Cong nghe xir ly nude thai bang phuang phap" Dat ngap nude nhan tao'' dugc tao bdi thire vat thuy sinh va cac Idp Ige da dugc ap dung d nhieu nude tren the gidi ke ca d cac nude phat tri
Trang 1DAI HOC QUOC GIA HA NOI TRUONG DAI HOC KHOA HOC Tl/NHIEN
^ ^ J i ^ ^ c ^ ^ ^ ^ ^
rEN DE TAI Nghien cuii vai tro ciia cac loai thuc vat thuy sinh va
vi khuan trong trong he thong dat ngap nirac nhan
MA SO: QT-06-39
CHU TRI DE T.\I (IIOAC DLJ AN: P C S T S Nguyen nii Loan
CAC CAN BO THAM GIA:
PC}S.rS lYinh r h i Thanh
- I'GS.TS Trim CAm Van
-CN Nguyen Xuan Lan
V ^
HA NOI - 2007
DAI HOC TPUNG Mr
DT
Trang 21 Bao cao torn t^t
a Ten de tdi (hoac duan), mdso
Nghien ciru vai tro ciia cac loai thi.re vat thuy sinh va vi khu^n trong he thong dat ngap nuac nhan tao de xu ly nuoe thai
Ma so: QT — 0 6 - 3 9
b Chu tri de tdi PGS.TS Nguyen Thi Loan
c Cdc cdn bo tham gia PGS.TS Trinh Thi Thanh
PGS.TS Tran Cam Van
KS Nguyen Xuan Lan
d, Miic tieu vd noi dung nghien ciiu
L Phan tieh cac chi tieu ly hoa nhu: BOD, COD, NH^, N O , , N O , , PO^ , tinh tong Coliform ciia nuac thai
2 llu'r nghiem cac loai thii'c vat khac nhau Irong trong he thong dat ngap nuac de lim ra loai thuc vat eho hieu qua xu ly nuac thai cao nhat
3 Phan lap cac loai vi khuan c6 boat tinh phan buy chat hCru ea cao
4 Nhan giong \'i khuain va dua vao he thong dat ngap nuac nhan tao
e Cdc ket qua dat duoc
+ Miic do 6 nhiem ciia nuac song To Lich tai khu vuc nghien cuu la tuong doi nang, ham luong PO, :2,52mg/K NI 14:9,85 mg/l,
COD:284 mg/l nuac song mau den, mui hoi thoi
+ Trong 4 loai ea> thi nghiem, ca}' say cho ket qua xir ly cao nhat (cac thong so eo the dirge xu ly tai 907^^), sau do den khoai nuac va ngo dai cudi citing la ran muong lliai gian luii nuac hop ly nhat cho viec xir ly
la 8 ngay
+ Cling mot thai gian lu'u nuac (8 nga}) nhung he thong ket hgp 3 loai cay cho kei qua tot ban ro rang, hieu qua xu ly cao ban 10-15% so vai trone cac loai thuc vat riene re * ^ • • < ^
-I- Hieu qua xu ly bang thuc vat the hien ro nhat d cac thong so: SS (87,9%), COD(80,8%c), PO,(84,8%) thong so NO, c6 ket qua xii" ly kem nhat (32,4%)
+ Trong 15 ehung \i khuan phan giai chat hiru ca dugc ebon d§ phan lap, cac ehung c6 kha nang phan lui\ tinh bgt xenllulo
Trang 3hemixenllulocao la 1 2 8, 1 1, 15 Trong do phan hii\ eua ehung 2 la cao
nhk (tao vong phan hu\ 4.8 cm sau 10 ngay) Toe do phan hiiy tang dan
iu ngay dau den ngay thir 8
-f Trong mau 11 dugc chon dung de xac djnh boat tinh phan giai ni
to hiru CO CO cac chiing 1 4 6 7 8 9 10 11 c6 kha nang phan giai ni to cao ehung so I 1 kha nang tao nhieu Nll.rnhat (voi pH Ion nhat la 8.5)
-I- Vi khuan dugc phan lap eo klia nang phan hu\' cac chat hiiu co
tot Ham luone NHi^ tane dan iix 8.7 me/1 len 14.6 me/1 \o*i 15 ml dieh
/ Tinh hinh kinh phi ciia de tdi (hocic dudn): da sir dimg bet so kinh phi
dugc phan bd
KIIOAQUAN LY (K\ \a <ihi ro ho ten) PosAL
Trang 42 Bao cao torn tat (tir 1-3 trang) b^ng tieng Anh
a Project Title Study role of aquatic macrophytes and Bacteria in a
constructed wetland to treat wastewater
Code: QT — 0 6 - 3 9
b Project Manager (hoac du an): Ass Prof Nguyen l l i i Loan
c Key implementers Ass Prof Trinh Thi ITianh
Ass Prof Ti\4n Cam Van Eng Nguyen Xuan Lan
d Objective and research content
1 Analyse physical and chemical parameters of wastewater, such as: BOD, COD, NH, , N O , , N O , , P 0 , \ calculate total Coliform
2 Grow different aquatic plants in a constructed wetland to find out the plant with the highest treatment efficiency
3 Indentify delTerent bacteria species with high activity of decomposing oreanie matter
4 Multiply indcntified bacteria and put into constructed wetland
e Main results
+ Tlie pollution degree of water o[ To Lich River is quite severe; water
color is black with bad smell I'he amount of some parameters are: PO, :2,52mg/l, NII,:9.85 mg/l, COD:284 mg/l
+ Among 4 experimental plants, the reed plant proxides athe highest treastment elfieienc) (the treatnient parameters can reach 90%) follows b\ water-taro fnxdra iluetuans Lour, then water morning glor\ The most suitable w ater retention time is 8 da> s
+ With the same retention time (8 days) the combination of all plants give higher treatment efficiency about 15% compared to a system with only one plant species
^ The treatment efficienc> can be seen throgh the following parametes :
SS (87,9%), COD (80,8%.), PO, (84,8%),^NO, parameter has lowest treatment effieiencx' (32,4%)
+ Among 15 bacterial species with organic matter decomposing activity, the species I 2, 8, I I 15 have higher decompossing activities for starch, xenlullor and hemixellulo Species 2 has a highest decomposing activity (decomposing c\cle was created 4.8 cm after 10 days) The decopsing acti\'ily increased gradually from the beginning untill the day 8th
+ Anrong 1 1 bacterial species selected to test the nitrogen decomposing acti\ity the species 1 4 6 7 8 9 10 11 have high nitrogen decompossing activit\' Species 1 1 has the highest efficiency by forming a
biggest amount oi NIL (with the highest pH which is 8.5)
Trang 5+ The combination between anaerobic tanks supplemented by organic mater and nitrogen decomposing bacteria with constructed wetland has increased treatnient efficiency of the treatment system
/ Financial situation of the Project: the total allocated budget has been
spent
Trang 6B PHAN CHINH BAO CAO
MUC LUC
Trang
1 Md DAU ^
2 TONG QUAN TAI LIEU ^
2.1 Gidi thieu ve cac loai dat ngap nude 9
2.2 Vai tro cua thiic vat thuy sinh trong he thong dat ngap 12
nude de xu ly nude thai
3.1 Ddi tugng nghien ciiii 16
3 9 ' 17
Phuang phap nghien cuu
4 KLT QUA VA THAO LUAN -^^
4.1
4.2
Ket qua thi nghiem chat lirgng nude song 1^") Lich
Ket qua xu' ly (mg/l), va hieu suat xir ly nude (%) d giai
doan 1 (he thong rieng bicl)
Ket qua \u ly va hieu suat xi'r ly nude d giai doan 2 (He
thong dugc ket ndi)
Ket qua phan lap vi sinh vat
4.5 Nudi cay va thu do phan buy cac chat hiru c a ciia vi sinh 26
^'^' KIHN NGlll CHO CAC NGIIIHN CUlJ TIRP THF.0
Trang 7L MO DAU
O nhiem nude dang la mot van de mdi trudng can dugc quan lam vi cac hau qua nghiem trong do nd gay ra Luu lugng va cac thanh phan chat thai nhu chat thai ehan nudi, chat thai benh vien, chat thai khach san, dau md chat ta[y rira, thai vao ngudn nude ngay eang tang Vdi ham lugng va thanh phan nhu vay cac ngudn nude bi trd nen d nhiem Cii the la mau nude ehuyen sang tdi hoac den, mui khd ehiu, nhieu mam benh xuat hien nguy hiem eho con ngirdi nhu ta, ly, thuang ban Dae biet la vao mi^ia mira khi ma eac vi sinh vat gap dieu kicn thuan Igi de phat trien, nhieu mam benh phat trien thanh dieh rat nguy hiem va khd kiem soat Ben eanh dd viec 6 nhiem nude lam anh hudng tdi sue khoe eon ngudi qua an udng, sinh boat hang ngay tir dd tich luy trong ca the
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xa thai, nghien cuu cac cdng nghe khac nhau eho viec xu ly Cong nghe xir ly nude thai bang phuang phap" Dat ngap nude nhan tao'' (dugc tao bdi thire vat thuy sinh va cac Idp Ige) da dugc ap dung d nhieu nude tren the gidi ke ca d cac nude phat trien: Canada, Uc.Viet Nam cung nen ap diing nhirng bien phap don gian, hieu qua re tien, than thien vdi mdi trudng nay vi dieu kien khi hau ciia Viet Nam rat thuan Igi cho sii* phat trien quanh nam cua cac loai thij'c vat thuy sinh sii* dung trong he thdng
dat ngap nude nhan tao Y^o chinh la ly do khien chiing tdi ebon de tai: 'Nghien ciiu vai tro cua cdc loai thuc vat thuy sinh vd vi khiidn trong
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Miic tieu ciia de tdi:
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Dam- Dai Kim
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Trang 82 TONG QUAN TAI LIEU
2.1 Gidi thieu ve cac loai dat ngap nude
Cd 3 he thdng dat ngap nude nhan tao la
1 Cac he thdng dira vao thue vat ndi tir do;
2 Cac he thdng dua vao thuc vat chim;
3 Cac he thdng dua vao thuc vat ndi tren mat nude cd re an sau dirdi day
2,1.1 Cac he thdng dua vao thuc vat ndi tii do
a, Cdc he thong dua vdo cdy beo tdy (beo Nhat Ban)
Cay beo tay la mot trong so cac thiJ'c vat cd anh hudng tot tdi iTidi trudng Nd la mot trong sd cac thuc vat sinh san nhieu nhat va ddng diie nhat tren the gidi Nhd dac diem nay ma nd dirge khai thae trong qua trinh
xu ly nude thai
Cac he thdng cay beo tay cd the dugc thiet ke de xij" ly nude thai ban dau ehira qua xu ly, lam sach ban nude da xu ly lan hai hoac de xiJ ly lan ba Sir loai bd chat ran la lung eua cay beo tay xay ra thdng qua ddi re Vdi mat do bao quan tdi thieu sir xao trgn nhiet, nhd dd ma cac chat ran la king se dugc lang dgng do trgng lire trong vung nude lang phfa dudi Them vao dd, d re cay cd sir tfch dien phan ling lai vdi nhung sir tich dien ddi nguge lai trong cac phan tu chat ran la lung, lam chiing dinh chat vao
re Cciy, tij' dd cluing dugc hap thii va ddng boa tij' tij" bdi cay beo va cac vi sinh vat
b Cdc he thdng trong cdy beo tdm,
Beo tam la loai thuc vat cd mach phd bien fong tren the gidi Chiing
cd mat trong cac vung nude nhd nhu ao ca, muang ranh, dam pha Chiing bao gdm kboang 35 loai trong 4 nhdm: Lemna, Pirodela, Wolffiella, Wolffia
Beo lam la mdi trong sd nhung thuc vat sinh trudng nhanh nhat tren the gidi Chiing ihudiig tang sinh khdi len gap hai lan d dieu kien tdi uu trong 2 den 3 ngay, d mot sd loai sir tang trudng ban dem Idn ban hoac bang sir lang truong ban ngay So vdi cay beo lay thi cay beo tam cd phan bddia ly rdng lion bdi vi chiing cd the sinh trudng d nhiet do thap lir 1 den 3^'C Beo tam cd nhirng dac diem lanr cho chiing cd kha nang xu* ly nude thai nhu:
1 Chiing sinh san tdt Vdi mdi ca the, 1 la luge nhd sinh ra 20 la luge con trong thai gian sdng Cac la luge eon nay lai lap lai nhu me nd Ket qua la sir tang trudng ngay eang nhanh, ft nhat cho tdi khi cac cay Ird nen bi qua lai hoac thieu chat dinh dudng Su ehuyen ddi tuan hoan lien tiep ciia cac ca} ihiic da\ sir sinh trudng ndi tiep lien Inc
2 Ca\ klione cd nhieu md ed de idn tai lau
3 Cay phan ling lai vdi sir giau chat dinh dudng, bien ddi vat chat vao md te bao
Trang 9So vdi ea\ beo tay, cay beo tam ddng mot vai trd kem true tiep han trong qua trinh xu ly, bdi vi chiing thieu mot he thdng rd sau va rdng, va
bdi the cung cap mot dien tich h6 mat nhd ban cho vi khualn Do vay, viec
sir diing cay beo tam cbii yen trong viec thu bdi chat dinh dudng tu nude
thai da dugc xir ly bac 2 Beo tam bao phii day dac tren ht mat nude ngan
chan su khueeh tan O, vao nude va ngan ehan su tao O do quang hgp \ i thieu anh sang Nude trd nen thieu O, nen quay trd lai sir phan nitrat boa
Sir hap thii anh sang ciia beo tam bao phii tren hi mat nude, ban che sir
sinh trudng eua thuc vat phii du, do dd tao chat ran la lung Beo tam ed kieh thudc nhd nen chiing nhay cam vdi gid, dieu nay ban dau ed the dSn den mot phan cua luu vuc khdng dirge bao phii, nhung trong thai gian dai
thi mot tham day beo tam se bao phii loan bd liai vuc Tham nay cung vl\n
nhay cam vdi gid, bdi vay cac ngan can nhd hoac eac be ndi dugc sii' dung thudng xuyen de giu" eac cay beo lam tren be mat
Viec su dung beo tain de xu ly nude thai khdng tdi nhu sir dung beo tay Thuc tc chi ra rang ehiie nang ehinh ciia beo tam trong he thdng dat ngap nude cd chieu sau dang ke la cung cap mot be mat bao phii ban la
loai bd trii'c tiep cac chai d nhiem Thai gian luu iru' nude trong cac he
thdng xii' ly dua \ a o cay beo tam phu thudc vao chai lugng nude thai, hieu qua ddi hdi, tdc do thu hoach va khi hau, nhuiig dien hinh la 30 ngay vao miia he va vai Ihane trone mua ddng Kich thudc tdi uu cho cac ao beo la dai: rone = 15: 1 de tao dieu kien eho ddne chay Mot he thdne man che hoac vach ngan khac la can Ihiei de ngan su" n^ii di cac thuc vat ndi nhd Cac he thdng thudng sau 3m
c Cdc he thong dua vdo cdc loai thuc vat ndi tu do khdc:
Cac he thdng dua vao cac loai thuc vat ndi tu do khac hiem han eac
he thdng cay beo tay hay beo tain Cac thuc vat ndi tu do dd bao gdm:
Rau ma ma (lixch'ocotylc umhellata) va rau diep nude (Pistia Stratiotes)
2.1.2 Cac he thdng dua vao thiic vat chim dudi nude
Cac thiie xat chim dudi nude ed md quang hop chim dudi nude Cac thi nghiem cho ihay kboang chat ed the dugc hap thu true tiep bdi cac md chdi ciia thuc \'al chim Tuy nhien, cac thue vat nay chi sinh trudng tdt trong nude ehiia O, do dd klidng the sii dung chiing trong viec xii" ly nude thai ed ndng do chai hiru ca cao.bdi vi phan buy ciia vi sinh vat chai hiru
CO' se tao ra dieu kien Ihieii dxy ^fhem vao dd, do due eiia nude khdng qua
cao de anh sang di qua thuan Igi cho sir quang hgp cua thuc vat Bdi vay, tiem nang sii dung cac thuc vat nay la cho xii ly nude thai bac 2 Su ed mat ciia thirc vat chim lam giam eac bon huu c a hoa lan va tang lugng O, hoa tan trong thdi ki quang hgp manh Dieu nay lam lang pH, tao dieu kien tdi uu eho sU bay hoi Nli^ va sir kei liia boa hoc ciia P Ndng do O, cao Cling tao dieu kien Ihfch hgp cho su kboang boa ciia \'al chai hu'u ca trone nude C^hai dinh du'dne du'oc ddne hoa hdi cac thu'c Mil du'oc du\ tii
10
Trang 10phan Idn trong cac md chdi cua eac cay va bdi cac vi kliuan bam dinh Viec mat chat dinh dudng tiJ tan la do sir gia yen ciia eac md dugc tieu thii mot each nhanh ehdng bdi nhdm vi kbuain bam dinh xung quanh cay
2.1.3 Cac he thdng dua vao thuc vat co re dudi day than noi tren mat nude
Cac he thdng xu ly nude thai vdi thue vat ed re dudi day, than ndi tren mat nude cd the dugc xay dung vdi nhieu md hinh khac nhau Ndi ehung eac he thdng nay ed the dugc phan thanh 3 nhdm ehinh theo md hinh dang ddng chay nhu:
a Cac he thdng chay tren be mat
b Cac he thdng vdi ddng chay ngang dudi mat dai
c Cac he thdng vdi ddng chay dudi be mat thdng diing
a, Cdc he thdng chay tren be mat (Free water surface FWS)
Nhirng he thdng nay thudng gdm cd: luu vuc chiia nude, hoac eac kcnh dan nude, \di Idp Idt ben dudi de ngan su rd ri nude, dat hoac eac Idp Ige Ihieh bap khac hd trg eho thue vat ndi Ldp nude ndng, idc do ddng chay chain va su cd mat cua nhan cay quyci dinh ddng chay va dac biet trong cac muong dai va hep, bao dam dieu kien ddng chay nhd (Reed
va cgng sir, 1998)
Cac vising dai ngap nude xir ly be mat tu do cd chue nang nhu la cac
he thdng xii' ly sinh hoc tap trung Nude thai chay vao ehiia cac chai la lii'ng va cac chai d nhiem boa tan trai rdng khap mot vung rdng ciia vung nude ndne C^ac chai ran la liine ed xu hudng on dinh \'a duoc eiu lai do tdc do ddng eha\ eham dugc che ehan gid Cac chai nay chiia N, P cac kim loai va chai huu ca Nhirng chai d nhiem khdng hoa tan nay cudi
cung di vao chu trinh sinh boa ca ban trong khdi nude va dai hi mat ciia
dat ngap nude Ddng thdi, mot phan chai huu ea, N P boa tan va cac nguyen to vet dirge hap thu bdi dai, vi khua!n boat ddng va mot sd thuc vat thdng qua mdi trii'diig dai ngap nude Nhirng nguyen to boa tan nay cung
di vao toan bd chu trinh kboang hoa cua he sinh thai dai ngap nude
Cac chat hu'u co' dugc loai bd nhanh ehdng trong cac he thdng l^'WS bdi cac dieu kien tinh lang su phan buy va qua trinh loe BOD boa tan dugc loai bd bai cac vi sinh vat lo" lung va bam dinh Ngudn dxy ehinh eho eac phan ling nay la cac phan ling tren mat nude Cac he thdng EWS loai bd mot each cd hieu qua cac chat ran la liing Trong eac he thdng d
dd thi hau bet cac chai ran dugc Ige va lang lai trong vai met nude dau tien cua ddng vao phia tren
Nita duoc loai bd cd hieu qua nhai trone eac he thdne FWS nhd su nitrat va phan ml rat boa NH^ dugc dxy hoa trong cac ddi hieu khf va NO dugc bien ddi liuinb N\ tu do hoac N^O trong cac ddi hieu khi bo'i \'i khualn phan nitrat (Yic he thdng FWS cd the loai P mot each lau dai nhune tuang ddi chani Sir loai bd P trone eac he thdne bWS xav ra nhd
Trang 11sir hap thu, hap phii, tao phiJc va kei tiia Tuy nhien qua trinh ehinh trong sir loai bd P (sij' kei tiia vdi ion Al, Fe, Ca) la bi gidi han bdi sir tiep xiie giiia tang nude va dat
b, Cdc he thdng vdi ddng chay ngang dudi mat ddt (Horizontal
subsurface JJow - HSF)
He thdng dugc ggi la ddng chay ngang vi nude thai dugc dua vao va chay eham qua tang Ige xdp dudi be eiia nen tren mot dudng ngang eho tdi khi nd tdi dugc nai ddng chay ra Trong sudt thdi gian nay, nude thai
se tiep xiic vdi mot mang ludi boat ddng eiia cac ddi hieu kJii, hiem khf va
ki khf Cac ddi hieu khf d xung quanh re va bau re, nai Igc O, vao trong
be mat Trong sudt thdi gian nude thai chay qua ddi r^, nd dugc lam sach bdi siJ' phan buy sinh hoc cua vi sinh vat bdi cac qua trinh boa, ly
Cac hgp chat huu co dugc phan huy hieu khf cung tdi nhu ki khf bdi
cac vi khusin bam dfnh xung quanh vung dudi eiia thuc vat (r6, bau vi) va
hi mat Idp Ige O, can thiei cho phan buy hieu khf dugc cung cap triic tiep bdi sii" khueeh tan ti^r khdng khf vao hoac tham O, til ri thuc vat Kha nang van ehuyen O, ciia cay say la khdng tuang ung di dam bao sir phan buy hieu khf trong ddi re va su phan buy ki khf ddng mot vai trd quan trgng
trong cac he thdne HSP\
Cac chat ran chim va la lung khdng dugc loai bd trong he thdng xii"
ly dau tien thi dugc loai bd cd hieu qua bdi su* loc va lang dgng Su lang dong se xay ra trong nhung vung dn dinh eiia bai ki he thdng IISI' nao
N-, dugc loai bd trong cac vung dai ngap nude HSF^ bdi sir nitrat va phan nitrat, sir bay hoi, hap thu Co" che loai bd ehfnh ciia N, la nitrat va phan nitrat N i l dugc dxy boa thanh NO^ bdi vi khuan nitrat trong ddi hieu khf va N O dugc ehuyen thanh N^ bdi vi khualn phan nitrat trong ddi
ki khf
Cac nghien euu da chi ra la qua trinh dxy hoa eua ddi re d cac he thdng HSF^ hi khong day du bdi the sir nitrat khdng hoan thanh la nguyen nhan ehfnh eua sir loai bo N bi han che Su bay hai, thuc vat hap thu, su hap phii ed vai trd quan trong ban nhieu trong su loai bd nita
P dugc loai bd khdi nude thai dau tien d eac he thdng HSF bdi eac phan li'ng trao ddi phdi tu, noi ma P0,(" chiem ehd nude hoac cac nhdm OH' ti^r be mat ciia Fe (OH), hay AKOII)^ Tuy nhien, ldp Igc sii" dung trone cac be thdng IISF^ thudne khdne chiia krone Idn Fe Al, Ca va bdi vay su* loai bd P ndi ehung chauT
c Cdc he thong vdi ddng chay thdng diing (Vertical subsurface flow
Trang 12He thdng dien hinh gdm 1 muong Idng dgng hoac phan bd so bd, 4 ngan Ige vdi dai hoac cat Mot he thdng thao nude va mot ranh di ra Nhirng ao Ige thi dugc trong cay say va ed mot he thdng thao nude sau 0,55m ben dudi miie be mat Nude thai sinh boat dugc chay vao mircyng lang sa bg va phan phdi Sau khi lang dgng, nude thai dugc trgn lan vdi nude be mat tii' 4 ngay Ba ngan khac dugc giu' khd kboang 10 den 11 ngay Kei qua chi ra la ed sir loai bd hoan toan cac chai d nhiem trong tang loe Chat lugng ddng ra ndi ehung la tdt
Trong cac he thdng ddng thang diing, Idp Igc dugc sii dung d tai ea eac nen be la sdi, tren eiing la cat vun de dat mot su phan phdi ed hieu qua eiia nude thai ngang qua nen day Nhung tang sdi thd thap hon dugc giu" hieu khf bdi eac dng thoat khdng khf Tai cac nen ddng chay thang diing da dugc dd day nude thai xii* ly Lin 1 trong 1 den 2 ngay, va dugc de khd 4 den 8 ngay Trong sudt thdi ky nghi ngai thi mot ldp ciing mdng Ccac chai ran do kboang boa cat dugc tao thanh
Hieu qua xu ly: Vdi xir ly bac hai: Tai ca cac he thdng dai ngap nude VF dugc md ta khac nhau deu loai bd tdi cac chai d nhiem, tru nita (bao gdm sir nitrat va nitrat) Nguyen nhan la do trong cac he thdng viec tao dieu kien hieu khf cung nhu yem khf cho su nitrat va phan nitrat la khd khan
Vdi xii ly bac ba: He thdng VF ap dung cho xii" ly lan 3 dat dugc ket qua tdt, tiie la thanh phan eac chai d nhiem d ddng ra rat thap
2.2 Vai trd cua thiic vat thuy sinh t r o n g he thdng dat ngap nude de xiJ ly nude thai
Cac loai ihire vat trong he thdng dai ngap nude bao gdm cac loai beo (beo tay, beo tam), cay say mot sd loai cd
Sii' ed mat bay vang mat ciia eac sinh vat thiiy sinh la mot trong sd cac dac diem de dinh ra mue dfch cac loai dai ngap nude, va bdi the thue vat thuy sinh la mot thanh phan khdng the thieu dugc ciia cac be sinh thai nay Mac di^i ngap nude la cac qua trinh vat ly va vi sinh nhung mot sd dac diem ciia thuc \ al thuy sinh cd lien quan tdi sir xii ly nude
a Trao do\ khf
liurc \'al irong he thdng dai ngap nude ihfch nghi \'c hinh thai vdi
sii* phat Iricii trong nude, dac biet hi chiing cd cac Id khf giiip cho sir van
ehuyen dxy vao vi va bau vi Su van ehuyen dxy vao than cay giup eho su
hd hap cua cac md ddng thdi cung cap cho ddi vi sii' thoat khf O, Chfnh nhd su thoat khi O lu vi lam tang diau kien dxy boa trong Idp nen ki khf,
kfch thfch su* phan huy hieu khf cac vat chai huu ca va su tang trudng cua
vi khiuin nitrat hoa
Su' \'an clui>en khf trong thuc \'al dai ngap nude cd the xay ra bdi su" khueeh tan do su chenh lech none do ha\ ap suai trong cac Id khf (Yic khf
se duae van chu> en tir noi ed ndng do cao hoac ap suat cao cd ndng do
Trang 13thap hoac ap suat thap ban Toe do khueeh tan phu thudc xao dac diem ldp Igc, phu thudc vao trgng lugng phan tir khf va nhiet do Cd su chenh lech dao nguge giOa ndng do O, vdi ndng do CO Cbj Trong cay say nong do O, giam til 20,7% trong than cay tiep xiic vdi khdng khf xudng
eon 3,6%6 trong cac Id khf d Idp vi sau nhat Ciing thdi diem dd, ndng do
CO, tang tii' 0,07% trong than cay tiep xuc vdi khdng khf len tdi 7,3% trong tang r^ sau nhat
Ngoai CO che van ehuyen khf bdi sir khueeh tan cdn ed ca che van
ehuyen kbi bdi sU truyen nhiet Su thoat nhiet la qua trinh van ehuyen khf
qua mot vach ngan xdp khi ed sir chenh lech nhiet do d hai ben vach ngan Sir thoat nhiet dan den mot sir chenh lech ap suat d hai ben vach ngan d mat am ban thi ap suat cao ban Ket qua la khdng khf se dugc van ehuyen theo ddng nhiet lir nai ed nhiet do cao deii noi ed nhiet do thap ban
b Ccie hieu qua vat ly
Hieu qua quan trgng nhai cua thuc vat thuy sinh trong qua trinh xiV
ly nude thai la cac hieu qua vat ly: dieu ehinh xdi mdn, hieu qua Igc, cung cap vising be mat cho vi khuan bam dfnh Sir trao ddi chai ciia thuc vat thuy sinh (hap thu, thai O, ) cd anh hudiig tdi cac qua trinh xu" ly tuy thudc vao md hinh thiei ke kliae nhau
Trong dai ngap nude, chiing phan bd lai va giam tdc do eac ludng
khdng khf tren mat nude Dieu nay tao ra cac d'\iu kien tdt cho sir lang
dgng cac chai i\in la king, giam xdi mdn, tang thdi gian tiep xiic giua nude va cac \Tuie be mat ciia cay Ngoai ra khi he re ciia thuc xat thuy sinh phcit trien chiing se ngan chan sir tac nghen cua ldp loe anh sang bi suy giam khi ehieu qua Idp phii thuc vat, dieu nay can trd sir sinh san ciia tao Vao mi^ia dong ldp phii thuc vat eon ed vai trd each nhiet giua khf
quyeii vdi vung dai ben dudi, giu' eho dat khdng bi suong gia Thuc vat
thuy sinh phat trien anh hudng tdi tinh dan nude ciia dat Re cay xao trgn lam xdp dat, dan dan se lam dn dinh tfnh dan nude cua dai
c Noi eu iiTJ eho \'i khuan
Ngoai ra ihuc \'al thuy sinh cdn cd cac chiic nang khac nhir cung cap noi sdng cho sinh vat hoang da Thuc vat thuy sinh cung cap vung be mat Idn cho eac vi sinh vat bam dfnh phat trien Phan than va la cua thuc vat thuy sinh chim trong nude tao mot vising be mat Idn cho eac sinh vat Cac nhdm tao quang hgp day dac eOng nhu vi kbuain va dgng vat dan bao xam chiem eac md thue vat Tuo'ng tu nhu vay, re cay chim dudi dai cung cap bd mat cho \ i khuiin bam dfnh Do vay, cac sinh vat xuat hien d eac
md tren va cho \ i khuan bam dfnh Do va)', cac sinh vat xuat hien d ca eac
md tren \ a md dudi cua thuc \al thuy sinh Nhung \i sinh \'at na\ cung
\'d'i cac \'i sinh \at bam dinh tren eac vat ran chim dudi nu'dc ehiu trach nhiem ehii yen cho cac qua trinh vi sinh xa)' ra trong he thdng dai ngap nude
d Hap thu chai dinh du'dn.e
Ccic thuc \at trong he thdng dai ngap nude ddi hdi cac chai dinh dudng cho sir sinh trirdng va sinh san Cluing hap thu chat dinh dudng
14
Trang 14thdng qua re va ddi khi thdng qua phan than va la chim dudi nude Chai dinh dudng dugc loai bd khdi he thdng nhd thu hoach sinh khdi Neu khdng thu hoach sinh khdi, lugng chu yeu chai dinh dudng trong md thue vat se bi phan buy va quay trd lai he thdng
e Diet vi khuan
Re eiia thue vat ngap nude cd the sinh ra mot sd chai, dac biet la cd
su thai ra O, vao trong tang re ed tac ddng tdi cac chu trinh sinh hoa ciia sir tram tieh Ngirdi ta dinh tfnh dieu nay nhd vao viec nhan biei dugc mau
hai dd lien quan deii dang dxyt sat tren be mat re Tdc do tao O, iix re phu
thudc vao ndng do O, ben trong te bao, nhu ciiu O ciia tang Igc va tfnh thaim than ciia mang re Vdi nhung loai thue vat ed he thdng v'an ehuyen khf bang su* tru\en nhiet kha nang sinh O, tu re cao ban so \'di cac loai thuc vat van ehu) en khf bang su khueeh tan Mot sd loai thue vat dai ngap nude ed the sinh ra chai khang sinh ti^r re cua nd Do dd cac vi khuan trong nude d nhiem bi bien mai sau khi eho di qua he thdng trong loai tbii'c vat nay Ngoai ra, mot luong Idn eac chai hu'u ea cung dugc tao ra tii"
ri eiia thue vat trong dai ngap nude Day la mot ngudn C bCai ca cung cap
cho qua trinh phan nitrat va do dd lam tang sir loai bd NO:; trong mdi sd loai dai ngap nude Cac vai trd chfnh ciia ihii'c vat thuy sinh dugc tdm tat trone Bane 2.1
Bang 2.1 Cac xai trd chfnh cua ihuc vat thuy sinh trong he thdng dai ngap nude
Bg phan thuc
vat
Md thue \at tiep
xiic vdi khdne
Vai trd trong cac qua trmh xii ly
• Su suy giam anh sang dan den giam sir sinh trirdng ciia thuc vat phu du
• Vi kJii hau bi anh hirong, each nhiet trong mua ddng
• Giam tdc do gid
• Tfch trii' chai dinh dudng
• Cd eac hieu qua Ige (loe qua cac md xdp)
• Gicim tdc do ddng c h a ) tang ty le tram tfch
• Cung cap dien tfch he mat cho VSV bam dfnh
• Su" tao 0 boi quang hgp tang sir phan hu)' hieu khf
• Hap thu chai dinh dudng
• Giiip dn dinh be mat lang dgng, giam xdi mdn
• Nean chan su uie nehen ldp loc trone he thdne ddng thang diing
• Sinh 0 lam tang su" phan buy hieu khf va su" nitrat boa
• Hap thu chai dmh dirdng
• Sinh ra cac chai khang sinh
Trang 153 DOI T U O N ( i VA PHUONG PHAP NGHIEN CUXJ
3.1 Ddi tugng nghien ciili
3.7.7 Ngudn nude sdng To Lich:
Sdng To Lich dugc bat ngudn tii* Hd Tay chay doc qua thanh phd theo Bac
- Nam Trudc khi dd vao sdng Nhue d Km 14 (llianb Liet) luu vuc Sdng
To Lich ed dien tfch kboang 7750 ha, luu lugng trung binh 5m7s, theo thdng ke hien nay nude thai sinh boat tai Ha Ndi khoang 300 - 400 ngan mVngay Tong khdi lugng rac thai sinh boat vao khoang 1800 -2000inVngay, \ a thu gom ehi dugc khoang 850mVngay phan cdn lai dugc
dd tuy tien ven ^ong cac chai thai sinh boat va cdng nghicp da dugc dd xudng ddng sdng ma khdng dirge qua cac he thdng xir ly nen da gay ra d nhiem mdi trudng tram trgng Bdi vay ma Sdng To Lich dugc xem nhu la cdng thoat nude thai chfnh cua thanh phd Doan sdng To Lich thudc kJiu vuc Linh Dam - Dai Kim chii yeu la nude thai sinh boat cua dan eu* xung quanh vdi miic do d nhiem Idn
3.1.2 Cdc lodi thuc vat thi nghiem
- Cdy tail niuofii^ nird'c (Ipomoea aquatica) : La loai sdng trdi ndi
dudi nude, thfch hgp nhai d nhiet do 25-30'^'C Re mge ti^r cac ddt dugc tiep xiic vdi dai am hoac vdi nude La rau hinh ludi mac dai khoang 10-15 em, cay cd the trone tu hat hoac tu mot doan cua than, ra neon nhanh klioang
2 thang cd the lane eap ddi sinh kJidi Rau mudne ed siic sdne manh liet trong mdi trudng d nhiem nang, kha nang hap thu cac chat tii* mdi trudng rat manh, ke ca cac chai kim loai nang Rau mudng phat trien manh nhai
d he vi chi^im, qua trinh hap thu cac chai cung dien ra d day nhd ban than
thuc vat va \ i sinli vat bam dfnh
- Cctx n;^(') (Fnydra fhictuans Lour) : Ca) thao sdng ndi ha)' ngap
nude, phan eanh nhieu cd ddt ^fhan hinh tru cd ranh la mgc ddi khdng cudne edc hai idne \ a dm la\' than, mep cd rane eu'a Hoa cai \-a hoa ludng tfnh deu sinh san Rau ngd cd the sii dung lam ran an thanh phan dinh dirdne( tfnh theo % ) : nude 92,2-93.8 protid 1.5-2.1 glucid 1.2, lipid
Trang 160,3, vitamin B2 0,29mg% va vitamin C l l m g % Cay ngo ra hoa ket qua hau nhu quanh nam nen kha nang tai sinh san nhanh, lugng sinh khd Idn.Pho bien d b^c bo va trung bo nude ta Ngo cd the phat trien manh trong nude ban, ehiu dugc khi hau da dang, nhiet do cao Kha nang lam sach nude rat tdt dac biet la khii miii hdi Kinh nghiem dan gian cho thay
d dau cd ngo la d dd nude trong va khdng cd miii hdi thdi
- Cdy say (Phragmites communis): Cd the sdng a khap noi dac
biet la khi hau ndng am, nhiet do moi trudng tdi uu la 12-30''C Ndng do mudi tdi da cd the ehiu dimg dugc la 45 %o Say cd the sdng trong muc
nude tu* 30 cm den 150 cm va trong khoang pH: 2-8 He vi ciia say phat
trien ra't nhanh, bam chac vao dat Khdng nhu cac cay khac tiep nhan oxy khdng khi qua khe hd ciia dat va rS, cay say cd ca cau van ehuyen oxy d
ben trong tiJ tren nggn cho tdi tan vi do vay say cd the chju dugc dieu kien khac nghiet, tdc do van ehuyen oxy tii* khdng khf xudng he ri va vung r^
rat nhanh 5-12g/m".ngay (Brit, 1990; Amstrong 1990) tao mdi trudng hieu khf cho viing rd, dugc vi sinh vat sir dung cho qua trinh phan buy boa hoc udc tinh sd lugng vi khuan trong dat quanh rd cay say cd the nhi6u nhu sd
vi khuan trong be hieu khi ky thuat ddng thdi phong phii ve chiing loai tii' 10-100 lan Chfnh vi vay eanh ddng lau say cd the xu ly dugc nhidu loai nude thai cd chat doc hai khac nhau va ndng do d nhilm Idn
3.2 Phuotig phap nghien ciru
Day la nhirng phuang phap thu thap nhiJng sd lieu, dii lieu cd sSn lien quan den noi dung de tai nham muc dich giam bdt thdi gian thuc hien, tang them logic ciia de tai De hoan thanh de tai nay chiing tdi da sir dung ngudn tai lieu sSn cd nhu sau:
- Mot sd tai lieu ve cac dir an nghien cuu trudc day va hien nay
- Tim tai lieu tii* mang internet
3.2,1 Cdc phuang phap phan tich chi tieu hod, ly
Cac chi tieu chiing tdi tien hanh phan lich danh gia tai phdng thf nghiem ciia khoa mdi trudng, trudng Dai Hoc Khoa Hoc Tu Nhien vdi su
OAI HOC O'J TPUNGTAf^: i n
^ DT 7^45
Trang 17hudng dan nhiet tinh eua can bd phdng thf nghiem Do vay kei qua chiing tdi phan tfch dugc hoan toan dang tin cay
Cac chi lieu va phuang phap phan tfch tijng chi tieu dugc trinh bay tdm tat trong bang 3.1
NO,
NO, Nil,/
PO,'
Dan vi
_
-mg/l mg/1-
mg/1-mg/l-
mg/1-Phuong phap phan tfch Diing thi giae
Diing khiiu giae Dung may do nhanh Phuang phap bieromat Phuang phap so mau Phuang phap so mau vdi thudc thu
4 - aminoben/en sufonamid Phuang phap Nessler (so mau) Phuang phap Molipdat (so mau)
3.2.2 Cdc phuong phdp phdn lap vi sinh vat
- Phu/] lap vi klindti
De phan lap vi khuan chiing tdi sir dung mdi trudng cd thanh phan:
- Peplon 10(g/l)
- NaCI 5(g/l) -Thach 20(g/l)
-Nude cai 2 lanlOOO(ml) Sau khi dun, mdi trudng dugc dua vao binh ndn khii trung d 120'^C, ap suai latm trong 30 phiit Mdi trudng sau khi hap dugc dua ra dTa petri
Can lOg vi cay rdi pha loang nhu tren thu dugc cac dng nghiem cd do pha
loang 1 0 M 0 \ 1 ( ) M 0 '
Dicing pipet 1ml nhd 1 gigl dung dieh cay len dia thach Dung que gap gat
diu mau tren thach Cay dung dieh tren 10 dla petri Bao gdi, nudi cay
trong tii ain d 3()"C
Sau 48h, lien hanh dein sd lugng khufin lac vi khuan va tfnh sd lugng vi khufin cd trong Ig mau(CPTI" ') theo cdng thiic
X=a.n.20 CFL-' ': Colony Forming Unit
18
Trang 18X: Sd lugng CPU trong Ig mau
a: Sd lugng CPU tren dia thach
n: Nghieh dao eua ndng do pha loang
- FeSO,0,l(g/h Nude cat 2 lanlOOO(ml)
Cac budc lam tuang tu nhu ddi vdi phan lap vi khuan
- Phdn lap nam moc
Chiing tdi sir diing mdi trudng Czapeck — Doc
- Nude eat 2 lan lOOO(ml)
Cac budc lam tuang tu nhu ddi vdi phan lap vi khuan
2.2.3 Thiet ke md hinh thi nghiem
Md hinh ihf nghiem trong thuc vat dugc thiei ke tuang tu* nhu* mang dan nude Kfch thudc mdi ihune la 0,7m x 0.7m x 1,5m
Cac loai thuc vat dugc trong trong 3 thiing
+ Thiine 1 tha rau mudne, muc nude cao khoang O.dm Mat dd trong cay phu hgp \di tu nhien
+ 1 hung 2 trong ngd dai va khoai nude, phfa dudi day ed Idp eat day 15 em nham ed dinh he re va la noi cu trii cua vi sinh vat
-I- Tilling 3 trong say, mat do cay khoang 20 cay/ni" Day thung ed Idp sdi nham cd dinh he re tang dien tfch tiep xiic vdi vi sinh vat
3.2.4 Thiet ke thi nghiem
Qua trinh thf nghiem dugc phan ehia lam 2 giai doan:
Trang 19Giai doan 1: Cac thiing dugc phan each nhu cac he thdng rieng biet Nude sdng dugc dd true tiep vao cac thung ehiia thuc vat D^tu tien
cac loai thue vat dugc trdng trong 1 tuan eho quen vdi diiu kien sdng mdi
Kei qua true quan eho thay sau 3 ngay eac loai thuc vat da bat dau thfch nghi vdi di6u kien mdi: than, la tuai Sau 7 ngay da bat dau ra nggn hay dam chdi mdi Tien hanh thay nude sdng mdi vao, bat dau qua trinh xii ly
Bat dau tij ngay luu nude thu 2, each 2 ngay lai lay mlu nude trong cac thiing khac nhau phan tfch 1 lan, tien hanh lay man 6 lan (tdng cdng thdi gian luu nude la 12 ngay)
Giai doan 2: Cac thung duoc ndi vdi nhau thanh 1 he thdng dan
nude theo so" do: (Rau mudng)—- (Ngd -\- Khoai nude)—- (Say) Cac
thi^ing dugc ndi vdi nhau nhd he thdng dng ndi, dicin dat dng each day 20em Cach 2 ngay luu nude lay mau nude phan tfch I lan, tien hanh lay mau 6 lan (Xem Bang 3.2)
Bang 3.2 Thdi gian lay miu nude trong hai giai doan
10 ngay
Lan 6
12 ngay
12 ngay
4 KET QUA Vy\ I H A O ELAN
4.1 Ket qua thi nghiem chat lugng nude song 16 Ejch
Trudc khi cho nude vao he thdng xii ly, chiing tdi lay 3 mau nude tu vi trf
lay man de phan tfch (Yic sd lieu phan tfch dugc dugc sii dung nhu* la cac
sd lieu ddi ehung (Bang 3.1)
Bang 3.1 Cac thdng sd boa ly tu* mau ddi chiing
NO,
(mg/l) 6,67 6,67 6,71
Nil,' (mg/l) 9,85 9,53 9,79
po,-(mg/1) 2,49 2,52 2,54
20
Trang 20( * ) 5-9 70 50 — 30 — 6
f*i.- TCVN 6772 cho nuac thdi sinh hogt- Gidi han 6 nhiem cho phep mirc I
Kei qua phan tfch cac thdng sd tren eho thay, trii* pH va NO^, cac thdng
sdhda ly cdn lai deu vugt qua tieu ehualn Viet Nam (TCVN) nhieu kin
nhu SS vugt qua TCVN khoang 7 lan, COD vugt khoang 4 lan Dieu nay
ehung minh rang nude sdng Td Lich dang bi d nhilm nang
4.2 Ket qua xu ly (mg/l), va hieu suat xii ly nude (%) a giai doan 1
(he thdng rieng biet)
O giai dt)an 1 chiing tdi thii* nghiem xii ly nude thai bang cac he thdng rieng biet nhu* he thdng ed trdng cay rau mudng, he thdng ed trdng cay rau ngd va khoai nude, he thdng ed trdng cay say de danh gia kha nang xu ly eiia lung loai cay ^fdng cdng cd 6 lan lay mlu, mdi lan each nhau 2 ngay Kei qua phan tfch cac thdng sd boa ly, va hieu suat xu ly so vdi mau ddi chiing dugc trinh bay d Bang 4.2
Bang 4.2 Cac thdng sd hoa ly ciia nude thai trong dgl 1
265 29,1 %
238 36,3%
220 41,1%
190 34,4%
173 40,3%
160 44,8%:
7.00 8.3%
6,87 10%
Lan 2 8,09 8,04 7,98
169 54,8%
154 58,8%
136 63,6%
133 54,1%
124 57,2%
100 65,5%
6,56 14,2%
6,41 16%
Lan 3 8,03
va hieu suat xu ly (%) Lan 4
8,02 8.06 8,04 8,00 ' 7,87
87 mg/l , 60
76,7% 1 83,9%
90 ! 57 75,9% ' 84,7%
72 80,7%
112 61,3%
89 69,3%
77 73,4%
6,47 15.1%
6,23 18,3%
47 87,4%
95 67,2%
77 73,4%
68 76,5%
6,22 18,27f
Lan 5 8,02 7,98 7,88
57 84,7%
50 86,6%
45 87,9%
90 68,9%
74 74,4%
65 75,8%
6.10 20,%
6,10 1 5,76 20,1% 24,6%
Lan 6 7,97 7,92 7,86
51 86,3%
48 87,1%
43 90,9%
87 70,0%
70 75,8%
63 78,2% 6,00 21,% 5,64 26,4%
Trang 216,11 8,94%
6,05 9,83%
5,87 12,5%
9,11 7,5%
8,87 9,31 % 8,36 14,6%
2,12 16,5%
2,09 17,7%
2.01 20,8%
6,29 17,6%
5,61 ^ 16,3%
6,00 10,5%
5,23 22%
8,34 15,3%
7.68 22,1%
6,83 30,6%
1,60 37%
1,45 42,2%
1,43 43,7%
6,21 5,78 18,7% , 24,3%
5,83 13,1%
5,89 12,2%
4,97 25,9%
7.61 22,7%
6.77 31,2%
5,87 40,4%
1,35 46,8%
1,12 55,9%
0,99 61,0%
5,78 13,8%
5,62 16,2%
4,79 28,6%
7,05 28,4%
6.32 35,8%
5,11 48,1%
1,02 59,8%
0,98 61,4%
0,75 70,4%
5,62 26,4%
5,69 15,2%
5,53 17,5%
4,71 29,8%
6.80 30,9%
6.11 37,9%
4,99 49,3%
1,01 60,2%
0,88 65,3%
0,69 72,8%
5.58 26,9% 5,60 16,5% 5,47 14,4% 4,68 30,2% 6.64 32,5% 5,98 39,2% 4,88 50,4% 0,97 61,8% 0,86 66,1% 0,66 74%
Kei qua phan tfch giai doan 1 eho thay cac thdng sd ciia nude thai deu giam theo thdi gian luu nude chiing td cac loai thue vat da the hien vai trd trong viec xii* ly nude thai Cd the thay rd cac thdng sd giam manh nhat la: SS (86-W7f), COD (70-78%), PO,^(61-74%) eac thdng sd N O / ,
giam ft la vi chira c6 cac di6u kien day du cho qua trinh phan nitrat xay ra
(nhu dieu kien thieu d xy va cd du ngudn cac bon)
Trong tai ca cac thdng sd xti ly cay say cho kei qua tdt nhai, kei qua xii ly deu hon cac loai khac 10-20% cay rau mudng cho kei qua xii ly
thap nhai Lv do cd the bg vi cua rau mudng khdng Idn va cay rau moc
22
Trang 22ndi Nhu vay phan cay dugc tiep xiie vdi nude khdng nh\iu kha nang loai
bd eac chat gay d nbi^m khdng cao (dac biet la vdi can la lung va COD)
4.3 Ket qua xu ly va hieu suat xii ly nude d giai doan 2 (He thdng dugc ket ndi)
Trong thf nghiem nay chiing tdi cho nu'dc thai chay qua ea 3 he thdng de danh gia hieu iiua xiV ly kei hgp cua cac loai thuc \'at thuy sinh Kei qua xii ly va hieu qiui xu ly so vdi mau ddi chiing dugc trinh bay d Bang 4.3 Bang 4.3 Cac thdng sd hoa ly eiia dgt 2
7,82 7,82 7,81
5-9
COD (mg/l)
151 47,9%
80 72,4%
61 78,9%
57 80,9%
55 82,3%
54 82,9%>
70
TSS (mg/l)
176 52,9%
89 76.2%
50 86.6%
44 87.9%
40 89,3%
37 89.7%
50
NO, (mB/1) 6,35 16,8%
5,65 26%
5.26 31,1%
5.01 32,8%
4,95 33,8%
4,83 33.1%
-NO, (mg/l) 5.41 19,3%
4,62 31,1%
4,05 39,6%
3.86 42,4%
3.80 43,3% ^ 3,76 44%
30
N H / (mg/l) 8,00 18,7 6,02 38,8%
4,78 51,7%
4,51 54,2%
4,34 55,9%
4,01 56,3%
-PO4' (mg/l) 1.84 27,5 1.13 55,5% 0.54 78,7%
0.46 81,8% 0,43 83,0% 0,42 84,1 %
6
Kei qua xii ly giai doan 2 tiep tue cho kei qua tdt, cac thdng sd d nhilm giam nhanh, cac thdng sd dat hieu suat xii* ly cao nhai van la: COD (80,3%), SS (89% ), PO,(83% ) Viec kei hgp cac loai thuc vat thuy sinh de xu* ly nude thai phan anh tinh hinh thiic te cua cac he thdng xii ly bang bien phap sinh hoc 1\iy hieu qua xii ly ciia tung loai cay ed khac nhau,
nhirng mdi loai cay lai co kha nang xii ly eac chai d nhidm khac nhau (thf
du, cay rau muong co kha nang hap thu kim loai nang nhu thuy ngan,
asen cao), nen he thdng ket hgp vAn la he thdng tdi irii
Hinh 4.1: 4.2; 4.3 so sanh rd hieu qua xu ly cua tiding loai thuc vat
thuv sinh ddi vdi cac chai gay d nhiim tieu bieu nhu COD, NII4 PO/