Water Treatment and Purification
There are a lot of pollutants in water that needs to be dealt with. All sources of water can be treated for suspended solids, colloidal particles, odour, etc through steps designed for specific purposes.

Pressure Sand Filters

Application

These filters are used to produce filtered water by removing suspended solids in the water.

Operation

These filters contain different layers of sand media viz., Gravel, coarse sand, fine sand. Raw/clarified water enters the filter from the top through the service inlet valve. The influent flows into the influent header at the top of the vessel which distributes the flow evenly over the cross section of the vessel. As the water is passed through the media, suspended solids get trapped in the media and clear filtered water comes out of the filter via the service outlet. Over a period of time, the filter will be exhausted, i.e. once the designed throughput has passed through the unit or high differential pressure is reached across the unit due to suspended solids getting trapped in the media. The unit will be taken out of service and ’BACKWASH’ is then carried out during which suspended solids trapped are dislodged & disposed. During backwash, backwash inlet & backwash outlet valves are opened & water flows in the opposite direction to the service flow. Prior to backwash, air-scouring is often carried out to enhance the effectiveness of backwash.

Multi-Media Filters

Application

These filters are used to produce filtered water by removing suspended solids in the water.

Operation

These filters contain different layers of sand media viz., Gravel, coarse sand, fine sand and Anthracite. The addition of Anthracite results in depth filtration enhancing the solids retaining capacity of the media and thus allowing for higher velocities compared to Pressure Sand Filters. Raw/clarified water enters the filter from the top through the service inlet valve. The influent flows into the influent header at the top of the vessel which distributes the flow evenly over the cross section of the vessel. As the water is passed through the media, suspended solids get trapped in the media and clear filtered water comes out of the filter via the service outlet. Over a period of time, the filter will be exhausted, i.e. once the designed throughput has passed through the unit or high differential pressure is reached across the unit due to suspended solids getting trapped in the media. The unit will be taken out of service and ’BACKWASH’ is then carried out during which suspended solids trapped are dislodged & disposed. During backwash, backwash inlet & backwash outlet valves are opened & water flows in the opposite direction to the service flow. Prior to backwash, air-scouring is often carried out to enhance the effectiveness of backwash.

Iron Removal Filter

Application

These filters are used to produce filtered water by removing suspended solids and Iron in the water.

Operation

These filters contain different layers of media and also a layer of Manganese Dioxide. Manganese Dioxide acts as a catalyst for removal of Iron from the raw water. Raw/clarified water enters the filter at top through the service inlet valve. The influent flows into the influent header at the top of the vessel which distributes the flow evenly over the cross section of the vessel.
As the water is passed through the media, precipitated iron gets trapped in the media and clear filtered water comes out of the filter via the service outlet. Over a period of time, the filter will be exhausted, i.e. once the designed throughput has passed through the unit or high differential pressure is reached across the unit due to suspended solids getting trapped in the media. The unit will be taken out of service and ’BACKWASH’ is then carried out during which suspended solids trapped are dislodged & disposed. During backwash, backwash inlet & backwash outlet valves are opened & water flows in the opposite direction to the service flow. Prior to backwash, air-scouring is often carried out to enhance the effectiveness of backwash.

Activated Carbon Filters

Application

These filters are used to produce filtered water by removing free residual chlorine, traces of organics, oil & grease etc. This is normally provided prior to resin based & membrane based units which are susceptible to fouling/ damage due to presence of the above contaminants.

Operation

These filters contain a gravel bed at the bottom which forms a support for the Activated carbon media. Water to be treated enters the filter from the top via. a service inlet valve. The influent flows into the influent header at the top of the vessel which distributes the flow evenly over the cross section of the vessel. The flow is directed downward through the media. As the water is passed through the media, activated carbon removes free residual chlorine, traces of organics, oil & grease etc. leaving clear filtered water out of the filter. As a result of suspended solids getting trapped in the media, the differential pressure builds up and a ’BACKWASH’ is then carried out during which the entrapped particles are dislodged & disposed. During backwash, backwash inlet & backwash outlet valves are opened & water flows in the opposite direction to the service flow.

Swimming Pool Filters

Application

These filters are used to produce filtered water by removing suspended solids / hair in the re-circulating swimming pool water.

Operation

These filters contain different layers of sand media viz., Gravel, coarse sand, fine sand. Raw/clarified water enters the filter at top through the service inlet valve. The influent flows into the influent header from the top of the vessel which distributes the flow evenly over the cross section of the vessel. Suitable strainers are provided in the system to remove hair etc from the water before it goes into the filter.
As the water is passed through the media, suspended solids get trapped in the media and clear filtered water comes out of the filter via the service outlet. Over a period of time, the filter will be exhausted, i.e. once the designed throughput has passed through the unit or high differential pressure is reached across the unit due to suspended solids getting trapped in the media. The unit will be taken out of service and ’BACKWASH’ is then carried out during which suspended solids trapped are dislodged & disposed. During backwash, backwash inlet & backwash outlet valves are opened & water flows in the opposite direction to the service flow.