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Distillation in Water treatment

Introduction

Distillation is a water treatment process that separates water from contaminants by boiling the water and then condensing the resulting water vapour. The contaminants are left behind in the water as it boils. Distillation is an effective way to remove a wide range of contaminants, including protozoan and some bacteria, as well as total dissolved solids(TDS), and other organic and inorganic contaminants. Also, it is a relatively simple and inexpensive process that can be used on a small or large scale.

Basic Concepts

The process of distillation takes advantage of the difference in volatility between water and the contaminants present in it. Volatility is a measure of how easily a liquid changes into a gas. Water is a relatively volatile liquid, meaning that it changes into a gas very easily. The contaminants present in water, such as dissolved solids and organic matter, are less volatile, meaning that they do not change into a gas as easily as water does.

When water is boiled, the water vapour rises and leaves the contaminants behind in the liquid water. The water vapour is then condensed back into liquid water, leaving the contaminants behind. The distilled water is free of contaminants and can be used for a variety of purposes, including drinking, food preparation and manufacturing.

Equipment and Techniques

A distillation unit consists of a distillation
column, a cooling system to separate water into liquid and vapour, and a
collection system. The distillation column is a vertical cylindrical vessel in which the process of distillation takes place. The column is divided into a number of plates or trays, which are stacked one on top of the other. The cooling system is located at the top of the column and helps to condense the water vapour. The collection system is located at the bottom of the column and collects the distilled water.

There are two basic types of distillation techniques:

1. Batch Distillation: This is the most common type of distillation and is used to process relatively small amounts of water. In batch distillation, the water to be treated is placed in the distillation column and then the column is closed. The water is then boiled and the water vapour rises up the column.
   
2. Continuous Distillation: This type of distillation is used to process large amounts of water. In continuous distillation, the water to be treated is continually introduced into the distillation column and the distilled water is
   continually collected. Using this technique, the feed water and heat are continually introduced into a distillation column at a controlled rate, and the distillate and waste are removed from the column continually.
   

Types of Experiments

There are a number of different types of experiments that can be performed to study the process of distillation. These experiments can be used to determine the efficiency of the distillation process, the effects of different operating conditions on the process, and the quality of the distilled water.

Some of the experiments that can be performed include:

1. Determining the efficiency of a distillation column: This experiment is used to determine the removal efficiency of the column. To do this, the feed stream is contaminated with a contaminant at a known concentration and this stream is pumped through the column. The
   distillate stream is then analysed to determine its concentration of the contaminant.
   
2. Effect of different operating conditions: This type of experiment is used to determine the effect of different process variables on the distillation process. The variables that are typically studied include:
   
   
   
   • Feed water flow rate
   • Reflux ratio
   • Column temperature
   
   
3. Assessing the quality of distilled water: This experiment is used to determine the purity of distilled water. The distilled water is analysed for the presence of various contaminants, such as TDS, organic matter, and bacteria.
   

Data Analysis

The data from the distillation experiments are used to determine the efficiency of the distillation process, the effects of different operating conditions on the process, and the quality of the distilled water. The data are typically analysed using a combination of graphical and
statistical techniques including :

1. Graphical techniques: The data are often plotted on graphs to show the relationship between different variables.
   
2. Multivariate analysis: These techniques are used to analyse the effects of multiple independent variables on a single dependant variable.
   

Applications of Distillation

Distillation is used for a variety of applications, including:

1. Drinking wa te production: Distillation is a common method for producing safe and drinkable water from contaminated water. Distilled water is free of microbiological contaminants and TDS.
   
2. Wastewater treatment: Distillation can be used to treat wastewater and remove contaminants. Distillation is an effective method for producing high-quality water from wastewater.
   
3. Industrial applications: Distillation is used in a number of industrial applications, such as the production of pharmaceuticals, chemicals, and food products.
   

Conclusion

Distillation is a versatile and effective water treatment process that can be used to remove a wide range of contaminants. It is a relatively simple and inexpensive process that can be used on a small or large scale.