Algal Flocculation with Synthetic Organic Polyelectrolytes

Tenney, Mark W.; Echelberger, Wayne F.; Schuessler, Ronald G.; Pavoni, Joseph L.

doi:10.1128/aem.18.6.965-971.1969

Cited by 92 publications

(36 citation statements)

References 1 publication

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“…Knuckey et al [25] reported that the non-ionic polymer Magnafloc LT25 settled a wide range of microalgae species effectively using a rate of 0.5 mg/L in a pH adjusted media to 10-10.6. Tenney et al [172] noted the most effective flocculation resulted when using cationic polyelectrolytes at low pH levels. Ras et al [47] noted that the Chlorella species flocculated when the pH was increased to 11-12.…”

Section: Organic Flocculationmentioning

confidence: 99%

“…The polyelectrolyte charge plays an important role in the flocculation process of microalgae. Anionic polyelectrolytes are not effective flocculent agents on their own due to the negatively charged microalgae cell surface because like charges repel one another and/or the length of the polymer is not sufficient enough to bridge the particles together [142,172]. It is for this reason that cationic polyelectrolytes are found to be much more effective in the flocculation of microalgae.…”

Section: Charge On Polymermentioning

confidence: 99%

“…Granados et al [30] showed that the species Chlorella and Scenedesmus were effectively flocculated to a concentration of 2 g/L after 15 min using polyelectrolyte dosages of 2-25 mg/g. Tenney et al [172] stated that the cationic polyelectrolyte polyamine was effective in flocculating the microalgae cells at a dosage of 2.5 mg/l. Sukenik et al [146] reported that marine microalgae Isochrysis galbana and Chlorella stigmatophora require 5-10 times more flocculent dosages than those required by freshwater microalgae.…”

Section: Flocculent Concentrationmentioning

confidence: 99%

See 2 more Smart Citations

Microalgae Harvesting Methods for Industrial Production of Biodiesel: Critical Review and Comparative Analysis

hattab¹,

Ghaly²,

Hammoud³

2015

J Fundam Renewable Energy Appl

119

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Microalgae biomass can be used to produce numerous value added products such as biodiesel, bioethanol, biogas and bio hydrogen, fish feed, animal feed, human food supplements and skin care products. Production of value added products from microalgae biomass requires growing and recovery of the algae biomass and extraction and downstream processing of the desired product. However, the major obstacle for using microalgae biomass on an industrial-scale for the production of biodiesel and other value added products is the dewatering step which accounts for 20-30% of the total costs associated with microalgae production and processing. The aim of this study was to review the current methods used for harvesting and concentrating microalgae and to perform a comparative analysis in order to determine the most efficient and economically viable dewatering methods for large scale processing of microalgae biomass. The harvesting techniques investigated included sedimentation, vacuum filtration, pressure filtration, cross flow filtration, disc stack centrifugation, decanter centrifuge, dispersed air floatation, dissolved air flotation, fluidic oscillation, inorganic flocculation, organic flocculation, auto-flocculation, bio-flocculation electrolytic coagulation, electrolytic flocculation and electrolytic floatation. Eight criteria were used for evaluation of these microalgae harvesting techniques: (a) dewatering efficiency (b) cost (c) toxicity (d) suitability for industrial scale (e) time (f) species specificity (g) reusability of media and (h) maintenance. Each criterion was assigned a score between 7 and 15 based on its degree of importance. Higher values were given to the criteria that were deemed most important for development of an efficient and economic large scale dewatering method for microalgae whereas lower values were given to criteria that were deemed necessary for determining a suitable method but were considered less important. The results indicated that of the 16 methods evaluated, 4 scored values of 80/100 and above and were deemed suitable for harvesting microalgae on an industrial scale. Three were physical techniques (disc stack centrifuge (87/100), cross flow filtration (84/100), decanter centrifugation (82/100)) and the forth was the organic flocculation (80) method. These techniques were deemed suitable for large scale use because of their effectiveness, low operational costs, suitability for numerous species, rapidness, minimal maintenance requirement and being environmentally friendly. The other methods were deemed unsuitable because they are not effective in dewatering a wide array of microalgae species, not suited for large volumes, costly and require high maintenance. Although each of the optimum techniques was deemed suitable for harvesting of microalgae on its merit, a combination of methods can also be used to enhance the recovery efficiency and improve the economics. The use of organic flocculation as an initial harvesting step to concentrate the algae suspension and the centrifugation (or filt...

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Section: Organic Flocculationmentioning

confidence: 99%

Section: Charge On Polymermentioning

confidence: 99%

Section: Flocculent Concentrationmentioning

confidence: 99%

See 1 more Smart Citation

Microalgae Harvesting Methods for Industrial Production of Biodiesel: Critical Review and Comparative Analysis

hattab¹,

Ghaly²,

Hammoud³

2015

J Fundam Renewable Energy Appl

119

View full text Add to dashboard Cite

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“…Another promising approach is to select for algae with the best settling properties by recycling settled algal cells to the treatment ponds the microalgae were initially harvested from [16,23], and [24]. Salim et al [24] observed that three microalgae (Scenedesmus obliquus, Tetraselmis suecica, and Ankistrodesms falcatus) appeared to improve recovery efficiency (settling) of two difficult-to-settle cultures of microalgae (C. vulgaris and Neochloris oleoabundans).…”

Section: Introductionmentioning

confidence: 99%

Settling and bioflocculation of two species of algae used in wastewater treatment and algae biomass production

Manheim

Nelson

2013

Env Prog and Sustain Energy

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The settling and bioflocculation of two strains of algae were investigated in the laboratory to provide insights to help improve algae settling in large-scale, algae-based wastewater treatment systems with simultaneous algae biofuel production. Energy-efficient algae harvesting methods are needed for cost-competitive production of biofuels from algae. The use of bacterially derived exudates (bioflocculation) is promising, but its use in high-rate algae pond (HRAP) wastewater systems has not yielded consistently reliable settling. The settling of the algae species Scenedesmus sp. and Chlorella vulgaris was investigated in the laboratory with and without cultures of the bacterium Burkholderia cepacia to investigate environmental effects on the settling of pure algal cultures and to examine possible bioflocculation by bacteria and bacterial exudates. Scenedesmus sp. and C. vulgaris responded in opposite ways to changes in operating conditions such as culture age and bioflocculation. Scenedesmus sp. settled better in later stationary growth stages, while C. vulgaris settled better in its early exponential growth phase. Scenedesmus sp. settling was improved by bioflocculation during early exponential and late stationary growth stages, but not during early stationary growth. Scenedesmus sp. responded better to B. cepacia cells plus filtrate (filtered bacterial broth) than to filtrate addition alone. In contrast, C. vulgaris settling was not improved via bioflocculation with neither the addition of B. cepacia cells nor filtrate at any growth stage. Longer contact time between the algae cells and bioflocculants improved the settling of Scenedesmus sp., but not the settling of C. vulgaris. Observed differences in settling and bioflocculation of the two algae species were attributed to differences in algal cell size and shape, culture density, and exudate type (i.e., capsular versus dissolved EPS). The widely different settling behavior of the two species of algae used in this research may explain the often varied results observed with mixed cultures in algae wastewater ponds. V C 2013 American Institute of Chemical Engineers Environ Prog, 32: 946-954, 2013

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“…polyacrylamide, alginate, starches) to aggregate algae, and spreading of minerals (e.g. yellow loess, montmorillonite, kaolinite) for clay-based flocculation (Tenney et al, 1969;Sridhar et al, 1988;Sengco and Anderson, 2004). However, these methods are limited by low efficiencies and also have the capacity to disrupt marine ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Construction of target‐specific virus‐like particles for the delivery of algicidal compounds to harmful algae

Kang

Eom

Kim

et al. 2014

Environmental Microbiology

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Harmful algal blooms (HABs) can lead to substantial socio-economic losses and extensive damage to aquatic ecosystems, drinking water sources and human health. Common algicidal techniques, including ozonation, ultrasonic treatment and dispersion of algae-killing chemicals, are unsatisfactory both economically and ecologically. This study therefore presents a novel alternative strategy for the efficient control of deleterious algae via the use of host-specific virus-like particles (VLPs) combined with chemically synthesized algicidal compounds. The capsid protein of HcRNAV34, a single-stranded RNA virus that infects the toxic dinoflagellate, Heterocapsa circularisquama, was expressed in and purified from Escherichia coli and then self-assembled into VLPs in vitro. Next, the algicidal compound, thiazolidinedione 49 (TD49), was encapsidated into HcRNAV34 VLPs for specific delivery to H. circularisquama. Consequently, HcRNAV34 VLPs demonstrated the same host selectivity as naturally occurring HcRNAV34 virions, while TD49-encapsidated VLPs showed a more potent target-specific algicidal effect than TD49 alone. These results indicate that target-specific VLPs for the delivery of cytotoxic compounds to nuisance algae might provide a safe, environmentally friendly approach for the management of HABs in aquatic ecosystems.

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Algal Flocculation with Synthetic Organic Polyelectrolytes

Cited by 92 publications

References 1 publication

Microalgae Harvesting Methods for Industrial Production of Biodiesel: Critical Review and Comparative Analysis

Microalgae Harvesting Methods for Industrial Production of Biodiesel: Critical Review and Comparative Analysis

Settling and bioflocculation of two species of algae used in wastewater treatment and algae biomass production

Construction of target‐specific virus‐like particles for the delivery of algicidal compounds to harmful algae

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