[oracle@service1 ~]$ sqlplus sys/WXHWXH AS SYSDBA

SQL*Plus: Release 11.2.0.4.0 Production on Mon Jul 2 14:00:02 2018

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Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> Show parameter recyclebin;
NAME     TYPE VALUE
------------------------------------ ----------- ------------------------------
recyclebin     string on
SQL> alter system set recyclebin='off' scope=both;
alter system set recyclebin='off' scope=both
                                  *
ERROR at line 1:
ORA-02096: specified initialization parameter is not modifiable with this
option

SQL> alter system set recyclebin=off;
alter system set recyclebin=off
                              *
ERROR at line 1:
ORA-02096: specified initialization parameter is not modifiable with this
option

SQL> alter system set recyclebin=off scope=spfile;
System altered.

SQL>