Prepared By:Rashmi Paliwal

IntroductionImmobilized MicroalgaeTransgenic AlgaeAdvantages of Algal TechnologyApplications

World is facing the problems with a wide variety of pollutants.

Many methods are available for the removal of these pollutants but they are not widely acceptable.

Biological methods are often preferred since they have many advantages like rapid biodegradation rates, low sludge yield and excellent process stability.

Use of macro-algae or micro-algae for the removal or biotransformation of pollutants, including nutrients and xenobiotics from wastewater and CO2 from waste air.

Naturally occurring phenomenon

Algae utilize the wastes as nutritional sources and enzymatically degrade the pollutants.

The xenobiotics and heavy metals are known to be detoxified/ transformed/or volatilized by algal metabolism.

An integrated algae and bacterial based wasted water system can remove a wide variety of contaminants.

Division

(Common Name)

Algal Species Metal

Chlorophyta

(Green algae)

Phaeophyta

(Brown algae)

Rhodophyta

(Red algae)

Chlorella sp. and Scenedesmus sp.

Cladophora, Thalassiosira pseudonana and Ditylum birghtwellii

Chlorella vulgaris

Scendesmus acutus

Scenedesmus obliquus

Scenedesmus subspicatus

Scenedesmus quadricauda

Sargasuum nutan

Ascophyllum nodosum,

S. Vulgare

Fucus Vesiculosus

Laminaria japonica

Acrosorium uncinatum

Cu, Cd

Cu, Zn and Cd

Zn, Cd

Cr

Co

Al

Zn, Cu and Ni

Au

Au, Cd, Co, Ni, Pb

Cu, Ni, Pb, Cd

Pb, Ni, Cu, Cd, Zn

Zn, Cu

Cu, Zn, Ni, Pb

Davis, et.al., (2003)

Immobilization:Transfer of cells from a free state to a state in which they are confined/localized in a certain defined region of space.

Advantages:Reusing the biomass after regeneration.Avoids filtration of the treated wastewater.More than one microorganism can be immobilize .

Microalgae species Immobilizing Material Pollutant

Chlorella homosphaera

C. vulgaris

Chlamydomonas reinhardtii

Oscillatoria sp.

Scenedesmus acutus

Scenedesmus quadricauda

Chlorella regularis

Spirulina platensis

Alginate

Alginate, k-Carrageenan

Polyurethane foam

Silica gel

Alginate

Alginate

Alginate, k-Carrageenan

Polyurethane foam

Alginate

Polyacrylamide

Silica gel

Cd, Au, Zn

Cd, Cu, Zn

Hg

Cd, Pb, Hg

Cd

Cd, Cr

Zn

Ni, Zn, Cu

Uranium

Cd

Microalgae species Immobilizing Material

Pollutant

Phormidium laminosum

Chlorella salina

Sargassum baccularia

Chlorella emersonii; C. vulgaris

Phaeodactylum tricornutum

Chlorella sp.; Phormidium sp.;

Scenedesmus obliquus;

Stichococcus sp.

Polysulphone foam

and epoxy resin

Alginate

Polyvinyl alcohol

Alginate

Alginate

Capron fibers

(synthetic)

Mixture of Cu, Fe, Ni, Zn

Mn, Zn, Co

Cu

Organotin Compounds

(Biocides)

linear alkylbenzene

sulphonate (LAS) a

surfactant

Mix of phenols, oil spill

and heavy metals

Contd…

Bashan & Bashan, (2010)

Transgenesis in algae is a complex but fast growing technique.

Genetic manipulations in algae to improve their detoxification ability.

Very few species of microalgae have been genetically transformed with efficiency.

Requirement of Algal Transformation:

Previous molecular, biochemical, physiological or ecological knowledge of the target species.

Extensive sequence information.

Species Utilization

Green algae

Chlamydomonas reinhardtii

Ulva spp.

Monostroma spp.

Brown algae

Laminaria spp.

Sargassum spp.

Macrocystis pyrifera

Lessonia spp.

biomass from transgenics for animal health and feed; bioremediation,

environmental monitoring; production of recombinant proteins.

biomass for food and feed; extracts for cosmetics, wastewater

Treatment.

biomass for food; wastewater treatment.

alginate for food, pharmaceuticals, and cosmetics; biomass for food

and feed; wastewater treatment.

Wastewater treatment.

alginate for pharmaceuticals, cosmetics, food, and textile printing;

biomass for feed and fuel; wastewater treatment.

alginate for pharmaceuticals, cosmetics, food, and textile printing;

wastewater treatment.

Hallmann, (2007)

Cost parameter Conventional Effluent Treatment

Phycoremediation Annual cost benefit

Acidity -High levels of dissolved carbon dioxide

caustic soda Algal treatment Rs. 50 lakhs spent for caustic soda annually is saved (100%).

Sludge formation About 290 tonnes of sludge produced annually from this treatment.

There is no residual  sludge.

The sludge disposal cost Rs. 3 lakhs annually. This cost is saved.

Structures and space.

11,000 Sq Mtrs of  masonry tank for evaporating the effluent

3000 sq mtrs of tank for containing and evaporating the effluent.

About 75% of the effluent treatment facility space is released.

http://phycospectrum.com/moresnap.html

Phycoremediation is a multi-faceted effluent treatment process. As a green cell factory algae can

tackle simultaneously more than one problem. However, the development of more efficient

pollutants removal algal systems requires further research in key areas.

Bashan, L.E. and Bashan, Y., (2010). Immobilized Microalgae for Removing Pollutants: Review of Practical Aspects. Bioresource Technology. 101: 1611–1627

Davis, T.A., Volesky, B., and Mucci, A., (2003). A review of the biochemistry of heavy metal biosorption by brown algae. Water Research., 37: 4311–4330

Hallmann A. (2007) Algal Transgenics and Biotechnology. Transgenic Plant Journal. 1: 81-98

Kobayashi, H. and Rittman, B.E. (1982). Microbial removal of hazardous organic compounds. Environ. Sci. Technol., 16: 70-183

Torres, M.A., Barros M.P., Campos, S.C.G., Pinto, E., Rajamani, S., Sayre, R.T. and Colepicolo, P. (2008). Biochemical Biomarker in Algae and Marine Pollution: A review. Ecotoxicology and Environmental Safety. 71: 1-15

http://phycospectrum.com/moresnap.html www.oldcastleprecast.com http://www.nasa.gov/centers/ames/greenspace/ www.google.com