Blockchain has various merits such as decentralization, greater transparency and improved traceability. Nowadays blockchain is used at various numbers of applications such as financial related services, business & industry, integrity verification, governance, health and education sectors. Even though the blockchain technology has promising approaches for the building the future of internet systems and also extensive research is going on about the technical challenges. In this paper we presented the comprehensive survey on blockchain and the techniques that can be used to address the scalability issues with respect to storage and also different privacy preserving techniques that can be incorporated during the implementation of blockchain application.