The httpd web server doesn't really have a way to control how much
resources a given virtual host can have or a user can request.

This module should be able to limit access to certain areas
of the website and to limit mailicious users

You will need to add the following line to /etc/httpd/httpd.conf:
LoadModule bw_module          lib{64}/httpd/modules/mod_bw.so

See mod_bw-0.7.txt for configuration