Harvesting of microalgae by bio-flocculation

The high-energy input for harvesting biomass makes current commercial microalgal biodiesel production economically unfeasible. A novel harvesting method is presented as a cost and energy efficient alternative: the bio-flocculation by using one flocculating microalga to concentrate the non-flocculating microalga of interest. Three flocculating microalgae, tested for harvesting of microalgae from different habitats, improved the sedimentation rate of the accompanying microalga and increased the recovery of biomass. The advantages of this method are that no addition of chemical flocculants is required and that similar cultivation conditions can be used for the flocculating microalgae as for the microalgae of interest that accumulate lipids. This method is as easy and effective as chemical flocculation which is applied at industrial scale, however in contrast it is sustainable and cost-effective as no costs are involved for pre-treatment of the biomass for oil extraction and for pre-treatment of the medium before it can be re-used

Long term outdoor operation of a tubular airlift pilot photobioreactor and a high rate algal pond as tertiary treatment of urban wastewater.

530 L high rate alga pond (HRAP) and 380 L airlift tubular photobioreactor (TPBR) were operated and compared in a urban wastewater treatment plant (WWTP), with the main purpose of removing nitrogen and phosphorous from the effluent of the WWTP while generating a valuable biomass. The photosynthetic activity in TPBR was during entire experiment higher than HRAP. The maximum areal productivity reached was 8.26 ± 1.43 and 21.76 ± 0.3 g SS m−2 d−1 for HRAP and TPBR respectively. Total nitrogen (TN) removal averaged 89.68 ± 3.12 and 65.12 ± 2.87% for TPBR and HRAP respectively, while for total phosphorus (TP) TPBR and HRAP averaged 86.71 ± 0.61 and 58.78 ± 1.17% respectively. The lipid content showed no significant differences (p < 0.05) between HRAP and TPBR averaging 20.80 ± 0.22 wt%. The main operating disadvantage of TPBR versus HRAP was the sever biofouling which forced to stop the experiment. Under the same conditions of operation TPBR was more limited at low temperatures than HRAP, and HRAP was more light limited than TPBR

Large irritation fibroma of hard palate: A case report of a rare clinical entity

Fibromas are benign tumors of connective tissue common in the oral cavity but rare on hard palate. This paper reports on an asymptomatic, slowly growing mass on the hard palate of a 90-year-old lady, with a reported use of denture for two decades. The patient presented with a 2.2cm, smooth-surfaced, well-circumscribed nodule attached with a stalk to the palatal mucosa. After excision, the histopathological examination revealed a mass of fibrous connective tissue, covered by stratified squamous epithelium with focal low-medium grade hyperplasia and hyperkeratosis. These findings were consistent with irritation fibroma of hard palate, a rare entity, which should be considered as a possible diagnosis for tumors of the area by every physician. © Alexios Tsikopoulos et al

Harvesting, thickening and dewartering microalgae biomass

The recovery and processing of microalgae biomass from a culture media is an essential component for the production of almost all microalgae products. Microalgae recovery techniques can be used individually (single-stage) or in combination (multi-stage) and the choice is often dependent on the species of microalgae, desired product concentration and product quality. A wide range of solid-liquid separation techniques is available and this chapter compares the technologies and assess the technical and economic considerations for each option. The major challenge in selecting an appropriate technology for biofuels production from microalgae is that traditional microalgae concentration processes have generally used energy-intensive unit operations that are expensive.Stephen L. Pahl, Andrew K. Lee, Theo Kalaitzidis, Peter J. Ashman, Suraj Sathe, and David M. Lewi