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Industrial Case Studies

Hovensa L.L.C., St. Croix, Virgin Islands - USA

HOVENSA L.L.C. operates one of the most modern refineries in the U.S., and one of the largest in the world.

Source: Wastewater from refinery operations

Key Technology: Biological treatment in an activated sludge system
Commission Date: Second Quarter 2008
Contract: Design-Build

Key figures

2,440 gpm average flow
4,040 gpm peak flow

Veolia Water Technologies is dedicated to providing solutions for the specific challenges of water and wastewater treatment in the oil and gas industry.

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The client

The facility is a jointly owned subsidiary of Hess Corporation and a subsidiary of Petroleos de Venezuela, S. A.

Client's Needs

The Hovensa refinery was treating wastewater in three lagoons at the site. Although the wastewater treatment was effective, the U. S. EPA required the facility to either line the lagoons or install aboveground treatment facilities to eliminate the potential for groundwater contamination.

Hovensa chose to install aboveground facilities through a Design-Build contract with Veolia Water Technologies assuming full responsibility for the process guarantee.

Our solution

The new aboveground facility eliminates the use of in-ground aerated lagoons for treatment of wastewaters from the Base Refinery and has the capacity to handle the wastewater from the Fluid Catalytic Cracker (FCC) complex, which was previously treated in a separate aboveground system.
In addition to process wastewaters, spent sulfidic caustic will be treated in the biological system, providing substantial savings in disposal costs.

The Design-Build contract included design engineering, equipment procurement, construction and performance demonstrations.

Unique features of the new system are the operational flexibility integrated into the design and the innovative reuse of existing facilities. The new system will provide the options of continuing separate treatment of FCC wastewater for reuse as service water, or processing the entire flow through the new treatment trains to facilitate maintenance activities. Much of the equipment in the existing aboveground system will be reused, but for different purposes in the new design.

Solutions & Technologies

Major components of the wastewater treatment plant are:

  • Air coolers for the Base Refinery wastewater
  • Equalization
  • Sulfide oxidation
  • Early warning system for toxicity and shock loads
  • Activated sludge system with nitrification
  • Jet aeration systems
  • Multimedia filters
  • Post-aeration tanks

Process Flow Diagram

Hovensa Diagram