Typically preliminary treatment consists of:

  • Headworks pumps
  • Screens

In industry, preliminary treatment is very common as a first line of treatment that they can easily be installed. It does not require chemicals or complicated mechanical parts and it has the potential to reduce high strength charges. Many utilities charge for biological oxygen demand (BOD) and total suspended solids (TSS) and screens have the ability to reduce the amount of BOD and TSS in effluent waters.

Headworks Represented by Red Circle Above

Headworks Pumps
  • These pumps are used to lift wastewater to plant inflow elevation, generating hydraulic head used to assist water flow through the plant.
  • Not many opportunities here 
  • Typically very large screw pumps
Screening
  • Screens remove large objects often refereed to as "rags." Typically mechanically scraped bar screens are used.
  • Used to remove large solids
  • Coarse or fine screens can be used with different advantages and disadvantages
  • Material removed during screening will often be ground and disposed of in a dumpster

This is an example of a screen used in a vegetable processing facility.