Cac thanh phan rac (trir rac thai hiru co) dugc chudn bj sdn vai do dm tir nhien trong nha CO mai che (khong bi nuoc mua hay bdt ki loai nuac nao bay thiic an nao lam not), rac thai hi[r]
Trang 1Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-01 J ^
ANH HUONG CUA MOI TRL ONG HOA HOC LEN HIEU QUA PHAN
HUY VI SLNH TRONG BAI CHON LAP RAC THAI
To Thi Hai Yen' Tran Thi Thu Nga' Nguyen The Dong', Trinh van Tuyen'
Kosuke Kawai', Saburo Matsui"
'Vien Cong nghe moi truong: 18 - Hoang Quoc \'iet Cau Giay Ha Xgi
"DH Nghien cim moi truong toan cau DHTH Kyoto Nhat Ban
Email: yenth59gyahoo.com Tom tat:
O cdc bdi chdn Idp rdc tritydi thdng nude rdc sinh ra cd do suy giam chdt him
ca nhanh nhimg sau dd bi chimg Igi vd cd bieu hien tdn tgi khd ben vimg trong thdi gian ddi lam anh huang nghidn trong den mdi truang Viec tgo ra su bien ddi mdi truang hda hoc (sunphat hdaj trong bdi chdn Idp dd ddy nhanh qud trinh
vd ca hda ddi vdi cdc thdnh phdn khd phdn huy vi sinh Nghien cim duac khao sdt
a cdc md hinh ddi chimg sdt vai dieu kien tu nhien cd vd khdng cd sir thay ddi mdi truang khao sdt qua cdc chi sd TOC IC
.Abstract:
At the conventional landfill sites, the organic pollution concentration in the leachate quickly decreased at the begining of its apparition, but Mas be seemed constant for long time, that seriously affects the ambient environment The microenvironment change creation Isulphatelization) in landfill lets conditions to promote, speed up the biodegradation of non-degradable organic constutuent The study investigated the control experiments modifications with natural, changed-microenvironment, and monitoring TOC IC parameters
1 M O DAU
Giai qu>"et 6 nhiem moi truang do nuac r6 ri tir bai chon lap la xan de ky thuat phiic tap khong chi rieng doi xoi nuoc ta ma ca tren the giod Do la nuac rac chira nhieu thanh phan
kho phan huy sinh hgc ga}' miii mau 6 nhiem keo dai chi phi xir ly ton kem Viec nghien cim nham khac phuc nhiing van de con ton tai tren da dugc nhieu cong trinh de cap
\'iec cham phan hu> mot so chiing loai rac trong bai chon lap rac thai sinh boat la giay xa
canh la cay - loai co chira thanh phan lignin tai 15.2% trgng lugng kho [3] gay ra yeu to phat thai khi metan rai rac keo dai noi bai chon lap la dieu khong co Igi cho kinh te \ a moi truang Cong trinh nghien cim cua Seog Ku Kim nam 1997 Dai hgc Kyoto ("N'hat Ban) [3] vod mo hinh bai chon lap rac la giay va canh la ca>- nuoc n rac dugc tuan hoan tro lai Ket qua cho iha>: trong mo hinh co moi truang sunphat lugng cacbon phan hiiy trong rac so vai a moi
truong metan truyen thong xay ra Ion hem xa di \ a o nuac ri rac ban che lugng phat thai
cacbon dioxit ^ao khong khi: khi metan ciing bi ban che sinh ra san pham o dang hydrosunphit trong nuoc n rac xuat hien nhieu hon
Nghien cim duoi day de cap van de xu ly rac thai sinh boat co chira thanh phdn gidv va canh la cay theo khao sat thuc te rac thai sinh boat do thi [1], tien hanh trong cac mo hinh bai
Trang 2chon lap tu nhien (moi tru6ng metan) va mo hinh bai chon idp c6 sir can thiep biin dli moi tru6ng thanh sunphat, sir tuan hoan nuoc rac Muc tieu ciia nghien cim nhdm khao sat sir biin doi cac thanh phan 6 nhiem trong nuoc ri rac (ting cacbon him co TOC, ting cacbon \ o co IC) theo thai gian tai cac mo hinh co thanh phan rac gilng nhau nhung moi truang hoa hgc khac nhau, keo theo no la hieu irng thuan Igi cho sir hoat dgng ciia cac chiing vi sinh khac nhau Ngoai ra, che do tuan hoan va khong tuan hoan nuoc rac anh huong din hieu sudt phan hiiy rac, so sanh cac ket qua nham rut ra cac ket luan vl mot phuong phap cong nghe moi trong chon lap rac thai, vl kha nang ap dung cho thuc tl
2 PHl/OTVG PHAP NGHIEN ClTU 2.1 Mo hinh thuc nghiem
Rac thai sinh boat do thi bao gom cac thanh phdn chu ylu voi trgng lugng tuong img [1] dugc
mo phong Cac thanh phan rac (trir rac thai hiru co) dugc chudn bj sdn vai do dm tir nhien trong nha CO mai che (khong bi nuoc mua hay bdt ki loai nuac nao bay thiic an nao lam not), rac thai hiiu CO idy tir thanh phan rac thai thuc phdm, rac thai vuon sau khi phan loai rac thai hg gia dinh ciia mot so khu dan cu trong thanh pho, rac nay co do dm tu nhien cua chinh no, khong bi not boi nuoc mua
Mo binh thi nghiem la 5 thiit bi phan ung (sau day dugc ggi va ki bieu la Rl, R2, R3 R4 R5) CO cau tao hinh tru diing, c6 dung tich 110 lit dugc chi tao bdng thep khong ri SUS 304,
CO son phu epoxy o mat trong, dugc lam kin khi va dugc kilm nghiem o ap sudt +20mmH2O, gioang kin nuoc va kin khi bang cao su bin trong moi truong axit, mo phong cac mo hinh ciia bai chon lap rac hgp ve sinh
Trong cac thiet bi, moi truong phan hiiy vi sinh la yem khi, tai thoi dilm d6ng ndp co dua vao mot lugng phan biin be phot la 50g cho moi kg rac Rac trong cac thiit bi dugc luoi voi lugng nuoc dam bao toi thieu 2 kg/ngay, mo phong theo lugng mua trung binh hang nam ciia khu vuc Ha Noi la 2000inm [2], tire khoang 2 lit nuac moi ngay; nuoc ri rac chay ra tii' moi thiet bi dugc tuoi lai toan bg cho thiet bi do (trir Rl), voi tru6ng hgp thiit bi c6 lugng nuac ri rac nh6 ban 2 kg/ngay thi nuoc tu nhien (6 day diing nuac cap tai v6i nuoc sinh boat) dugc them vao cho dii lugng 2 kg truoc khi tuoi vao thiet bi Nuoc ri rac dugc din tir day thiit bi dua vao be sinh hgc bieu khi co kem theo co cau gia da giup cho viec dilu chinh do cao ciia miic nuoc can duy tri trong thiet bi la 1/3 do cao ciia khoi rac B I sinh hgc hilu khi la binh chiia nuoc ri rac phuc vu cho tuan hoan deu co kich thuac hinh hgc giong nhau, dung tich ngan sue khi la 4,51it voi DO~6.5-7,4mg/lit, thai gian luu trung binh la 10 gio, lgc sinh hgc ngap nuoc bang plastic, co dien tich be mat rieng ~200m2/m3 Ngoai nhirng dilm chung nhu tren, cac thiet bi thi nghiem mang mot so dieu kien rieng nhu a bang 1
Bdng 1: Dieu kien ciia cdc md hinh thi nghiem
Md hinh thi nghiem
Rl
R2
R3
R4
R5
Tudn hodn nude rdc
Khong
Co
Co
Co
Co
Xic ly sinh hoc hieu khi
Khong
Co Khong
Co
Co
Them SO/'
Khong Khong Khong Ngay thir 33 Ngay thir 152
Ghi chii: SO/' cd hdm luang -lOOOmg/l trong nuac tudn hodn
Trang 3Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-013-7
2.2 Phuang phdp phdn tich
Cac chi tieu trong nuoc ri rac dugc khao sat la: do 6 xy hoa khir ORP; do pH; tong cacbon
hiru CO TOC, ting cacbon v6 co IC Phuong phap phan tich dugc ap dung the hien a bang 2
Bdng 2: Cdc chi tieu phdn tich
TT
1
2
3
4
Chi tieu
ORP
pH TOC
IC
Phuang phdp / Thiet bi
ORP-pH meter YSI - 5000 ORP-pH meter YSI - 5000 Standard Methods 5310 B; TOC Analyzer Shimadzu 4100 Standard Methods 5310 B; TOC Analyzer Shimadzu 4100
3 KET QUA VA THAO LUAN 3.1 Thanh phan TOC, IC trong nuoc rac
Bieu do hinh Iva 2 bieu dien sir bien thien ciia TOC va IC Su biin dli thanh phdn TOC
trong cac mo hinh co the chia ra may giai doan chinh sau:
TOC
350
300
250
^200
150
100
50
0
TOC
vA^
W- i- i
/ • f 0
• i \
'•V, \ i
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1 ^ t t vlTrrrt^
-150 200 250
- • — R l
100 200 300 400 500
R 2 — 4 — R 3 - 0 - R 4 • • - • - • - R 5 Thcyi g i a n , ngay - « — m • • • • • • • R2
300 350
T h o i gian, ngSy
- - 4 - - R3 — c
400 450
• • • - R5
500
Hinh 1: Su bien ddi TOC theo thdi gian ciia nude ri rdc trong cdc thiit bi thi nghiem
IC
1400
1200
_ 1000
I" 800
o 600
400
200
0
e
/ •
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/ / ^
8
-
t*^-* ^ i ^ l
n - & - - 0 - ' '
^ • • • 4
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1
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• • ' ^ i
Hinh 2: Su biin ddi IC theo thdi gian ciia nude ri rdc trong cdc thiet bi thi nghiem
100 200 300 400 500
Thai gian, ngay
-R2 — k — R 3 - O - R ^
Trang 4-I-Thai ky hinh thanh va giam nhanh: tir khi bat dau qua trinh thuc nghiem chon lap den ngay thir 67;
Thai ky tien on dinh (tir ngay thii 67 den 88) va on dinh a mirc thap (bat dau nga\- thir
88 keo dai den ngay thir 186) voi gia tri 320-530 giam dan den 258-341 nig/1 rieng Rl -100 mg/1 Thai ky nay c6 su bien doi moi truang trong R4 va R5 nen keo theo sir khac biet ve TOC a hai mo hinh do nhu sau:
Tai R4: moi tru6ng sunphat c6 tir ngay thir 33, nhung den ngay thii 95 thi gia tri TOC moi CO chieu huong tang va tang lien tuc, dat gia tri cao nhat 978 mg/1 o ngay thir 186
va bat dau giam
+ Tai R5: mac dii dang tren xu huong giam dan, nhung vod moi truong sunphat bat dau c6 tir ngay thir 152, khi TOC 6 gia tri 252 mg/1, thi den ngay 186, TOC tang nlianli len 341 mg/1
- Thai ky giam nhanh: Tir ngay 186 den 246 o tat ca cac mo hinh, TOC giam xuong den gia tri thap 5-25 mg/1, tire giam - 9 3 % a R1,R2,R3; a R4, R5 giam tai gia tri 67 va 110 mg/1 tire 81 % va 89 % tuong img
- Thoi ky giam cham den bet (tir ngay 246 - 452, den 480): a ngay thu- 452, TOC giam den 12 mg/1 a R4, R5, c6n 6 cac mo hinh khac gia tri nay thap ban, co khi dat toi < 1 mg/1; toi ngay 480, gia tri TOC o R4,R5 chi c6n 0,6, rieng a R1,R2,R3 thi gia tri nay lai tang len ban mot chut den 1-2 mg/1
Khao sat thanh phan IC o cac thiet bi thi nghiem, thay co sir bien doi theo cac moc thoi gian nhu sau:
- Thai ky tang nhanh:
+ CJ Rl: IC tang bat dau tir ngay dau tien den ngay thir 67, dat den gia tri cue dai (-194mg/l);
+ 0 R2, R3, R5, tic do tang IC Ion hon, keo dai thai gian hon, dat den gia tri cue dai
(~400mg/l) o ngay thir 74;
+ C) R4: IC tang nhanh tiep tuc ngay ca sau ngay thir 74, va tang den tan cuoi ky thi nghiem a ngay thir 452, dat cue dai 1300 mg/1;
- Thai ky I n dinh a mirc cao roi giam kha nhanh, on dinli 6 mirc thap:
+ 6 R l : IC In dinh vai ngay roi giam dan, sau do on dinh bat dau tir ngay thir 88 6 mirc thdp 125 mg/1 den sat cuoi ky thi nghiem;
+ C) R2, R3 R5: IC sau ngay thir 74 thi di vao on dinh trong khoang 20 ngay, nhung sau do lai bdt ddu giam ddn vao ngay thir 123 vai toe do gan nhu toe do tang trong giai doan ddu din gia tri 200-287 mg/1 6 ngay thir 186 roi on dinh va tang rat cham a miic thdp din culi ky thi nghiem; rieng doi voi R5, din ngay thir 214 thi tang tro lai kha nhanh, dat muc cue dai 600 mg/1 6 ngay thii 452;
Binh luan:
- Trong giai doan ddu (bdt ddu din ngay thir 67-88) TOC giam nhanh ciing luc IC tang
nhanh tire lugng cacbon him co trong nuoc ri rac nhanh ch6ng dugc v6 co boa; TOC giam xuing a mirc cao hon va IC tang nhanh va keo dai ban a R2, 3, 4, 5 la nod c6 tuan hoan nuoc ri rac;
Trang 5Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-013-7
+
+
Trong giai doan tiep theo (tir ngay thii 88 din culi ky thi nghiem):
0 Rl, R2, R3, TOC on dinh a miic thap, tuy nhien R2, R3 a cac miic do cao ban chiit
it do CO yeu to tuan hoan nuoc ri rac ciing luc do IC giam nhanh va duy tri o mirc
thap, tu'c trong nuoc ri rac luong cacbon hiiu co sinh ra rdt cham hoac hdu nhu khons
sinh ra tiep, nhung tinh trang nay lai keo dai den tan sau ngay thii 480;
6 R5 TOC tang tir ngay thii 152 thi tre ban mot chiit, vao ngay thir 186, IC bdt ddu
tang nhanh Trong khi TOC giam ddn thi IC tang ddn ciing liic din culi ky thi
nghiem, tire lugng cacbon hiru co trong nuac ri rac sinh ra lan hon va keo dai do tac
dyng cua moi tru6ng sunphat, va cimg voi no la lugng cacbon nay cung bi v6 ca hoa
lien sau do, ket thiic kha dirt dilm a ngay thir 480;
0 R4, TOC tang tra lai ngay tir ngay thii 95 sau khi co moi truang sunphat 62 ngay,
va vi le do ma IC tang lien tuc cho din tan culi ky thi nghiem, dat cac gia tri cue dai
deu Ion hon a cac R khac, tire cacbon hiru co trong nuoc ri rac dugc sinh ra lien tuc
manh liet hon va cung bi v6 co hoa khong ngimg, cho din hit a ngay thir 480
3.2 The oxy hoa-khir (ORP)
Theo [3], phan ung xay ra trong qua trinh phan buy vi sinh yim khi rac thai hiru co se la:
C'-H3(C'-H2)2C'-OOH + 2H'"20 ^ 2C^-H3C'"OOH + 2H°2 (1) (Butiric axit) (Axetic axit)
Axetie axit C^HsC^^OOH + 2H2O ^ C*-H4 + (HG^^Os)" (2) Trong moi tru6fng sunphat yIm khi:
+
CH3(CH2)2COOH
(Butiric axit)
1/2(S'"04) ^ 2 C^HsC^'OOH + l/2(HS'-) + 1/2H^ (3)
(Axetic axit) Axetic axit C^-H3C'"00H + (S'^"04)'- ^ 2(HG'"03)-+ (HS^T (4)
Phan img oxy boa - khu noi phan tir (1, 2), dac tnmg cho cac thiit bi khong co moi truang
sunphat (Rl, R2, R3, R5), bat dau tir ngay thir 60 tro di (hinh 3), thi oxy boa - khir luon co gia
tri duong (a Rl), tiic luon la phan ung oxy boa axit axetic thanh metan (phan img 2) nhung
cu6ng do kha yeu (ORP= 0-^20 mV), o R2, R3, R5 thi oxy boa - khir luon co gia tri am tire
khu hgp^chat huu co phiic tap xuong thanh bun co dan gian (phan img 1) da chilm uu thi,
nhung van voi cuong do chua cao Tru6ng hgp R4 co sir khac biet ro ret voi ORP=
-20 100-mV, phan ling khii hgp chat hiiu co phirc tap xuIng thanh hiru co don gian (phan irng 3) va
khu axit axetic thanh acid cacbonhydric (phan img 4) da chilm uu thi vuot troi xay ra ngay
cang manh het tinh den ngay thii 186, voi cuong do lan ban hdn so vol phan img (1 2) Dilu
do giai thich cho gia tri TOC va IC cao o R4 or ciing mot thai dilm khao sat vai cac tliilt bi thi
nghiem khac
Hinh 3: Su biin ddi ORP theo thdi gian ciia nude ri rdc trong cdc thiit bj thi nghiem
Trang 64 KET LUAN
Viec tuan hoan nuoc rac tao kha nang oxy hoa-khir manh hon cho moi truong phan hii}' \ i sinh cac chat bun co trong rac a the ran va v6 co hoa chat bun co a the long
Moi tru6ng sunphat bieu bien vai tr6 tich cue trong phan buy thanh phan chat hiin co o the ran trong rac vao the 16ng trong nuoc ri rac, v6 co hoa thanh phan hiiu co a the long the hien qua viec tao kha nang oxy hoa-khii- manh hon cho qua trinh phan buy rac bang vi sinh Bang each do ma tang kha nang thoi rira ciia dong rac va kha nang xir ly thanh phan him co kho phan hiiy vi sinh trong nuoc ri rac
Moi truong sunphat chi thuc su phat huy tac dung tir ngay thir 95 ciia chu trinh chon lap rac, mac dii moi truong ay da dugc tao ra tir ngay thir 33 ciia chu trinli nay
TAI LIEU THAM KHAO
1 World Bank, Ministry of Environment and Natural Resources, "Waste-Econ Project 2004
Vietnam Environment Monitor 2004 Solid Waste "
2 Tong cue thong ke Ha Noi 2006 "Nien gidm thdng ke 2005 "
3 Seog Ku Kim, Doctoral tesis, Biodegradation of Lignocellulosic material under
Sulfidogenic andMethanogenic Environments in Landfills", Japan, 1997
4 A.Hatakka et all, "Biodegradation of lignin in a compost environment: a review",
Bioresource Technology 72 (2000) 169-183 Elsevier
5 William K H Hogland, "Treatment of landfill leachate with reverse osmosis in Southern Sweden", Waste Management and Recorery Lund University, Sweden International
Congress: Waste Management - in crisis Sep 1996, South Africa
6 Remy GOURDON, "Qudn ly vd xic ly chdt thdi rdn Ndng cao gid tri chdt thai hang phuang phdp sinh hoc vd cdc vdn de d nhieng nai bi d nhiem ", INSA de Lyon-Compus de
la Doua, France Lop hgc chuyen de Viet - hap, 2002