निम्नलिखित में से किस प्रवाह को सेनेटरी सीवेज (sanitary sewage) भी कहा जाता है?

In the very first stage of decomposition of the organic matter in sewage:

The secondary treatment of sewage is primarily caused by:

Which types of bacterial forms are present in larger numbers in trickling filters compared to the activated sludge process?