Wastewater bioremediation coupled with energy production via photosynthetic microorganisms

TECHNOLOGY DESCRIPTION

IMDEA Energy, Spanish Research Institute, working on sustainable fuel production, has designed a system for a dual purpose: wastewater nutrients recovery and production of energy as biogas.
On one hand, nutrients required for microalgae cultivation have been identified as a major nonenergetic cost of the global process to produce microalgae biomass. Microalgae production as a by-product of wastewater treatment is a promising option to significantly improve economics and reduce the environmental footprint of the process, avoiding freshwater and fertilizers’ consumption. Therefore the ability of microalgae for nutrients uptake and hence nutrients recovery is foreseen as a potential strategy to decrease energetic costs involved in other conventional aerobic treatments such as activated sludge. Additionally, the conversion of inorganic wastewater nutrients into organic matter through photosynthesis results in a
microalgae biomass that can be used for energy purposes.
The institute has the facilities to scale up the best strategies elucidated in lab-scale. Best case scenarios can be implemented in two different photobioreactors configuration at pilot plant scale. The pilot plant consists of two types of photobioreactors, namely open (raceways) and closed to the atmosphere (bubbled-columns).
The pilot plant is highly versatile since the reactors may be operated independently or in sequential mode. The photobioreactors are fully equipped to monitor the microalgae cultivation online. This singular infrastructure has been designed in order to compare and optimize two of the most common algae cultivation systems. Performance, productivity and associated costs of different algae cultivation systems will be compared at pilot scale.
Once the biomass is concentrated, this organic substrate can be used for biogas production (heat and power generation). Biogas is a mixture of gases produced by the breakdown of organic matter in the absence of oxygen.
This integrated approach would have an immediate economic impact reducing operational costs and payback time of a hypothetical plant investment as well as contributing to the greenhouse gas emission reduction targets.

BENEFITS

The biotechnology laboratory is fully equipped to conduct chemical and biochemical
characterization of organic substrates and wastewater streams. The laboratory has also the knowledge to conduct and evaluate, biomethane production potential assays (batch and continuous) as well as photosynthetic growth of microorganisms in aquatic systems.
The working volume of the raceways is 0.3 m3 each. In the case of the closed photobioreactor, it consists of three modules of 4 columns each module. Each column has a working volume of 0.76 m3, thus each module presents the same volume as the raceway reactors.
This singular infrastructure has been designed in order to compare and optimize two of the most common algae cultivation systems. This facility is available to up-scale processes already proven successful at laboratory scale.

LIMITATIONS

No limitations taking into account the especifications of the installation.

APPLICATIONS

• Wastewater treatment plants
• Biogas production
• Biorefinery plants
The Institute is looking for service agreement with companies in the valorization of a wastewater stream or an organic residue suitable for biogas production who need technology development.
Also, they are looking for a research cooperation agreement with companies or institutes for projects on the field.

MATERIALS