Quality of Water - Environmental Engineering

Quality of water in environmental engineering is a vast topic that studies the suitability of water for various purposes. 

In this area of study, we measure the condition of the water relative to the standard requirements. To be more specific, under this topic, we will study:

1. Different Terminologies of Water
2. Different Types of Impurities in Water
3. Characteristic of water- Physical, Chemical and Biological 

A water treatment system takes water from a source, treat it and distribute it to the required demand. So how do we know whether the water is suitable? This is understood by performing certain test for quality. 

Water we acquire may or may not be good quality. Quality standards vary based on purpose. For example the water suitable for household is not suitable for drinking. So we need to set some standard values for water so that we can treat the water to reach these standards. 

In order to treat the water properly, we need to know what type of impurities is present. Each impurities require different treatment plan. All these basic overview before water treatment is studied under this title.

So this was an overview of why we study quality of water in detail while studying environmental engineering. 

Let's look in detail each features coming under the study of quality of water. 

Different Terminologies of Water

Some of the definitions associated with water in environmental engineering is mentioned:

1. Pure Water: It is the chemical compound H20.
2. Potable Water: It is the water that is fit for drinking.
3. Palatable Water: It is the water which looks good aesthetically
4. Wholesome Water:  Water which is not pure but it is fit for drinking
5. Polluted Water: Water with the presence of inorganic chemicals making it unfit for drinking.
6. Contaminated Water: Water with the presence of pathogens making it unfit for drinking.
7. Mineral Water: Water that contains all minerals necessary to human body in correct proportion. 

These definitions may be asked for PSUs or GATE exams.

Classification of Impurities in Water

Impurities in water can be classified into three main types:

1. Based on Size

The particles present in the water can be of different size, based on which it can be:

• Suspended = 10^-1 to 10^-3
• Colloidal = 10^-3 to 10^-6
• Dissolved = 10^-6 to 10^-8

2. Based on Nature

Based on nature of the impurities, it can be:

1. Organic Impurities: These are contaminants that come from living organisms. They are usually carbon-based materials. Eg. Decaying plants and leaves, Algae and microorganisms, Sewage and wastewater, organic chemicals, oils, fats, greases
2. Inorganic Impurities: These are non-living chemical substances that do not contain carbon–hydrogen bonds. Eg: Sand, silt, clay , salts

3. Based on State of Impurity

The state of impurity can be:

1. Physical impurities
2. Chemical Impurities
3. Biological Impurities

Characteristics of Water

The characteristics of water can be classified into:

1. Physical Characteristics of Water
2. Chemical Characteristics of Water
3. Biological Characteristics of Water

1. Physical Characteristics of Water

Physical properties of water defines those characteristics of water which responds to the the senses of sight, touch , smell and taste. 

The main physical properties of water that is studied in detail in water quality study are:

1. Temperature
2. Colour
3. Turbidity
4. Odour
5. Taste

2. Chemical Properties of Water

The main chemical characteristics studied in water is the presence of chemical matters in the water. These include:

1. Total Solids (TS)
2. pH
3. Hardness
4. Chlorides
5. Sulphates
6. Dissolved Oxygen
7. Fluorides
8. Nitrogen Compounds
9. Iron and Manganese
10. Toxic Chemicals

3. Biological Characteristics of Water

The presence of micro organisms is studied in biological characteristics of water. Here we study different microorganisms. It can be classified:

1. Based on the Food Requirement
2. Based on the living condition
3. Based on the Temperature Requirement
4. Based on their shape

Each physical, chemical and biological parameters are determined using special test and we follow an standard values for each parameter to conclude the quality of the water. 

The detailed study of each characteristics will be dealt in the upcoming articles. Until then , you can follow our YouTube channel Civil Engineering Fanatics for more civil engineering and construction videos. 

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