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Mphepo yamkuntho ya fumbi imawopseza kwambiri mayiko ambiri padziko lonse lapansi chifukwa cha kuwononga kwake ulimi, thanzi la anthu, maukonde oyendera ndi zomangamanga. Chifukwa chake, kuwonongeka kwa mphepo kumaonedwa ngati vuto lapadziko lonse lapansi. Njira imodzi yosamalira chilengedwe yochepetsera kuwonongeka kwa mphepo ndi kugwiritsa ntchito microbial induced carbonate precipitation (MICP). Komabe, zotsatira za MICP yochokera ku urea-degradation-based MICP, monga ammonia, sizoyenera zikapangidwa zambiri. Kafukufukuyu akuwonetsa mitundu iwiri ya mabakiteriya a calcium formate kuti awononge MICP popanda kupanga urea ndipo akuyerekeza bwino momwe amagwirira ntchito ndi mitundu iwiri ya mabakiteriya a calcium acetate omwe sapanga ammonia. Mabakiteriya omwe akuganiziridwa ndi Bacillus subtilis ndi Bacillus amyloliquefaciens. Choyamba, kuchuluka kwa zinthu zomwe zimalamulira kupanga CaCO3 kudadziwika. Mayeso a ngalande ya mphepo adachitika pa zitsanzo za mchenga zomwe zidathandizidwa ndi mitundu yokonzedwa bwino, ndipo kukana kuwonongeka kwa mphepo, kuthamanga kwa mtunda, ndi kukana kuphulika kwa mchenga zidayesedwa. Ma allomorph a Calcium carbonate (CaCO3) adayesedwa pogwiritsa ntchito maikulosikopu optical, scanning electron microscopy (SEM), ndi X-ray diffraction analysis. Ma formula opangidwa ndi calcium formate adachita bwino kwambiri kuposa ma formula opangidwa ndi acetate pankhani ya kapangidwe ka calcium carbonate. Kuphatikiza apo, B. subtilis idapanga calcium carbonate yambiri kuposa B. amyloliquefaciens. Ma micrograph a SEM adawonetsa bwino momwe mabakiteriya ogwira ntchito komanso osagwira ntchito amamangirira komanso amasindikizidwa pa calcium carbonate yomwe imayambitsidwa ndi sedimentation. Ma formula onsewa adachepetsa kwambiri kukokoloka kwa mphepo.
Kusefukira kwa mphepo kwakhala kukudziwika kwa nthawi yayitali ngati vuto lalikulu lomwe likukumana ndi madera ouma komanso ouma pang'ono monga kum'mwera chakumadzulo kwa United States, kumadzulo kwa China, Saharan Africa, ndi madera ambiri a Middle East1. Mvula yochepa m'madera ouma komanso ouma kwambiri yasintha madera ambiri kukhala zipululu, milu ya mchenga, ndi malo osalimidwa. Kusefukira kwa mphepo kosalekeza kumabweretsa ziwopsezo zachilengedwe ku zomangamanga monga maukonde oyendera, malo olima, ndi malo a mafakitale, zomwe zimapangitsa kuti pakhale moyo wosauka komanso ndalama zambiri zoyendetsera mizinda m'maderawa2,3,4. Chofunika kwambiri, kusefukira kwa mphepo sikumangokhudza malo omwe kumachitika, komanso kumayambitsa mavuto azaumoyo ndi zachuma m'madera akutali chifukwa kumanyamula tinthu tating'onoting'ono ndi mphepo kupita kumadera akutali ndi komwe kumachokera5,6.
Kuwongolera kukokoloka kwa mphepo kukupitirirabe kukhala vuto lapadziko lonse. Njira zosiyanasiyana zokhazikitsira nthaka zimagwiritsidwa ntchito poletsa kukokoloka kwa mphepo. Njirazi zikuphatikizapo zinthu monga kugwiritsa ntchito madzi7, ma mulch a mafuta8, ma biopolymer5, microbial induced carbonate precipitation (MICP)9,10,11,12 ndi enzyme induced carbonate precipitation (EICP)1. Kunyowetsa nthaka ndi njira yodziwika bwino yochepetsera fumbi m'munda. Komabe, kuuluka kwake mwachangu kumapangitsa kuti njira iyi ikhale yogwira ntchito pang'ono m'madera ouma komanso ouma pang'ono1. Kugwiritsa ntchito ma compounds a mulching mafuta kumawonjezera mgwirizano wa mchenga ndi kukangana pakati pa tinthu tating'onoting'ono. Kugwirizana kwawo kumalumikiza tirigu wa mchenga pamodzi; komabe, ma mulch a mafuta amabweretsanso mavuto ena; mtundu wawo wakuda umawonjezera kuyamwa kwa kutentha ndipo umatsogolera ku imfa ya zomera ndi tizilombo toyambitsa matenda. Fungo lawo ndi utsi wawo zimatha kuyambitsa mavuto opuma, ndipo makamaka, mtengo wawo wokwera ndi chopinga china. Ma biopolymer ndi imodzi mwa njira zomwe zaperekedwa posachedwapa kuti zichepetse kukokoloka kwa mphepo; amachotsedwa kuzinthu zachilengedwe monga zomera, nyama ndi mabakiteriya. Xanthan chingamu, guar chingamu, chitosan ndi gellan chingamu ndi ma biopolymer omwe amagwiritsidwa ntchito kwambiri mu ntchito zaukadaulo5. Komabe, ma biopolymers osungunuka m'madzi amatha kutaya mphamvu ndikutuluka m'nthaka akakumana ndi madzi13,14. EICP yawonetsedwa kuti ndi njira yothandiza yochepetsera fumbi pazinthu zosiyanasiyana kuphatikizapo misewu yopanda miyala, maiwe a m'mphepete mwa nyanja ndi malo omanga. Ngakhale kuti zotsatira zake ndi zolimbikitsa, zovuta zina ziyenera kuganiziridwa, monga mtengo ndi kusowa kwa malo opangira ma nucleation (zomwe zimafulumizitsa kupanga ndi kugwetsa makristalo a CaCO315,16).
MICP idafotokozedwa koyamba kumapeto kwa zaka za m'ma 1800 ndi Murray ndi Irwin (1890) ndi Steinmann (1901) mu kafukufuku wawo wokhudza kuwonongeka kwa urea ndi tizilombo toyambitsa matenda a m'nyanja17. MICP ndi njira yachilengedwe ya zamoyo yomwe imakhudza ntchito zosiyanasiyana za tizilombo toyambitsa matenda komanso njira zamakemikolo momwe calcium carbonate imayambitsidwira ndi momwe ma carbonate ions amagwirira ntchito kuchokera ku ma metabolites a tizilombo toyambitsa matenda omwe ali ndi ma calcium ions m'chilengedwe18,19. MICP yokhudza urea-degrading nitrogen cycle (urea-degrading MICP) ndi mtundu wofala kwambiri wa microbial-induced carbonate precipitation, momwe ureaase yopangidwa ndi mabakiteriya imayambitsa hydrolysis ya urea20,21,22,23,24,25,26,27 motere:
Mu MICP yokhudzana ndi kayendedwe ka kaboni ka okosijeni wa mchere wachilengedwe (MICP yopanda mtundu wa kuwonongeka kwa urea), mabakiteriya a heterotrophic amagwiritsa ntchito mchere wachilengedwe monga acetate, lactate, citrate, succinate, oxalate, malate ndi glyoxylate ngati magwero a mphamvu kuti apange mchere wa carbonate28. Pakakhala calcium lactate ngati gwero la kaboni ndi ma calcium ions, momwe mankhwala amagwirira ntchito popanga calcium carbonate akuwonetsedwa mu equation (5).
Mu njira ya MICP, maselo a bakiteriya amapereka malo ofunikira kwambiri pakugwa kwa calcium carbonate; pamwamba pa maselo a bakiteriya pali mphamvu yoipa ndipo imatha kugwira ntchito ngati chokometsera ma cation osiyanasiyana monga ma calcium ion. Mwa kukoka ma calcium ion pamaselo a bakiteriya, pamene kuchuluka kwa ma ion a carbonate kuli kokwanira, ma calcium cation ndi ma carbonate anions amachitapo kanthu ndipo calcium carbonate imagwera pamwamba pa bakiteriya29,30. Njirayi itha kufotokozedwa motere31,32:
Makristalo a calcium carbonate opangidwa ndi biogenerated akhoza kugawidwa m'mitundu itatu: calcite, vaterite, ndi aragonite. Pakati pawo, calcite ndi vaterite ndi ma allomorphs a calcium carbonate omwe amapezeka kwambiri chifukwa cha bakiteriya33,34. Calcite ndiye allomorphs a calcium carbonate okhazikika kwambiri pa thermodynamically. Ngakhale kuti vaterite yanenedwa kuti ndi yokhazikika, pamapeto pake imasintha kukhala calcite36,37. Vaterite ndiye wokhuthala kwambiri mwa makristalo awa. Ndi kristalo wa hexagonal womwe uli ndi mphamvu yabwino yodzaza ma pore kuposa makristalo ena a calcium carbonate chifukwa cha kukula kwake kwakukulu38. MICP yonse ya urea-degraded ndi urea-undegraded ingayambitse kugwa kwa vaterite13,39,40,41.
Ngakhale kuti MICP yawonetsa kuthekera kolimbikitsa kukhazikika kwa nthaka ndi nthaka zovuta zomwe zimakhudzidwa ndi kukokoloka kwa mphepo42,43,44,45,46,47,48, chimodzi mwa zinthu zomwe zimapangitsa kuti urea hydrolysis iwonongeke ndi ammonia, yomwe ingayambitse mavuto azaumoyo pang'ono mpaka akulu kutengera kuchuluka kwa kukhudzidwa49. Zotsatira zake zimapangitsa kuti kugwiritsa ntchito ukadaulo uwu kukhale kotsutsana, makamaka pamene madera akuluakulu amafunika kukonzedwa, monga kuletsa fumbi. Kuphatikiza apo, fungo la ammonia silingatheke pamene njirayi ikuchitika pamlingo wapamwamba komanso kuchuluka kwakukulu, zomwe zingakhudze momwe imagwiritsidwira ntchito. Ngakhale kuti kafukufuku waposachedwapa wasonyeza kuti ma ayoni a ammonium amatha kuchepetsedwa powasandutsa zinthu zina monga struvite, njirazi sizichotsa kwathunthu ma ayoni a ammonium50. Chifukwa chake, pakadali kufunikira kufufuza njira zina zomwe sizipanga ma ayoni a ammonium. Kugwiritsa ntchito njira zosakhala za urea za MICP kungapereke yankho lomwe silinafufuzidwe bwino pankhani yochepetsa kukokoloka kwa mphepo. Fattahi et al. anafufuza za kuwonongeka kwa MICP kopanda urea pogwiritsa ntchito calcium acetate ndi Bacillus megaterium41, pomwe Mohebbi ndi ena anagwiritsa ntchito calcium acetate ndi Bacillus amyloliquefaciens9. Komabe, kafukufuku wawo sunayerekezedwe ndi magwero ena a calcium ndi mabakiteriya a heterotrophic omwe pamapeto pake angathandize kukana kukokoloka kwa nthaka ndi mphepo. Palinso kusowa kwa mabuku oyerekeza njira zopanda kukokoloka kwa nthaka ndi njira za urea pochepetsa kukokoloka kwa nthaka ndi mphepo.
Kuphatikiza apo, kafukufuku wambiri wokhudza kukokoloka kwa nthaka ndi fumbi wachitika pa zitsanzo za nthaka yokhala ndi malo athyathyathya.1,51,52,53 Komabe, malo athyathyathya sapezeka kawirikawiri m'chilengedwe monga mapiri ndi malo otsetsereka. Ichi ndichifukwa chake milu ya mchenga ndi malo odziwika kwambiri m'madera achipululu.
Pofuna kuthana ndi zofooka zomwe tatchulazi, kafukufukuyu cholinga chake chinali kuyambitsa gulu latsopano la mabakiteriya osapanga ammonia. Pachifukwa ichi, tinaganizira njira za MICP zosawononga urea. Kugwira ntchito bwino kwa magwero awiri a calcium (calcium formate ndi calcium acetate) kunafufuzidwa. Malinga ndi zomwe olembawo akudziwa, kupopera kwa carbonate pogwiritsa ntchito magwero awiri a calcium ndi mabakiteriya (monga calcium formate-Bacillus subtilis ndi calcium formate-Bacillus amyloliquefaciens) sikunafufuzidwe m'maphunziro am'mbuyomu. Kusankha mabakiteriyawa kunachokera ku ma enzyme omwe amapanga omwe amachititsa kuti calcium formate ndi calcium acetate ziwonjezeke kuti apange kupopera kwa microbial carbonate. Tinapanga kafukufuku wozama kuti tipeze zinthu zabwino kwambiri monga pH, mitundu ya mabakiteriya ndi magwero a calcium ndi kuchuluka kwawo, chiŵerengero cha mabakiteriya ku yankho la calcium komanso nthawi yochira. Pomaliza, mphamvu ya mabakiteriya amenewa poletsa kukokoloka kwa mphepo kudzera mu calcium carbonate precipitation inafufuzidwa mwa kuchita mayeso angapo a mphepo pa ming'alu ya mchenga kuti adziwe kukula kwa kukokoloka kwa mphepo, liwiro la kusweka kwa mchenga ndi kukana kwa mphepo, komanso kuyeza kwa penetrometer ndi maphunziro a microstructural (monga X-ray diffraction (XRD) analysis ndi scanning electron microscopy (SEM)) zinachitidwanso.
Kupanga calcium carbonate kumafuna ma calcium ion ndi ma carbonate ion. Ma calcium ion angapezeke kuchokera ku magwero osiyanasiyana a calcium monga calcium chloride, calcium hydroxide, ndi skim milk powder54,55. Ma carbonate ion amatha kupangidwa pogwiritsa ntchito njira zosiyanasiyana za microbial monga urea hydrolysis ndi aerobic kapena anaerobic oxidation of organic matter56. Mu kafukufukuyu, ma carbonate ion adapezeka kuchokera ku oxidation reaction ya formate ndi acetate. Kuphatikiza apo, tidagwiritsa ntchito calcium salts ya formate ndi acetate kuti tipange calcium carbonate yoyera, motero CO2 ndi H2O zokha ndi zomwe zidapezeka ngati zotsalira. Munjira iyi, chinthu chimodzi chokha chimagwira ntchito ngati gwero la calcium ndi gwero la carbonate, ndipo palibe ammonia yomwe imapangidwa. Makhalidwe awa amapangitsa njira yopanga calcium ndi carbonate yomwe tidaganiza kuti ndi yodalirika kwambiri.
Machitidwe ofanana a calcium formate ndi calcium acetate kuti apange calcium carbonate akuwonetsedwa mu ma formula (7)-(14). Ma formula (7)-(11) akuwonetsa kuti calcium formate imasungunuka m'madzi kuti ipange formic acid kapena formate. Chifukwa chake yankho ndi gwero la ma ion a calcium ndi hydroxide aulere (ma formula 8 ndi 9). Chifukwa cha okosijeni wa formic acid, maatomu a carbon mu formic acid amasinthidwa kukhala carbon dioxide (formula 10). Calcium carbonate pamapeto pake imapangidwa (ma formula 11 ndi 12).
Mofananamo, calcium carbonate imapangidwa kuchokera ku calcium acetate (ma equation 13-15), kupatula kuti acetic acid kapena acetate imapangidwa m'malo mwa formic acid.
Popanda kukhalapo kwa ma enzyme, acetate ndi formate sizingapangidwe kukhala oxidized pa kutentha kwa chipinda. FDH (formate dehydrogenase) ndi CoA (coenzyme A) zimayambitsa oxidization ya formate ndi acetate kuti apange carbon dioxide, motsatana (Eqs. 16, 17) 57, 58, 59. Mabakiteriya osiyanasiyana amatha kupanga ma enzyme awa, ndipo mabakiteriya a heterotrophic, omwe ndi Bacillus subtilis (PTCC #1204 (Persian Type Culture Collection), omwe amadziwikanso kuti NCIMB #13061 (International Collection of Bacteria, Yeast, Phage, Plasmids, Plant Seeds and Plant Cell Tissue Cultures)) ndi Bacillus amyloliquefaciens (PTCC #1732, NCIMB #12077), adagwiritsidwa ntchito mu kafukufukuyu. Mabakiteriya awa adalimidwa mu sing'anga yokhala ndi meat peptone (5 g/L) ndi meat extract (3 g/L), yotchedwa nutrient broth (NBR) (105443 Merck).
Motero, njira zinayi zinakonzedwa kuti zipangitse kuti calcium carbonate igwere pogwiritsa ntchito magwero awiri a calcium ndi mabakiteriya awiri: calcium formate ndi Bacillus subtilis (FS), calcium formate ndi Bacillus amyloliquefaciens (FA), calcium acetate ndi Bacillus subtilis (AS), ndi calcium acetate ndi Bacillus amyloliquefaciens (AA).
Mu gawo loyamba la kapangidwe ka kafukufuku, mayeso adachitika kuti adziwe kuphatikiza kwabwino kwambiri komwe kungapangitse kupanga calcium carbonate yambiri. Popeza zitsanzo za nthaka zinali ndi calcium carbonate, mayeso oyeserera oyamba adapangidwa kuti ayesere molondola CaCO3 yopangidwa ndi kuphatikiza kosiyanasiyana, ndipo zosakaniza za njira zokulira ndi njira zopezera calcium zidayesedwa. Pa kuphatikiza kulikonse kwa njira yopezera calcium ndi mabakiteriya yomwe yafotokozedwa pamwambapa (FS, FA, AS, ndi AA), zinthu zowongolera (kuchuluka kwa calcium, nthawi yochira, kuchuluka kwa mabakiteriya omwe amayesedwa ndi kuchuluka kwa optical kwa yankho (OD), chiŵerengero cha njira yopezera calcium ndi mabakiteriya, ndi pH) zidatengedwa ndikugwiritsidwa ntchito mu mayeso a mphepo ya mchenga omwe afotokozedwa m'magawo otsatirawa.
Pa kuphatikiza kulikonse, mayeso 150 adachitika kuti aphunzire momwe CaCO3 imakhudzira mvula ndikuwunika zinthu zosiyanasiyana, monga kuchuluka kwa calcium source, nthawi yochira, kuchuluka kwa OD ya bakiteriya, kuchuluka kwa calcium source to bacterial solution ratio ndi pH panthawi ya aerobic oxidation ya organic matter (Table 1). Mtundu wa pH wa njira yabwino kwambiri unasankhidwa kutengera kukula kwa Bacillus subtilis ndi Bacillus amyloliquefaciens kuti apeze kukula mwachangu. Izi zafotokozedwa mwatsatanetsatane mu gawo la Zotsatira.
Njira zotsatirazi zinagwiritsidwa ntchito pokonzekera zitsanzo za gawo lokonzekera bwino. Yankho la MICP linakonzedwa poyamba mwa kusintha pH yoyambirira ya malo osungiramo zinthu kenako nkuyikidwa pa 121 °C kwa mphindi 15. Kenako vutolo linayikidwa mu mpweya wa laminar ndikusungidwa mu incubator yogwedeza pa 30 °C ndi 180 rpm. OD ya mabakiteriya ikafika pamlingo womwe ukufunika, idasakanizidwa ndi yankho la calcium source mu gawo lomwe likufunika (Chithunzi 1a). Yankho la MICP linaloledwa kuchitapo kanthu ndikulimba mu incubator yogwedeza pa 220 rpm ndi 30 °C kwa nthawi yomwe idafika pamtengo womwe ukuyembekezeka. CaCO3 yokhazikika idalekanitsidwa pambuyo pa centrifugation pa 6000 g kwa mphindi 5 kenako nkuumitsidwa pa 40 °C kuti akonze zitsanzo za mayeso a calcimeter (Chithunzi 1b). Kuchuluka kwa mpweya wa CaCO3 kunayesedwa pogwiritsa ntchito calcimeter ya Bernard, pomwe ufa wa CaCO3 umakumana ndi 1.0 N HCl (ASTM-D4373-02) kuti upange CO2, ndipo kuchuluka kwa mpweya uwu ndi muyeso wa kuchuluka kwa CaCO3 (Chithunzi 1c). Kuti asinthe kuchuluka kwa CO2 kukhala kuchuluka kwa CaCO3, njira yowunikira idapangidwa potsuka ufa wa CaCO3 woyera ndi 1 N HCl ndikuwupanga motsutsana ndi CO2 yomwe idasinthidwa. Kapangidwe ndi kuyera kwa ufa wa CaCO3 wokhazikika zidafufuzidwa pogwiritsa ntchito SEM imaging ndi XRD analysis. Maikulosikopu yowala yokhala ndi kukula kwa 1000 idagwiritsidwa ntchito pophunzira kapangidwe ka calcium carbonate mozungulira mabakiteriya, gawo la calcium carbonate yopangidwa, ndi ntchito ya mabakiteriya.
Dejegh Basin ndi dera lodziwika bwino lomwe lawonongeka kwambiri kum'mwera chakumadzulo kwa Fars Province ku Iran, ndipo ofufuzawo adasonkhanitsa zitsanzo za nthaka yowola ndi mphepo kuchokera kuderali. Zitsanzozo zidatengedwa kuchokera pamwamba pa nthaka kuti akafufuze. Mayeso owonetsa zitsanzo za nthaka adawonetsa kuti nthakayo inali yopanda kusankhidwa bwino ndi dothi lamchenga lokhala ndi matope ndipo adayikidwa m'gulu la SP-SM malinga ndi Unified Soil Classification System (USC) (Chithunzi 2a). Kusanthula kwa XRD kudawonetsa kuti nthaka ya Dejegh inali yopangidwa makamaka ndi calcite ndi quartz (Chithunzi 2b). Kuphatikiza apo, kusanthula kwa EDX kudawonetsa kuti zinthu zina monga Al, K, ndi Fe nazonso zinalipo pang'ono.
Pofuna kukonzekera milu ya m'ma laboratories kuti ayesere kukokoloka kwa nthaka ndi mphepo, nthaka inaphwanyidwa kuchokera kutalika kwa 170 mm kudzera mu funnel ya mainchesi 10 mm kupita pamwamba pa nthaka yolimba, zomwe zinapangitsa kuti milu ya m'ma mainchesi 60 mm ikhale yayitali komanso 210 mm mulifupi. Mwachilengedwe, milu ya mchenga yocheperako imapangidwa ndi njira za aeolian. Mofananamo, chitsanzo chomwe chinakonzedwa pogwiritsa ntchito njira yomwe ili pamwambapa chinali ndi kuchuluka kochepa kwambiri, γ = 14.14 kN/m³, kupanga cone ya mchenga yomwe inayikidwa pamalo opingasa okhala ndi ngodya yopumula ya pafupifupi 29.7°.
Yankho labwino kwambiri la MICP lomwe linapezeka m'gawo lapitalo linathiridwa pa phiri la dune pamlingo wa 1, 2 ndi 3 lm-2 kenako zitsanzozo zinasungidwa mu incubator pa 30 °C (Chithunzi 3) kwa masiku 9 (kutanthauza nthawi yabwino kwambiri yophikira) kenako nkutengedwa kuti akayesedwe ndi ngalande ya mphepo.
Pa chithandizo chilichonse, zitsanzo zinayi zinakonzedwa, chimodzi choyezera kuchuluka kwa calcium carbonate ndi mphamvu ya pamwamba pogwiritsa ntchito penetrometer, ndipo zitsanzo zitatu zotsalazo zinagwiritsidwa ntchito poyesa kukokoloka kwa nthaka pa liwiro losiyana la mitundu itatu. Mu mayeso a ngalande ya mphepo, kuchuluka kwa kukokoloka kwa nthaka kunadziwika pa liwiro losiyana la mphepo, kenako liwiro lothawirapo la chitsanzo chilichonse chochiritsira linadziwika pogwiritsa ntchito chigawo cha kuchuluka kwa kukokoloka kwa nthaka poyerekeza ndi liwiro la mphepo. Kuwonjezera pa mayeso a kukokoloka kwa nthaka ya mphepo, zitsanzo zomwe zinachiritsidwa zinachitidwa mabomba a mchenga (monga, kuyesa kulumpha). Zitsanzo zina ziwiri zinakonzedwa pachifukwa ichi pamlingo wogwiritsidwa ntchito wa 2 ndi 3 L m−2. Mayeso a mabomba a mchenga adatenga mphindi 15 ndi flux ya 120 gm−1, yomwe ili mkati mwa miyeso yomwe idasankhidwa m'maphunziro am'mbuyomu 60,61,62. Mtunda wopingasa pakati pa nozzle yovunda ndi maziko a ngalande unali 800 mm, womwe uli 100 mm pamwamba pa pansi pa ngalande. Malo awa adakhazikitsidwa kotero kuti pafupifupi tinthu tonse ta mchenga todumphadumpha tinagwera pa ngalande.
Kuyesa kwa ngalande ya mphepo kunachitika mu ngalande yotseguka ya mphepo yokhala ndi kutalika kwa mamita 8, m'lifupi mwake mamita 0.4 ndi kutalika kwa mita imodzi (Chithunzi 4a). Ngalande ya mphepo imapangidwa ndi mapepala achitsulo opangidwa ndi galvanized ndipo imatha kupanga liwiro la mphepo mpaka 25 m/s. Kuphatikiza apo, chosinthira ma frequency chimagwiritsidwa ntchito kusintha ma frequency a fan ndikuwonjezera pang'onopang'ono ma frequency kuti mupeze liwiro la mphepo yomwe mukufuna. Chithunzi 4b chikuwonetsa chithunzi cha schematic cha milu ya mchenga yomwe yawonongeka ndi mphepo ndi mbiri ya liwiro la mphepo yomwe imayesedwa mu ngalande ya mphepo.
Pomaliza, kuti tiyerekeze zotsatira za njira ya MICP yopanda urealytic yomwe yaperekedwa mu kafukufukuyu ndi zotsatira za mayeso owongolera a urealytic MICP, zitsanzo za dune zinakonzedwanso ndikuchiritsidwa ndi yankho lachilengedwe lomwe lili ndi urea, calcium chloride ndi Sporosarcina pasteurii (popeza Sporosarcina pasteurii ili ndi mphamvu yayikulu yopangira urease63). Kuchuluka kwa kuwala kwa yankho la bakiteriya kunali 1.5, ndipo kuchuluka kwa urea ndi calcium chloride kunali 1 M (kusankhidwa kutengera zomwe zidalimbikitsidwa mu maphunziro am'mbuyomu36,64,65). Malo osungiramo zinthu anali ndi msuzi wa michere (8 g/L) ndi urea (20 g/L). Yankho la bakiteriya linapopera pamwamba pa dune ndipo linasiyidwa kwa maola 24 kuti liphatikizidwe ndi bakiteriya. Pambuyo pa maola 24 opakira, yankho lolimbitsa (calcium chloride ndi urea) linapopera. Mayeso owongolera a urealytic MICP amatchedwa UMC. Kuchuluka kwa calcium carbonate mu zitsanzo za nthaka zomwe zinakonzedwa ndi urealytic ndi zomwe sizinakonzedwe ndi urealytic kunapezeka potsuka motsatira njira yomwe Choi et al.66 adapereka.
Chithunzi 5 chikuwonetsa kukula kwa Bacillus amyloliquefaciens ndi Bacillus subtilis mu njira yolerera (njira yopezera michere) yokhala ndi pH yoyambira 5 mpaka 10. Monga momwe chithunzichi chikusonyezera, Bacillus amyloliquefaciens ndi Bacillus subtilis zinakula mofulumira pa pH 6-8 ndi 7-9, motsatana. Chifukwa chake, pH iyi idagwiritsidwa ntchito mu gawo lokonzanso.
Ma curve a kukula kwa (a) Bacillus amyloliquefaciens ndi (b) Bacillus subtilis pa pH yosiyana yoyambirira ya malo osungira michere.
Chithunzi 6 chikuwonetsa kuchuluka kwa carbon dioxide yomwe imapangidwa mu Bernard limemeter, yomwe imayimira calcium carbonate yokhazikika (CaCO3). Popeza chinthu chimodzi chidakhazikika mu kuphatikiza kulikonse ndipo zinthu zina zidasinthasintha, mfundo iliyonse pama graph awa ikugwirizana ndi kuchuluka kwakukulu kwa carbon dioxide mu seti ya zoyesererazo. Monga momwe zasonyezedwera pachithunzichi, pamene kuchuluka kwa calcium source kumawonjezeka, kupanga calcium carbonate kunawonjezeka. Chifukwa chake, kuchuluka kwa calcium source kumakhudza mwachindunji kupanga calcium carbonate. Popeza gwero la calcium ndi gwero la carbon ndi zofanana (mwachitsanzo, calcium formate ndi calcium acetate), ma calcium ions ambiri amatulutsidwa, calcium carbonate yambiri imapangidwa (Chithunzi 6a). Mu AS ndi AA formulations, kupanga calcium carbonate kunapitilira kuwonjezeka ndi nthawi yowonjezera yochiritsa mpaka kuchuluka kwa precipitate kunasintha kwambiri patatha masiku 9. Mu FA formulation, kuchuluka kwa calcium carbonate kunachepa pamene nthawi yochiritsa inapitirira masiku 6. Poyerekeza ndi ma formulations ena, FS formulation inawonetsa kuchuluka kochepa kwa calcium carbonate patatha masiku atatu (Chithunzi 6b). Mu ma formulations FA ndi FS, 70% ndi 87% ya kupanga konse kwa calcium carbonate kunapezeka patatha masiku atatu, pomwe mu ma formulations AA ndi AS, gawoli linali pafupifupi 46% ndi 45% motsatana. Izi zikusonyeza kuti ma formulations ochokera ku formic acid ali ndi kuchuluka kwa CaCO3 komwe kumachitika poyamba poyerekeza ndi ma acetate. Komabe, kuchuluka kwa mapangidwe kumachepa ndi nthawi yowonjezera yochira. Zitha kutsimikiziridwa kuchokera ku Chithunzi 6c kuti ngakhale pa kuchuluka kwa mabakiteriya pamwamba pa OD1, palibe chothandizira chachikulu pakupanga calcium carbonate.
Kusintha kwa kuchuluka kwa CO2 (ndi kuchuluka kwa CaCO3 kofanana) komwe kumayesedwa ndi Bernard calcimeter ngati chifukwa cha (a) kuchuluka kwa calcium source, (b) nthawi yokhazikitsa, (c) OD, (d) pH yoyambirira, (e) chiŵerengero cha calcium source ku bacterial solution (pa mtundu uliwonse); ndi (f) kuchuluka kwakukulu kwa calcium carbonate komwe kumapangidwa pa kuphatikiza kulikonse kwa calcium source ndi mabakiteriya.
Ponena za zotsatira za pH yoyambirira ya medium, Chithunzi 6d chikuwonetsa kuti pa FA ndi FS, kupanga kwa CaCO3 kunafika pamlingo wapamwamba pa pH 7. Izi zikugwirizana ndi kafukufuku wakale kuti ma enzyme a FDH ndi okhazikika kwambiri pa pH 7-6.7. Komabe, pa AA ndi AS, mvula ya CaCO3 inakwera pamene pH inapitirira 7. Kafukufuku wakale adawonetsanso kuti pH yabwino kwambiri ya ntchito ya enzyme ya CoA ndi kuyambira 8 mpaka 9.2-6.8. Poganizira kuti pH yabwino kwambiri ya ntchito ya enzyme ya CoA ndi kukula kwa B. amyloliquefaciens ndi (8-9.2) ndi (6-8), motsatana (Chithunzi 5a), pH yabwino kwambiri ya kapangidwe ka AA ikuyembekezeka kukhala 8, ndipo pH ziwirizi zimaphatikizana. Izi zatsimikiziridwa ndi zoyeserera, monga momwe zasonyezedwera pa Chithunzi 6d. Popeza pH yabwino kwambiri ya kukula kwa B. subtilis ndi 7-9 (Chithunzi 5b) ndipo pH yabwino kwambiri ya ntchito ya enzyme ya CoA ndi 8-9.2, kuchuluka kwa CaCO3 komwe kumaperekedwa kukuyembekezeka kukhala mu pH ya 8-9, zomwe zatsimikiziridwa ndi Chithunzi 6d (mwachitsanzo, pH yabwino kwambiri ya mvula ndi 9). Zotsatira zomwe zawonetsedwa mu Chithunzi 6e zikusonyeza kuti chiŵerengero chabwino kwambiri cha yankho la calcium source ku yankho la bakiteriya ndi 1 pa mayankho onse a acetate ndi formate. Poyerekeza, magwiridwe antchito a mitundu yosiyanasiyana (mwachitsanzo, AA, AS, FA, ndi FS) adayesedwa kutengera kupanga kwakukulu kwa CaCO3 pansi pa mikhalidwe yosiyanasiyana (mwachitsanzo, kuchuluka kwa gwero la calcium, nthawi yochiritsa, OD, chiŵerengero cha yankho la calcium ku yankho la bakiteriya, ndi pH yoyambirira). Pakati pa mitundu yomwe idaphunziridwa, FS yopangidwa inali ndi kupanga kwakukulu kwa CaCO3, komwe kunali pafupifupi katatu kuposa kupanga AA (Chithunzi 6f). Mayeso anayi oletsa mabakiteriya adachitika pa magwero onse a calcium ndipo palibe mvula ya CaCO3 yomwe idawonedwa patatha masiku 30.
Zithunzi za maikulosikopu ya kuwala za mapangidwe onsewa zinasonyeza kuti vaterite inali gawo lalikulu lomwe calcium carbonate inapangidwira (Chithunzi 7). Makristalo a vaterite anali ozungulira 69,70,71. Zinapezeka kuti calcium carbonate inagwera pa maselo a bakiteriya chifukwa pamwamba pa maselo a bakiteriya panalibe mphamvu ndipo imatha kugwira ntchito ngati chokometsera ma cation a divalent. Potengera fomula ya FS monga chitsanzo mu kafukufukuyu, patatha maola 24, calcium carbonate inayamba kupangidwa pa maselo ena a bakiteriya (Chithunzi 7a), ndipo patatha maola 48, chiwerengero cha maselo a bakiteriya okhala ndi calcium carbonate chinawonjezeka kwambiri. Kuphatikiza apo, monga momwe zasonyezedwera mu Chithunzi 7b, tinthu ta vaterite tinapezekanso. Pomaliza, patatha maola 72, mabakiteriya ambiri ankaoneka kuti akugwirizana ndi makristaro a vaterite, ndipo chiwerengero cha tinthu ta vaterite chinawonjezeka kwambiri (Chithunzi 7c).
Kuwona kwa ma microscopy a kuwala kwa CaCO3 mu kapangidwe ka FS pakapita nthawi: (a) 24, (b) 48 ndi (c) maola 72.
Kuti apitirize kufufuza mawonekedwe a gawo lokhazikika, kusanthula kwa X-ray diffraction (XRD) ndi SEM kwa ufa kunachitika. XRD spectra (Chithunzi 8a) ndi SEM micrographs (Chithunzi 8b, c) zinatsimikizira kukhalapo kwa makristalo a vaterite, popeza anali ndi mawonekedwe ofanana ndi letesi ndipo kulumikizana pakati pa nsonga za vaterite ndi nsonga za precipitate kunawonedwa.
(a) Kuyerekeza kwa ma X-ray diffraction spectra a CaCO3 yopangidwa ndi vaterite. Ma SEM micrographs a vaterite pa (b) 1 kHz ndi (c) kukula kwa 5.27 kHz, motsatana.
Zotsatira za mayeso a ngalande ya mphepo zawonetsedwa pa Chithunzi 9a, b. Zitha kuwoneka kuchokera pa Chithunzi 9a kuti liwiro la kukokoloka kwa nthaka (TDV) la mchenga wosakonzedwa ndi pafupifupi 4.32 m/s. Pa mlingo wa 1 l/m² (Chithunzi 9a), malo otsetsereka a mizere ya kutayika kwa nthaka ya magawo FA, FS, AA ndi UMC ndi ofanana ndi a dune wosakonzedwa. Izi zikusonyeza kuti chithandizo pa mlingo uwu wogwiritsidwa ntchito sichigwira ntchito ndipo liwiro la mphepo likangopitirira TDV, kutumphuka kwa nthaka kochepa kumatha ndipo kuchuluka kwa kukokoloka kwa dune kumakhala kofanana ndi kwa dune wosakonzedwa. Malo otsetsereka a AS ndi otsika kuposa a magawo ena okhala ndi abscissas yotsika (monga TDV) (Chithunzi 9a). Mivi yomwe ili pa Chithunzi 9b ikuwonetsa kuti pa liwiro la mphepo la 25 m/s, palibe kukokoloka komwe kunachitika m'madune okonzedwa pa mlingo wa 2 ndi 3 l/m². Mwa kuyankhula kwina, pa FS, FA, AS ndi UMC, milu ya mchenga inali yolimba kwambiri ku kukokoloka kwa mphepo komwe kumachitika chifukwa cha kuikidwa kwa CaCO³ pamlingo wogwiritsidwa ntchito wa 2 ndi 3 l/m² kuposa pa liwiro lalikulu la mphepo (monga 25 m/s). Chifukwa chake, mtengo wa TDV wa 25 m/s womwe wapezeka mu mayeso awa ndi malire otsika a liwiro logwiritsidwa ntchito lomwe lawonetsedwa pa Chithunzi 9b, kupatula pa nkhani ya AA, pomwe TDV ili pafupifupi yofanana ndi liwiro lalikulu la ngalande ya mphepo.
Kuyesa kukokoloka kwa mphepo (a) Kuchepetsa thupi poyerekeza ndi liwiro la mphepo (mlingo wogwiritsa ntchito 1 l/m2), (b) Liwiro lodulira malire poyerekeza ndi liwiro logwiritsa ntchito ndi kapangidwe kake (CA ya calcium acetate, CF ya calcium formate).
Chithunzi 10 chikuwonetsa kuwonongeka kwa pamwamba pa ming'alu ya mchenga yomwe inachiritsidwa ndi mitundu yosiyanasiyana ndi kuchuluka kwa ntchito pambuyo pa mayeso a kuphulika kwa mchenga ndipo zotsatira zake za kuchuluka kwa ntchito zawonetsedwa mu Chithunzi 11. Nkhani yosachiritsidwayo sinawonetsedwe chifukwa sinawonetse kukana ndipo inawonongeka kwathunthu (kutayika konse kwa kulemera) panthawi ya mayeso a kuphulika kwa mchenga. N'zoonekeratu kuchokera ku Chithunzi 11 kuti chitsanzo chomwe chinachiritsidwa ndi biocomposition AA chinataya 83.5% ya kulemera kwake pamlingo wa 2 l/m2 pomwe zitsanzo zina zonse zinawonetsa kuwonongeka kosakwana 30% panthawi ya kuphulika kwa mchenga. Pamene kuchuluka kwa ntchito kunawonjezeka kufika pa 3 l/m2, zitsanzo zonse zomwe zinachiritsidwa zinataya zosakwana 25% ya kulemera kwawo. Pa mlingo wonse wa ntchito, compound FS inasonyeza kukana bwino kwambiri ku kuphulika kwa mchenga. Kukana kwakukulu komanso kochepa kwa kuphulika kwa ntchito mu zitsanzo zomwe zinachiritsidwa ndi FS ndi AA kungatchulidwe chifukwa cha kuchuluka kwawo komanso kochepa kwa CaCO3 (Chithunzi 6f).
Zotsatira za kuphulika kwa ming'alu ya mchenga ya mitundu yosiyanasiyana pamlingo wa 2 ndi 3 l/m2 (mivi imasonyeza komwe mphepo ikupita, mipingo imasonyeza komwe mphepo ikupita molunjika ku ndege ya chojambulacho).
Monga momwe zasonyezedwera pa Chithunzi 12, kuchuluka kwa calcium carbonate m'ma formula onse kunawonjezeka pamene kuchuluka kwa kugwiritsa ntchito kunakwera kuchoka pa 1 L/m² kufika pa 3 L/m². Kuphatikiza apo, pa kuchuluka konse kwa kugwiritsa ntchito, fomula yokhala ndi kuchuluka kwakukulu kwa calcium carbonate inali FS, kutsatiridwa ndi FA ndi UMC. Izi zikusonyeza kuti ma formula awa akhoza kukhala ndi kukana kwakukulu pamwamba.
Chithunzi 13a chikuwonetsa kusintha kwa kukana pamwamba pa zitsanzo za nthaka zosakonzedwa, zowongolera komanso zochiritsidwa zomwe zimayesedwa pogwiritsa ntchito mayeso a permeameter. Kuchokera pachithunzichi, zikuwonekeratu kuti kukana pamwamba pa UMC, AS, FA ndi FS kunawonjezeka kwambiri ndi kuwonjezeka kwa kuchuluka kwa kugwiritsa ntchito. Komabe, kuwonjezeka kwa mphamvu pamwamba kunali kochepa mu kapangidwe ka AA. Monga momwe chithunzichi chikusonyezera, mapangidwe a FA ndi FS a MICP yosawonongeka ndi urea ali ndi kulowerera bwino pamwamba poyerekeza ndi MICP yosawonongeka ndi urea. Chithunzi 13b chikuwonetsa kusintha kwa TDV ndi kukana pamwamba pa nthaka. Kuchokera pachithunzichi, zikuwonekeratu kuti pa ma dunes omwe ali ndi kukana pamwamba kopitilira 100 kPa, liwiro lochotsa malire lidzapitirira 25 m/s. Popeza kukana pamwamba pa situ kumatha kuyezedwa mosavuta ndi permeameter, chidziwitsochi chingathandize kuyerekeza TDV popanda kuyesa kwa ngalande ya mphepo, motero chimagwira ntchito ngati chizindikiro chowongolera khalidwe la ntchito za m'munda.
Zotsatira za SEM zawonetsedwa pa Chithunzi 14. Zithunzi 14a-b zikuwonetsa tinthu tating'onoting'ono ta nthaka yosakonzedwa, zomwe zikusonyeza momveka bwino kuti ndi yogwirizana ndipo ilibe mgwirizano wachilengedwe kapena simenti. Chithunzi 14c chikuwonetsa SEM micrograph ya chitsanzo chowongolera chomwe chathandizidwa ndi urea-degraded MICP. Chithunzichi chikuwonetsa kukhalapo kwa CaCO3 precipitates ngati calcite polymorphs. Monga momwe zasonyezedwera pa Zithunzi 14d-o, CaCO3 precipitated imagwirizanitsa tinthu tating'onoting'ono; makristalo ozungulira a vaterite amathanso kuzindikirika mu SEM micrographs. Zotsatira za kafukufukuyu ndi kafukufuku wakale zikuwonetsa kuti ma CaCO3 bonds opangidwa ngati vaterite polymorphs angaperekenso mphamvu yoyenera yamakina; zotsatira zathu zikuwonetsa kuti kukana kwa pamwamba kumawonjezeka kufika pa 350 kPa ndipo liwiro lopatukana kwa threshold limawonjezeka kuchokera pa 4.32 mpaka kupitirira 25 m/s. Zotsatirazi zikugwirizana ndi zotsatira za kafukufuku wakale kuti matrix ya MICP-precipitated CaCO3 ndi vaterite, yomwe ili ndi mphamvu yoyenera yamakina komanso yolimbana ndi kukokoloka kwa mphepo13,40 ndipo imatha kusunga kukana kokokoloka kwa mphepo ngakhale patatha masiku 180 kuchokera pamene yakhudzidwa ndi nyengo zakumunda13.
(a, b) Ma micrograph a SEM a nthaka yosakonzedwa, (c) Kuwongolera kuwonongeka kwa urea kwa MICP, (df) Zitsanzo zokonzedwa ndi AA, (gi) Zitsanzo zokonzedwa ndi AS, (jl) Zitsanzo zokonzedwa ndi FA, ndi (mo) Zitsanzo zokonzedwa ndi FS pamlingo wa 3 L/m2 pakukula kosiyanasiyana.
Chithunzi 14d-f chikuwonetsa kuti pambuyo pothandizidwa ndi mankhwala a AA, calcium carbonate inagwera pamwamba ndi pakati pa tinthu ta mchenga, pomwe tinthu tina ta mchenga tosaphimbidwa tinawonedwanso. Pazigawo za AS, ngakhale kuchuluka kwa CaCO3 komwe kunapangidwa sikunakwere kwambiri (Chithunzi 6f), kuchuluka kwa kukhudzana pakati pa tinthu ta mchenga komwe kunayambitsidwa ndi CaCO3 kunakwera kwambiri poyerekeza ndi mankhwala a AA (Chithunzi 14g-i).
Kuchokera pa Zithunzi 14j-l ndi 14m-o, n'zoonekeratu kuti kugwiritsa ntchito calcium formate ngati gwero la calcium kumabweretsa kuwonjezeka kwina kwa mvula ya CaCO3 poyerekeza ndi AS compound, zomwe zikugwirizana ndi muyeso wa calcium meter womwe uli mu Chithunzi 6f. CaCO3 yowonjezerayi ikuwoneka kuti imayikidwa makamaka pa tinthu ta mchenga ndipo sizimawonjezera kukhudzana. Izi zikutsimikizira khalidwe lomwe lidawonedwa kale: ngakhale kusiyana kwa kuchuluka kwa mvula ya CaCO3 (Chithunzi 6f), mitundu itatu (AS, FA ndi FS) sisiyana kwambiri pankhani ya magwiridwe antchito a anti-eolian (mphepo) (Chithunzi 11) ndi kukana pamwamba (Chithunzi 13a).
Kuti tiwone bwino maselo a bakiteriya okhala ndi CaCO3 komanso chizindikiro cha bakiteriya pa makhiristo okhuthala, ma micrograph a SEM okulitsa kwambiri adatengedwa ndipo zotsatira zake zikuwonetsedwa mu Chithunzi 15. Monga momwe zasonyezedwera, calcium carbonate imagwera pa maselo a bakiteriya ndipo imapereka ma nuclei ofunikira kuti mvula igwere pamenepo. Chithunzichi chikuwonetsanso kulumikizana kogwira ntchito komanso kosagwira ntchito komwe kumachitika chifukwa cha CaCO3. Titha kunena kuti kuwonjezeka kulikonse kwa kulumikizana kosagwira ntchito sikuti kumabweretsa kusintha kwina mu machitidwe a makina. Chifukwa chake, kuwonjezera mvula ya CaCO3 sikuti kumabweretsa mphamvu yayikulu yamakina ndipo mawonekedwe a mvula amatenga gawo lofunikira. Mfundoyi yaphunziridwanso m'ntchito za Terzis ndi Laloui72 ndi Soghi ndi Al-Kabani45,73. Kuti tifufuze bwino ubale pakati pa mawonekedwe a mvula ndi mphamvu yamakina, maphunziro a MICP pogwiritsa ntchito µCT imaging akulangizidwa, zomwe sizingafanane ndi kafukufukuyu (mwachitsanzo, kuyambitsa kuphatikiza kosiyanasiyana kwa gwero la calcium ndi mabakiteriya kuti MICP yopanda ammonia igwire ntchito).
CaCO3 inayambitsa ma bond ogwira ntchito komanso osagwira ntchito m'zitsanzo zomwe zinapatsidwa (a) kapangidwe ka AS ndi (b) kapangidwe ka FS ndipo inasiya chizindikiro cha maselo a bakiteriya pa dothi.
Monga momwe zasonyezedwera mu Zithunzi 14j-o ndi 15b, pali filimu ya CaCO (malinga ndi kusanthula kwa EDX, kuchuluka kwa chinthu chilichonse mu filimuyi ndi kaboni 11%, mpweya 46.62% ndi calcium 42.39%, zomwe zili pafupi kwambiri ndi kuchuluka kwa CaCO mu Chithunzi 16). Filimuyi imaphimba makristalo a vaterite ndi tinthu ta nthaka, zomwe zimathandiza kusunga umphumphu wa dongosolo la nthaka-sediment. Kupezeka kwa filimuyi kunawonedwa kokha m'zitsanzo zomwe zinathandizidwa ndi formate-based formulation.
Gome 2 likuyerekeza mphamvu ya pamwamba, liwiro la kuchotsedwa kwa nthaka, ndi kuchuluka kwa CaCO3 komwe kumayambitsa matenda m'nthaka zomwe zimathandizidwa ndi njira za MICP zomwe zimawonongeka ndi urea komanso zomwe sizimawonongeka ndi urea m'maphunziro am'mbuyomu komanso kafukufukuyu. Kafukufuku wokhudza kukana kukokoloka kwa nthaka kwa zitsanzo za dune zomwe zimathandizidwa ndi MICP ndizochepa. Meng et al. adafufuza kukana kukokoloka kwa nthaka kwa zitsanzo za dune zomwe zimawonongeka ndi urea zomwe zimathandizidwa ndi MICP pogwiritsa ntchito chowombera masamba,13 pomwe mu kafukufukuyu, zitsanzo za dune zomwe sizimawonongeka ndi urea (komanso zowongolera zowononga urea) zidayesedwa mu ngalande ya mphepo ndikuchiritsidwa ndi mitundu inayi yosiyanasiyana ya mabakiteriya ndi zinthu zina.
Monga momwe taonera, maphunziro ena am'mbuyomu adaganizira za kuchuluka kwa madzi ogwiritsidwa ntchito kuposa 4 L/m213,41,74. Ndikofunikira kudziwa kuti kuchuluka kwa madzi ogwiritsidwa ntchito sikungakhale kosavuta m'munda malinga ndi zachuma chifukwa cha ndalama zomwe zimagwiritsidwa ntchito popereka madzi, mayendedwe ndi kugwiritsa ntchito madzi ambiri. Kutsika kwa madzi ogwiritsidwa ntchito monga 1.62-2 L/m2 kunapezanso mphamvu zabwino pamwamba mpaka 190 kPa ndi TDV yopitirira 25 m/s. Mu kafukufukuyu, milu yomwe inathandizidwa ndi MICP yochokera ku formate popanda kuwonongeka kwa urea inapeza mphamvu zapamwamba pamwamba zomwe zinali zofanana ndi zomwe zinapezeka ndi njira yowonongeka kwa urea mu kuchuluka komweko kwa madzi ogwiritsidwa ntchito (mwachitsanzo, zitsanzo zomwe zinathandizidwa ndi MICP yochokera ku formate popanda kuwonongeka kwa urea zinathanso kupeza mphamvu zofanana pamwamba monga momwe zinanenedwera ndi Meng et al., 13, Chithunzi 13a) pamlingo wapamwamba wogwiritsidwa ntchito. Zitha kuonekanso kuti pa mlingo wa 2 L/m2, phindu la calcium carbonate pochepetsa kukokoloka kwa nthaka ndi mphepo pa liwiro la mphepo la 25 m/s linali 2.25% pa MICP yochokera ku formate yopanda kuwonongeka kwa urea, yomwe ili pafupi kwambiri ndi kuchuluka kwa CaCO3 kofunikira (mwachitsanzo 2.41%) poyerekeza ndi minda yokonzedwa ndi MICP yolamulira yokhala ndi kuwonongeka kwa urea pa mlingo womwewo komanso liwiro la mphepo lomwelo (25 m/s).
Motero, tinganene kuchokera pa tebulo ili kuti njira yonse yowononga urea ndi njira yowononga yopanda urea zingapereke ntchito yovomerezeka pankhani yolimbana ndi pamwamba ndi TDV. Kusiyana kwakukulu ndikuti njira yowononga yopanda urea ilibe ammonia ndipo motero ili ndi zotsatira zochepa pa chilengedwe. Kuphatikiza apo, njira ya MICP yochokera ku formate yopanda kuwonongeka kwa urea yomwe yaperekedwa mu kafukufukuyu ikuwoneka kuti ikugwira ntchito bwino kuposa njira ya MICP yochokera ku acetate yopanda kuwonongeka kwa urea. Ngakhale Mohebbi et al. adaphunzira njira ya MICP yochokera ku acetate popanda kuwonongeka kwa urea, kafukufuku wawo adaphatikizapo zitsanzo pamalo athyathyathya9. Chifukwa cha kuchuluka kwa kuwonongeka komwe kumachitika chifukwa cha kupangika kwa eddy kuzungulira zitsanzo za dune ndi kudulidwa komwe kumachitika, komwe kumabweretsa TDV yotsika, kuwonongeka kwa zitsanzo za dune kukuyembekezeka kukhala kowonekera bwino kuposa malo athyathyathya pa liwiro lomwelo.