We made two environmental practicals in our first semester.

The first one is on sedimentation tank. The objective of this practical is to know the flow profile in the sedimentation tank and to know the performance of sedimentation. The procedure is to calculate the water capacity of the sedimentation tank from its dimension and to find the flow rate required to give an average residence time of 20 minutes. Equations used are

V=L*B*D

V=Qt

The second one is called filterability index. The objective of this practical is to remove suspended matter, rust, sludge, scale or algae from wastewater and to know other hazards may exist in the handling of biocides used to  disinfect the water. There are four procedures to calculate.

First procedure: The use of deep beds of porous granular media to filter liquids to improve their clarity is wideapread in municipal and industrial practice.

Second procedure: Predominant is the filtration of drinking water and industrial water although the filtration of sewage as a tertiary stage of treatment is increasing.

Third procedure: The filterability index apparatus utilized a bed of granular material normally sand but which can be chosen by the investigator.

Fourth procedure: The measurements taken with this apparatus enable a filterability number to be calculator which has significant in deep bed filter performance. Equation used is

F=HC/VCₒt