What is the difference in how they are handled?
Specifically, why is it common to find Python used in production-level long lived applications like web-servers while PHP isn't given their similar efficiency levels?
PHP was designed as a hypertext scripting language. Every process was designed to end after a very short time. So memory management and GC basically didn't matter.
However the ease and popularity of PHP have invoked its usage in long lived programs such as daemons, extensive calculations, socket servers etc.
PHP 5.3 introduced a lot of features and fixes that made it suitable for such applications, however in my opinion memory management was of lower significance on that matter.
PHPs error management is quite good now, but as in every programming language that I know of you can produce memory leaks.
You still cannot code in the same style that you can code Java or Python applications. A lot of PHP programs will probably show severe problems where Java/Python do not. 
You can characterize this as "worse", but I would not. PHP just is a different set of tools that you have to handle different. 
The company I work at has a lot of system programs and daemons written in PHP that run like a charm.
I think the biggest caveat for PHP when it comes to as you describe "production-level long lived applications" is its multi-processing and threading ability (the 2nd is basically nonexistent). 
Of course there is the possibility to fork processes, access shared memory, do inter process communications and have message queues and stuff. But Python is far ahead on that matter, because it was designed bottom up for jobs like that.
How is memory management in PHP different from that in Python?