timeout - TIME_WAIT Info (reduce)

I have a ajax application that makes a request every 3 seconds, the requested page sets the header to (header("Connection: Keep-Alive, close");) then performs a database query and returns the latest data.

The value for TIME_WAIT is 60 seconds, so even tough I close the connection in my requested page(i.e "Connection: Keep-Alive, close"), the connection seem to be present for the next 60 seconds (this occurs for every Ajax request that I make), so for 1 minute 20 requests are made and total TIME_WAIT for that IP seems to be around 20

Is it possible to reduce the TIME_WAIT to say 15 seconds, to reduce the overall TIME_WAITS or is it possible to force a connection close after every Ajax request

Any help will be appreciated

Thanks