Cov lim dej yog ib qho tseem ceeb ntawm lub tsev cog khoom irrigation systems. Lub luag haujlwm tseem ceeb ntawm cov lim dej yog cais cov khoom tshem tawm lossis yaj tawm ntawm cov dej. Hauv kev siv dej, cov ntxaij lim dej txhawm rau tshem tawm cov khoom uas cuam tshuam rau cov nroj tsuag kev noj qab haus huv lossis kev ua tau zoo thiab kev sib luag ntawm cov dej faib.
Txawm hais tias txhua qhov kev siv dej yuav tsum muaj ntau theem thiab hom lim dej, nws tseem ceeb heev uas yuav tau xaiv cov lim kom raug. Cov neeg cog qoob loo yuav tsum xaiv cov lim dej raws li qhov teeb meem ntawm lub hom phiaj, kev sib raug zoo nrog cov txheej txheem dej tsim, thiab cov nqi pom.
Hom teeb meem thiab kev xaiv pom
Ntawm no yog saib cov dej paug uas muaj nyob hauv tsev cog khoom thiab cov lim dej pom zoo kom tshem tawm cov kab mob no.
Organic hais muaj xws li khib nyiab, algae, thiab cov kab mob. Feem ntau cov kab mob me me (piv txwv li, cov kab mob kis tau tsawg dua 1 μm thiab qee cov kab mob fungal me ntsis qis dua 200 μm) thiab ntes lawv nrog lub lim yuav xav tau qhov pore me me, xws li ultra-fine membrane filtration. Txawm li cas los xij, kev lim dej membrane tsis tshua siv rau daim ntawv thov no vim tias kev nqis peev peev thiab kev ua haujlwm siab yuav tsum tau them nqi.
Cov kws tshawb fawb ntawm University of California thiab Michigan State University tau sim qeeb thiab ceev cov xuab zeb lim kom tshem tawm Phytophthora sp. thiab Nab hab sej sp. thiab tau soj ntsuam cov txiaj ntsig zoo. Cov lim dej no tshem tawm cov kab mob, feem ntau yuav yog los ntawm kev sib xyaw ntawm lub cev thiab cov txheej txheem lom neeg. Cov xuab zeb qeeb qeeb tsim cov txheej txheem biofilm (lub npe hu ua schmutzdecke) uas txo lossis cuam tshuam cov kab mob los ntawm kev cuam tshuam lub cev thiab cov txheej txheem tswj kev lom neeg. Txawm li cas los xij, cov ntxaij lim dej tawm tuaj yeem txhaws yog tias cov khib nyiab hnyav dhau (xws li cov nroj tsuag). Yog li ntawd, ib co coarse pre-filter yog pom zoo. Cov ntxaij lim dej thiab xov xwm tawm tau zoo hauv kev tshem tawm cov khib nyiab loj thiab cov nroj tsuag; lawv tuaj nyob rau hauv ntau qhov ntau thiab tsawg thiab kuj pheej yig.
Inorganic hais los yog khib nyiab muaj xws li cov ntxhia pob zeb zoo li xuab zeb, av nplaum, thiab silt. Cov kab mob no tuaj yeem raug tshem tawm nrog daim ntawv, thom khwm, npo, lossis disc lim. Cov thom khwm cov lim dej tshem tawm cov khoom tsis zoo hauv lub cev zoo heev. Txawm li cas los xij, lawv muaj thaj chaw me me thiab yog li clog yooj yim. Cov thom khwm lim tau pom zoo raws li theem kawg ntawm kev pom. Tsis txhob siv daim nyias nyias kom tshem tawm cov khoom tsis zoo lossis cov khib nyiab pov tseg. Cov kab mob no tuaj yeem ua rau lub cev puas tsuaj.
Dissolved inorganics suav nrog cov ntsev yaj uas feem ntau teev rau ntawm koj qhov kev ntsuam xyuas dej (piv txwv li: hlau, carbonates, calcium, sodium, thiab lwm yam). Membrane filtration yog pom zoo kom tshem tawm cov ntsev yaj los ntawm dej. Rov qab osmosis yuav tshem tawm tag nrho cov ions tsuas yog boron los ntawm dej. Hlau thiab manganese kuj tseem tuaj yeem raug tshem tawm los ntawm kev sib xyaw ua ke ntawm oxidation (chlorine lossis permanganate), tom qab ntawd los ntawm kev pom nrog cov lim dej (piv txwv li, zaub ntsuab).
Dissolved organics muaj xws li agrochemicals thiab humic acids. Granular activated carbon filtration tshem tawm ntau cov tshuaj agrochemicals los ntawm dej. Cov kws tshawb fawb ntawm University of Florida tau pom tias granular activated carbon tau zoo ntawm kev tshem tawm ntau yam tshuaj, suav nrog tshuaj tua kab (acephate, bifenthrin, chlorpyrifos, thiab imidacloprid), tshuaj tua kab mob (glyphosate thiab triclopyr), cog kev loj hlob regulators (flurprimidol, paclobutrazol), thiab thiab cov tshuaj ntxuav dej (quaternary ammonium chloride, sodium hypochlorite, thiab peroxygen). Granular activated carbon filters raug pom zoo thaum siv cov dej los yog cov kav dej uas muaj cov khoom siv ua liaj ua teb - cov pas dej hauv pas dej, cov dej rov ua dua tshiab, lossis cov dej hauv dej.
Cov kev xav tseem ceeb txog kev pom hauv tsev cog khoom irrigation systems
Txhim kho ntau theem ntawm kev pom - los ntawm ntxhib mus rau qhov zoo - kom tsis txhob txhaws ntawm lub cev thiab ua kom muaj txiaj ntsig ntawm kev tshem tawm cov khoom. Tsis tas li, xav txog tus nqi. Piv txwv li, cov ntxaij lim dej hlau hlau tsis tshua muaj nqi thiab tuaj yeem siv los tshem tawm cov lus ntxhib. Fiber filters (daim ntawv los yog thom khwm) yog me ntsis kim dua li cov ntxaij lim dej, thiab lawv feem ntau yog siv los ua qhov kawg pom theem. Ib txwm lim koj cov dej kom zoo ua ntej siv cov lim dej membrane; tsis ua li ntawd yuav ua rau cov tawv nqaij kim.
Khaws cov lim. Ntxuav cov lim tsis tu ncua kom tsis txhob txhaws lossis tawg cov lim. Xaiv cov lim dej tsis siv neeg rov qab ntxuav thaum lim cov organic thiab inorganic khib nyiab.
