Pond Bio Lim
Aquaculture yog kev ua liaj ua teb ntawm cov kab mob hauv dej xws li ntses, crustaceans, molluscs thiab cov nroj tsuag dej, qhov kev thov thoob ntiaj teb rau cov ntses tau muab lub zog rau kev loj hlob sai hauv aquaculture. Hauv xyoo 2012, muaj 66.6 lab tons ntawm cov ntses tsim los ntawm aquaculture, uas suav txog 42.2% ntawm lub ntiaj teb cov khoom noj ntses. Tsis tas li ntawd, aquaculture yog ib qho kev loj hlob sai tshaj plaws ntawm cov khoom noj khoom haus, nrog rau qhov nruab nrab ntawm 6.5% kev loj hlob nyob rau lub sij hawm ntawm 2000 txog 2012.
Aquaculture systems tuaj yeem muab faib ua peb pawg tseem ceeb: qhov dav, ib nrab siv zog thiab hnyav, raws li kev tsim khoom ib chav tsev ntim (m 3) lossis chav tsev (m 2). Lub pas dej me me poob hauv cov kab ke dav dav, lub pas dej kab lis kev cai nrog kev pub mis lossis aeration nyob rau hauv semiintensive, thiab recirculating aquaculture systems yog intensive.
Recirculating aquaculture systems (RAS) yog lub tank-raws li cov txheej txheem uas ib puag ncig tsis tswj tau tag nrho, yog li cov ntses tuaj yeem khaws cia ntawm qhov ntom ntom. RAS thev naus laus zis tau tsim thiab ua kom zoo rau peb lub xyoo dhau los. RAS thev naus laus zis muaj peev xwm ua haujlwm ntawm lub peev xwm siab nrog dej tsawg thiab yog qhov yuav tsum tau ua piv nrog rau kev ua liaj ua teb ntses, kuj RAS tuaj yeem txo cov tshuaj thiab tshuaj tua kab mob thiab pov tseg pov tseg; Tsis tas li ntawd, RAS yog hom-adaptable, uas txhais tau hais tias ntses tuaj yeem tsim tau txhua xyoo. Txawm li cas los xij, RAS xav tau cov peev nyiaj siab thiab kev nqis peev ua haujlwm uas yog qhov tseem ceeb demerit. Ntxiv mus, nws yog ib tug complex system rau startup thiab kev txawj ntse yog xav tau los tswj thiab saib xyuas.
Kev tswj dej zoo hauv RAS yog ua tiav los ntawm ntau yam sib txawv. Feem ntau, RAS muaj lub tshuab cua sov lossis cov khoom siv hluav taws xob los kho cov dej kub, lub tshuab aeration kom txo cov yaj CO 2 concentration, oxygenation system muab cov pa oxygen txaus, lub nruas lim kom tshem tawm cov khib nyiab tshem tawm, cov kab mob tua kab mob (UV thiab ozone khoom) kom tsis txhob muaj kab mob. thiab biofilter system kom tshem tawm cov khib nyiab nitrogen. Alkalinity nyob rau hauv lub system yog tswj los ntawm kev ntxiv tshuaj rau nws.
Muaj ntau hom biofilm siv rau kev kho dej, xws li trickling biofilters, rotating biological contactors (RBC), granular media biofilters, floating hlaws biofilters thiab fluidized txaj biofilters, txhua yam muaj qhov zoo thiab qhov tsis zoo. Lub tshuab lim dej tsis muaj qhov ntim tau zoo; mechanical failures feem ntau tau ntsib nyob rau hauv rotating biological contactors; granular media biofilters xav tau ib ntus rov qab flashing thiab lub txaj fluidized reactors qhia hydraulic instability. Hauv cov ntsiab lus no, lub tshuab txav txaj biofilm reactor (MBBR) tau tsim nyob rau xyoo 1980s thiab thaum ntxov 1990s hauv Norway.
Tam sim no MBBR tau siv thoob ntiaj teb rau kev kho cov dej khib nyiab hauv nroog thiab kev lag luam, nrog rau kev kho dej hauv dej hiav txwv. Hauv kev lag luam aquaculture, MBBR feem ntau yog siv rau nitrification, nrog rau kev tshem tawm cov organic teeb meem. Txhawm rau kom tsis txhob muaj cov kab mob heterotrophic uas haus cov organic teeb meem suppressing cov kab mob nitrifying ntawm cov organic loads siab, MBBR yog ib txwm ua haujlwm ntawm cov organic loads tsawg inan aquaculture system.
Piv nrog rau feem ntau lwm cov biofilm reactors, MBBR siv tag nrho lub tank ntim rau biomass kev loj hlob, nws kuj muaj ib tug tsis tseem ceeb lub taub hau-poob thiab tsis xav tau rau lub sij hawm rov qab ntxuav thiab tsis raug rau clogging. Tsis tas li ntawd, qhov filling feem ntawm biofilm nqa hauv lub reactor tuaj yeem raug nyiam. Txawm li cas los xij, nws raug pom zoo tias sau cov seem yuav tsum tsawg dua 70% kom cov cab kuj raug tshem tawm dawb hauv lub reactor.
MBBR yog ib qho kev siv thev naus laus zis raws li kev tshawb xav biofilm, nrog rau cov khoom siv biofilm loj hlob ntawm cov khoom siv tshwj xeeb uas tsim los ntawm cov yas yas (lossis biomedia) uas raug tshem tawm hauv lub reactor. Nws tuaj yeem ua haujlwm ob qho tib si hauv aerobic thiab anaerobic mob, biomedia tau khaws cia los ntawm kev ntxhov siab los ntawm aeration diffusers, thaum nyob rau hauv cov xwm txheej anaerobic, lub tov khoom yog siv los ua kom biomedia txav. Bio-medias yog tsim los ntawm cov khoom sib txawv thiab cov polyethylene high-density feem ntau yog siv, uas muaj qhov ntom ntom ntawm 0.95g/cm 3. Txhawm rau muab qhov siab tshaj plaws ntawm thaj chaw tshwj xeeb (m 2 / m 3), bio-medias yog tsim los ntawm ntau yam duab thiab ntau thiab tsawg.