Pre-treatment removes materials that can be easily collected from the raw wastewater before they damage or clog the pumps and skimmers of primary treatment clarifiers. The in-fluent sewage water is strained to remove all large objects carried in the sewage stream.
Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float on the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment.
Secondary treatment is typically performed by indigenous, waterborne micro-organisms in a managed habitat. Secondar y treatment may require a separation process to remove the microorganisms from the treated water prior to discharge or ter tiary treatment. Secondary treatment removes dissolved and suspended biological matter.
Tertiary treatment is effected by sand filters, mechanical filtration or by passing the efuent through a constructed wetland such as a reed bed or grass plot. Tertiary treatment is sometimes defined as anything more than primary and secondary treatment. Treated water can also be used for groundwater recharg or agricultural purposes.
PHASE 01: 50% in advance with Purchase Order
PHASE 02: 40% before dispatch of the material
PHASE 03: 10% during Testing and before Completion Phase