Sulfate Removal

Measure and treat sulfates in water flows

Many industrial processes produce or depend on sulfates. Sulfates can be regulated in some discharges and require cost-effective management. Saltworks can help you to monitor and moderate sulfate levels in wastewater flows.  

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Sulfate Challenges

Sulfates are of concern in many processes e.g. mining, oil & gas, fertilizers, and more. Although not generally very dangerous to humans, high sulfate levels can be regulated to protect the environment. Sulfates can be targeted for removal, without needing to treat all dissolved mass in an entire flow. Targeted treatment saves money. 


For seasonal sulfate challenges, chemical precipitation treatment may keep capital investment low, with chemical addition operating costs for only part of the year. If the challenge is year-round, and there is a low-cost disposal option for a sulfate rich brine, sulfate-rejecting membrane solutions may make more sense. We can help you to make informed choices with economics for all options.

FGD coal power plants
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Robust Sensors

Measuring sulfate ions in real-time enables targeted treatment and process optimization. Saltworks can provide automated, real-time sensors for sulfate ions. This live data can then be used to optimize a sulfate treatment process through:

  • Bypassing a portion of the flow around the treatment plant, and blending to meet a treatment goal
  • Treating to the right level, and not over-treating, resulting in excessive chemical waste, sludge generation, or brines

ScaleSense sulfate sensor was specifically developed to work with the toughest waters including high total dissolved solids (TDS) >50,000 mg/L. 


Sulfates can be precipitated by adding low solubility counter ions such as barium or calcium. Our BrineRefine system performs chemical precipitation in a smart, automated way to prevent overdosing. If inlet water chemistry changes, so does chemical dosing. BrineRefine enables smart selective precipitation and is:

  • Automated with simple solids management, avoiding coagulation, flocculation, and large clarifiers.
  • Free of coagulants or flocculants; no chemicals are added that could foul a downstream RO.
  • Compact: BrineRefine eliminates the need for large reaction vessels and clarifiers.
  • Designed for modularity, factory-built in ISO container skids of ~600 m3/day capacity per skid, with built-in redundancy and scalability by adding more skids (e.g. 3 skids × 600 m3/day).
  • Larger capacity (e.g. 10,000 m3/day) site-built units are available, in which incorporating site ponds as treatment reactors further reduces capital costs. 
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Reverse Osmosis System

Membrane Solutions

Nanofiltration (NF) is a cousin of reverse osmosis (RO), which rejects multivalent ions such as sulfates, while allowing monovalent ions to pass through. This limits total dissolved solids (TDS) mass load in the brine and can save brine management costs. Saltworks provides intelligent NF or RO sulfate treatment solutions in our XtremeRO product family—and also provides solutions for liquid reject.

Sulfate Removal Related Products

BrineRefine Chemical Softening System

Smart, compact, modular chemical system that reduces costs with precise dosing and built-in solids management. Improves recovery & minimizes fouling risk with intelligent controls that communicate with downstream assets, like RO or evaporators. More ...


An automated, real-time sensor for saline water that measures calcium (Ca2+), barium (Ba2+), sulfate (SO42-) ions and silica (SiO2). ScaleSense is robust and corrosion-resistant and functions accurately and precisely, even at extremely high-TDS. More ...

SaltMaker ChilledCrys Chilled Crystallizer

ChilledCrys concentrates water, extracts solid salt, and repeats the cycle using a novel UHP-RO system. By avoiding the use of evaporation, it achieves zero liquid discharge with considerable energy efficiency savings. More ...

XtremeRO Brine Concentrator

Next-generation water-maker and brine-concentrator based on reverse osmosis that achieves extreme freshwater recoveries, enabling cost-effective brine management and treatment of challenging organic-laden waters including oil & gas produced waters. More ...

Sulfate Removal Related Resources

BrineRefine modern chemical softening and treatment

SulfateSelect Sulfate Extraction System

SulfateSelect removes sulfates from wastewater, in some cases without brine by-products, thereby removing the expense of brine management. We offer a suite of sulfate processes, leveraging industrialized unit operations, arranged for cost effective and intelligent optimized operation.

Sulfates Selective Removal

Sulfate Discharge: Measurement and Cost-Optimized Removal

There are many sulfate treatments available, with different advantages and disadvantages. Factors for consideration include capital and operational costs, solid vs. liquid brine reject for disposal, if the need is seasonal or year-round, and suitability for adverse operating conditions.

real-time sensors analyzers scaling ions

Real-Time Sensing and Process Control: Introducing ScaleSense

Real-time measurement provides prompt feedback for controls. A real-time sensor can help to optimize your process, reduce risk, and minimize operational and maintenance demand. Saltworks has developed a new real-time sensor—that is simple and robust—to operate in the high-TDS range.

Comparison of FGD wastewater, one container is brown, murky and the second is clear water.

Flue Gas Desulfurization (FGD) Wastewater Pilot Test Results

Saltworks completed an off-site FlexEDR Selective pilot test to treat flue gas desulfurization (FGD) wastewater from a coal fired power plant in China. The objective was to reduce chlorides such that the FGD wastewater could be internally recycled and final treatment costs reduced notably.


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