Students in Cascade High School's Advanced Biology class will use a photosynthetic bioreactor coil to achieve the following goals:

The photosynthetic bioreactor, called a bio-coil, contains a chlorella algae culture maintained in suspension at a high concentration, causing the culture to become nutrient deficient. When the bio-coil intakes sewage wastewater, the nutrient-deprived chlorella culture absorbs and incorporates nitrates, phosphates and ammonia in large amounts. The algae pass through coils of clear, food-grade PVC tubing, wound horizontally around a vertical frame, to allow complete nutrient absorption. A pump that produces compressed air is incorporated into the tubing. The tubes provide a controlled environment, illuminated primarily by sunlight, where the algae undergo photosynthesis, sequestering CO2 from the air and producing oxygen. The algae then concentrate in a settling tank where it can be easily harvested or recycled. The biomass is removed in a liquid form and can be dried in an oven to be used as animal feed, fertilizer or fuel. The water, now clean, is discharged back into the environment.

In 1995, Cascade Reservoir was experiencing the effects of extreme cultural eutrophication. The algae mat was so thick and intense that the smell overwhelmed the entire community. A group of Cascade High School students accepted the challenge to improve the reservoir's water quality. They focused on an upstream community's practice of discharging secondary sewage effluent into the river that feeds the reservoir. This group of students, four girls who affectionately called themselves the "Sewage Sisters," discovered in a National Geographic magazine a cutting-edge technology from England that could help. After establishing a working relationship with the company that developed the bio-coil, the students raised $22,000 in grant funding to build a pilot model and test its efficiency. They designed a 10' high, 10' diameter bio-coil with manifolds, pumps, tubes and tanks to place at Cascade Sewage Lagoons. In 1998, students presented their findings at the National Science Teacher's Convention in Las Vegas and work continued on the bio-coil, with new students taking over the project year-by-year.

In 2005, the bio-coil students were contacted by Lloyd Godson, a scientist from Australia who was interested in the project, but not for wastewater treatment. Godson asked if the bio-coil design could be adapted to function as a life support apparatus in a self-sustained underwater habitat. Could the bio-coil scrub the CO2 waste from a humans' breathing and in return provide the human with the oxygen needed to survive? Students raised $30,000 in grants and donations to work with Godson in the creation of a new bio-coil to produce oxygen in his underwater BioSUB. In March 2006, six students traveled to Australia and spent three weeks building a bio-coil to be installed in the BioSUB. Godson spent twelve days underwater in his BioSUB with a portion of his oxygen provided by the bio-coil.

In 2008, students decided to expand the project even further and use the bio-coil to tackle several environmental issues at once. The bio-coil could be used to remove excess nutrients from waste streams to ensure good water quality and scrub CO2 from the atmosphere while producing more oxygen, as in the past. Furthermore, the algae by-product created during these processes could be used as bio-diesel in Cascade's school busses, providing an alternative energy solution to the growing costs and environmental impacts of oil.

Partner Statement

The Nature Conservancy is proud to partner with the Bio-coil project of the Advanced Biology Class of Cascade High School. We applaud your efforts to finding science based solutions to environmental problems and thinking of its impacts beyond the Cascade Reservoir. Your ability to think of applications related to air, water and alternative energy sources both locally and globally is commendable.