Application for removing watermark from pdf

Hi guys, I have several pdf files which have watermarks on each page. It is quite annoying as the watermarks are large, and it covers about 1/3 of the page and some of the texts. Do you guys know any application in mac that can help me remove those watermarks in those pdf files.

I know adobe photoshop can do the job but it's quite complicated to remove the watermark from each page separately, especially when the pdf file consists of several thousands pages . I want the application that can help me finish the task with a few clicks of the buttons. Thanks