Our Technology

Gross-Wen Technologies uses its patented wastewater treatment technology, known as the revolving algal biofilm system (RAB), to cost-effectively address new wastewater permits that are being required at municipalities and industries.

The RAB system uses vertically oriented conveyor belts that grow algae on their surface. While the algae grows it “eats” nitrogen and phosphorus from the wastewater. It also uses Carbon Dioxide from the atmosphere and sunlight to rapidly grow algae biomass. The algae produced during this process is a revenue stream for our customers and can be used to make fertilizers, bioplastics, and biofuels.

We use nature
to solve problems.

Our system can be used for companies of all sizes. If you’re curious how we can serve the needs of your business or municipality, contact us to learn more.

Ammonia recovery and BOD treatment for small towns and municipalities

Total nitrogen and phosphorus recovery for medium-to-large cities

Nutrient recovery and surcharge prevention for industrial applications

Advantages of the RAB System

Lower Energy and Operational Costs

No Costly Carbon or Chemical Inputs

Simply Scrape Harvested Algae

Sellable Algae Offsets Operational Costs

Secondary Treatment with Nutrient Removal

The RAB system is well suited to be located after primary sedimentation when Biochemical Oxygen Demand (BOD), Ammonia (NH3), Total Nitrogen (TN), and/or Total Phosphorus (TP) Treatment are needed. When the BOD concentration is higher, the RAB system will grow a mixed culture of both bacteria and alga, which can simultaneously remove BOD, NH3, TN and TP.

Side-Stream Treatment

Side-Streams at wastewater treatment plants, such as anaerobic digestion effluent and sludge thickening supernatant typically are recirculated back to the front-end of the plant. These waste streams are typically very nutrient dense with relatively low flows (compared to the rest of the plant). Side streams have nutrient concentrations ideal for algae growth and our RAB system.

Tertiary Treatment

The RAB system can be a simple retrofit on the back-end of an existing wastewater treatment plant for polishing TN and TP to meet stricter effluent discharge limits. This allows plants to keep their existing infrastructure, preventing costly upgrades to the entire plant. The RAB is especially well-suited for fixed film plants.

Why Our Technology

Not only does Gross-Wen Technologies supply a superior water treatment solution in terms of environmental impact, but our process is also a less expensive one. We’re happy to provide municipalities and wastewater-producing industries an alternative to the bacterial and chemical treatment systems commonly on the market today.

Our process has also been approved by the Iowa regulatory agency, IDNR, as a safe and reliable treatment option for municipal and industrial wastewaters. We are currently also being evaluated by several other state agencies across the country and are fully prepared to engage your local authorities through the approval process.

We don’t just think green, we grow it.