Parameters of wastewater analysis

• Acidity• Sulphates• Volatile Acids• Nitrogen• Grease and Oils

ACIDITY

The quantitative capacity of water to neutralize a base is called “Acidity”.

The number of hydrogen atoms that are present determines acidity.

Acidity of natural water is caused by carbon dioxide or by strong mineral acids.

FIGURETypes of acidity of importance in ordinary water and waste water analysis, and the pH ranges in which they are significant

It is customary to consider that all water having a pH lower than 8.5 contain acidity.

Two types of acidity as follows1. Total acidity (phenolphthalein acidity)

2. Mineral acidity (methyl orange acidity)

ENVIRONMENTAL SIGNIFICANCE

Little concern from sanitary or public health viewpoint. No deleterious effect due to has been recognized. Acid water are of concern because of their corrosive

characteristics. must be calculated during after softening problems (using

lime or lime soda ash methods) pH Range should be 6to 9.5 for biological process of

treatment. Lower the pH in buffered lakes affecting aquatic life &

thus increases chemicals ( e.g. aluminium)

DETERMINATION OF ACIDITY

Mineral acids are measured titration to a of about 3.7, the methyl orange end point.

Titration of sample to the phenolphthalein end point of 8.3 measures total acidity.

Two methods of measurement of acidy

1. Titration method

2. Field method

MINERAL ACIDITY BURETTE : NaOH FLASK : Sample INDICATOR: Methayle orange

Bromophenol Blue COLOR CHANGE :

TOTAL ACIDITY BURETTE : NaOH FLASK : Sample INDICATOR: Phenolphthalein

Metacresol purple COLOR CHANGE :

Burette filling

Take

sample

Add indicato

r

Titrate

Take

readings

APPLICATION OF ACIDITY DATA

In public water supplies field To overcome corrosive characteristics resulting from

CO2 To choose the treatment method Estimation of the chemical requirement for softening

process To neutralize mineral acidity of wastes To determine quantities of chemicals, size of

chemical feeders, storage space, and costs

SULFATE

It is of considerable concern because it is indirectly responsible for two serious problem those are odor & sewer-corrosion often associated with the handling and treatment plant

It is of importance in public water supplies because of its cathartic effect upon human when it is present in excessive amounts.

The Sulfur Cycle

ENVIRONMENTAL SIGNIFICANCE

• Corrosion in sewer

• Odour problem

• Acid rain

• Water quality

METHODS OF ANALYSIS OF SULFATE

Ion chromatography Capillary ion electrophoresis Gravimetric Turbidimetric ( based on interference of precipitate)

Automated methylthaymol blue

APPLICATION OF SULAPHTE DATA

Consideration in determining their suitability for public and industrial water supplies

Knowledge of sulphate content of the sludge or waste fed to digestion units provides means of estimating S.

To determine whether scrubbing facilities will be needed to remove S and size of units requirement.

Knowledge of sulphate especially in anaerobic treatments is very useful.

Sulphate has highly adverse impact on methanogenic process. High sulphate concentration in ground water can hinder natural

anaerobic biodegradation of chlorinated solvents. In anaerobic treatment sulfur as sulphate ion,

In anaerobic treatment sulfur as sulphide.

VOLATILE ACIDS

Law molecular weight fatty acids are termed as volatile acids.

Distilled at atmospheric pressure Stages in methane fermentation

ENVIRONMENTAL SIGNIFICANCE

Control of anaerobic waste treatment process. Accumulation should be controlled or causes

disastrous effect Inhibitions caused results in decreased the rate of

destruction of volatile. Sludge must be removed or transferred

Important in detecting presence of unbalanced conditions in anaerobic treatment units.

DETERMINATION OFVOLATILE ACIDS

Two standard methods of measurement of volatile

acids

1. Chromatographic Separation

2. Distillation

Gas chromatography or ion chromatography are not

yet considered as standard.

CHROMATOGRAPHIC SEPARATION

Rapid method and it remove 100% all volatile acids. Two types of solvent are used Extracted volatile acids measured by titration with

NaOH to phenolphthalein end point.

R-COOH + NaOH R-CO+ + O Separation and titration should be done within a fame

hood because of carcinogenic potential of chloroform.

Sample on top

Mobile solvent

carries in

Differential migration

Soluble migrate

first

DISTILLATION

Routine determination, rapid and sufficient accurate method.

All low molecular weight fatty acids up to octanic acids have vapour pressure at 100º C.

Strong non-volatile acid like sulphuric, the organic acids are converted and can be distilled.

Distilled acids are measured by titration with NaOH solution to phenolphthalein end point.

Approximately 70% of volatile acids distilled from samples.

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