Selenium Water Treatment

Cutting-edge selenium water treatment options

The most highly effective selenium water treatment for applications ranging from coal and metals mining, refining, power generation, agriculture and more is accomplished using our patented fluidized bed bioreactor technology (FBR) technology. The FBR has shown to have ‘best in class’ performance in the coal mining industry for larger outfalls – cost effectively removing selenium to below 5 ppb, even with multi-contaminant wastewaters.

Alternatively, our high-efficiency ion exchange technology can be tailored to hard-to-treat waste streams containing selenium, offering high removal rates, cost efficiency, low waste rates and ease of operation with a small footprint.

Selenium treatment can also be accomplished using Envirogen’s Advanced Metals Removal System, which features Zero Valent Iron media.

The selenium dilemma

In the United States and Canada, the issue of selenium discharge (in its many forms) into the environment is becoming a matter of increasing concern. The U.S. Environmental Protection Agency has added selenium to its list of National Resource Water Quality criteria with a recommendation of 5 µg/L. Several states have followed with enforcement actions at this same low level. In Canada, an interim criterion of 1 µg/L has been established as a Canadian Water Quality Guideline, and 2 µg/L in British Columbia.

Envirogen Solutions to Selenium

Envirogen Technologies offers a technology portfolio designed to respond to the selenium treatment requirements of mining, power generation, refining, agricultural and groundwater applications.  Envirogen’s team works with consulting firms and directly with facility engineering teams to adapt these technologies to meet the needs of a specific treatment application – and can provide design, build, permitting and operating expertise as required, providing guaranteed performance and guaranteed costs over the life of an installation.

Fluidized Bed Reactors

Best-in-class performance for high volume, high concentration clean-up
Envirogen’s patented fluidized bed reactor (FBR) biological treatment technology has been proven as a ‘best in class’ approach for handling large flow rates of selenium-containing wastewater, with low capital and operating costs, and over a wide range of influent and discharge limit conditions.

The FBR technology has a long track record of providing high removal rates with the low cost of operation and “green” benefits typical of biological treatment systems. The advantages of employing an FBR in a selenium treatment application include an ‘order of magnitude’ cost advantage in system design and installation compared with other commercially available technologies. This is due to smaller system footprints as well as the ability to manage issues such as suspended solids and waste disposal in a much more effective fashion over a broad range of influent flow rates.

The FBR works by utilizing project-specific media and electron donors, operated upflow in an anoxic state. Selenite and selenate are reduced to insoluble selenium that is removed along with biomass and feed suspended solids by downstream liquid/solids separation (usually filtration). This fluidized bed allows for very high biomass concentrations and consistent performance. The removal of excess suspended solids and biomass from the fluidized bed is accomplished with Envirogen’s patented biomass control and in-bed cleaning systems. Combining a high concentration of biomass with plug flow allows Envirogen FBR systems to achieve extremely low effluent selenium levels on a consistent basis.

Proven technology in coal mining applications
Envirogen’s FBR technology has demonstrated the ongoing ability to achieve <4.7 µg/Lselenium consistently for a 2800 GPM mining operation. Envirogen is an industry leader in the use of bioreactor technology, with over 200 systems installed in the United States.

Further reading on FBR in selenium applications:
Review of Available Technologies for the Removal of Selenium from Water ( prepared for the North American Metals Council)
Startup and Commissioning of a Full-Scale Selenium Treatment Facility For Mine Water Treatment
New Options for Treating Selenium in the Coal Industry

Advanced Metals Removal System (AMRS)

Envirogen Advanced Metals Removal System featuring Zero Valent Iron (ZVI) technology is another option to remove Selenium and can be operated as the sole treatment.

Zero Valent Iron media delivers high removal efficiencies allowing customers to comply with stringent wastewater discharge permit limits. A recent pilot study for treatment of coal ash pond water has demonstrated the effectiveness of the AMRS to reduce selenium levels to single digit parts per billion, even when faced with the more difficult-to-treat species such as selenate.

High-Efficiency Ion Exchange

Ideal for lower concentrations & remote locations

Envirogen’s patented High Efficiency Ion Exchange technology offers treatment solutions that can be highly tailored to variable waste stream compositions and overall treatment system configurations.

Our High Efficiency Ion Exchange process is based on a patented system design that addresses many of the challenges seen in real world selenium removal applications. These systems are capable of removing selenium to very low levels (< 5 µg/L) – cost effectively. In addition, they have the advantages of a small footprint and automated operation, making them ideal for space restricted treatment facilities and remote locations.

Envirogen’s proprietary multi-bed system configurations offer faster kinetics and long media life while meeting a wide range of volume requirements. We employ remote monitoring and communication capability to enable our customers and field service technicians to ensure proper performance and attend the unit as needed.

Envirogen offers high-efficiency ion exchange systems with low capital investment options and pay-for-performance guarantees over the lifetime of the installation, creating the best opportunity for an optimized lifecycle cost.