Notes on Some Protozoa and Zooplankton of Sewage Systems in Kolkata

Sewage is water carried wastes, in either solution or suspension, that is intended to flow away from a community. It is more than 99. 9% pure water and is characterized by its volume or rate of flow, its physical condition, its chemical constituents and the bacterial organisms that it contains. Sewage water is a complex matrix with many distinctive chemical characteristics. These include high concentrations of ammonium, nitrate, phosphorus, high conductivity (due to high dissolved solids), high alkalinity, with pH typically ranging between 7 & 8.