SULFATEQ™ removes sulphate to less than 300 mg/l and converts it into hydrophilic (non-clogging) elemental sulphur. In addition, it recovers valuable metals such as copper, nickel and zinc as marketable metal sulphides.

Lime treatment for sulphate removal no longer meets the authorities’ requirements for sulphate concentrations or total dissolved solids. Reverse osmosis and ion exchange do not completely solve the problem either. They merely concentrate the pollutants, whereas SULFATEQ™ converts the pollutants into a valuable product.

The typical range for the application of SULFATEQ™ is an influent sulphate concentration of 1,000-25,000 mg/l and a pH level of 2-8. SULFATEQ™ is used as a standalone installation or as the final treatment at a lime-gypsum plant.

The power of this technology lies in its ability to solve multiple problems with one installation: sulphate removal and simultaneous metal recovery.

Typical applications of SULFATEQ™

  • Effluent treatment in the metal industry
  • Wash tower acid treatment
  • Brine treatment of reverse osmosis in combination with metal recovery to increase overall water recovery
  • Acid mine drainage treatment in combination with metal recovery
  • Effluent treatment and metal recovery in the viscose industry for the removal of metal, sulphate and COD
  • Integration with lime neutralisation plant to improve the effluent, reduce total dissolved solids and reduce the sludge whilst improving the quality, resulting in less liability

Advantages of SULFATEQ™ over traditional/alternative methods for sulphate removal

  • Effective removal of sulphate to less than 300 mg/l
  • Use of intermediate product (sulphide and alkalinity) to recover metals or produce elemental sulphur
  • Removal of ions responsible for hardness (calcium and magnesium) to less than 100 and 4,000 mg/l respectively
  • Removal of acidity without consumption of neutralisation agents such as caustic
  • Applicable for stream that is pH-neutral (e.g. sodium sulphate solutions)
  • A safe process at ambient conditions
  • Better selectivity of metals, higher product quality
  • Removal of ’difficult’ dissolved metals such as manganese, selenium and thallium
  • A flexible, robust and proven process used in 15 years of full-scale installations
  • No noticeable release of smell
  • Reduced eco-toxicity of effluent

Working principle

The core of SULFATEQ™ is a two-step process. The first step reduces biological sulphate by converting it into dissolved sulphide in high-rate bioreactors. This bioprocess uses an energy source such as alcohol or hydrogen gas. The second step oxidises the sulphide to elemental sulphur with plain air and separates it from the liquid. An additional step can be added to the core processes for the recovery of valuable metals.

Related products: THIOTEQ™ for metal removal/recovery of effluent that contains low metal concentrations.