20.20(S10):Notebook/BEI/2010/04/14

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Biological Engineering Project Specification

  1. We want to develop a system that can produce oil for small scale consumers rather than industrial conglomerates.

Examples may include small rural communities or individual families. Based on this scale,

  • Nitrogen and Phosphorus Reclamation from Municipal Wastewater through an Artificial Food-Chain System

Unfortunately, Daphnia, like all heterotrophic consumers, collect and ingest much more material than they can incorporate in new tissue. Nitrogen and phosphorus, among other elements, are continuously released both as solutes (mainly as Daphnia magna ammonia and orthophosphate) or in particulate form (faeces).


"the extraordinary properties of the Botryococcus braunii algae: give the microscopic green strands enough light – and plenty of carbon dioxide – and they excrete oil. The tiny globules of oil that form on the surface of the algae can be easily harvested and then refined using the same “cracking” technologies with which the oil industry now converts crude into everything from jet fuel to plastics. " "A prospective algae-breeding oil concern would either have to invest billions of dollars in expensive breeder tanks – at a cost of around three times what the oil would sell for on the international market over the lifetime of the tanks – or find an enormous expanse of well-irrigated land in a country where labour can be bought very cheaply. It is for this reason that Professor Watanabe believes the world’s first algae farms will be constructed in countries such as Indonesia or Vietnam."

But, a shortcoming of B. braunii is its relatively slow growth rate. While the algae that produce 'vegetable-type' oils may double their growth every six to 12 hours, B. braunii’s doubling rate is about four days, he said.

" Continuous culture of hydrocarbon-rich microalga Botryococcus braunii in secondarily treated sewage "

The hydrocarbon-rich green microalga, Botryococcus braunii, was grown on secondarily treated sewage (STS) in a continuous bioreactor system. The algal biomass increased at a sustained rate of 196 mg dry weight/l per week for 1 month. The hydrocarbon content of algae grown on STS (49%) compared well with that of algae grown on an artificial medium. The concentrations of nitrate and phosphate ions in STS decreased from 5.5 to 4.0 mg nitrogen/l and 0.08 to 0.03 mg phosphorus/l, respectively, by algal consumption. STS would thus appear to suffice as an appropriate medium for continuously sustainable growth of B. braunii and the algal consumption of nitrate and phosphate should help in removing these ions from STS.

Toread:

"When operated at 120-h detention time of raw wastewater, the high-rate oxidation pond maintained a steady state with respect to algal growth and oxygen concentration, and the concentration of ammonia did not exceed 1.0 mM." (Source Below)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC169837/

However, their chemical structure is not affected. Intricate relationships were observed in B. braunii-bacteria systems and numerous factors (including, in some cultures, large positive effects due to bacterially produced CO2) were implicated.


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