On SQL side in Content Database if you want to be sure and confirm deletion of the file you can use fallowing SQL .
1) Open SQL Server Management Studio 2) Select related Content Database and click “New Query” 3) Select * from All Docs where List ID='’ *** You can find List Guid on Browser Address bar when you open Library Settings page of a document libarary.
The default value is 30 days orphan_scan_period: Specifies the minimum amount of time that must pass between two orphan cleanup garbage collection runs.
The default value is 30 days garbage_collection_time_window : Specifies the minimum time that must pass between identifying a blob as having no references in the database and deleting the blob from the store.
In that kind of systems as a manner of being on the safe side they are just mark the files are deleted and than runs some background process later for deleting files according when some thresholds or limits are exceeded.
In that Point you have two option to bypass this feature that 1) you can totally disable Recycle Bin from Central Administrations site by CA- on Ribbon Menu Select General Settings and set “Recycle Bin” property as “Off” 2) or when you delete a file you can clear Site (First-stage) and Site Collection (Second-Stage) Recycle bins.Usually this is not a problem it is by design issue , because purpose of data recovery ,performance consideration, data integrity and safety the deleted files in real are not deleted immediately.So many systems are designed like this as Share Point and also RBS included.and check results for the file still is exists in that list .If you clear correct there should not be the related file is present on the results.