Many jurisdictions are tightening their water quality regulations for sulphate, driving the need for compliance in industries like mining, metal processing, pulp and paper, sewage treatment, and chemical manufacturing.

In mining, most metals are won from ore bodies containing sulphide minerals that contain sulphur which is converted to sulphate during the extraction process. Furthermore, sulphur-containing reagents such as sulfuric acid are often added to the metal extraction process. Consequently, large amounts of sulphate are typically present in mine and/or metal extraction and refining wastewaters.

Historically, sulphate in water has not generally been subject to regulation. However, with the increasing realization that global water resources are limited and are declining as the population grows and consumption increases, stricter regulations on water quality are being imposed to allow its re-use or safe disposal into the environment. For sulphate, this has meant the introduction of water quality regulations in a number of jurisdictions worldwide to respond to the need to protect the health of humans, domestic animals, agriculture, and the fauna and flora in the environment.

Sulphate is also a concern in process waters as it forms scale on process equipment. Failure to deal with the sulphate issue can increase costs significantly due to reduced volumetric capacity, reduced metallurgical performance, increased downtime for mechanical de-scaling and premature equipment failure.

BioteQ's proprietary Sulf-IX^TM ion exchange technology removes sulphate from wastewater and process effluent, producing gypsum and clean water that can be discharged safely to the environment. Gypsum is an environmentally benign product commonly used in fertilizers and building products. Click here for more information about Sulf-IXT.

In the mining industry, BioteQ's Sulf-IXT technology has a number of potential uses including:

• Removal of sulphate from lime plant effluent to meet new environmental discharge regulations.
• Removal of sulphate from contaminated surface waters and groundwater for process use or discharge to the environment.
• Treatment of process waters to allow recycle and recirculation of water within a process to reduce or eliminate the risk of scaling of process equipment.

BioteQ is currently piloting its Sulf-IXT technology at several sites, and is in the design and engineering stage for its first commercial plant.

Available competing processes for reducing sulphate concentrations include membrane technologies (e.g. reverse osmosis), processes based on "ettringite" formation (e.g. SAVMIN and CESR), biological sulphate reduction and precipitation with barium. Typically these technologies are either not able to treat contaminated water to a level which complies with new regulations and standards that are being imposed on industry or suffer one or more technical disadvantages. They also tend to have higher capital and operating costs than BioteQ's Sulf-IXT technologies and have limited application for water treatment in the some industries, without significant additional front-end and back-end process modifications.

• BioteQ's process is less expensive both in initial capital and on-going operating costs.
• BioteQ's process produces only clean gypsum and water; there are no additional waste products requiring additional process steps or requiring special disposal. Clean water recovery is therefore very high.
• BioteQ's process has robust chemistry and can deal with the presence of solids
• BioteQ's process has low power consumption.
• BioteQ's process can efficiently handle scaling issues, particularly relevant to the treatment of lime plant effluents.