Elimination of extra steps and problems involved in the excavation of the disposals of screening (screened material) Often difficult to dispose highly polluted screenings - In USA if buried, 6 inches of cover material should be used

Screens can be classified on the basis of following criteria: Opening size: Coarse, Medium, Fine Cleaning Method: Manual, Mechanical, Raked, Water jet

It is the measure of the settleability and compatibility of sludge and is made from a laboratory column setting test. The sludge volume index is defined as ‘the volume in mm occupied by 1 gm of sludge after it has settled for a specified period of time’ generally ranging from 20 min to 1 or 2 hr in a 1 – or 2-l cylinder.

A typical solids analysis of wastewater, of the total solids, 50% is dissolved, 50% suspended. Of the suspended solids, 50% will settle. Industrial activity changes the composition of wastewater, often introducing toxic substances such as chromium and cadmium from plating operations. The typical composition of wastewater based on strength. The important characteristics

The Food to Microorganisms Ratio (F/M ratio) is a key parameter used in wastewater treatment processes to assess the organic loading rate and efficiency of the treatment system. It represents the ratio of the amount of organic food (measured as Chemical Oxygen Demand or Biochemical Oxygen Demand) entering the system to the quantity of microorganisms (typically measured as Mixed Liquor Suspended Solids or MLSS) present in the treatment process.