ZLS™ is an alternative produced water treatment process promoted by Eco-Tec for SAGD (Steam Assisted Gravity Drainage) boiler feed water in the production of heavy oil, most typically in Western Canada.

The process eliminates the need for the traditional practice of lime softening and its associated costs, large site footprint and operational challenges as a part the treatment process.

Technical validation of the process has been done and similar systems have been in commercial operation in heavy oil production in California for many years.

Diagram of the Produced Water Treatment for the SAGD operations

Eco-Tec’s incorporates the following products into a ZLS process:

Spectrum Plus Filter™ to effectively remove oil and suspended solids to low levels as a pre-treatment to the RecoPur® ion exchange softeners RecoPur® Softeners (ion exchange) include various configurations of strong and weak acid resins which are brine-only regenerated and produce exceptionally low treated water hardness with low chemical costs.

OTSG Blowdown Treatment which removes silica from OTSG blowdown as a filterable solid to facilitate disposal or recycle of the water.

Proposed ZLS Flow Sheet


  • OPEX reduction of 30-70% compared to current practices.
  • Simple design, fewer pieces of equipment to operate and maintain.
  • CAPEX for the water treatment at the Central Process Facility may be reduced by more than 30% due to the skid-mounted construction and compact footprint.
  • Based on similar, proven Eco-Tec softening systems which have been in operation at multiple sites in heavy oil produced water processing in California for over 6 years.