Suman Bhat, I will try your way. Mihail Iliev, I have tried with 121/20' but still there was contamintion and one more thing my concentration is 50 g/L and i am using commercial grade CaCO3. Andrei Nikonov, I am using higher concentration so filteration wont work properly (CaCO3 is less soluble).
Daer Kunal Garg, Yeah for microbial growth media. Final I found solution: Autoclaving it for two time. 1. Dry CaCO3 sterilized and then add in media, 2. it will be autoclave with media as second time.