Various Technologies For Waste Water Treatment

The management of water has become a topic of serious concern with the increase in population and the increased demand for pure water. Water is very important for sustaining life on earth. Many people depend on ground water sources for their survival. A person requires about 135liters of water one day. Hence waste water management to increase the quality of water has become very important. Various techniques have now been found that depends upon the type and extend of contamination. Most of the waste water is treated in industrial scale waste water treatment plants. Some of them are listed below-

Decentralized Treatment 

This method is one of the most common waste water treatment methods used in the past. But this method has seen resurgence recently. It is an onsite or cluster waste water system used for treating small volumes of waste water. The size of such a system ranges from a single house to public facility for several households. There is no need of much equipment for this system as the distance between the collection point of waste water area and the origin point is less. Hence its cost is considerably less. The water treated by using this method can be used for landscape irrigation, toilet flush supply, cooling tower makeup etc.

Satellite Water Reclamation 

Such a system is an economically viable option when the need for reclaimed water is not located near an existing water reclamation plant. This method removes flows from nearby sewers to produce reclaimed water closer to use area. It can reduce the need for infrastructure pumps and pipes to return reclaimed water from a central plant. They are small waste water treatment plants. They usually treat the waste water from nearby large-diameter pipelines. The wastes thus produced are introduced back into the large-diameter pipeline for further treatment. It has an excellent odor removing ability and is designed to be neighbor friendly. This system produces only the quantity of reclaimed water needed. This system provides high quality reclaimed water at affordable cost.

Membrane Separation Technology

This method separates liquids from solids. The waste water is passed through a number of membranes to remove the impurities. The water treated by using this method is safe even to drink. This method is very effective in separating various mixtures of liquid materials in a growing range of applications. Ultra filtration, reverse osmosis and nanofiltration are the main types of membrane systems commonly used in industries. If membrane separation is used correctly they can provide financial savings and conserve resources. Using this technology, water can be purified and used in grey water applications, in irrigation or as a supplement to existing ground and surface water sources during times of low flow.

Resource Recovery from Waste Water

• Bio diesel from fats, oils and grease- Fats, oils and grease are collected during treatment in plants and then converted into bio diesel through esterification and hydrogenation.
• Electricity and heat from cogeneration- Biogas is a naturally occurring by-product of sludge dewatering. Electricity and hot water is produced from this biogas in cogeneration systems.
• Hydrogen from sludge dewatering plants- Methane from sludge dewatering plants can be converted into hydrogen which can be used in direct fuel cells. This helps in the powering of waste water plants.
• Biogas from waste water and sludge- Methane from sludge can be converted into hydrogen. But it can also be converted into biogas. Biogas can be used to fuel cars, taxis, trucks and public transportation.