how to get string from database and how to explode it in codeigniter?

Here is my code i tried to explode string, but get some errors, i got string but i did not explode, Here i getting some erros,i cant understand it A PHP Error was encountered
Severity: Warning
Message: explode() expects parameter 2 to be string, object given
Filename: views/testing.php
Line Number: 65
Here is My code:

Code:

 <?php

                                   foreach ($test as $t)  
                               {
                                     echo  $user_rights=$t;
                                       $t=(explode(",", $t));                                  


                                   }

                                   ?>