You can use filter assembly systems as in here: https://www.merckmillipore.com/INTL/en/product/Laboratory-Filtration-Systems,MM_NF-C10732

Chakkiath Paul Antony Thank you for a quick and helpful reply.

Hello Maninder,

I think you should use a 0.22 micron filter paper (Millipore) instead of 0.45 micron to obtain all the bacterial load in the water sample. You can either purchase the large sheets or the discs from this make. In case of the sheets, you need to first cut it to desired diameter and then autoclave them for use, whereas the discs can be autoclaved directly and used. Plus you can filter the water using a serile- autoclaved filtration unit with the help of a vacuum pump creating negative pressure. Once all the water sample is filtered, pick up the filter paper using a pair of forceps to place it on the surface of agar plate (preferably an enriched media) and incubate it under desired temperature conditions.

I hope this works for you. Good luck! Happy new year.

Sathi Mallick has given a nice detailed answer and I agree with everything that she has mentioned. To add a bit more to her answer: depending upon the source of your water sample (i.e., in case you have a lot a macroscopic particles such as algae/plant biomass etc.), you might need to do an additional pre-filtration step at the beginning (for e.g., with sterilized Whatman filter paper) so as to prevent your 0.22 micron filters from getting clogged very quickly during the filtration process

Thank you Antony Sir and Mallick Mam. I am thinking to use Borosil filtartion assembly as attached in the file because of budget and availability. Just check it out. I have one question: Do I need to sterilize filtration base by autoclave every time before use as I am working for microbiological work?

Thanks in advance.

its sample you may use nylon membrane filter(0.2) paper. it is good and trap even small size of microorganisms