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Title: Species control in large-scale algal biomass production. Final report

Technical Report ·
DOI:https://doi.org/10.2172/6672614· OSTI ID:6672614

This project deals with the development of biomass production technology for planktonic microalgae. A review of this subject details the use of such algae in waste treatment and the problem of harvesting the many types of microscopic algae occurring in ponds. The solution of this problem is deemed to be development of algal species control techniques which allow cultivation of desirable algal types harvestable through the most economic methods available. In the outdoor experiments, circular 3-m/sup 2/ ponds were used and were fed daily settled sewage, were mixed with paddle wheels, and were maintained at a variable detention time and fixed depth (10 inches). The ponds were inoculated with the filamentous blue-green alga, Oscillatoria and harvested with microstrainers. The Oscillatoria culture could not be maintained for long against an invading Scenedesmus sp. The naturally appearing alga Micractinium was much more successful in maintaining itself in the experimental ponds. However, even this species could not survive adverse conditions despite extensive recycling. The outdoor experimental ponds were effective in removing chemical oxygen demand (COD) and ammonia-nitrogen (NH/sub 3/-N) from influent sewage, achieving removals of 50 percent and 80 percent, respectively. Laboratory experiments concentrated on demonstrating the selective recycle theory. A mixture of Spirulina (a filamentous blue-green alga) and a small unicellular green alga could be maintained with either organism predominating, depending on recycling. An economic analysis of algal biomass production indicates the feasibility of algal biomass production and conversion to methane and fertilizer as by-products of sewage or liquid waste treatment assuming the availability of species control technology.

Research Organization:
California Univ., Berkeley (USA). Sanitary Engineering Research Lab.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6672614
Report Number(s):
SAN-7405-77/1; UCB/SERL-77-5
Country of Publication:
United States
Language:
English