SeHAWK® 500 GPM Demonstraton for Iron Mine
A Midwest iron mine contains selenium-impacted waters as a result of mining operations. As a effort to ensure regulatory compliance and future mine operations, Frontier Water was selected by the customer to demonstrate treatment of the stream using a SeHAWK® Mobile bioreactor. With prefabricated construction and small footprint, the Mobile bioreactor allowed for aggressive delivery timeline and easy onsite installation of the treatment demonstration. Throughout the project’s duration, the SeHAWK® Mobile equipment met and exceeded treatment targets for selenium as well as other contaminants, at water temperatures as low as 40°F.
High Flow Selenium, Nitrate, and Metals Treatment at Western Limestone Quarry
Frontier Water systems has designed and built two SeHAWK® plants at a western limestone quarry, both of which accomplish dewatering and treatment of flows required to maintain mining operations in the pit. Built in 2018, the second plant has a capacity of 1200 gpm and contains two SeHAWK® modular bioreactors in conjunction with ultrafiltration and reverse-osmosis equipment to attain high flow treatment with a reduced footprint.
SeHAWK® 2000 gpm Selenium Treatment Plant
A phosphate mine in Idaho has a 2000 gpm groundwater stream contaminated with selenium that must be treated prior to discharge. To minimize plant footprint, Frontier Water Systems integrated ultrafiltration (UF) and reverse-osmosis (RO) processes in conjunction with two SeHAWK® modular bioreactors. This innovative UF + RO + Bioreactor treatment configuration achieves high rate selenium removal from the stream, with the added benefit of an RO permeate stream to dilute the treated brine stream, allowing for contaminant removal to ultra-low levels. The plant has been fully operational since 2017 and continues to meet selenium discharge requirements for the customer.
SeHAWK® 250 gpm Selenium Treatment Plant
To mitigate the impact of mining operations on a local wetland, a Western US mine must collect and treat a selenium contaminated groundwater stream prior to discharge. To deliver environmental compliance without a large footprint or construction effort, Frontier Water Systems supplied a modular SeHAWK® bioreactor along with auxiliary plant equipment, housed inside a 2000 sq. ft tent structure. Commissioned in 2015, the selenium treatment plant has operated continuously by Frontier Water field engineer staff to maintain high rate selenium reduction to >95% removal.
SeHAWK® 500 gpm Selenium Treatment Plant
To maintain mining operations at a limestone quarry in California, the mine operator must continually dewater the open pit and treat the stream for selenium and nickel prior to discharge. The first of two plants, a 500 gpm facility was designed and built in 2014 under an expedited timeline. The compact footprint, modular plant was built within the confines of the mine pit, requiring only a level gravel surface for installation. Since installation, the SeHAWK® bioreactors have been operational to achieve a stringent discharge limit of 4 ppb selenium.
Denitrification in Municipal Drinking Water
Frontier completed a pilot study at a western municipality for nitrate removal from the city's drinking water supplies. The city owns and operates a reverse osmosis (RO) plant for treatment of hardness and nitrate in the city water supplies. Changes to their discharge permit will necessitate nitrate treatment and reuse the brine stream produced from the RO. Using an expanded bed, upflow bioreactor, FWS successfully demonstrated full and efficient denitrification from concentrations that reached 72 mg/L nitrate as N in the RO brine stream and post treatment to meet EPA standards for drinking water. Results from the successful pilot study lead to preliminary design of a full scale 1.67 MGD RO brine treatment plant for the city.
SeHAWK® 240 gpm Municipal Brine Turnkey Plant Installation
A western US municipality operates a reverse-osmosis drinking water plant that produces a brine stream with elevated selenium and nitrate. In order to comply with state regulations, the brine stream must be treated prior to being discharged to a local waterway. After completing a 2-month pilot study, Frontier Water Systems was selected to design and supply a treatment plant, centered around a SeHAWK® Link modular bioreactor. The SeHAWK® Link provides the customer with the flexibility for future expansion, a compact footprint, and easily integrates with the existing RO and various auxiliary equipment and treatment processes. Since startup, the SeHAWK® has consistently removed nitrate to below detection limits and has removed selenium to below the stringent discharge limit of 4.6 ug/L. The success of the plant has enabled the municipality to attain greater independence of drinking water supplies, securing safe drinking water for current needs and future town growth.
SeHAWK® Pilot Demonstration for High Salinity Waters
To protect local ecosystems from selenium contamination, a water district in California operates a demonstration-scale plant for treatment of selenium in high-salinity natural waters. To test an upgrade to plant capacity and operation, Frontier Water Systems was selected to pilot the SeHAWK® process in conjunction with ultrafiltration and reverse-osmosis pre-treatment. Over four months of operation, the SeHAWK® process demonstrated selenium removal rates >95%. Despite changes in water quality, including spikes in feed nitrate concentration and TDS, the SeHAWK® pilot process achieved results that exceeded pilot goals. These results were achieved while operating at a contact time equal to 20% of other conventional biological treatment also tested on site.
Power Ash Pond
SeHAWK®Mobile 250 gpm Installation with Expedited Delivery
In May of 2018, an eastern power utility encountered an urgent need for a selenium removal system during the closure of one of their ash ponds. Frontier deployed a SeHAW® Mobile bioreactor which was deployed to site within 30 days of the order. While operational, the bioreactor experienced temperatures in the treatment stream as low as 35o F , and the system continued to reduce selenium below the required limits. Working in conjunction with an upstream absorbent media system, the system demonstrated compliance that could not have been met without the additional biological treatment.
SeHAWK® 250 gpm Eastern Ash Pond Closure
To comply with state and federal regulations, an Eastern US power utility required treatment for TSS, selenium, and other metals to properly decommission their coal ash water retention pond. The customer chose to purchase, rather than lease, a SeHAWK® Mobile bioreactor for future use at other sites. The SeHAWK® unit was operated under a wide range of conditions and temperatures with a wide fluctuation in influent concentrations. Under these variable conditions, the system successfully removed nitrate, selenium and other contaminants of concern enabled the complete closure of the ash pond in 2019.
600 gpm Leasable SeHAWK®and UF Equipment Package for Eastern Ash Pond Closure
To comply with state and federal regulations, an Eastern US power utility required treatment for TSS, selenium, and other metals to properly decommission their coal ash water retention pond. The customer selected a leasable, mobile equipment package which provided a small footprint without upfront capital investment. A SeHAWK® Mobile bioreactor was implemented for selenium and metals removal in conjunction with two 300 gpm mobile UF containers for overall TSS removal. Treating over 18 million gallons of ash pond water, the SeHAWK® and UF mobile equipment surpassed discharge requirements, enabling project completion more than 2 months ahead of schedule.
SeHAWK®FGD Blowdown 2x300 gpm Treatment Plant
After a SeHAWK® pilot study demonstrated effective treatment of FGD blowdown for selenium, nitrate, arsenic, and mercury removal, a 2800 MW southern power utility chose to install a full-scale SeHAWK® FGD bioreactor at the facility. The system was commissioned in 2019, with Frontier Water Systems personnel providing thorough onsite engineering presence to ensure the successful mechanical, electrical, and operational success of the bioreactor installation. Within two weeks of startup, the SeHAWK® FGD bioreactor demonstrated treatment performance to well below ELG standards.
SeHAWK® FGD 550 gpm Treatment Plant
An eastern power utility, and prior owner of a competing biological metals removal system, switched to the SeHAWK® FGD bioreactor for selenium, mercury, nitrate, and arsenic ELG compliance. The second of three plants for the utility, the SeHAWK® FGD installation is located at a 2000 MW eastern power plant and is designed for a flow range of 150-550 gpm. Since commissioning in 2018, the SeHAWK® has been online to deliver consistent compliance with ELG standards.
SeHAWK® 300 gpm FGD Treatment Plant
An eastern power utility, and prior owner of a competing biological metals removal system, switched to the EPA recommended SeHAWK® FGD bioreactor for selenium, mercury, and nitrate ELG compliance. As the first of three SeHAWK® installations for this client, is plant is located at a 2400 MW southeastern power plant. The installation is designed for a flow range of 100-300 gpm. The equipment was designed, built, and delivered to site 14 months after ordering, demonstrating the efficacy and benefit of Frontier Water System’s prefabricated approach.
SeHAWK® Pilot Demonstration of Shutdown Performance
A southern power utility evaluated a SeHAWK® bioreactor for selenium, nitrate, arsenic, and mercury removal of FGD blowdown water through a long-term pilot trial. This pilot trial included Frontier-provided iron co-precipitation pretreatment. The pilot demonstrated sustained, long-term, compliance with 2019 ELG standards. Additionally, the pilot underwent two, extended 5-week shutdowns to explore the effects on system performance, demonstrating effective recovery from each of these shutdowns.
SeHAWK® Pilot Demonstration of FGD Blowdown with high TDS and Chlorides
In 2016, a SeHAWK® pilot bioreactor was installed and operated at an Eastern Power Utility. The pilot system explored treatment of selenium, mercury, and other constituents in high TDS water. The pilot successfully removed selenium below ELG limits for the duration of the study with influent TDS concentrations reaching a maximum level of 38,000 parts per million. The pilot was operated with limited pretreatment and at a lower EBCT than a full-scale system which further demonstrates the capability of biological treatment and opens the door for the possibility of reduced capital expenditure in full-scale designs.
SeHAWK® Pilot Demonstration of Scalability
Three pilot demonstration units were installed at separate facilities for an eastern power utility. The objective was to explore the efficacy of the SeHAWK® two stage biological treatment system compared to other available technology. The results showed efficient and effective performance which resulted in the purchase of three full-scale systems; plant 1 and plant 2 successfully completed commissioning in early 2019. The full-scale results represent a strong performance link between full-scale and pilot systems.
SeHAWK® Pilot Demonstration of FGD Blowdown with Variable Pretreatment and High Influent Temperature
A pilot demonstration was installed at a state-run energy facility with feed from a single pass FGD system. Upon startup, the system explored the maximum biological operating temperature of 105°F. The system experimented with a wide range of pretreatment operational conditions to demonstrate the hardiness of the biological approach. The pilot produced results compliant with the EPA ELGs, despite varying influent conditions. The ultrafiltration unit demonstrated effective selenium polishing ability during this pilot as well, with a maximum additional removal up to 30 parts per billion.
SeHAWK® 50 gpm FGD Demonstration Scale Treatment Plant
After several SeHAWK® pilot studies showed successful treatment of FGD blowdown for selenium, nitrate, arsenic, and mercury removal, a southern power utility chose to install a demonstration scale SeHAWK® FGD bioreactor at one of their plants in the South Eastern US. The installation was completed in 2016, demonstrating FGD metals compliance below ELG limits. The system was restarted in October 2019 and continues to operate as a demonstration and R&D unit for the client.