Test Program Goals over Four (4) Phases:
- Algal Production Rates
- CO2 absorption
- Energy Use
- Algae Production Cost
Phase 1 Results – Natural Gas Boiler
- 2 months of operation with no culture issues.
- Algae density of 1.7 g/l.
- No water added during two months of testing.
Phase 2 Results – Coal Boiler
- The waste water from harvesting can be re-used in the process to reduce water consumption and nutrient addition.
- Water consumption is about 1%/day.
- Developed biofilm cleaning process
- Based on testing of the algae, biomass from both natural gas and coal fueled boilers are acceptable for up to 10% by volume addition to cattle feed. The algae are high in protein and beneficial amino acids.
Phase 3 Results – Natural Gas Boiler
- Implemented an improved bio-film cleaning process.
- Harvest Trials
– 20% sustainable harvest concentration ~ 0.83 g/L @ 0.167 g/L/day
– 30% sustainable harvest concentration ~ 0.62 g/L @ 0.187 g/L/day
Phase 4 Tests – Natural Gas Boiler
- Higher light intensity increases algae growth rates.
- Stable and sustainable algae production was demonstrated with the Algae Photo Bio-reactor (APB).
- The algae consume phosphates and nitrates continuously, though at different rates. The process is limited by the phosphate consumption for waste water treatment processes.
- The LED’s are a large energy consumption point for the system versus the value of the energy in the algae.
- CO2 sequestration rates are tied to the algae production rate and volume of the reactor.
- The algae production costs were very high and due to scale and high energy use and costs. Labor costs were also a significant factor.
- Pilot plant designs suggest algae production can be scalable, reliable, and yield algae product for sale at or below $20/kg.
- Achieved 3.75 g/l density in reactors and growth rates up to 0.48 g/l/day.