Đồ án tốt nghiệp đã hoàn thành

8/8/2019 n tt nghip hon thnh

1/100

Thit k h thng x l nc thi cho d n nng cng sut ca Cng ty c phn bia Si Gn Min Trung ln 100 triu lt bia/nm L Trng n Lp CNMT-K50-QN.

LI NI UTrong nhng nm gn y nn cng nghip th gii ni chung v Vit Nam

ni ring pht trin khng ngng. Kinh t pht trin, thu nhp c nng cao, sng ngi dn c ci thin Tuy nhin, bn cnh nhng thnh tu t c t

chng ta ang phi i mt vi mt vn mang tnh ton cu v e da n ssng, l vn nhim mi trng. Hin nay, vn nhim mi trng antr nn rt bc xc khng nhng cho mi quc gia m cn cho ton nhn loi, trong hot ng sn xut cng nghip c xc nh l mt trong nhng nguyn nh nhim chnh. V vy vn bo v mi trng l vn ton cu, l quc sca hu ht cc quc gia trn th gii.

Trong giai on hin nay, s ton cu ha v hp tc quc t cng nhau phtrin l rt cn thit cho mi quc gia vVit Nam cng khng nm ngoi xu th .Tuy nhin, chng ta cng ang ng trc nhng thun li v thch thc. Mttrong nhng thch thc ln nht l vn mi trng. Chnh ph Vit Nam rquan tm n vn ny nn ban hnh nhiu vn bn php lut nh: lut bo vmi trng (1994), ngh nh 26/CP ngy 26/4/1996 ca Chnh Ph v x pht hnhchnh v lut mi trng sa i b sung (2006) nhm qun l v bo v mtrng tt hn. Chng ta gia nhp WTO (11/1/2007) th vn mi trng l vcng quan trng; n c th quyt nh n thnh cng hay tht bi ca mt doan

nghip.Trong xu th pht trin chung , ngnh cng nghip Ru- Bia- Nc giikht, khng nhng va mang li li nhun cao m cn ng gp ng k (hn 5000t ng) cho ngn sch ca nh nc. V th, nh my bia Si Gn - Min Trung,c xy dng ti khu cng nghip Ph Ti - Thnh ph Quy Nhn - Tnh Bnhnh, cng sut ti a 50 triu lt/nm c k hoch m rng ln 100 triu lt/nmtrong tng lai. Nh my s gp phn gii quyt vic lm cho cc lao ng, khngch lao ng trc tip trong nh my m cn cc lao ng cc mng li phn

phi v tiu th sn phm; ng thi ng gp mt phn khng nh cho ngn scnh nc. Tuy nhin, bn cnh nhng li ch to ln, cc loi cht thi (c bit lnc thi) pht sinh t hot ng sn xut ti nh my c tc ng tiu cc ti hsinh thi v mi trng xung quanh. Do , vn quan tm nht l ngun nthi t qu trnh sn xut bia cn phi c x l mt cch hiu qu.

Vi nhng l do trn, ti Thit k h thng x l nc thi cho d n nng cng sut ca Cng ty C phn bia Si Gn - Min Trung ln 100 triu lt bia/nm c la chn lm n tt nghip.

Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.386935511


2/100


CHNG ITNG QUAN V CNG NGH SN XUT BIA, CC CHT THI T

CNG NGH SN XUT BIA V HIN TRNG X L

I.1. TNG QUAN V CNG NGH SN XUT BIAI.1.1. Tnh hnh sn xut, tiu th Bia trn th gii v Vit Nam I.1.1.1. S lc v Bia

nh ngha bia ca Php:Bia l mt loi ung thu c t qu trnh lnmen dch cc cht chit t i mch ny mm, c b sung khng qu 15% nguynliu ng khc v hoa houblon. [1]

nh ngha bia ca c:Bia l mt loi ung thu nhn c nh lnmen, khng qua chng ct v ch s dng i mch ny mm, hoa houblon, nmmen v nc. [1]

nh ngha Bia ca Vit Nam:Bia l loi ung ln men c cn thp,c lm t nguyn liu chnh l malt i mch, houblon, nm men v nc.[1]

Bia l loi nc gii khc c truyn thng lu i, c gi tr dinh dng caov c cn thp, mi v thm ngon v b dng. Ung bia vi mt lng thchp khng nhng c li cho sc khe, n cm ngon, d tiu ha m cn gim s mt mi sau ngy lm vic mt nhc. Khi i sng kinh t x hi pht trin nh

cu tiu th bia ca con ngi cng tng.So vi nhng loi nc gii kht khc, bia c cha mt lng cn thp (3 8%), v nh c CO2 trong bia nn to nhiu bt khi rt, bt l c tnh u vit ca bia.

V mt dinh dng, mt lt bia c cht lng trung bnh tng ng v25g tht b hoc 150g bnh m loi mt, hoc tng ng vi nhit lng l 50kcal. V vy bia c mnh danh l bnh m nc.[1]

Ngoi ra trong bia cn c vitamin B1, B2, nhiu vitamin PP v axit amin rt

cn thit cho c th. Trong 100ml bia 10% cht kh c: 2,5 5 mg vitamin B1, 35 36 mg vitamin B2 v PP [1]. Chnh v vy t lu bia tr thnh th ung quenthuc c rt nhiu ngi a thch.

Nc ta c kh hu nhit i, dn s tng i ln, hn 83 triu ngi v ct l dn s tr chim a s nn tim nng tiu th nc gii kht ni chung v bni ring l rt ln, cn c khai thc.

Thc t, ngnh cng nghip bia nc ta ngy cng pht trin mnh v cnhng bc tin ng k v s lng v cht lng. Thnh cng ca ngnh bkhng nhng ng gp mt t trng khng nh vo ngn sch nh nc m cn gp phn to cng n vic lm cho hng vn lao ng. [1]Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.386935512


3/100


I.1.1.2. Tnh hnh sn xut v tiu th bia trn th gii i vi cc nc c nn cng nghip pht trin, i sng kinh t cao th bi

c s dng nh mt th nc gii kht quan trng.Hin nay, trn th gii c 25 nc sn xut bia vi tng sn lng trn 10

t lt/nm, trong : M, c, mi nc sn xut trn di 10 t lt/nm; TrungQuc 7 t lt/nm (bng 1.1).

Thng k bnh qun mc tiu th hin nay mt s nc cng nghip tintin nm 2004 nh sau: Cng ha Czech hn 150 lt/ngi/nm; c 115lt/ngi/nm; M trn 80 lt/ngi/nm (bng 1.2).

Bng 1.1. Sn lng bia cc nc (triu lt)[1]Quc gia 2002 2003 2004 2005

M 23300 23340 23440 23270c 10840 10550 10580 10580 Nga 7390 7560 8420 8840Brazin 8500 8300 8260 8500Mexico 6400 6640 6200 6300Anh 5670 5800 5880 5890Ty Ban Nha 2790 2970 3020 3020Ba Lan 2600 2730 2800 2850Canada 2200 2300 2320 2320H Lan 2490 2510 1920 2190

Bng 1.2. Tnh hnh tiu th bia trn th gii nm 2004[1]

Quc giaXp hng

nm2004

Tng lngtiu th (triu

lt)

Bnh qunu ngi

(lt)

T l tng sovi nm 2003

Trung Quc 1 28640 22,1 14,6%M 2 23974 81,6 0,9%c 3 9555 115,8 -1,6%Brazin 4 8450 47,6 2,8% Nga 5 8450 58,9 11,1% Nht 6 6549 51,3 0,7%Anh 7 5920 99,0 -1,8%Mexico 8 5435 51,8 2,0%Ty Ban Nha 9 33,76 83,8 0,9%Ba Lan 10 26,70 69,1 -2,4%CH Czech 15 18,78 156,9 2,1%

Tng lng tiu th trn th gii nm 2003 khong 144,296 t lt, nm 2004khong 150,392 t lt (tng 4,2%).

Bng 1.3. Phn chia lng bia tiu th theo vng [1]Vng Lng bia tiu th (%) V th



4/100


Chu u 32,8 1Chu 28,7 2Bc M 17,4 3Trung / Nam M 14,4 4Chu Phi 4,7 5a Trung Hi 1,4 6Trung ng 0,6 7

Lng bia tiu th tng hu ht khp cc vng, ngoi tr vng a TrungHi, y lng tiu th bia trn th gii tng ln. Nhng lng tng ng k nhtTrung Quc vi tc tng n 14,6% (bng 1.2).

Chu l mt trong nhng khu vc c lng bia tiu th tng nhanh, ccnh nghin cu th trng bia ca th gii nhn nh rng Chu ang dn gi v

tr dn u v tiu th bia trn th gii.Trong khi sn xut bia Chu u c gim, th Chu , trc kia nhiu

nc c mc tiu th bia theo u ngi thp, n nay tng bnh qun6,5%/nm. Thi Lan c mc tng bnh qun cao nht 26,5%/nm; tip n lPhilippin 22,2%/nm; Malaysia 21,7%/nm; Indonesia 17,7%/nm. y l nhngnc c tc tng nhanh trong khu vc. Cc nc xung quanh ta nh Singaport 18 lt/ngi/nm, Philippin 20 lt/ngi/nm (theo s liu ca Vin ru bi NGK Vit Nam).

Th trng bia Nht Bn chim 66% th trng bia khu vc vi 30,9 t USDLng bia tiu th nm 2004 t trn 6500 triu lt (theo ngun t Kirin news Nht Bn)

Th trng bia ca Trung Quc pht trin l nguyn nhn ch yu thc ys tng trng ca ngnh cng nghip bia Chu . n nm 2004, tng lng bitiu th Trung Quc l 28.640 triu lt, xp th hng u tin trn th gii.

Tng lng bia tiu th cc nc khu vc Chu trong nm 2004 t43.147 triu lt, tng 11,2% so vi nm 2003. [1]

Quy m sn xut bia ca nh my chnh sch th trng Trong cng nghip sn xut bia, quy m sn xut mang ngha kinh t rt

ln. Chnh v vy, ti cc th trng m tha mn c nhu cu nh M, Nht ms hng bia siu ln thng lnh th trng: Th trng M do 5 cng ty kim sotcn Nht do 4 cng ty kim sot chim 40% th phn, ti Canada 94% th trng do2 cng ty kim sot [1].

Ti Trung Quc, trong s hn 800 nh my bia th 18 nh my c cng sut

ln hn 150 triu lt/nm v sn xut 2.500 triu lt/nm, chim sn lng biaca c nc.



5/100


Do th trng bia trn th gii ang pht trin mt cch nng ng, cc hng bia s dng cc chin lc kinh doanh khc nhau.

Ti M v Chu u, do th trng bia n nh, chin lc kinh doanh bial dnh th phn, gim chi ph sn xut. Ngc li, ti Trung Quc l ni th trn

ang tng trng th chin lc l pht trin sn xut, tng sn lng v nng cacht lng.

Ngoi ra cn phi xy dng nh my bia phn tn nhiu vng nhm thu htngi tiu dng.

I .1.1.3. Tnh hnh sn xut v tiu th bia Vit NamBia c a vo Vit Nam t nm 1890 cng vi s c mt ca Nh my

Bia Si Gn v Nh my Bia H Ni, nh vy ngnh bia Vit Nam c lch shn 100 nm.

Hin nay, do nhu cu ca th trng, ch trong mt thi gian ngn, ngnh snxut bia c nhng bc pht trin mnh m thng qua vic u t v m rng cnh my bia c t trc v xy dng cc nh my bia mi thuc Trung ng va phng qun l, cc nh my lin doanh vi cc hng nc ngoi. Cng nghip bia pht trin ko theo s pht trin ca cc ngnh sn xut khc v hng nmngnh bia ng gp cho ngn sch nh nc mt lng ng k.

Tnh hnh sn xut bia trong nc

Do tc ng ca nhiu yu t nh tc tng trng GDP, tc tng dns, tc th ha, tc u t m ngnh cng nghip Bia pht trin vi t tng trng cao. Chng hn nh nm 2003, sn lng bia t 1290 triu lt, tn20,7% so vi nm 2002, t 79% so vi cng sut thit k, tiu th bnh qun ngi t 16 lt/nm, np ngn sch nh nc khong 3650 t ng. [1]

V s lng c s sn xut S lng c s sn xut gim xung so vi nhng nm cui thp nin 199

n nm 2003 ch cn 326 c s sn xut so vi 469 c s nm 1998 [1]. iu n

l do yu cu v cht lng bia, v mc v sinh an ton thc phm ngy cncao, ng thi do s xut hin ca nhiu doanh nghip bia ln c thit b v cnngh tin tin nn c s cnh tranh gay gt, nhiu c s sn xut quy m nhcht lng thp khng kh nng cnh tranh ph sn hoc chuyn sang sxut sn phm khc.

Trong cc c s sn xut , Sabeco c nng sut trn 200 triu lt/nm,Habeco c nng sut hn 100 triu lt/nm, 15 nh my bia c nng sut trn 15triu lt/nm v khong 165 c s sn xut c nng sut di 1 triu lt/nm.



6/100


1.3 1.4 1.51.6

2

3

4.7

6

0

1

2

3

4

5

6

7

2003 2004 2005 2006 2008 2010 2015 2025

Nm

T l t

Hnh 1.1. th biu din sn lng bia c nc qua cc nm[2].V mc tiu th bia

Hai Tng cng ty Sabeco v Habeco c ng gp tch cc v gi vai tr cho trong ngnh bia. Ring nm 2003, doanh thu ca ngnh Bia- Ru- NGK Vit Nam t 16.497 t ng, np ngn sch nh nc 5000 t ng, to iu kin vilm v thu nhp n nh cho trn 20.000 lao ng. Sn lng tiu th bia ton qut 1290 triu lt chim 78,8% cng sut thit k, trong Habeco v Sabeco 472,28 triu lt (chim 36,61% ton ngnh bia) [1].

Mc tiu th bnh qun u ngi Vit nam tng ln nhanh chng trongvng 10 nm qua, t mc di 10 lt/ngi/nm nm 1997 tng ln 18lt/ngi/nm vo nm 2006, d kin n nm 2015 l 35 lt/ngi/nm.

10.5 11 11.512.5 13.25

14 1516 16.83

18

28

35

0

5

10

15

20

25

30

35

40

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2010 2015

Nm

l t / n g i

Hnh 1.2. th biu din mc tiu th bnh qun u ngi qua cc nm [2].nh hng pht trin nn cng nghip bia Vit Nam n nm 2020Do mc sng ngy cng tng, mc tiu th ngy cng cao khng k cc nc

Chu u, Chu M c mc tiu th bia theo u ngi rt cao do c thi quen ung

bia t lu i, cc nc Chu tiu dng bnh qun 17 lt/ngi/nm [1].



7/100


Truyn thng vn ha dn tc v li sng tc ng n mc tiu th bia,ru. cc nc c cng ng dn tc theo o hi, khng cho php gio dn unru bia nn mc tiu th bnh qun theo u ngi mc thp. Ti Vit Namkhng b nh hng ca tn gio trong tiu th bia nn th trng cn pht trin.

Nm 1995 dn s Vit Nam l 74 triu ngi, nm 2000 khong 81 triungi v hin nay trn 83 triu ngi. Do vy d kin mc tiu th bnh qun theu ngi vo nm 2010 l 28 lt/ngi/nm, sn lng 3 t lt/nm v n nm2015 mc tiu th bnh qun l 35 lt/ngi/nm vi sn lng 6 t lt/nm. [2]

I.1.2. Tng quan chung v cng ngh sn xut bia I.1.2.1. c trng nguyn liu sn xut bia

Bn loi nguyn liu chnh khng th thiu trong qu trnh sn xut bia l:malt i mch, hoa houblon, nc v nm men. Cht lng ca chng quyt nn cht lng ca bia thnh phm. Hiu bit y cc tnh cht ca nguyn litc dng ca chng i vi qu trnh sn xut v sn phm bia l c s ca qu trniu hnh sn xut v x l, t c th iu hnh qu trnh cng ngh mt cchp l nht.

1. Malt i mch v go t- Malt i mch

Cha hm lng tinh bt ln, v dnh rt chc vo ht. Ht la mch

x l bng cch ngm ht vo trong nc, cho chng ny mm n mt giaon nht nh v sau lm kh ht ny mm trong cc l sy nhm thu hng cc mch nha ha (malt). Mc tiu ch yu ca quy trnh ny l hot hatch ly v khi lng v hot lc ca h enzym trong i mch.

Hm lng m trung bnh ca i mch thng l 14 14,5%. Hm lngm c th bin thin t 12% trong iu kin thu hoch kh ro n trn 20% troniu kin m t. i mch c m cao cn c sy kh bo qun cv khng lm mt kh nng ny mm.

Hm lng trung bnh ca cc thnh phn tnh theo khi lng cht kh nhsau: [1]

- Cacbonhydrat tng s 70 85%- Protein 10,5 11,5%- Cc cht v c 2 4%- Cht bo 1,5 2%- Cc cht khc 1- 2%

- Go t



8/100


Vit Nam, go t thng c dng lm nguyn liu thay th km theomalt h gi thnh sn phm. T l go khong 20 30%. Go t l ngun nguyliu d kim, khng cn nhp ngoi.

Thnh phn v tnh cht ca go t nh sau: [3]

- Hm m 12%- ha tan 76%- Tinh bt 75%- Cht bo 1 1,5%- Protein 8%- khong 1 1,2%- X 0,5 0,8%

2. Hoa Houblony l thnh phn rt quan trng v khng th thay th c trong quy trnh

sn xut bia, gip mang li hng thm v v ng rt c trng, lm tng kh nnto bt, tng bn keo v n nh thnh phn sinh hc ca sn phm.

Bng 1.4. Thnh phn ca hoa Houblon[1]Thnh phn Hm lng (%)

Nc 10 11 Nha ng tng s 15 20Tinh du 0,5 1,5Tanin 2 5Monosaccarit 2Pectin 2Amino axit 0,1Protein 15 17Lipit v sp 3Cht tro 5 8Xenluloza, lignin v cc cht khc 40 50

Cc ch phm ca hoa houblon: Hoa vin v hoa cao.3. NcCng ngh sn xut bia i hi mt lng nc rt ln nh ngm

mch trong sn xut malt, h ha, ng ha, ra men, ra thit b, cung cp cho lhi

Thnh phn v tnh cht ca nc nh hng trc tip n ton b qu trncng ngh v cht lng bia thnh phm.

Bng 1.5. Yu cu i vi nc dng trong sn xut bia[1]

Thnh phn n v Hm lng pH 6,5 7



9/100


cng oH 5 12Mui Cacbonat mg/l 50Mui Mg2+ mg/l 100Mui clorua mg/l 75 150CaSO4 mg/l 150 200 NH3 v mui NO2 mg/l Khng cSt Fe2+ mg/l < 0,3Vi sinh vt T bo/ml < 100

Trong qu trnh sn xut bia, cn phi lu mt vi im nhy cm khi ntip xc vi dch ng, nm men v bia:

- Nc ra b cn phi iu chnh kim < 50 mg/l v pH = 6,5 khchit cc cht khng mong mun t b. pH ca dch ng trc khi nu nn

l 5,4 thu c dch ng sau khi nu c pH = 5,2. [1]- Nc c ra v ra nm men phi c tit trng v kh mi l.- Nc pha long bia phi c nhng c tnh sau:

+ Hm lng oxy ha tan < 0,05mg/l+ Hm lng CO2 > hm lng CO2 trong bia nn cn pha long+ Hm lng, thnh phn khong tng ng vi bia+ Khng c vi sinh vt v mi l.

4. Nm men

Nm men l loi vi sinh vt n bo, c kh nng sng trong mi trngdinh dng cha ng, nit, photpho, v cc cht hu c, v c khc. Chng l vsinh vt d dng c kh nng sng trong c hai mi trng hiu kh v ym kh.

Nm men ng vai tr quyt nh trong sn xut bia v qu trnh trao i chtca t bo nm men bia chnh l qu trnh chuyn ha nguyn liu thnh sn phmQu trnh chuyn ha ny gn lin vi s tham gia ca h enzym trong t bo nmmen. Do , vic nui cy nm men thu c mt h enzym c hot lc cao mt khu ht sc quan trng.

Hai chng nm men thng c s dng trong sn xut bia l nm men nSacharomyces cerevisiaev nm men chmSacharomyces carlsbergensis.[3]

5. Cc nguyn liu ph khc:[1]- NaOH: dng trung ha v v sinh, ty ra (CIP)- Axit: HCl, H2SO4 dng iu chnh pH nc v x l men sa. Ngoi ra

cn s dng axit lactic, axit nitric, axit photphoric iu chnh dch hm trong qu

trnh nu v ng ha, v sinh ty ra v st trng.- Mui, cht tr lc v mt s cht kh, enzym.



10/100


I.1.2.2. Quy trnh cng ngh sn xut bia(hnh 1.3)Thuyt minh s cng ngh:- Nguyn liu c kim tra cht lng, s lng v a vo nhp kho. The

cng thc phi liu s chuyn sang xay, nghin nh, to iu kin cho cc cn

on sau c thc hin d dng v trit .- Bt go sau khi c xay nh s ha trn vi nc v em gia nhit n

chn. Tip theo cho bt malt vo gia nhit, thc hin ng ha. Trong mi trnggiu nc, cc hp cht s c thy phn di s xc tc ca enzym, trong quan trng nht l s thy phn tinh bt, protein v cc hp cht cha photphoChim nhiu nht v khi lng trong thnh phn ca cc sn phm t qu trnny l ng Dextrin.

- Lc b b, thu hi dch ng. Lc dch ng thu nc nha trong v lo b b. Qu trnh lc c tin hnh theo hai bc: bc u tin p tch dch cv bc th hai l ra b chit rt ht tt c nhng phn dinh dng cn bm .

- Cho hoa vo dch ng un si; di tc dng ca nhit, cc cht khng hatan ca hoa c ha tan chuyn ha vo dch ng to hng, v c trng ch bia.

Qu trnh Houblon ha nhm to mt s yu t quan trng cho bia nh trch

ly cht ng, tinh du thm bin i thnh dch ng c v ng v hng thdu ca hoa c trng c bn v tnh cht cm quan ca bia sau ny: to cht kt lng cc ht nh li ti trong dch ng; to cc hp cht tham gia vo qu trnto bt v l tc nhn chnh gi bt cho bia.

- Dch ng sau houblon ha c tch cn, chuyn dch v men vo Tank ln men thc hin qu trnh ln men chuyn ng thnh ru. Qu trnh ln menc thc hin nhit thp to iu kin cho men hot ng. V vy, cn pc giai on lm lnh nhanh dch ng trc khi thc hin ln men.

Ln men l giai on quan trng nht trong sn xut bia, quyt nh chuyn ha dch ng houblon ha thnh bia di tc dng ca men.

C6H1206 ---> 2C2H5OH + 2CO2 - QR



11/100


Hnh 1.3. Cng ngh sn xut bia km theo cc dng thi[8].

- Lc bia nhm loi b cc cht khng tan nh nm men, protein, houblon lmcho bia trong hn trn my lc p khung bn vi cht tr lc l diatomit. Tip theo

bia c bo ha CO2 v a i chit chai, bock, lon- Trong bia thnh phm, sn xut theo cc phng php thng thng lun


Chun b nguyn liu

Nu ng ha

Lc dch ng

Lc, tch b

Nu hoa Houblon

Ln men chnh, ph

Lc trong bia

Chit bia

Bo ha CO2

ng np

Thanh trng

Lm lnh

Kim tra-dn nhn-nhp kho

Sn phm

Malt Go Nc mm

Ra chai

Hi Xt

chai

Hi nc

Cht tr lc

Ra menging

Phc himen

Hi ncHoa houblon

Hi nc

Ph gia

B malt

B hoa+ malt

B men

Sc kh

B lc

Bia hi

L hi

Men ging

Nn CO2

11

Nc ra sn,thit b

Nc thi


12/100


lun cha cc t bo cn sng, bao gm nm men thun chng v cc vi sinh vt lkhc. Do , thanh trng l gii php quan trng dit vi sinh vt nhm nng cao bn sinh hc cho sn phm.

C 2 phng php thanh trng bia: thanh trng c khi i vi bia hi v

thanh trng trong bao b i vi bia chai, lon.- Sau khi thanh trng, bia hi c chit kt vn chuyn n cc c s tiu

th ngay trong ngy; cn bia chai s c chuyn n khu dn nhn, nhp kho chxut xng.I.2. CC CHT THI T CNG NGH SN XUT BIA V HIN TRNG

X LI.2.1. Nc thi

I.2.1.1. Ngun gc pht sinh, c tnh nc thi cng nghip sn xut biaCng nghip sn xut bia l mt trong nhng ngnh cng nghip i hi tiu

tn mt lng nc ln cho mc ch sn xut v v th s thi ra mi trng mlng nc thi ln. C th nh sau: [1, 4]

Nc lm lnh, nc ngng, y l ngun nc thi t hoc gn nh khngy nhim nn c kh nng tun hon s dng li.

Nc thi t cng on nu - ng ha: bao gm- Nc thi trong qu trnh ra b sau nu,- Nc thi do v sinh ni nu go, malt, hoa; v sinh thit b lc dch nv thit b tch b.c tnh ca nc thi ny c mc nhim rt cao, c cha b malt, bhoa, tinh bt, cc cht hu c, mt t tanin, cht ng, cht mu

Nc thi t cng on ln men: Nc v sinh cc tank ln men, thng cha, ng ng, sn nh c cha b men, bia cn v cc cht hu c.

Nc thi t cng on hon tt sn phm: Lc, bo ha CO2, chit chai,ng np, thanh trng. Nc thi ch yu t cng on ny l nc v sin

thit b lc, nc ra chai v tc cha. y cng l mt trong nhng dngthi c nhim ln trong sn xut bia. Nc thi t cng on ny c cha bt tr lc, mt t b men, bia cn li t bao b ti s dng, bia ri vi trong qu trnh chit, pH cao

Nc ra sn cc phn xng, nc thi t ni hi, nc t h thng llnh c cha hm lng chlorit cao.

Xt v axit thi ra t h thng CIP, xt t thit b ra chai. Dng thi ny clu lng nh v cn thu hi ring x l cc b, tun hon ti s dn

cho cc mc ch khc.



13/100


Bn cnh nc thi sn xut, mt ngun nhim khc l nc thi sinhot t nh v sinh, nh bp phc v cn b cng nhn vin. Nc thi nych yu cha cc cht gy nhim BOD, COD, SS, N, P, vi sinh vt mctrung bnh, nu nc thi ny khng c x l thch ng cng gy ra

nhng tc ng xu n mi trng.Trong sn xut bia cng ngh t thay i t nh my ny sang nh my khc,

s khc nhau c th ch l s p dng phng php ln men ni hay ln men chm. Nhng s khc nhau c bn l vn s dng nc cho qu trnh ra chai, mmc, nh xng iu dn n ti lng nc thi v hm lng cc chtnhim ca cc nh my bia rt khc nhau. cc nh my bia c bin php tunhon nc v cng ngh ra tit kim nc th lng nc thp, nh Cng HLin Bang c nc s dng v nc thi bia nh sau: [4]

- nh mc nc cp: 4 8 m3/1000lt bia, ti lng nc thi 2,5 6m3/1000 lit bia.

- Ti trng BOD5: 3 6 kg/1000 lt bia; t l BOD5/COD = 0,55 0,7.- Hm lng cc cht nhim trong nc thi nh sau:

BOD5 = 1100 n 1500 mg/l; COD = 1800 3000 mg/l;- Tng nit = 30 n 100 mg/l; tng photpho = 10 n 30 mg/l.

Vi cc bin php s dng nc hiu qu nht th nh mc nc thi ca nh

my bia khng th thp hn 2 3 m3

/1000 lt bia sn phm. Trung bnh lng ncthi nhiu nh my bia ln gp 10 n 20 ln lng bia sn phm. [4]Rosenwinker a ra kt qu phn tch c tnh nc thi ca mt s nh

my bia nh bng sau: Bng 1.6. c tnh nc thi ca mt s nh my bia[4]

Thng s n v Nh my I Nhmy II Nh my III pH - 5,7 11,7 - -BOD5 mg/l 1220 775 1622COD mg/l 1909 1220 2944SS mg/l 634 - - Nito tng mg/l 79,2 19,2 -Photpho tng mg/l 4,3 7,6 -Ti lng ncthi

m3/1000lt bia - 3,2 -

Ti trng nhim

kgBOD5/1000lt bia

- 3,5 -

Lu lng dng thi v c tnh dng thi trong cng ngh sn xut bia cn bin i theo chu k v ma sn xut [4].



14/100


Bng 1.7. c trng nc thi mt s c s sn xut bia trn a bn H Ni 2007 [5]

Tn c s

Nngsut

tr.l/nm

CODmg/l

BOD5mg/l

T-N T-PSS

mg/lpH

Snphm

1. Cngty bia H Ni

50 1305 948 15 4,5 226 7,15

Biahi,bialon, biachai

2. Cngty biang Nam

14 853 526 2,7 5,27 337 9,25Bia chai, bia lon

3.Cngty biaVit H

12 1374 1055 6 3 356 5,54 Bia hi

4. Nhmy biaCapital

2,5 1042 745 - - 199 7,03

5.Xng

bia visinh I

0,5 1004 873 - - 241 6,15

6. Cngty biaQung Ninh

11 1300 832 6,4 1,25 390 8,5

Bng 1.8. Thnh phn nc thi sn xut bia ca mt s Cng ty nm 2002[6]TT Ch tiu Nc thi trc x l1 pH 6-9,52 Hm lng cn l lng, mg/l 150-300



15/100


3 BOD5, mg/l 700-15004 COD, mg/l 850-19505 Tng Nit (TN) 15-456 Tng Phtpho (TP) 4,9-9,07 Coliform, MPN/100 ml


16/100


y l cng ngh ang c ng dng ph bin x l nc thi ngnh cng nghithc phm ni chung v ngnh bia ni ring cho hiu qu tt v n nh.

Hin nay, hu ht cc nh my bia u c h thng x l nc thi. Tuy nhinkhng phi nh my no cng x l nc ra t tiu chun. V vy, vn m

trng pht sinh t ngnh bia cn c quan tm v khc phc.I.2.2. Kh thi[1]

Bi Bi c th c to ra ti cng on tip nhn, vn chuyn v nghin ma

nghin go c bit l h thng nghin kh. Trong phn xng nghin, bi c tthu hi bng h thng ht v lc bi. Bi l thnh phn giu cht ha tan, tuy nhich yu l cc cht c th gy nh hng xu cho sn phm.

Kh thi ni hi Ch yu l kh thi pht sinh t qu trnh t nhin liu l du FO chy n

hi. Cc cht nhim trong kh thi ca l hi SO2, NOx, CO, VOX. Do vy, ccnh my cn xy dng h thng x l kh thi nhm m bo cht lng kh thtrc khi thi ra mi trng bn ngoi.

Kh CO2Kh CO2 sinh ra cng on ln men nhng kh ny thng c thu hi bng

h thng thu hi CO2 lm ngun cung cp gas cho bia thnh phm v bn lm

bnh cu ha.Tc nhn lnh

Hin nay, cc nh my ang s dng nhng loi tc nhn lnh nh NH3,Glycol, CFC. Tuy nhin, ngi ta xc nh c tc hi to ln ca CFC n mtrng, y l kh gy hiu ng nh knh v l tc nhn lm suy gim tng ozone vvy m hin nay CFC c thay th bng cc tc nhn lnh khc.

Kh thi t nh nuTrong qu trnh un si dch ng, thnh phn cc cht d bay hi trong dch

ng v hoa houblon bay hi thng to ra cc mi c trng cho khng gianxung quanh nh nu. gim lng kh to ra t nh nu, ngi ta c th s dcc h thng ngng t hi lp t trn cc ni nu v c nn li nh cc my nkh.

I.2.3. Cht thi rn I.2.3.1. Cht thi rn sinh hot Rc thi sinh hot sinh ra do cc hot ng sinh hot ca cn b cng nhn

vin trong Nh my bao gm 2 loi:- Loi cng: v hp, vt dng, bao b nha, thy tinh



17/100


- Loi mm: thc n tha, v tri cy, giy, nilonc tnh khong 0,3 kg/ngi.ngy [1], nh vy lng cht thi rn sinh hot s 250 ngi x 0,3 = 75 kg/ngy. Cc thnh phn ny c tp trung li mt cchring l, c bn hoc c loi b.

I.2.3.2. Cht thi rn cng nghip( Bng 1.9) Bng 1.9. Thnh phn v nh mc CTR ca cng nghip sn xut bia[1]

Loi cht thi Lng trung bnh (kg/hl bia)B malt v hoa houblon 18,86Men tha 2,64Cn nng 1,42Cn ngui 0,22Cn khong 0,62Bi malt 0,12 Nhn/ giy 0,29Cc cht bao gi 0,04

B malt v hoa houblon [1]C 100 kg malt nghin nh c th to ra 110 130 kg b malt i mch c

m 70 80% hay khong 20 kg/100 lt bia thnh phm. V vy c th c lnghng nm c khong 200 tn b malt m tng ng vi lng bia thnh phm l triu lt.

B malt vi nhiu thnh phn dinh dng nn thng c dng lm thc ngia sc. tng kh nng bo qun thnh phn sn phm ph ny v hn ch c ph cho vn chuyn, ngi ta c th sy b malt thnh dng kh.

Khc so vi b malt, b hoa houblon sau qu trnh un si thng c loi b, him khi ngi ta thu hi b hoa ti s dng vo bt k mc ch g. V thhu ht trong cc nh my bia, ngi ta thng nghin nh hoa hoc s dng cch phm hoa cao v hoa vin gim nhn cng cho cng on lc b hoa sau qutrnh un hoa. Sau un hoa, b hoa s c tch ra trong thit b lng xoy. Bao bcha cc ch phm hoa nh lon thic hoc giy thic c gom tp trung x l

Cn nngCn nng hnh thnh c tch ra thit b lng xoy, i khi c tch ra

cc thit b phn tch c bit hoc thng lng. Ni chung trong cn tch ra vcn cha mt phn dch ng cn c thu hi li. V th, nhiu nh my, ngta s dng dch cha cn ny lm nc ra b nhm tn thu lng cht chitrong dch ng ny, ng thi lm giu protein trong b malt. Tuy nhin, cng

on ny c th nh hng n cht lng ca dch ng v hn ch nh h



18/100


n cht lng ca bia, ngi ta thng khng tn dng lng dch ng cn trong b. [1]

Nm men thaMt s lng ln nm men ging sau khi s dng cn tha li, nu khn

c x l c th s dn ti s thi ra v gy nhim mi trng.Thng thng, t 1 triu lt bia mt nm c th to ra 15 18 tn b men cn

c x l [1]. Gii php tt nht l tn dng ngun dinh dng giu vitamin v protein ny lm thc n gia sc. B men phi c sy kh nhanh chng bqun, ng thi gim nhng tc ng ca chng i vi h vi sinh v h thng tiha ca gia sc. Mt hng khc c th c quan tm l s dng nm mentrong ngnh dc phm.

B cht tr lcT 100 lt bia sau lc thng to ra 500g bn tr lc. Nu tnh cho 1 triu lt

bia trong mt nm, s c 5 tn bn tr lc. [1]So vi cch x l x thng vo h thng nc thi nh nhiu nh my bia hi

nay vn ang s dng, bin php x l li bt tr lc i hi tn nhiu nhn cng chi ph. Trong , bt tr lc c th c gia nhit tr li v thay th cho 50%lng bt mi s dng lc bia.

Nhiu nh my bia ch x l bng cch bn tr lc thnh ng ln. Nc

trong bn s thot ra v hn ch s dn tri ca bn tr lc trn mt t. Cht tr ltrong cc b lng hoc trong cc ng ng lu ngy s bm cng v rt kh lo b.

Mt s gii php x l hin nay l p bn tr lc sao cho gim lng nxung di 50% bng my sy dng bng v my p lc. Sn phm kh sau qutrnh ny c th s dng lm phn bn nng nghip v c thnh phn nm men bmtheo.

Hin nay, ngi ta cng c th s dng bt tr lc thi dng trong cngnghip xy dng nh sn xut gch, xi mng.

Nhn mcVi h thng ra chai cng sut 1 triu lt bia trn nm, c th thi ra 1,5 tn

nhn chai [1]. S lng ny c th tng ln ph thuc loi nhn v s nhn s dntrn chai.

Nhn loi ra t my ra chai c tch ra v c p thu hi lng kimdnh trn nhn.



19/100


Vic loi b nhn i hi tn nhiu nng lng tun hon kim trong mra chai ng thi ch thu c bt nho giy kh thu hi v ti s dng. V thnhn ny ch yu c cht thnh ng.

Chai v

Lng chai v trong nh my ph thuc rt nhiu vo cht lng ca thtinh. C th gi nh rng vi thy tinh cht lng trung bnh, hng nm c khon3,5 tn vn thy tinh t cc bao b thu hi li c to ra tng ng vi cng sutriu lt. [1]

Nhng chai bia v c tp trung vo cc khu cha v c gi tr li nhmy thy tinh ti ch.

Lon biaLon bia rng, do v mng nn d b h hng. Ngi ta c lng c

khong 3 4% lon bia khng th s dng chit v b loi ra [1]. Cc lon c v gi li nh sn xut ti ch.

I.2.3.3. Cc cht thi th yu khc- Ba cng v ba cacton ng hp- Giy thi t phng qun l v sn xut- Kim loi v nha thi- G vn, lp xe c

- M v cht bo- Dung miCc thnh phn ny c tp trung li mt cch ring l, c bn hoc

loi b.Bn cnh , bn thi pht sinh trong qu trnh x l nc thi nh k cht v mang i chn lp bi Cng ty Mi trng th ca a phng hoccng c th lm ngun phn bn cho cy v thnh phn bn thi ch yu lcht hu c, khng c kim loi nng hay cc cht c hi.

I.2.4. Cc ngun nhim khc nhim nhit

Nhit mi trng lm vic nh my bia c th chia lm 2 loi nh hnti sc khe con ngi v mi trng nh sau:

- Vng nhit thp: Trong phn xng ln men, khong 6 80C- Vng nhit cao: Trong khu vc l hi, phn xng nu Do vy, cn

b tr h thng thng gi tt thot nhit.

nhim ting n Nhn chung, ting n to ra cc v tr sau:



20/100


- Trong phn xng nghin- Trong phn xng ng chai- Gn my nn cht lm lnh v khng kh- Gn thit b ngng t hi

- Gn my nn hi gim ting n pht ra, c th s dng cc bin php sau:- La chn vt liu xy dng: tng i cch m, ca s kn- Lp t thit b gim m phn xng chit chai- Hn ch s dng tng ghp- Lm v cch m nhng my gy n ln.Cng nghip sn xut Bia l mt trong nhng ngnh cng nghip ng vai tr

quan trng trong nn kinh t c nc. Ngoi vic gii quyt vic lm cho hng vlao ng, cn ng gp mt phn khng nh cho ngn sch Nh nc. Tuy nhin, bn cnh nhng li ch to ln , vn cht thi cn phi c quan tm, c bl nc thi.

Cng nghip sn xut Bia l mt trong nhng ngnh sn xut s dng lnnc kh ln. Do , lng nc thi pht sinh trong qu trnh sn xut cn phc x l mt cch hiu qu.

I.3. GII THIU CNG TY C PHN BIA SI GN MIN TRUNGI.3.1. Gii thiu s lc v Cng ty bia Si Gn Min Trung1. Tn cng ty v v tr a l

Tn Cng ty : CNG TY C PHN BIA SI GN MINTRUNG - BNH NH

Tr s giao dch : KCN Ph Ti TP Quy Nhn - tnh Bnh nhin thoi : 056.3841.392 hoc 056.3841.369Fax : 056.3841.520

Email : [email protected] : www.sqb.com.vn Ngi i din theo php lut ca Cng ty:Chc danh : Tng Gim cH v tn : ng Nguyn Ngc Trim.

Cng ty Bia Si Gn Min Trung- Bnh nh nm khu cng nghip Ph Ti TP Quy Nhn - tnh Bnh nh (thuc khu vc 5, phng Trn Quang Diu, TPQuy Nhn, Bnh nh). V tr ca Nh my rt thun li v giao thng, vn chuyhng ha trong qu trnh sn xut, ng thi cng thun tin trong vic chuyn chsn phm i tiu th cc tnh Min Trung v Ty Nguyn.Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355120
mailto:[email protected]://www.sqb.com.vn/mailto:[email protected]://www.sqb.com.vn/


21/100


Cc hng tip gip ca Cng ty:- Hng ng : gip ng Trung Tm KCN- Hng Ty : gip ng ni b KCN

- Hng Nam : gip Cng ty giy da An Ph- Hng Bc : gip khu t trng v nh dn.

2. Hin trng sn xut v k hoch pht trin ca Cng tyTin thn ca Cng ty c phn bia Si Gn Min Trung l Cng ty bia Qui

Nhn. Cng ty bia Qui Nhn c khi cng xy dng vo thng 9 nm 1995 theoquyt nh 5146/QUB ngy 25 thng 7 nm 1994 ca y ban nhn dn tnh Bnhnh, vi cng sut thit k ban u 5 triu lt bia/nm.

Thng 10 nm 1998 Cng ty tin hnh nng cng sut ln 10 triu lt bia/nmv i vo hot ng thng 3 nm 1999.

Thng 2 nm 2001 Cng ty nng cng sut ln 20 triu lt bia/nm. Nm 2005,cng sut cc i ca Cng ty l 50 triu lt bia/nm v i tn thnh Cng ty c phn bia Si Gn Min Trung vo nm 2008.

Hin nay, iu kin kinh doanh sn xut ca Cng ty ang trn pht trin vc d nh nng cng sut ln 100 triu lt bia/nm trong tng lai.

Cc loi sn phm v th trng tiu th

Hin nay sn phm ca Cng ty bao gm:- Bia chai Qui Nhn dung tch 330ml v 450ml.- Bia chai Si Gn dung tch 355ml (sn phm ch yu ca nh my).- Bia chai Lowen dung tch 355ml.- Bia hi.

Bia Si Gn hin nay ang l sn phm ch yu ca Cng ty. N c tiu th cc huyn trong tnh v cc tnh ln cn nh: Ph Yn, Qung Ngi, Gia Lai,KonTum, klk.

Bia Lowen l sn phm cao cp ca Cng ty do sn xut vi s lng hch, th trng tiu th cng hn ch.

I.3.2. Hin trng x l nc thi ti Cng tyHin ti Cng ty ang vn hnh trm x l nc thi c xy dng trn

khun t nm pha ng ca nh my, theo tng th mt bng qui hoch chungCao trnh hon thin ti v tr xy dng h thng x l nc thi rt thp so vi catrnh khu vc sn xut ca nh my. Ti v tr xy dng ny, ton b nc thi cnh my theo tuyn ng D400 t chy v khu x l.

Lu lng thit k ca trm x l nc thi:- Lu lng nc thi thit k: Q = 1200 m3/ngy m,



22/100


- Lu lng trung bnh: Qtb = 50 m3/h,- Lu lng cc i: Qmax = 100 m3/h.

Yu cu ca nc thi sau x l:- Nc thi sau x l t tiu chun ct A theo TCVN 5945 2005.

- Nc thi sau x l theo ng cng thot nc chung ca khu cngnghip thi ra sng H Thanh.

Cng ngh x l nc thi c la chn l cng ngh x l sinh hc ym k(UASB) kt hp vi x l sinh hc hiu kh dng m (SBR).

Do h thng x l nc thi c u t tt, cng ngh x l ph hp vi trng dng thi; ng thi c vn hnh, theo di thng xuyn cht lng nu ra bi cc k s chuyn ngnh mi trng nn hin ti trm x l nc thi ccng ty ang vn hnh tt, p ng yu cu nc u ra theo tiu chun.

I.3.3. S cn thit phi xy dng h thng x l nc thi mi Nh trnh by phn trn, hin ti h thng x l nc thi ca cng t

ang vn hnh tt, cht lng nc u ra m bo theo tiu chun thi nhng thng ny ang xy dng vi lu lng nc thi trung bnh 1200 m3/ngy m(cc i 2400 m3/ngy m). Khi nng cng sut ca nh my ln 100 triu lt bia/nm, lng nc thi cc i theo c tnh s b l 4000 m3/ngy m. Khi ,h thng x l nc thi hin ti s khng p ng c yu cu. V th cn th

phi xy dng h thng x l nc thi mi vi lu lng thit k v c trdng thi mi t hiu qu x l tt.Cng ngh x l, tnh ton thit k h thng x l nc thi mi ny

trnh by c th cc chng sau trong n.



23/100


CHNG IIC S L THUYT CC PHNG PHP X L SINH HC

NC THI.

Do c tnh nc thi ca cng ngh sn xut bia c cha hm lng cc chhu c cao trng thi ha tan v trng thi l lng, trong ch yu lhidratcacbon, protein v cc axit hu c, l cc cht c kh nng phn hy sinh hcT l gia BOD5 v COD nm trong khong t 0,5 0,7 nn chng thch hp vi phng php x l sinh hc.

Nc thi trc khi a vo x l sinh hc cn qua cc phng php x l chc, ha hc, ha l loi b cc tp cht th, cc thnh phn gy bt li ch phng php x l sinh hc. C th tng phng php c trnh by di y.II.1. Cc phng php h tr cho phng php x l sinh hc nc thi

II.1.1. Phng php c hc[7]Phng php x l c hc thng l giai on u tin trong dy chuyn cng

ngh x l nc thi (giai on tin x l), c nhim v loi ra khi nc thi c cc vt c th gy tc nghn ng ng, lm h hi my bm v lm gim hiqu x l cho cc giai on sau, c th:

- Loi b hoc ct nh nhng vt ni l lng c kch thc ln

trong nc thi nh mnh g, nha, gc bng, gi rch, v hoa qu- Loi b cn nng nh ct, si, mnh thy tinh, mnh kim loi- Loi b phn ln du m.Cc cng trnh b tr trong giai on tin x l gm song chn rc, li chn

rc, thit b nghin, ct vn rc (nu cn), b lng ct, b iu ha, tch du m, lc hc

Nc thi cng nghip sn xut bia c cha mnh thy tinh v (chai v), nhngiy, nt chai, hm lng cht l lng cao (400 800 mg/l) nn cn phi qua

giai on x l c hc trc khi sang cc giai on x l tip theo.II.1.2. Phng php ha hc ha l[8]

C s ca phng php ha hc l cc phn ng ha hc, cc qu trnh ha ldin ra gia cht bn vi ha cht cho thm vo.

Cc phng php ha hc nh oxi ha, trung ha, trao i ion, ng keo t,kh trng; cn cc phng php ha l nh tuyn ni, hp ph

+ Phng php trung ho, iu chnh pH Nc thi thng c nhng gi tr pH khc nhau. Mun nc thi c x l

tt bng phng php sinh hc phi tin hnh trung ha v iu chnh pH v vn6,5 7,5.Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355123


24/100


Trung ho c th thc hin bng trn dng thi c tnh axit vi dng thi ctnh kim hoc s dng cc ho cht nh: H2SO4, NaOH, NaHCO3, Na2CO3, CaO,Ca(OH)2, MgO, CaCO3 iu chnh pH thng kt hp b iu ho hay b keot.

c trng chung nc thi ngnh bia c gi tr pH kim tnh do dng thi caqu trnh ra chai c pH cao. Mt khc, nc v sinh cc thit b trong nhxng cng cha axit nn c s dao ng pH qua tng cng on. V vy, cn phiu chnh pH v gi tr thch hp cho x l sinh hc pha sau; cng on ny thc hin kt hp trong b iu ha.

+ Keo tKeo t l mt hin tng lm mt s n nh ca cc ht huyn ph dng ke

cui cng to ra cc cm ht khi c s tip xc gia cc ht. Ngi ta s dng cc loi phn nhm, phn st hoc hn hp hai loi phn ny

lm cht keo t.Hin nay, thng thng ngi ta cho thm cc cht tr keo nh polymer hu

c tng cng qu trnh to bng v lng nh polyacrylamit. N tan trong nv c tc dng nh nhng cu ni kt hp cc ht phn tn nh thnh tp hp hln c kh nng lng tt hn. V vy, vic b sung thm cht tr keo t s gigim liu lng cc cht keo t, gim thi gian keo t v nng cao tc lng c

bng keo.i vi nc thi ngnh bia th phng php ny khng thch hp v trongnc thi bia, hm lng cc cht hu c trng thi ha tan v trng thi l lncao m cc cht ny khng thch hp cho phng php keo t.

+ Hp phHp ph c ngha l s chuyn dch mt phn t t pha lng n pha rn

Phng php ny c dng loi b cc cht bn ha tan trong nc m ph php x l sinh hc cng cc phng php khc khng loi b c vi hm ln

rt nh. Thng thng y l cc hp cht ha tan c c tnh cao hoc cc cht cmi, v v mu rt kh chu.

Cc cht hp ph thng dng l than hot tnh, t st hot tnh, silicagenkeo nhm Trong than hot tnh c s dng ph bin nht.

Cc cht nhim trong nc thi bia l nhng cht c kh nng phn hy sinhhc. Hiu qu kh cc cht ny bng phng php sinh hc tng i d nn khcn s dng phng php hp ph.

+ Tuyn ni



25/100


Phng php ny da trn nguyn tc: cc phn t phn tn trong nc c khnng t lng km, nhng c kh nng kt dnh vo cc bt kh ni ln trn b mSau ngi ta tch cc bt kh cng cc phn t dnh ra khi nc.

Phng php tuyn ni c dng rng ri trong luyn kim, thu hi khong

sn qu v cng c dng trong x l nc thi tch cc ht keo l lng, tcdu m... Tuy nhin, i vi nc thi ngnh bia, do hm lng cc cht l lnkhng cao lm v kh nng t lng tng i tt nn phng php tuyn ni hnh khng c p dng.

+Trao i ionTrao i ion l mt qu trnh trong cc ion trn b mt ca cht rn trao

vi cc ion c cng in tch trong dung dch khi tip xc vi nhau. Cc cht nygi l cc ionit v chng hon ton tan trong nc.

Phng php ny c dng loi cc ion kim loi cng nh cc cht chaasen, xianua, cht phng x ra khi nc; ng thi n cn c dng ph bin lm mm nc, loi ion Ca2+, Mg2+ ra khi nc cng.

i vi nc thi bia th phng php ny hu nh khng c s dng.+ Kh trng

Dng cc cht c tnh c i vi vi sinh vt, to, ng vt nguyn sinh, giunsn... lm sch nc, m bo tiu chun v sinh vo ngun tip nhn hoc

s dng. Kh trng c th dng cc ha cht hoc tc nhn vt l nh ozon, tia tngoi.Cc cht kh trng thng dng nht l kh hoc nc clo, nc Javen, v

clorua, cc hypoclorit, cloramin B...Trong qu trnh x l nc thi, cng on kh trng thng c t cu

qu trnh. i vi nc thi ngnh bia, sau khi qua cc phng php x l c hcha hc, ha l v sinh hc th hm lng cc vi sinh vt gy bnh gim ng knhng m bo tiu chun v sinh vo ngun hoc ti s dng th cn ph

qua bc kh trng cui cng.II.2. Gii thiu cc phng php x l sinh hc nc thi

Phng php sinh hc l s dng cc vi sinh vt phn gii cc cht nhimhu c c trong nc thi. Vi sinh vt s dng cc cht hu c v mt s khoncht lm ngun dinh dng xy dng t bo, ng thi tng hp nng lng chqu trnh sng. Nh hot ng sng ca vi sinh vt, cc cht nhim c chuyho v nc thi c lm sch.

Qu trnh x l sinh hc nc thi c th chia lm hai qu trnh l phn huym kh v phn hu hiu kh; c th x l trong iu kin t nhin hay trong ikin nhn to.Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355125


26/100


II.2.1. Phng php x l sinh hc nc thi trong iu kin t nhin[8]C s ca phng php x l nc thi trong iu kin t nhin l da v

hot ng sng ca h vi sinh vt c trong t, nc mt chuyn ho cc hcht nhim.

X l nc thi trong h sinh hcThc cht ca qu trnh x l ny l s dng khu h vi sinh vt (vi khun, to

nguyn sinh vt) t nhin c trong nc mt lm sch nc.H sinh hc l dng x l trong iu kin t nhin c p dng rng ri h

c v c nhng u im nh: to dng nc ti tiu v iu ha dng thi, iho vi kh hu trong khu vc, khng yu cu vn u t, bo tr, vn hnh v qul n gin, hiu qu x l cao. Tuy nhin, nhc im ca h sinh hc l yu cdin tch ln v kh iu khin c qu trnh x l, nc h thng c mi khchu i vi khu vc xung quanh.

Theo nguyn tc hot ng ca h v c ch phn gii cc cht nhim mngi ta chia ra lm 3 loi h:

a. X l nc thi bng h hiu kh:H hiu kh lm sch nc bng qu trnh oxi ho nh cc vi sinh vt hiu kh

v h hp tu tin c trong nc. Nhu cu oxi cho qu trnh oxi ho c p ng nh khuch tn b mt ho

lm thong nhn to. h lm thong t nhin, oxi khng kh d dng khuch tnvo lp nc pha trn v nh sng mt tri chiu ri, lm cho to pht trin tihnh quang hp thi ra oxi. m bo nh sng qua nc, chiu su ca lp n phi nh, thng l 30 40cm, do chiu su nh nn thng th din tch ln. Thgian lu nc t 3 12 ngy. h lm thong nhn to ngun cung cp oxi cho vsinh vt hiu kh l cc thit b khuy trn c hc hoc nn kh. Nh vy, mc hiu kh trong h thng mnh hn, u hn v su ca h cng ln hn (2 4,5m). Thi gian lu nc trong h khong 1 3 ngy.

b. X l nc thi bng h k kh Dng lng v phn hy cn bng phng php sinh ha t nhin da trn

c s sng v hot ng ca loi vi sinh vt k kh.Loi h ny dng x l nc thi cng nghip c nhim bn cao. Tron

qu trnh x l sinh mi thi kh chu nn cn t cch xa nh my. duy tr iukin k kh th chiu su h phi ln, thng ly bng 2,4 3,6m.

c. X l nc thi bng h ty nghiH sinh hc ty tin su t 1,5 2m. Ngoi tng hiu kh pha trn h cn c

cc tng k kh ty tin, k kh lp bn cn lng pha di. Thi gian lu ntrong h t 3 5 ngy.Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355126


27/100


Oxi cung cp cho qu trnh chuyn ha cht hu c trong h ch yu l doquang hp ca to v khuch tn t khng kh qua b mt h. Ngoi ra cc vi khuty tin hoc vi khun k kh cn s dng oxi lin kt t nitrit, nitrat, sunphat oxi ha cht hu c.

Cc phng php x l sinh hc nc thi trong iu kin t nhin nhnchung kh thc hin c l v:

- Din tch xy dng qu ln,- nhim mi trng xung quanh,- Ma ma s kh x l v nc thi chy trn ra sng,- Vi sinh vt gy bnh cao,- Tui th cng trnh thp.

II.2.2. Phng php x l sinh hc nc thi trong iu kin nhn to II.2.2.1. C s l thuyt qu trnh x l sinh hc ym kh [7, 8, 9, 10, 11]X l sinh hc ym kh l mt trong nhng qu trnh c s dng x l

bn v nc thi c hm lng cht hu c cao (BOD > 1800mg/l, SS = 300-400mg/l), sn phm cui cng l CH4, CO2.

Nguyn l ca phng phpX l sinh hc bng vi sinh ym kh l qu trnh phn hu cc cht hu c, v

c c trong nc thi khi khng c oxi. Phng php ny dng n nh cn v

x l nc thi cng nghip c nng COD, BOD cao. Qu trnh phn hy cccht thc hin nh cc chng vi khun k kh bt buc v k kh khng bt buc.C ch ca qu trnh x l ym kh

C ch phn gii ym kh:Cht nhim CH4+CO2+H2S+E

Qu trnh phn hy cc cht hu c l qu trnh phc tp trong mi trngkhng c khng kh, gm nhiu giai on v sn phm cui cng l CH4, CO2, H2S, NH3

Giai on 1: Giai on thy phnCc hp cht hu c phn t lng ln nh protein, gluxit, lipit... b phn

hy di tc dng ca cc Enzym hydrolazaca vi sinh vt thnh cc cht hu c phn t lng nh nh ng n, axit amin, axit hu c, peptit, glyxerin...

Trong giai on ny, cc hp cht gluxit phn t lng nh, cc hp chthu c cha Nit (protein) phn hy nhanh hn, trong khi cc hp cht hu c c

phn t lng ln nh tinh bt, cc axit bo c phn hy chm, c bit lcellulose v lignocellulose chuyn ha rt chm v khng trit do cu trc ph


Chuyn ha ym kh

27


28/100


tp. Cc vi sinh vt tham gia vo qu trnh thy phn ph thuc vo cc cht nhim u vo v cc c trng khc ca nc thi.

Giai on 2: Giai on ln men axit hu c Cc sn phm thy phn s c cc vi sinh vt hp th v chuyn ha tron

iu kin ym kh. Sn phm phn gii l cc axit hu c phn t lng nh nhaxit propionic, axit butyric, axit lactic..., cc cht trung tnh nh ru, andehyt,axeton. Ngoi ra, mt s kh cng c to thnh nh CO2, H2, H2S, mt lng nhCH4...

Thnh phn ca cc sn phm trong giai on ln men ph thuc vo bncht cc cht nhim, tc nhn sinh hc v iu kin mi trng.

c bit trong giai on ny, nit c chuyn thnh NH4+ mt phn nhc s dng xy dng t bo, phn cn li tn ti trong nc thi di d NH4+.

Giai on 3: Giai on ln men axit axeticCc sn phm ln men phn t lng ln nhaxit bo, axit lactic... s c

tng bc chuyn ha thnh axit axetic.- Chuyn ha axit lactic:3CH3-CHOH-COOH2CH3-CH2-COOH + CH3-COOH + CO2 + 2H2O- Oxy ha lin kt ca cc axit bo bng c ch oxy ha-kh:

R CH3CH2COOH + 2H2O R n-2 COOH + CH3COOHAxit bo mch di Axit bo mch ngn Axit axeticGiai on 4: Giai on Mtan ha

Mtan ha l giai on quan trng nht ca ton b qu trnh x l ym kh.Di tc dng ca ccvi khun mtan ha, cc axit hu c, cc cht trung tnh... b phn gii to thnh kh metan.

- Khong 30% kh CH4 to thnh do qu trnh kh CO2:+ Kh CO2 bng H2:

CO2 + 4H2 VK CH4 + 2H2O+ Kh CO2 bng oxy ha kh:

- Khong 70% kh mtan cn li c to thnh nh cc qu trnhDecacboxyl ha cc axit hu c v cc cht trung tnh.

+ CH4 c to thnh do Decacboxyl ha axit axetic:CH3COOHCH4 + CO2


4NADH2 4NAD

CO2 CH4 + 2H2O

28


29/100


+ CH4 c hnh thnh do Decacboxyl ha cc axit hu c khc:4CH3-CH2-COOH + 2H2O 7CH4 + 5CO22CH3-(CH2)2-COOH + 2H2O5CH4 + 3CO2

+ CH4 cng c th c hnh thnh do Decacboxyl cc cht trung tnh:

2C2H5OH 3CH4 + CO2 CH3-CO-CH3 + H2O 2CH4 + CO2Tc nhn sinh hc

Trong phn gii ym kh, cc qu trnh thy phn v ln men xy ra di tcdng ca nhiu chng vi khun khc nhau. Thnh phn h vi sinh vt trong phgii ym kh ph thuc ch yu vo bn cht ca cc cht nhim c trong nthi.

- Vi sinh vt trong giai on thy phn v ln men axit hu c:+ Mi trng giu xenlulo thng c cc vi khun: Bacillus, Pseudomonas, Alcaligenes.+ Mi trng giu protein: Bacillus, Clostridium, Proteus v E.Coli+ Mi trng giu lipit: Bacillus, Pseudomonas, Alcaligenes, Bacterioides.+ Mi trng giu tinh bt:Micrococus, Lactobacillus, Pseudomonas,Clostridium.

Trong cc chng: Lactobacillus, Pseudomonas, Bacillus, Clostridium, Bacterioideschim a s.

Phn ln cc vi khun thy phn v ln men axit hu c t nhy cm vimi trng. Chng c th pht trin trong di pH rng t 2 7. Tuy nhin, pHopt = 5 7 nhit 33 400C.

- Vi khun axetogene:Vi khun to axit axetic thng pht trin trong mi trng cng vi

metan. Vi khun Axetogene to H2 trong qu trnh ln men nhng li b chnh sn phm ny c ch. V vy, trong mi trng c cc vi khun metan s dng H2 hocH+ kh CO2.

Mt s chng vi khun Axetogene c hiu qu metan ha cao nh:+ Syntrophobacter woloni, Syn. Wolfei, Syn. Buswweni.

Nhit ti u l 33 400C, pH = 6 8.Hai nhm vi khun khc cng c kh nng to axit axetic nh:

+ Nhm vi khun kh sunphat:Selenomonosas, Clostridiumv Dasolfovibrio. Trong mi trng hn hp vi vi khun metan ha toaxit axetic.



30/100


+ Nhm vi khun Homoacetogen, to axit axetic t CO2 v H2.2CO2 + 4H2 CH3-COOH + 2H2O

Nhm ny c ngha c bit v chng cnh tranh H2 vi vi khunmetan.

- Vi khun metan ha: thuc 2 nhm chnh+ Nhm a m (Mesophyl, ln men to CH4 35 370C, pH=6,8 7,5):gmMethanobacterium(trc khun) , Methanococcus(n cu khun),Methanosaccina(bt cu khun).+ Nhm a nng (Thermophyl, ln men to CH4 55 600C):gmMethanobacillus, Methanospirillium, Methanothrix.

Vi khun ln men metan l nhng vi khun ym kh nghim ngt. Chng rtmn cm vi s c mt ca O2. Do , thit b ln men phi kn, pHopt = 6,8 7,5.

Cc yu t nh hng n qu trnh x l sinh hc ym kh - Nhit

y l yu t iu tit cng ca qu trnh bi v n nh hng ti hong chuyn ha ca vi sinh vt. Nhit ti u cho ton qu trnh ph thuc vchng loi vi sinh vt. Trong thc t, c 2 nhm a nng v a m u c kh nn phn hy ym kh.

Di nhit cho qu trnh phn gii ym kh rng t 30 600C. Tuy nhin,

nhit ti u cho mi qu trnh cn ph thuc vo c tnh a nhit ca tc nhsinh hc. Bi ch mt khong bin ng nhit nh cng nh hng ti hot lca vi sinh vt.

Vi cc vi sinh vt a nng, khong nhit ti u ca chng t 55 600C,cn vi cc vi sinh vt a m th 33 370C.

thu c hiu sut to kh metan cao v n nh th phi n nh nhit trong di a m.

- pH

Thit b phn hy ym kh c vn hnh trong khong pH t 6,6 7,6 vkhong ti u t 7 7,2. Mc d vy, vi sinh vt axit ha c th chu c pH = 5nhng gi tr ny vi khun metan ha b c ch mnh.

Thit b phn hy ym kh cn c trang b thit b o v iu chnh pH khcn thit m bo n nh pH ca h thng gi tr trung tnh. Nu pH xuthp cn b sung kim hoc ngng cp liu thit b t iu chnh.

- Nng c cht Vi khun thc hin qu trnh phn gii ym kh c tc to sinh khi rt nh

Thc nghim cho thy t l C/N cn duy tr 30/1. Cc yu t quan trng khc nhP, Ca, K, Na cng cn b sung ty theo thnh phn v tnh cht nc thi cn x lVin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355130


31/100


- Ti trng khi(Tk , kgCOD/m3/ngy)Ti trng cht hu c ph thuc vo ti lng c trong nc thi, ti trn

thy lc hay thi gian lu. Khi ti lng cht hu c cao s lm d tha cc axhu c dn n pH gim, gy bt li cho vi khun metan ha. Ti lng cht hu

thp s khng c li cho qu trnh kh ha.Thi gian lu nc ph thuc vo c tnh ca nc thi v iu kin m

trng. Thi gian lu qu ngn (ti trng khi cao) s khng cho php cc vi khuym kh, c bit l vi khun metan tip xc v trao i vi cc cht nhim nlm gim hiu qu x l; ngc li thi gian lu cng lu cng c li cho hiu quto biogas v x l nc thi nhng gy chi ph tn km. Thi gian ti u cho qutrnh phn hy ym kh trong h thng UASB l 0,5 6 ngy.

- Th oxy ha kh (hm lng H 2 ) trong giai on to axit axeticLactat + H2O axetat + 2H2 + CO2 + QEtanol + H2O axetat + 2H2 - QButyrat + H2O axetat + 2H2 - QPropionat + H2O axetat + 3H2 + CO2 - Q

Cc phn ng oxy ha kh ny s c thc hin khi khng c cc vi khunc kh nng s dng H2.

Th oxy ha kh nh hng ti qu trnh phn gii ym kh theo nguyn l

Le Chaterier v chuyn dch cn bng ha hc:Mi s thay i ca cc yu t xcnh trng thi ca mt h cn bng s lm cho cn bng chuyn dch v phachng li nhng thay i .Kh H2 sinh ra t cc phn ng trn nu khng cgii phng s gy ra p lc ln (nng cao), lm cho cn bng chuyn dch v pha khng sinh ra H2 na v hiu qu ln men axit axetic gim xung.

Nh c qu trnh metan ha lm gim nng axetat, hn na H2 c cc vikhun metan ha s dng kh CO2 to kh CH4 nn nng kh H2 gim, cn bng s chuyn dich theo hng to ra sn phm axetat v H2. Nu qu trnh ny

din ra lin tc th hiu qu x l nc thi rt cao.- Cc cht c

Cc cht c ch hoc c i vi cc vi sinh vt phn gii ym kh kh adng:

+ Amon: c ch qu trnh metan ha.+ Hydrocacbua halogen ha: c ch qu trnh metan ha.+ Hydrocacbua vng thm: nh hng ln ti nhm vi khun metanha.+ Mt s kim loi nng.



32/100


c im thit b UASBCc dng thit b x l ym kh rt a dng v phong ph. T loi n gin

nh hm Biogas n phc tp nh thit bUASB.Cc dng x l ym kh nh: thit b ym kh tip xc, thit b ym kh gi lng, thit b x l chy ngc qua lp bhot tnh dng hng ln (UASB), thit b dng thp m...

Trong , UASB l dng x l c s dng rng ri trong x l nhiu lonc thi c nng nhim cht hu c cao; n rt ph hp cho x l nc th bia. Cu to B UASB c th hin trnhnh v 3.1.

- Cu toB UASB (Upflow Anaerobic Sludge Blanket ) c th lm bng b tng ct

thp hoc bng gch, thng c mt bng hnh ch nht, c cch nhit vi bngoi. tch kh ra khi nc thi, trong b g thm tm phng t nghing so v phng ngang gc 35o.

Hnh 2.1. S cu to b UASB[7].

1. Vng phn ng k kh; 2. Vng lng cn; 3. Ca dn hn hp bn ncsau khi tch kh i vo ngn lng; 4.Ca tun hon cn; 5.Mng thu nc; 6.

Nc sang Aeroten; 7. Kh sn phm thu c; 8. ng dn hn hp kh. - Nguyn tc hot ng

Nc thi sau khi iu chnh pH theo ng dn vo h thng phn phi u trdin tch y b. Nc thi t di ln vi vn tc 0,6 0,9 m/s gi cho lp b

lun trng thi l lng. Hn hp bn k kh trong b hp th cht hu c ha tatrong nc thi, phn hy v chuyn ha chng thnh kh (70 80% mtan, 20



33/100


30% ccbonic) v nc. Cc ht bn cn bm vo cc bt kh c sinh ra ni lntrn b mt lm xo trn v gy ra dng tun hon cc b trong lp cn l lng. Khht cn ni ln va phi tm chn pha trn b v ra, kh thot ln trn cn ri xundi. Hn hp bn nc tch ht kh c chuyn vo ngn lng. Ht cn tro

ngn lng tch bn lng xung y v tun hon li vng phn ng k kh. Ntrong c thu vo mng v c dn sang b x l t II (Aeroten). Kh biogasc thu v bnh cha ri theo ng dn ra ngoi.

Bn trong b c hnh thnh hai vng r rt: chiu cao khong 1/4 tnh ty ln, lp bn hnh thnh do cc ht cn keo t c nng t 5000 7000 mg/l pha trn lp ny l lp bn l lng c nng 1000 3000 mg/l gm cc bng cnchuyn ng gia lp bn y v bn tun hon t ngn lng ri xung. Bn tron b l sinh khi ng vai tr quyt nh trong vic phn hy v chuyn ha cht hc. Nng cao ca bn hot tnh trong b cho php b lm vic vi ti trng chhu c cao.

hnh thnh khi bn hot tnh nng , lm vic hiu qu i hi thgian vn hnh khi ng t 3 4 thng. Nu cy vi khun to axit v vi khun tmtan trc vi nng thch hp v vn hnh vi ch thy lc nh hn 1cng sut thit k, thi gian khi ng c th rt xung cn 2 3 tun.

Lng cn d bng 0,15 0,2% lng COD, tc bng mt na cn sinh ra s

vi x l hiu kh. Cn d nh k x ra bn ngoi v c th tip tc a i lm kh- u, nhc im ca UASB+ u im:

- Nng lng cn thit cho h thng UASB rt thp.- Lng bn to thnh nh (nh hn 3 20 ln x l hiu kh).- C th tun hon hay khng tun hon li bn.- To sn phm kh sinh hc CH4 (70 80%), l ngun nng lng

sch, c th s dng cho sinh hot.

- UASB rt thch hp cho x l nc thi c nhiu cn l lng.- UASB c th phn hy cc cht hu c phc tp: vng, halogen- UASB thch hp cho x l nc thi cng nghip c hm lng v

ti lng nhim cao.+ Nhc im:

- Cc qu trnh xy ra trong thit b phc tp.- Tc nhn sinh hc rt nhy cm vi cc yu t mi trng.- Qu trnh khi ng ko di.- Yu cu cao s tng thch gia thc n v hm lng sinh khi.- Qu trnh c nh vi khun trn lp m rt kh iu khin.



34/100


Qu trnh x l ym kh to ra lng bn t v chi ph nng lng thp. Nhcim ca x l ym kh l thi gian lu nc thi ln, thi gian n nh cng nghdi (3 6 thng). Qui trnh vn hnh tng i phc tp, hiu qu x l ph thunhiu vo cc yu t mi trng, bin ng ln t 60 90%.

II.2.2.2. C s l thuyt ca qu trnh x l sinh hc hiu kh [8, 10, 11] Nguyn l ca qu trnh x l nc thi bng bn hot tnh

S dng cc vi sinh vt oxy ho cc cht hu c v v c c kh nngchuyn ho sinh hc c; ng thi chnh vi sinh vt cng s dng mt phn chhu c v nng lng khai thc c t qu trnh oxi ho tng hp nn sinh khca chng.

C ch ca qu trnh x l hiu kh + Oxy ho cc hp cht hu c khng cha nit (Gluxit, hyrocacbua,

pectin, axit hu c, cc cht hu c phn t lng nh khc)

C x H yO z + ( 4 2 y z x+ )O2 v s v xCO2 + 2

y H 2O + E

+ Oxy ho cc hp cht hu c c cha Nit (Protein, Peptit, axitamin)

C x H yO z N + ( 4 2 y z x+ + 34 )O2

v s v xCO2 +

32

y H 2O + NH 3 + E

+ Qu trnh oxy ho cc hp cht hu c tng hp sinh khi:

C x H yO z + NH 3 + ( 4 2 y z

x+ - 5)O2 v s v

C 5 H 7 NO2 +(x 5)CO2+4

2 y

H 2O +E +Qu trnh t hy ca sinh khi:

C 5 H 7 NO2 + 5O2 5CO2 + 2 H 2O + NH 3 + E Ngoi ra trong h thng cn xy ra cc qu trnh nitrit v nitrat ho:

+ Nitrit ho : NH4+ + 3/2 O2 + H2O v s v NO2- + 2 H3O+ + E.+ Nitrat ho: NO2- + O2 v s v NO3-

Phng trnh tng qut : NH4+ +2O2+ H2O v s v NO3- + 2H3O+

+ Oxy ho cc hp cht v c:24S SO ; 34 P PO

Fe2+ Fe3+ (S chuyn ho thnh Fe3+ gip cho ezim ti tothng xuyn)

Tc nhn sinh hc Tc nhn sinh hc c s dng trong qu trnh x l hiu kh c th l vi

sinh vt h hp hiu kh hay tu tin, nhng phi m bo cc yu cu sau:- Chuyn ho nhanh cc hp cht hu c.- C kch thc tng i ln bng sinh hc lng nhanh ( =50 200

m).Vin Khoa hc v Cng ngh Mi trng (INEST) HBKHN Tel 04.38681686 Fax 04.3869355134


35/100


- C kh nng to nha bo.- Khng to ra cc kh gy nhim mi trng nh: H2S, Indol, Scatol...

Da trn cc yu cu th cc vi khun h hp hiu kh c s dng chyu; ngoi ra cn c vi khun h hp ty tin v nguyn sinh ng vt.

Vi khun h hp hiu kh:+ Pseudomonas+ Aerobacter aerogenes+ Bacillus Subtilis(pht trin trong mi trng giu protein)+ Flavobacterium(pht trin trong mi trng giu st)+ Nitrosomonas vinogradski(vi khun nitrit ho).

Vi khun h hp tu tin:+ Cellulosomonas bizotera(c kh nng oxy ho xenlluloza)+ Rhodospeudomonas(c mu hng)+ Nitrobacter (c kh nng nitrat ho)+ Microthrix(vi khun dng si c mu trng)+ Thiothrix(vi khun dng si c mu trng)

Nguyn sinh ng vt: Bao gm 2 dng ch yu:+ Trng t (Cillatae)+ Trng roi(Flagellate)

Do c kch thc ln khong 30 50m nn trong b x l n c vai tr nhsau:

+ Bm vo bn lm cho bn d lng hn+ n cn l lng gp phn lm trong nc+ L ch th nh gi mc cp kh cho b+ L ch th nh gi cc cht c c trong nc thi.Cc yu t nh hng n qu trnh x l sinh hc hiu kh [8]- Oxi ha tan (DO)

y l thng s quan trng i vi h thng x l hiu kh. DO c cp lintc p ng yu cu oxy ha ca vi sinh vt.

Nu thiu oxi ho tan s gy ra hin tng phng bn do vi khun dng s pht trin, lm cho bn xp, kh lng. Vic cung cp oxi cn c tc dng to ra ng nht cc pha trong thit b, lm r cc khi bng sinh hc ln, gim cc imcht trong thit b, nng cao hiu qu lm sch v rt ngn thi gian lu nc tronh thng.

ho tan ca oxi vo trong nc ph thuc vo nhiu yu t, khng ch phthuc vo phng thc cp kh (cng sut my nn, p lc nn, c trng ca h



36/100


thng phn phi kh), chiu cao ct nc m cn ph thuc vo nhit , tnh chnc thi, t s F/M (ngun dinh dng/lng sinh khi), tc sinh trng, trng hnh thi v sinh l vi sinh vt.

m bo tc oxi ho cc cht bn din ra tt, nng oxi ho tan c

t 2 4mg/l, lng kh cung cp 45 90 m3/kg .- pH

pH ca nc thi c nh hng ln n cc qu trnh ha sinh ca vi sinh vqu trnh to bn v lng. Di pH ti u cho x l hiu kh nc thi t 6,5 - 8,5.

m bo pH trong khong trn, trong thc t trc khi cho nc thi vo bx l sinh hc hiu kh, ngi ta thng iu ho lu lng, iu chnh gi tr pH b iu ho.

- Nhit Nhit nh hng ti hot ng ca vi sinh vt. Mi vi sinh vt cng c m

khong nhit ti u, nu tng nhit qu ngng s c ch hot ng csinh vt hoc b tiu dit hay to bo t.

nh hng ca nhit n DO:+ Khi nhit tng DO gim v vn tc phn ng tng ln.+ Khi nhit gim DO tng nhng ngc li vn tc phn ng gim.

Trong b Aeroten nhit ti u l 20 270C, nhng cng c th chp nhn

nhit 16 370

C. [11]nh hng ca nhit ti tc phn ng sinh hc th hin qua biu thc:

R T = R 20.(T 20) Trong :

+ R T, R 20: tc phn ng nhit T0C v 200C+ : h s nhit (c gi tr t 1,00 1,04 )+ T: nhit x l (0C ).

- Thnh phn dinh dng

Thnh phn dinh dng trong nc thi ch yu l ngun Cacbon (th hiBOD), cng vi N (thng dng NH4+) v P ( dng mui photphat) l nhngnguyn t a lng; ngoi ra cn c cc nguyn t vi lng nh: Mg, Fe, Mn...

T l cc cht dinh dng ph hp l C : N : P = 100 : 5 : 1Thiu dinh dng trong nc thi s lm gim mc sinh trng, pht tri

tng sinh khi ca vi sinh vt, th hin bng lng bn hot tnh to thnh gikm hm v c ch qu trnh oxy ho cc cht hu c gy nhim bn.

Nu thiu N mt cch ko di, ngoi vic cn tr qu trnh sinh ho cn lmcho bn hot tnh kh lng, cc ht bng b phng ln tri ni theo dng nc ra



37/100


lm cho nc kh trong v cha mt lng ln vi sinh vt, lm gim tc sintrng cng nh cng oxy ho ca chng.

Nu thiu P, vi sinh vt dng si pht trin v cng lm cho bn hot tnh lnchm v gim hiu qu x l.

- Cht c i vi VSV Cc cht c hu c, v c, c bit l cc kim loi nng, cc ion halogen c

kh nng c ch thm ch lm v hot h enzym oxi ha kh vi sinh vt. V thcn phi x l trc cc cht c ny.

Nng mui v c cn khng ch sao cho < 10 g/l.- Hm lng cc cht rn l lng (SS ) dng huyn ph

Nu nng cht l lng khng qu 100mg/l th loi hnh x l thch hp l b lc sinh hc v nng khng qu 150mg/l l x l bng aeroten s cho hiqu phn hu cc cht hu c nhim bn l cao nht. [8]

Hm lng cht rn l lng cao thng lm nh hng ti hiu qu x l. Vvy, cn phi qua lng trong giai on x l s b mt cch y loi b ccn ln v mt phn cc cht rn l lng.

- Nng cht bn hu c trong nc thi Nng c cht trong mi trng nh hng nhiu ti i sng ca vi sin

vt. Vi sinh vt s b c ch v b km hm qu trnh hot ng sng trong trn

hp nng cht bn hu c cao hn nng cho php.i vi Aeroten thng thng th hm lng BOD = 500mg/l; i vi Aerotenkhuy trn hon chnh th BOD < 1000mg/l. Nu BOD cao qu th cn pha longnc thi hoc qua x l k kh trc ri qua x l hiu kh sau.

- Hm lng sinh khi (MLSS ) v t l F/M Hm lng sinh khi trong b sinh hc hiu kh thng dao ng t 500

3000mg/l. Tu theo hm lng v bn cht ca cht nhim trong nc thi cnnh hot lc ca bn hot tnh m hm lng sinh khi s khc nhau:

+ Cc h thng cao ti c th s dng hm lng sinh khi cao t 1500 3000mg/l.

+ Vi h thng Aeroten thng thng th hm lng sinh khi dao ngtrong khong t 500 1500mg/l.

T l F/M (Food/ microorganism = cht thi/ vi sinh vt): l mt thng squan trng nh hng n qu trnh sinh trng v pht trin ca vi sinh vt hikh.

+ Nu F/M


38/100


+ Nu F/M >1 : Vi sinh vt pht trin sinh khi, khng to nha bo nnkhng kt dnh vi nhau li thnh bng, kch thc bng bn gim, bn kh lnglm nc ra sau x l khng t trong yu cu.

+ T l F/M = 0,2 0,6 : To n nh trong qu trnh x l hiu kh.

Cc dng thit b thng gp- Cc cng trnh hiu kh nhn to x l nc thi da trn c s sinh

trng dnh bm ca vi sinh vt lc sinh hc.+ X l nc thi bng lc sinh hc

Nguyn l ca phng php lc sinh hc l da trn qu trnh hot ng ca vsinh vt mng sinh hc, oxy ho cc cht bn hu c trong nc. Cc mng sinhc l tp th cc vi sinh vt (ch yu l vi khun) hiu kh, k kh v tu tin. Cvi khun hiu kh tp trung lp ngoi ca mng sinh hc, y chng pht triv gn vi gi mang l cc vt liu lc (c gi l sinh trng dnh bm).

Trong qu trnh lm vic, cc vt liu lc tip xc vi nc chy t trn xunsau nc thi lm sch c thu gom x vo b lng bc 2. Nc thi vo lng bc 2 c th ko theo nhng mnh v ca mng sinh hc b trc ra khi lc lmvic. Trong thc t, mt phn nc qua b lng c quay tr li lm nc plong cho cc loi nc thi m c trc khi vo b lc v gi nhit cho mnsinh hc lm vic.

Cc cht hu c nhim bn trong nc thi b oxi ha bi qun th vi sinh v mng sinh hc. Mng ny thng dy khong 0,1 0,4mm. Cc cht hu c trht b phn hy bi vi sinh vt hiu kh, sau thm su vo mng, nc ht oxha tan v s chuyn sang phn hy bi vi sinh vt k kh. Khi cc cht hu c ctrong nc thi cn kit, vi sinh vt mng sinh hc s chuyn sang h hp ni bv kh nng dnh kt cng gim, dn dn b v cun theo nc lc. Hin tng ngi l trc mng. Sau lp mng mi li xut hin.

Vt liu lc kh phong ph : t dm, ong, vng kim loi, vng gm, than, than cc, g mnh, cht do tm un ln...

Hnh 2.2. Cc qu trnh trong b lc sinh hc[8].


Vt lium

Vng ymkh

Vng hiukh

CHC cacbon

DOSn phm cui

Khng kh

Dng nc thiMng sinh hc Mng cht lng


39/100


Lc sinh hc ang c dng hin nay chia lm 2 loi:+ Lc sinh hc vi vt liu tip xc khng ngp trong nc,+ Lc sinh hc vi vt liu tip xc t ngp trong nc.

Phng php lc c u im l: n gin, ti lng cht gy nhim thay

trong gii hn rng trong ngy, thit b c kh n gin v tiu hao t nng lngnhng cng c nhc im l hiu sut qu trnh ph thuc r rt vo nhit khng kh, chiu dy mng sinh hc, tc oxi ha, cng h hp ca vi sinvt, bn cht cc cht hu c, c tnh b lc, thm t ca mng

- Cc cng trnh hiu kh nhn to x l nc thi da trn c s sinh trngl lng ca vi sinh vt k thut bn hot tnh.

Trong qu trnh x l hiu kh, cc vi sinh vt sinh trng trng thi huyn ph. Qu trnh lm sch Aeroten din ra theo mc dng chy qua ca hn hp nthi v bn hot tnh c sc kh. Vic sc kh nhm m bo hai qu trnh l nc bo ho O2 v duy tr bn hot tnh trng thi l lng.

Nc thi sau khi c x l s b cn cha phn ln cc cht hu c dng ho tan cng cc cht l lng i vo Aeroten. Cc cht l lng ny l mt scht rn v c th l mt s cht hu c cha phi l dng ho tan. Cc cht l ll ni vi khun bm vo c tr, sinh sn v pht trin, dn thnh cc ht c bng. Cc ht ny dn dn to v l lng trong nc. Cc ht bng cn ny cn

chnh l bn hot tnh. Bn hot tnh l tp hp nhng vi sinh vt c trong nc thhnh thnh nhng bng cn c kh nng hp th v phn hu cc cht hu c khi cmt ca O2.

+ B Aeroten thng (truyn thng) Nc thi sau khi c tch cn trong b lng s cp s c dn vo v tr

vi bn hot tnh tun hon u b aeroten. Tip xy ra cc phn ng khonha cc cht hu c, tng hp sinh khi v nitrat ha bi cc enzym ca vi sinh vtrong iu kin c oxi. Sau khi ra khi b, nc thi c lm sch.

Nhc im ca b ny l ch p dng x l nc thi c BODv < 400mg/l.+ B Aeroten lm thong ko di

B ny c thit k vi ti trng cht hu c thp, ch s F/M thp, thi gilm thong thng 20 30h.

B ny s dng x l nc thi cng nghip c cng sut < 3500 m3/ngy.Trong b ny, do vi sinh vt b b i nn thc hin qu trnh oxy ha t bo tngdn ti nc thi ra c x l trit , lng bn thi t.

+ Mng oxy ha



40/100


Mng oxy ha l mt dng ci tin ca b aeroten khuy trn hon chnhlm vic trong ch lm thong ko di vi hn hp nc thi v bn hot tnchuyn ng tun hon v lin tc trong mng (trng thi l lng).

Khi hot ng, trong mng oxy ha s hnh thnh 2 vng c bn :

Vng oxic : qu trnh oxy ha cacbon v nitrat ha xy ra khi c oxy.Vng anoxic : l vng thiu kh, xy ra qu trnh denitrat ha.

+ Aeroten ti trng caoB ny c p dng khi yu cu nc sau x l t tiu chun ct B hoc c

C. Khi nc thi vo aeroten s c trn vi 10 15% bn tun hon v hhp ny s c a vo b lm thong trong thi gian 1 3h.

+ B Aeroten kt hp lng hot ng gin on theo m (SBR-Sequencing Batch Reactor)[6]

Cc giai on hot ng din ra trong mt ngn b (hnh 2.3) bao gm: lmy nc thi, thi kh, lng tnh, x nc thi v x bn d. Trong bc mkhi cho nc thi vo b, nc thi c trn vi bn hot tnh lu li t chu trc. Sau y, hn hp nc thi v bn c sc kh bc hai vi thi gian thkh ng nh thi gian yu cu. Qu trnh din ra gn vi iu kin trn hon tov cc cht hu c c oxy ho trong giai on ny. Bc th ba l qu trnh ln bn trong iu kin tnh. Tip n, nc trong nm pha trn lp bn c x

khi b. Bc cui cng l x lng bn d c hnh thnh trong qu trnh thkh ra khi ngn b, cc ngn b khc hot ng lch pha m bo cho vic cucp nc thi ln trm x l nc thi lin tc.

Cng trnh SBR hot ng gin on, c chu k. Cc qu trnh trn nc thivi bn, lng bn cn... din ra gn ging iu kin l tng nn hiu qu x nc thi cao. BOD ca nc thi sau x l thng thp hn 50 mg/l, hm lncn l lng t 10 n 45 mg/l v N-NH3 khong t 0,3 n 12 mg/l. B aeroten hotng gin on theo m lm vic khng cn b lng t hai. Trong nhiu trn

hp, ngi ta cng b qua b iu ho v b lng t mt. [6]



41/100


NT vo

Lm day

Thoi kh

Xa nuoc

thai

LangXa bn du

1

2

3

4

5

Hnh 2.3. Cc bc ca b aeroten hot ng gin on [6].

H thng aeroten hot ng gin on SBR c th kh c nit v pht phsinh ho do c th iu chnh c cc qu trnh hiu kh, thiu kh v k kh trong b bng vic thay i ch cung cp xy. Cc ngn b c sc kh bng my nkh, my sc kh dng Jet hoc thit b khuy trn c hc. Chu k hot ng cngn b c iu khin bng rle thi gian. Trong ngn b c th b tr h thvt vng, thit b o mc bn...

B aeroten h SBR c u im l cu to n gin, hiu qu x l cao, khc cc cht dinh dng nit, d vn hnh. S dao ng lu lng nc thi t hng n hiu qu x l. Nhc im chnh ca b l cng sut x l nc thnh. b hot ng c hiu qu ngi vn hnh phi c trnh v theo dthng xuyn cc bc x l nc thi.

ng dng cho nc thi ngnh biaDo c th nc thi ngnh bia c s dao ng ln v lu lng cng nh

nng gia u v cui ca sn xut, c bit ba thng gip tt lng nc thtng cao do cng sut sn xut tng 20 30% cng sut trung bnh. Do , vic sdng b SBR ny ch ng hon ton c trong vic x l nc thi khi lu lthi ra trong ngy gim i so vi cng sut thit k hoc c s thay i ln v th phn ca nc thi.

u, nhc im khi s dng phng php hiu kh [4, 8]- u im:

+ Thi gian x l nhanh, thi gian lu bn v nc nh thch hp vi ccnh my c lu lng dng thi ln v hm lng BOD khng cao lmhoc c th kt hp x l ln 2 sau b ym kh nu cn hm lng BODcao.+ Hiu sut x l kh cao, chu c s dao ng ln ca lu lng vcht lng nc thi.



42/100


+ Bn sau x l c th tn dng lm phn vi sinh.+ H thng c cp kh lin tc nn nc sau x l m bo clng oxy ho tan.+ Hn ch sinh ra kh c, mi thi.

+ Phng php ny c th loi b BOD trong thi gian ngn, c th khc N, P. Hiu sut kh BOD c th ln ti 99%.+ Bn d lng.

- Nhc im:+ Tn nng lng cho qu trnh sc kh.+ Lng bn sinh ra nhiu hn so vi ym kh.+ Thch hp i vi nc thi c BOD < 1000mg/l v hm lng chtc thp.+ Kh phn hu c mt s cht bo v cc cht hu c mch vng.

Phng php x l sinh hc ym kh, hiu kh (iu kin nhn to) rt thchp cho nc thi cc ngnh cng nghip thc phm ni chung v ngnh bia niring. Vic ng dng v la chn cng ngh cng nh thit b ca phng php ntrong x l nc thi ngnh bia (Cng ty c phn bia Si Gn Min Trung), xinc trnh by c th trong Chng III.



43/100


CHNG IIIC TRNG DNG THI V LA CHN CNG NGH X L

NC THI CHO NH MYIII.1. c trng dng thi

Ty theo tnh cht, c th v mc nhim ca tng ngun nc thi troncng ngh sn xut bia (s hnh 1.3), ta c th phn thnh 3 nhm sau y:

1. Nhm 1: Nc thi coi nh sch. Nc lm lnh, nc ngng, y l ngun nc thi t hoc gn nh khn

gy nhim nn c kh nng tun hon s dng li.2. Nhm 2: Nc thi sinh hot.

Lng nc dng cho nhu cu sinh hot ca nhn vin iu hnh v tham giasn xut trong cng ty khong 250 ngi. Tiu chun nc dng cho sinh hot ccng nhn c tnh theo quy nh 20 TCN-33-85 B Xy Dng nh sau:

Bng 3.1. Tiu chun nc dng cho sinh hot ca cng nhn[20 TCN-33-85]

Loi phn xng Tiu chun dng nc(lt/ngi/ca)H s khng iu ha

(K gi)Phn xng nngQ ta nhit >20 kcal/m3.h 45 2,5

Phn xng khcQ ta nhit


44/100


- Nc thi t cng on hon tt sn phm: Lc, bo ha CO2, chit chai,ng np, thanh trng.

Nc thi ch yu t cng on ny l nc v sinh thit b lc, nc ra chv tc cha. y cng l mt trong nhng dng thi c nhim ln trong sn xu

bia. Nc thi t cng on ny c cha bt tr lc, mt t b men, bia cn li t

bao b ti s dng, bia ri vi trong qu trnh chit, pH cao- Nc ra sn cc phn xng, nc thi t ni hi, nc t h thng l

lnh c cha hm lng chlorit cao.- Xt v axit thi ra t h thng CIP, xt t thit b ra chai. Dng thi ny

c lu lng nh v cn thu hi ring x l cc b, tun hon ti s dng chcc mc ch khc.

Trong sn xut bia, cng ngh t thay i t nh my ny sang nh my khc,s khc nhau c th ch l s dng phong php ln men chm hay ni. Nhng skhc nhau c bn l vn s dng nc cho qu trnh ra chai, lon, my mc thi b, sn nh iu dn n ti lng nc thi v hm lng cc cht nhica cc nh my bia rt khc nhau. cc nh my bia c bin php tun hon ncv cng ngh ra tit kim nc th lng nc thp.

Hin nay tiu chun nc thi to thnh trong qu trnh sn xut bia l 8 14

lt nc thi/lt bia [6]; ng thi lng nc thi to thnh trong qu trnh sn xu bia ca Cng ty C phn Bia Si Gn Min Trung (cng sut 50 triu lt bia/nmc tnh khong 8 lt nc thi/lt bia. Do , nu nng cng sut nh my ln 10triu lt bia/nm th tng lng nc thi nhim trong qu trnh sn xut t cngun nu trn c tnh trong khong 2600 3200 m3/ngy. Tuy nhin, do c thca ngnh bia, vo ba thng gip tt th cng sut c th tng t 20 30% cng sutrung bnh (tc cng sut nh my ba thng gip tt t 120 130 triu lt bia/nm)Do , tng lng nc thi ln nht c tnh c th ln ti 4000 m3/ngy m.

y cng chnh l lu lng thit k h thng x l nc thi.Cn c vo kt qu phn tch nc thi thc t hin nay ca nh my Bia S

Gn Min Trung (cng sut 50 triu lt bia/nm) v tham kho mt s kt qu phn tch nc thi ca cc nh my bia trong nc v cc ti liu c lin quan ththnh phn ch yu nc thi ca nh my bia c c tnh trung bnh nh sau:

- BOD5 (mg/l) : 1300-1700- COD (mg/l) : 2000-3000- TSS (mg/l) : 400-800- pH : 8,5 11- Tng Nit (mg/l) : 100



45/100


- Tng Phtpho (mg/l) : 8- Ti trng nc thi (kg BOD5/m3 bia): 3,5 4,5

III.2. La chn cng ngh x l nc thi cho nh myCc thng s u vo v tiu chun dng ra ca nc thi nh my bia Si

Gn Min Trung cng sut 100 triu lt bia/nm: Bng 3.2. Cc thng s u vo v tiu chun dng ra ca nc thi nh my

Thng s Nc thi uvo

Nc thi sau x l (QCVN24 2009) ct B

Lu lng(m3/ngy.m)

4000 4000

COD (mg/l) 2500 100BOD (mg/l) 1500 50

SS (mg/l) 600 100 pH 8,5 11 5,5 9Tng Nit (mg/l) 100 30Tng photpho (mg/l) 8 6

La chn s dy chuyn cng ngh x l nc thi cho cc nh my cngnghip thc phm ni chung v nh my bia ni ring l mt bi ton kinh t, kthut ph thuc vo nhiu yu t:

Lu lng v c trng ca nc thi. Yu cu nc thi sau x l . Din tch v v tr t ai s dng xy dng trm x l nc thi. iu kin kinh t v k thut.

Nh vy, t s phn tch c tnh nc thi ca nh my ta thy ngun nthi pht sinh t nh my c ngun gc, thnh phn v tnh cht khc nhau, c pht sinh t nc lm mt, nc ngng, nc v sinh cc thit b nu, lc, ln menc ra sn, nh xng, nc ra chai, tc cha Nc thi ca nh my bia ni

chung cha hm lng cht h c cao trng thi ho tan v trng thi l lngch yu l cc hiratcacbon, protin, cc axit hu c, l cc cht c kh nng phnhu sinh hc gy mi hi thi, lng cn, gim nng oxy ho tan trong ncngun khi tip nhn chng. Mt khc, cc mui nit, phtpho trong nc thi bia dgy hin tng ph dng cho cc thu vc; t l BOD5/COD = 0,5 0,7 thch hpvi x l bng bin php sinh hc.

X l nc thi bng bin php sinh hc gm x l sinh hc hiu kh v x lsinh hc ym kh.



46/100


X l sinh hc bng vi sinh hiu kh (phng php s dng bn hot tnh)thng ch thch hp cho x l nc thi c nng COD, BOD5 thp (BOD5 2000 mg/l). Vnc thi ca nh my bia Si Gn Min Trung c thnh phn nhim nh trn phn tch th khng th x l trc tip bng phng php sinh hc hiu kh Tuy nhin, nu ch x l bng phng php sinh hc ym kh th nc thi sau xl khng t tiu chun thi (QCVN 24 2009 ct A, ct B) do qu trnh phn huym kh khng trit v hiu sut x l ym kh cao nht cng ch t 70 85%[13].

V vy, sau phn hu ym kh thng c h thng phn hu hiu kh x ltrit cc cht nhim cn li. Do , trong n ny chn phng php x lsinh hc ym kh kt hp hiu kh x l nc thi nh my bia.

Vic la chn x l ym kh kt hp hiu kh l v: Nc thi ca nh my biSi Gn Min Trung theo phn tch c mc nhim ln do x l ym khnhm gim mc nhim trc khi a vo x l hiu kh, va gim c ttch b hiu kh va gim c th tch bn sinh ra, thu hi nng lng di dn

biogas, gim tiu th in nng cho vic cp kh

III.3. S cng ngh h thng x l nc thi c la chn(hnh 3.1)Thuyt minh1. Tch rc th, gom nc thi Nc thi sn xut t cc phn xng sn xut v nc ra chai, theo n

mng dn chy v khu x l. Phn nc xt ra chai s c thi t t vo thng, khng lm cho pH nc thi tng. B thu gom c xy dng trong cng

mt bng ca khu x l. Nc thi trc khi i vo b thu gom, phn rc th ckch thc ln s c gi li ti song chn rc th t nghing 600 ngn tch rc.Rc tch ra s c cng nhn vn hnh gom vo thng cha v mang i ni quinh ca nh my.

Nc thi t h gom c bm ln b cn bng nh 2 bm chm (1 bm d phng hoc hot ng ng thi). Cc bm vn hnh hon ton t ng nh hthng iu khin.



47/100


Hnh 3.1. S h thng x l nc thi xut ti Cng ty BiaSi Gn-Min Trung.

Ghi ch: ng nc thi ng rc ng bn ng kh


Nc thi trongqu trnh sn xut

THIT B TCH RC TH

B YM KH UASB

H GOM

THIT B TCH RC TINH

B IU HA

B HIU KH SBR

B KH TRNG

Nc x l, ra cng thot

Thng rc

My p bn

B nn bn

B cha bn

ng bao bn kh

Bm

Sc kh

Ha cht

Bm

Dinh dng

o lu lng

Bm

Tch nc d

Decanter

iu chnh pH

Nc xt ra chai

Thu kh

sinh hc

iu chnhthi t t

B LNG

Sc kh

47


48/100


2. Tch rc tinh v iu ha cn bng Nc thi t h gom trc khi bm vo b cn bng, c i qua 1 thit b

tch rc tinh dng trng quay (RDS) c kch thc khe chn 1mm. Ti y, ton brc c kch thc >1mm s c gi li trn b mt trng v c dao gt a

ngoi v vo thng cha rc, phn nc i vo b iu ha. Nc thi sau khi qua thit b tch rc tinh tip tc chy qua b cn bng. B

cn bng phi c th tch ln m bo iu ha nng thnh phn cc cn nh cho qu trnh x l, cng nh iu ha lu lng.

vi sinh vt sinh trng v pht trin tt, qu trnh x l sinh hc ym khi hi pH = 6,5 7,5. V th, cn phi duy tr kim, khng cho pH gim xundi 6,2 v nng cc cht dinh dng m bo t l COD : N : P = 350 : 5 : 1Do , ti b iu ha, nc c iu chnh pH v gi tr thch hp nh b pHcontroler. Ty theo gi tr pH trong nc thi m bm nh lng xt v axit cho ph hp. Ngoi ra, chng li hin tng sinh bt trong b ym kh, b hiu knc thi c chm thm mt lng cht chng to bt nh bm nh lng.

to kh nng ng u cc cht trong nc thi v trnh phn hy ym kgy mi kh chu, b iu ha c sc kh nn t ngoi vo.

3. B lng Nc thi t b iu ha c bm ln b lng. Ti y, hm lng cht rn

lng SS, BOD, COD gim xung nhm gim ti v m bo iu kin u vo ccc cng trnh x l sinh hc pha sau. Nc thi sau khi qua b lng c bm sang b x l ym kh UASB. B

lng y b c a sang b cha bn.4. X l sinh hc ym kh (UASB)Ti b UASB nc thi s c phn phi u trn din tch y b qua h

thng ng phn phi c c l. Nh hn hp bn ym kh trong b m cc cht hc ho tan trong nc c hp th, phn hu v chuyn ho thnh kh (khong 70

80 % l CH4, 20-30% l CO2). Bt kh sinh ra bm vo ht bn cn ni ln trn lmxo trn gy ra dng tun hon cc b trong lp cn l lng. Khi ht cn ni lgp tm chn kh, kh s c thot ln trn v c thu vo h thng thu kh mta pha trn thnh b cn cn ri xung di. Hn hp bn nc tch kh i vngn lng. Ti y bn lng xung di y qua ca phn phi tun hon li vn phn ng ym kh, phn bn d s c a sang b cha bn. Nc thi ra khiUASB c hm lng cht hu c tng i thp c chy trn qua b AeroteSBR thng qua mng thu nc.



49/100


5. B x l sinh hc hiu kh theo m (SBR)T b UASB, nc thi chy tng m vo b SBR qua tuyn ng c lp va

in iu khin t ng. Giai on x l sinh hc hiu kh chnh xy ra ti yQu trnh oxy ha cht bn thc hin nh bn hot tnh hiu kh. Bn hot tn

hiu kh l tp hp cc vi sinh vt c kh nng oxy ha cc cht hu c trong nthi thnh CO2, nc v cc cht v c khc. gi cho bn hot tnh trng thil lng v cung cp oxy cho qu trnh oxy ha cc cht hu c, di y m b c lp h thng phn phi kh. vi sinh vt phn hy ht cc cht hu c trong nc thi th th tch b sinh hc phi ln v thi gian lu li trong b d

Hiu qu x l ti b SBR ph thuc vo cc yu t sau: Thnh phn cc chtrong nc thi, pH, hm lng oxy, lng bn, trng thi hot tnh ca bn

Trong qu trnh sinh trng v pht trin ca vi sinh vt hiu kh, nhu cukhng th thiu c l oxy. vi sinh vt hot ng tt, lng oxy ha tan tronnc b sinh hc t nht phi t 2 4 mg/l. Ty theo nhit ca mi trng mlng oxy trong nc c khc nhau. Lng oxy c cung cp y l ngun oxkhng kh thng qua thit b cp kh v y b c lp mt dn ng khuch tn kh Nc thi lu li trong b SBR v hu ht cc cht hu c u c phn hy; hlng BOD gim v hm lng cc thng s khc t tiu chun yu cu ca nthi sau x l (QCVN 24 2009 loi B). Tuy nhin, trong nc thi vn cn ch

mt lng ln bn hot tnh cn c tch ra khi nc thi trc khi thi ra mtrng. V vy, nc thi sau chu k sc kh s c yn nhm lng tch bPhn nc trong s c gn ra khi nh thit b gn nc b mt Decanter sau i vo b kh trng. Phn bn lng s tham gia vo chu trnh x l mi, lng bnd s c bm qua b nn bn v tip tc x l.

Qu trnh hot ng ca h thng t lc nc thi vo n khi ra khi b SBc iu khin hon ton t ng t trung tm iu khin. (qu trnh ny cng cth vn hng bng tay).

6. Kh trng Nc thi sau khi qua b SBR v c lng gn trong t mt s tiu chu

ca nc thi nhng trong nc thi vn cn cha vi sinh vt v mm bnh. V v m bo an ton, nc thi cn c kh trng trc khi thi vo mi trn m bo thi gian tip xc gia nc thi vi clo hot tnh, th tch ca b ktrng phi ln nc thi lu li trong b kh trng ti thiu l 30 45 pht.

Hiu qu v kinh t nht l kh trng bng dung dch hypoclorit. Nng clohot tnh s dng kh trng nc thi sau x l thng thng l 4 5ppm. Qutrnh cung cp clo c thc hin nh 2 bm nh lng (1 d phng) v 1 mixe



50/100


ha trn. Bm nh lng hypoclorit c iu khin bng tn hiu ca thit decanter ly nc ra t b SBR.

7. B cha bn ym kh v b nn bn hiu kh Lng bn d t b SBR c bm vo b nn bn nh bm chm. Bn sau

khi c bm y b nn s c yn. Khi , bn s c tch ra lm 2 ph phn bn c lng xung y v a sang thit b tch bn cn phn nc tron pha trn c bm v h gom.

Lng bn d t b ym kh v b lng bc 1 c bm vo b cha bn.8. Thit b p bnVic x l cn, bn trong x l sinh hc l ht sc cn thit. Nu x l khn

tt s ln men ym kh sinh mi hi thi, gy nhim mi trng xung quanh. trnh tnh trng ny, lng bn d s c lm kh bng thit b p bn.

Bn t cc b c bm chuyn dng loi trc vt bm vo ngn ha trn cthit b p bn. Ti y c b sung lng ha cht polymer bng h thng bm nlng. Bn ha trn vi ha cht keo t c nh lng bng bm nh lng, sa bn c bm ln li lc. Qu trnh lm kh bn c thc hin ti y. Ph bn kh c gi li trn li v

Documents

Đồ án tốt nghiệp đã hoàn thành