email – Postfix Mail Server – Slower Queue Processing

I m using postfix as email server for processing bounce emails.
I’ve got around 8000 emails in my queue and I’ve noticed longer delay periods for processing an email. This is my mail log

Jul 13 09:13:46 mod postfix/local(31036): 2CE2E81C91: to=<>, orig_to=<>, relay=local, delay=88614, delays=88488/59/0/67, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME)
Jul 13 09:13:52 mod postfix/local(31035): 423DA820A5: to=<>, orig_to=<>, relay=local, delay=88771, delays=88640/40/0/91, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME)
Jul 13 09:15:04 mod postfix/local(31035): E8D5F8314F: to=<>, orig_to=<>, relay=local, delay=57443, delays=57239/131/0/73, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME)
Jul 13 09:15:05 mod postfix/local(31036): A0674822AB: to=<>, orig_to=<>, relay=local, delay=55018, delays=54814/126/0/79, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME)


alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
allow_percent_hack = no
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = yes
compatibility_level = 2
home_mailbox = Maildir/
inet_interfaces = all
inet_protocols = all
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
mailbox_size_limit = 0
mydestination = $myhostname,,, , localhost
myhostname =
mynetworks = (::ffff: (::1)/128
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relayhost =
sender_bcc_maps = hash:/etc/postfix/bcc
smtp_tls_security_level = may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
virtual_alias_maps = hash:/etc/postfix/virtual

Is there any way to make queue processing faster? I m a newbie at this, so any help would be usefull.

Note: I m using 2GB RAM server and postfix installed through virtualmin