The problem is that there is usually a lot of information contained in the paper in the form of the direction of the research the way the research is framed and the style of writing which may well tip off a reviewer who is familiar with the submitting author's work.
It is probably impossible to ensure true anonymity for the submitting author, all you can do is remove any explicit identification. Even with reviewers many people believe they can identify who has written some of the review comments they receive, they may be wrong of course but they believe they can.
Any specific individuals bias is at least attempted to be addressed by usually sending an article out to review by several people, say 3. 3 is a good number becasue then you are likely to get a majority view on the paper, and if 1 biased reviewer unfairly slates it there are 2 others to compensate and the editor can make a judgement based on all of the reviews. Biased editors may present rather more of a problem.
TTFN,
WK
™ Version 4.2
