TAP CHI HOA HOC T. 50(6)751-755 THANG 12 NAM 2012
BUOC D A U U'NG DUNG HE DO DA KENH TRONG CONG NGHE XO LY NUOC THAI V A NUOI CA L 6 N G
Le Qu6c Hiing', Pham Thj Hai \in\ Vu Phiic Hoang', Pham Thu Giang', Vu Thj Thu Ha', Phgm Hong Phong', Nguyen Hoang Anh', Le Quoc Long' vk Le Minh Thanh^
' Viin Hda hgc. Vien Khoa hgc vd Cdng ngh? Viit Nam
^ Trudng Dgi hgc Thuy lgi, Hd Ngi D^n Tda sogn 11-7-2012 Abstract
Multichanel polenliostat, which can work simuhaneously and continously with 16 sensors is fabricated in Laboratory of Informatics in Chemical Research. Combined with home-made sensors, the system was run lest in the lab as well as in the field. Software created in house was used to measure; conlrol and store data of the dissolved oxygen (DO) in the environment. Equipment tests were conducted at wastewater treatment plant in Nam Sach Indistrial Zone and fish farm in Long An province. Obtained data showed that the equipment is applicable for environmental monitoring, specially in the field of industrial waste water treatment,
Kej'works: Dissolved oxygen, wastewater treatment, environmental monitoring.
l.MdDAU
Nong dp oxi hoa tan (Dissolved Oxygen - DO) la mgt chi tieu het sirc quan trpng ddi vdi moi trudng nudc cung nhu trong cac qua Irinh trong cong nghg sinh hpc nhu len men Irong be phan img sinh hpc, nuoi trong thuy san (tom ca...), be xir Iy moi trudng bang cac qua trinh khac nhau (hieu khi, yem khi...).
Oxi duy tri qua trinh trao doi chat, sinh ra nang lugng cho su sinh trudng, sinh san va tai tao. Do la mgt chi tieu de danh gia chat lugng nudc, va cung la thudc do mire dp d nhiem cac chat huru ca co the phan hiiy sinh hgc (BOD).
DO la k^l qua ciia sg can bang dpng giua ngu6n oxi cung d p tir khong khi do qua Irinh sue khi, khuich tan, sinh ra trong qua trinh quang hgp va lugng oxi mat di do cac qua trinh sinh hoa khac nhau: ho hap, phan buy cac hgp chat hCru co, cac phan ung vdi cac hoa chat khac nhau. Gia trj DO se rat khac nhau tuy Iheo vj tri va thdi gian do do, vigc do dac, dieu chinh d6ng thdi va lien tuc cac gia tri cuan6 tir nhieu dign c^rc oxi la rat quan trgng va cSp thi§t. Tren lh6 gidi, co cac he do tuong tg diing trong cac nha may xd ly nudc thai sinh hgc. Tuy nhien, viSc nhap ngogi mpt hg thdng nhu vay la rat dat tiln va se kho khan trong van dg van hanh va bao dudng.
Vi vay vi§c nghien curu ehl tgo mpt h$ thi6t bj do DO da kenh di6u khiln bang may vi tinh va phin mem thich hgp vdi timg diSu kign cy the cua cac nha may xii ly nudc thai cung nhu quan trie moi trudng nude la can thiet.
Bai bao trinh bay ket qua khao sat ban dau dien bien DO tgi 8-16 vj tri khac nhau trong cong nghg
nuoi ca long va xir ly nudc thai, tren eg sd cac cam bien oxi va thiet bi da kenh tu che tgo.
2.THUCNGHI$M 2.L Cam bien oxi
Vdi muc dich che tgo thiel bi da kenh va cam bien oxi de do dac va dieu khien ham lugng DO trong cac be xir Iy nudc thai va thir nghiem thuc te tai CO sd nuoi ca long. Sa do cau true ciia cam bien oxi kieu Clark dugc neu tren hinh 1 [1].
Khi ap mpt dign the thich hgp vao hai cue cua cam bien Ihi phan ung khir oxi xay ra Iren catot. Oxi khuech tan tir ngoai khong khi vao Irong dung djch va sau do khuech tan tiep tir dung djch den dign cue Iam viec va Iham gia phan img dign hoa.
Trong dieu kien khuech tan gidi han, nong dp oxi tren be mgt ca tot se bang 0, dong dien ty lg thugn vdi lugng oxi khuech tan qua m^ng va dugc mo ta theo phuang Irinh Pick [I]:
Trong do:
i: dong dign k: hang so
D: hg so khuech tan cua oxi qua mang a: dg hoa tan ciia oxi tren mang A: dign lich dign cgc cat6t
Co2- Nong dp oxi hoa tan trong dung dich X: be day cua mang.
TCHH.T. 50(6), 2012
Vi vay sau khi can chuan, tir gia trj ddng dign do dugc dl dang tinh dugc C02.
Nguon dign
GioSng cao su
Dign cue Pt
Hinh I: So do cau lao ciia cam biin oxi kiiu Clark
2.2. Che tao thiet bj do oxi hoa tan da kenh May do DO iam vigc theo nguyen Iy potensioslat (khong che the hai dien cue). Nhu da trinh bay Irong phan nguyen ly lam viec ciia cam bien oxi, dong dien sinh ra ty lg thuan vdi lugng DO khuech Ian qua mang Iham thau oxi. Vi vay, khi do dong dien, co the biet dugc DO trong mau do.
De ch^ tgo may do DO da kenh (16 dien cue do DO hoac nhieu hem), tat ca cac dien cue doi (anot) lam bang bac dugc ndi vdi nguon dien ap 0,65-0,70 V. Khi do dong dien sinh ra ty Ie thuan vdi DO trong mau do dugc chuyen thanh dign ap nhd bg chi^t ap dien trd R. Dien ap nay E = I.R sau khi qua bp chuyen kenh (Mulliflexer 4051) dugc khuich dai Ien lir 10-100 Ian nhd hai tang khuech dai bdi mpt hoac hai bp khuech dgi thuat loan va dugc dpc vao may tinh bdi bp chuyen doi luong tu - so (Analog- Digital-Con verier ADC 12 byte) va dilu khien so tir bg Labjack U3 HV (My).
Phdn mem do
Phkn mem dugc viet phii hgp vdi thiet bj da kenh ten MultiDO.OI, cho phi^p ngudi do Ihay doi cac thong so do khi kich chupt vao 6 Parameter ircn giao dign khi md chuang Irinh, Iga chpn s6 cac kenh do, thdi gian do, gia tri dign thi ap vao...). Sau khi cac thong sd dugc lua chpn, ngudi su dung nhan RUN dl chgy chuang trinh. Gia Irj do dugc tg dgng luu giif dudi dgng bang bilu, d6 thj ....
3. KET QUA VA THAO LUAN
Cac cam biln oxi tg che lao da dugc chgy Ihu trong phong thi nghigm. Cac tinh chSt co ban ciia
Le Quoc Hitng vd cgng stf cam biln dl dugc khdo sat nhu thdi gian dap img, d$
nhgy, dO 6n djnh, dO 15p lgi ... [2-4]. Dong thdi khi nang iam vi§c cOa chiing ciing dugc thu- nghigm song song vdi cac san phdm tuong duang nhgp ngogi. cac ket qua thu dugc khi sir d\ing cam bien tgc ehl tgo kit noi vdi may do dugc trinh bay dudi
3.L K^t qua do DO trong phdng thi nghiam Vi^c chgy thir trong phdng thi nghigm dugc tien hanh lien tyc, tg dpng. Sau khi can chuln cam biln va thiet bi (hinh 2), hg thong ty dpng do, luu giit so ligu. cac ket qua do dugc hien thi dudi dgng do thj, bieu dien bien thien ciia ham lugng oxi do dugc theo thdi gian do trong cac mdi trudng khac nhau.
mm
Htnh 2: He thong do DO da kenh lam viec trong phong thi nghigm
Hinh 3 chi ra rang, cac cam bien khi dat trong ciing mpt khoang do khi dat trong dung djch va ngoai khong khi bao hoa, ca 16 kenh deu cho tin higu luong doi dong nhat. Dieu nay cho thay kha nang Iam vigc ciia cac cam bien che tao dugc la dong deu, cho tin higu thdng nhat. Tren hinh 3b, a nhirng thdi gian do dau tien, cac tin higu do bieu diln d tren la trong ciing mgt binh do, cac gia Irj thu dugc cho ca 16 kenh la nhu nhau. Khi tach cac cam biln ra cac khoang do khac nhau (tir 14:05:00), kit qua thu dirge khac nhau vl gia tri DO. Kit qua luang ty neu tren hinh 3c.
Tir kel qua khao sat Irong phong thi nghigm ve kha nang lam vigc ciia cam bien va thiet bj da k£nh, he thong dugc sii dyng At do DO tai hign trudng 3.2. Ket qua do DO ngoai hign trudng
Hai dja dilm chinh dugc su dung de chgy thir thiet bi ngoai hign trudng la khu xii ly nudc thai Nam Sach, Hai Duong. Khu xd ly nay thu gom toan bg nudc thai san xuat va nudc thai sinh hogt c^a khu do thi mdi Nam Sach va xii ly dl dgt tieu chuan t6i thiiu muc nudc C trudc khi xa ra h§ thong du&ng
TCHH, T. 50(6), 2012 Btrac diu ungdmgh^da...
nudc thai chung ciia khu cong nghiep, sau do khu 6ng be tong vcri cong suit 3.600 m'/ngay c6ng nghi?p s8 tiep tuc xCr ly dat tieu chuan Cic ket qu4 thir nghi?m thiet bi va cam biSn ox miic B truac khi xa ra s6ng Ben Gach theo duimg Iji khu Nam Sach trinh bky tren hinh 4.
(a) s6 li?u thu ngay 28-29 thang 5 nim 2012
S ! S
I i i ; . : i'„ ; ii. : ii. ; ii: ...
(b) so ligu Ihu ngay 30 Ihang 5 nam 2012
(c) so lieu thu ngay I, 4, 5 thang 6 nam 2012
Hinh 3: Bien thien ciia DO theo thdi gian do tai cac moi Irudng khac nhau tren 16 kenh rieng biet
(a) tai be sue khi, ket qua do ngay 15/5/2012
(b) tai be lang va be biin (dudng den dudi ciing), kel qua do ngay 15/5/2012
t : a R f i ! a 8 ! f i 8 i S | i i S S f f i S 9 l 8 :
- OIO — 013 <
(c) bl sue khf, kit qua do ngay 16/5/2012
• OIO • 013 ' 0 1 5
(d) be lang va be biin (dudng den dudi ciing), ket qua do ngay 16/5/2012 Hinh 4: Biln thien DO do dugc Igi Nha may xir ly nudc thai khu Nam Sach, Hai Duong
TCHH.T. 50(6), 2012
Cac ket qua neu tren hinh 4 (a-d) chi ra sy khac bigt vl DO Irong cac bl khao sat, tgi bl syc khi, ham lugng DO cao hon dang kl so vdi DO trong hai be lang va bl bim tuang img. Gia trj DO do dugc Irong be biin la nh6 nhat, chi gan I mg/L. Ket qua chi ra rang thilt bj va cac cam bien lam vigc 6n djnh ngoai hign Irudng, trong cac dieu kign mdi trudng khac nghigt khac nhau.
Hinh 5 (a-d) trinh bay ket qua thu nghigm ngoai
Le Quoc Hung vd cgng sir hi^n trudng tgi Long An, tren viing nudi ca be. C4c so ligu the hi^n trgn d6 thj chdng td cdc cam biln iam vigc 6n djnh trSn tSt ca 16 kenh do, gia trj DO do dugc trong khu vyc nudi cd long la nho, chi khoang tu I -2 mg/L. Dudng cao nhat tren hinh 5a la gia Irj DO do dugc khi cam biln dugc d§t ben ngoai khu vyc nudi ca long, phia ben ngoai song chdy dpng, gia trj DO do dugc tang len dang ke, nim trong khoang tir 5-6 mg/L.
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(a) kenh do so 1-5 be nuoi ca long, do ngay 6/6/2012 (b) kenh do so 6-9 be nuoi ca Idc, do ngay 6/6/2012
(c) kenh do so 1-5 be nuoi ca loc, do ngay 6/6/2012 (d) kenh do s6 6-9 be nuoi ca 16ng, do ngay 6/6/2012 Hmh 5: Bien Ihien DO do dugc tai khu vyc nuoi ca lai Ap Binh Hoa, Hoa Tay, Long An
4. KET LUAN
May do DO dieu khien bang may tinh ty chi tao, cho phep do dong thdi 16 kenh rieng bigt, ty dpng cac qua trinh do dgc, luu giir va the hien s6 ligu da lam vigc lien tuc, Ihdi gian dai mpt each on djnh vdi dp tin cay cao trong phong thi nghigm va ngoai hign trudng.
Phan mem dilu khiln qua trinh do dgc va xu ly s6 lieu cho may do va cho 16 kenh cam bien la phan mem than thign va de sir dung
So lieu do dugc Irong qua trinh Ihu nghigm cho thay cac cam bien dugc che tao va thilt bj co Ihl dugc su dung ngay trong cac nha may xu ly nudc thai, cac eg sd nuoi tr6ng thiiy san va cac d6i tugng nghien ciiu ckn quan trac DO. Hg thdng iam vigc ly d^ng, kit qua do dugc la khach quan va lien tyc, cho phdp theo doi ngay dem cac qua trinh biln d6i DO ngai ngheo.
Ldi cam on. Nghien cuu ndy dugc Du dn cita Bg Cong thuang, giai dogn 2009-2010 "Nghien cm che tgo hi thong do vd dieu chinh Hen tuc dong thai nong dg oxi hda tan phuc vu quan trdc vd dieu khien tu dgng hi thdng xic ly nuac thdi" tdi tra. I^om ldc gid xin chdn thdnh cdm an su hd trg ndy vd sugiup do cda Nhd mdy xii: ly nudc thdi Nam Sdch, Hai Duang; gia dinh ong Nguyen Tri Dong dp Binh Hda, xa Binh Hoa Tdy Huy^n Mgc Hda, Long An;
Sd Khoa hgc vd Cong nghe Long An.
TAI L1$U THAM KHAO
I. Allen J. Bard, Larry R. Faulkner. Electrochemical Methods, John Willey & Sons, INS. (2000) 2 Dang Thi To ND, Vu Thj Thu Ha, Vu Phiic Ho^g,
Phan Thj Ngpc Mai, Le Quoc Hung. Nghien cim chi Igo sensor sif dying vi dien cue vdng xdc dinh oxi hda tan trong moi trudng nudc, Tgp chi Hoa h^C 47(5A), 247-252 (2009).
TCHH, T. 50(6), 2012 Budc ddu ung dgng he do...
3. Vu Thj Thu Ha, Dang Thj T6 N&. Chi tgo vd nghien 4. Vu Thj Thu Ha, D?ng Thj T6 N&. So sdnh linh chdt cm tlnh chdt cua sensor oxi sir dgng vi diin cue cua sensor oxi kiiu Clark dugc che tgo lir cdc vgt vang dgng to hgp, Tgp chi Khoa hgc va Cong nghg, Uiu diin cifc khdc nhau, Tgp chi Khoa hgc va Cong 48(2), 39-46 (2010). nghg, 48(1), 81-85 (2010).
Lien h$: Le Qu6c Hiing
Vien Hoa hpc, Vien Khoa hpc va Cong nghg Vigt Nam 18 Hoang Quic Vigt, Cau Giay, Ha Npi
E-mail: [email protected].
