Creating Values

Zero Water Waste Treatment


The Wastewater Treatment Plant collects various wastewater streams from within the refinery and segregates them into one of three classifications.

The three different classifications of wastewater are:

  • Accidentally Oil Contaminated (AOC),
  • Continuously Oil Contaminated (COC),
  • and Process Wastewater.

Wastewater from all three systems is treated in three stages to recover the water for reuse within the refinery.

  • Primary treatment includes various oil separation units like API, CPI and DAF.
  • Secondary treatment includes Activated Sludge Treatment and clarification.
  • Effluent from the secondary treatment will be further treated in Zero Liquid Discharge (ZLD) system (Reverse Osmosis and Brine Concentrator) to meet the quality required for cooling water makeup.

Waste sludge collected from all systems will be dewatered and incinerated. Recovered Oil will be transferred to the wet slops system. Concentrated brine from ZLD system will be transferred to evaporation ponds.

  • The COC system is also s gravity flow system that collects wastewater from crude tanks bottoms, intermediate tanks bottoms, product tank bottoms and oily water drains in utility units.
  • The streams normally sent to this system are non-ISBL process oily water drains such as bundle cleaning area, maintenance building drains, blow down from Unit 78 Cooling Tower.
  • All COC wastewater will be pumped to API separator for the treatment.
  • Process Wastewater consists of streams like Desalter effluent and excess stripped sour water. These streams are collected and transferred to the wastewater treatment unit by pressured above ground piping.

The following streams of wastewater generated in various process and utility units will be transferred to the Unit 76 by above ground piping directly to the primary treatment.

  • Desalter Effluent with ARDS catalyst wash water
  • Excess Stripped Sour Water
  • Cooling Tower Blow down from U63
  • Cooling Water Side Stream Filter Backwash Water
  • Neutralized Waste From Demineralization and Condensate Polisher unit
  • Oily Sludge Centrate Water
  • Bio Sludge Centrate Water