GIAI PHAP & CONG NGH6 XANH i W
Oe xuat giai phap xur ly nir6c rac phu hop v6i dieu kien Viet Nam
GS. TS.TRAN HIEU NHUE
Vien Ky thudt nUdc vd Cdng n^e Mdi trudng (IWEET)
ThS. LUONG NGOC K H A N H ^ - 1 . - 1 ^ v . . .
Cue Ha tdngKy thudt-Bg Xdy dung C a u h i n h m a n g v a m o d u l l o c
N
fldc rde hay nUdc ri rac la nUdc ban tham qua Idp rac efla d c d chdn lap, keo theo dc chat d nhilm tfl rac chdy vao tang dit d dudi bdi ebon lap (BCL). Nfldc rde cd mat tich cflc vd tilu cUc eho boat dpng cua BCL. Nfldc d n cho mdt sd qud trinh hda hpc vd sinh hpc dien ra khi phan huy rac hflu ca.Tuy nhien, nfldc cd the ldm xdi mdn dat vd tham trong tang nUdc ngam hay chay vao ngudn nUdc mat, gay d nhiem ngudn nUdc.
Nude rde dupe hinh thanh trong qua trinh chdn lap van hanh bai rdc vdi nhilu ngudn khac nhau nhU:
Nude sinh ra do qud trinh sinh bda phin buy d e chat hflu cd; MUc nfldc ngam ed thi dang len va ri qua eae vach cua d chdn rdc; Nflde tfl cic khu vifc khac chay qua cd thi tham vao rdc; Nflde mfla rdi xudng khu
A Hinh 1. Cdu hinh mdng vd modul loc cdc loai
Membrane system bay Kubota= He thdng mdng do Kubota che tao Flat-sheet membranes^Cdc tdm mdng lgc
Membranes rack = Hop ddt cdc tdm mdng (nhin ben ngodi)
vUe chdn lap rdc trflde khi phu dat vd trUde khi d rac ddng lai; NUdc mUa rdi xudng khu vUc BCL sau khi d rde day.
1. C O N G N G H E XU" LY N U d c R A C ( X L N R ) T R E N THE GlOl
Hiln nay, tren thi gidi dang ap dung 2 cdng nghe XLNR, dd Id:
Chu thich:
Vancouver Landfill - BCL chdt thdi ran tai Van-cu-vd;
Leachate Containment & Collection System - XLN rdc vd he thong thu gom.
Interim cover = Ldp phu Refuse - Ldp rdc
Demolition layer = Ldp phdn huy nUdc rdc Peat = Ldp than biin
Silty Clay = Ldp a cdt Sand - Ldp cdt
Perimeter dich = Miidng bao quanh Inner dich - MUdng trong (nUdc rdc);
Outer dich = MUdng ngodi
The higher outer dich creates a positives gradient which containes leaches in the innerdtch = MUdng ngodi cao hdn se tao dp lUc dUdngso vdi miidng trong chda nUdc rdc.
• Hinh 2. Sd dd thu gom, XLNR bdng cdng nghe thdm lgc tai BCL TP. Vancouver. Canada
So 8/2014 Mdl trddng 35
I GL\I PHAP & CONG N G H £ XANH J
Cdng nghe, ky thudt vlt ly, cd ly va hda hpc dp dung cdc quy trinh dieu hda, tuyin noi, Ipc d t truyen thdng.
Ipc mang (hinh 1) bao gdm: Sfl dung mang vi loc. (MF), tdi cd hgt 0,1 pm, silu loc (UF: Ipc tdi cd hgt 0,01 pm) de Ipe nfldc rac, sau do cho nfldc rdc da dupe xU ly tham thau ngUpc (RO), cudi cung xfl ly loc nano (NF), trung hda, keo tu kit tua. trao ddi idn, dxy bda nang eao bang dzdn, fentdn, hip phu edc thanh phan cdn lgi eiia nfldc rac. Mdi logi hinh edng nghe, diu cd flu nhflpc dilm nhat dinh ve d c khia canh xay dflng. ldp dat va van hdnh nin trong qud trinh nghien cflu khd thi va dy an dau tfl cu thi, ngfldi thilt kl phai so sanh vl vdn dau tU va chi phi van hanh de lUa eho cdng nghe phu hpp.
Cdng nghe, ky thudt sinh hpc ap dyng quy trinh ky khi UASB, AF, hieu khi anoxic, hieu klii (AAO, AO) dl xU Iy rde, sau dd dUa lUpng nflde rdc qua be phan flng mdng sinh hpc chuyen ddng (MBBR), bl phan Ung mang sinh hoe theo mc (SBBR) de Ipe, cudi cflng nfldc rac dupe dUa vao hd sinh hpc bode vdi bdi Ipe ngam trdng cay (hmh 2).
2. T H A N H PHAN TINH CHAT NUCfC R A C V A CONG NGHE A P DUNG XLNR TAI VIET NAM
2.1. Ket qud nghien cdu thdnh phdn, tinh chdt nUdc rdc d Viet Nam Tfl nhflng ndm 1990 - 1995, van dc xU ly d nhilm nfldc rdc da dflpc cac nha klioa hpc quan tam nghien eUu.
Diln hinh Id nhflng nghiln cflu cua Vien Khoa hoc va Ky thuat Mdi trUdng, trudng Dai hoc Xay dUng (CEFTIA);
Viln Cdng nghe Mdi trUdng - Viln Khoa hpc va Cdng nghe Viet Nam...
Kit qud nghien cflu eho thay thanh phan nUdc rac hflu eo (BOD, COD) va Nitd (T-N, NH,) rat eao d cae BCL rde Ml Tri, Tlianh Cdng, Thu Ll (Ha Ndi) vd bai rac Ddng Thanh (TP HCM) (bang 1); Khu xfl ly chat thai thi tran Quit Lam huyen Giao Thuy tinh Nam Djnh (bang 2).
361 Mdi trddng se 8/2014
Bang 1. Thanh phan tinh chat niidc rac BCL Nam Stfn vk Dong Thanh TR HCM
THANH PHAN D d N V j
pH COD BOD TSS VSS EC/TDS
NH.- N0j7N-N0^- N O j / N - N O ;
CI SO/
PC.'- ''TC 0 6 Cling tong cong
Do ciJng canxi As Cd Cu
^-
Pb Hg Nl Zn Tong Cciliform
mg/l mg/l mg/l mg/l ms/cm/ mg/l
mg/l mg/l mg/l mg/i mg/l mg/l mg/l mgCaCOj/l mgCaCOj/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l IVIPN/lOOml
BCL NAM SON*
5,3 - 8,3 3 000 - 45 000 2 000 - 30 000 200 - ! 000
326 17,43/-
10,32 12/- 0,148/-
"
43,35
.
Vet Vet
1x10-"
Vet
1 SOX 10''
B C L D O N G S THiJNH" ^
6,16 S4S57 42478 1560 1 180 -/18640
/ 0,024 /1,15 4 300 1 216 39,130
8400 6 200 0,18 0,02 4,1 0,2 1,05 0,0011
0,05 1,7
Ngudn : * Hudng ddn van hdnh tram XLNR Nam Sdn
^* CENTEMA 5-2000 Bang 2. Thanh phan nfldc rac tai Quat Lam, huyen Giao Thuy, tinh Nam
Khu xii ly chat thai thi triD Dinh
STT
1 2 3 4 5 6
8 9 10
'^ -
b_=_.
TENCHITIEU
pH Do d i n Do kiem TDS SO J NH . NO COD^ (KLl COD TSS N tong Ptong BOD Bo mau Pt-Co BOD,/COD
DONV!
m^/cm mgHCO 7L
mg/L mg/L mgNH VL mgNO A m g O / L m g O / L mg/L mg/L mgP/L mgO /L
KET QUA MIN
7.2 5,05 384 3517 127,9 13,5 0,4 221 117 18 17,9
<0,1 46 178 0,048
MAX 8,2 11,3 689 7153 : 441 197 3,4 __^
2382 M 1304 _ M
255 S
^^nj
7,8 Jk 513 J l 712_JI0,368___j
GIAI PHAP & CONG NGH$ XANH ^ M
m
Qua kit qua nghien cflu tren, cac chuyin gia da dUa ra cac danh gia cy the nhfl sau: Hiln nfldc ta chfl yeu ap dung phfldng phap chdn lap rac, lam compost, dot hay tao viln dot thu hdi nang lUpng... tuy nhiln cdc phUOng phdp nay diu chUa xfl ly dupe nUdc rac. Do do, mflc dp d nhilm eua nfldc rac d cde dd thi Viet Nam cao vd phflc t?p.
Nhflng do thi khdng phan loai va thu hoi nhflng vlt Heu cd the tai che, tli sfl dung, nhat la nhflng chit hflu cd ed the phin buy sinh hpc md dUa di chdn lap todn bd se ldm lang phi tai nguyen vd gay d nhilm mdi trfldng nfldc mat, nfldc ngam, khdng khi.
Ngoai ra, viec vdn hanh BCL, kl cd BCL hpp ve sinh nhflng thflc hiln khdng dung quy each edng vdi dieu kiln thdi tilt khi hau cua Viet Nam da anh hudng rit ldn ddi vdi thdnh phin tinh ehat nUdc rac, gly nhilu khd khan cho viec lUa chpn cdng ngh? phu hpp dl XLNR.
2.2. Mgt sd cdng nghe XLNR dd dUdc dp dung tai Viet Nam
Hiln cac tram XLNR d Viet Nam chu ylu dp dung md hinh hda hpc, bda ly, sinh hpc (CEEN) cua Cdng ty Minh Dflc, vdi quy trinh khep kin, nfldc rdc se dflpc dUa vao hd sinh hpc sau dd bom qua he thdng xfl ly I hieu khi bang bl alrdten vdi bun
B a n g 3 . C h £ t I t i O n g midc THONG s o
PH COD TongN TongP
SAUHdTlgPNHAN 5,8-6,8 2,650-6,850
225 - 586 3 3 - 4 2
q u a t i f n g c d n g SAU UASB
7,5 - 7,7 1.810-2,230
152-356 19-23
t r i n h c u a t r a m x A I y G o C a t SAU SBR
L 7.S - 7,9 550 - 780 88-165
12-19
HO SINH HOC 7,2 - 7,S 56-71 12-22 0,5-0,6
boat tinh, kit hpp thilu khi (andxic) vd thdi khi loai bd NH^, sau dd dUa vdo hd dn dinh vd xd ra ngodL Cd the ke den 2 tram XLNR dien hinh Id:
Tram XLNR tai BCL Gd Cat (TP.
HCM) dupe cac chuyen gia Ha Lan phdi hpp eung Viet Nam xay dUng, vdi cdng nghe hien dai va tien tiln, chi phi xly dUng khodng hdn 1 tieu USD vdo nam 2003. Cdng nghe xfl ly bao gom: Bl thu -> Tram bom ^ UASB kit hpp loai bd canxi -> XU ly hieu khi bang be alrdten vdi bun hoat tinh -> Lang -> Hd sinh hpc.
Nhin chung chit lUdng sau xfl ly dat tuong ddi tdt (bang 3).
Tram XLNR tai BCL Kilu Ky (Gia Lam-Hd Ndi): DU an do Xi nghiep Mdi tnldng Dd thi, huyen Gia Lam ldm ehu dau tfl, dang trong giai doan van hdnh thfl cdng trinh XLNR edng suit 150 mVngay. Nfldc rac dupe xU ly sau dd dUa ra hd sinh hoe hai bac, vdi ldm thoang nhan tao, trong hd cd trdng beo lue binh (beo tdy). Kl qua cho thiy, hilu qud xfl ly tdt. Chi tieu COD eua nUde dau ra dudi 100 mg/l.
3. DE XUAT G U I PHAP XLNR PHtJ H O P VCfl DIEU KIEN VIET NAM
Mgt Id, Viet Nam can khao sat, nghien cflu danh gia sU binh thdnh nUde rdc trong dieu kien eu the tflng dia phUdng, vflng mien; DU dodn, tinh toan cu the khdi Iflpng hinh thanh nflde rac va ddc dilm, mUc dp d nhilm hay ndng dp cac chat d nhilm trong nfldc rde.
Hai Id, xac dinh va Ifla chon ngudn tilp nhan nfldc rac sau xfl Iy (xa trflc tilp ra ngudn tilp nhan;
Xa ra mang Ifldi thodt nfldc thdi va xfl Iy chung vdi nfldc thai sinh hoat dd thi). Vile Ifla chpn nay phai phu hpp vdi diiu ki?n cua dia phudng.
Ba Id, nin ap dung cac loai hinh cdng nghe phu hpp, than thiln vdi mdi trUdng nhU: Cdng nghe tuyen noi, lang; edng nghe Ipc (loc cat truyin thdng, Ipe mdng theo modul, vi Ipe, loc nano); cdng nghe keo tu, dxy hda nang eao;
cdng nghe hieu khi, ky khi bay ky khi - hieu khi kit hop, cde loai binh nhfl UASB, Ipc ky khi, SBR, hd sinh hpe cde loai...; Sfl dung EM va cac loai hda chat thdng dung dl XLNR; Sfl dung cdng nghe Ipc hap phu, RO va cac loai hinh edng nghe, ky thuat khdc... Ddi vdi edc bai chdn lap nhd, lUdng nfldc rac tao thanh khdng nhilu thi hd sinh hoe ed lam thoang nhan tao kit hpp trdng thUe vat la phu hpp. Ddi vdi eae khu lien hpp va BCL ldn, ddi hdi cdng ngbl XLNR rat phUc tap bao gdm edng nghi sinh hpe ky khi ket hpp hilu khi eung vdi xfl ly hda hpe, vdt ly va cudi eung la bd sinh hpcB
56 8/2014 Mot trddng! 3:
