U SlAl \\h-\li
Nghien CLPU danh gia kha nang ap dung cong nghe tuyen noi ap lyc de XCP ly nu'ac mat phu hgp vai dieu kien Viet Nam
Ngay nhan bai: 20/7/2014 Ngay su^ bai: 5/8/2014 Ngay chap nhan dang: 10/8/2014
Nguyen M a n h Hung, Nguyen Viet Anh
T O M T A T :
Bdi bdo trinh bdy ket qua nghien cifu thttc nghiem vdi muc dich ddnh gid k h i nang dp dung cong nghe tuyen noi ap lUc de xii I^ ntfcfc mat trong dieu kien Viet Nam. Ktft qua cho thay, tuyln n6i dp lUc c6 hieu qua xi5 ly cao hcJn so vdi lang truyen thong. Do dye cua nil6c sau be lai^ thong thifdng tii 2-5NTU, trong khi do due cua nddc sau be tuyai noi dat <2.5NTU, nhcf do giam dttcfc tai trgng chat ban vao be Ipc va tang chu ky loc t^ 1,3-1.8 lan. Tren co sc(
do, tac gia da de xuat day chuyen xii ly nifcfc bang cong nghe tuyen noi dp lUc, v6i cdc thong so thiet ki va van hanh chinh nhii sau: i)Thc'i gian phdn ilng Tj,_j-10-18phut; ii) Ap suat bao h6a P|ji^^.5-4.8bar; iii) T^ 16 ndcic tuan hoan R~12-20%; iv) Thcfi gian lam vi^c trong vung tiep xuc T =1.0-2.0phut; v) Tai trgng thuy liic troi^ virng tach can v^ ^ =5-12mVm^.h.
Tff khoa: Xuf ty nufdc, keo tu, tuy«i noi ap lilc, dp d u e ABSTRACT
The paper presents results from experiments on dissolved air flotation assessing the applicability of dissolved air flotation (DAF) for surface water treatment in Vietnamese conditions. The results show^ed that, treatment efficiency of dissolved air flotation was higher than traditional sedimentation in terms of turbidity. Turbidity of treated water after DAF was beflow 2.5NTU, lower than average turbidity after conventional c o i ^ a t i o n - flocciilation - sedimentation (2-5NTU), This leads lo reduction of the solids and floes load on the following filters and increase of the filtration cycle up to 1,3-1.8 times. Based on the study results, the authors propose the water treatment line using DAF with related design and operation parameters as foUows: i) Flocculation time T^=10-18; ii) Saturation pressure P^|^=4.5-4.8bar; iii) Recycle ratio R=12-20; iv) Contact zone detention time T^=L0-2.0min; v) Hydraulic loading rate v^^, ^ 5-12m^/m2.h.
Key words: Water treatment, coagulation, dissolved air flotation, turbidity.
NCS Nguyen Manh Hiing
Cong ty Co phan Nilcic va Moi trifdng Viet Nam (VIWASE) E-mail; [email protected].
PGS.TS Nguyen Vi^t Anh
Vien Khoa hgc va Ky thuat Moi tnicing (lESE) TrilcJng Dg.i hgc Xdy diJng
E-mail: [email protected].
I.Datvande
Dmh hudng phat trien cap nudc d6 thj vd khu cong nghidp Vi^t Nam den nam 2025 vd tam nhin den nam 2050 duoc Chinh phCi phfi duyet ngay 20/11/2009. da lihang dinh vi&c sii dung nguon nUde cap cho sinh hoat theo hudng Uu tien khai thac nguon nUdc mat.Tuy nhien, hien nay chdt luong nguon nUdc mat ngay cang co nguy co bj 6 nhiem do phdi ti^p nhan nhieu nguon thdi khac nhau.
Cong nghe xCr ly nUdc mat hien nay ehCi yeu la keo tu - l^ng - loc truyen thdng. Cong nghe nay thUdng gap kho khan khi trong nguon nU6c tho co chiia eac can nhe, h^ keo tu nhien ben vCrng, kho keo tu. Neu quei trinh keo tu, lang khong hieu qud, thi cac cong trinh Ipc se ph^i lam viee vdi tdt trpng chat bin cao, ddn d^n phai rCfa be Ipc nhieu, gia thdnh sdn xuat nude tang, lang phi nU6c vk do rui ro tang.
Mpt trong nhung hudng khac phuc nhijfng kho khan va nguy CO dang doi mat tai cdc nhk may nudc trong khu vUe nhu da trinh bky 6 tren la cong nghe tuyen ndi ap luc. Cac ket qud nghien edu va thuc te ap dung 6 nhieu nUdc tren The gidi cho thdy cong ngh^ tuyen noi hp luc dac biet co hieu qud cao trong vi|c loai bd cac can ban, he keo cd kich thudc nh6 tao nen do due, do mau cua nudc NhCmg tap chat nay kho lang trong cac be Idng thdng thudng, nhung lai c6 the dinh bam va noi theo c^c bot khi kich thudc nh6 duoc hinh thanh hay dUa vao trong nUdc.
Cong nghe tuyen ndi ap life dUa tren nguyen tde bao hoei nude bdng khdng khi dudi ap suat cao, sau do dot ngot ha nhanh ap suat xuong bdng ap suat kht quyen. Khi dd xky ra qua trinh tach va hinh thanh cac bot khi ki'eh thudc rat nhd, tir 10-100 \im [trung binh Id eo^jm) 14]. Cdc bpt khi ndy van chuyen, keo theo cd cae bong c3n dfnh bdm vao chung vd ndi len tren mat nudc
Tuyen noi ap luc bao gom cac qud trinh; i) Qua trinh keo tu va tao b6ng, ii) Qu^ trinh tao bot khi; ill) Qua trinh tiep xuc va dinh bam giijia
bpt khi vk bong can trong vung tiep xuc cCia be t u y l n noi; iv) Qua trinh t i c h cae bot khi dinh bam vdi cac bong can ra khdi nude trong vung tach can cua be tuyen noi
Hlnh 1: So do cong nghe tuyen noi ap lUc 14]
Cong nghe tuyen noi ap lUe lan dau tien duoc nghien c u ^ ap dung trong xU ly nude d Phdn Lan vao nhOng nam 20 ciia the ky XX. Be tuyen noi thdi do cd hinh dang be dai, nong, tdi trpng thuy lUc dudi SmVm'.h [5], Trong nhifng nam 1970-1990, cong nghe tuyen noi da dUOc cJi ti^n nhieu, va kha nhieu nha may nUde ap dung c6ng nghe tuyen noi ap lUc da dupe xay dung 6 Bdc Au va Anh quoc. TU 36 t r d di, cdng nghe tuy^n noi ap lUc da duac p h d bien rong rai tr^n the gidi nhU mpt g\k\ phap thay thi be ldng truyen thdng. Cho den nay, tren the gidi, cdng nghe tuyen n 6 i a p l u c d U o e sir dung rpng rai trong linh vUc xir ly nude cap, nUde thai va xir ly biin cSn [7].
0 Vi^t Nam hien nay cdng nghe tuyen ndi ndl ehung va tuyen ndi kp iuc noi rieng mdi ch?
dupe ap dung trong ITnh vUc khai thhc khoang san vk xii ly nUde thki cdng nghigp Vi vay, viec nghidn CLTU va lam chO cdng nghe tuyen noi cip luc de kp d u n g mdt each phiJ hpp trong day c h u y i n x i l 1;^ nude cap cho sinh hoat vcri nguon nUdc mat ih viec lam can thiet Muc tieu ciia nghien ciru nay nhdm 3knh gia kha nang kp dung cong nghe tuyen ndi kp lire de xir ly nude mat phii hop vdi dieu kign Viet Nam. Cu the la de xuat day chuyen cdng nghe xCf ly nude ap dung cdng nghe va de xuat cac t h o n g sd thiet kd vh Vein hanh chinh cho cac qua trinh cita tuyen ndi ^p lUc.
2. V^t lieu va phUCng p h i p nghien cihj 2 . 1 . Nghien ciJTu trong phong thi nghiem Muc dich t h i nghiem Nghien cCnj thitc nghiem tren m d hinh tuyen ndi ap iuc vdi che do leim v i f c gian doan vh lien tuc nhdm: i) Ho^n thi^n dky c h u y i n cdng nghe va thiet bi eiia m d hmh thf nghiem; ii) Xdc dinh dupe khoSng gik tri cua che t h d n g so thiet ke, van hanh chinh cua
Ifinh 2 Mo hlnh thinghiem tu/en noi ip iuc Deft 1: Tir ngay 26/7/2008-29/7/2008, vdi muc dieh xac 3\nh khoSng gid t n lam viee ciia ap suat Irong t h i i n g bao hoa (P^^) de dat dupe hieu qua xif ly sau tuyen ndi tfnh theo d p due (NTU) la nhd nhat.
Dcrt 2; TU ngay 01/8/2008-04/8/2008, vdi muc dfch xac dinh k h o i n g gia trj lam v i f c ciia t y le nude tuan hoan (R) d l dat dUoc hieu qud xCf ly tinh theo dp due (NTU) la n h d nhat. Van hanh mo hinh t h i nghiem vdi eac khoang gia trj dp due ciia nUde tho NTU1 = 85, NTU2= 150, NTU3=
270, NTU4= 356, de xac d m h dUOc chat lUpng nude sau tuyen ndi tfnh theo do due (NTU) t u o n g Lfng vdi c^c gia tri eiia R.
Dot 3: Tii ngay 05/8/2008-08/8/2008, vdi mue dfch xac dinh khoang gia t n lam viec eua thdi gian phkn dng (tfu) cua qua trinh keo t u va tao bdng de dat duoc hieu qud xii iy tfnh theo d o due (NTU) la nhd nhat.
Lpc pha t r o n g b l Ipc vat lieu ndi - Keo t u - Ldng ly t a m ; li) Trdn hda chat, tkch khi - Ldng trong cd tang can lolCfng.
D o t 1: Tif ngay 17/9/2008-22/9/2008, vdi muc dfch xac dinh khoang gid tri lam viec eua tki t r p n g thCiy life trong v i i n g t ^ c h can (v^,,) d l dat dUdc hieu qud xif ly sau t u y l n ndi tfnh t h e o dp due (NTU) \k n h d nhdt. Van hanh m o hinh thf nghiem vdi PtK=4,6 bar va R=l 5%.
D o t 2: Ti^ ngay 23/9/2008-27/9/2008, vdi mue dich x i e djnh k h o i n g gia tri lam viee ciia
^u-hi ^ ^ ^^^ dugc hieu qua xif ly sau t u y e n ndi t i n h t h e o d d due (NTU) Id n h d nhat V i n hanh m d hinh thf nghiem vdi Pbh tang t i f 4.6bar l e n 4 . 8 b a r v i R = 1 5 % .
D p t 3: Tif ngay 28/9/2008-03/10/2008, vdi mue dfch x i e dinh khoang gia tri lam viee ciia v ^ ^ i de dat dupc h i f u q u i xCf \^ sau t u y e n ndl tfnh t h e o d d due (NTU) la n h d nhat. Van hanh m d hinh thf nghi&m vdi P,,,, t a n g t i ^ 4.6bar len 4.8bar va R tang t i f 15% len 18-20%.
2.3. Nghien ciifu d e xuat day chuyen cdng nghe, xac d i n h cac t h d n g so thiet ke, van hanh, cac ch[ tieu kinh te - ky t h u a t
Dua tren cdc k i t q u i nghien ciiu thUe nghiem, cac t i c g i i da d l xudt day e h u y i n xCf i'y nude ap d u n g cong nghe t u y l n n6i ap lUe de xCf ly nudc mat p h u hop vdi dieu kien V i f t Nam, vdi c i c t h d n g so thiet ke, van hanh ciia he t h o n g . Ben canh dd, n h d m nghien cifu da tien hdnh tinh toan xac d m h chi p h i dau t d va van hdnh ddi vdi NMN ap d u n g cdng nghe tuyen noi i p luc va so s i n h vdi NMN ap d u n g eong nghe lang vdi eac quy m d cdng suat t i f 5.000-100.000 m V ngd.
3. Ket qua nghien ciiu va thdo luan 3 . 1 . Ket qud nghien ciifu t r o n g phdng t h i nghiem:
e o t 1: Ti^ ngay 26/7/2008-29/7/2008, k i t q u i thf nghiem ciia d o t 1 d u o c t h e hien t r o n g hinh 4 dudi day.
Hinh 3b: Bot khi hinh thanh trong viing tiep xiic Bat 4: Tif ngay 09/8/2008-12/8/2008, vdi muc dieh xac dmh khoang gia t n lam viec ciia thcri gian lam viec trong viing tiep xiie (ttx) 3e dat dupe hieu q u i xif l^ tfnh theo dp due (NTU) la nhd nhdt.
2.2. Nghien ciJfu thUc nghiem tai nhd mdy nudc Thdi Binh
M d hinh t h i nghiem tai hien trudng duac dat tai nha may nUde (NMN) Thai Binh lay nudc t h d t i l sdng Tra Ly. D i y la ngudn nUde thudc he t h d n g sdng Hdng - sdng T h i l Binh. cd dp due Vila va Idn.
Muc dich thf nghiem' Xdc dinh c i c t h d n g sd lam viec ciia m d hinh vdi ngudn nude sdng Tra Ly vd so sanh hieu qua x i i ly eiia m d hinh tuyen ndl ap lUc vdi b l lang hien dang hoat d d n g d NMN Thai Binh theo d i y c h u y i n cdng nghe; i)
mj4^B6ducni,flcs.utuy^nno,^gva, thay adl Pbh D p due cua nudc t h o tif 1 3 4 . n R N T i i ^IA due cua nUdc sau f u - ^ n nd, o ^ M T , . ' -11 noi 3 5 N T U t u a n g i J n g
- 4.5-5.0bar.
'di khodng gia tn . Khi P^>5 bar, do du.- ., k h d n g g i i m t h e m nua, I'.r, bpt khi vdi kich thudc' vd b e t u y e n n d i l a m v i p c h i r - i Dot 2: Ta ngay O'.!;
q u i t h i nghiem ciia dot 2 hinh 5 dudi day
'i hdu n h u
• " t i ' a t n p . ^ d l t a o
• ' "^''-i h o p de 3,0bar.
• ; ' - ' 2 0 0 8 , k i t
• ' " ^ n ''•ong
ii^enniinfai 11.2014
D o t 1: Ti/ ngay 17/9/2008-22/9/2008. Vdn hanh m d hinh thf nghiem vdi Pt,^-^-& bar va R=15%, ket qua t h i nghiem ciia ddt 1 d u o c t h l hien trong hinh 8 dUdi day
Hinh 5: do due ciia nudc sau tuyen noi ifng vdi thay doi R Dp due eua nUdc sau tuyen ndi <2.5 NTU tifOng dng vdi k h o i n g gid trj ciia R=l 2-20%, tiiy thupe vao dp due ciia nudc t h d . Khi R >20%, dd due sau tuyen ndi hdu n h u khdng gidm them niia. K i t q u i thi nghidm eho thay khodng gia tri ciia R phii hcfp d l tuyen ndi Idm vi§c hi^u qud R=12-20%. De be tuyen ndi lam vlec hieu qua, phii tang R khi dd due ciia nUde t h d cao, eu t h l la: Dp due nude thd <100NTU, R =12-15%; Dp due ciia nUde t h d tif 100-200NTU, R=l S-20%; Dp due eiia nUdc t h d tif 200-300NTU, R=20-25%.
Dpt 3: Tif ngay 05/8/2008-08/8/2008, k i t qua thf nghiem ciia d o t 3 dUpc t h l hien trong hinh 6 dudi day
Hinh 6: fid due nifdc sau tuyen noi ling ven thay doi t^
D p due eiia nUde t h d tif 116-119NTU, do due cua nude sau tuyen noi <2.5 NTU tUOng dng vdi khodng gia tri t^^ eiia q u i trlnh keo tu v a t a o bdng tif t,^=10-18 phiit. Ciing can lUu y rang, t ^ ciia qua trlnh keo t u va tao bdng ttiy thudc vao loai ngudn nUde vd dang tdn tai eda he keo cd trong nUdc ngudn.
Dpt 4: Tif ngdy 09/8/2008-12/8/2008, icet q u i t i l l nghigm ciia d o t 4 dupc t h l hien trong hinh 7 dudi day.
Hinh 7 fio due cila nifdc sau tuyen ndi ung vcfl thay doi t^
Op due cua nUde t h d tCf 130-140NTU, d d due ciia nUde sau tuyen ndi <2.5NTU tUOng dng vdi khoang gia trj ciia t^=1.0-2.0phut. Khi t^ >
2phut, do due sau tuyen ndi hiu n h u khdng g i i m them nQa vk cd xu hudng tang len. K i t q u i t h i nghi§m cho thay khodng g i i tri ttx d l be tuyen ndi l i m viec hi§u qud t ^ = l ,0-2.0phut.
3a.Ketqu4nghi6ncClutaii NMN Thai Binh:
Hinh 8 Sd due ciia nirdc sau tuyen ndi dng vdi thay ddi tii trong thiiy lu'e trong viing tach can, vdi Pj|^=4.6bar, R=)5%
Vdi Pbh^-6 har va R=l 5%, dd due ciia nUde t h d tif 98-105NTU, dp due eiia nudc sau tuyen ndl <2.5 NTU tUong dng vdi khodng gia t n ciia V h i = 5-10mVm' h. Khi v^^ ^| <5mVm'.h, do due sau tuyen ndi hau nhu khdng gikm them nda va cd xu hudng tang len. K i t q u i t h i nghiem cho thay g i i tri ciia v^^ ^^ de be t u y l n ndi lam viec hieu q u i v^ 1^1= 5-1 OmVm'.h.
ditSitn Hlnh 10: Do due eua nifdc sau tuyen ndi dng vd thiiy luc trong viing tach can, vdi P^=4.8bar, R=15%
Vdi P^=4.8bar va R=l 5%, dp dye eua nudc t h d tif 93-108NTU, do due ciia nUde sau t u y l n ndi la <2.5NTU tuc*ng ifng vdi k h o i n g gia trj eda v^ |_, tif 5-12mVm'.h. Khi v ^ ^ , < 5mVm^.h, dp due sau tuyen ndi hau nhU khdng g i i m them nda va cd xu hudng tang len. Vi vay, vdi ket qud thf nghiem cho thay khoang gia tri ciia V h i ^ ^ ^^ tuyen noi lam viec hieu q u i v^^i^, =5- 12mVm^.h.
Opt 3: Tif ngay 28/9/2008-03/10/2008, V i n h i n h md hinh thf nghiem vdi P^ tang t d 4 . 6 l§n 4,8bar vd R tang tif 15% l e n l 8-20%, ket qud t h i nghidm ciia dot 3 dupe the hien trong hlnh 11 dudi day.
i- '<
Hmh 11,06 due eua nirde sau tuyen noi dlig vdi tai trong thiiy Inc trong viing tach can, vdi P^=4.8bar, R=lS-2a%
Vdi d d due ciia nude ngudn tif 130-190NTU, p h i i tang P^ tif 4 6bar len 4 8bar va tang Rtif 15% len 18-20% de d d due cua nUde sau tuyen ndl <2.5NTU tUong dng vdi khoang g i i tri ciia Vy 1^1=5-12mVm'.h. Vdi d p due ciia nude t h d t d 130-150NTU, t u a n g iitig vdi k h o i n g gia tri ciia v^^ ^=5-12mVm^h.Vdi dp due eiia nUdc t h d ttf 150-190NTU, de d p due ciia nUdc sau tuyen ndl la <2 5NTU tUong dng vdi k h o i n g gia t n ciia v ^ ,1=5-1 OmVm'.h.
So sanh dp due ciia nUdc sau md hinh t u y l n ndl vdi d d due cua nifdc sau be Idng dang hoat dpng eiia NMN
Trong qua trinh van hanh md hinh thi nghiem, t i l n hanh lay mau song song cua nUde sau be ldng hien dang hoat ddng ciia NMNThdi
Hinh Mi; Iflp can ndi tren be mat be luyen ndi Got 2. Tif ngay 23/9/2008-27/9/2008 V i n hanh md hinh t h i nghiem vdi P^„ t i n g t d 4.6bar len 4.8bar va R=15%, k i t q u i thi nghiem eda dot 2 duoe t h l hien trong hinh ID dUdi day.
H'inh 12'So sanh diat luong mfdc ciia md hinh Tuyen nil jp lue m diit lifong nifdc uu ldng tai NMN Thai Binh
Od due sau m d hinh tuyen ndi nhd han so vdi d d due sau be Idng eda NMN T h i i Binh Od
due thap nhat sau t u y l n nor dat 1,5NTU, trung binh dat 2.0NTU. Trong khi dd, chat luong nUdc sau be Ldng ly tam: thap nhat 2,8NTU, trung binh 5,6NTU; sau b l Ldng trona cd tana • n la idng cao nhat la 3.1 NTU nh=. - i i - Jng binh 2,7NTU
3.3 Oe xuat ap d y n g cong nghe tuyen noi Ap \Uc t r o n g x d ly nUdc mat
Day ehuyin x d Ij? nudc bdng cdng nghe tuyen ndi ap (Ue
Ttf ket q u i nghien cdu, de xuat day chuyen xif ly nudc bdng cdng nghe tuyen ndi i p lUe de x d (y nudc mat phii hop vdi dieu kien Viet Nam, cu t h I n h U s a u :
- D i y ehuyin cdng nghe: Day c h u y i n x d ly nude i p dung cdng nghe tuyen noi i p luc duoc t h l hien trong hinh ve 13 dudi day.
Hinh 13: So 86 dSy ehuyin x!i \j nudc ap dung cong nghe tuyen ndi de xuit
- Mo td d i y c h u y i n cflng ngh^: Nudc t h d dupc bom l^n b l trdn, sau dd c h i y sang b l p h i n ifng d l t^o bdng can rdi c h i y sang b l t u y l n ndi.
Ddng nudc bao hda khi qua cae vdi phun vao ngan t i l p xiie eiia be tuyen ndi, tai day c i c bat khi kfch thudc nhd duac hlnh thanh, t i l p xiie va dfnh bam vdi cae bdng can. Cae bpt khi va t d hop bdng can - bot khf duoe c h i y sang ngan t i c h c i n va duae ndi len be mat. Nude trong ddoc t h u d phia dudi day be tuyen ndi, sau do chdy sang be loc nhanh. Nudc sau loc dUoe khd triing va chay ve be ehda nUde sach,
O l xudt cac thdng sd ky thuat cua cdng nghe t u y l n ndi ap lUe
Tdket q u i nghien cdu, de xuat cac thdng sd thiet ke v i van hanh ehinh eho cae qua trinh cua t u y l n noi i p luc, cu the nhU sau:
Qua trlnh keo t u va tao bdng Cdc thdng sd t h i l t k l va van hanh cua qua trlnh keo t u va tao bdng nhu-Thdi gian trdn hda chat keo t u v i o nude; Cudng do khuay trdn eua be trdn va be p h i n ifng; Sd giai doan p h i n dng cho t u y l n ndl tuong t u n h u ldng.
Khic biet cua q u i trinh keo tu va tao bdng cho tuyen ndi va Idng chfnh la thdi gian phan dng.Thtri gian p h i n dng eua tuyen ndi nhd hon so vdi Idng de tao bdng can cd kich thudc nhd hon Thdi gian p h i n ifng eiia q u i trinh tao bdng ddi v6i qua trinh t u y l n ndi T,^=10-18 phut
Q u i trlnh tao bot khi
- Ty I? nudc tudn hoan R=10-15%, ddi vdi ngudn nudc cd d p due <100NTU, ty le nudc ludn hodn R=l 5-20% ddi vdi ngudn nude cd d p due t d 100-200NTU. Ddi vdi ngudn niidc cd dd due tCf 200-350 NT\J, t^ le tuan hoan R=20-30%.
- Ap sudt lam viec eua thiing baa hda: Ap
suat tfong thung bao hoa tCf P^^=4,2-5-0bar, ap sudt bao hda lam viec hieu qud P^„=4.5-5 Obar
-Thdi gian luu nUdctrong thiing bao hda tif 0,5 den 2 phiit, thong thudng 1,5 phut. LUdng khi cap vao rnUdc 6-12 g k h i / m ' .
Q u i trinh t i l p xuc
- Thdi gian tiep xuc. Thdi gian lUu nUde trong viing t i l p xiic thUdng tdT^=1-2.5 phdt, t i i trang thuy lUe eua vting t i l p xuc 100-200 m V m ' h .
- Kfch thudc bot khi Kfch thUdc ciia bot khi phy thudc i p suat lam viec ciia t h i i n g bao hda v i lUc cang be mat tchf - nUdc. Kich thUdc bot khi trong viing t i l p xuc tif 10 -100pm (trung binh I i 60pm).
- Ndng dd bpt khf trong v i i n g tiep xuc:
Ndng do bot khi cd t h l thay doi nhd viec thay ddi i p suat bao hda (P^^)hoac thay ddi fji le tuan hoan (R),
Qua trlnh t i e h can
- T i i trpng thiiy lLfe:Tii trong thu>J lUc eda vung t i c h can v^^ ,^1 = 5-12 mVm',h. Van tde dang eua bot khf va t d hop bot khi - bdng can la 20 mVm^h [5], ldn hdn tai trong thuy lue se dupe ndi tren mat nUde.
-T^ le ehieu dai (Ls) v i c h i l u rdng (Ws) ciia viing t i c h can Ls/Ws n^n < 4 t h d n g thudng = 2, chieu s i u be Hs= 2 0-3.5m
Xie dinh c i c chi tieu v l dau t d xay dUng va v i n hanh ciia cong nghe tuyen ndi i p lUe
Nhdm nghien edu da tien hanh tfnh t o i n xac dinh chi phi dau tU va van hanh ddi vdi NMN ap dung cdng nghe tuyen ndi ap lUc vd so sanh vdi NMN i p dung cdng nghe ldng vdi cac quy md cdng suat t d 5.000-100.000 m V n g d . K i t qud cu the n h u sau:
- Sudt ddu t u xay dUng NMN ap dung cdng nghe t u y l n ndi i p luc nhd hon 0.9-0.95 lan so vdi NMN ap dung cdng nghe ldng vi nhdng !y do sau: i) Chi phi xay dung cum be phdn dng - tuyen ndi nhd hon 0.65-0.75 lan so vdi xay dung cum be p h i n ifng lang, do thdi gian p h i n dng nhd han va t i i trpng thiiy lue ciia be tuyen ndi Idn han be lang; ii) Chi phf x d ly bim can ciia tuyen ndi nhd hon 0.9 lan so vdi ldng. do do am cua^can sau tuyen noi (93-95%) nhd hon so vdi do am eda can sau lang (97-99%).
- Chi phf v i n h i n h va b i o dUdng cua NMN i p dung cdng nghe tuyen noi i p lUc ldn hon 1,03-1,06 lan so vdi NMN ap dung cdng nghe lang vi nhCfngJy do sau: i) Mac dii chi p h i dien nang de rda b l loc tiet kiem duae 0,03-0,05kwh/
m^ nhung do ehu ky loc ciia b l loc sau be t u y l n ndi cung dUoc keo dai hon so vdi b l loc sau be lang t d 1,3-1,8 Idn.Tuy nhien, cdng n g h ^ tuyen ndl ap luc cdn tieu thu dien nang cha may bam tuan hoan nUde va may nen khi cap vao t h u n g bao hoa k h o i n g 0,1-0.15 kwh/m3-Vi vay, tong tieu thu dien nang eiia cong nghe tuyen ndi i p luc (0,4-0,6 kwh/m') ldn han 1,2-1,3 lan sa vdi edng nghe Idng truyen thdng (0,3-0,46 k w h / m3), ii) Chi phf van hanh ciia cdng trinh eua
eong trinh x d ly b u n c i n cua • j h e tuyen ndl ap iuc n h d hOn 0,85-0,9 I. "^' ' ^ " 9 ' d o a d am cua can sau tuyen ndi I -»*) " ^ d hOn so vdi d d am ciia can sau ldng b 98%).
4 . Ket l u a n , k i e n n g h i
Nghien cufu da cho thay edng nghe tuyen ndi i p Ide h o i n tohn cd t h e ap d u n g d e x d ly nudc mat p h u hop vdi dieu kien Viet Nam Ddy c h u y i n x d ly nddc ap d u n g cong nghe tuyen ndi i p luc duac de xudt n h u sau: Keo t u - T u y l n ndi ~ Loc nhanh. TrUdng h p p do due eua nude n g u d n >350 NTU nen bd sung t h e m b l so ldng.
Td k i t qud nghien cdu thue nghidm, da de xudt c i e t h d n g sd thiet ke vd vdn hanh eua cac cdng trinh trong day c h u y i n xCf ly nudc bdng cdng nghe t u y l n ndi dp lUc, eu t h l la: i) Thdi gian phdn Cfng t d T|^=10-18phdt; ii) A p suat t r o n g t h i i n g bao hda P^^=4,5-4.8bar; iii) T;^ le nude tuan hoan cap vao t h d n g ap Idc R=12- 20%, phdi tang t j le tudn hoan R l^n 20-25%
khi d p due cDa nddc t h d cao; iv) Thdi gian lam viec trong v i i n g t i l p xiie tdT|_=1.0-2.0phut; v) T i l trpng thDy l u e t r o n g v d n g t i e h can v^_|^|=5- 12mVm^h.
Cdng nghe tuyen ndi ap life cd hieu qud x d Ij? eao han so vdi ldng t r u y i n t h d n g , d p due cOa nude sau b l Idng t h d n g t h d d n g t d 2-5NTU, trong khi do due eda nudc sau b l t u y l n n6i
<2 5NTU, do do lam gidm t i l t r p n g chat ban vdo b l loc v i tang chu ky Ipc eda b l loc t d 1,3-1.8 lan. C i c chi tieu kinh t l - ky thudt khi so sanh tram x d ly nude vdi tuyen ndi dp luc cung cd nhieu Uu diem so vdi edng nghe truyen t h d n g ; t i l t kiem diSn tfch, gidm ehi p h i xif ly b d n , vd nhat la cdi thien chat lupng nddc. Cong nghi tuyen ndi dp lUc cdn duoc manh dan nghien cifu i p dung trong thUe tien, eho cd eac nha may nUdc mdi va cdi tao eac nha mdy nude eu, vdi edng nghe t r u y i n t h d n g .
TAILIEUTHAMKHAO
[1]. Nguyen Viet ftnh va nhdm nghien eiiu, Bao cao tong hop fle t^i nghien cuu phat trien cong nghe tuy&i noi ap lift de xd ly nudc va bun can trong xii iy nunc cap ad thi vdi nguon nudc mat d Ha noi, fle tai nghien cdu khoa hoc va phat tnen cdng nghe cap thanh pho, 2008
, * ! ™ " , r r . * " . * " * ' " ' " * * " * " t o j . vo ™ M M nuiih B0131,_kel qui n j h i , A, t i n , , , h f „ , , , j „ „ ^
[4]. Edzv^ald, J.K, Fundamentals of rii«ni„=.. ^ JoumalNEWWA,Vol.l21(;).ppaMi?/™r ''''''''"'
l5].Edzwaldit(,WaterOuj.||i,. ,,^7 , on Onnking Water, Sixth Edilion, M, r ^w H,ii ? ° ' " ' "^"'^*'°°''
16], Haarhoff, J„ and)V ' , ^i,, ii,!',.,'",' Modelling: Insights and Sh,. • • -' ' ' ^ ' " ' l"iotation
• - •• '^"' Water Supply '•'0, MA
^'m,n^ and ResearchandTechnology-. .
17]. Haarhoff, J. Oissolv.
prospectsfordrmiong water treaucf. ,^1,,^ , Intemabonal Conference on Rotatm-i .,„i'J.?''"^.'''"^'^^'*' •'"'•fiorea,;,Q07_
