Low Cost, Low Energy, Method of Dewatering Cultures of the Green Microalgae Nannochloris oculata: Electrocoagulation
Abstract
Microalgae have received a substantial amount of attention as an alternative fuel
feedstock due to their ability to produce large quantities of lipids. The goal of this
research was to determine the ideal operating parameters for electrocoagulation; a low
cost, low energy method of dewatering cultures of microalgae. The objectives of this
research focus on recognizing parameters that influence the overall efficiency of the
process, effective electrode materials, and finally directional improvements in operating
parameters contributing to a high reduction in optical density. Variables found to have a
statistically significant effect on the efficiency of electrocoagulation were the electrode
material, current, and duration. With no adjustment of the algae culture prior to
electrocoagulation, iron and nickel were identified as the best performing electrode
materials, in terms of optical density reduction. Of the materials tested, iron was found to
achieve the greatest recovery of microalgae at the lowest power consumption, while
staying below the threshold for animal feed tolerance. The most desirable operating
parameters for electrocoagulation, within the confines of the experimental apparatus and
using iron electrodes, were found to be a current of 0.3 amps and a 15 min reaction time.
Increases in current and duration were found to provide the highest levels of optical
density reduction. However, the average voltage, and therefore, power consumption are
the highest when current and duration are maximized. Additional testing should be
performed at higher currents and longer durations, in an attempt to find a peak in the
optical density reduction.
Citation
Murdock, Jared (2014). Low Cost, Low Energy, Method of Dewatering Cultures of the Green Microalgae Nannochloris oculata: Electrocoagulation. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /152735.