Izicishamlilo zisebenzisa i-aqueous Film-forming foam (AFFF) ukusiza ukucisha imililo enzima ukulwa, ikakhulukazi imililo ebandakanya uphethiloli noma olunye uketshezi oluvutha ‚eyaziwa njengemililo yeClass B. Kodwa-ke, akuzona zonke izigaxa ezicisha umlilo ezihlukaniswa njenge-AFFF.

Okunye ukwakheka kwe-AFFF kuqukethe isigaba samakhemikhali esaziwa njenge ama-perfluorochemicals (PFCs) futhi lokhu kuphakamise ukukhathazeka mayelana namandla woku ukungcoliswa kwamanzi angaphansi komhlaba imithombo evela ekusetshenzisweni kwama-ejenti e-AFFF aqukethe ama-PFC.

NgoMeyi 2000, i- Inkampani ye-3M ithe ngeke isakwazi ukukhiqiza i-PFOS (perfluorooctanesulphonate) -based flurosurfactants esebenzisa inqubo ye-electrochemical flouorination. Ngaphambi kwalokhu, ama-PFC ajwayelekile kakhulu asetshenziswa kumagwebu okucisha umlilo kwakuyi-PFOS kanye nokutholakala kwayo.

I-AFFF icisha imililo kaphethiloli ngokushesha, kepha iqukethe i-PFAS, emele izinto ze-per- ne-polyfluoroalkyl. Okunye ukungcoliswa kwePFAS kubangelwa ukusetshenziswa kwamagwebu okulwa nomlilo. (I-Photo / Joint Base San Antonio)

IZIHLOKO EZIHLOBENE

Uma kubhekwa 'okusha okujwayelekile' kwezinto zokusebenza zomlilo

Ukusakaza okunobuthi 'kwe-foam eyimfihlo' eduze kwaseDetroit kwakunguPFAS - kepha kusuka kuphi?

Igwebu lomlilo elisetshenziselwa ukuqeqeshwa eConn. Lingaba nobungozi obukhulu bezempilo, nezemvelo

Eminyakeni embalwa edlule, imboni ye-foam yokulwa nomlilo isukile kude ne-PFOS kanye nezithako zayo ngenxa yengcindezi yezomthetho. Labo bakhiqizi bakhiqize futhi baletha emakethe amagwebu okucisha umlilo angasebenzisi ama-fluorochemicals, okungukuthi, angenayo i-fluorine.

Abenzi bamagwebu angenawo fluorine bathi lezi zigaxa zinomthelela omncane emvelweni futhi zihlangabezana nokuvunyelwa kwamazwe omhlaba ngezidingo zokulwa nomlilo nokulindelwe ngabasebenzisi bokugcina. Noma kunjalo, kuyaqhubeka ukukhathazeka kwemvelo mayelana namagwebu okulwa nomlilo futhi ucwaningo ngale ndaba luyaqhubeka.

UKHATHAZEKA NGOKUSETSHENZISWA KWE-AFFF?

Isikhungo sokukhathazeka sizungeze umthelela ongemuhle ongaba khona emvelweni kusukela ekuchithweni kwezixazululo zegwebu (inhlanganisela yamanzi kanye ne-foam concentrate). Izingqinamba eziyinhloko ubuthi, i-biodegradability, ukuphikelela, ukwelashwa ezitshalweni zokuhlanza amanzi angcolile nokulayishwa kwezakhi zenhlabathi. Konke lokhu kuyimbangela yokukhathazeka lapho izixazululo ze-foam zifinyelela izinhlelo zemvelo noma zasekhaya zamanzi.

Lapho i-AFC equkethe i-AFFF isetshenziswa kaninginingi endaweni eyodwa isikhathi eside, ama-PFC angasuka kugwebu angene enhlabathini bese angena emanzini angaphansi komhlaba. Inani lama-PFC angena emanzini angaphansi komhlaba ancike ohlotsheni nenani le-AFFF esetshenzisiwe, lapho isetshenziswe khona, uhlobo lomhlabathi nezinye izinto.

Uma imithombo yangasese noma yomphakathi itholakala eduze, ingahle ithintwe yi-PFCs kusuka lapho kwakusetshenziswa khona i-AFFF. Nakhu ukubuka ukuthi uMnyango Wezempilo waseMinnesota ushicilele ini; ingesinye sezifundazwe eziningana ukuhlola ukungcoliswa.

“Ngo-2008-2011, iMinnesota Pollution Control Agency (MPCA) yahlola inhlabathi, amanzi angaphezulu, amanzi angaphansi komhlaba, kanye nezidumbu ezindaweni eziseduze nezingu-13 ze-AFFF ezizungeze izwe. Bathola amazinga aphezulu ama-PFC kwezinye zezindawo, kepha ezimweni eziningi ukungcoliswa akuzange kuthinte indawo enkulu noma kubeke engcupheni abantu noma imvelo. Izindawo ezintathu - iDuluth Air National Guard Base, iBemidji Airport, neWestern Area Fire Training Academy - zikhonjwe lapho ama-PFC esabalele khona ngokwanele ukuthi uMnyango Wezempilo waseMinnesota ne-MPCA bathathe isinqumo sokuhlola imithombo yokuhlala eseduze.

“Lokhu kungenzeka kwenzeke eduze nezindawo lapho i-PFC equkethe i-PFFF isetshenziswe kaninginingi, njengezindawo zokuqeqeshela umlilo, izikhumulo zezindiza, izindawo zokuhlanza, nezitshalo zamakhemikhali. Kuncane amathuba okuthi kwenzeke kusukela ekusetshenzisweni kwesikhathi esisodwa kwe-AFFF ukulwa nomlilo, ngaphandle kokuthi kusetshenziswe imiqulu emikhulu ye-AFFF. Yize ezinye izicisha-mlilo ezithwala umlilo zingase zisebenzise i-PFFF equkethe i-PFFF, kodwa ukusetshenziswa kwesilinganiso esincane kangako kungadala ingozi emanzini angaphansi komhlaba. ”

UKUTHOLAKALA KWE-FOAM

Ukukhishwa kwesixazululo se-foam / samanzi kungenzeka kube ngumphumela wesimo esisodwa noma eziningi ezilandelayo:

  • Imisebenzi yokucisha umlilo noma yokuvala uphethiloli;
  • Ukuzivocavoca umzimba lapho kusetshenziswa khona amagwebu kuzimo;
  • Uhlelo lwemishini yama-foam nokuhlolwa kwezimoto; noma
  • Ukukhishwa kwesistimu okungaguquki.

Izindawo lapho kungenzeka khona ukuthi eyodwa noma eminingi yale micimbi ifaka phakathi izakhiwo zezindiza nezindawo zokuqeqesha abacimi bomlilo. Izindawo ezikhethekile ezinobungozi, ezinjengezinqolobane zokugcina izinto ezingasha kalula / ezinobungozi, izindawo zokugcina uketshezi oluvutha kalula nezindawo zokugcina imfucuza enobungozi, nazo ziyalwenza lolu hlu.

Kuyinto efiseleka kakhulu ukuqoqa izixazululo ze-foam ngemuva kokusetshenziswa kwayo kwemisebenzi yokucisha umlilo. Ngaphandle kwengxenye ye-foam uqobo, i-foam kungenzeka ukuthi ingcoliswe ngophethiloli noma ngamafutha abandakanyeka emlilweni. Sekuvele umcimbi ojwayelekile wezinto ezinobungozi.

Amasu okulawula mathupha asetshenziselwa ukuchitheka okubandakanya uketshezi olunobungozi kufanele kusetshenziswe lapho izimo nemvume yokusebenza. Lokhu kufaka phakathi ukuvimba amapayipi esiphepho ukuvimbela isixazululo se-foam / samanzi esingcolile ukuthi singene ohlelweni lwamanzi angcolile noma endaweni engalawulwa.

Amaqhinga okuzivikela njengokudama, ukumisa amanzi nokuchezuka kufanele kusetshenziselwe ukuthola isixazululo segwebu / samanzi endaweni efanelekile ukunakekelwa kuze kube ingasuswa ngusonkontileka wokuhlanza izinto eziyingozi.

UKUQEQESHWA NGENKUNZI

Kukhona amagwebu okuqeqeshwa aklanyelwe ngokukhethekile atholakala kubakhiqizi abaningi bamagwebu abalingisa i-AFFF ngesikhathi sokuqeqeshwa bukhoma, kepha aqukethe ama-flourosurfactants afana ne-PFC. Lezi zigaxa zokuqeqesha zivamise ukubola futhi zinomthelela omncane kwezemvelo; zingathunyelwa futhi ngokuphepha endaweni yokucwenga amanzi angcolile ukuze icutshungulwe.

Ukungabikho kwama-flourosurfactants ekuqeqesheni i-foam kusho ukuthi lezo zigaxa zinokumelana okuncishisiwe kokubuyela emuva. Isibonelo, igwebu lokuqeqesha lizohlinzeka ngesithiyo sokuqala somhwamuko emlilweni oketshezi ovuthayo oholele ekucimeni, kepha leyo ngubo yegwebu izobhidlika ngokushesha.

Lokho kuyinto enhle ngombono womfundisi ngoba kusho ukuthi ungenza ezinye izimo zokuqeqesha ngoba wena nabafundi bakho anilindelanga isimulator yokuqeqeshwa ukuthi isilungele ukusha futhi.

Ukuzivocavoca umzimba, ikakhulukazi labo abasebenzisa amagwebu aqediwe wangempela, kufanele kufaka izinhlinzeko zokuqoqwa kwegwebu elisetshenzisiwe. Okungenani, izindawo zokuqeqesha umlilo kufanele zibe namandla okuqoqa isisombululo se-foam esisetshenziselwa izimo zokuqeqesha ukukhishelwa esikhungweni sokuhlanzwa kwamanzi angcolile.

Ngaphambi kwalokhu kukhishwa, indawo yokuhlanza amanzi angcolile kufanele yaziswe futhi inikezwe umnyango wezomlilo imvume yokuthi umenzeli akhishwe ngezinga elibekiwe.

Impela ukuthuthuka kohlelo lokungeniswa kogwebu lweClass A (futhi mhlawumbe ne-ejenti chemistry) kuzoqhubeka nokuthuthuka njengoba kwenzekile eminyakeni eyishumi edlule. Kepha maqondana nokugxila kwe-foam B Class B, imizamo yokuthuthukisa i-agent chemistry kubonakala sengathi iqandiswe ngesikhathi ngokuthembela kubuchwepheshe obukhona besisekelo.

Kusukela lapho kwethulwe imithethonqubo yezemvelo kule minyaka eyishumi edlule noma kuma-AFFF asuselwa ku-fluorine lapho abakhiqizi begwebu abacisha umlilo bethathe inselelo yentuthuko ngokungathi sína. Eminye yale mikhiqizo engena-fluorine isizukulwane sokuqala kanti eminye isizukulwane sesibili noma sesithathu.

Bazoqhubeka nokuvela kuwo womabili amakhemikhali e-ejenti kanye nasekucimeni umlilo ngenhloso yokufeza ukusebenza okuphezulu kuketshezi oluvuthayo futhi oluvuthayo, ukukhuphula ukumelana nokubuyela emuva kokushiswa kokuphepha kwabacimi bomlilo nokuhlinzeka ngeminyaka eminingi eyengeziwe yempilo eshalofini ngaphezu kwamagwebu atholakala kumaprotheni. 


Isikhathi Iposi: Aug-27-2020