triming on data submitting

Hi all,
In CI 3.1 I can use trim condition if I want to make checks without trailing whitespaces

PHP Code:

$this->form_validation->set_rules('email', 'email', 'trim|required|valid_email'); 


But that is only for validating.
If there are filters on data submitting/saving to remove whitespaces on enetered data, withoiut trim any field ?
Thanks!