Cơ hội cho các hệ thống xử lý nước thải ngành công nghiệp chế biến nông sản thực phẩm

Dien dan<br /> <br /> <br /> <br /> <br /> cho cac he thdng xuT ly niTcfc thai<br /> <br /> Ctf hdi nganh cong nghiep che bien<br /> nong san thuc pham<br /> <br /> <br /> <br /> PHI/ONG PHAP XLT LY<br /> NUdc thai do cdng nghiep che bien ndng san thUc<br /> pham thai ra thudng cd dac tfnh chung la d nhiim hUu cd<br /> rat cao, nUdc thai thUdng cd mau xam den va khi thai vao<br /> cac thuy vUc ddn nhan, thUdng gay d nhiem nghiem trpng<br /> do sU phan huy ciia cac chift hUu cd dien ra rift nhanh. Tuy<br /> thudc vao tUng nganh nghe che bien ma thanh phan ciia<br /> nudc thai cd nhUng dac diem rieng. NUdc thai ciia cdng<br /> nghiep san xuift bia va nUdc thai ciia cdng nghiep mfa<br /> dudng, che bien tinh bpt san... thUdng cd ham lUiing chat<br /> hUu cd va chat ran Id lUng rift cao. Them vao dd la cac hoa<br /> chift sU dung trong qua trinh san xuift nhU CaC03, CaS04,<br /> H3PO4, xiit, soda... Nhu'ng chift nay ciing vdi cac chift hu'u<br /> cd trong nUdc thai cd kha nang de dpa nghiem trpng tdi<br /> thuy vUc ddn nhan neu khdng dUdc xU ly triet de.<br /> TU trUdc nam 2000, viec xU ly nUdc thai nganh cdng<br /> nghiep che bien ndng san, thUc pham d nhieu ndi tren the<br /> gidi chil yeu ap dung qua trinh xU ly hieu khf dien hinh la<br /> he thdng be biin hoat tinh AEROTEN. He thdng nay tuy cd<br /> mdt sd Uu diem, nhUng cd nhUng tdn tai la ddi hdi dien<br /> tfch mat bang va chi phf dau tU xay dUng Idn, chi phf trong<br /> viin hanh he thdng cung rat cao do phai sU dung nhieu<br /> nang lUiing. Gia thanh xU ly se giam xudng cdn mdt nifa<br /> khi ap dung qua trinh xU ly ky khf, vf du nhU thiet bj UASB.<br /> TS. NGUYEN PHU C^ Trong 2 thap ky vUa qua, he thdng xU ly ky khf kieu UASB<br /> quy md Idn da dUdc xay dUng, lap dat va dUa vao viin<br /> Pho Vu trudng Vu KHCN<br /> hanh de xU ly nUdc thai dd thj va cdng nghiep che bien<br /> ndng san, thUc pham d nhUng viing cd khf hau ifm nhU An<br /> Dp, Brazil, Colombia, tham chf ca d viing cd khf hau lanh<br /> Tuy thudc vad tUng nganh nghe nhu Ha Lan va Bac My vdi qui md ciia he thdng xU ly tdi<br /> che bien ma thanh phan cua hang chuc ngan m^ nUdc thai trong mdt ngay dem. NhiJng<br /> nUdc thai cd nhUng dac diem thiet bj UASB nay thUdng dUdc van hanh vdi thdi gian IUu<br /> rieng. NhUng chat nay cung vdi nUdc tU 6-8 gid va dat hieu qua xU ly BOD khoang 80%,<br /> cac chat hUu cd trdng nUdc thai gia trj COD cua ddng thai sau xU ly nam trong khoang<br /> 100-200 mg/l va TSS dat khoang 30-70 mg/l.<br /> cd kha nang de dpa nghiem trpng<br /> Viec sU dung thiet bj UASB de xU ly nUdc thai ciia<br /> tdi thuy vUc ddn nhan, neu khdng nganh cdng nghiep che bien ndng san thUc pham cung<br /> dupc xU ly triet de. gap phai mdt sd trd ngai nhift djnh. Od la, ngoai viec chi<br /> thfch htip vdi nhu'ng ndi cd khi hau ifm ap va ddi hdi thdi<br /> gian khdi ddng dai, thi hien tUdng nhUng chift ran Id lUng<br /> trong nUdc chUa xU ly cd xu hUdng tfch tu trong thiet bi<br /> <br /> <br /> <br /> 12| KHOA HOC & C 6 N G NGHE • (S6 1 - 4/2010<br />  Dien dan [!9iT!!!iS<br /> <br /> <br /> <br /> <br /> xU ly, dan den lam giam the tfch hUu fch ciia hat biin (cdng dau tu xay dUng he thdng xU ly nUdc thai theo md hinh ket<br /> ddng vi sinh vat), lam cho hieu qua loai bd COD thap. Them htip ky khf va hieu khi thay vi xU ly hieu khf ddn thuan kieu<br /> vao dd, hau het lUting COD cd kha nang a xit hda nhanh AEROTEN nhu tai Td'ng cdng ty Bia - RUtiu - NUdc giai khat<br /> deu bj chuyen hda trong he thdng cdng dan, gay anh hudng Ha Ndi (Cdng ty me; Cdng ty CP Bia Thanh Hoa), Td'ng cdng<br /> tdi sU sinh trUdng ciia vi sinh vat chuyen hda a xit ben trong ty Bia - RUdu - NUdc giai khat Sai Gdn (Nha may Bia Cii Chi,<br /> thiet bj xU ly. Mat khac, chift lUting ciia nUdc sau xU ly se Nha may Bia Sai Gdn - Ha Ndi...), Cdng ty CP Ddng Xanh<br /> kem di ddi vdi he thdng xU ly tai viing cd nhiet dp thifp hdn Quang Nam...<br /> 18°C. NhUng han che tren day ciing vdi kha nang thap kem<br /> ciia he thdng xU ly ky khi trong viec loai bd cac chiit dinh CO HOI GIAM C H I P H I<br /> du'dng nhu N, P, S khien cho viec can phai ap dung he thdng Nham tan dung triet de ngudn tai nguyen, giam bdt<br /> xU ly thU cap bang qua trinh hieu khi la can thiet, de nang ganh nang chi phf cho cd sd trong dau tU va qua trinh van<br /> cao chift IUdng ddng thai sau xU ly. Vdi sU phUc tap nay, cac hanh he thd'ng xU ly nUdc thai, hau het cac cd sd neu tren<br /> nha mdi trUdng trUdc day cd xu hUdng khdng mudn ap trong thdi gian qua da lap dat he thdng thu hdi khf methan<br /> dung trUc tiep he thdng xU ly ky khf. sinh ra trong qua trinh xU ly ky khf de diing lam nhien lieu<br /> Thanh tUu dac biet cd y nghTa trong cdng nghe xU ly phuc vu nhu cau ciia ban than doanh nghiep.<br /> nUdc thai vdi nhUng viing cd khi hau ifm ap de xU ly nUdc Viec tan dung nguon nang lUting nay, ngoai viec gdp<br /> thai la viec ap dung ket hdp xU ly ky khf va xU ly thU cifp ph'an trUc tiep vao giam chi phi nang lUting ciia doanh<br /> bang qua trinh hieu khf hoac cac ao hd sinh hpc. He thdng nghiep, cdn cd y nghia trong viec giam phat thai khi nha<br /> xU ly ket hdp nay cd the dUtic xay dUng va van hanh vdi chi kinh. Chinh vi le dd, ddi vdi nhUng dU an cd he thdng thu<br /> phf thifp hdn nhieu so vdi viec ap dung rieng re qua trinh xU hdi methan lam nhien lieu cd the dUtic hUdng cac quyen<br /> ly ky khf hoac hieu khf thdng thUdng. He thdng xU ly ket theo cd che phat trien sach CDM, dd la doanh nghiep cd<br /> hdp ky khf ndi tiep hieu khf cd nhieu Uu viet hdn so vdi he quy'en nhUting, ban quy'en phat thai CO2 theo sd lUting ma<br /> thdng xU ly hieu khf thdng thUdng, ctJ the la IUdng biin dU doanh nghiep da dUtic cac cd quan chUc nang xac djnh va<br /> tao ra trong qua trinh xU ly nhd, tieu hao ft nang lUting va cdng nhan. Ngudn tai chfnh nay se la ngudn dang ke giiip<br /> chu trinh xU ly ngan. Mdt Uu diem ndi bat khac cua he thdng cho doanh nghiep bii dap chi phf van hanh va bao dUdng<br /> ket hdp la kha nang phan hiiy hoan toan bang con dudng toan bd he thdng xU ly nUdc thai va nhU vay, ganh nang ve<br /> sinh hpc mdt sd hdp chat tdng hdp nhift dinh, ma nhUng tai chfnh de xU ly nUdc thai da dUtic giam bdt dang ke, tao<br /> chift nay khdng the phan hiiy d he thdng xU ly rieng biet ky dieu kien thuan ldi de doanh nghiep thUc hien viec xU ly<br /> khf hoac hieu khf. He thdng ket htip ndi tiep xU ly ky khf, chift thai theo cac quy djnh v'e bao ve mdi trUdng.<br /> hieu khf nay dang dddc phat trien vdi nhi'eu dang khac Tuy nhien, viec dang ky de cac dU an dUtic hUdng quyen<br /> nhau. Mdt dang ket hdp khac bao gdm thiet bj dem biin theo cd che CDM phai tuan thu theo cac quy djnh ciia Bd Tai<br /> ngUdc ddng phan doan (Upflow Staged Sludge Blanket- nguyen va Mdi trUdng va cac cd quan cd lien quan tU bUdc<br /> USSB) va thiet bj mang sinh hgc hieu khf hoac he thdng ndi xay dUng dU an, lUa chpn cdng nghe cho den xay dUng va<br /> tiep thiet bi UASB va be biin hoat tinh. He thdng UASB va van hanh. Do han che trong viec nam bat quy trinh dang ky<br /> thiet bi biin hoat tinh dat hieu qua xU ly cao nhat vdi nUdc du an theo cd che CDM va cac thii tuc khi trien khai ma cac<br /> sau xU ly dat B0D7 = 10 mg/l, tham chf d di'eu kien bat Itii doanh nghiep rift liing tiing trong viec tham gia chUdng<br /> ve nhiet dp (13"C). So sanh vdi he thdng xU ly hieu khi ddn trinh, khien sd dU an dUtic cdng nhan va hudng cac quyen<br /> thi vdn dau tU (tfnh theo the tfch thiet bj) va chi phi van ldi theo cd che phat trien sach d nUdc ta khdng nhieu. Do<br /> hanh re hdn tU 2,5 den 3 lan. dd trong thdi gian tdi, cac doanh nghiep khi tien hanh d'au<br /> Tiep thu nhUng tien bp mdi trong ITnh vUc xU ly nUdc tu he thdng xU ly nUdc thai, can phai tim hieu, sU dung cac<br /> thai nganh cdng nghiep che bien ndng san thUc pham, nha tu vifn chuyen nghiep de cd the tan dung dUdc cd hdi<br /> nhieu cd sd san xuat ciia nUdc ta trong thdi gian qua da trong viec giam ganh nang chi phf cho xU ly nUdc thai.*:*<br /> <br /> <br /> <br /> (S6 1 - 4/2010) 1 KHOA HOC & CONG NGHE 113<br />