Abacimi-mlilo basebenzisa igwebu leFilimu elenziwe ngamanzi (AFFF) ukunceda ukucima imililo ekunzima ukuyilwa, ngakumbi imililo ebandakanya i-petroleum okanye olunye ulwelo olunokutsha ‚ olwaziwa njengemililo yodidi B. Nangona kunjalo, ayingawo onke amagwebu okucima umlilo ahlelwa njenge-AFFF.

Eminye imixube ye-AFFF iqulethe iklasi yeekhemikhali ezaziwa ngokubaperfluorochemicals (PFCs)kwaye oku kuphakamise inkxalabo malunga nokubanakhoukungcoliseka kwamanzi aphantsi komhlabaimithombo evela kusetyenziso lweearhente ze-AFFF eziqulathe ii-PFCs.

NgoMeyi 2000, iInkampani ye-3Mithe ayisayi kuphinda ivelise iPFOS (perfluorooctanesulphonate)-based flurosurfactants isebenzisa inkqubo ye-electrochemical flouorination. Ngaphambi koku, ii-PFCs eziqhelekileyo ezisetyenziselwa amagwebu okucima umlilo yayiyiPFOS kunye nezinto eziphuma kuyo.

I-AFFF icima ngokukhawuleza imililo yamafutha, kodwa iqulethe i-PFAS, emele izinto ze-per- kunye ne-polyfluoroalkyl. Olunye ungcoliseko lwePFAS luvela ekusetyenzisweni kwamagwebu omlilo. (Ifoto/Isiseko esiDityanisiweyo saseSan Antonio)

AMANQAKU ENXULUMENEYO

Ukuqwalasela 'isiqhelo esitsha' sezixhobo zomlilo

Umjelo onetyhefu 'wegwebu eliyimfihlakalo' kufutshane neDetroit yayiyiPFAS - kodwa ivela phi?

I-foam yomlilo esetyenziselwa uqeqesho kwi-Conn ingabangela impilo enzima, ingozi yendalo

Kwiminyaka embalwa edlulileyo, imboni ye-foam yokucima umlilo iye yasuka kwi-PFOS kunye nezinto eziphuma kuyo ngenxa yoxinzelelo lomthetho. Abo bavelisi baye baphuhlisa kwaye bazisa ukuthengisa amagwebu okucima umlilo angasebenzisi i-fluorochemicals, oko kukuthi, i-fluorine-free.

Abavelisi be-fluorine-free foams bathi la magwebu anempembelelo encinci kwindalo kwaye ahlangabezane nemvume yamazwe ngamazwe kwiimfuno zokucima umlilo kunye nokulindela komsebenzisi wokugqibela. Nangona kunjalo, kukho inkxalabo yokusingqongileyo malunga namagwebu omlilo kunye nophando malunga nalo mbandela uyaqhubeka.

INGXAPHO NGOKUSETYENZISWA KWE-AFFF?

Iinkxalabo ziphakathi kwefuthe elibi elinokubakho kokusingqongileyo ukusuka ekukhutshelweni kwezisombululo zogwebu (indibaniselwano yamanzi kunye nokugxila kogwebu). Imiba ephambili yityhefu, ukonakaliswa kwezinto eziphilayo, ukuzingisa, ukunyangeka kwizityalo zokucocwa kwamanzi amdaka kunye nokulayishwa kwezondlo zomhlaba. Zonke ezi zibangela inkxalabo xa izisombululo ze-foam zifikelelaiinkqubo zamanzi endalo okanye asekhaya.

Xa i-PFC equlethe i-AFFF isetyenziswa ngokuphindaphindiweyo kwindawo enye ixesha elide, ii-PFCs zinokusuka kwi-foam ziye emhlabeni zize zibe kumanzi aphantsi komhlaba. Ubungakanani be-PFCs abangena kumanzi aphantsi komhlaba buxhomekeke kuhlobo kunye nobungakanani be-AFFF esetyenzisiweyo, apho yayisetyenziswe khona, uhlobo lomhlaba kunye nezinye izinto.

Ukuba amaqula abucala okanye kawonke-wonke abekwe kufutshane, anokuchaphazeleka zii-PFCs kwindawo apho i-AFFF yayisetyenziswa khona. Nantsi ukujonga into epapashwe kwiSebe lezeMpilo laseMinnesota; lelinye lamazwe amaninziuvavanyo losulelo.

Ngo-2008-2011, i-Arhente yoLawulo loNgcoliseko yaseMinnesota (MPCA) yavavanya umhlaba, amanzi angaphezulu, amanzi aphantsi komhlaba, kunye nentlenga kwiindawo ezikufutshane ne-13 ze-AFFF ezijikeleze urhulumente. Bafumene amanqanaba aphezulu e-PFC kwezinye iindawo, kodwa kwiimeko ezininzi ungcoliseko aluzange luchaphazele indawo enkulu okanye lubeke umngcipheko ebantwini okanye kwindalo esingqongileyo. Iziza ezintathu - i-Duluth Air National Guard Base, i-Airport yaseBemidji, kunye ne-Western Area Fire Training Academy - zichongiwe apho i-PFCs yayisasazeke ngokwaneleyo ukuba iSebe lezeMpilo laseMinnesota kunye ne-MPCA ligqibe ukuvavanya amaqula akufutshane okuhlala.

"Oku kunokwenzeka ukuba kwenzeke kufutshane neendawo apho i-PFC equlethe i-AFFF isetyenziswe ngokuphindaphindiweyo, njengendawo yokuqeqesha umlilo, izikhululo zeenqwelo moya, iindawo zokucoca kunye nezityalo zemichiza. Akunakwenzeka ukuba kwenzeke ngokusetyenziswa kwexesha elinye kwe-AFFF ukulwa umlilo, ngaphandle kokuba kusetyenziswe umthamo omkhulu we-AFFF. Nangona ezinye izicima-mlilo eziphathwayo zinokusebenzisa i-PFC-equlathe i-AFFF, ngaxeshanye ukusetyenziswa kwesi sixa sincinci akunakufane kubangele ingozi kumanzi aphantsi komhlaba.”

UKUKHUPHA UBUgwebu

Ukukhutshwa kogwebu/isisombululo samanzi kunokuba sisiphumo semeko enye okanye ngaphezulu kwezi zilandelayo:

• Ukucima umlilo ngesandla okanye imisebenzi yokugubungela amafutha;
• Uqeqesho loqeqesho apho kusetyenziswa ugwebu kwiimeko;
• Inkqubo yezixhobo zogwebu kunye novavanyo lwesithuthi; okanye
• Ukukhutshwa kwenkqubo esisigxina.

Iindawo apho isiganeko esinye okanye ezininzi ezinokuthi zenzeke zibandakanya izixhobo zenqwelomoya kunye nezibonelelo zoqeqesho lwabacimi-mlilo. Izibonelelo ezikhethekileyo zengozi, ezifana neendawo zokugcina izinto ezinokutsha/ eziyingozi, izibonelelo ezininzi zokugcina ulwelo olunokutsha kunye neendawo zokugcina inkunkuma eyingozi, nazo zenza uluhlu.

Kunqweneleka kakhulu ukuqokelela izisombululo zegwebu emva kokusetyenziswa kwayo kwimisebenzi yokucima umlilo. Ngaphandle kwecandelo logwebu ngokwalo, ugwebu lunongcoliseka ngamafutha okanye amafutha abandakanyeka emlilweni. Kuqhambuke umsitho oqhelekileyo wezinto ezinobungozi.

Iindlela zokuzibamba ngesandla ezisetyenziselwa ukuchitheka okubandakanya ulwelo oluyingozi kufuneka zisetyenziswe xa iimeko kunye nabasebenzi bevuma. Oku kubandakanya ukuthintela imijelo yemvula ukuthintela ugwebu/isisombululo samanzi esingcolisekileyo ukuba singene kwinkqubo yamanzi amdaka okanye indawo engqongileyo ingaqwalaselwanga.

Amaqhinga okuzikhusela anjengokudama, ukuntywila kunye nokuphambukisa kufuneka asetyenziswe ukufumana ugwebu/isisombululo samanzi kwindawo elungele ukuvalelwa de ibenokususwa yikontraka yokucoca izinto eziyingozi.

UQEQESHO NGOBUgwebu

Kukho amagwebu oqeqesho ayilwe ngokukodwa afumanekayo kuninzi lwabavelisi begwebu abalingisa i-AFFF ngexesha loqeqesho oluphilayo, kodwa aluqulathanga i-flourfactants efana ne-PFC. La magwebu oqeqesho aqhele ukubola kwaye anempembelelo encinci yokusingqongileyo; zinokuthunyelwa ngokukhuselekileyo kwindawo yokucocwa kwamanzi amdaka engingqi ukuze zilungiswe.

Ukungabikho kwe-flourfactants ekuqeqesheni ugwebu kuthetha ukuba loo magwebu anokuncipha kokumelana nokutshisa. Ngokomzekelo, i-foam yoqeqesho iya kubonelela ngesithintelo sokuqala somphunga kumlilo ovuthayo ovuthayo obangela ukucima, kodwa loo ngubo ye-foam iya kuphuka ngokukhawuleza.

Yinto entle leyo ngokwembono yomqeqeshi njengoko kuthetha ukuba ungaqhuba iimeko zoqeqesho ngakumbi kuba wena nabafundi bakho anilindi ukuba isilingisi soqeqesho sitshise silungile kwakhona.

Ukuziqhelanisa noqeqesho, ngakumbi abo basebenzisa amagwebu okwenene agqityiweyo, kufuneka babandakanye izibonelelo zokuqokelela amagwebu asetyenzisiweyo. Ubuncinci, izibonelelo zoqeqesho lomlilo kufuneka zibe namandla okuqokelela isisombululo se-foam esisetyenziswe kwiimeko zoqeqesho zokukhutshwa kwindawo yokucoca amanzi amdaka.

Ngaphambi kokukhutshwa, indawo yokucoca amanzi amdaka kufuneka yaziswe kwaye imvume inikwe isebe lomlilo ukuze i-arhente ikhutshwe kwizinga elimiselweyo.

Ngokuqinisekileyo uphuhliso kwiinkqubo zokungeniswa kwe-foam yeKlasi A (kwaye mhlawumbi i-agent chemistry) iya kuqhubeka nokuqhubela phambili njengoko idlulileyo kwiminyaka elishumi edlulileyo. Kodwa ngokubhekisele kwi-foam yeKlasi B, iinzame zophuhliso lwekhemistri zibonakala ngathi zikhenkxiwe kwangexesha ngokuthembela kubuchwephesha obukhoyo.

Kuphela ukususela ekuqalisweni kwemithetho yokusingqongileyo kwiminyaka elishumi edlulileyo okanye njalo kwii-AFFF ezisekelwe kwi-fluorine abenzi be-foam bokucima umlilo bawuthathele ingqalelo umngeni wophuhliso. Ezinye zezi mveliso zingenayo i-fluorine zisizukulwana sokuqala kwaye ezinye isizukulwana sesibini okanye sesithathu.

Baya kuqhubeka nokuguquka kwimichiza ye-agent ye-agent kunye nokusebenza komlilo ngenjongo yokufezekisa ukusebenza okuphezulu kumanzi anokutsha kunye nokutsha, ukuchasana okuphuculweyo kokutshisa ukhuseleko lwabacimi-mlilo kunye nokubonelela iminyaka emininzi eyongezelelweyo yobomi beshelufu phezu kwamagwebu aphuma kwiprotheni.