Define sewage. What is percentage of impurities in sewage?

What is sewage?

Define Mass percentage

What is the role of microbes in sewage treatment?

A 0.276 g impure sample of copper ore is dissolved and Cu^(2+) is titrated with KI solution. I_(2) liberated required 40 mL of 0.1 M Na_(2) S_(2) O_(3) solution for titration. What is the % of impurities in the ore ?

MnO_(2) on ignition converts into Mn_(3)O_(4) . A sample of pyrolusite having 75% MnO_(2) , 20% inert impurities and rest water is ignited in air to constant mass. What is the percentage of Mn in the ignited sample ?

Define sewage. Explain the secondary treatment of sewage.

Make a list of impurities present in domestic sewage.