Alternative Technologies for HEPA Filter

They aren't that expensive.... Just do it.

I have heared about UV technologies.. but not sure whether they can work like HEPA or not?

UV won't get rid of particulates, but it might zap some microoganisms that a HEPA filter could otherwise let through. Each individual situation should be studied.

If we combine UV with HEPA then will it help to improve life of HEPA?

I don't see how or why. Even if the UV kills a few bugs, they will still clog the HEPA filter.

What's your application?

You may use micro-cyclones but the power required is higher and there should be some noise. Such cyclones are used in home appliances to avoid use of filters. advantage the pressure drop does not change since there no clogging. I do not know how can this technology be implemented to big flows but it is not impossible.

The problem with particles is their form and very different specific weights, some will be retained some other not. It could be a possibility to combine both technologies with a pre-filtering via cyclones and a final with a barrier filter. This would make the "clogging time" a lot longer.

I echo this comment but without knowing your application it's hard to be exact. I've worked with Hepas a long time. You need to have a magnehelic gauge run across them to really tell when they're finished. It's just a pressure differential gauge. EVERY Hepa has a pressure drop rating. Get your rating, monitor the gauge weekly and you'll get the most bang for your buck. the gauged can be fixed in place or you can have 2 ports on either side of the filter and walk around with your gauge and test individual units. Most higher end filter banks have fixed gauges. For smaller equipment (like operating rooms) have ports on either side of their filter rack.

Usually pre-filter, fine filter and then HEPA filter is installed to reduce load on HEPA filters. It depends upon the cleanliness level and class .