Enhancement of Food Production — BIOLOGY STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYEnhancement of Food Production4 Marks
Question
Microorganisms in sewage.
✓
Answer
$1.$ Sewage contains pathogenic bacteria, viruses, fungi, protozoa which cause dysentery, cholera, typhoid, polio and infectious hepatitis, etc. It also contains nematodes and algae.
$2.$ Their number and type of microorganisms in sewage depends on the composition and source of sewage.
$3.$ Millions of bacteria per ml may be present in raw untreated sewage.
$4.$ Bacteria in sewage include coliforms, fecal Streptococci, anaerobic spore forming bacilli and other bacteria found in the intestinal tract of humans.
$5.$ The sewage also contains soil bacteria.
$6.$ During sewage decomposition, initially aerobic and facultative anaerobic organisms predominate which are followed by strict anaerobic especially methogenic bacteria that produce methane $(CH_4)$ and $CO_2.$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.