How to block specific IPs in apache?

I am having a java based application running in tomcat. It is an online app, the request first goes to apache and then redirects to tomcat.

Today I was not able to log into my application and I noticed warnings at catalina.out file. They said "An attempt was made to authenticate the locked user "root" "and "An attempt was made to authenticate the locked user "manager" "

In my localhost_access_log.2015-07-07.txt I found the below IP addresses trying to access the system.

83.110.99.198
117.21.173.36

I need to block these 2 IPS from accessing my system. The first IP is a well known blacklisted according to the anti-hacker-alliance. How can I do this thing?

FYI I am using apache 2, so the main configuration file is apache2.conf

(Please don't remove the IP addreses I listed above, as I need other developers to be aware of the threat as well)