and decompose resulting in oxygendepletion.

From a water quality perspective, nutrients that playthe most vital role in the deterioration of water qualityare nitrogen and phosphorous.

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Nitrogen (N)


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Nitrogen (N)

Four forms of N occur in wastewater

Organic nitrogen

Ammonia (NH3) / ammonium (NH4+)

Nitrite (NO2-)

Nitrate (NO3-)

Organic N is converted to NH4+

NH4+ is then converted to NO2

- and NO3-

The chemistry of nitrogen is complex because of theseveral oxidation states .

Nitrogen (N) contd:


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Nitrogen (N) contd:

Total N

Organic N + NH3 + NO2- + NO3- Total Kjeldahl N (TKN) - Total Kjeldahl

nitrogen is the total of the organic andammonia nitrogen.

(Organic N + NH3)

To determine organic N, NH3 must bemeasured and subtracted from TKN

Plant available N (PAN) N that is readily available to plants

NH4+ & NO3

-

Total = (TKN)+(NO2- + NO3

-)

Nitrogen (N) contd:


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Ammonia nitrogen exists in aqueous solution as either theammonium ion (NH4

+) or ammonia gas (NH3), depending on

the pH of the solution.

Nitrite nitrogen, determined colorimetrically, is relativelyunstable oxidized to the nitrate form. Nitrite can be very

important in wastewater or water pollution studies because it isextremely toxic to most fish and other aquatic species . Nitritespresent in wastewater effluents are oxidized by chlorine andthus increase the chlorine dosage requirements and the cost ofdisinfection.

The U.S. EPA primary drinking water standards limit nitrogento 45 mg/L as NO3

-, because of its serious and occasionallyfatal effects on infants. Nitrates may vary in concentrationfrom 0 to 20 mg/L as N in wastewater effluents.

g ( )

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Nitrogen (N) contd:


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Decomposition by bacteria readily changes theorganic form to ammonia. The age of wastewater

is indicated by the relative amount of ammoniathat is present.

The predominance of nitrate nitrogen in

wastewater indicates that the waste has beenstabilized with respect to oxygen demand.Nitrates, however, can be used by plants andanimals to form protein.

Nitrogen (N) contd:

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Phosphorus


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Originates from wastes and phosphate

builders in detergents and soap powders.

Municipal wastewaters may contain from 4

to 16 mg/L of phosphorus as P.

Three major forms in wastewater:Orthophosphate (soluble)

Organic phosphate (soluble and particulate)

Polyphosphate (hydrolyse to formorthophosphate)

Organics (BOD) limits N and P reduction. Advanced

treatment is required to remove excessive N and P. 113


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Log of H+ ions in solution 7 is neutral

< 7 indicates acid conditions

> 7 indicates basic conditions

Domestic wastewater Ranges from 6.5 to 7.5

Rapid changes Kill bacteria

Poor wastewater treatment

pH

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Gases commonly found in untreatedwastewater include nitrogen (N2), oxygen (O2),carbon dioxide (CO

2), hydrogen sulfide (H

2S),

ammonia (NH3), and methane(CH4).

The latter three are derived from the

decomposition of the organic matter present inwastewater and are of concern with respect toworker health and safety.

Gases

C e ca c a acte st cs co td:

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Hydrogen Sulfide

Hydrogen sulfide is formed from thereduction of mineral sulfites and sulfates .This gas is a colorless, inflammable

compound having the characteristic odor ofrotten eggs. The loss of smell can lead to afalse sense of security that is very dangerous.The blackening of wastewater and sludge

usually results from the formation ofhydrogen sulfide .Various other metallicsulfides are also formed.

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Methane


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Met a eMethane is a colorless, odorless, combustiblehydrocarbon of high fuel value.

Because methane is highly combustible andthe explosion hazard is high, access ports(manholes) and sewer junctions or junction

chambers where there is an opportunity forgas to collect.

Should be ventilated with a portable blower

during and before the time required foroperating personnel to work in them forinspection renewals, or repairs.

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Biological characteristics


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The biological characteristics of wastewaterare of fundamental importance in thecontrol of diseases caused by pathogenic

organisms of human origin, and because ofthe extensive and fundamental role playedby bacteria and other microorganisms in the

decomposition and stabilization of organicmatter, both in nature and in wastewatertreatment plants.

Biological characteristics

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Micro-organisms


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Organisms found in surface water andwastewater include bacteria, fungi, algae,protozoa, plants and animals, and viruses.

Living single-cell microorganisms that can onlybe seen with a microscope are responsible for theactivity in biological wastewater treatment.

The prokaryotes have the simplest cell structureand include bacteria, blue green algae(cyanobacter), and archaea.

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Pathogenic organisms


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Pathogenic organisms may be infected with diseaseor they may be carriers of a particular disease.

Sometimes, pathogenic organisms may bedischarged by human beings.

Bacteria, viruses, protozoa and helminthes (parasitic

worms) are categorized as pathogenic organisms. Many cant survive outside human intestinal tract

Enough remain to cause severe problems if notproperly treated

g g

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Indicator Organisms


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g Testing for all pathogens is impractical

The pathogenic organisms being present in

wastewater are few and difficult to be isolatedand identified.

Coliform organisms are very high in number.

They can be very easily tested.

Therefore, coliform organism is used as anindicator organism.

Ex: Total coliform, fecal coliform

These are used to characterize wastewater in/out of

treatment process, and to monitor water safety 122

Membrane Filter Technique


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123

q

Pour medium onto absorbent pad in petri dish

Shake sample vigorously Measure appropriate volume Filter sample or sample aliquot through a membrane filter,

diameter 47 mm, mean pore diameter 0.45 um

Rinse funnel with approx. 30 mL of dilution water Place filter on a pad in petri dish with a selected medium Incubate inverted plate Count colonies Record results Perform confirmatory tests when needed Run appropriate blanks, known positive and known negative

Membrane Filter Technique


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IncubationAutoclave

Colony counter

Total coliform


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Culture medium (2mL) LES Endo agar M-Endo agar or broth Incubation 35 0.5oC 22 to 24 hours

Produce dark, red colony withmetallic sheen

Many background colonies usually are observed

At least three sample dilutions should be setup

Up to 80 TC colonies can be counted if no more than 200total colonies (including background) are noted

Fecal coliform


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Most commonly used method

Culture medium (2 mL) M-FC broth (96 h shelve life)

M-FC agar (2 weeks shelve life)

Incubation

44.5 0.2oC 24 2 hours

Count blue colonies; can be

different size and shade

Few background colonies usually are observed due toselectivity of medium, especially if rosalic acid is added

At least three sample dilutions should be setup

Up to 60 FC colonies can be counted

Wastewater Composition


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CE4305 Characterstics and Composition

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Transcript of CE4305 Characterstics and Composition