If you want to embed tweets in your blog or website from a @username but only show those with a given #hashtag, Twitter’s Widgets makes it easy:
For example, to show only tweets from my @allotmentor account which are tagged with #allotment, I simply enter
from: @allotmentor AND #allotment
in the Search Query box on the Configure a search widget page. Then copy and paste the generated code into your site. See it in action here.
Thanks to this answer on Stack Overflow