This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Activated Sludge . This is an upgraded version of en Aerated Sludge which was uploaded by Kekel on July The reasons for upgrading the image are To convert the lossy which already has visible artifacts to the nonlossy format To shorten the width of the image from px to px so that it can placed on the right side of article