A method for flocculating of the microscopic particles in suspebsiondans a liquid and application to the collection of the phytoplanctonic microalgues and zooplanton and to the waste water purification.

Vlnvcntioncoacer "" to method pong ** floodsr SAR psrfclmlé microscopic suspended dansas micropump. I->* a " asearaa equalled applying the EO 1 read Forwarding SAR collection method^> T-^< ** ll^T- the W ' living suspended in read *, "KI" mild, ** eaositreaoviiléa nota derivatives chemically active materials of nicroelguesphytoplaBaf constituting the "T-Da are" aSKfriNMteicreecppiqoes constituting the soojplancton. The invention conoarsa&* "" 00 "th" of applying the method to the purification of "to" nor ".

LeemLeroalgnes have " has iaqportant economic benefit, bin launched cell ** - contain large molecules of veleer "such * that substances nédlcasKUbtusee * hydrocarbons (gljroénsl * of" licks Boaaliella vaccinica sarais) "due proteins capable ooarvanic has worn to the atix" vat "" animal is linked Da are also can serve as a substrate for an anaerobic fezsentation DTT-producing methane, not oaSkMNr *

I. esfcdansles lagoon cells for to the épuratisseaax of waste found the concentzatisns ** has the highest

alcroalgues likely to be encountered in nature (200 th these

6, 6

•g/l of prodnit mth with 2.10 to 4.10 cells algsle * by centlaétre cubic). The cleaning process thus gives rise for large prodnctloepcisaite of eicroalgues estimated between 50 and 150 temesgfatfuu EO phytoplankton can be used for the zooplenctonproétairemillimeters for aquaculture (essentially rcrtifères, and Daphnia oopépode *), * animatuc AE groups of food is a sequence suitable fear food of juvenile of crustaceans and poisseras, mIMM 1 séqptence producing the food, by the T ethnic current * is expensive, sophisticated and delicate to control.

The BN fact " the problem the more delicate laid parada *

in ES<NRs grams

technical " which constituting my © ©&will⁵ use of solar energy₉Qot 1®, © © 11andm® d. @ e ssicroalgues.

The ISS is illustrate®. difficulties of economy that raises this collection ". © e. © e with reference to the methanization of Eticrophytesa technique which "in the field of producing renewable © d * 4u © ROI" lifts a heightened interest from qeelqne © # years

In the case 1 © more favorable - control of espècescollectées "harvested by techniques requiring the lowest powers" afesamc® drying - " OD raw energy producing algal (total amount of enthalpy used © for © aintanir the production system operating from natural raw materials) is of the order üq U.S. MJ is/kg." methanogenic by fermentation, can be reoperation?<SGs/s of the net calorific value - © heat collected by combustion " 1¹ water formed being state of O vapsuro®■calorific value amounting to 23 "2/MJ is output comprises" © ITs 13th 9 MJ is the O/kg body weight. This means "for example" that a ssasso © kg OD e microphytes produces 1 FPG eSP icétsssssieaêisæa,, shivering QPs® its production that required 1"&%<Sj and₂ lo and overall energy balance is negative "due" essentially " the complexity of the separation of the microphytes of the aqueous medium.

Due. their dimensions (10 - 30 pœ) and of. their specific characteristics (living organisms) "microscopic algae pose" © has © ffst " of difficult problems. some methods of séparatiosv already tested have been found or poorly or big energy consumers (i.e. 1 © "e 4 © the centrifugal decanting or thence flotation, tested. large © scale for separation of plankton)"

In the treatment of® drinking water waters "the mierotamisage is used for svo® success from of nombreu *" thereof. years "with per-objective a priori of Ta-IR-© 1•removal '- - algae * materials © suspension removed © © are recovered in a state utilizing gluS @® UEs © trea l." usages under' ferae ID.' a liquid - filled eucera ER. Sstivasosit louse (tand; © D.

i-concentrating " 3 to 20 θ).

With the filtration on granular material, enhanced results are achieved, but at the cost of consuming high energy plane. Here also, a recuperated " except the suspended materials retained is envisioned * wheat with a concentration level of 20 to 30 *

The performance of certain methods cited can be improved by adding chemical reactants for flocculating the algae. But this significantly increases the cost of pro - * decrease and may compromise the use of the product in a sequence food.

Accordingly, if a concentrated suspension of a few grams to a few tens of grams per liter of interest, methods such as Microstraining or filtration can be applied. If a higher concentration should be reached, it does not exist until update method in conformity with the technical and economic requirements.

The present invention aims to remedy these drawbacks by proposing a method for flocculating the microalgae or other organic particles having adjacent properties without adding reagents, moysxmam * low power consumption, and with a modifiestion physical properties of these microalgae such as a simple settling will exceed the concentration levels of the order of 100 and this, without impairing their nutritional qualities.

0 recalls that the flocculation is a complex phenomenon which results in the formation of flakes, it is say a net structure and porous. Under the denomination is often confused phenomena of coagulating and true, which have the effect of creating aggregates readily separable. By way of example, the physico-chemical treatment wastewater c=7

from any origin comprised a © w&As® floeula -

except_/ which is © btenus by addXtica e - "© has © to of SU suitable reagent fckicrar © farriqu © ^ ssifat ©'d ^ alusainiusa * polyéleetrolytes @ m further} and being followed by © CMBs® ASU® pbasa separation liquid expanding ©<=e @ LID energies by décantatien ©"

This clarification by ficcuXaticKi © jmrticu CD - "' lièreaient useful in. 1q TSAs&toEsSîstë © e® aœsseêa&'d be rate, highly variable, excluding the ospi ©.! of the I @ giquprceédês cat © "@ traditionnelso its revends ©, OA subtype ©'d © will handle, présc®" T-<te the carved disadvantage⁸ '* âts © IC " its © would have high_C. <âa fact of consumption of FL® C.® lati® has<,

The inventor devised a method to achieve flocculation && particles. The R® O © @ @ IAE spikes © has suspension in a liquid, which can be applied. advantageously the mutual interest © Bierccnganisaes of living and has ©.

not require the X¹ adding the I'd © ©<réactifgsflcculatiea.

The L * invention by © © saséepaiat w @ throughput using a method for flocuier particles® © I-R-n-piqu © e © © © 3®suspansics in a liquid © " characterized OSAs AE rívetted © L.^B © M is has passed a first liquid■© @® RA © nsnt particles aicrcs © © - " like barbs to head suspension through the granular media■eclissatage fixed bed up® to partial or. complete said caHeu granular lesâiè.ss © e piquaier® particles is®₅ in e © that dêaclsat © has® less' partially said Eakliou

© © e - granulaiir FISs bed © ' by passing it through a seqond 1 © antilock ©, @ 1 © eireulaat in SMEs sounds that 1 © © first liquid_restorative © May © to a higher speed to calai - © " © *! and " © rívetted © L-n-C.⁸ © n-recovers its downstream of said bed, in the direction of flow of said liquid "of aggregate © fXoesié © said microscopic particles TDC the m liquid influent, pasrfc&elieeanæat © its totally lifers ' desditos particles"

The S © th © UDs liquid will rather ICL=AE © e © back bicycle inside e © © endpin suspending and STR © © * @ has a V®>' tuellessent identical to first liquid © have served to clog 1 © garlic! ^ aarnlairoo ClO © U-lock®, © has parts© τ!! 1 © © aces 1 © s * o D.⁰ the SMS to SIS © © has © © savro © has © catia® PP © © die according 1 * invention I, in which case a portion of 1 * effluent containing optionally the floc may be recycled to L¹ supply of the granular media.

Mainly in the case of a continuous implementation of the method according to the invention, the granular medium will remain fixed or expand the NA most about 3Gfo in the volume, the granular media now fluidized state.

The granular medium may advantageously be made of particles with a particle size of between about 3 cm and 0,005 and density of about

O

1.1 gm/CNR or more. The exact dimensions and the

nature of the particles, as well as the speed of the traverse of the granular medium, generally between the O, 1 and 5 m/h (eBCT speed), will be selected according to the treated slurry and the desired result.

As granular medium, may be used provided simply natural sand. Also can utilize other particles, sharp or rounded, for example ceramics particles or calcined clay and ground.

Advantageously, this method may be implemented in a vertical column or inclined, cylindrical or spiral, containing the granular media. This colorme will be fed at its base by the liquid to be treated, while the aggregates of flocculated particles will be recovered to a level higher than that of the granular media and effluent scrubbing liquid will drain out to an even higher level. Although this form of implementation of the method according to the invention is preferred, yet can apply this stream down.

Preferably, to promote concentration of the floc, the portion of the column where it will be recovered, in upward flow, will have a surface section upper than the part containing the granular media.

Mainly in its application to the collection of microalguaa or zooplankton, the method in conformity © to I^O © present invention will comprise at least one additional phase concentration of floeulats separate granular media, e.g. by décantationj optionally, as it is just indicated, even within the column in which the process is carried out its " recovery can also use other means of concentrating conans in the technique, which can not be usually collect aicr © algae® U of the sooplan-to-ONTC is suspended, due to the minute concentration of Da and the suspensions.

In its application to the purification and thence to purify waste water, 1 © method, according to the invention does not require the d® reagents OD fiosulation and will therefore be much meinseoôteus that usual methods comprising a step d® flocculation.

Figures 1 and 2 of the accompanying drawings are diagrams illustrating two forms of put © n-& © © in conformity of the method preferred opens to the invention.

Figure 3 illustrates another eplerenone SU © ©'d © usages® therefor.

Gustatory first to Figure 1, on which see a column 1, wherein © CD housed a granular bed 2 a material having such, the density and the particle size is chosen based on the result. desired and slurry to treat "it may be constituted -, for example, D. © natural sand■(quartz and quartzite) D. © granulometri © comprised between 0.2 and 4 mm ©"

The granular bed 2 is supplied with liquid by a line 3 connected to the low-© © the column "

Initially, © © food has the granular bed 2 through line 3 with a liquid containing minute particles suspended © N., which can be the same as or different liquid expanding © to postponed and this 12 thus to a soundproofing © © th © liquid through the ts "bed FISs ©'d © partieml © e solid" © has therefore causes progressive clogging aces * of the bed 2 and L * is determined each increase in the pressure drop through the bed " is stopped 1' power when this pressure reaches a predetermined value, corresponding to partial clogs the bed 2, or optionally after clogging oonplet of this bed. In tests performed by 1⁵ inventor " the pressure drop corresponding to a colsaatage satisfying the bed 2 was of 1•' order of 50 cm OS height of water per meter of height of the granular bed.

The granular bed 2 having thus been treated " can be used to achieve flocculation in contained a suspension of microscopic particles such as microalgae " which can be different than the suspension was used to occlude the bed 2.

The suspension is injected through the traitor line 3 at the base of the oslcomo 1 at a speed higher than that of the suspension previously used for plugging the granular bed and the range, typically, of 0.1 to 5 meters/an HO

Such surprising®, is observed, to the output of the granular bed 2₉ the formation of a floc microscopic particles of the suspension. The flakes may have dimensions of between 1 and 5 mm and, by decantation, they OS separate at the top of the column 1 by forming a coueh © 4, which can be evacuated, intermittently or @ n-continuous "by a line 5" this layer 4 floc is topped by a layer 6 blocking liquid * cleaned at least in part_{the P} that is discharged by the line 7. At least a portion of said liquid effluent incidentally andR © © recirculated by a pump 8 and by the visitors of 7a to the line of alisentation * 3 to recover the floc êir © present there in.

I © granular bed 2 having undergone the pretreatment of partial clogs @ U-the total may then be used continuously for the ISS fioeuier microscopic particles present in - feed suspension. The metastability "4" in Figures 1 and 2 illustrate a preferred implementation a MFC the invention, in which the granular bed 2 or 2' is traversed by an upward flow of liquid to be treated "

The invention may however be implemented, also, with a granular bed traversed from top to bottom by the suspension of microscopic particles to floua "1st"

Figure 3 illustrates this implementation * in this variant, the column 11, containing a granular bed 12, 13 is fed with, at its top, liquid containing minute particles suspended " the effluent containing the flakes of flocculated particles is discharged to the base of column 11, 14 by a line, in the direction of the¹ lower part of a settler upright 15 * 15 in the settler, the effluent from the column 11 is countercurrent to the floc 16 of microscopic particles, which accumulates at the bottom of the settler 15 and is discharged through a line 17 "the liquid partially cleaned is discharged to the top of the settler not 15? a line 18 and a portion of the liquid may be optionally recycled, as previously, by a line 19 and a pump 20 to the line 13 column feed 11"

The following examples illustrate various applications of the method according to the invention.

SUCH AS I

This example concerns the application of the above method to the collection of microalgae phytoplankton * suspended in water.

Various tests have been carried out, with different types of granular bed, in a vertical column to upward flow, an area dELC - suspended sicroalguesdaxta of 1' water•

The following table collects the results of such testing and exemplified the effectiveness of the method according to 1 * invent ion battery.

<e " c3

This table®, 1 illustrates⁵ efficiency of the method according to the invention T-Esoatre ©, © e particular, a granular bed consisting of large-grained ground calcined clay (3 to 5 k3) © St.₉ d. © surprisingly "" particularly benefit₅ for implementing concurrent process "

The invention provides there.was simple, easy hr implementing ' and FSIP cost had "to concentrate suspensions to very low concentration of microscopic particles" 11 is clear that "in its application Ilya collecta microalgae or zooplankton, the method is particularly attractive, since it does not destroy the physicochemical properties of microorganisms récupéréso as they remain living in their natural environment" built during the whole duration of the © © sHsentrssfciosü and mutual interest® *

THE II ESEMPLE

This AE® APIs © eoaesao 1⁹ use of the process 1⁸ invention to the purification of sewage of urban waste has undergone preliminary clarification by simple déoaatatioa₀

These waters, having flush material concentration of "suspended varying between 150 and 200 mg/liter, pass through a bed glued of sand with a particle size of 300 MW, water" addition of any reagent d-® flocculation "

0a score its expansion ratio of the sand bed of 10j (" © found as the natural materials in suspension are retained for a dwell time of one hour, while fQfs OD its materials are retained with a time of passages D. © trcis hours.

Particulates retained constitute a flocculate which Séjp © -§© to the surfaca of the granular bed * this floc w&cyle © © tee élisiîaé periodically or continuously