do an xu ly nuoc thai nha may che bien thuy san 504

8/2/2019 Do an Xu Ly Nuoc Thai Nha May Che Bien Thuy San 504

1/77

PHN 1: TNG QUAN

1.1. Tnh cp thit ca ti

Ngnh cng nghip ch bin thy hi sn v ang em li nhng

li nhun khng nh cho nn kinh t Vit Nam ni chung v ca ngi

nng dn nui trng thy hi sn ni ring. Nhng bn cnh nhng li ch

m n mang li nh gim i ngho, tng trng GDP cho quc gia th n

cng li nhng hu qu tht kh lng i vi mi trng sng ca

chng ta. Hu qu l cc con sng, knh rch nc b en bn v bc mi

hi thi mt phn l do vic sn xut v ch bin thy hi sn thi ra mt

lng ln nc thi c mi hi tanh vo mi trng m khng qua bt k

giai on x l no. Chnh iu ny gy nh hng rt ln i vi con

ngi v h sinh thi gn cc khu vc c lng nc thi ny thi ra.

ng trc nhng i hi v mt mi trng sng trong lnh ca

ngi dn, cng nh qui nh v vic sn xut i vi cc doanh nghip khi

nc ta gia nhp WTO i hi mi mt n v sn xut kinh doanh phi

cn c mt h thng x l nc thi nhm gim thiu nh hng n mi

trng xung quanh. ng trc nhng i hi cp bch , nhm ting

hnh nghin cu tnh ton thit k h thng x l nc thi ca cc nh

my sn xut v ch bin thy hi sn.

1.2. Mc ch

X l nc thi nh my A ang xt hot ng ch bin thy hi

sn lu lng trung bnh l 1000 m3/ngy m, vi cc thng s u vo

bng 1 t TCVN 5945 2005 ct B c th thi vo ngun tip nhn.

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Ch tiu Hm lngTCVN 5945

-2005 (ct B)n v

Thi gian thi 24 hLu lng

trung bnh 1000 M3/ngy m

pH 6.9 7.9 5.5 9COD 1500 100 Mg/lBOD 1050 50 Mg/lSS 270 100 Mg/l

N tng 120 60 Mg/lP tng 10 6 Mg/l

Bng 1.1: Phn tch ch tiu phn tch

1.3. Phng php nghin cu

Phng php phn tch, x l s liu.

Phng php quan st.

Phng php su tm, thng k s liu.

PHN 2: NGUN GC PHT SINH, THNH

PHN V TC NG MI TRNG CA

2


3/77

CC CHT NHIM TRONG NGNH CH

BIN THY HI SN

2.1. Ngun gc pht sinh cc cht nhim trong ngnh ch bin

thy hi sn.

Ty thuc vo cc loi nguyn liu nh tm, c, s, mc, cua m

cng ngh s c nhiu im ring bit. tuy nhin quy trnh sn xut c cc

dng sau:

Quy trnh cng ngh sn xut cc sn phm kh ca cng ty Seapimex

(Ngun Phan Thu nga lun vn cao hc 1997)

3

Nc thi

Nguyn liu th

S ch (chi schct, cht u, ltd, b sng)

Nng

ng gi

Bo qun lnh

(-180

C)

Cn, x mng

COD = 100 800mg/LSS = 30 100mg/L

Ntc = 17 - 31mg/L

Phn c, loi

ng gi

Bo qun lnh(-180C)


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Quy trnh cng ngh sn xut cc sn phm ng lnh

ca cng ty Seapimex


Nc thi

Ra

Nguyn liu ti pc

Ra

S ch

Phn c,loi

Xp khun

ng lnh

ng gi

Bo qun lnh(-250C -180C)

SS : 128 280 mg/LCOD :400 2.200 mg/L

Ntc

: 57 126 mg/L

Ptc

: 23 98 mg/L

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Quy trnh cng ngh sn xut cc sn phm ng hp ca cng ty

Seapimex


Nc thi

Nguyn liu (tm, tht chn p lnh)

Ra

Loi b tp cht

Luc s b

ng vo hp

Cho nc mui vo

Ghp m hp

Kh trng

ngui

Dn nhn

ng gi

Bo qun

SS : 150 250 mg/L

COD : 336 1000 mg/LN

tc: 42 127 mg/L

Ptc

: 37 125 mg/L

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6/77

2.2. Thnh phn v tnh cht nc thi thy hi sn.

Vi cc quy trnh cng ngh nh trn th ngun pht sinh

cht thi gy nhim ch yu trong cc cng ty ch bin ng lnh th

c chia lm ba dng: cht thi rn, cht thi lng v cht thi kh. Trong

qu trnh sn xut cn gy ra cc ngun nhim khc nh ting n,

rung v kh nng gy chy n.

Cht thi rn

Cht thi rn thu c t qu trnh ch bin tm, mc, c, s c u

v tm, v s, da, mai mc, ni tng Thnh phn chnh ca ph thi sn

xut cc sn phm thu sn ch yu l cc cht hu c giu m, canxi,phtpho. Ton b ph liu ny c tn dng ch bin cc sn phm

ph, hoc em bn cho dn lm thc n cho ngi, thc n chn nui gia

sc, gia cm hoc thu sn.

Ngoi ra cn c mt lng nh rc thi sinh hot, cc bao b, dy

ning h hng hoc qua s dng vi thnh phn c trng ca rc thi

th.Cht thi lng

Nc thi trong cng ty my ch bin ng lnh phn ln l nc

thi trong qu trnh sn xut bao gm nc ra nguyn liu, bn thnh

phm, nc s dng cho v sinh v nh xng, thit b, dng c ch bin,

nc v sinh cho cng nhn.

Lng nc thi v ngun gy nhim chnh l do nc thi trongsn xut.

Cht thi kh

Kh thi sinh ra t cng ty c th l:

- Kh thi Chlor sinh ra trong qu trnh kh trng thit b, nh

xng ch bin v kh trng nguyn liu, bn thnh phm.

- Mi tanh t mc, tm nguyn liu, mi hi tanh t ni cha ph

thi, v s, cng rnh.

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- Hi tc nhn lnh c th b r r: NH3

- Ting n xut hin trong cng ty ch bin thu sn ch yu do

hot ng ca cc thit b lnh, chy n, phng tin vn chuyn

- Trong phn xng ch bin ca cc cng ty thu sn nhit

thng thp v m hn so khu vc khc.

2.3. Tc ng ca nc thi ch bin thy hi sn n mi

trng.

Nc thi ch bin thu sn c hm lng cc cht nhim cao nu

khng c x l s gy nhim cc ngun nc mt v nc ngm trong

khu vc.i vi nc ngm tng nng, nc thi ch bin thu sn c th

thm xung t v gy nhim nc ngm. Cc ngun nc ngm nhim

cc cht hu c, dinh dng v vi trng rt kh x l thnh nc sch cung

cp cho sinh hot.

i vi cc ngun nc mt, cc cht nhim c trong nc thi

ch bin thu sn s lm suy thoi cht lng nc, tc ng xu n mitrng v thy sinh vt, c th nh sau:

Cc cht hu c

Cc cht hu c cha trong nc thi ch bin thu sn ch yu l

d b phn hy. Trong nc thi cha cc cht nh cacbonhydrat, protein,

cht bo... khi x vo ngun nc s lm suy gim nng oxy ha tan

trong nc do vi sinh vt s dng xy ha tan phn hy cc cht hu c.Nng oxy ha tan di 50% bo ha c kh nng gy nh hng ti s

pht trin ca tm, c. Oxy ha tan gim khng ch gy suy thoi ti

nguyn thy sn m cn lm gim kh nng t lm sch ca ngun nc,

dn n gim cht lng nc cp cho sinh hot v cng nghip.

Cht rn l lng

Cc cht rn l lng lm cho nc c hoc c mu, n hn ch

su tng nc c nh sng chiu xung, gy nh hng ti qu trnh

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quang hp ca to, rong ru... Cht rn l lng cng l tc nhn gy nh

hng tiu cc n ti nguyn thy sinh ng thi gy tc hi v mt cm

quan (tng c ngun nc) v gy bi lng lng sng, cn tr s lu

thng nc v tu b

Cht dinh dng (N, P)

Nng cc cht nit, photpho cao gy ra hin tng pht trin

bng n cc loi to, n mc gii hn to s b cht v phn hy gy

nn hin tng thiu oxy. Nu nng oxy gim ti 0 gy ra hin tng

thy vc cht nh hng ti cht lng nc ca thy vc. Ngoi ra, cc

loi to ni trn mt nc to thnh lp mng khin cho bn di khng cnh sng. Qu trnh quang hp ca cc thc vt tng di b ngng tr. Tt

c cc hin tng trn gy tc ng xu ti cht lng nc, nh hng ti

h thu sinh, ngh nui trng thu sn, du lch v cp nc.

Amonia rt c cho tm, c d nng rt nh. Nng lm cht

tm, c, t 1,2 3 mg/l. Tiu chun cht lng nc nui trng thy sn

ca nhiu quc gia yu cu nng Amonia khng vt qu 1mg/l.Vi sinh vt

Cc vi sinh vt c bit vi khun gy bnh v trng giun sn trong

ngun nc l ngun nhim c bit. Con ngi trc tip s dng ngun

nc nhim bn hay qua cc nhn t ly bnh s truyn dn cc bnh dch

cho ngi nh bnh l, thng hn, bi lit, nhim khun ng tit niu,

tiu chy cp tnh.

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9/77

PHN 3: TNG QUAN V

C S L THUYT

3.1. Phng php x l c hc.

Phng php x l c hc s dng nhm mc ch tch cc cht khng

ha tan v mt phn cc cht dng keo ra khi nc thi .Nhng cng

trnh x l c hc bao gm :

3.1.1. Song chn rc

Song chn rc nhm chn gi cc cn bn c kch thc ln hay

dng si: giy, rau c, rc c gi chung l rc. Rc c chuyn ti

my nghin nghin nh, sau c chuyn ti b phn hy cn (b

mtan). i vi cc tp cht < 5 mm thng dng li chn rc. Cu to

ca thanh chn rc gm cc thanh kim loi tit din hnh ch nht, hnh

trn hoc bu dc Song chn rc c chia lm 2 loi di ng hoc c

nh, c th thu gom rc bng th cng hoc c kh. Song chn rc c

t nghing mt gc 60 90 0 theo hng dng chy.

3.1.2. B lng ct

B lng ct dng tch cc cht bn v c c trng lng ring

ln hn nhiu so vi trng lng ring ca nc nh x than, ct ra

khi nc th. Ct t b lng ct c a i phi kh sn phi v ct

kh thng c s dng li cho nhng mc ch xy dng.3.1.3. B lng

B lng dng tch cc cht l lng c trng lng ring ln hn

trng lng ring ca nc. Cht l lng nng hn s t t lng xung y,

cn cht l lng nh hn s ni ln mt nc hoc tip tc theo dng nc

n cng trnh x l tip theo. Dng nhng thit b thu gom v vn chuyn

cc cht bn lng v ni (ta gi l cn ) ti cng trnh x l cn .

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Da vo chc nng, v tr c th chia b lng thnh cc

loi: b lng t 1 trc cng trnh x l sinh hc v b lng t 2 sau cng

trnh x l sinh hc.

Da vo nguyn tc hot ng, ngi ta c th chia ra cc

loi b lng nh: b lng hot ng gin on hoc b lng hot ng lin

tc.

Da vo cu to c th chia b lng thnh cc loi nh sau:

b lng ng, b lng ngang, b lng ly tm v mt s b lng khc.

3.1.3.1. B lng ng

B lng ng c dng hnh trn hoc hnh ch nht trn mt bng.B lng ng thng dng cho cc trm x l c cng sut di 20.000

m3/ngym. Nc thi c dn vo ng trung tm v chuyn ng t

di ln theo phng thng ng. Vn tc dng nc chuyn ng ln phi

nh hn vn tc ca cc ht lng. Nc trong c tp trung vo mng thu

pha trn. Cn lng c cha phn hnh nn hoc chp ct pha di.

3.1.3.2. B lng ngangB lng ngang c hnh dng ch nht trn mt bng, t l gia chiu

rng v chiu di khng nh hn v chiu su n 4m. B lng ngang

dng cho cc trm x l c cng sut ln hn 15.000 m3/ ngym. Trong

b lng nc thi chuyn ng theo phng ngang t u b n cui b v

c dn ti cc cng trnh x l tip theo, vn tc dng chy trong vng

cng tc ca b khng c vt qu 40 mm/s. B lng ngang c h thu

cn u b v nc trong c thu vo mng cui b.

3.1.3.3. B lng ly tm

B lng ly tm c dng hnh trn trn mt bng. B lng ly tm

c dng cho cc trm x l c cng sut ln hn 20.000 m3/ngym.

Trong b lng nc chy t trung tm ra quanh thnh b. Cn lng c

dn vo h thu cn c xy dng trung tm y b bng h thng co

gom cn phn di dn quay hp vi trc 1 gc 450. y b thng c

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thit k vi dc i = 0,02 0,05. Dn quay vi tc 2-3 vng trong 1

gi. Nc trong c thu vo mng t dc theo thnh b pha trn.

3.1.4. B vt du m

B vt du m thng c p dng khi x l nc thi c cha

du m (nc thi cng ngip), nhm tch cc tp cht nh. i vi thi

sinh hot khi hm lng du m khng cao th vic vt du m thc hin

ngay b lng nh thit b gt cht ni.

3.1.5. B lc

B lc nhm tch cc cht trng thi l lng kch thc nh bng

cch cho nc thi i qua lp lc c bit hoc qua lp vt liu lc. B nyc s dng ch yu cho mt s loi nc thi cng nghip. Qu trnh

phn ring c thc hin nh vch ngn xp, n cho nc i qua v gi

pha phn tn li. Qu trnh din ra di tc dng ca p sut ct nc.

Hiu qu ca phng php x l c hc

C th loi b c n 60% tp cht khng ho tan c trong nc

thi v gim BOD n 30%. tng hiu sut cng tc ca cc cng trnhx l c hc c th dng bin php lm thong s b, thong gi ng t

sinh hc, hiu qu x l c th t ti 75% theo hm lng cht l lng v

40-50 % theo BOD.

Trong s cc cng trnh x l c hc c th k n b t hoi, b

lng hai v, b lng trong c ngn phn hu l nhng cng trnh va

lng va phn hu cn lng.

3.2. Phng php x l ha l.

Bn cht ca qu trnh x l nc thi bng phng php ho l l

p dng cc qu trnh vt l v ho hc a vo nc thi cht phn ng

no gy tc ng vi cc tp cht bn, bin i ho hc, to thnh

cc cht khc di dng cn hoc cht ho tan nhng khng c hi hoc

gy nhim mi trng. Giai on x l ho l c th l giai on x l

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c lp hoc x l cng vi cc phng php c hc, ho hc, sinh hc

trong cng ngh x l nc thi hon chnh.

Nhng phng php ho l thng c p dng x l nc thi

l : keo t, ng t, tuyn ni, hp ph, trao i ion, thm lc ngc v siu

lc

3.2.1. Phng php keo t v ng t

Qu trnh lng ch c th tch c cc ht rn huyn ph nhng

khng th tch c cc cht gy nhim bn dng keo v ha tan v

chng l nhng ht rn c kch thc qu nh. tch cc ht rn mt

cch c hiu qu bng phng php lng, cn tng kch thc ca chngnh s tc ng tng h gia cc ht phn tn lin kt thnh tp hp cc

ht, nhm tng vn tc lng ca chng. Vic kh cc ht keo rn bng lng

trng lng i hi trc ht cn trung ha in tch ca chng, th n l

lin kt chng vi nhau. Qu trnh trung ho in tch thng c gi l

qu trnh ng t (coagulation), cn qu trnh to thnh cc bng ln hn

t cc ht nh gi l qu trnh keo t (flocculation).3.2.1.1. Phng php keo t

Keo t l qu trnh kt hp cc ht l lng khi cho cc cht cao

phn t vo nc. Khc vi qu trnh ng t, khi keo t th s kt hp

din ra khng ch do tip xc trc tip m cn do tng tc ln nhau gia

cc phn t cht keo t b hp ph trn cc ht l lng .

Cht keo t thng dng c th l hp cht t nhin v tng hp

cht keo t nhin l tinh bt, ete, xenluloz, dectrin (C6H10O5)n v dioxyt

silic hot tnh (xSiO2.yH2O).

3.2.1.2 Phng php ng t

Qu trnh thu phn cc cht ng t v to thnh cc bng keo xy

ra theo cc giai on sau :

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Me3+ + HOH Me(OH)2+ + H+

Me(OH)2+ + HOH Me(OH)+ + H+

Me(OH)+ + HOH Me(OH)3 + H+

Me3+ + 3HOH Me(OH)3 + 3 H+

Cht ng t thng dng l mui nhm, st hoc hoc hn hp

ca chng. Vic chn cht ng t ph thuc vo thnh phn, tnh cht ho

l, gi thnh, nng tp cht trong nc, pH .

Cc mui nhm c dng lm cht ng t: Al2(SO4)3.18H2O,NaAlO2, Al(OH)2Cl, Kal(SO4)2.12H2O, NH4Al(SO4)2.12H2O. Thng

sunfat nhm lm cht ng t v hot ng hiu qu pH = 5 7.5, tan tt

trong nc, s dng dng kh hoc dng dung dch 50% v gi thnh

tng i r.

Cc mui st c dng lm cht ng t: Fe(SO3).2H2O,

Fe(SO4)3.3H2O, FeSO4.7H2O v FeCl3. Hiu qu lng cao khi s dngdng kh hay dung dch 10 -15%.

3.2.2. Tuyn ni

Phng php tuyn ni thng c s dng tch cc tp cht (

dng rn hoc lng) phn tn khng tan, t lng km ra khi pha lng.

Trong x l nc thi, tuyn ni thng c s dng kh cc cht l

lng v lm c bn sinh hc. u im c bn ca phng php ny so vi

phng php lng l c th kh c hon ton cc ht nh hoc nh, lng

chm, trong mt thi gian ngn. Khi cc ht ni ln b mt, chng c

th thu gom bng b phn vt bt.

Qu trnh tuyn ni c thc hin bng cch sc cc bt kh nh

(thng l khng kh ) vo trong pha lng. Cc kh kt dnh vi cc ht

v khi lc ni ca tp hp cc bng kh v ht ln s ko theo ht cng

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ni ln b mt, sau chng tp hp li vi nhau thnh cc lp bt cha

hm lng cc ht cao hn trong cht lng ban u .

3.2.3. Hp ph

Phng php hp ph c dng rng ri lm sch trit nc

thi khi cc cht hu c ho tan sau khi x l sinh hc cng nh x l cc

b khi nc thi c cha mt hm lng rt nh cc cht . Nhng cht

ny khng phn hu bng con ng sinh hc v thng c c tnh cao.

Nu cc cht cn kh b hp ph tt v chi ph ring cho lng cht hp

ph khng ln th vic ng dng phng php ny l hp l hn c.

Cc cht hp ph thng c s dng nh: than hot tnh, cc chttng hp v cht thi ca vi ngnh sn xut c dng lm cht hp ph

(tro, r, mt ca ). Cht hp ph v c nh t st, silicagen, keo nhm

v cc cht hydroxit kim loi t c s dng v nng lng tng tc ca

chng vi cc phn t nc ln. Cht hp ph ph bin nht l than hot

tnh, nhng chng cn c cc tnh cht xc nh nh : tng tc yu vi cc

phn t nc v mnh vi cc cht hu c, c l xp th c th hp phcc phn t hu c ln v phc tp, c kh nng phc hi. Ngoi ra, than

phi bn vi nc v thm nc nhanh. Quan trng l than phi c hot

tnh xc tc thp i vi phn ng oxy ha bi v mt s cht hu c trong

nc thi c kh nng b oxy ho v b ho nha. Cc cht ho nha bt kn

l xp ca than v cn tr vic ti sinh n nhit thp.

3.2.4. Phng php trao i ion

Trao i ion l mt qu trnh trong cc ion trn b mt ca cht

rn trao i vi ion c cng in tch trong dung dch khi tip xc vi nhau.

Cc cht ny gi l cc ionit (cht trao i ion), chng hon ton khng tan

trong nc.

Cc cht c kh nng ht cc ion dng t dung dch in ly gi l

cationit, nhng cht ny mang tnh axit. Cc cht c kh nng ht cc ion

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m gi l anionit v chng mang tnh kim. Nu nh cc ionit no trao

i c cation v anion gi l cc ionit lng tnh.

Phng php trao i ion thng c ng dng loi ra khi

nc cc kim loi nh: Zn, Cu, Cr, Ni, Pb, Hg, M ,vv, cc hp cht

ca Asen, photpho, Cyanua v cc cht phng x.

Cc cht trao i ion l cc cht v c hoc hu c c ngun gc t

nhin hay tng hp nhn to. Cc cht trao i ion v c t nhin gm c

cc zeolit, kim loi khong cht, t st, fenspat, cht mica khc nhau

v c tng hp gm silicagen, pecmutit (cht lm mm nc ), cc oxyt

kh tan v hydroxyt ca mt s kim loi nh nhm, crm, ziriconi Cccht trao i ion hu c c ngun gc t nhin gm axit humic v than

chng mang tnh axit, cc cht c ngun gc tng hp l cc nha c b

mt ring ln l nhng hp cht cao phn t.

3.2.5. Cc qu trnh tch bng mng

Mng c nh ngha l mt pha ng vai tr ngn cch gia cc

pha khc nhau .Vic ng dng mng tch cc cht ph thuc vo thm ca cc hp cht qua mng. Ngi ta dng cc k thut nh: in

thm tch, thm thu ngc, siu lc v cc qu trnh tng t khc.

Thm thu ngc v siu lc l qu trnh lc dung dch qua mng

bn thm thu, di p sut cao hn p sut thm lc. Mng lc cho cc

phn t dung mi i qua v gi li cc cht ho tan. S khc bit gia hai

qu trnh l ch siu lc thng c s dng tch dung dch c khi

lng phn t trn 500 v c p sut thm thu nh (v d nh cc vi

khun, tinh bt, protein, t st ). Cn thm thu ngc thng c s

dng kh cc vt liu c khi lng phn t thp v c p sut cao.

3.2.6. Phng php in ho

Mc ch ca phng php ny l x l cc tp cht tan v phn tn

trong nc thi, c th p dng trong qu trnh oxy ho dng cc, kh m

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cc, ng t in v in thm tch. Tt c cc qu trnh ny u xy ra

trn cc in cc khi cho dng in 1 chiu i qua nc thi.

Nhc im ln ca phng php ny l tiu hao in nng ln.

3.3. Phng php x l sinh hc.

Phng php x l sinh hc l s dng kh nng sng, hot ng

ca vi sinh vt phn hu cc cht bn hu c c trong nc thi. Cc vi

sinh vt s dng cc hp cht hu c v mt s khong cht lm ngun

dinh dng v to nng lng. Trong qu trnh dinh dng, chng nhn

cc cht dinh dng xy dng t bo, sinh trng v sinh sn v th sinh

khi ca chng c tng ln . Qu trnh phn hy cc cht hu c nh visinh vt gi l qu trnh oxy ha sinh ha. Phng php x l sinh hc c

th thc hin trong iu kin hiu kh ( vi s c mt ca oxy) hoc trong

iu kin k kh( khng c oxy).

Phng php x l sinh hc c th ng dng lm sch hon ton

cc loi nc thi cha cht hu c ho tan hoc phn tn nh. Do vy

phng php ny thng c p dng sau khi loi b cc loi tp cht thra khi nc thi c hm lng cht hu c cao.

Qu trnh x l sinh hc gm cc bc

Chuyn ho cc hp cht c ngun gc cacbon dng

keo v dng ho tan thnh th kh v thnh cc v t bo vi sinh.

To ra cc bng cn sinh hc gm cc t bo vi sinh

vt v cc cht keo v c trong nc thi

Loi cc bng cn ra khi nc thi bng qu trnh lng

3.3.1 X l nc thi bng phng php sinh hc trong iu

kin t nhin.

tch cc cht bn hu c dng keo v ho tan trong iu kin t

nhin ngi ta x l nc thi trong ao, h ( h sinh vt) hay trn t ( cnh

ng ti, cnh ng lc).

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17/77

3.3.1.1. H sinh vt

H sinh vt l cc ao h c ngun gc t nhin hoc nhn to, cn

gi l h oxy ho, h n nh nc thi, x l nc thi bng phng

php sinh hc. Trong h sinh vt din ra qu trnh oxy ha sinh ha cc

cht hu c nh cc loi vi khun, to v cc loi thy sinh vt khc, tng

t nh qu trnh lm sch ngun nc mt. Vi sinh vt s dng oxy sinh ra

t ru to trong qu trnh quang hp cng nh oxy t khng kh oxy ho

cc cht hu c, rong to li tiu th CO2, photphat v nitrat amon sinh ra

t s phn hu, oxy ho cc cht hu c bi vi sinh vt. h hot ng

bnh thng cn phi gi gi tr pH v nhit ti u. Nhit khngc thp hn 60C.

Theo bn cht qu trnh sinh ho, ngi ta chia h sinh vt ra cc

loi h hiu kh, h sinh vt tu tin (Faculative) v h sinh vt ym kh.

H sinh vt hiu kh

Qu trnh x l nc thi xy ra trong iu kin y oxy, oxy

c cung cp qua mt thong v nh quang hp ca to hoc h c lmthong cng bc nh cc h thng thit b cp kh. su ca h sinh vt

hiu kh khng ln t 0,5-1,5m.

H sinh vt tu tin

C su t 1.5 2.5m, trong h sinh vt ty tin, theo chiu su

lp nc c th din ra hai qu trnh: oxy ho hiu kh v ln men ym kh

cc cht bn hu c. Trong h sinh vt ty tin vi khun v to c quan htng h ng vai tr c bn i vi s chuyn ha cc cht.

H sinh vt ym kh

C su trn 3m, vi s tham gia ca hng trm chng loi vi

khun k kh bt buc v k kh khng bt buc. Cc vi sinh vt ny tin

hnh hng chc phn ng ho sinh hc phn hu v bin i cc hp

cht hu c phc tp thnh nhng cht n gin, d x l. Hiu sut gimBOD trong h c th ln n 70%. Tuy nhin nc thi sau khi ra khi h

17


18/77

vn c BOD cao nn loi h ny ch ch yu p dng cho x l nc thi

cng nghip rt m c v dng lm h bc 1 trong t hp nhiu bc.

3.3.1.2. Cnh ng ti - Cnh ng lc

Cnh ng ti l nhng khong t canh tc, c th tip nhn v x

l nc thi. X l trong iu kin ny din ra di tc dng ca vi sinh

vt, nh sng mt tri, khng kh v di nh hng ca cc hot ng

sng thc vt, cht thi b hp th v gi li trong t, sau cc loi vi

khun c sn trong t s phn hu chng thnh cc cht n gin cy

trng hp th. Nc thi sau khi ngm vo t, mt phn c cy trng s

dng. Phn cn li chy vo h thng tiu nc ra sng hoc b sung chonc ngun.

3.3.2. X l nc thi bng phng php sinh hc trong iu

kin nhn to

3.3.2.1. B lc sinh hc

B lc sinh hc l cng trnh nhn to, trong nc thi c lc

qua vt liu rn c bao bc mt lp mng vi sinh vt. B lc sinh hc gmcc phn chnh nh sau: phn cha vt liu lc, h thng phn phi nc

m bo ti u ln ton b b mt b, h thng thu v dn nc sau khi

lc, h thng phn phi kh cho b lc.

Qu trnh oxy ha cht thi trong b lc sinh hc din ra ging nh

trn cnh ng lc nhng vi cng ln hn nhiu. Mng vi sinh vt

s dng v xc vi sinh vt cht theo nc tri khi b c tch khi nc

thi b lng t 2. m bo qu trnh oxy ho sinh ha din ra n

nh, oxy c cp cho b lc bng cc bin php thng gi t nhin hoc

thng gi nhn to. Vt liu lc ca b lc sinh hc c th l nha Plastic,

x vng gm, Granit

B lc sinh hc nh git

B c dng hnh vung, hnh ch nht hoc hnh trn trn mt bng,

b lc sinh hc nh git lm vic theo nguyn tc sau :

18


19/77

Nc thi sau b lng t 1 c a v thit b phn phi,

theo chu k ti u nc trn ton b b mt b lc. Nc thi sau khi lc

chy vo h thng thu nc v c dn ra khi b. Oxy cp cho b ch

yu qua h thng l xung quanh thnh b.

Vt liu lc ca b sinh hc nh git thng l cc ht cui,

ng knh trung bnh 20 30 mm. Ti trng nc thi ca b thp (0,5

1,5 m3/m3 vt liu lc /ngym). Chiu cao lp vt liu lc l 1.5 2m.

Hiu qu x l nc thi theo tiu chun BOD t 90%. Dng cho cc trm

x l nc thi c cng sut di 1000 m3/ngym.

B lc sinh hc cao tiB lc sinh hc cao ti c cu to v qun l khc vi b lc sinh hc

nh git, nc thi ti ln mt b nh h thng phn phi phn lc. B c

ti trng 10 20 m3 nc thi/1m2b mt b /ngym. Nu trng hp

BOD ca nc thi qu ln ngi ta tin hnh pha long chng bng nc

thi lm sch. B c thit k cho cc trm x l di 5000

m3

/ngym3.3.2.2. B hiu kh bn hot tnh B Aerotank

L b cha hn hp nc thi v bn hot tnh, kh c cp lin tc

vo b trn u v gi cho bn trng thi l lng trong nc thi v

cp oxy cho vi sinh vt oxy ha cc cht hu c c trong nc thi. Khi

trong b, cc cht l lng ng vai tr l cc ht nhn cho cc vi

khun c tr, sinh sn v pht trin dn ln thnh cc bng cn gi l bnhot tnh. Vi khun v cc vi sinh vt sng dng cht nn (BOD) v cht

dinh dng (N, P) lm thc n chuyn ho chng thnh cc cht tr

khng ha tan v thnh cc t bo mi. S lng bn hot tnh sinh ra

trong thi gian lu li trong b Aerotank ca lng nc thi ban u i

vo trong b khng lm gim nhanh cc cht hu c do phi s dng

li mt phn bn hot tnh lng xung y b lng t 2, bng cch

tun hon bn v b Aerotank m bo nng vi sinh vt trong b.

19


20/77

Phn bn hot tnh d c a v b nn bn hoc cc cng trnh x l

bn cn khc x l. B Aerotank hot ng phi c h thng cung cp

kh y v lin tc.

3.3.2.3. Qu trnh x l sinh hc k kh - B UASB

3.3.2.3.1. Qu trnh x l sinh hc k kh

Qu trnh phn hy k kh l qu trnh phn hy sinh hc cc cht

hu c c trong nc thi trong iu kin khng c oxy to ra sn phm

cui cng l kh CH4 v CO2 (trng hp nc thi khng cha NO3- v

SO42-). C ch ca qu trnh ny n nay vn cha c bit n mt cch

y v chnh xc nhng cch chung, qu trnh phn hy c th cchia ra cc giai on nh sau:

Hnh 2: S chuyn ha vt cht trong iu kin k kh

3 giai on u, COD ca dung dch hu nh khng thay i, n

ch gim trong giai on methane ha. Sinh khi mi c to thnh lin

tc trong tt c cc giai on.

20

VT CHT HU C

PROTEINS HYDROCARBON LIPIDS

ACID AMIN / NG

ACID BO

ACETATE / H2

CH4

/ CO2

Thy phn

Acid ha

Acetic ha

Methane ha

Vi khun lipolytic, proteolytic vcellulytic

Vi khun ln men

Vi khun to kh H2

Vi khun methaneha

GIAI ON VT CHTLOI VI KHUN


21/77

Trong mt h thng vn hnh tt, cc giai on ny din ra ng thi

v khng c s tch ly qu mc cc sn phm trung gian. Nu c mt s

thay i bt ng no xy ra, cc giai on c th mt cn bng. Pha

methane ha rt nhy cm vi s thay i ca pH hay nng acid bo

cao. Do , khi vn hnh h thng, cn ch phng nga nhng thay i

bt ng, c pH ln s qu ti.

Cc yu t nh hng n qu trnh phn hy k kh

duy tr s n nh ca qu trnh x l k kh, phi duy tr c

trng thi cn bng ng ca qu trnh theo 4 pha nu trn. Mun vy

trong b x l phi m bo cc yu t sau:

Nhit : khong 30350C. Nhit ti u cho qu trnh

ny l 350C.pH:pH ti u cho qu trnh dao ng trong phm vi rt hp,

t 6.5 n 7.5. S sai lch khi khong ny u khng tt cho pha methane

ha.

Cht dinh dng: Cn cht dinh dng theo t l

COD:N:P = (4001000):7:1 vi sinh vt pht trin tt, nu thiu th b

sung thm. Trong nc thi sinh hot thng c cha cc cht dinh dng

ny nn khi kt hp x l nc thi sn xut v nc thi sinh hot th

khng cn b sung thm cc nguyn t dinh dng.

kim: kim ti u cn duy tr trong b l 15003000

mg CaCO3/l to kh nng m tt cho dung dch, ngn cn s gim pH

di mc trung tnh.

Mui (Na+, K+, Ca2+): Pha methane ha v acid ha lipid

u b c ch khi mn vt qu 0,2 M NaCl. S thy phn protein trong

c cng b c ch mc 20 g/l NaCl.

Lipid: y l cc hp cht rt kh b phn hy bi vi sinh

vt. N to mng trn VSV lm gim s hp th cc cht vo bn trong.

21


22/77

Ngoi ra cn ko bn ni ln b mt, gim hiu qu ca qu trnh chuyn

i methane.

Kim loi nng: Mt s kim loi nng (Cu, Ni, Zn) rt

c, c bit l khi chng tn ti dng ha tan. Trong h thng x l k

kh, kim loi nng thng c loi b nh kt ta cng vi carbonate v

sulfide. Ngoi ra cn m bo khng cha cc ha cht c, khng c hm

lng qu mc cc hp cht hu c khc.

B UASB

Nc thi c a trc tip vo di y b v c phn phi

ng u , sau chy ngc ln xuyn qua lp bn sinh hc ht nh(bng bn) v cc cht bn hu c c tiu th .

Cc bt kh mtan v cacbonic ni ln trn c thu bng cc chp

kh dn ra khi b.

Nc thi tip theo s din ra s phn tch 2 pha lng v rn. Pha

lng c dn ra khi b, cn pha rn th hon lu li lp bng bn.

S to thnh v duy tr cc ht bn l v cng quan trng khi vnhnh b UASB.

3.3.2.4. B sinh hc theo m SBR (Sequence Batch Reactor)

H thng x l sinh hc tng m bao gm a nc thi vo b phn

ng v to cc iu kin cn thit nh mi trng thiu kh (khng c oxy,

ch c NO3-), k kh (khng c oxy), hiu kh (c oxi, NO3- ) cho vi

sinh tng sinh khi, hp th v tiu ha cc cht thi hu c trong ncthi.

Cht thi hu c (C,N,P) t dng ha tan s chuyn ha vo sinh

khi vi sinh v khi lp sinh khi vi sinh ny lng kt xung s cn li nc

trong tch cht nhim, chu k x l trn li tip tc cho mt m nc

thi mi.

22


23/77

PHN 4: LA CHN CC

PHNG N X L

x l nc thi ca nh my ch bin thy hi sn nhm a ra cc

phng n x l.

4.1. Phng n 1.

23

Nc thi

My p bn

Song chnrc

B lng ct

B iu ha

B lng ng kthp ng t sinh

hc

B Aerotank

B lng 2

B kh trng

B phn hybn hiu kh

Ngun tip nhn

em san lp mt ng

em chn lp

ng dn nc

ng dn bn

ng dn nc tun hon

ng thi kh

B cha bn

My thikh

Thi b, lmphn bn

My thi kh

ng dn bn tunhon

Sn phi ct

Hnh 4.1: S cng ngh phng n 1


24/77

Thuyt minh quy trnh cng ngh

Nc thi qua song chn rc c tch b mt phn rc c kch

thc ln, rc t y c thu em lm thc n cho gia sc, chn lp.

Nc thi chy qua b lng ct lng bt ct ht ct c kch thc ln.

Nc thi c ly qua mng thu v bm ln b iu ha, c gn h thng

thi kh n nh lu lng v nng . Lng ct lng b lng ct

c a qua sn phi ct lm kh ct s dng cho mc ch xy dng

hay san lp ng.

Trc khi n cng trnh x l chnh (b Aeroten), nc c a n

b lng ng kt hp ng t sinh hc tin hnh lm thong s b gipvic gim mt phn cc hp cht hu c v lng cc thnh phn l lng.

Nc thi c thnh phn hu c gim ng k c a n b lng II

lng bn (vi sinh vt). Bn lng b lng II c tun hon li b aeroten

v b ng t sinh hc. Nc sau lng II tha iu kin thi ra ngun tip

nhn. Bn c n nh ti b sinh hc hiu kh, y, mt phn nc

c tch khi bn v c dn tr li b iu ha. Trc khi em bn i b, bn c gim m ng k ti my p bn .

u im

- Chim din tch xy dng nh hn bi s lng cng trnh t (gim

bt 1 cng trnh x l sinh hc chnh l b k kh, thm vo x l s b

ti b lng I trc Aeroten).

- t nhy cm vi cc hp cht gy c ch.- Chi ph nng lng cao hn.

Nhc im

- Xy dng v qun l phc tp.

- i hi ngi qun l c chuyn mn cao.

- Chi ph vn hnh cao v cn nhiu my thi kh nn tn nhiu nng

lng.- Kh nit cha trit . D b tt nghn b lc sinh hc.

24


25/77

4.2. Phng n 2

25

Nc thi

Sn phi bn

B lc sinhhc cao ti

ng dn bn

ng dn kh

Song chn rc

B lng ct

B iu ha

B lng 1

B UASB

B lng 2

B kh trng

B nn bn

Ngun tip nhn

Ra ct, em san lp mt ng

em chn lp

ng dn nc

ng dn nc tun hon

B cha bn

My thikh

Sn phi ct

Thi b hoclm phn bn

ng dn bn tun hon

Hnh 4.2: S cng ngh phng n 2


26/77


Nc thi qua song chn rc c tch b mt phn rc c kch

thc ln, rc t y c thu em chn lp, thi b. Nc thi chy qua

b lng ct. Nc thi c ly qua mng thu v bm ln b iu ha, c

gn h thng thi kh n nh lu lng v nng . Sau , nc thi

c bm n b lng 1, c s dng l b lng ng tch mt phn

cht hu c d lng. Bn thu c ti y l dng bn ti, c bm v

b cha bn. Nc c tip tc a qua b UASB, sau cng trnh ny

nc c a qua b lc sinh hc cao ti. Nc thu c cho chy qua b

lng t 2, sau kh trng bng clo trc khi a ra ra ngun tip nhn.Bn d c thu ti b cha bn, em nn bn gim m, ri

a qua sn phi bn tip tc lm gim bt lng nc. Bn sau khi x

l c em chn lp hoc s dng bn cho cy trng. Nc t b nn

bn c tun hon v b iu ha tip tc tham gia qu trnh x l.

u im

- Vn hnh tng i n gin.- Ph hp cho cc loi nc thi c hm lng COD t thp n cao.

- X Nng cn kh t 15%-25%.

Khuyt im

- Khng ph hp vi nc thi c SS cao.

- D b bt kn b lc sinh hc cao ti.

- Phi s dng ni c nhiu t thng l vng nng thn, th trn.- C s dng polymer chm vo tng kh nng tch nc.

- Hot ng ph thuc vo iu kin thi tit v kh hu.

- Cn c lao ng th cng xc bn kh t sn phi bn ln xe ti.

- Thi gian lm kh bn di.

26


27/77

4.3. Phng n 3

27

Nc thi

Phn bn

My thikh

ng dn nc

ng dn bn

ng dn bn tun hon

ng dn nc tun hon

Song chn rc

B lng ct

B iu ha

B lng 1

B UASB

B aerotank

B lng 2

B kh trng

B nn bn

Ngun tip nhn

em san lp mt ngem chn lp

ng dn kh

Sn phi ct

Hinh 4.3: S cng ngh phng n 3

Bm clo

My p bn


28/77


Nc qua song chn rc c a n b UASB tng t nh

phng n 2. Nc sau khi qua cng trnh ny tip tc c x l hiu khti aerotank, ri chy trn qua b lng t 2. Bn thu c t b lng t 2

l bn hot tnh, mt phn c bm tun hon li b aerotank, phn cn

li c bm qua b cha bn tip tc x l. Nc c kh trng bng

Clo, t TCVN 5945- 2005 ct B trc khi thi ra ngun tip nhn.

Bn thi ra b lng 1, b UASB, b lng 2 s c bm qua b

nn bn tch m, gip gim ti lng ng k. Lng bn sau ca qua my p bn c th tch nc ti mc ti a, lng bn sau khi

p c th s dng bn cho cy trng hoc em chn lp. Nc p thu t b

nn bn, my p bn c tun hon li b iu ha tip tc x l.

u im

- Thng c s dng, do n ph hp vi iu kin kh hu cc

nc nhit i.

- Vn hnh tng i n gin.

- Ph hp cho cc loi nc thi c hm lng COD t thp n cao.

- Nhng nm gn y UASB c ng dng rng ri hn cc cng

ngh khc do nguyn l qu trnh c xem l thun tin v n gin nht,

nhng hn ch trong qu trnh vn hnh UASB c th d dng khc phc

bng cc phng php x l s b. Tnh kinh t cng l mt u im caUASB.

- Chi ph u t thp

- Nng cn kh t 20%-30%

- Khng s dng ha cht

28


29/77

Khuyt im

- Rt nhy cm vi cc hp cht gy c ch.- Thi gian vn hnh khi ng di (3 4 thng).

- Trong mt s trng hp cn x l th cp gim s sinh mi.

- Thi gian lm kh bn di.

- Hot ng khng ph thuc vo iu kin mi trng v thi tit.

- Tuy nhin nhng mt hn ch ny d khc phc. X l s b tt s

m bo c mi trng sinh trng thun li cho vi sinh vt k kh. Nu

cy vi khun to acid v vi khun to methane trc (phn tru b ti) vi

nng thch hp v vn hnh vi ch thy lc 1/2 cng sut thit k

th thi gian khi ng c th rt ngn xung t 2-3 tun.

Kt lun

Tm li qua ba phng n x l nc thi ch bin thy hi sn nhm

quyt nh chn phng n 3 tin hnh tnh ton v thit k h thng xl.

L do m nhm chn phng n 3.

- Ph hp vi iu kin kh hu Vit Nam.

- Vn hnh tng i n gin.

- Khng x dng nhiu ha cht trong qu trnh vn hnh.

- Chi ph vn hnh thp.

- Khng phi b tt nghn h thng x l nh 2 phng n, v

phng n 1. Bn cnh khng phi tn chi ph cho vic mua cc

loi vt liu lc.

29


30/77

PHN 5: TNH TON- THIT K H THNG

X L NC THI THY HI SN CNGXUT 1000M3/NGYM THEO S

CNG NGH CA PHNG N 3

Mt s thng s u vo

Lu lng trung bnh ngy m

ngaydemmQtb /1000 3=

ngaydemmkQQ tbngayngay /17007.110003

maxmax ===

ngaydemmkQQ tbngayngay /4004.010003

minmin ===

Lu long theo h

hmQtbh /67.4124

1000 3==

hmkQQ tbhh /83.707.124

1000 3maxmax ===

hmkQQ tbhh /67.164.024

1000 3minmin ===

Lu lng theo s

smQtbs /01157.0

360024

1000 3=

=

smkQQ tbss /0197.07.1360024

1000 3maxmax =

==

smkQQtbss

/0046.04.0360024

1000 3minmin

=

==

maxk , mink : H s khng iu ha gi ln nht, nh nht

30


31/77

5.1. Song chn rc

Nhim v ca song chn rc

Song chn rc gi li cc tp cht c kch thc ln nh: xng c,

cc loi v ngu, tm, cua... Lng rc thi c tch ra song chn rc s

c a i lm thc n cho gia sc hoc c th em i chn lp. y l

cng trnh u tin trong thnh phn ca trm x l nc thi.

Ni dung tnh ton SCR

Kch thc mng t song chn

Tnh ton SCRChn vn tc qua song chn rc l smv /5.0=

Khong cch gia hai thanh chn l b = 0.02m

dy lp nc trong mng l mh 14.01 =

dy ca mi thanh chn: d = 0.005m

Tnh ton s khe ca song chn rc:

147.1414.002.05.0

05.10197.0

1

max =

=

= khbv

Qn s khe

Vi k = 1.05 l h s tnh hin tng thu hp dng chy

Chn s khe song chn rc l 14 khe, s thanh chn rc l 15 thanh.

B rng tng cng ca song chn rc

( ) ( ) mnbndBs 35.01402.0114005.01 =++=++=

Kim tra vn tc dng chy trc song chn rc khc phc kh nngng cn.

smsmhB

Qv

s

skt /4.0/41.014.035.0

0197.0

1

max >=

=

=

Tn tht p lc qua song chn rc:

mmmmm

g

vVh

s1506006.0

81.92

41.05.0

7.0

1

27.0

1 2222


32/77

Chiu cao tng cng ca song chn rc

mhhhH bvs 446.03.0006.014.01 =++=++=

5.2. B lng ct

Nhim v ca b lng ct

B lng ct c ch nhim v lng ct, khng lng cc tp cht hu c.

Ct ly ra em i ra, qua sn phi ct ri em b, hoc s dng san lp

mt ng.

Ni dung tnh ton gm

Th tch ca b lng ct

Lng ct lng trong mt ngy m

Chn thi gian lu ca b lng ct ngang: t = 30s

Chn vn tc nc trong b lng ngang: nv = 0.2 (m/s)

Th tch tng cng ca b lng ct ngang3

max 0.0197 30 0.591sW Q t m= = =

Din tch mt ct ngang ca b lng ct

2max 0985.02.0

0197.0m

v

QF

n

sn ===

Chiu rng ca b lng ct ngang

0.09850.4

0.25nF m

H= = =B

Vi H = 0.25 m l chiu cao cng tc ca b lng ct ngang.Chia b lng ct thnh 2 n nguyn n = 2

350 mm

32


33/77

Chiu di ca b lng ngang

0.5913

2 0.4 0.25

WL m

n B H= = =

Chn chiu cao bo v ca b lng ct: 0.25 mVy kch thc ca b lng ct: L x B x H = 3 x 0.4 x 0.5 m.

Lng ct trung bnh sau mi ngy m

ngaydemmqQ

W tbngayc /15.01000

15.01000

100030 =

=

=

Vi q o : lng ct trong 1000m 3 nc thi, q 0 =0.15m 3 ct/ngaydem

Chiu cao lp ct trong b lng ct ngang trong ngy m0.15 2

0.1253 0.4 2

c xc

W th m

L B n

= = =

Vi t x l chu k x ct, t x =2 ngy m.

Tnh din tch sn phi ct

Nhim v ca sn phi ct

Ra cn bm trong qu trnh lng ct, gy mi trong ct. ng thi lm

kh ct em tn dng tri mt ng.

Chiu di ca sn phi ct: L = 3 m

Chn thi gian phi ct = chu k x ct, t = 2 ngy m

Th tch ct trn sn: W = 0.3 m3

Tnh chiu rng sn phi ct:

w 0.3

0.42 0.125 3B mt h L= = =

Din tch sn phi ct: B x L = 0.4m x 3m

5.3. B iu ha.

Nhim v ca b iu ha

Gim bt s dao ng ca hm lng cc cht bn trong nc do qu trnh

sn xut thi ra khng u.

Tit kim ha cht trung ha nc thi.

33


34/77

Gi n nh lu lng nc i vo cc cng trnh x l tip theo.

Hm lng BOD, COD, SS sau b iu ha t

BOD = 95% x 1050 = 998 mg/l

COD = 95% x 1500 = 1425 mg/l

SS = 85% x 270 = 230 mg/l

Xc nh th tch b iu ha

Th tch tch ly

Th tch tch ly dng vo ca gi th i c xc nh:

( ) ( 1)v i v i iV V Q

= +

Trong

Vv(I-1): th tch tch ly dng vo ca gi trc (m3)

Qv(i): lu lng nc thi ca gi ang xt (m3/h)

Th tch tch ly bm i ca gi th i

( ) ( 1) ( )b i b i b iV V Q

= +

Trong :

Vb(I-1): th tch tch ly bm ca gi trc (m3)

Qb(i): lu lng bm ca gi ang xt (m3/h)

Th tch b iu ha

Da vo cc cng thc tnh nh trn ta c th lp bng th tch tch

ly cho mi gi trong ngy nh bng sau.

Gi Q(m3/h)

Th tch tch

ly vo b

(m 3)

Th tch tch

ly bm i

(m3)

Hiu s th

tch

)( 3mVV itli

bd

1 22 22 41.6 19.6

2 20 42 83.4 41.43 15 57 124.8 67.8

i

bdVi

tlV

34


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Gi Q(m3/h)

Th tch tch

ly vo b

(m 3)

Th tch tch

ly bm i

(m3)

Hiu s th

tch

)( 3mVV itlibd

4 15 72 166.5 94.55 15 87 208 1216 17 104 249.7 145.77 35 139 291.2 152.2 (max)8 70.8 209.8 332.9 123.19 70 279.8 374.4 94.6

10 69.2 349 416.1 67.111 65 414 457.6 43.612 38 452 499.3 47.313 35 487 540.8 53.814 35 522 582.5 60.515 39 562 624 6216 79 641 665.6 24.617 54 695 702.3 7.318 54 742 748.8 6.8

19 45 787 790.6 3.620 44 831 832 121 49 880 873.8 -6.222 48 928 956.8 28.823 42 970 956.7 -13.3 (min)24 30 1000 1000 0

Bng 5.1: Th tch tch ly theo gi

Th tch l thuyt b iu ha bng hiu i s gi tr dng ln nht v

gi tr m nh nht ca ct hiu s th tch tch ly

( ) == minmax VVV LTdh 152.2 (- 13.3) = 165.5 (m3)

Th tch thc t ca b iu ha

( ) ( ) ( )LTdhTTdh VV 2.11.1 =

( ) )(6.1985.1652.13mV TTdh ==

Vy th tch thc ca b iu ha l: 198.6 m3

i

bdV

i

tlV

35


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Da vo s liu bng th tch tch ly theo gi, ta v c biu tch ly

theo gi

0

200

400

600

800

1000

1200

0 5 10 15 20 25 30

Th tch tch ly vo b Th tch tch ly bm i

Biu 5.1: Biu tch ly

Chn b c hnh dng trn: Chiu cao lp nc ln nht hmax = 4m

Chiu cao bo v hbv = 0.5m

Vy chiu cao tng cng:

H = hmax + hbv = 4 + 0.5 = 4.5(m)

ng knh b: )(95.74

6.19844m

H

VD ===

Vy kch thc b iu ha: D x H = 7.95m x 4.5m

Tnh ton bm dng trong b iu ha

Ti b iu ha c t bm nhng chm bm nc thi qua b lng 1, do

ta phi tnh cng sut ca bm t ti y.

Ct p ton phn ca bm: H = 4.5m + 0.3m = 4.8m

Lu lng bm: Q = 1000 m3/ngy.m

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Cng sut ca my bm:

( )kWgHQ

N 68.0864008.01000

10008.481.91000

1000=

==

Cng sut thc t ca my bm: ( ) )(37.102.168.05.15.1 HPkWNNTT ====

Xc nh hiu qu kh BOD5 ca b iu ha

Da vo kt qu phn tch biu hoc bng, ta xc nh c thi

im b cn nht l lc 7 gi.

- Thi im tnh ton bt u t lc 8 gi.

Th tch nc trong b iu ha gi ang xt th I c xc nhtheo cng thc sau:

Trong :

V(i): th tch nc trong b iu ha gi ang xt (m3)

V(I-1): th tch nc trong b iu ha gi trc (m3

) Vin(i): th tch nc i vo b iu ha gi ang xt (m3)

Vout(i): th tch nc bm ra khi b iu ha gi ang xt (m3)

Ta tnh c th tch nc trong b iu ha vo lc 8 gi:

( ) ( ) ( ) ( ) ( )3

8878 2.296.418.700 mVVVV outin =+=+=

Th tch nc trong b iu ha vo lc 9 gi:

( ) ( ) ( ) ( ) ( )3

9989 6.576.41702.29 mVVVV outin =+=+=Gi s khi nc trong b iu ha c xo trn hon ton. Vy hm lng

BOD5 trung bnh bm ra khi b c th tnh theo biu thc sau:

( ) ( ) ( 1) ( 1)

( )

( ) ( 1)

. .in i in i i iout i

in i i

V S V S S

V V

+

=

+

Trong : Sout(i): hm lng BOD5 trung bnh ca dng ra gi ang

xt (mg/l)

( ) ( 1) ( ) ( )i i in i out iV V V V

= +

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Sin(i): hm lng BOD5 trung bnh ca dng vo gi

ang xt (mg/l)

V(i-1): th tch nc trong b iu ha gi trc (m3)

Vin(i): th tch nc i vo b iu ha gi ang xt (m3)

Vy ta tnh c hm lng BOD5 trung bnh ca dng ra vo lc 8

gi:

( )

( ) ( )

( )

)/(150008.70

1330015008.70.. 3

78

7788

8 mmgVV

SVSVS

in

inin

out =++

=++

=

Hm lng BOD5 trung bnh ca dng ra vo lc 9 gi:

( )

( ) ( ) ( ) ( )

( ) ( )

)/(13662.2970

15002.29131070.. 3

89

8899

9 mmgVVSVSVS

in

inin

out =++=

++=

Gi

trong

ngy

Q(m3/h)

Th tch

nc

trong b

(m3)

BOD

vo

(mg/l)

BOD

trung bnh

ra khi b

(mg/l)

Ti lng

BOD trc

iu

ha(kgBOD5)

Ti lng BOD

sau iu

ha(kgBOD5/h)

8 70.8 29.2 1500 1500 106.2 (max) 62.4 (max)9 70 57.6 1310 1366 91.7 56.810 69.2 85.2 1250 1277 86.5 53.111 65 108.6 1220 1237 79.3 51.412 38 103 1030 1170 39.1 48.613 35 96.4 790 969 27.6 40.314 35 89.8 770 785 26.9 32.615 39 87.2 855 795 33.3 33.1

16 79 124.6 1350 1090 86.1 45.317 54 137 1310 1338 70.7 55.618 54 149.4 1230 1287 66.4 55.519 45 152.8 790 1128 35.5 46.920 44 155.2 870 807 38.3 33.521 49 162.6 1150 937 56.3 38.922 48 169 1250 1172 60 48.723 42 169.4 990 1198 41.6 49.824 30 157.8 695 945 20.8 39.3

1 22 138.2 695 695 15.3 28.9 (min)2 20 116.6 792 707 15.8 29.4

38


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Gi

trong

ngy

Q(m3/h)

Th tch

nc

trong b

(m3)

BOD

vo

(mg/l)

BOD

trung bnh

ra khi b

(mg/l)

Ti lng

BOD trc

iu

ha(kgBOD5)

Ti lng BOD

sau iu

ha(kgBOD5/h)

3 15 90 890 803 13.5 (min) 33.44 15 63.4 910 892 13.6 37.15 15 36.8 1060 938 15.9 39.16 17 12.2 1220 1110 20.7 46.27 35 0 1330 1301 46.5 54.1Trung

bnh 41.6 1050 1060 46.1 44.2

Bng 5.2: Hm lng BOD5 trung bnh v ti lng BOD5 trc v sau

b iu ha

T s Trc iu ha Sau iu haLmax : Ltb 106.2 : 46.1 = 2.3 62.4 : 44.2 = 1.4

Lmin : Ltb 13.5 : 46.1 = 0.3 28.9 : 44.2 = 0.65Lmax : Lmin 106.2 : 13.5 = 7.8 62.4 : 28.9 = 2.2

Bng 5.3: H s khng iu ha v ti trng BOD5

Cc dng xo trn trong b iu ha

Dng khuy trn Gi tr n vKhuy trn c kh 4-8 W/m3th tch bTc kh nn 10-15 Lit/m3th tch b.pht

Bng 5.4: Cc dng xo trn trong b iu ha

Chn khuy trn b iu ha bng h thng thi kh.

Chn: tc kh nn R=13lit/m3pht=0.013m3/m3pht

Lu lng kh nn cn cho khuy trn

smhm

phtmRVq LTdhk

/036.0/129

/1515.2013.05.16533

3

)(

==

===

39


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Tnh ton my nn kh cho b iu ha

p lc cn thit cho h thng ng kh nn

Hd = hd + hc + hf+ H

Trong :

o hd, hc: tn tht p lc do ma st dc theo chiu di trn ng

ng dn v tn tht cc b ti cc im un, khc quanh.

hd + hc 0.4m

o hf: tn tht qua h thng phn phi kh

hf 0.5m

o H: ngp su ca ng phn phi kh, ly bng chiu cao hu

ch ca b iu ha

H = 4m

Vy p lc cn thit

Hd = 0.4m + 0.5m + 4m = 4.9m

p lc ca my nn kh

( ) ( ) ( )atmHP dm 47.133.109.433.10

33.1033.10 =+=+=

Theo cng thc 152 gio trnh X l nc thi ca Hong Hu ta

c cng sut ca my nn kh:

( )[ ] ( )[ ] KWqPN kmLT 435.1036.0147.110234400

1102

34400 29.029.0 ===

Cng sut tnh ton ca my nn kh

KWN

N LTtt

05.27.0

435.1===

Tnh ton ng knh ng dn

Chn loi khuch tn kh l ng mng khoan l dng li c lu

lng kh q n = 92 l/m3phut.

S ng khuych tn kh

40


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)(2492

1.22151ci

q

qn

n

k ===

Chn tc dng kh trong ng dn chnh l 8m/s. Vy ta c

ng chnh c ng knh trong

mmmv

q

d

k

7.750757.08

036.044

==

=

=

Chn loi ng nha HDPE ca nha Bnh Minh dngoi = 80mm, b

dy 2.3 mm

Chn tc dng kh cc ng dn nhnh l 8m/s. Vy ta c

ng nhnh c ng knh trong

mmmv

q

d

n

6.150156.060

1

8

092.044

==

=

=

Chn loi ng nha HDPE ca nha Bnh Minh dngoi = 20mm, b

dy 2.3 mm

Trn cc ng nhnh c c l ng knh dl = 5mm.Chn vn tc thot ra mi l l 10m/s. Lu lng kh thot ra

khi 1 l

( )

phtmsm

dvSvq l

l

l

kh

/1078.11/10963.14

10510

43334

232

==

=

=

==

S l trn mi ng nhnh l:

8.7/1078.11

/10.9233

33

=

==

phtm

phtm

q

qn

l

kh

n

S l trn mi nhnh l 8 (l)

5.4. B lng 1

Nhim v b lng 1

41


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Loi b cc tp cht l lng cn li trong nc thi qua b iu ha. y

cc cht l lng c t trng ln hn t trn ca nc s lng xung y.

Hm lng cht l lng sau khi qua b lng t 1 cn t 150 mg/l.

Hm lng sau khi ra khi b lng 1 phi t:

BOD = 80% x 998 = 789.4 mg/l

COD = 80% x 1425 = 1140 mg/l

SS = 60% x 230 = 138 mg/l 150 mg/l

Chn b lng t 1 dng trn, nc thi i vo t ng trung tm, thu nc

theo chu vi b.

Thng s Gi trDy c trng

Thi gian lu nc (gi) 1.5-2.5 2Ti trng b mt (m3/m2ngay) 32-48Lu lng trung bnh 32-48

Lu lng cao im 80-120Ti trng mng trn

(m3/m.ngay)

125-500

ng trung tm

ng knh

Chiu cao

15 20%d D=

55 65%h H=

Chiu su b lng (m) H=3-4.8 4ng knh b lng (m) D=3-6 5.64 dc y (mm/m) 62-167 83Tc thanh gt bn

(vng/pht)

0.02-0.05 0.03

Bng 5.5: Cc thng s thit k c trng cho b lng ly tm

Gi s ti trng b mt thch hp cho loi cn ti ny l

=AL 40 m3/m2.ngy

Din tch b mt b lng l

42


43/77

2

23

23

25/40

/1000m

ngaymm

ngaymm

L

QA

A

tbngay ===

ng knh b lng

mAD 64.52544 ===

ng knh ng trung tm

mDd 13.164.5%20%20 ===

Chn chiu su hu ch ca b lng H=4m

Chiu cao lp bn lng hb = 0.7m

Chiu cao an ton h=0.5mVy chiu cao tng cng ca b lng t 1

Htc= H+h+ hb = 4m+ 0.5m+0.7m = 5.2m

Chiu cao ng trung tm

mHh 4.24%60%60 ===

Vy kch thc b lng 1: D x H=5.64m x 5.2m

Kim tra li thi gian lu nc ca b lngTh tch phn lng

( ) ( ) 32222 96413.164.544

mHdDW ===

Thi gian lu nc

hhQ

Wt

tbh

5.13.267.41

96>===

Ti trng mng trn

mngaymD

QL tbnays /44.5664.5

1000 3=

=

=


44/77

ngyKgSSKg

gngymmgSSM

tuoi/92

1000

14.0/1000/230 33 ==

Gi s bn ti ca nc thi thy sn c hm lng cn 5% (tc l

c m 95%).T s VSS:TSS=0.75 v khi lng ring bn ti l 1.053kg/lt.

Vy lu lng bn ti cn phi x l l

ngaymngyllKg

ngayKgQtuoi /747.1/4.1747/053.105.0

/92 3==

=

Lng bn ti c kh nng phn hy sinh hc

ngayKgVSSM VSStuoi /699275.0)( == Tnh ton mng trn.

Chiu di mng trn

L=0.85 x D=0.85 x 5.64 = 4.8 m

Ti trng trn mt mp di mng trn

sml

m

mlsmq /1.4

8.4

/1000/0197.0 33=

=

Chn tm x khe hnh ch V, gc y 90o iu chnh cao mp

mng. Chiu cao hnh ch V l 5 cm, y ch V l 10 cm, mi m di c 5

khe ch V, khong cch gia cc nh l 20 cm.

Chiu cao mc nc h trong khe ch V

qo=5

q= 1,4 h5/2

mmmh 50050.0)4.15

0041.0( 5/2 ==

=

Ph hp tiu chun cho php 50 mm

5.5. B UASB

Nhim v ca b UASB

44


45/77

Lm gim ng k hm lng COD, BOD trong nc thi bng

cch s dng lp cn l lng (c cha rt nhiu vi sinh vt ym kh) trong

dch ln men nh h thng nc thi chy t pha di ln. ng thi lm

tin cho qu trnh x l hiu kh trong b aerotank tip theo.

Hm lng cc cht sau khi qua khi b UASB t:

BOD = 25% x 789.4 = 197 mg/l

COD = 35% x 1140 = 399 mg/l

SS = 138 mg/l

Nng nc

thi,

mgCOD/l

T l COD

khng tan, %

Ti trng th tch 30oC, kg COD/m3.ngy

Bn bng

Bn ht

(khng kh

SS)

Bn ht kh

SS

200010 30

30 60

2 4

2 4

8 12

8 14

2 4

2 4

2000 6000

10 30

30 60

60 100

3 5

4 8

4 8

12 18

12 24

3 5

2 6

2 6

6000 9000

10 30

30 60

60 100

4 6

5 7

6 8

15 20

15 24

4 6

3 7

3 8

9000 18000 10 30 5 8 15 24 4 6

45


46/77

Bng 5.6: Cc thng s thit k cho b UASB

(Ti trng th tch hu c ca b UASB bn ht v bn bng cchm

lng COD vo v t l cht khng tan khc nhau)

Bng 5.7: Ti trng th tch hu c ca b UASB bn ht c hm

lng bn trung bnh 25kgVSS/m3 (ph thuc vo nhit vn hnh,

nc thi c VFA ha tan, nc thi khng c VFA v nc thi c

cn l lng chim 30% tng COD

Thc nghim trn m hnh Pilot rt ra c kt qu sau

Bn nui cy ban u ly t bn ca b phn hy k kh t qu

trnh x l nc thi sinh hot b vi hm lng 30KgSS/m3.

T l MLVS/MLSS ca bn trong b UASB=0.75

Ti trng b mt phn lng L =A 12 ngaymm23 /

ti trng th tch L 0 =3KgCOD/m 3 .ngy, hiu qu kh COD t

65% v BOD 5 t 75%

Nhit , oC

Ti trng th tch hu c (kg COD/m3.ngy)

Nc thi VFA Nc thi khng

VFAC 30% COD-SS

1520

25

30

35

40

2 44 6

6 12

10 18

15 24

20 32

1.5 3.02 4

4 8

8 12

12 18

15 24

1.5 22 3

3 6

6 9

9 14

14 18

46


47/77

Lng bn phn hy k kh cho vo ban u c TS=5%

Y=0.04gVSS/gCOD, kd =0.025ngay 1 ,=60 ngy

Hm lng COD vo b UASB

C 0 = 80% C bandau =80% x 1140 =912mg/l

Hm lng COD vo b UASB

BOD vo = 80%BOD bandau =80% x 789.4 = 789.4mg/l

Din tch b mt phn lng

233.8312

1000m

L

QA

A

tbngay ===

Th tch ngn phn ng b UASB

COD

tbngay

r L

CQV 0

= = 33

33

3041000/3

/912/1000m

ngaymKgCOD

mgngaym=

Chn 5 n nguyn hnh vung, vy cnh mi n nguyn c chiu di l

mn

AW 1.4

5

33.83===

Chiu cao phn phn ng

H= mA

Vr 65.333.83

304==

Chn chiu cao phu thu kh l h =p 1.5m

Chiu cao bo v bvh =0.5m

Chiu cao tng cng b UASB lH tc =h b +h bv +H=4.8+0.5+1.5=6.8m

Chn ti mi b gm 2 phu thu kh.

Mi phu c chiu cao 1.5 m.

y phu thu kh c chiu di bng cnh n nguyn: l = W = 4.1

m v chiu rng w = 1.7m

Vy phn din tch b mt khe h gia cc phu thu kh l

47


48/77

%171001.41.4

7.11.421.41.4100 =

=

=A

AA

A

A pkh

Trong

A: Din tch b mt bA kh : Din tch khe h gia cc phu thu kh

A p : Din tch y phu thu kh

Gi tr ny nm trong khong:A

Akh = 15%20%

Gi s mi n nguyn c 8 ng phn phi kh vo, din tch trung bnh

cho mt u phn phi:

a n = =

au

mm

8

1.41.42.1m 2 /u. [ ]aum /52 2

Lng bn nui cy ban u cho vo b (TS = 5%)

tan4.1821000

tan1

05.0

304/30 33=

=

=

kg

mmkgSS

TS

VCM rss

b

Trong

C SS: Hm lng bn trong b, Kg/m 3

V r : Th tch ngn phn ng m3

TS: Hm lng cht rn cho bn nui cy ban u.

Hm lng COD ca nc thi sau khi x l k kh

COD lmgCODCODE vaoCODra /3991140)65.01()1( ===

Hm lng BOD 5 ca nc thi sau khi x l k kh:

BOD lmgBODBODE vaoBODra /1974.789)65.01()1( ===

Lng sinh khi hnh thnh mi ngy

( )[ ]

cd

x k

QSSYP

+

=1

0

( )[ ]

( )[ ]kg

kggngay

ngaymmgCODkgCODkgVSPx 6.12

/100090015.01

/1000/3991140/04.0

1

33

=+

=

48


49/77

ngaykgVSPx /6.12=

c : Thi gian lu bn, chn c = 10 ngy

Q : Lu lng trung bnh ngy, Q = 1000 m3/ngym

Y : H s sn lng bn, chn Y = 0.5mgVSS/mgBOD5

La : BOD5 ca nc thi dn vo aeroten, La = 197 mg/L

Lt : BOD5 ha tan ca nc thi ra khi aeroten, Lt = 12.62mg/L

X : Hm lng bn hot tnh trong b aeroten, MLVSS = 3000mg/L

Kd : H s phn hy ni bo, Kd = 0.05 ngy-1

Th tch kh mtan sinh ra mi ngy

( )[ ]xbCH PQSSV 42.1159 04 =

( ) 6.1242.110001/1000/399114084.350 33

4= ngaymmgCODVCH

ngaymngay /260/259955 3==Trong

4CHV : Th tch kh metan sinh ra ktc (t = 0 0 C, p = 1 atm)

Q: Lu lng bn vo b k kh, m3/ngy

P x : Sinh khi t bo sinh ra mi ngy, kgVS/ngy

350.84: H s chuyn i l thuyt lng kh metan sn sinh t 1

kg BOD L chuyn hon ton thnh kh metan v CO 2 , lCH 4 /kgBOD L

Lng bn bm ra mi ngy

ngaymmKgSSkgSSkgVS

ngaykgVS

C

PQ

ss

w

w

/56.0/30/75.0

/6.12

75.0

3

3

=

=

=

Lng cht rn t bn d

ngaykgSSmkgSSngaymCQM SSwss /8.16/30/56.033 ===

5.6. B Aerotank.

Nhim v ca b aerotank

49


50/77

B aerotank s dng h thng sc kh xo trn hon ton c nhim v ha

tan oxi kt hp vi bn hot tnh gip kh hon ton hm lng BOD,

COD trong nc thi c a t b UASB qua.

Xo trn v khuch tn oxi bng phng php sc kh

Chiu cao lp nc trong b 4.57 7.62m vic khuch tn kh t

hiu qu cao

Chiu cao bo v (t mt nc n nh b) t 0.3 0.6m

Dng chy nt xo trn nh dng chy xon th chiu rng b phi

ph thuc vo chiu cao

H : B = (1.1 2,2):1 (thng chn 1,5 1)

Tm tt cc s liu tnh ton

Hm lng BOD5 trong nc thi cn t sau x l

Lt = 15% x 197 = 29.6 mg/L 30mg/l

Hm lng COD trong nc thi cn t sau x l: 15% x 399 = 59.85

mg/l

Hm lng cht l lng cn t sau x l

Cs = 22% x 138 = 30mg/l < 100mg/

Xc nh t s tun hon

Qra,X

ra

Qb,X

th

Q,X0

Q+Qth,X

Qth,X

th

LngII

Aeroten

50


51/77

Phng trnh cn bng vt cht i vi b aeroten

( )XQQXQQX ththth +=+0

Vi

Q : Lu lng nc thi

Qth : Lu lng bn hot tnh tun hon

X0 : Nng VSS trong nc thi dn vo Aeroten, mg/L

X : Nng VSS b Aeroten, X = 3000mg/L

Xth : Nng VSS trong bn tun hon, X = 8000mg/L

Do X0 thng rt nh so vi X v X th, do trong phng trnh cn bng

vt cht trn c th b qua i lng QX0 . Khi phng trnh cn bng

vt cht s c dng :

( )XQQXQ ththth +=

Chia hai v ca phng trnh ny cho Q v t t s =Q

Qth ( : c gi

l t s tun hon), ta c :

XXXth +=

Hay 6,0300080003000

=

=

=XX

X

th

vQ

Qth=

Thng s tham kho

Cc thng s tnh ton c bn cho aeroten kiu xo trn hon ton c th

tham kho theo trang 144 sch X l nc thi th v cng nghip

tnh ton thit k cng trnh Lm Minh Trit , Nguyn Phc Dn,

Nguyn Thanh Hng)

Thi gian lu bn c = 5 15 ngy

T s F/M 0.2 0.6 kg/ kg.ngy

Ti trng th tch 0.8 1.92 kgBOD5/m3.ngy

Nng MLSS (Cht rn l lng trong bn lng)

51


52/77

2500 4000 mg/L

T s th tch b/lu lng gi W/Q = 3 5h

T s tun hon bn hot tnh Qth/Q = 0.25 1

iu kin tnh ton qu trnh bn hot tnh xo trn hon ton

MLVSS : MLSS = 0.8

Hm lng bn tun hon Xth = 8000mgVSS/L

Hm lng bn hot tnh trong b aeroten MLVSS = 3000mg/L

Thi gian lu bn trung bnh c = 10ngy

Nc thi ch bin thy sn c cha y lng cht dinh dng

N, P v cc cht vi lng khc

Nc thi sau lng II cha 25mg/L cn sinh hc, trong 65% cn

d phn hy sinh hc

BOD5 : BODL = 0.68

BOD5 : N : P = 100 : 5 : 1

Gi s nguyn t vi lng cng cho sinh trng t bo.

Thng

s

n v Dy gi tr Trung bnh

K gbsCOD/gVSS.ng

y

2 10 5

Ks mg/L BOD

mg/L bsCOD

25 100

10 60

60

40Y mgVSS/mgBOD

mgVSS/mgbsCOD

0,4 0,8

0,3 0,6

0,6

0,4Kd gVSS/gVSS.ngy 0,06 0,15 0,1

(Ngun: Bng 7 9 trang 585 Metcalf & Eddy Wastewater Engineering

Treatment & Reuse McGraw Hill)

Bng 5.8: Thng s ng hc tham kho

52


53/77

Chn

Ks = 50mg/L Y = 0.5mgVSS/mgBOD5Kd = 0.05ngy-1

Kd: H s phn hy ni bo

Y: H s sn lng bn

Cc bctnh ton cho aeroten xo trn hon ton

B1) Xc nh BOD5 ca nc thi u vo v u ra aeroten

Lu lng trung bnh ca nc thi trong mt ngy m

Qtbngay = 1000m3/ngym

Hm lng COD trong nc thi dn vo aerotank: 399 mg/l

Hm lng BOD5 trong nc thi dn vo aeroten La = 197mg/L

Hm lng cht l lng trong nc thi dn vo aeroten

C=138 mg/L

Cho rng cht l lng trong nc thi u ra l cht rn sinh hc (bn hot

tnh), trong c 80% l cht d bay hi v 60% l cht c th phn hy

sinh hc.

B2) Tnh BOD5 ha tan trong nc u raBOD5 (ra) = BOD5 ha tan trong nc u ra + BOD5 ca cht l lng

trong nc u ra.

Tnh BOD5 ca cht l lng trong nc u ra

+ Phn c kh nng phn hy sinh hc ca cht rn sinh hc u ra l

0.6 x 30mg/L = 18mg/L

+ BODL ca cht rn c kh nng phn hy sinh hc u ra l

53


54/77

18mg/L x 1,42 mg O2 tiu th / mg t bo b oxi ha = 25.56mg/L

+ BOD5 ca cht rn l lng u ra = 25.56mg/L x 0.68 = 17.38mg/L

BOD5 ha tan trong nc u ra

BOD5 ht = 30mg/L 17.38mg/L = 12.62mg/L

B3) Xc nh hiu qu x l

Hiu qu x l tnh theo BOD5 ha tan

%96197

/62.12/197=

=

lmglmgEht

Hiu qu x l tnh theo tng cng

%85197 /30/197 == lmglmgEtc

B4) Xc nh th tch cng tc ca b aeroten

( )

( )

( )

( )387.204

1005.013000

62.121975.0100010

1m

KX

LLYQW

cd

tatbngayc =+

=+

=

Vi

c : Thi gian lu bn, chn c = 10 ngy

Q : Lu lng trung bnh ngy, Q = 1000 m3/ngym

Y : H s sn lng bn, chn Y = 0.5mgVSS/mgBOD5

La : BOD5 ca nc thi dn vo aeroten, La = 197 mg/L

Lt : BOD5 ha tan ca nc thi ra khi aeroten, Lt = 12.62mg/L

X : Hm lng bn hot tnh trong b aeroten, MLVSS = 3000mg/L

Kd : H s phn hy ni bo, Kd = 0.05 ngy-1

Gi tr c trng cho kch thc b aerotank xo trn hon ton th

hin trong bng sau

Thng s Gi trChiu cao hu ch (m) 3 - 4.6Chiu cao bo v (m) 0.3 - 0.6Khong cch t y n u khuch tn kh

(m)

0.45 - 0.75

54


55/77

T s rng:su (W:H) 1:1 - 2.2:1

Bng 5.9: Cc kch thc in hnh cho

b aerotank xo trn hon ton

Chn chiu cao hu ch H = 4.3m

Chn chiu cao bo v hbv = 0.5

Vy chiu cao tng cng l:

Htc = 4.3m + 0.5m = 4.8m

Chn t s B:H = 1.5:1, vy chiu rng b l:

B =1.5 x H = 6.45m.

Chiu di b L:

mmm

m

HB

WL 4.7

3.445.6

87.204 3=

=

=

B5) Xc nh lng bn d thi b mi ngy

H s sn lng quan st

333.01005,01

5,0

1=

+

=

+

=

cd

obsK

YY

Lng sinh khi gia tng mi ngy tnh theo MLVSS

( ) ( )ngaykg

kgg

LLQYP tatbngayobsX /4.61

10

62.121971000333.0

/1033

=

=

=

Lng sinh khi tng cng tnh theo MLSS

Lng bn thi b mi ngy

( )

ngaykg

lmgSSngaymngaykgCQPL StbngaySSXbundu

/75.46

10/30/1000/75.76 33

=

==

Vi

( ) ngaykgP

P XSSX /75.768.0

4.61

8.0===

55


56/77

PX(SS) : Lng tng sinh khi tng cng tnh theo MLSS

Qngy,TB x CS : Hm lng cht l lng cn li trong dng ra

B6) Xc nh lu lng bn thi

Gi s bn d c x b mi ngy (dn n b cha bn) t ng ng

dn bn tun hon Qra = Q v hm lng cht rn l lng d bay hi VSS

trong bn u ra chim 80% hm lng cht rn l lng VSS. Khi

lng bn d thi b c tnh ton xut pht t cng thc:

rarab

c XQXQ

XW

+

=

Trong :W: Th tch ca b aerotank, W=204.87 m3

X: Nng VSS trong hn hp bn hot tnh b aerotank,

X=3000mg/l

X ra : Nng VSS trong SS ra khi b lng, X ra =0.8 x 30 =24mg/l

Q b : Lu lng bn thi.

Q = Q tbgay Lu lng nc thi ra khi b lng t 2

T ta tnh c:

ngaydemm

X

XQXWQ

c

raracb

/5.12300010

24100010300087.204 3=

=

=

B7) Xc nh lu lng bn tun hon.

T phng trnh cn bng vt cht trong b aerotank, ta xc nh dc t

s tun hon

6,030008000

3000=

=

=

XX

X

th

vQ

Qth=

Lu lng bn tun hon

ngaymQQth /60010006.03===

Vi

56


57/77

X : Nng VSS b aeroten, X = 3000mg/L

Xth : Nng VSS trong bn tun hon, Xth = 8000mg/L

B8) Xc nh thi gian lu nc ca b aeroten

hhngayngaymm

QW 5917.420487.0

/100087.2043

3

====

B9) Xc nh lng khng kh cp cho Aeroten , s lng thit b

khuch tn kh , ng dn kh

Khi lng BODL cn x l mi ngy

TBngayhoa

raLvaoL QBODBODG ,tan

,, )( =

ngaykgG /14.271100068.062.12

68.0197 =

=

Tnh lng oxi yu cu theo l thuyt

( ) ( ) ngaykgPGM Xoxi /1844.6142.114.27142.1 ===

Cho hiu qu vn chuyn oxi ca thit b thi kh l 8%, h s an

ton khi s dng trong thit k thc t l 2 v khng kh cha 23,2% O 2

theo trng lng v trng lng ring ca khng kh 200C l0,0118KN/m3 = 1,18kg/m3)

Lng khng kh l thuyt cho qu trnh

ngaymO

MM

kk

oxiKK /12.672232.018.1

184

%3

2

=

=

=

Lng khng kh yu cu vi hiu qu vn chuyn E = 8%

phutmphutl

hmngaymngaymE

MM KKEKK

/835.5/5835

/1.350/5.840108.0

/12.672

3

33

3

)(

==

====

Kim tra lng khng kh cn thit cho xo trn hon ton

phutmlm

phutl

W

Mq EKK //48.28

87.204

/5835 33

)( ===

Tr s ny nm trong khong cho php ( ) phmLq ./4020 3=

Lu lng khng kh thit k chn my thi kh

57


58/77

phutlphutmphutmMfQ EKKKK /11670/67.11/835.5233

)( ====

S lng thit b khuch tn kh

Chn thit b khuch tn kh dng a xp , ng knh 170 mm ,

din tch b mt F=0,0227 m2, cng thi kh 200 L/pht.a = 12

m3/gi.a

su ngp nc ca a phn phi kh ly bng chiu su hu ch

ca b H = 4.3 m (t st y b)

S a cn phn phi trong b

dia

diaphl

phutl

I

Qn KK 35.58

./200

/11670===

thun li cho vic b tr u , ta chn s a n = 54 a m vn

m bo hiu sut x l ca b (t theo chiu di 9 a v chiu rng t 6

a, cc a cch nhau 872mm)

p lc cn thit cho h thng nn kh xc nh theo cng thc

mHhhhH fdct c 2.53.45.04.0 =++=+++=

Vihd : Tn tht p lc do ma st dc theo chiu di ng dn, m

hc : Tn tht cc b, m

hf : Tn tht qua thit b phn phi, m

H : Chiu su hu ch ca b, chn H = 4.3m

Tn tht hd v hc thng khng vt qu 0,4m ; tn tht hf khng qu 0,5m

Ap lc khng khat

HP ct 5034.1

33.10

33.10=

+=

Theo cng thc 152 gio trnh X l nc thi ca Hong Hu ta

c cng sut ca my nn kh:

Cng sut my nn kh tnh theo cng thc

( ) ( )KW

qPN 97.27

8.0.102

528.01504.134400

102

134400 29.029.0=

=

=

58


59/77

Vi

q : Lu lng khng kh, q = 0,528m3/s

: Hiu sut my nn kh; = 0,7 0,9 chn = 0,8

Tnh ton ng ng dn kh

ng knh ng phn phi chnh

mmmv

QD

Khi

KK 5.1281285.014.315

1945.044==

=

=

Chn ng st trng km D = 140 mm

Vi

Khiv : Vn tc kh trong ng dn kh chnh , chn smvKhi /15=

KKQ : Lu lng kh cn cung cp , smphutmQKK /1945.0/67.1133 ==

T ng chnh ta phn lm 9 ng nhnh cung cp kh cho b , mi

nhnh t 6 u phn phi kh

Lu lng kh qua mi ng nhnh ( Khong cch gia cc nhnh 872mm).

smphutlphutlQ

Q KKnhanh

/022.0/12979

/11670

9

3===

ng knh ng nhnh

mmmv

Qd

Khi

nhanh 2.430432.014.315

022.044==

=

=

Chn loi ng st trng km d = 45mm

Vi'

khiv : Vn tc kh qua mi ng nhnh smvkhi /15'

=

nhanhQ : Lu lng kh qua ng nhnh

smphutmphutlQnhanh /022.0/297.1/129733 ===

Kim tra li vn tc

Vn tc kh trong ng chnh

sm

D

Qv KKKhi /67.12

14.014.3

1945.04422

=

=

=

59


60/77

khiv nm trong khong cho php (10 -15 m/s)

Vn tc kh trong ng nhnh

sm

d

Qv nhanhKhi /84.13

045.014.3

022.04422

=

=

=

'khiv nm trong khong cho php (10 -15 m/s)

Xc nh lng khng kh cp cho Aeroten Kim tra ti trng th tch LBOD v t s F/M:

Ti trng th tch:

ngaymkgBODkggm

mgngaym

W

LQL aBOD ./962.0/1000*87.204

/197*/1000* 33

33

===

T s F/M:

( )11

6.02.03125.0/3000*

/24

1*5

/197

*/

=== ngayngaylmg

ngayhh

lmg

X

LMF

a

Xc nh kch thc aeroten

Din tch ca aeroten trn mt bng

23

64.473.4

87.204m

m

m

H

WF ===

Vi H : Chiu cao cng tc aeroten, H = 4.3m

Thng s Gi trChiu cao hu ch, m 3.0 4.6Chiu cao bo v, m 0.3 0.6Khong cch t y n u khuch tn

kh, m

0.45 0.75

T s rng : su 1.0 : 1 2.2 : 1

60


61/77

(trang 433 - sch X l nc thi th v cng nghip tnh ton thit

k cng trnh Lm Minh Trit , Nguyn Phc Dn, Nguyn Thanh

Hng)

Bng 5.10: Cc kch thc in hnh cho aeroten xo trn hon ton

Chiu di ca aeroten

mm

B

FL 94.7

6

64.47 2===

Vi B : Chiu rng aeroten, chn B = 6m (B : H = 6 : 4.3 = 1.39 : 1)

Chiu cao xy dng ca aeroten

mhHHbvxd

7.44.03.4 =+=+=

Vi hbv : Chiu cao bo v, chn hbv = 0.4m

Vy kch thc aerotank: Hxd x L x B = 4.7m x 7.94m x 6m

B10) Tnh ton ng dn nc thi , ng dn bn vo b

ng dn nc thi

ng knh ng

mv

QD 122.014.31

0116.044 ===

Chn ng dn nc thi l ng PVC c ng knh 125 mm

Vi

v : Vn tc nc thi chy trong ng , chn smv /1=

Q : Lu lng nc thi , smngaymQ /0116.0/1000 33 =

Kim tra li vn tc nc chy trong ng

smD

Qv /95.0

125.014.3

0116.04422

=

=

=

Tnh ton ng ng dn bn tun hon

ng knh ng dn bn

mv

QD th 133.0

14.35.0

0069.044'

' =

=

=

Vi

61


62/77

thQ : Lu lng bn tun hon ,

smngaymQth /0069.0/60033 =

'v : Vn tc bn trong ng , smv /5.0' =

Chn mmD 140' =

Kim tra vn tc bn:

smD

Qth /448.0

14.0

0069.04422,

,=

=

=

Thng s Gi trChiu di, L 7.94m

Chiu rng, B 6m

Chiu cao cng tc, H 4.3m

Chiu cao bo v, hbv 0.4m

Chiu cao xy dng, Hxd 4.7m

S a phn phi kh 54 a

ng dn kh

ng knh ng chnh

ng knh ng nhnh

140mm

45mm

Thi gian lu nc, 5h

Lu lng bn tun hon, Qth 600m3

/ngy

ng dn nc thi , ng knh D 125mm

ng dn bn tun hon, ng knh D 140mm

Bng 5.11: Bng tm tt chi tit aeroten thit k

62


63/77

5.7. B lng 2

Nhim v ca b lng 2

Lng ton b lng bn sinh ra trong b lng aerotank, ng thi tun hon

lng bn hot tnh cn thit lng quay tr v b aerotank tip tc

qu trnh phn gii cc hp cht hu c. Sau khi qua b lng 2, nc thi

t tiu chun cho php thi vo ngun thi sau khi qua kh trng.

Hm lng BOD sau khi ra khi b lng t 2

70% x 29.6 = 20.72mg/l < 50mg/l.

Hm lng COD sau khi ra khi b lng t 2

70% x 58.85 = 41.895mg/l < 100mg/l.Hm lng SS sau khi ra khi b lng 2

50% x 96.6 = 48.3 mg/l < 100mg/l.

Cc thng s thit k c trng cho b lng t 2 th hin trong

bng:

Loi x l Ti trng b mt

(m3

/m2

ngy)

Ti trng bn

(kg/m2

ngy)

Chiu su

tng cng(m)Trung bnh Ln nht Trung

bnh

Ln nht

Bn hot tnh 16-32 40-48 3.9-5.8 9.7 3.7-6Bn hot tnh

oxygen

16-32 40-48 4.9-6.8 9.7 3.7-6

Aerotank tng

cng

8-16 24-32 0.98-4.9 6.8 3.7-6

Lc sinh hc 16-24 40-48 2.9-4.9 7.8 3-4.5X l BOD 16-32 40-48 3.9-5.8 9.7 3-4.5

Nitrat ha 16-24 32-40 2.9-4.9 7.8 3-4.5

Bng 5.11: Thng s thit k b lng t 2

Din tch mt thong ca b lng t 2 trn mt bng ng vi lu lng

trung bnh tnh theo cng thc

63


64/77

Chn ti trng b mt thch hp cho bn hot tnh ny l 25m3/m2.ngy

)(4025

1000 21

mL

QA

A

tbngay===

Din tch mt thong ca b trn b mt ng vi lu lng ln nht tnh

theo cng thc

)(4538

1700 2max2 mL

QA

A

ngay ===

Trong :

ngayQmax lu lng trung bnh ngy (m3/ngy)

LA : ti trng b mt ln nht (m3/m2.ngy)

Vy din tch b mt b lng tnh theo ti trng bn l

)(3010007.9

3000)258.70()( 2max3

mL

SQQA

S

thrngay=

+=

+

=

Trong

ngayQmax lu lng trung bnh ngy (m3/ngy)

LS: ti trng bn (kgSS/m2.ngy)

Vy din tch b mt theo ti trng bn l din tch tnh ton.

Din tch b mt ng trung tm:

)(8.14504.004.04

2.0

4

2

1

222

mADd

f tt ==

==

ng knh b lng

)(72.7)8.145(4

)(4

1 mfAD =+=+=

ng knh ng trung tm

)(24.172.716.0%16 mDd ===

Chn chiu su hu ch b lng H = 3.5m

Chiu cao lp bn lng hb =1.5m

Chiu cao an ton hbv = 0.3m

64


65/77

Vy chiu cao tng cng b lng t2

Htc = hL + hb + hbv = 3.5m + 1.5m + 0.3m = 5.3m


60% 0.6*3.5 2.1h H m m= = =

Vy kch thc b lng 2: DxH = 7.72 x 5.3 (m)

Kim tra li thi gian lu nc b lng 2Th tch phn lng

( ) ( ) 322222 1605.3*3.172.74

*4

mmmHdDVL ===

Thi gian lu nc

( )h

hm

m

QQ

Vt

r

4.2/6.4125

1603

3

=+

=+

=

Th tch phn cha bn32 5.675.145 mmmhAV bSb ===

Thi gian lu tr bn trong b

h

ngayh

ngaymm

QQ

Vt

thb

bb 64.2

25/24

/5.1293.79

3

3

+

=+

=

Tnh ton mng trn

Chiu di mng trn: L = 0.8 x 7.72m = 6.2 m

Ti trng trn mt mp di mng trn

( )

msmmsl

mlsngayngaymngaymq

./002986.0./986.251.6

/100086400/1)/600/1000(

3

333

==

+=

65


66/77

Chn tm x khe hnh ch V, gc y 90o iu chnh cao mp mng.

Chiu cao hnh ch V l 5 cm, y ch V l 10 cm, khong cch gia cc

nh l 20 cm.

Chiu cao mc nc h trong khe ch V

qo=5

q= 1,4 h5/2

h = mmm 8.440448.04.15

002986.05/2

==

Gi tr ny nh hn tiu chun gii hn cho php (h = 5cm).

Ti b lng 2 c t 2 bm bm bn tun hon v b Aerotank

v v b nn bn

Cng sut ca my bm

. . .

1000

g H QN

=

Trong

Q:lu lng nc thi trung bnh trong ngy,

m3/ngym

H:ct p ca bm, mH2O

: khi lng ring ca cht lng

o Nc: = 1000kg/m3

o Bn: = 1006 kg/m3

g: gia tc trng trng, g = 9,81 m/s2

: hiu sut ca bm, = 0,730,9

chn = 0,8

Ct p ton phn ca my bm bn tun hon v b Aerotank

H = 1.8m +4.7m = 6.5m

66


67/77

Cng sut ca my bm bn tun hon:

KwgHQ

N 557.0864008.01000

81.910066005.6

1000=

==

Cng sut thc t ca bmkwN 84.0557.05.1 ==

Ct p ton phn ca my bm bn d v b nn bn

H = 1.8m + 3.3m = 5.1m

Cng sut ca my bm bn d

KwgHQ

N 0091.0864008.01000

81.910065.125.6

1000 =

==

Cng sut thc t ca bm

kwN 0136.00091.05.1 ==

5.8. B kh trng.

Nhim v ca b kh trng

Nc thi sau khi qua qua trnh x l sinh hc, cn mang theo mt lng

vi khun theo nc thi ra ngoi. Do b kh trng c nhim v tiu dit

lng vi khun trc khi a nc ra ngun tip nhn.

Nc thi Liu lng, mg/lNc thi sinh hot lng s

b

Nc thi kt ta bng ho cht

Nc sau x l b lc sinh hcNc sau x l bn hot tnh

Nc thi sau lc ct

5 10

3 10

3 102 8

1 5

(Ngun: trang 467, X l nc thi cng nghip v th,

Lm Minh Trit)

Bng 5.12: Liu lng chlorine cho kh trng

Thng s Gi tr

67


68/77

Tc dng chy, m/pht

Thi gian tip xc, pht

T s di / rng, L/W

2 4,5

15 30

10 : 1

(Ngun: trang 468, X l nc thi cng nghip v th,

Lm Minh Trit)

Bng 5.13: Cc thng s cho b tip xc chlorine

Chn thi gian lu nc pht15=

Liu lng clo dng l 33 mgc =

Th tch b l :

( )34.1060

156.41 mQV TBngy ===

Chn vn tc chy trong b l ( )phtmv 5,2=

Tit din ngang ca b tip xc l :

( )228,0605,2

6.41m

v

QA =

==

Gi s chiu su tip xc ca b l mH 6,0= , th chiu rng ca b l

( )mH

AW 47,0

6,0

28,0===

Chiu di tng cng ca b

( )mHW

VL 88,36

47,06,0

4.10=

==

Vy ta chn W x L = 0,47 m x 36,88 m

Kim tra t s L/W: L/W = 36,88 : 0,47 = 78,46 > 10, do chn kch

thc ca b t yu cu.

gim chiu di xy dng, chia b lm 5 ngn chy theo hng ziczac,

mi ngn 0,3m vy chiu di b c tnh

( ) ( )mWH

VL 4,747,056,0

4,10

5 ===

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Vy kch thc b tip xc 6,047,04,7 = HWL

Lng chlorine tiu th trong mt ngy m l

( ) demngaykgdemngaygcQM ./3./300031000 ====

5.9 B nn bn trng lc

Nhim v ca b nn bn trng lc

Bn hot tnh d ngn lng c m cao, cn phi t n d mthch hp xy dng trc khi cho qua cc cng trnh s l tip theo hoc

thi ra mi trng lm phn bn (nu lng cn ti t).

Dng cha lng bn d t b lng 1, b UASB, v b lng 2.

Lu lng bn thu t b lng 1: ngaymQtuoi /747.13=

Lng bn ti l: ngaykgSSMtuoi /92=

Lu lng bn thi ra b UASB c bm vo b cha bn

l: ngaymQW /56.03=

Lng bn thi ra khi b UASB

ngayKgSSMss /6.12=

Lu lng bn thi b b lng 2 c a vo b cha bn

vi ngymQb /5.123=

Lng bn thi b trong b lng 2

ngaykgSSXQM thbb /10085.12 ===

Vi X th =8000mg/l:Nng VSS trong bn thi.

Tng lng bn

M = 92+12.6+100 = 204.6 kgSS/m3

Vy tng lu lng bn vo trong b cha bn l

Qnen = 1.747 + 0.56 + 12.5 = 14.807m3/ngy.

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Din tch b nn bn

241.360

6.204m

a

MA ===

Vi a: ti trng ring ca hn hp bn b lng 1 v bn hot tnha = (50-70)kgSS/m2.ngy. Chn a = 60kgSS/m2.ngy

Din tch b mt ng trung tm

2222

1364.014.304.004.04

2.0

4mA

Ddf tt ===

=

=

ng knh ca b nn bn

mfAD 125.2)1364.041.3(4)(4 =+=+=

ng knh ng trung tm

d = 16%D=0.16 x 2.125 = 0.34 m

Chn chiu cao vng nc trong v vng vo l h= 2m

Chn chiu cao vng nn bn l hnn= 1m

Chn chiu cao bo v l hbv= 0.3m

Vy chiu cao b nn bn: H= 3.3m


h = 60%H = 0.6 x 3.3 = 2 m

Kch thc b nn bn: DxH= 2.125 x 3.3 m

Thi gian lu nc

ngayQ

HA

Q

Vt 7.0

807.14

3.341.3=

=

==

Ti b nn bn c t 1 bm bm bn v sn phi ct

H = 4.3 + 0.3 = 4.6 m

Cng sut ca my bm bn

KwgHQ

N 0097.0864008.01000

81.91006807.146.4

1000=

==

Cng sut thc t ca bm

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kwNNtt 015.05.10097.05.1 ===

= 0.2 HP

5.10 My p bn dy ai

Nhim v ca my p bn dy ai

Gim m, th tch ti a ca bn cn trc khi thi ra mi trng. Cn

thi b c th c s dng lm phn bn hoc thi b hp v sinh.

Lng bn cn p mi ngy

M = 96% x 204.6 = 196.42 kgSS/ngay

Nng bn sau khi p : 18%

Khi lng bn sau p

)/(36.35100

1842.196ngayKg=

S gi hot ng : 8h/ngy

Ti trng bn tnh trn 1m chiu rng bng p l 90kg/m.h

Chiu rng bng p

( )m273.090842.196 =

Chn 1 thit b lc p dy ai b rng bng l 0,5m

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PHN 6: TNH KINH T

6.1. Chi ph u t xy dng

STTTn cngtrnh

ThTch(m3)

SLng(ci)

ngi(ngVN)

Thnhtin(ngVN)

1Song Chnrc 1 8,000,000 8,000,000

2 B lng ct 2.5 2 1,500,000 7,500,000

3 Sn phi ct 3.8 1 1,500,000 5,700,000

4 B iu ha 52 1 1,500,000 78,000,000

5 B lng 1 38.3 1 1,500,000 57,450,000

6 B UASB 20.12 5 1,500,000 150,900,000

7BAEROTANK 35.65 1 1,500,000 53,475,000

8 B lng 2 56.3 1 1,500,000 84,450,000

9 B nn bn 12.3 1 1,500,000 18,450,000

10 B kh trng 3.68 1 1,500,000 5,520,000

11 My p bn 1 1 444 000 000 444 000 000

12

Cc cngtrnh kmtheo(nglng) 50 000 000 50 000 000

Tng cng 962 445 000

Bng 6.1: Gi vt liu xy dng

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Tn vt t Chi tit S lng n gi Thnh tin

Bm

Bm Nc t b iu ha

sang lng 1

H = 4.8m

Q = 41.16m3/h

N = 1.02 kw

= 1.37 HP

2 12 000 000 24 000 000

Bm bn

Tun hon v

aerotank ti

b lng 2

H = 6.5 m

Q = 25m3/h

N = 0.84kw

=1.13 HP

2 9 000 000 18 000 000

Bm bn v

b nn bn

H =5.1m

Q=0.52m3/h

N=0.0136kw

=0.02HP

2 8 000 000 16 000 000

Bm bn ti

b nn bn

H = 4.6m

Q=0,62m3N=0.02HP

2 8 000 000 16 000 000

Bm inh

lng2 11 000 000 22 000 000

ng

ng(ng dn

bn, ng dn

nc thi,ng dn kh)

200 000 000 200 000 000

H thng

in ng lc

v chiu sng

50 000 000 50 000 000

My thi kh2 50 000 000 100 000 000

a thi kh 54 880 000 47 520 000

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Tn vt t Chi tit S lng n gi Thnh tin

Tng cng 493 520 000

Bng 6.2: Gi trang thit b ph

Tng tin u t

(962 445 000+ 493 520 000) x 1.3 = 1 892 754 500 (VN ng)

6.2. Chi ph vn hnh trm

6.2.1. Lng ho cht s dng

Tn ho

cht

Liu

lng

Nng

S dng n gi Thnh tin

NaOCl 10 mg/l 10% 4kg/ngy 2.300 /kg 9.200

Bng 6.3: Lng ha cht cn dng

Chi ph ho cht cho 1m3 nc: 9.200 1000 m3 = 9 ng/m3

6.2.2. Chi ph in

c tnh : 600kW/ngy

in nng tiu th tnh cho 1m3 nc

600 kw/ngy 1000 m3 = 0,60 kw/m3

Gi cung cp in cng nghip: 980 ng/kw

Chi ph in tnh cho 1 m3 :

980 ng/kw 0,6 kw/m3 = 588 ng/m3.

6.2.3. Chi ph nhn cng

S lng nhn vin : 4 ngi

Mc lng thng: 2.500.000 ng/ngi.thng

Chi ph tng cng : 4 ngi 2.500.000 ng/thng = 10.000.000

ng/thng

Chi ph nhn cng tnh cho 1m3 nc

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10.000.000 / 30 x 1000 = 333 ng/m3

6.2.4. Chi ph vn hnh trm x l

Phn loi chi ph Chi ph n v, ng/m3

Chi ph ho cht 9

Chi ph in 588

Chi ph lng 333

Cng 930

Bng 6.4. Bng phn tch chi ph

6.3. Gi thnh x l mt m3 nc thi

Tng chi ph u t: S = 1 892 754 500 (VNng)

Gi thnh mt m3 nc thi

930 ng/m3 + 1 892 754 500/(Q x 365 x 10) = 1 500 000 (VN ng)

vi nin hn s dng : 10 nm

Vy chi ph 1m3 nc thi l 1.500 ng /m3

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PHN 7: KT LUN

Tm li vic x l nhim l v cng cp bch v c ngha quan

trng trong s pht trin bn vng ca cc ngnh sn xut ni chung, v

ca ngnh ch bin thy hi sn ni ring. Trn c s nghin cu v thnh

phn v tnh cht ca nc thi thy hi sn nhm chng ti ting hnh

a ra quy trnh cng ngh x l nh trn. V hiu qu x l t c l

sau khi x l nc thi t tiu chun loi B ca nc thi cng nghip

(TCVN 5945-2005) v iu kin thi ra ngoi mi trng.

Chi ph cho vic x l 1m3 nc thi l 1.500 ng. V vy, vic xy

dng trm x l nc thi l kh thi v chp nhn c.

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TI LIU THAM KHO

1. Lm Minh Trit, X l nc thi th v cng nghip tnh ton

thit k cng trnh, NXB HQG, 2006.

2. Trnh Xun Lai, Nguyn Trng Dng, X l nc thi cng

nghip, NXB Xy Dng H Ni, 2005.

3. Trnh Xun Lai, Tnh ton thit k cc cng trnh x l nc thi,

NXB Xy Dng.

4. Nguyn Xun Hon, L Th Ngc Diu, Ti liu x l nc cp

5. Tiu Chun xy dng TCXD 51 84.

6. Mt s n x l nc thi ca Nguyn Thi Anh, Trn Thanh T,

L Hng Qun.

do an xu ly nuoc thai nha may che bien thuy san 504

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