Are personality clashes with other faculty a valid reason to deny tenure Assume the tenure track faculty members has produced worthwhile and well published research, has shown potential to attract outside funding and has above average reviews for classroom instruction.

Is the mere fact that this person treats other faculty members (not students) with varying levels of hostility, is generally uncooperative and largely disliked by department faculty enough to deny tenure?

The positives are pretty strong and I would normally assume they would be sufficient but I am concerned that other department faculty could strongly disagree and some may even choose to seek employment elsewhere if he is granted tenure.
In practice, "collegiality" is often a consideration in tenure decisions, whether or not it is a factor identified in the university policy on tenure and promotion.  

The American Association of University Professors (AAUP) has come out with a statement against the use of collegiality as a an explicit factor in tenure decisions:

http://www.aaup.org/report/collegiality-criterion-faculty-evaluation/ 

However, this report also makes it clear that a faculty member who is hostile to the other faculty in his/her department would typically not be doing an adequate job in service and teaching, because working with colleagues in these areas is a necessary part of the job.  

Thus "We're not granting tenure to John because no one likes him" wouldn't be a good reason, while "We're not granting tenure to John because he doesn't work productively in departmental committees" would be a reason to deny tenure.  

As a practical matter, if the tenured faculty in the department don't like you and don't want you to get tenure, they'll probably find an excuse to deny you tenure.  Any tenure track faculty member would be well advised to get along with the other faculty in the department.