Cyanide Wastewater Treatment

Multiple options for flows with cyanide

Cyanide in wastewater flows are treated in multiple ways, each with different advantages. Saltworks can help you understand your options and implement the solution that best suits your flow rate, concentrations, discharge limits, and other considerations.

Cyanide Uses and Risks

Cyanide is widely used in many industries and is an important precursor for many organic chemicals such as nitriles. In mining, cyanide is frequently used in the extraction of gold and silver. Cyanide also occurs in nature.


Wastewater containing cyanide is carefully regulated because many of its compounds are toxic. Fortunately, multiple treatment options are available.

Photo of a mining tailings pond-cyanide
A photo of a custom designed and built BrineRefine unit for a mining application

Treatment Technologies

Treatment options for cyanide include:

  • Granular activated carbon (GAC): absorbs cyanide, but can result in relatively high costs for both the GAC itself and its spent disposal. GAC is best suited for intermittent or seasonal cyanide flows.
  • High-pH bleach oxidation: destroys cyanide, producing safe nitrogen gas. Bleach oxidation is well-suited for permanent, continuous, cost-effective treatment.
  • Iron precipitation: uses ferrous sulfate to precipitate cyanide. Precipitation is also well-suited for permanent cyanide-laden flows.
  • Reverse osmosis (RO): used to produce safe-to-discharge freshwater with low contaminant levels. The highly concentrated reject is easy to transport for offsite disposal or treatment.

Your Treatment Strategy

Saltworks offers all of the above treatment technologies. The right solution for your process will depend on flow rate, concentration, consistency, required discharge level, and other water chemistry factors.


High-pH bleach oxidation and iron precipitation can be performed by BrineRefine, our flexible, automated chemical treatment system.


RO systems for cyanide treatment require specialized knowledge and plant configuration. Our advanced, ultra-high recovery XtremeRO, may be an option.


We can help you to consider these options and decide on what is best for you and your project. Contact us with your project details to learn more.

Photo of a Saltworks engineer inspecting a BrineRefine chemical reactor system used in the treatment of a specific ion of concern

Related Products

Photo of a full-scale, 2-module, Saltworks BrineRefine plant

BrineRefine Chemical Reactor

BrineRefine is a continuous stirred tank reactor (CSTR) that executes diverse chemical reactions efficiently and with precision.

Related Resources

Mine Water Treatment

Mining Wastewater Treatment

Saltworks provides comprehensive solutions for mining waters. We treat water, remove problem contaminants, achieve minimal liquid discharge (MLD) or zero liquid discharge (ZLD), and recover valuable metals as your project needs.

3D model of the phenol molecule structure

Removing Highly Toxic Phenolic Compounds: Wastewater Treatment Options

Excessive phenolic compounds are harmful to human health and the environment. Chlorophenols, by-products of chlorinating phenol-containing water, are carcinogens. A treatment system needs to be chosen and engineered carefully, with consideration of specific wastewater chemistry, operating conditions, and economics.

Photo of a periodic table representing the selective removal of specific ions in wastewater management

Selective Contaminant Removal

Targeting specific ions for removal can be the most cost-efficient way to treat a wastewater flow. Saltworks has treatment and sensing solutions available to treat ions and other species, making water suitable for discharge or re-use.

Photo of a Saltworks engineer inspecting a BrineRefine chemical reactor system used in the treatment of a specific ion of concern

BrineRefine ousts RO in a Mining Project

Our essential workers have done an exemplary job during the ongoing COVID-19 pandemic. Thanks to their efforts, we have shipped a full-scale, cost-optimized, targeted ion treatment plant to a USA Mining Client.