A cyclic photobioreactor (PBR) for biofilm control in algae cultures - 2053
- *Abstract
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Overview
Algae cultures are maintained at commercial scale for a variety of reasons, such as the production of nutrient supplements, biofuel feedstocks, and bioplastic production. The use of open ponds to grow algae culture has several shortcomings. Open ponds provide no means of preventing invasive species from being introduced, and hence poly-cultures coexist limiting quality control. Open ponds also require significant water make-up due to evaporative losses, thus making control of soluble nutrient balances complicated. Additionally, since algae require sunlight to grow, dense algae cultures limit sunlight penetration in open ponds to a depth of approximately 5 inches; thus, achieving high productivity requires open ponds to be shallow with a large areal footprint.
To maximize productivity while ensuring quality control of the algae culture being grown, closed systems such as photobioreactors (PBRs) offer specific advantages over conventional open pond technologies. UK researchers are developing a closed system that allows for production of algae that minimizes biofilm accumulation and energy consumption while providing homogenous harvested cultures.
Invention
Photobioreactor (PBR) systems provide a contained growth environment for algae cultures, thus minimizing contamination from invasive species while eliminating evaporative losses. UK researchers are developing a PBR system comprised of clear vertical tubes (to maximize sunlight exposure) arranged in offset parallel rows (to minimize shading), thereby encouraging maximal culture growth. A pump fills the the vertical tubes with the algae culture by means of a pump, and the pump operates only long enough to fill the vertical tubes, thus reducing energy requirements. Since the culture volume resides in the vertical tubes, multiple parallel rows can be filled using a much smaller feed tank with a single small pump using a system of automated control valves.
To ensure culture homogeneity while maximizing culture exposure to sunlight, each parallel row is periodically (i.e., every 2-6 hours) recycled back to the feed tank where it is thoroughly mixed before being reintroduced back into the vertical tubes. This cyclic filling and draining operation provides the opportunity to remedy a serious problematic limitation of PBRs, namely controlling biofilm formation.
Applications
- biofuels
- nutrient supplements
- bioplastics
Advantages
- higher algae growth rates
- controlled biofilm formation
- cyclic pumping reduces energy requirements
- minimized feed tank size requirements
IP Status: U.S. Patent Application No. 15/621,776
- Country/Region
- USA
