Wastewater Treatment Practices in Pakistan (Part 4)

1-Wastewater treatment practices in Pakistan

1.1-Tertiary Treatment

It is much difficult than primary and secondary process. We use different kinds of Physical and Chemical means before its discharge to natural resources. It is clean and we should use it for agricultural and irrigation system. It provides us the final treatment stage. More than one kind of tertiary method is used in treatment plants. It includes;

• Filtration

• Disinfection

1.1.1-Filtration

Filtration f waste water helps to remove a large volume of suspended particles present in it. To remove residual toxins over activated carbon we simple use the filtration process.

1.1.2-Fixed Film Method

In fixed film method contains trickling filters and biological rotating chambers. We grow biomass in these chambers, while the sewage continuously moves over its surface.

1.1.3-Suspended Growth Method

In this method we use activated sludge, where biomass is well mixed with the wastewater. This solution is treated in a small chamber to react properly. This method provides higher rate for removal of organic suspended particles than the fixed film system. Roughing filters are fixed with the plants to treat the variable organic material which comes from industries. It further process for the conventional secondary mechanical methods. These filters are specially designed and have circular filters and open synthetic filters for the treatment of waste water.

1.1.4-Up Flow Anaerobic Treatment Reactor

This method is successfully used to treat different kinds of domestic and industrial solid waste generation. We simply conclude the procedure by describing its phenomena in which the water passes from sludge making channels. Sludge contains small granule like particles. Then we add some amount of influents from the bottom of channels where they react with the substrate particles. The velocity of the flowing influents must be slow that helps substrate to react properly with the biomass. It is highly recommended treatment system where no excess sludge production was made. The resting biomass is finely converted into biogas at the end of the reaction.

1.1.5-Disinfection

Main purpose to use disinfectants is to save the water from carcinogenic particles. It helps to reduce the number of biological particles to remain intact with the water. Its methodology depends upon the quality of water and other critical conditions. Methods of disinfections include;

• Exposure to Ultra-Violet radiations

• Chlorination

• Ozone method

From all the above presenting method exposure to UV radiations is the best method, because there is no use of harmful and toxic chemicals. Therefore, the treated water has no adverse impact on human health and marine life. As these radiations are highly penetrating, so they show adverse effect on the genetic structure of the biological organisms. UV radiations made them incapable of reproduction by destroying their genetic code of reproduction. In this way it protects the water from microorganism and made water clean for drinking purposes

Conclusion

Wastewater treatment is a network of technique designed to treat water for the process of removing contaminations from domestic and industrial waste. It includes different means of treatment like, Physical, Biological and Chemical. Various research surveys indicate that the water pollution has been remarkably increased in past few decades. This is due to the increase in urbanization and industrialization. A large number of industries, agriculture and domestic waste directly disposed and contaminate water bodies. Untreated hazardous material, toxic metals, fertilizers waste, municipal waste and other toxic pollutants adds up the pollution in water and cause water borne diseases. We observe the graphical data and related surveys we comes to the conclusion that almost 27 percent of the world population has lack of access to clean water for drinking purposes. The collection and treatment of the sewage is directly relates to the National and local authorizes with regulations. This treatment process involves three main stages, Primary stage, Secondary stage and tertiary stage. Primary method is used for the removal of material that easily be separated from the waste water before it blocks the pipelines or damage the clogs of pumps. In secondary method we remove dissolved and suspended particles. This method is specially designed to remove biological content, derived from human waste, organic and industrial waste. While tertiary treatment is the final stage of water where we use chemical or physical means to purify water and make it portable for drinking purposes.