# Calculation of Normality

## Calculation of Bacterial Density

Calculation of bacterial density.

The determination of indicator bacteria, total coliform, fecal coliform, and fecal streptococcus or enterococcus is very important for assessing the quality of natural waters, drinking-waters, and wastewaters.

The procedures for enumeration of these organisms are presented elsewhere (APHA et al., 1995).

Examinations of indicator bacterial density in water and in wastewater are generally performed by using [....]

## Waste Water Treatment

1.What is Waste water

“Wastewater,” also known as “sewage,” originates from household wastes, human and animal wastes, industrial wastewaters, storm runoff, and groundwater infiltration. Wastewater, basically, is the flow of used water from a community. It is 99.94% water by weight.The remaining 0.06% is material dissolved or suspended in the water. It is largely the water supply of a community [....]

## Calculation of Total Dissolved Soilds(TDS)

Calculation of Total Dissolved Solids (TDS) of given water sample.

Apparatus:

Oven, desiccators, filter paper, pipettes.

Procedure:

* Heat clean dish for 1hour in an oven

* Store in desiccators and weigh immediately before use.

* Stir the sample and pipette a measured volume onto a glass fiber filter.

* Wash with three successive 10ml volumes of reagent [....]

## Calculation of Normality

Calculation of Normality

Equivalent weight (EW) = Molecular weight (MW) / Valency (Z)

Normality (N) =Equivalent weight (EW) / Volume of Solution (1000 ml.)

Meq = Actual weight (W) / Equivalent weight (EW)

Example: Molecular wt of K2Cr2O7 is 294.148 gm

Valency = 6 (because of Cr -6)

EW = 294.148/6 = 49.025 [....]