Nghiên cứu áp dụng kiểm toán chất thải tại xí nghiệp chế biến thủy đặc sản xuất khẩu Hà Nội

NGHIEN CAU AP DUNG KIEM TOAN CHAT THAI TAI XI NGHIEP CHE BIEN THUY DAC SAN XUAT KHAU HANOI N g u y e n Thi Ha, Bui Thi L u a n Khoa Moi trudng, TrUdng DHKHTN, BHQGHN TOM TAT Kiem toan moi trUdng noi chung va Kiem toan chat thai cong nghiep ndi rieng la mot cong cu quan ly mdi dUdc ap dung d nUdc ta mot vai nam gan day Mac du day la cong cu mdi nhung qua cac ket qua ap dung kiem toan tai nhieu cd sd san xuat cho thay cong cu mang lai Idi ich kbong nbd ca ve moi trUdng va hieu qua kinh te Trong cong trinb chung toi tien hanh nghien ciiu ap dung kiem toan chat thai tai xi nghiep Che bien Tbuy dac san xuat khau Ha Noi (F37) vdi muc dich ap dung cong cu kiem toan vao viec giam tbieu chat thai tai xi nghiep n b i m tim nhiing khau ton that nUdc, nguyen lieu de tix diia nhiing phUdng an cho'ng that thoat, giam tbieu chat thai, tang hieu qua cua qua trinb san xuat, dong tbdi cai thien chat lUdng moi trUdng cho xi nghiep va nang cao hieu qua kinh te san xuat kinh doanh Cac noi dung cu the dudi day se dUdc nghien ciiu: 1) Tim hieu day chuyen cong nghe che bien, miJtc tieu thu nUdc, nguyen lieu va cac chat thai phat sinh 2) Tinb toan can b^ng nUdc, can b^ng chat thai r^n 3) Xac dinh cac khau gay lang phi nUdc va cac nguon gay nhiem moi trUdng 4) Xem xet, danh gia cac phUdng an xii ly, giam tbieu lang phi nUdc cua xi nghiep, 63 5) De xuat cac giai phap c6 tinb kha thi nh^m tiet kiem nUdc, giam CTR, xii ly nUdc thai nh^m cai thien moi trUdng va tang cUdng hieu qua kinh te cho xi nghiep I KIEM TOAN CHAT THAI CONG NGHIEP Kiem toan chat thai la mot loai hinh cua KTMT la cong cu c6 gia tri de cac doanh nghiep kiem tra lai kha nang tuan thu cac tieu chuan moi trUdng, giam cac vi pham ve moi trUdng, giam thieu chat thai va tang cUdng kha nang quan ly moi trUdng Kiem toan chat thai la budc d^u tien de giam chat thai va ciing lam giam nhiem moi trUdng N6 la qua trinb kiem tra khach quan cac qua trinh san xuat va chat thai nh4m muc dich giam nguon thai tang s\i dung lai boac loai bo boan toan chat thai Qua kiem toan cac phUdng an giam thieu chat thai dUdc nhan dang, dUdc danh gia, dUdc lUa ebon, dUdc thUc hien va dUdc giam sat Viec thUc h i e n kiem toan giam thieu chat thai cho xi nghiep F37 dUdc thUc hien theo hudng d^n gom bUdc theo giai doan [Trinb Thi Thanh, Nguyen Thi Ha, 2003] Nghien ciiu dUdc thUc hien tai xi nghiep sau hdn thang khao sat hien trang va tinb toan thUc hien cac budc kiem toan vdi tam kiem toan la day chuyen che bien torn va chat thai chinh la nUdc thai va chat thai r^n II CAC VAN Dfi MOI THUY SAN TRU6NG CUA NGANH C H ^ BIEN Qua trinb san xuat che bien thuy san c6 anh hudng Idn tdi moi trUdng dac biet la moi trUdng nUdc va moi trUdng khong Kbong kbi cac khu vUc san xu^'t va khong xung quanh thUdng cbiu tac dong cua cac yeu to gay nbiim nhu mui hoi thoi, mui tanh, HgS, boa chat nhu clo, mercaptan, ure qua trinh phan buy cac chat c6 nUdc thai va phe thai r4n thai qua trinh san xuat Ngoai qua trinh san xuat che bien su( dung bien cac thiet bi lanb de tri boat dong cua cac may nen lanh va day CO the la nguon gay nbiim moi trUdng khong (khi NHg, freon, ) 64 Khdi lUdng chat thai ran thai bd qua trinh san xuat la rat Idn bao gom cac phan nhU: dau; v6 tom; noi tang cac loai ca, mUc; mai mUc; ong mUc; xUdng vay, vay ca Day la cac chat giau chat hiiu cd de p h t o buy sinh hoc c6 tiem nang gay nhiem moi trUdng neu khong cd bien phap thu gom, xcL \i kip tbdi se anh hUdng dang ke den moi trUdng va sxic khoe ngUdi Van de dang quan tam hdn ca san xuat che bien thuy san la van de suf dung nUdc va nUdc thai Qua trinh che bien can mot lUdng nUdc tUdng do'i Idn Nudc thai che bien thuy san cd ham lUdng cac chat ran, cac chat huEu cd de phan buy sinh hoc cao Cac chat ton tai nUdc d dang keo, dang boa tan, dang phan tan lam cho nude thai c6 mau va due Idn Qua trinh phan buy cac chat nUdc tao cac miii khd chiu va doc hai Ngoai nUdc thai c6 mat cac boa chat khii trung nhU clo, javen; cac chat tay riia, chat boat dong be mat dung hoat dong ve sinh nha xUdng Hien van de moi trUdng mdi dUdc quan tam eac cd sd che bien c6 quy mo Idn Con lai hau bet cac cd sd che bien c6 quy mo viia va nhd van de moi trUdng it dUdc quan tam III KET QUA KIEM TOAN CHAT THAI Nhin chung moi trUdng xi nghiep luon dUdc giiJ thong thoang va sach se Trong khu vUc san xuat che bien van de moi trUdng cung da dUdc quan tam Xi nghiep c6 ba cong nhan chuyen quet don va thu gom chat thai ran (khu vUc xung quanh xi nghiep) va chat thai ran san xuat Cong tac ve sinh moi trUdng da dUdc xi nghiep tbUc hien mot each nghiem tuc N g u y e n n h i e n l i e u , nvtdc v a h o a c h a t sxi d u n g Nguyen, nhien lieu Nguyen lieu chinh ciia xi nghiep la tom, mUc, ca cac loai dUdc thu mua tiif cac vung khac nhU: Quang Ninb, Hai Phong, Thai Binh, Thanh Hoa, Nghe An, Ha Tinb Trung binh moi nam xi nghiep thu 65 mua khoang 450 tan nguyen lieu, lUdng nguyen lieu mdi loai thay doi theo tiing nam va phu thuoc vao tbdi tiet Nguyen lieu thu mua nam 2002 dUdc chi bang sau Bang - Li^dng nguyen lieu thu mua nam 2002 N g u y e n , n h i e n lieu sijf dung So Tom cac loai (Tan/nam) 302,7 Muc (Tan/nam) 171,9 Ca cac loai (Tan/nam) 23,7 Tong nguyen lieu (Tan/nam) 498,3 Dien (kWh) 700 000 Dau DO (Lit) 400 STT litdng [Nguon: Phong Ke toan Tai chinh cua xi nghiep F 37] Hod chat Hoa chat svL dung chu yeu la chlorin vdi khoi lUdng khoang 30 kg/ nam Chlorin diing kbit trung nguyen vat lieu, dung cu thiet bi, tiep xuc vdi san pham, ngan chan su phat trien cua vi sinh vat va khong lam anh hudng tdi chat lUdng san pham Ngoai chlorin xi nghiep dung H2O2 de ngam va tay tr^ng mUc nhien lUdng dung khong dang ke Ni/dc Nguon nude sii dung cua xi nghiep la nUdc gieng khoan da qua he thong xd li bao gom: Nude'diing cho sinh hoat, nUdc dung cho san xuat da, nUdc diing ve sinh nha xudng va nUdc dung cho cac cong doan san xuat Hien tat ca cac cong doan san xuat cua xi nghiep deu chua lap dong ho nudc d6 viec tinb toan lUdng nUdc sd dung chi mang tinb chat tUdng do'i Xi nghiep c6 hai may bdm: 66 * May bdm cong suat 30 m /b lam viec trung binh 4h/ngay * May bdm cong suat 12m /h lam viec trung binh 8h/ Tong ludng nUdc bdm mot la: 30 x + 12 x = 216 (m'^), tinb trung binh mot nam tong so'ngay lam viec cua xi nghiep la 200 do lUdng nude khai thac mot nam c6 the Udc tinb nhu d bang Bang 2- Li^tfng nUdc suf dung cho cac muc dich k h a c n h a u t r o n g Xi nghiep STT L o a i nvtdc svt d u n g hxidng (m^/nam) 1' Nude sinh boat 3120 Nude san xuat da 1000 Nude ve sinh cong nghiep 1348 Nude cho cac cong doan san xuat 25732 Tong 31200 3.2 Q u i t r i n h c o n g n g h e c h e b i e n Cac loai san pham torn, mUc, ca dong lanh deu dUdc che bien theo quy trinh chung nbu d hinh Tuy nhien, theo loai san pham ma cd the bdt di mot boac mot so* cong doan Tren cd sd tbdi gian nghien cdu tai xi nghiep, quy trinh che bien torn thit dong lanh dUdc lUa chon la doi tUdng cho kiem toan vdi t r o n g t a m k i e m t o a n la moi trUdng nUdc bao gom cac noi dung sau: (1) Tinb toan lUdng nUdc thUc te sxi dung; (2) Tinb toan can b§ng nUdc cho qui trinh che bien tom de xac dinh cac khau gay that thoat nUdc; (3) Tinb can b^ng chat thai vkn de xac dinh lUdng chat thai di vao dong thai; (4) Tinb toan chi phi cho viec sii dung nUdc vUdt dinh mvic va dUa cac bien phap n h i m tiet kiem nUdc cho xi nghiep; (5) De xuat giai phap tiet kiem nUdc sii dung, giam thieu lUdng nUdc thai va xii ly nUdc thai d cong doan cd dac tinb nhiem cao 67 Ngu3'en lieu: Tom mUc, ca i Tiep nhan, rda nguyen lieu, — • N u d c thai Nudc da—> bao quan Nudc da—• Nude—• Da_> Xiily + Riia Ian Nudc thai, CTR — • N u d c thai Nudc thai, nhat tap chat Nhat tap chat + Nude—• Da-> Nudc—^ Rua Ian Phan cd hang — • N u d e thai i — • N u d c thai Riia Ian i De rao nUdc, can, xep khuon i Chd cap dong Nudc—• i Nude thai, bao bi thai bd Tach khuon, ma bang, dong tui PE i May kim loai Thiing-> carton Nang lUdng—^ i Bao goi, dong tbung carton i ^ Thiing phe thai Bao quan kho lanh Hinh 1: Quy trinh cong nghe che bien 68 3.3 T i n h t o a n c a n b ^ n g nxidc v a c h a t t h a i r a n Binh mite ni/dc sti dung Nham dap ling cac yeu cau ve ve sinh thUc pham, hien xi nghiep dang tien hanh san xuat theo mot so'tieu chuan kiem soat chat lUdng thuy san nhu GMP (He thong san xuat to't), HACCP (He thong phan tich rui ro va kiem soat gia tri tdi ban) De thUc hien tot cac tieu chuan tren dong tbdi nham giam cbi phi cho san xuat xi nghiep da dUa dinh mute nUdc sii dung cho nguyen lieu torn nhU sau; Tom cac loai: 20 m^/TNL; Dinh miic da sii dung la tan da/TNL Tuy nhien, dinh miic xi nghiep dUa mdi chi dUdc thUc hien mot so' cong doan thUc te lUdng nUde sii dung cua xi nghiep cao hdn dinh miic r^'t nhieu Can bang nitdc qud trinh san xuat tom * Ludng nude sii dung cac cong doan san xuat: Ta so' lieu bang 2, ta thay rang lUdng nUdc dung cac cong doan san xuat la 25.732m2/nam Theo bo phan ki thuat cua xi nghiep ti le sii dung nUdc so sanh vdi dinh mdc de san xu^'t TNL torn, mUc, ca t r o n g thUc te tUdng iing la 2: 3: Tii ti le va can cii vao lUdng n g u y e n lieu t h u mua moi loai nam 2002 c6 tong so' p h a n nUdc sii d u n g la: (302,5 tan tom x 2) + (171,9 tan mUc X 3) + (23,7 tan ca x 3) = 1192,2 (phan) LUdng nUdc dung cho qui trinh che bien tom: Wt5^ = 25732 : 1191,8 x ^ 43,18 (m^) * LUdng nUdc diing de ve sinh nha xudng (nam 2002): LUdng nUdc dung de ve sinh nha xUdng: 1348m3 : 498,3 TNL = 2.7 (mWNL) Vi vay, tong lUdng nUdc sii dung (gom ve smh nha xUdng) cho TNL (tom) la: 43,18 + 2,7 = 45,88 m^ 69 Nhu vay lUdng nUdc sii dung vUdt dinh miic tinh tren T N L doi vdi nguyen heu dau vao la tom rat Idn (gap hdn 2-3 Ian), tUdng iing la: 45,88 - 20 = 25,88 m^/TNL Nhu vay tong lUdng nUdc sd dung vUdt dinh mdc n a m 2002 (W^^^j^) la: WvDM(tdm) = 25,88m3/TNL x 302,5TNL/nam = 8 , m / n a m Can b ^ n g nUde dUdc t i n h t o a n cho tufng cong d o a n , cac k e t q u a dUdc cbi r a d b a n g Bang 3: Lifdng nUdc suf d u n g va nifdc t h a i t r o n g cac cong doan san xuat TT Dau vao Cong d o a n che bien (m^/TNL) Da (Tan/TNL) Nxidc Nvidc t h a i (m^/TNL) Tiep nhan nguyen lieu, riia, bao quan 3,04 0,5 3,54+ Aw Sd che nguyen lieu 33,6 34,6+ Aw Rijta Ian 2, nhat tap chat 1,5 0,25 1,75+Aw Phan cd bang 0,25 0,25± Aw Ru[a Ian 3, de rao, can Xep khuon 0,123 Tach khuon, ma bang, dong PE 1,717 Tong 42,08 2,1 2,l±Aw 1,717+Aw 2,0 43,975±Aw (*)Ghi ehu: A^ - LUdng nLf6c chenh lech that thoat (bay hoi, ng^'m, ) hoac lai tii cong doan trxidc ^WT{*)" ^^^^ Lutdng nUdc chenh lech that thoat (bay hdi, ngam, ) hoac lai tCt cong doan trU6c 70 Trong cac cong doan eiia qui trinh che bien tom chi c6 cong doan xep khuon la nUdc dUdc di vao san pham lai t a t ca cac cong doan khac nUdc va nUde da tan deu theo eac mang thoat nUdc thai ngoai Ngoai qua trinh san xuat mot lUdng nUde bi t h a t thoat bay hdi, tham vao san nha va eac dung eu thiet bi Do d6 qua so lieu tong ket d bang tren thUe te lUdng nudc thai la: Wj^^ = 43,795± AWT(*) (m'VTNL) Dinb mde da sU dung cua xi ngbiep vdi torn la: tan/TNL NhU vay CO the thay lUdng da sii dung cae eong doan la phii hdp vdi dinh mile dat TU cac ket qua tinh toan tren ta c6 the dUa sd can bang nUdc nhu hinh Nguyen nhan dan den sii dung ni/dc vUOt dinh mdc Cac ket qua tinh toan can bang nUdc ket hdp vdi qua trinh khao sat eac dieu kien san xuat xi nghiep nguyen nhan dan den lUdng nUde sii dung vUdt hdn nhieu so vdi dinh mUc la do: - Nudc dUdc sii dung ehUa hdp ly cho cong doan sd che nguyen lieu Trong cong doan torn dUde boe v6, bd dau, rut ruot dUdi vdi nUdc ehay nhe Tuy nhien qua thuc te nhan thay khong phai luc nao cong nhan ciing de tay dUdi voi nUde NhU vay se c6 nln2ng khoang tbdi gian nUdc ehay ma khong dUdc sii dung do se gay lang phi rat nhieu nUdc - Xi nghiep mdi ap dung dinh miic nUdc sii dung mot so eong doan nhu riia nguyen lieu, ban pham, xep khuon Tuy nhien, d moi cong doan doi thuoc vao loai nguyen lieu, miJc saeh ban eiia nguyen lieu, ma lUdng nUdc dinb mdc c6 the thay doi, va rat kho xac dinh lUdng nUdc sii dung viec thay nUdc phu thuoe vao mau nUdc va mUe cam quan cua ngUdi eong nhan - Xi ngbiep ebUa c6 dong ho nUde eho ttfng eong doan san xuat do chUa xac dinh dUdc chinh xac lUdng nUdc sii dung cho tiing eong doan la bao nhieu, cong doan nao vUdt hdn so vdi dinb mdc 71 - Mot so van nUdc moi noi bi hu hong lam nude bi ro that thoat ngoai - Y thUc tiet kiem nUdc eiia cong nhan cbUa cao - Ngoai viee dung 6'ng nhUa mem de ve sinh thiet bi nha xudng, ve sinh cac dung cu san xuat nhU thiing difng nguyen lieu, ro ra, thau chau cung la nguyen nhan lam tang lUdng nUdc sU dung Tom nguyen lieu: 1000kg Tie]D nhan nguyen lieu Rua Ian Bao quan Nude: 3.04mDa: 0.5 tan Da: 0,5 tan ^ V Nudc thai: 3,36± A ^ (m-) S'^i ehe nguyen lieu |Nudc da tan: 1.5+ A\v Nirdc: 33,6m'^ Da: tan Nude thai: 1,5± A^y (m*') Riia lim 2, nhat tap chat [Nudc "dd ta"nro"25±2?u, NUdc: l,5m^ Da: 0,25 tan Phan cd hang Da: 0,25 tan Nudc: — • 2,lm;i+0,123m;! Nudc 0,9mH0.817m'^ Nudc thai 3,04 ± Aw(m-J) Rua Ian 3, de rao, can, xep khuon Nude thai Chd dong, cap dong tach khuon, ma bang, dong PE Nude thai 1,777 ± Aw(m'^) 2,1 ± Awta'O Bao goi carton Bao quan Hinh 2: Sd can b^ng nUdc qua trinh san xuat torn 72 Can bang chat thai ran qud trinh che bien tom * Q u a k e t q u a theo doi cua bo p h a n ky t h u a t ciia xi nghiej) cho thay: - 1000 kg n g u y e n lieu (XL) d a u vao sau ciua sd che khoi ludng BTP t h u dUdc t r u n g binh la 500 kg Khdi ludng phe thai thu dude la 470 kg N h u vay lUdng p h e t h a i r a n di vao dong thai eong doan na>- la: P h e t h a i r a n di vao dung thai - NL - B T P - P h e thai r a n t h u gom = 1000 kg- 500kg - 470 kg = 30 kg 500 kg B T P sau (lua cae cong doan riia p h a n cd b a n g , riia kin de tao den t h a n h p h a m binh cd kbo'i lUdng la 490 kg LUdng phe t h a i r a n t r o n g eac eong doan n a y la: P h e thai r a n di vao - T P = 500 - 490 - k g Ian 2, n h a t t a p chat, (TP) cudi c u n g t r u n g di vao dong thai long dong t h a i long = B T P Tii ket (jua tren ta eo sd can b a n g chat thai r a n nhU sau (hinh 3): Tom nguyen lieu 1000kg Xiily Phe thai ran Ihu gom: 470kg Phe thai r^n di vao dong thai: 30kg BTF: 500kg RUa nhat tap chat phan cd h a n g Phe thai r^n di vao dong thai: 10kg I T h a n h pham 490kg Hinh 3: Sd c a n b a n g c h a t t h a i r a n Tu! sd can b a n g c h a t t h a i r a n ta t h a y tong lUdng phe t h a i di vao dong t h a i t r o n g q u a t r i n h s a n x u a t torn la: 30 + 10 = 40 (kg/TNL) 73 LUdng phe thai di vao nUdc thai va day c u n g chinh la nguyen n h a n lam cho nude thai che bien t h u y san noi c h u n g bi o nhi6m cac chat hUu cd nang Oo e^n phai c6 bien p h a p n h a m h a n ehe tdi da lUdng phe thai Co nhU vay mdi lam giam dvrdc nong cac chat nhiom nude thai T i n h c h i p h i d o v i e c suf d u n g ni^dc viftft d i n h mufc g a y r a Chi phi dude tinh chii yeu t r e n cd sd dien sii d u n g eiia m a y bdm nUdc tUdng Ung v6i tong lUdng nUdc sii d u n g vUdt dinh miie ciia xi nghiep h a n g n a m : 7828.7nr', tUdng dUdng vdi 71 (ngay) sii d u n g Xi ngbiep eo may bdm nUde v6i tong n a n g lUdng tieu t h u la: (1) May hut nudc tiT gicng Ion: 7.5kW/h x 12h/ngay x 71 n g a y / n a m = 6390 kW/nam (2) May bdm Idn; 3.7 kW/h x 4h/ngay x n g a y / n a m = 1051 k W / n a m (3) May bdm nhd: 1.5 kW/h x 8h/ngay x 71 n g a y / n a m = 852 k W / n a m Tong = 8293 (kW/nam) Chi phi cho sii d u n g nUdc vUdt dinh mde t i n h theo gia dien t r u n g binh la 1000 dong/kW NhU vay chi phi n a n g lUdng cho viec bdm nUde diing VUdt dinh mdc la: 8293 x 1000 ^ 8.293.000 (dong) Viec diing nUdc vttdt qua so vdi dinh miic se l a m t a n g ehi p h i s a n xuat eiia xi nghiep len 8.293.000 dong O day e h u n g toi mdi chi t i n b den chi phi cho viee bdm nUdc T r o n g thUe te, viee sii d u n g vUdt d i n h mUc se lam t a n g t h e m eac ehi phi k h a c eho xi n g h i e p nbU ebi phi eho hao mon may bdm bao dUdng may bdm, chi phi xii ly nUdc t h a i , chi phi cho eae van moi trUdng p h a t sinh nUde t h a i k b o n g d a p ling dUoe cac yeu cau ve nUdc thai ebo phep theo TCVN 5945 - 1995 3.5 D e x u a t c a c phiicfng a n g i a m t h i e u v a x i ly n U d c t h a i Qua ket qua p h a n tich nUdc thai trUdc va sau xii ly ciia xi n g h i e p t h a y rang, he tbo'ng xii ly nUde t h a i h i e n tai ehUa hieu q u a va k h o n g 74 dap ijfng dudc cac tieu c h u i n chat lUdng nUdc thai hien hanh ciia Viet Nam (TCVN 5945- 1995 Loai B, va TCVN 6984 - 2001 (Q< 50m3/s, Fi) Nudc thai sau xii ly cua xi nghiep van vUdt tieu chuan cho phep do'i vdi cac cbi tieu BOD, COD, pho't tong so', dau md dong thUc vat va coliform Do can c6 bien phap cai tao lai be thong xii ly nUdc t h a i de nUdc thai dau dap itng dUde eac tieu chuan hien h a n h (xem bang 4) Bang Ket qua phan tich ni/dc thai tai x n g h i e p F.37 T h o n g so Dtfn vi TT TCVN TCVN Ni^dc Nifdc 5945-1945 6984-2001 thai thai sau (Loai B) (Q