NGHIEN CUtJ XtT LY NlTOfC
T H A I C H A NNUOI LON SAU BIOGAS
B A N G
PHlTONG
P H A P L O CSINH HOC NHO GIOT
• • •
Nguyen Hoai Chau, Tran Manh Hai Vien Cong nghe moi trudng 18- Hoang Quoc Viet, Cau Giay, Ha Noi
Email: chauhoainguyen(^yahoo.com Tom tat:
Hien nay, a Viet Nam nude thdi chdn nudi lan chit yiu dupe xie ly bdng hdm phdn hiiy yim khi (hdm biogas), sau qud trinh ndy cdc thdnh phdn gay d nhiim mdi trudng (TSS, COD, BOD, tdng N, tdng P, ...) vdn cdn d mice rdt cao vd cdn phdi dupe xir ly tiip trudc khi cd the thdi ra mdi trudng. Trong bdi bdo ndy trinh bdy kit qud nghiin cicu quy trinh xie ly nude thdi trang trgi chdn nudi Ipn sau khi dd duac xic ly sa bd bdng hdm Biogas. Nghien cicu ndy duac tiin hdnh vdi ngudn nude thdi sau biogas tgi trang trgi chdn nudi Ipn cua dng Nguyin Vdn Thanh xd Ddng Hung - VTnh Yen - Vinh Phuc bdng cdng nghi: thiiu khi ^^ Ipc sinh hpc nhd gipt =^ hd sinh hpc vdi cdc thdng sd cdng nghi: luu lupng 0,2 m^/h, thdi gian luu nude tgi bi thiiu khi Id 4h, tgi hd sinh hpc la 10 ngdy, diin tich bi loc sinh hpc nhd gipt Im . Vdi cdc thdng sd ddu vdo ciia nude nhu sau: TSS = 1228 mg/l; COD = 1195mg/l; BOD = 534 mg/l; N-NH4 = 405 mg/l;^ N,o,ai = 518 mg/l and Ptoiai = 67 mg/l thi chdt luang nude sau khi duac xie ly bdng qud trinh trin tuang icng la 108; 252; 116; 118; 185 vd 22, hieu sudt xie ly ldn luat la TSS ~ 90%; COD -80%; BOD ~ 78%; N-NHf ~ 71%; ZN ~ 64%o vd EP ~ 66%.
Abstract:
Currently, in Vietnam swine wastewater mainly treated with anaerobic decomposition tunnel (tunnel biogas), after this process the components of environmental pollutants (TSS, COD, BOD, total N, total P, ...) is still very high and require further processing before they can be discharged into the environment. This paper presents research results of swine wastewater after treatment a biogas pit. This study was conducted with swine wastewater come out ojf biogas in the pig farm of Mr. Nguyen Van Thanh, Dong Hung Commune - Vinh Yen - Vinh Phuc by technology: anoxic -> biological trickling filter -> biological lagon, with following technologycal parameters: water flow 0.2 m/h, residence time in anoxic tank ~ 4h, in biological pond ~ 10 days, cross section of biological trickling filter tank Im . With the parameters input to the water as follows: TSS = 1228 mg/l; COD = I195mg/l BOD = 534 mg/l; N-NH4 = 405 mg/l; N,o,ai = 518 mg/l and P,oiat = 67 mg/l, the water quality after the treatment process exhibit the respective parameters 108; 252; 116; 118; 185 and 22; performance efflciencifs are TSS ~ 90%o; COD ~ 80%; BOD ~ 78%; N-NH/ ~ 71%; ZN ~ 64% and EP ~ 66%.
1. MO DAU
Trong nhiing nam gin day, nganh chan nuoi Viet Nam da phat triln dang kl. TIC do tang trudng binh quan giai dgan 2001-2007 dat 8.9% [1]. Lugng chit thai tir hoat dong chan nuoi thai ra hang nam khoang 80 trieu tin chit thai rin va hang ti m^ chat thai long [2]. Tuy nhien, viec xir ly chit thai d hau hit cac co sd chan nuoi Ign chi mdi dimg d miic sir dung he thong him biogas [3]. Sau qua trinh xir ly nay nude thai vin con chiia nhieu tac nhan gay 6 nhilm moi trudng d miic do cao: COD = 1251 ^ 3397 mg/l; BOD = 783 ^- 1339 mg/l; Ptotai = 57 H- 99 mg/l; Hotai = 205 ^ 333 mg/l [3, 4].
Qua sl lieu neu tren co thi khing dinh ring nude thai sau biogas can phai tilp tuc dugc xu- ly trudc khi thai ra moi trudng va cin phai xir ly ding thai nhieu tac nhan 6 nhiem dac biet la COD, nito va phit pho. Xir ly nude thai giau dinh dudng bang cac qua trinh vi sinh da va dang dugc ap dung rgng rai. Nhilu qua trinh sir dung vi sinh dugc ap dung nhieu hien nay nhu:
Pheredox A/0; quy trinh A2O- Ki khi -> thiiu khi -> hiiu khi; quy trinh Bardenpho 5 giai dgan- Ki khi -> thiiu khi -> hiiu khi -> thiiu khi -> hiiu khi; quy trinh UCT- University Cape Town;
VIP- Virginia Initiative Plant va Phostrip Process [7] ciing nhu cac ky thuat xir ly khac nhu: ho sinh hgc, lgc sinh hgc dat ngap nude,... Cac ky thuat nay dua vao hgat dgng cua cac loai vi sinh vat, thuy sinh vat de phan buy cac chat gay 6 nhiem. Sir lira chgn cdng nghe xir ly nude thai chan nuoi Ign phu thudc vao cac dieu kien ha tang ca sd, tai chinh .... Thuc te cho thay da so co sd chan nuoi Ign deu cd hoac se xay dung ham biogas de xii ly nude thai trudc khi dua ra moi trudng. Nghien ciiu nay danh gia kha nang ling dung cua ky thuat lgc sinh hgc nho gigt trong viec xir ly nude thai chan nuoi sau biogas.
2. THU'C NGHIEM 2.1 Nguon nu-dc thai
Nguon nude thai dugc sir dung trong nghien ciiu nay dugc lay tir nude thai sau biogas tai trang trai chan nuoi Ign nha ong Nguyen Van Thanh - xa Ddng Hung - Vinh Yen - Vinh Phiic. Cac thong sl chinh cua nude (mg/l) nhu sau: TSS = 1133 ^ 1323; NH4"' = 385 ^ 425;
Ntotai = 497 -r 539; Ptotai = 63 ^ 71; COD = 1095 ^1295; BOD = 486 ^ 582.
2.2. Thi nghiem
Thi nghiem dugc thuc hien tai hien trudng, tren he pilot nhu d hinh 1.
G) Q
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Phan huy
thieu khi V Loc sinh hpc nho giot
<-
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Nuac tuan hoan
Chi chii: 1. 2, 3, 4: Cdc diim lay mdu
B§ lang 2
Ho sinh hoc
LTinh 1: Sa dd cdng nghi hi xir ly
• < D
Thai ra MT
Cac thong so cua he thong nhu sau:
-^Bi phdn huy thiiu khi: bl phan buy thieu khi ket hgp ngan lang, kich thudc be 2x2.5x1.5 (m)
-I- Bi Ipc sinh hpc: kich thudc 1x1x2,5 (m). Vat lieu mang sir dung la soi nhe d=15-30mm, co 4 Idp vat lieu mang moi Idp day day 25 cm, giira cac Idp co cira thu khi d tuong be. Nude thai dugc tudi len bl mat VLL bing gian Ing due lo lam kieu xuong ca.
-I- Hd sinh hpc: Xay dung hi sinh hgc tiiy tien kich thudc 10x4x1,2 m.
Mo td cong nghe: Nude thai tir he thing bl Biogas da co dugc tach ra mgt phan (3-5 mVngay), dua vl bl thu gom kit hgp bl phan buy thieu khi c6 ngan Ipc. Nude sau be nay dugc bom len bl lgc sinh hpc nho gipt. Nude sau Ipc sinh hpc nho gipt dugc tuan hoan khoang 20-30% luu lugng vl bl ling. Nude thai con lai sau lgc sinh hgc nho gipt tu chay sang ao sinh hpc dang tiiy tien va dugc xu ly bdi cac qua trinh thuy sinh hgc tu nhien nham giam thieu cac chat 6 nhiem.
2.3 Phuong phap phan tich
pH, TDS: sir dung may do da nang SENSION-156 - HACH - My
COD: dugc xac dinh bing phuong phap so mau HACH-1986, 16 cong pha DRB 200- HACH, thiit bi so mau quang dien DR 2800- HACH - My
TSS: dugc xac dinh bing phuang phap so mau HACH-1986, thiet bi so mau quang dien DR 2800- HACH - My
NH4'^: sir dung phuang phap so mau Nesstler, do tren may so mau quang dien DR 2800- HACH - My
Ntotai: xac dinh bing phuang phap 8075- HACH- Nessler Method (Digestion Require), sir dung kit thir Kjeldabl Nitrogen Reagent Set- Cat.No.24953-00, so mau tren may do mau quang dien DR 2800- HACH - My
Ptotai: xac dinh bing phuong phap 8048-HACH- My- PbosVer 3 (Ascorbic Acid). Sir dung boa chit: PbosVer 3 Phosphate Reagent Powder Pillow. Cat.No 21060-69, so mau tren may do mau quang dien DR 2800- HACH - My
3. KET QUA VA THAO LUAN
Sau thdi gian khdi dgng 1 thang, ket qua phan tich cho thay he hgat dgng on dinh, ket qua phan tich chat lugng nude sau xir ly d thdi gian tiep theo nhu sau:
3.1. Ket qua hoat dong d che do khong tuan hoan
Bdng 1: Kit qud phdn tich nude sau xic ly a chi dd khdng tudn hodn TT
1 2 3 6 7 8 9
Chi tiiu pH TSS NH4^
N_t6ng P_t6ng COD BOD5
Dan vi
mg/l mg/l mg/l mg/l mg/l mg/l
Kit qud phdn tich 2
7,62 830 323 431 44 935 475
3 7,67
465 228 289 35 428 201
4 8,01
108 118 168 32,4 352 146
TCN 678:2006 5-9 500 - 150
20 400 300
Ghi chu: 2, 3, 4 - cdc diim ldy mdu; Cdc gid tri dupe tinh trung binh cho 1 tudn
Cac gia tri 6 nhilm trong nude thai sau be ky khi giam dang kl: TSS giam 32%), COD giam 28.87%, XN giam 16.7%, XP giam 16.4%, va sau bl lgc sinh hgc nho gigt cac gia tri nay giam lin lugt la 62%, 64%, 44.2% va 48%. 6 day % cac gia tri dugc loai bo cho thiy chilu hudng tit cua qua trinh xu ly nlu co sir tuan hoan nude sau xit ly.
3.2. Ket qua hoat dong d che do tu^n hoan 20%
Bdng 2: Kit qud phdn tich nude sau xic ly a chi dp tudn hodn 20%
Stt 1 2 3 6 7 8 9
Chi tieu pH
TSS NH4^
N_t6ng P_t6ng COD BOD5
Dan vi
mg/l mg/l mg/l mg/l mg/l mg/l
Kit qud phdn tich 2
1.1\
665 263 351 46 850 405
3 8.01
314 189 237 32 322 125
4 8.11
108 118 185,65
22,4 252 116
TCN-678: 2006
5-9 500
- 150
20 400 300 Ghi chii: 2, 3, 4 - Cdc diem ldy mdu; Cdc gid tri duac tinh trung hinh cho 1 tudn
Lupng nude tuan hoan da lam qua trinh oxy boa cac chat dien ra tot Tion, mac du chua khao sat dugc chi tiet anh hudng cua ty le tuan hoan nhung theo cac tai lieu thi day la mgt ty le kha toi uu.
Bdng 3: Tdng hop hiiu qud xit ly sau cdc qud trinh
Chi tieu
TSS NH4^
N_t6ng P_t6ng COD BOD5
Ddu vdo (mg/l)
1228 405 518 67 1195
534
Be thiiu khi cd ngdn Idng
Hieu sudt '(%) 45.85 35.06 32.25 31.34 21.76 24.16
Cdn lai (mg/l) 665 263 350,94
46 935 405
Bi Ipc sinh hpc nhd gipt Hieu sudt
'(%) 52.78 28.14 32.47 30.43 65.56 76.54
Cdn lai (mg/l)
314 189 237 32 322 125
Hd sinh hpc Hieu sudt
(%) 65.61 37.57 21.67 30.00 21.74 7.20
Cdn lai (mg/l)
108 118 185,65
22,4 252 116
Hieu sudt (%)
91.21 70.86 64.16 66.57 78.91 78.28
Ning do cac chit 6 nhilm con lai la TSS 9%, COD 21%, ^N 36%, XP 33% va vl ca ban cac thong so gay d nhiem chinh nay da dugc xir ly den gan tieu chuan nganh TCN - 678:
2006. Neu tang them the tich ho sinh hgc thi nude thai sau khi dugc xir ly co nhieu kha nang se dat duoc tieu chuan.
Hinh 2: Ndng dd cdc chdt d nhiem tgi tieng giai dogn thdi gian
4. KET LUAN
Ket qua nghien ciiu so bg cho thay phuong phap lgc sinh hgc nho gipt rat kha thi trong viec xir ly nude thai chan nuoi sau biogas vi de van hanh va co chi phi thudng xuyen thap.
Trong dieu kien hien tai ciia cac trang trai chan nuoi d Viet Nam thi he thong xir ly nude thai chan nuoi Ipn theo so do hdm biogas -> loc sinh hpc nho gipt-> ho sinh hpc co the coi la mot giai phap phu hgp de giai quyet van de 6 nhiem moi trudng do nude thai gay ra.
TAI LIEU THAM KHAO
1. Biii Thuc Oanh, (2008), "Phdt triin chdn nudi vd biin phdp bdo vi mdi truang". Hoi thao tap huan bao ve moi trudng trong chan nuoi thii y tai Cue Chan nuoi.
2. "Chdt thdi chdn nudi - Hien trgng vd gidi phdp ", Ky yeu hoi thao, nam 2009.
3. Nguyen Hoai Chau va nnk, (2008), "Ddnh gid muc dp d nhiim mdi trudng tgi mdt sd trang trgi chdn nudi tiiu biiu ", Tap chi KH&CN, sd 46.
4. Vien chan nuoi, (2006), "Diiu tra ddnh gid hien trgng mdi trudng trgi chdn nudi Ipn ".
5. Vien chan nudi, (2006), "Bdo cdo hien trgng mdi truong chdn nudi d mdt sd tinh ".
6. Nguyen Van Phudc, (2007), "Cdc phuang phdp xic ly nude thdi chdn nudi heo ".
7. Le Cong Nhat Phuong, (2007), "Nghien cicu triin khai icng dung xie ly ammonium trong nude thdi nudi heo vdi cdng sudt 20 m /ngdy vd nudi dudng sinh khdi cd nhdm vi khudn Anammox ".
8. Sebastia PUIG BROCH, (2008), "Operation and Control of SBR Processes for Enhenced Biological Nutriel Remove from wastewater ".
9. Mecalf & Eddy: Wastewater engineering, 2005;
10. Joseph Kyambadde, (2005), "Optimizing Processes for Biological Nitrogen Removal in Nakivubo Wetland, Uganda ".
