- 1 -
M
M
DANH
DANH
M 1
1. M : 3
2. P : 3
3. N DUNG : 3
4. N 4
C 1: T QUAN 5
1.1. Q : 5
1.2. QUN NG TI VIT NAM 7
1.3. K 10
1.3.1. X 11
1.3.2. X - : 12
1.3.3. X SINH HC 13
1.3.4. X 14
1.4. T 16
1.4.1. S : 16
1.4.2. T QUAN
18
1.4.3. T QUAN V
NAM 19
1.4.4. T 21
1.4.5. T : 24
- 2 -
1.4.6. T
NC . 26
1.4.7. Y CHO
29
C 2: H KHU LIM - NINH 32
2.1. LIM - T DU 32
2.1.1. Q LIM
32
2.1.2. , KINH 32
2.1.3. QUY LIM 2020 36
2.2. H LIM 38
2.2.1. H 38
2.2.2. H 48
2.2.3. H
48
2.2.4. H LIM 49
2.3. H LIM 52
2.3.1. H
52
2.3.2. M C SINH
53
C 3: QUY LIM - T DU
- NINH 55
3.1. QUY L GIANG 55
3.1.1. G L GIANG 55
3.1.2. H 56
3.1.3. P QUY
L GIANG 59
3.2. L 62
- 3 -
3.2.1. C 62
3.2.3. L
SINH 69
3.2.3. SO 75
3.2.4. T MINH THIT
. 82
3.3. K MONG . 84
3.3.1. D , 84
3.3.2. NH SINH 85
3.3.3. ,
86
3.4. H KINH - MANG KHI QUY
87
C 4: 88
4.1. P TRONG 88
4.2. Y 89
4.3. C 89
4.4. C 91
4.4.1. X 91
4.4.2. C BAN 91
4.4.3. X 92
4.4.4. X 92
4.4.5. RA CHO
92
4.4.6. X 93
4.4.7. T KHAI 94
4.4.8. M KHI KHAI 95
4.5. M H 96
4.5.1. S : 96
- 4 -
4.5.2. C , : 96
K - 100
1. K 100
2. K 101
DANH THAM 103
THAM 105
P 1: H
KHI . 105
PH LC 2: MT NH V HIN TRNG NG
KHU VC 106
- 5 -
DANH
Bng 1.1: c tnh l - ho - sinh ca nc thi 25
Bng 1.2: Cht lng nc thi s dng trong nng nghip theo vi sinh vt 30
Bng 2.1: Hin trng s dng t khu vc th trn Lim. 34
Bng 2.2: Quy m dn s th trn tnh n 2020 37
Bng 2.3: Quy hoch s dng t ca th trn tnh n 2020 37
Bng 2.4: Cht lng nc thi Th trn Lim (ly ngy 5/11/2006) 38
Bng 2.5: Thnh phn v tnh cht nc thi sinh hot (ly ngy 11/3/2006) 39
Bng 2.6: Cht lng nc trn knh ni ng (ly ngy 5/11/2006) 43
Bng 2.7: Cht lng nc ao h(ly ngy 5/11/2006) 43
Bng 2.8: Cht lng nc ngm cha x l (ly ngy 5/11/2006) 44
Bng 2.9: Cht lng nc ging khoan (nm 2003) 45
Bng 2.10: Cht lng nc sinh hot (nc ngm qua x l) 46
Bng 2.11: Hm lng Cu, Zn, Pb, Cd trong cc mu bn, t 50
Bng 3.1: Dung tch b t hoi 67
Bng 3.2: Thi gian nc lu h k kh theo nhit v hiu qu 72
Bng 3.3: Tm tt cng ngh x l nc thi cho khu vc 80
Bng 3.4: Tm tt cng ngh x l nc th) 80
Bng 3.5: Kt qu x l nc thi d kin sc 82
Bng 3.6 :Hm lng ti a cho php ca cc kim loi nng i vi thc vt
trong t nng nghip (ppm) 84
- 6 -
DANH
Hnh 1.1. Cc phng php x l nc thi 11
Hnh 2.1 : Bn khu vc nghin cu 33
3.1: C ch qu trnh chuyn ho cht bn trong h sinh hc 70
Hnh 3.2. S h thng x l nc thi bng h sinh hc kt hp nui c 71
Hnh 3.3: M hnh x l nc thi h gia inh hay nhm h gia inh. 77
Hnh 3.4 Dy chuyn cng ngh x l nc thi - Phng n 1 78
Hnh 3.5. Dy chuyn cng ngh x l nc thi - phng n 2 78
Hnh 3.6: M hnh s dng hm Biogas np c nh. 79
Hnh 3.7. M hnh s dng ti kh Biogas bng cht do. 80
Hnh 3.8: S x l nc thi sinh hot h gia nh - gia 83
Hnh P.2.1. Hin trng x thi xung dng sng Tiu Tng 106
Hnh P.2.2. Hin trng dng sng Tiu Tng 107
Hnh P.2.3. Hin trng dng sng Tiu Tng 107
Hnh P.2.4. Mt gc nhn ra sng Tiu Tng 108
Hnh P.2.5. X thi trc tip vo sng Tiu Tng 108
Hnh P.2.6. Ngun nc t sng Tiu Tng 109
- 1 -
M
Th trn Lim nm pha Ty Bc ca tnh Bc Ninh, cch trung tm th x
Bc Ninh 5 km v pha Ty Nam v cch th H Ni 25 km v pha ng Bc.
Trc y khu vc ny l vng thun nng, phn b dn c tng i ng
u v c xem l c trng cho nng thn Min Bc ni ting vi cc ln iu
quan h. Cc lin anh, lin ch c th ht dao duyn mi khi tt n, xun v lc th
trn bn, di thuyn vui v m c bit l thn trung tm - thn Lng Giang c
dng sng Tiu Tng chy qua.
Hin nay, ng trc nn kinh t m ca vi v tr v iu kin t nhin sn
c l vng ven , nm trn trc ng 1A ni lin th H Ni vi ca khu
Lng Sn nn th trn Lim ang pht trin nhanh v chuyn dn t thun nng sang
nhiu lnh vc khc nh: nng nghip - cng nghip - thng mi - du lch v dch
v.
Theo ti liu thng k nm 2006, trong tng s din tch t nhin hn 512 ha
ca th trn th din tch t canh tc chim 300ha, din tch t dn c th trn l
80ha, cn li din tch t khc chim hn 100ha. Dn s ton th trn l 10.670
ngi thuc 2.400 h dn sinh sng, mt dn s trn ton th trn l 22.739
ngi/km2, t l tng dn s 1,2%. Tng s dn trong tui lao ng l 5.877
ngi trong lao ng phi nng nghip l 3.960 ngi chim 67% lao ng ca
th trn, ch yu lm trong cc ngnh tiu th cng nghip v kinh doanh dch v
thng mi.
X hi pht trin v tc th ha tng nhanh nn trn ton a bn th trn
ch c khong 20% s h thun nng, 5% s h lm ngh git m, cn li a phn
c ngh kinh doanh dch v, bun bn, c kh, mc, sa cha vi tng s cc c s
kinh doanh dch v trn a bn th trn l 1124 c s. Nh dn lin st nhau v xen
k vo gia l cc c s ch bin, sn xut ang x thi vo mi trng rt nhiu
loi cht thi khc nhau nh kh thi, cht thi rn v c bit l nc thi. Hn na
do th ha nn cc ao, h, sng trong khu vc ang b bi lp v rc, bi lp
xy nh v cc cht thi ang b tch t ngy cng nhiu gy nhim nghim trng
- 2 -
mi trng trong khu vc, lm phai nht dn nt p ca li ht quan h mi tt
n xun v. vng dn lin Anh, lin Ch cho thuyn ht i trn dng sng
Tiu Tng th mng v ngi dn trong khu vc ang phi hng ngy sng trong
mi trng b nhim ny.
Hng ngy, th trn Lim x ra mt lng ln nc thi, bao gm nc thi
cng nghip v nc thi sinh hot. Trong ngun nc thi c cha nhiu
nguyn t dinh dng nh nit, phtpho, rt cn cho cy trng. Cc nh khoa hc
t lu cnh bo khng c dng nc thi ca thnh ph trc tip ti rung.
Bi v trong ngun nc thi c cha rt nhiu nguyn t kim loi nng c hi
cho c th con ngi nh caimi, km, ch, thu ngn, v c cc cht hu c c
hi kh phn hy, cc loi vi trng gy bnh, v.v Nhng cht c hi trn u trc
tip gy nhim cho cy lng thc, rau qu v s li hu qu nghim trng cho
con ngi nu n phi.
Tt nhin khng v vy m chng ta b ph ngun nc thi ny. Chng ta
phi nghin cu tn dng ngun nc thi v tn ca thnh ph bng cch kh cc
nguyn t kim loi nng, cc cht hu c c hi v cc loi vi trng gy bnh, sau
mi ti cho ng rung. Nc thi thnh ph c x l ti cho cy trng
khng lm nhim lng thc, rau qu m cn lm tng sn lng cc loi cy
trng, ng thi lc sch thm ngun nc thi, gim bt nhim sng h. y l
phng php s dng nc thi khoa hc nht v ang c nhiu nc thc
hin.
Theo xu hng ny, vic nghin cu cc cng ngh x l nc thi ph hp
v a ra c mt m hnh qun l bo m pht trin bn vng ng thi gi
gn v pht huy cc nt p vn ha truyn thng th trn Lim l c ngha khoa
hc v thc tin cao.
thc hin nghin cu cc cng ngh x l nc thi v m hnh qun l
ph hp cho th trn Lim huyn Tin Du tnh Bc Ninh, cc cu hi nghin cu cn
gii quyt trong lun vn ny l:
- Hin trng mi trng trong khu vc nh th no?
- 3 -
- Nhng cng ngh x l nc thi no l ph hp?
- M hnh qun l mi trng no ph hp cho vic pht trin bn vng th trn
Lim?
- Nhng ai tham gia vo cc cng vic ny v mc n u?
1. M :
Mc tiu ch yu ca ti l nghin cu qun l mi trng cho pht trin
bn vng ti th trn Lim huyn Tin Du tnh Bc Ninh. Cc mc tiu c th l:
- nh gi hin trng, xu th v d bo cc vn v mi trng trong khu vc.
- a ra quy hoch v mi trng ti khu vc nghin cu.
- Nghin cu la chn cng ngh ph hp x l nc thi th v tiu th
cng nghip trong khu vc t tiu chun nc cho sn xut nng nghip.
- Nghin cu m hnh t chc qun l mi trng da vo cng ng.
2. P :
Nghin cu trn quan im pht trin bn vng l vn nghin cu mang
tnh tng hp cc ngun lc v cc iu kin t nhin, ti nguyn thin nhin, cc
iu kin kinh t, x hi v dn c. Vic thc hin cc ni dung phi da trn
nguyn tc v phng php tip cn nghin cu tng hp, do h thng cc
phng php nghin cu s bao gm t cc phng php nghin cu truyn thng,
h thng cc phng php iu tra x hi, nhn vn n cc phng php hin i
nh:
- Phng php kho st thc a;
- Phng php iu tra x hi hc;
- Phng php bn ;
- Phng php thng k, miu t, so snh;
- Phng php nh gi tc ng mi trng;
3. N DUNG :
- Nghin cu tng quan:
+ Thu thp, tng hp, phn tch cc ti liu, cc kt qu nghin cu trong v
ngoi nc v cng ngh, thit b x l v cc gii php ti s dng nc thi
- 4 -
th v cng nghip nhm nh gi kt qu, cc hn ch, tnh thc t v ph
hp trong iu kin Vit Nam.
+ Phn tch khung php l ang tn ti trong khu vc.
- Nghin cu chi tit khu vc:
+ iu tra nh gi hin trng mi trng (nc thi v cht thi rn).
+ Xy dng khung ch s mi trng.
+ nh gi ti nguyn thin nhin v him ha.
- Qui hoch thot nc v x l nc thi cho im la chn:
+ iu tra, kho st cc yu t phc v cng tc qui hoch.
+ Qui hoch x l nc thi cho th trn Lim.
+ Hiu qu kinh t - x hi - mi trng sau quy hoch.
- Nghin cu la chn cng ngh, thit b x l v ti s dng nc thi th ph
hp vi tng loi nc thi phc v nng nghip.
- Nghin cu m hnh t chc qun l x l v ti s dng nc thi:
+ a ra m hnh t chc qun l
+ Ch ra cc bc t chc qun l vn hnh.
+ a ra quy trnh vn hnh.
4. N
+ Qui hoch x l nc thi cho pht trin bn vng th trn Lim.
+ La chn cc loi cng ngh x l ph hp vi tng loi nc thi da trn
nguyn tc: cng ngh n gin, r tin, d qun l, vn hnh v tn dng ti
a cc iu kin sn c ca a phng.
+ xut phng php xy dng m hnh qun l mi trng da vo cng
ng.
- 5 -
CG 1: T QUAN
1.1. Q :
"Qun l mi trng l tng hp cc bin php, lut php, chnh sch kinh t, k
thut, x hi thch hp nhm bo v cht lng mi trng sng v pht trin bn
vng kinh t x hi quc gia".
Qun l nh nc v mi trng thc hin cc mc tiu ch yu sau:
- Khc phc v phng chng suy thoi, nhim mi trng pht sinh trong hot
ng sng ca con ngi.
- Pht trin bn vng kinh t v x hi quc gia theo 9 nguyn tc ca mt x hi
bn vng do hi ngh Rio-92 xut. Cc kha cnh ca pht trin bn vng bao
gm: Pht trin bn vng kinh t, bo v cc ngun ti nguyn thin nhin,
khng to ra nhim v suy thoi cht lung mi trng sng, nng cao s vn
minh v cng bng x hi.
- Xy dng cc cng c c hiu lc qun l mi trng quc gia v cc vng lnh
th. Cc cng c trn phi thch hp cho tng ngnh, tng a phng v cng
ng dn c.
Cc nguyn tc ch yu ca cng tc qun l mi trng bao gm:
- Hng cng tc qun l mi trng ti mc tiu pht trin bn vng kinh t x
hi t nc, gi cn bng gia pht trin v bo v mi trng.
- Kt hp cc mc tiu quc t - quc gia - vng lnh th v cng ng dn c
trong vic qun l mi trng.
- Qun l mi trng cn c thc hin bng nhiu bin php v cng c tng
hp thch hp.
- Phng chng, ngn nga tai bin v suy thoi mi trng cn c u tin hn
vic phi x l, hi phc mi trng nu gy ra nhim mi trng.
- Ngi gy nhim phi tr tin cho cc tn tht do nhim mi trng gy ra
v cc chi ph x l, hi phc mi trng b nhim. Ngi s dng cc thnh
phn mi trng phi tr tin cho vic s dng gy ra nhim .
- 6 -
Cc nguyn tc qun l mi trng, cc cng c thc hin vic gim st cht lng
mi trng, cc phng php x l mi trng b nhim c xy dng trn c
s s hnh thnh v pht trin ngnh khoa hc mi trng.
Nh s quan tm cao ca cc nh khoa hc th gii, trong thi gian t
nm 1960 n nay nhiu s liu, ti liu nghin cu v mi trng c tng kt
v bin son thnh cc gio trnh, chuyn kho. Trong , c nhiu ti liu c s,
phng php lun nghin cu mi trng, cc nguyn l v quy lut mi trng.
Nh k thut v cng ngh mi trng, cc vn nhim do hot ng sn
xut ca con ngi ang c nghin cu, x l hoc phng trnh, ngn nga. Cc
k thut phn tch, o c, gim st cht lng mi trng nh k thut vin thm,
tin hc c pht trin nhiu nc pht trin trn th gii.
Qun l mi trng c hnh thnh trong bi cnh ca nn kinh t th trng v
thc hin iu tit x hi thng qua cc cng c kinh t.
Trong nn kinh t th trng, hot ng pht trin v sn xut ca ci vt
cht din ra di sc p ca s trao i hng ho theo gi tr. Loi hng ho c cht
lng tt v gi thnh r s c tiu th nhanh. Trong khi , loi hng ho km
cht lng v t s khng c ch ng. V vy, chng ta c th dng cc phng
php v cng c kinh t nh gi v nh hng hot ng pht trin sn xut c
li cho cng tc bo v mi trng.
Cc cng c kinh t rt a dng gm cc loi thu, ph v l ph, cota
nhim, quy ch ng gp c bi hon, tr cp kinh t, nhn sinh thi, h thng cc
tiu chun ISO. Mt s v d v phn tch kinh t trong qun l ti nguyn v mi
trng nh la chn sn lng ti u cho mt hot ng sn xut c sinh ra
nhim Q no , hoc xc nh mc khai thc hp l ti nguyn ti to v.v
C s lut php ca qun l mi trng l cc vn bn v lut quc t v lut quc
gia v lnh vc mi trng.
Tnh thng nht ca h thng "T nhin - Con ngi - X hi" i hi vic
gii quyt vn mi trng v thc hin cng tc qun l mi trng phi ton
din v h thng. Con ngi nm bt ci ngun s thng nht , phi a ra cc
- 7 -
phng sch thch hp gii quyt cc mu thun ny sinh trong h thng . V
chnh con ngi gp phn quan trng vo vic ph v tt yu khch quan l s
thng nht gia t nhin - con ngi - x hi. S hnh thnh nhng chuyn ngnh
khoa hc nh qun l mi trng, sinh thi nhn vn l s tm kim ca con ngi
nhm nm bt v gii quyt cc mu thun, tnh thng nht ca h thng "T nhin
- Con ngi - X hi".
Tm li:
Qun l mi trng cu ni gia khoa hc mi trng vi h thng t nhin
- con ngi - x hi c pht trin trn nn pht trin ca cc b mn chuyn
ngnh.
Lut quc t v mi trng l tng th cc nguyn tc, quy phm quc t
iu chnh mi quan h gia cc quc gia, gia quc gia v t chc quc t trong
vic ngn chn, loi tr thit hi gy ra cho mi trng ca tng quc gia v mi
trng ngoi phm vi tn ph quc gia. Cc vn bn lut quc t v mi trng
c hnh thnh mt cch chnh thc t th k XIX v u th k XX, gia cc
quc gia chu u, chu M, chu Phi. T hi ngh quc t v "Mi trng con
ngi" t chc nm 1972 ti Thu in v sau Hi ngh thng nh Rio 92 c rt
nhiu vn bn v lut quc t c son tho v k kt. Cho n nay c hng
nghn cc vn bn lut quc t v mi trng, trong nhiu vn bn c chnh
ph Vit Nam tham gia k kt.
1.2. QUN NG TI VIT NAM
Trong phm vi quc gia, vn mi trng c cp trong nhiu b lut,
trong Lut Bo v Mi trng c quc hi nc Vit Nam thng qua ngy
27/12/1993 l vn bn quan trng nht. Chnh ph ban hnh Ngh nh 175/CP
ngy 18/10/1994 v hng dn thi hnh Lut Bo v Mi trng v Ngh nh
26/CP ngy 26/4/1996 v X pht vi phm hnh chnh v bo v mi trng. B
Lut hnh s, hng lot cc thng t, quy nh, quyt nh ca cc ngnh chc nng
v thc hin lut mi trng c ban hnh. Mt s tiu chun mi trng ch
yu c son tho v thng qua. Nhiu kha cnh bo v mi trng c cp
- 8 -
trong cc vn bn khc nh Lut Khong sn, Lut Du kh, Lut Hng hi, Lut
Lao ng, Lut t ai, Lut Pht trin v Bo v rng, Lut Bo v sc kho ca
nhn dn, Php lnh v iu, Php lnh v vic bo v ngun li thu sn, Php
lut bo v cc cng trnh giao thng.
Cc vn bn trn cng vi cc vn bn v lut quc t c nh nc Vit
Nam ph duyt l c s quan trng thc hin cng tc qun l nh nc v bo
v mi trng.
Cng c qun l mi trng l cc bin php hnh ng thc hin cng tc
qun l mi trng ca nh nc, cc t chc khoa hc v sn xut. Mi mt cng
c c mt chc nng v phm vi tc ng nht nh, lin kt v h tr ln nhau.
Cng c qun l mi trng c th phn loi theo chc nng gm: Cng c
iu chnh v m, cng c hnh ng v cng c h tr. Cng c iu chnh v m
l lut php v chnh sch. Cng c hnh ng l cc cng c c tc ng trc tip
ti hot ng kinh t - x hi, nh cc quy nh hnh chnh, quy nh x pht v.v
v cng c kinh t. Cng c hnh ng l v kh quan trng nht ca cc t chc
mi trng trong cng tc bo v mi trng. Thuc v loi ny c cc cng c k
thut nh GIS, m hnh ho, nh gi mi trng, kim ton mi trng, quan trc
mi trng.
Cng c qun l mi trng c th phn loi theo bn cht thnh cc loi c
bn sau:
- Cng c lut php chnh sch bao gm cc vn bn v lut quc t, lut quc
gia, cc vn bn khc di lut, cc k hoch v chnh sch mi trng quc
gia, cc ngnh kinh t, cc a phng.
- Cc cng c kinh t gm cc loi thu, ph nh vo thu nhp bng tin ca hot
ng sn xut kinh doanh. Cc cng c ny ch p dng c hiu qu trong nn
kinh t th trng.
- Cc cng c k thut qun l thc hin vai tr kim sot v gim st nh nc
v cht lng v thnh phn mi trng, v s hnh thnh v phn b cht
nhim trong mi trng. Cc cng c k thut qun l c th gm cc nh gi
- 9 -
mi trng, monitoring mi trng, x l cht thi, ti ch v ti s dng cht
thi. Cc cng c k thut qun l c th c thc hin thnh cng trong bt k
nn kinh t pht trin nh th no.
Ngi ngho lun lun phi chu tc ng nhiu hn bi tnh trng xung
cp v mi trng. 70% dn s Vit Nam kim sng t t ai, iu lm cho h
b ph thuc trc tip vo cht lng v s sn c ca ti nguyn thin nhin. ng
thi, s pht trin nhanh chng v dn s, th ha v kinh t cng to nn sc p
ngy cng tng i vi mi trng v ngi dn, nhng ngi vn phi da vo
mi trng kim sng.
Tnh trng nhim mi trng cng nghip v th thng xuyn vt qu
mc cho php, trong khi bi cc vng th vt qu mc ti a t nht
hai ln.
Bo m s bn vng v mi trng l mt ch tiu quan trng ca Vit
Nam v l mt trong tm Mc tiu Pht trin Thin nin k m Vit Nam cam
kt thc hin n nm 2015. Xt mc rng ln ca ch tiu ny, tht kh c th
o lng. Cc ch s cho thy Vit Nam c th ang trn ng tin ti vic chm
dt tnh trng hy hoi mi trng, nhng cn lu mi c th o ngc c tnh
trng xung cp v mi trng ca thp k va qua.
Chnh ph Vit Nam xy dng c mt khun kh php l tt cho cng
tc qun l mi trng, bt u bng nhng sa i i vi Hin php nm 1992 v
ban hnh Lut Bo v mi trng nm 1994. Gn y B Ti nguyn & mi trng
c thit lp, trong c Cc Mi trng quc gia, Tng cc qun l t ai v
Tng cc Kh tng thy vn.
Chin lc Quc gia v bo v mi trng 2001-2010 ca Vit Nam xc
nh ba mc tiu chung cho chnh sch quc gia v mi trng, l:
- Ngn chn v kim sot tnh trng nhim;
- Bo v, bo tn v s dng bn vng ngun ti nguyn thin nhin;
- Ci thin cht lng mi trng cc khu vc th, cng nghip v nng
thn.
- 10 -
K hoch Hnh ng quc gia v mi trng (2001-2005) c th thm
mt bc bng cch t ra cc u tin v: pht trin bn vng; qun l nc thi v
cht thi rn; qun l rng; tng cng cc nh ch v mi trng; gio dc mi
trng; v s tham gia ca cng ng trong cng tc qun l mi trng. Vic thc
hin k hoch trn y l mt thch thc i vi cc c quan chnh ph, bi h
thng thiu nng lc, cng c v tm nh hng lm cho bo v mi trng tr
thnh mt yu t then cht trong cng tc lp k hoch pht trin kinh t v x hi.
Nhn thy rng qun l mi trng di hn l yu t then cht bo m
pht trin bn vng, chng ta phi s dng cc tri thc chuyn mn, ngun lc v
tuyn truyn vn ng nhm gip ngi dn bo v sc khe v bo tn ngun ti
nguyn thin nhin ca mnh.
L thuyt Qun l mi trng da vo cng ng l mt phng php kh
hon chnh trong qun l mi trng vi hiu qu c chng minh nhiu
quc gia khc nhau. V vy, tip cn v nhn rng m hnh nhiu hn na trong
iu kin nc ta l cn thit mang tnh cp bch nhm hng ti mt x hi pht
trin bn vng.
1.3. K TH
Cc phng php trn c gp li v chia thnh cc cng on:
+ X l cp 1 (Primary treatment).
+ X l cp 2 (Secondary treatment).
+ X l cp 3 (Advanced/ Tertiary treatment).
X l cp 1 gm phng php c hc; x l cp 2 gm phng php ho
hc, ho l hc v sinh hc. X l cp 3 gm s kt hp cc phng php ho hc,
sinh hc kh trit nit, pht pho cn li sau x l cp hai hoc cc cht gy
nhim khc.
x l nc thi, tu theo c im, thnh phn, tnh cht ca nc thi,
cn c cc phng php x l khc nhau (xem hnh 1.1). Trn thc t, ba phng
php sau y thng c ng dng: c hc, ho-l, sinh ho (hoc sinh hc).
- 11 -
loi tr cc vi khun gy bnh trong nc thi cn tin hnh kh trng nc trc
khi x ra sng, h
Nc thi
Bn th cp
Cn s cp
Hnh 1.1. Cc phng php x l nc thi
1.3.1. X l nc thi bng phng php c hc
X l c hc l loi cc tp cht khng ho tan ra khi nc thi bng cch
gn lc, lng v lc. Cc lc trng trng, lc ly tm c p dng tch cc tp
(clo,
- 12 -
cht khng ho tan ra khi nc thi. Phng php x l c hc thng n gin,
r tin, c hiu qu x l cht rn l lng cao. Cc cng trnh, thit b x l c hc
thng dng nh song chn, li chn rc, b lng, b lc
X l c hc tch cn lng trong nc thn rc, cc b
lng ct, lng t I, b lng 2 v, b 2 t hoi, b biogas (trong phm vi h gia nh
- x l ti ch kiu phn tn).
Song chn rc loi cc loi rc v cc tp cht c kch thc ln hn 5
mm, cc tp cht nh hn 5 mm thng ng dng li chn.
B lng ct loi cc tp cht v c v ch yu l ct trong nc thi.
B vt m, du, du m: Cc loi cng trnh ny thng c ng dng khi
x l nc thi cng nghip, nhm loi cc tp cht nh hn nc: m, du m
v tt c cc dng cht ni khc.
B lng loi cc cht l lng c t trng ln, hoc nh hn t trng nc.
B lc loi cc cht trng thi l lng kch thc nh b bng cch lc
chng qua li lc c bit hoc qua lp vt liu lc.
1.3.2. X l nc thi bng phng php ho - l:
y l phng php s dng cc phn ng ho hc x l nc thi. Thc
cht ca phng php ho hc l a vo nc thi cht phn ng no . Cht ny
tc dng vi cc tp cht bn cha trong nc thi v c kh nng loi chng ra
khi nc thi di dng cn lng hoc di dng ho tan khng c hi. Th d
phng php trung ha nc thi cha a xit v kim, phng php o xy ho
Cc qu trnh ha - l s hp khi cc phn t cht bn li vi nhau, chuyn
ha cc hp cht ha tan trong nc thnh cc cht khng tan, c kh nng keo t,
qua tng kch thc v trng lng dn n tng cng kh nng lng ca
chng, (v d: cht kt ta c th s dng loi b phtpho), hoc tiu dit cc vi
khun gy bnh (v d: kh trng bng clo).
Cc cng trnh x l ho hc v ha l thng kt hp vi x l c hc. Cc
phng php ho l thng ng dng x l nc thi l: phng php keo t,
hp ph, trch ly, c bay hi, tuyn ni
- 13 -
Phng php ho hc v ho l c ng dng ch yu x l nc thi
cng nghi c hiu qu x l cao, tuy nhit tin v thng to thnh
cc loi sn phm ph c hi hoc sn phm ph dng rn, bn vng trong mi
trng, kh x l hon ton. Ph thuc vo iu kin a phng v mc cn
thit x l m phng php x l ho hc hay ho l l giai on cui cng (nu
nh mc x l t yu cu c th x nc ra ngun) hoc ch l giai on s b.
1.3.3. X l nc thi bng phng ph
Mc ch ca phng php ny l tch cc hp cht hu c nh hot ng
ca cc vi sinh vt hiu kh hoc ym kh. Thc cht ca phng php sinh ho l
qu trnh khong ho cc cht bn hu c cha trong nc thi dng ho tan, keo
v phn tn nh nh cc qu trnh sinh ho da vo s hot ng ca vi sinh vt c
kh nng tic cht bn hu c cha trong nc thi.
Cc qu trnh x l nc thi sinh hc th hin thng qua cc hot ng ca
h cc vi sinh vt trong nc thi v trong t nhin. Cc vi sinh vt ny s tiu th
v chuyn ha cc tp cht hu c v sn sinh ra cc hp cht n gin hn (v d:
ixit ccbon (CO
2
) v m tan (CH
4
)). Cc vi sinh vt ny pht trin mnh trong cc
mi trng hoc hiu kh, hoc k kh, hoc thiu xy. V d, cc vi sinh vt hiu
kh xy ha cht hu c c cha Nit v Amnic (NH
3
) thnh nitrit (NO
2
#
) v
nitrat (NO
3
#
). Cc vi sinh vt khc c th chuyn ha theo hng k kh - bin
Nitrat thnh Nit (N
2
).
Tu theo cc iu kin lm thong, phng php x lc chia
lm 2 dng:
- Dng th nht gm cc cng trnh m qu trnh lm thong gn nh trong t
nhin: cnh ng ti, cnh ng lc, h sinh vt Trong iu kin kh hu
nc ta, cc cng trnh x l sinh hc t nhin c mt ngha ln. Th nht n
gii quyt vn lm sch nc thi n mc cn thit, th hai n phc v
ti rung, lm mu m t ai v nui c, cui cng, chi ph vn hnh cc cng
trnh ny thng thp hn so vi cc phng php khc.
- 14 -
- Dng th hai gm cc cng trnh lm thong c thc hin trong iu kin
nhn to: b lc sinh hc nh git (biphin nh git), b lc sinh hc cao ti,
arten, h sinh hc lm thong nhn to.
1.3.4. X l nc thi bng phng php tng hp
Ty theo yu cu bo v mi trng nc, bo v sc khe nhn dn, thnh
phn, tnh cht cc loi nc thi cn x l v cc iu kin kinh t- x hi - t
nhin khc m tt c hoc mt phn cc phng php trn c thc hin ng thi
nhm x l trit cc cht gy nhim c trong nc thi vi mc chi ph hp l.
S trn hnh 1.1 l mt v d v x l nc thi (XLNT) bng phng php tng
hp.
: l giai on tiu dit vi khun gy hi trc khi x nc vo
ngun. Cc ho cht dng kh trng nh: hi clo, Hypoclorit-canxi Ca(ClO)2,
nc javen NaClO2, ozon, tia cc tm. y l cng vic tn km nn chng thng
c p dng nhng khu vc c iu kin kinh t pht trin, c th p ng chi
ph xy dng v vn hnh, hay do yu cu cht lng nc c x l mc cao
bo v ngun nc v khu vc nhy cm mi trng.
X nc thi vo ngun tip nhn: Nc thi sinh hot sau khi thu gom
vn chuyn v trm x l khi c x l sinh hc, nc thi c x ra ngun
tip nhn. i vi a bn nghin cu th ngun tip nhn ch yu l cc sng,
mng, ao, h, m v cc cnh ng canh tc nng nghip.
C 3 phng php x nc vo ngun tip nhn:
nc thi vo cnh ng ti: L phng php dng h thng mng t dn
nc thi ra ng rung, cho phn tn nc thi ra nhiu nhnh. Mt phn nc s
bay hi, mt phn ngm vo t to m v cung cp mt phn dinh dng cho
cy trng. Phm vi p dng nhng ni c lng nc thi nh, vng t kh cn
nm xa khu dn c, bc hi cao v t lun thiu m. Cnh ng ti khng
c trng rau xanh v cy thc phm n trc tip v mm bnh v kim loi nng
cha c loi b ht.
- 15 -
nc thi vo ging thm hay bi thm: Dng khi nc thi c lu lng nh,
t c h s thm thch hp, khu vc khng dng ging khi, nc thi khng
cha ho cht c hi. Phng php ny gi l qu trnh lm sch bng thm lc t
nhin trong t.
nc thi vo sng, h, ao, m: y l phng php x nc thi sau khi
x l s b vo vc nc t nhin sn c (h, ao ) hay nhn to, ng vai tr nh
cc h sinh hc x l nc thi. Ti y ngi ta tn dng kh nng t lm sch
ca vc nc t nhin hay nhn to (sng, h), ni xy ra ng thi cc qu trnh:
pha long nc thi vi nc ngun, xy ho cc cht nhim bn hu c ha tan
nh cc vi sinh vt hiu kh (s dng xy ha tan trong nc) tng nc mt v
phn hu k kh (khng c xy) cc cn lng tng di. tng nc gia l cc
nhm vi sinh vt tu tin hot ng. i vi h sinh hc nhn to, chiu su h
thng t 0,5 - 1,5 m. H sinh hc thng c chia lm nhiu ngn (bc). Cc
ngn cui nng hn cc ngn u. C th trng, th cc cy thu sinh (bo, dong,
ng, c nn, sy, lc,…) tng cng hiu qu x l. C th nui c cc ngn
sau ca chui h sinh hc.
Phng php ny c u im l:
- Li dng ao h c sn a phng, khng i hi nhiu vn u t
- Cng tc vn hnh bo dng n gin, khng cn trng nom thng
xuyn
- C th kt hp nui trng thu sn.
Nhc im ca phng php:
Nu lng cht thi (cht hu c, cht dinh dng) qu cao, s lm cho h
sinh vt hiu kh trong h hot ng mnh, ly ht xy ha tan trong nc, dn n
khng ng vt no sng ni. Mt khc, to s pht trin mnh khi h b ph dng.
n khi ht ngun dinh dng th cc h sinh vt, c bit l to b cht hng lot,
khi nc h s b nhim nng, gy mi hi thi (h cht).
X l b
n, cn ca nc thi: Trong qu trnh x l nc thi, bng bt k
phng php no cng to nn mt lng cn ng k. Cc cht khng ho tan b
- 16 -
lng t I c gi l cn ti. Cn cn lng sau giai on x l sinh hc c gi
l mng vi sinh (nu dng biphin) v bn hot tnh (nu dng arten), cn lng
sau cc cng trnh x l sinh hc hay b gi li b lng t II. Ni chung, cc loi
cn trn u c mi hi thi kh chu (nht l cn ti) v l s biu hin trng
thi nguy him v phng din v sinh. Do vy m cn nht thit phi c x l
thch ng. gim hm lng cc cht hu c trong cn v t c cc ch
tiu v mt v sinh trong thc t ngi ta thng ng dng phng php x l sinh
hc ym kh trong cc cng trnh tng ng: b t hoi, b lng hai v v b mtan.
u im ca phng php x l sinh hc l tn dng c iu kin t
nhin, gim chi ph nng lng v ha cht, n gin v r tin hn so vi phng
php ha - l v c kh nng tn dng cc sn phm ph nh thu hi kh t v bn
lm phn bn.
y cc b x l sinh hc hay cc b lng nc thi c cc cht khng ha
tan nh rc, lng cn sn phm ca qu trnh xy ho ch yu l ct, thnh phn v
c, t trng ln c nh k vt ln phi kh san nn hoc ch bin thnh phn
bn, cc loi rc c vt ln a v bi chn lp rc thi. Cc loi cn lng cn
h ga gia nh, nht l sau cc chung tri, c hm lng hu c cao, c th vt ln
vi bn trong b x l sinh hc lm phn vi sinh.
1.4. T
1.4.1. S cn thit ca vic ti s dng nc thi:
Hng ngy, cc thnh ph, th x ln nh u x ra ngoi thnh mt lng
ln nc thi, bao gm nc thi cng nghip v nc thi sinh hot. Trong ngun
nc thi c cha nhiu nguyn t dinh dng nh nit, phtpho, rt cn cho
cy trng. Lu nay mt s nc trn th gii dng ngun nc thi t thnh ph
trc tip ti cho ng rung v t c kt qa rt khc nhau, c ni sn lng
lng thc, hoa mu tng hn ln, nhng c ni b tht thu nghim trng,
Cc nh khoa hc t lu cnh bo khng c dng nc thi ca thnh
ph trc tip ti rung. Bi v trong ngun nc thi c cha rt nhiu nguyn
- 17 -
t kim loi nng c hi cho c th con ngi nh caimi, km, ch, thu ngn, v
c cc cht hu c c hi kh phn hy, cc loi vi trng gy bnh, v.v Nhng
cht c hi trn u trc tip gy nhim cho cy lng thc, rau qu v s li
hu qu nghim trng cho con ngi nu n phi.
Tt nhin khng v vy m chng ta b ph ngun nc thi ca thnh ph.
Ngi ra tn dng ngun nc thi v tn ca thnh ph bng cch kh cc
nguyn t kim loi nng, cc cht hu c c hi v cc loi vi trng gy bnh, sau
mi ti cho ng rung. Nc thi thnh ph c x l ti cho cy trng
khng nhng khng lm nhim lng thc, rau qu m cn lm tng sn lng
cc loi cy trng, ng thi lc sch thm ngun nc thi, gim bt nhim sng
h. y l phng php s dng nc thi khoa hc nht v ang c nhiu nc
thc hin.
Nc thi sinh hot cha hm lng ln Nit, Phtpho, Kali l nhng cht
cn thit cho cy trng. V vy xu th s dng nc thi ti cy v bn cn ca
n lm phn bn ngy cng tng.
Nc thi sau khi lng s b c th s dng ti cho cy trng. Cng
tc vo c im t, cy trng v nng cc cht trong nc thi v
dao ng t 0,1 n 0,2 m/m
2
/nm (1.000m
3
/ha n 2.000m
3
/ha/nm ) v sn lng
cy trng s tng thm 20% n 30%.
Qu trnh x l nc thi sinh hot s to nn lng ln bn cn (bng
khong 1% th tch nc thi x l). Bn cn nc thi cha phn ln cc cht hu
c, nit v phtpho. Hm lng kali tng i thp nn ngi ta thng b sung
thm kali trn cng bn cn lm phn bn. Ngoi ra hm lng CaO trong bn
cn cao nn n thch hp trong vic ci to t chua phn.
Trong nc thi v bn cn ca n c cha cc loi vi khun gy bnh, trng
giun sn. Trong 1 gam bn cn cha t 5 n 67 trng giun sn. Trng giun sn c
th tn ti trong t n 1,5 nm, v vy nn hn ch ti nc thi trong ma thu
hoch. i vi cc loi rau n sng th khng c ti trc tip nc thi ln cy
rau.
- 18 -
Hu ht cc th v khu cng nghip Vit Nam u c xy dng t rt
lu v khng c h thng x l nc thi, h thng tiu thot nc thi c k, km
tc dng. Nc thi ca cc th v khu cng nghip c x trc tip vo cc ao
h, h thng thu nng ca cc vng ph cn. Nhng nm 90 tr v trc, mc
nhim cha nhiu nn s dng nc thi c coi l ngun li i vi ngi sn
xut. Do nhu cu pht trin, tc th ho ngy cng tng nhanh, cc khu cng
nghip ngy cng m rng th nhim do nc thi th v khu cng nghip ngy
cng trm trng, nhiu ni mc bo ng, nh hng n mi trng, sc
kho cng ng v s pht trin ca cc ngnh kinh t.
1.4.2. Tng quan v tnh hnh ti s dng nc thi trn th gii
T u th k 19, Anh v Cng ho Lin bang c xy dng nhng
cnh ng chuyn ti nc thi, trc c x l c hc. Sang u th k th 20,
tng din tch ti bng nc thi ch tnh ring Chu u ln n 80-90 ngn
ha, trong trung bnh mi ngy s dng 40-100m
3
nc thi cho mi ha.
Evilevit (1995) cho rng nng sut ca cy trng s tng ng k nu c phn
loi phn bn v c b sung cho lng cn thi khi bn rung vi liu lng ca
Nit l 30 - 40 kg/ha, vi v Kali l 60kg/ha. Tuy vy, yu t ht sc quan trng
tng nng sut cy trng l liu lng cn thi s dng bn rung. Tc gi ch
r nng ca cc nguyn t dinh dng N, P, K trong nc thi tu thuc vo tiu
chun thot nc cng nh tnh cht ca nc thi. Tuy vy, cy trng cng ch s
dng mt phn cc cht dinh dng ny trong nc thi. Do , vic nghin cu
cng ngh ti hp l bng nc thi l rt cn thit m bo tn dng phn bn
trong nc thi.
Ti Ba Lan, cc nghin cu v vic s dng nc thi cho mc ch nng
nghip c thc hin ti cc c s (x nghip) sn xut tinh bt. Lng nc
thi ny c thi ra cnh ng v kt qu cho thy l lng BOD v COD gim
xung r rt trong c h thng mng mng, c th l khong 97% v 98%, v h
thng knh ln 96.5% n 95%. Trong khu vc t canh tc, cn phi quan tm
trnh vic s dng nc thi c nhiu tinh bt ti
- 19 -
Theo Wimvander Hoek (2001), ti s dng nc thi trong nng nghip c
th mang li rt nhiu li ch: tit kim nc, tn dng c ni cha nc thi vi
gi thnh r, gim nhim nc sng v nc mt, tn dng c ngun dinh
dng trong nc thi dn n tit kim phn bn, tng sn lng cy trng Tuy
nhin, bn cnh cc mt tch cc cng c rt nhiu mt tiu cc nu ti s dng
nc thi khng hp l: gy nh hng n sc kho ngi nng dn lm cng vic
ti v nhng ngi tiu th sn phm, gy nhim ngun nc ngm, c bit l
bi nitrat, tch lu nhim cc cht ho hc, c bit l kim loi nng trong t, to
iu kin cho cc sinh vt truyn bnh nh mui pht trin.
Smith (1994) cho rng vic s dng bn thi lm phn bn trong nng
nghip em li li ch v kinh t v mi trng. Khi t c bn bn thi c th
b tch lu kim loi nng nh: Cd, Cu, Pb v Zn.
Chang v cng tc vin (1987) nghin cu v cho thy bn bn thi cha
cc kim loi nng c th c tch lu trong sn phm trng trt v l nguyn nhn
gy hi cho ngi tiu dng.
Van Den Berg (1993) cho rng khi s dng bn thi lm phn bn cn phi
nghin cu k v n c th lm tng mt s bnh l ca cy trng v lm nhim
ho hc.
1.4.3. Tng quan v tnh hnh ti s dng nc thi Vit Nam
Dai Peters v c Ngi lm th nghim dng nc thi ca lng ngh
ch bin tinh bt dong, sn x Dng Liu v x Minh Khai ti la cho kt qu
nh sau: dng 80% nc thi ti cho nng sut la cao nht so vi cc t l
dng nc thi khc; dng nc thi ti trong 6 tun u c nng sut cao hn
6 tun cui ca thi v gieo trng; dng nc thi ti 1 ln/tun cho nng sut cao
hn ti thng xuyn; v dng nc thi cha x l cho nng sut cao hn dng
nc thi qua lng. Th nghim cng cho thy i vi la c ti bng nc
thi c cy vi mt cao (60 gc/m
2
) cho nng sut cao nht (so vi 35 hay 40
gc/m
2
).