High algal production rates achieved in a shallow outdoor flume

Abstract

A mass culture of Tetraselmis suecica grown in seawater enriched with only inorganic nutrients and CO(2) in a shallow outdoor flume containing foil arrays to effect systematic vertical mixing achieved average daily production rates of over 40 g ash-free dry wt (AFDW)/m(2) over periods as long as one month when grown on a three-day dilution cycle. Photosynthetic efficiencies associated with these high production rates averaged 8-11% based on visible irradiance. Operation of the system in a one-, two-, or four-day dilution cycle resulted in lower photosynthetic efficiencies of 6-7%. A remarkable feature of the three-day dilution cycle results was the fact that production on the third day after dilution averaged 60-70 g AFDW/m(2), and corresponding photosynthetic efficiencies averaged 13-19%. The high production rates and photosynthetic efficiencies achieved on the third day after dilution may have reflected the nonequilibrium nature of the production cycle and, in particular, the fact that the adaptation of the cells to changing light condition lagged behind light condition in the culture.

Systems and economic analysis of microalgae ponds for conversion of CO{sub 2} to biomass. Quarterly technical progress report, September 1993--December 1993

“…The study included a comparison of paddle wheels with Archimedes screws and propellers; they were all similar in power inputs. Foils placed into the pond to stimulate turbulence increased productivities (see also Laws et al, 1983Laws et al, ,1986Laws et al, ,1988. Productivities were generally lower than in prior studies by this group, about 20 g biomass ash free dry weight/m2/day, possibly due to high respiratory losses.…”

“…This program, supported many basic research projects, including isolation of a large number of algal strains and investigation of biochemical and genetic aspects of lipid production in microalgae (SERI 1983(SERI ,1984(SERI , 1987a(SERI ,b, 1989NREL 1992). Three outdoor algal production facilities were supported by the ASP, in Hawaii (Laws et al, 1983(Laws et al, ,1986(Laws et al, ,1988, California (Benemann et al, 1981(Benemann et al, ,1983 and New Mexico, where two 0.1 hectare ponds (one lined and one unlined) were operated for two years Tillett, 1989, 1992).…”

Comparison of Marine Microalgae Culture Systems for Fuels Production and Carbon Sequestration

“…A great deal of literature over the years has suggested that longer periodicities can increase photosynthetic conversion efficiencies (e.g. Laws et al, 1986, Laws andBerning, 1991). Thus, further investigation of this phenomenon was warranted.…”

“…Such light modulation is only an experimental tool, it cannot be applied in practice to large-scale mass cultures. Previous studies of light modulation in algal ponds, so-called "organized mixing" (Laws et al, 1986), did demonstrate interesting productivity enhancement effects, but also cannot be economically scaled-up.…”

Biotechnology of algal biomass production: a review of systems for outdoor mass culture

“…The culture is forced to run through the slit, creating a turbulent flow. Laws et al (1986) described a mixing system consisting of a continuous flume containing arrays of foils similar in design to segments of airplane wings. They achieved average daily biomass production rates over 40 g d wt m-2 over periods as long as one month.…”