Upload date
All time
Last hour
Today
This week
This month
This year
Type
All
Video
Channel
Playlist
Movie
Duration
Short (< 4 minutes)
Medium (4-20 minutes)
Long (> 20 minutes)
Sort by
Relevance
Rating
View count
Features
HD
Subtitles/CC
Creative Commons
3D
Live
4K
360°
VR180
HDR
388,615 results
During the secondary treatment of sewage, bacteria are used to reduce nutrients in the wastewater. This occurs in the activated ...
55,491 views
8 years ago
Wastewater treatment involves the removal of impurities from wastewater, or sewerage, before they reach aquifers or natural ...
1,289,576 views
4 years ago