green algae project

8/10/2019 Green Algae Project

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GREEN ALGAE

PROJECTCAN THEY SAVE THE WORLD....?

CONTENTS

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Green

Algae................................................

Micro and Macro

Algae..............................

Green algae used for carbon

sequestration and bio fuel

production.............................

Algae

fuel....................................................

Oil

Extraction...............................................

Su!aina"le #o!$!rea!%en! of%unici#al &a!e&a!er &i!'algae...............................

Cul!i(a!ion of MicroAlgae.........................

A feai"ili!) !ud) on !'e #roduc!ionof

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%icroalgae..................................................

! GREEN ALGAE PROJECT

GREEN ALGAE

"The classic "green algae" are mostlymicroscopic freshwater forms and large seaweed.Some species may be as large as 25 cm in width,

and attain a length of 8 meters like the sea lettuceshown here. The green algae, and all other plantgroups, contain firm cell walls often composed ofcomplex compounds such as cellulose. nergyfrom the sun in the form of light is captured bythe green algae, green plants and some bacteriathrough photosynthesis. This process is the route

by which !irtually all energy enters ourbiosphere."


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KNOWN SPECIES

At least 7,000

SIZE RANGE

Less than 25 micro meters to 8 meters

WHERE THEY LIVE

Mostly in fresh waters and marine environments; also in hot springs, on the surface of snow and treetruns, and in soil

ECOLOGICAL ROLES AND HUMAN USES

At the !ase of the food chain; "elp to purify sewage, #tore car!on, "umans use green algae as food,as feed for animals, and in !iological research

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Micro and Macro Alga!

Two kinds of algae exist macroalgae, also known as seaweed and microalgae. #icroalgae are!ery small plant$like organisms %&'$ ( to 5) *m+, which can be seen with the aid of amicroscope. nlike higher plants, microalgae do not ha!e roots, stems and lea!es.#icroalgae, capable to performphotosynthesis, are important for life on earth- they produceapproximately half of the atmospheric oxygen and use simultaneously the greenhouse gascarbon dioxide to grow photoautotrophically.n addition, life in oceans, seas and lakes is dependent on microalgae, because these are at the

bottom end of the food chain.

#acroalgae are seaweed or kelp $ a/uatic 0plants1 that are culti!ated either directly in thesea, attached to solid structures like poles and rafts, or, in some cases, as small indi!idual

plants, kept in suspension in agitated ponds. #acroalgae are produced for their content ofgelling substances agar, alginates and carrageenans and for food the annual global

production of seaweed is se!eral million tons. 3ompared to other types of a/uaculture, theproduction of seaweed is only surpassed by freshwater fishes. 4resently there is also interestin seaweeds as a feedstock for production of biofuels.n general, microalgae are cultured inphotobioreactorswhile macroalgae are cultured innatural en!ironments. hen we refer to algae on this website, we refer to microalgae.

The biodi!ersity of microalgae is enormous and they represent an almost untapped resource.t has been estimated that about 2)),)))$8)),)))species exist of which about 65,))) speciesare described. 7!er (5,))) no!el compounds originating from algal biomass ha!e beenchemically determined %3ardooet al.2))9+. #ost of these microalgae species produceuni/ue products like carotenoids, antioxidants, fatty acids, enymes, polymers, peptides,toxins and sterols.The chemical composition of microalgae is not an intrinsic constant factor but !aries o!er awide range, both depending on speciesand on culti!ation conditions. t is possible toaccumulate the desired products in microalgae to a large extend by changing en!ironmentalfactors like temperature, illumination, p:, 372supply, salt and nutrients.

3ollected ;rom

# GREEN ALGAE PROJECT
http://www.algae.wur.nl/UK/factsonalgae/photosynthesis/http://www.algae.wur.nl/UK/technologies/production/http://www.algae.wur.nl/UK/factsonalgae/species/http://www.algae.wur.nl/UK/applications/http://www.algae.wur.nl/UK/factsonalgae/species/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/temperature/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/light/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/nutrients/http://www.algae.wur.nl/UK/factsonalgae/photosynthesis/http://www.algae.wur.nl/UK/technologies/production/http://www.algae.wur.nl/UK/factsonalgae/species/http://www.algae.wur.nl/UK/applications/http://www.algae.wur.nl/UK/factsonalgae/species/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/temperature/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/light/http://www.algae.wur.nl/UK/factsonalgae/growing_algae/nutrients/


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Energy - Green algae used for

carbon sequestration and bio

fuel production

saac percent of the nitrousoxide as well, resulting in a much cleaner exhaust.

The algae is har!ested daily and its oil extracted to make biodiesel for transportuse, lea!ing a green dry flake that can be further processed to ethanol, also atransport fuel .

?reen;uel, the company set up by ) gallons from soybean.


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?reenfuel is not alone in racing to make oil out of algae. ?reenshift3orporation, an incubator company based in #ount Crlington Dew Eersey,licensed a 372$scrubbing screen$like filter de!eloped by Fa!id on creating renewable transportation fuel with algae makinguse of waste 372from

3oal fired power plants. The proAect, led by DGH scientist Eohn Sheehan, was

funded at I25.)5 m o!er the 2)$year period, compared to the total spendingunder the


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Algae fuelAlgae fuel, also called algal fuel, algaeoleumor second-generation bio fuel, is a bio fuelwhich is deri!ed from algae. Furing photosynthesis, algae and other photosyntheticorganisms capture carbon dioxide and sunlight and con!ert it into oxygen and biomass. p toBBK of the carbon dioxide in solution can be con!erted, which was shown by eissman andTillett %(BB2+ in large$scale open$pond systems. Cs of 2))8, such fuels remain too expensi!eto replace other commercially a!ailable fuels, with the cost of !arious algae species typically

between SI5() per kilogram.


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organism can use sunlight to produce lipids, or oil. The nited States Fepartment of nergyestimates that if algae fuel replaced all the petroleum fuel in the nited States, it would

re/uire (5,))) s/uare miles %=),))) km2+. This is less than (M9the area of corn har!ested in thenited States in 2))).

Different fuels produced from algae:

Biodiesel

3urrently most research into efficient algal$oil production is being done in the pri!ate sector,but predictions from small scale production experiments bear out that using algae to producebiodiesel may be the only !iable method by which to produce enough automoti!e fuel toreplace current world diesel usage.

#icroalgae ha!e much faster growth rates than terrestrial crops. The per unit area yield of oilfrom algae is estimated to be from between 5,))) to 2),))) S gallons per acre per year%=,9)) to (8,))) m6'km2Na+ this is 9 to 6) times greater than the next best crop, 3hinesetallow %9)) S gal'acreNa or >5) m6'km2Na+

Studies show that algae can produce up to >)K of their biomass in the form of oil.


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Through the use of algaculture grown organisms and cultures, !arious polymeric materialscan be broken down into methane.O(5P

S!

The algal$oil feedstock that is used to produce biodiesel can also be used for fuel directly as"Straight Qegetable 7il", %SQ7+. The benefit of using the oil in this manner is that it doesnLtre/uire the additional energy needed for transesterification, %processing the oil with analcohol and a catalyst to produce biodiesel+. The drawback is that it does re/uiremodifications to a normal diesel engine. Transesterified biodiesel can be run in an unmodifiedmodern diesel engine, pro!ided the engine is designed to use ultra$low sulfur diesel, which,as of 2))>, is the new diesel fuel standard in the nited States.

;rom ikipedia

Oil ExtractionClgae oils ha!e a !ariety of commercial and industrial uses, and are extracted through a wide!ariety of methods. stimates of the cost to extract oil from microalgae !ary, but are likely to

be around I(.8) %SI+'kg %compared to I).5) %SI+'kg for palm oil+.

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http://en.wikipedia.org/wiki/Transesterificationhttp://en.wikipedia.org/wiki/Transesterification


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Physical extraction

n the first step of extraction, the oil must be separated from the rest of the algae. Thesimplest method is mechanical crushing. hen algae are dried it retains its oil content, whichthen can be "pressed" out with an oil press. #any commercial manufacturers of !egetable oiluse a combination of mechanical pressing and chemical sol!ents in extracting oil. Sincedifferent strains of algae !ary widely in their physical attributes, !arious press configurations%screw, expeller, piston, etc.+ work better for specific algae types. 7ften, mechanical crushingis used in conAunction with chemical sol!ents, as described below.

7smotic shock is a sudden reduction in osmotic pressure, this can cause cells in a solution torupture. 7smotic shock is sometimes used to release cellular components, such as oil.

ltrasonic extraction, a branch of sonochemistry, can greatly accelerate extraction processes.sing an ultrasonic reactor, ultrasonic wa!es are used to create ca!itation bubbles in a sol!ent

material. hen these bubbles collapse near the cell walls, the resulting shock wa!es andli/uid Aets cause those cells walls to break and release their contents into asol!ent.ltrasonication can enhance basic enymatic extraction. The combination"sonoenymatic treatment" accelerates extraction and increases yields.

Chemical extraction

3hemical sol!ents are often used in the extraction of the oils. The downsides to usingsol!ents for oil extraction are the dangers in!ol!ed in working with the chemicals. 3are must

be taken to a!oid exposure to !apours and skin contact, either of which can cause serioushealth damage. 3hemical sol!ents also present an explosion haard.

C common choice of chemical sol!ent is hexane, which is widely used in the food industryand is relati!ely inexpensi!e.


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;G7# R4FC

Sustainable post-treatment ofmunicipal wastewater withalgae

Moti"ation

Cs part of the uropean ater ;ramework Firecti!e the effluent demands of, among others,nitrogen and phosphorus will become stricter in the near future.

N #$ mg%L current&'& mg%L ne(

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) & mg%L current

$'#* mg%L ne(

Table (. 3urrent and future effluent demand for nitrogen and phosphorus

Cs a result of this de!elopment, post$treatment will be needed in the wastewater treatment

plants. C system using algae forms a good post$treatment system. Clgae take up nitrogen andphosphorus to assimilate into biomass, using readily a!ailable 372and sunlight as carbonsource and energy source.

Clgal biofilms offer se!eral ad!antages o!ersuspended systems as$ biomass is easier to har!est$ no suspended matter in effluent$ low energy re/uirement %no mixing+$ !ertical placement is possible %gi!inghigher photosynthetic efficiency due to light

dilution+

+echnological challenge

The goal of this proAect is to de!elop an algalphoto$biofilm system for the post$treatmentof municipal wastewater. This reactor is

primarily aimed to remo!e residual nitrogenand phosphorus in wastewater.

The challenge is to de!elop a process withhigh nitrogen and phosphorus remo!al during

both day and night. Cnd in addition tominimie the land re/uirement for this

biosolar process by obtaining a highphotosynthetic efficiency.

Secondly, the symbiotic relationship between algae and bacteria in a biofilm can be used. nthis scenario algae and bacteria pro!ide each other with 72and 372, while cleaning theeffluent.

,ulti"ation of Micro Algaentroduction

n commercial algae productionhar!esting is generally done by centrifugation. :owe!er, thecosts and energy demands forhar!esting the algal biomass

by these methods are high. nthe technical and economical analysis on microalgae for biofuels it was shown that thein!estment costs for the centrifuges contributed up to 6=K of the total in!estment on

e/uipment. The study also showed that the centrifuge used =8.8K of the total energy

1! GREEN ALGAE PROJECT

;locculation, ?lobal 4oly$?lu 3o., Htd copyright
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consumption.

n a feasibility study, it was found that the total costs for concentrating the microalgae from).6 g'H to ()) g'H %()K dry matter+ can be reduced from 2.92 uro'kg %for centrifugation+ toabout ).9 uro'kg when the algae are pre$concentrated to 5K dry matter. This can be

achie!ed by flocculation combined with flotation or sedimentation prior to furtherconcentration by centrifugation or filtration. n addition the energy demand decreased from=.9> kh'kg to ).=$).> kh'kg.

;locculation can be achie!ed in different ways %induced flocculation, auto$ andbioflocculation or electroflocculation+, but in general flocculation of the algal biomass is stillpoorly understood. The optimal conditions of the algae and the culture medium needed foreffecti!e flocculation are often unpredictable, which makes it difficult to find ways to controlthe har!esting process. n addition, after har!esting oil needs to be extracted from the

biomass and often the cell wall is a big barrier to facilitate extraction and the thickness of thecell wall is affected by the conditions of the cells at the time of har!esting.

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A feasibility study on the production of

microalgae

;or Felta, an energy companies in the Detherlands, we performed a feasibilitystudy on the production of microalgae, in which 6 production technologies werecompared open pond , horiontal tubular photobioreactor and a flat panel

photobioreactor.The analysis was based on state$of$the$art technology for the solar conditions inthe Detherlands. stimations were conser!ati!e, which means that for reachingestimated producti!ities there is no need to de!elop systems or processes furtherthan what is now possible. n this analysis we also assumed that nutrients for thegrowth medium and 372had to be bought. The end product of the process we

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http://www.algae.wur.nl/UK/technologies/production/commercial_scale_photobioreactors/http://www.algae.wur.nl/UK/technologies/production/commercial_scale_photobioreactors/


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designed is an algal paste with a dry matter content of 2)K. xtraction of oiland esterification was not considered.

Two different plant sies were e!aluated %( and ()) ha+. e report here the

!alues estimated for a scale of ()) ha. #icroalgae biomass can be producedcheaper in photobioreactors than in raceway ponds, but this is achie!ed at theexpense of higher energy consumption. hen comparing the two

photobioreactors, the horiontal tubular reactor and flat panel show a similarbiomass production cost. Gegarding energy balance, flat panels perform a bitbetter, e!en though both systems ha!e a negati!e balance.

There is no practical experience with culti!ation of microalgae for energypurposes. 4hotobioreactors ha!e only been applied for the production ofbiomass of high !alue, i.e. more than ()) 'kg F. Cs a conse/uence,

processes ha!e ne!er been optimied for applications where the !alue ofbiomass is less than ( 'kg F. 4rocess de!elopment for the production ofmicroalgae for energy purposes still needs to be done. n order to analye theeffect of some parameters on biomass ' energy costs a sensiti!ity analysis wasmade. n this way we could determine whether and how costs could berealistically reduced. ith the present status of the technology, production costswere calculated at =.)2 'kg biomass %(56.5 ' ?E+ but could become as low as).=2 'kg biomass %(>.) ' ?E+.Fe!elopment of the technology combined with the usage of the remaining

biomass components, which are not re/uired for biofuel production, in otherapplications %abiorefinery approach in which ())K biomass is !aloried+ thecommercial production of microalgae could become a realistic option for the

biofuel market.

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1# GREEN ALGAE PROJECT
http://www.algae.wur.nl/UK/technologies/biorefinery/http://www.algae.wur.nl/UK/technologies/biorefinery/


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green algae project

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