Filter on Cooling Tower Sidestream

[ellent]

We are looking at installing a filter on the sidestream of a cooling tower. The following two technologies have been proposed.

I would like to understand the differences between a pressure media filter and a sand/gravity filter. Are there advantages/disadvantages to using either of these. Does one technology have better removal of small particles?

What type of filter have others used in this service?

Thanks for your help.

 

[cub3bead]

Since the media for either is usually the same, performance will similar. Biggest delta is the cost with the pressurized filter being the more costly due to code requirements. This assume you use similar applied rates to size the filters.

Are you going to filter the cooled water or the hot water? If it is the cooled water the gravity design is likely the best because you can let it flow back into the basin without affecting the cold water temperature.

I have always used gravity filters with an integral backwash storage tank so that I didn't have to deal with storing and pumping filtered water for backwashing the media. These normally have their outlet weir set about 12 feet above grade which allows the gravity flow back into the basin. Make sure you place the filter vessels so they do not interfere with the air flow into the tower.

 

[MJCronin]

ellen....

This is a good reference

http://www.process-cooling.com/CDA/...tures/BNP__Features__Item/0,3674,6593,00.html

Also this.... from the cooling tower doctor

http://www.ctdoc.com/Ch12.html

and..

http://www.ameriwater.com/cyclosnd.html

Please complete this thread by letting us know what you decide....

MJC

 

[bimr]

ellent

The advantage of pressure filters is that you can have higher throughput gal/sq.ft. than for gravity filters. That will allow the use of smaller filters. Throughput through gravity filters is limited by the water head across the filter. With pressure filters, you can also choose when you want to backwash, rather than waiting for the filter headloss to develop.

The filters will have the same performance in regards to filtering ability.

 

[luciom]

A side-stream self-cleaning pressure filter does a very good job; u fit it & forget it. I have used it with satisfaction.