Tgp chi Khoa hge Tru&ng Dai hge Cdn Tha Phdn A Khoa hgc Tg nhiin Cdng nghi vd Moi truong 25 (2013) 44 51 Tap chf Khoa hpc Dai hpc Can Thcf website sj ctu edu vn K H u a ^ DANH GIA DAM TRONG HE T H 6 N[.]
Tgp chi Khoa hge Tru&ng Dai hge Cdn Tha Phdn A: Khoa hgc Tg nhiin Cdng nghi vd Moi truong: 25 (201 Tap chf Khoa hpc - Dai hpc Can Thcf KHua^ website: sj ctu edu DANH GIA DAM TRONG HE T H N G XU* LY NlTOfC THAI AO N U l CA TRA THAM CANH Lam Thj My Nhien', Nguyen Hdng Khoa', Hans Bix" va Ngd Thuy Diem Trang' Bg mon Khoa hgc Mdi trudng Khoa Mdi trudng vd Tai nguyen Thien nhien, Trudng Dgi hgc Can Tha ^Bg mdn Sinh hgc, Khoa Khoa hgc, Dgi hgc Aarhus - Dan Mgch Thdng tin chung: Ngay nhdn: 08/10/2012 Ngdy chdp nhgn: 25/03/2013 Title: Evaluation of nitrogen in waste water treatment system of intensive catfish culture Tit khda: Cd Tra, ddt nggp nuac kien tgo, dgm, h4 so chuyin hod thirc dn chdt lugng nude Keywords: Pangasianodon hypophthalmus, constructed wetlands, nitrogen, FCR, water quality ABSTRACT The objectives in this work were to investigate the real time concentration of nitrogen in constricted wetlands with subsurface horizontal and vertical flow in treatment of close-recirculated intensive catfish (Pangasianodon hypophthalmus) culture Typha orientalis were planted in the systems, and the system of controls were unplanted The inlet water (water fiom the fish tank) and outlet water of treatment systems was collected during 15 weeks to monitor the concentration ofNOrN NO3-N, NH^-N, and TKN over time The results showed that concentrations of nitrogenous compounds were lower in the planted subsurface horizontal wetlands as compared lo the others In addition NO3-N and NOrN levels were increased over time in the vertical flow systems that might affect the growth offish Remarkably, this research was the close-recirculated system, thus can reduce pollution discharge and increase water use efficient that contribute to reduce environmental pollution TOM TAT Miic tieu ciia nghien cuu ndy Id khdo sdt dien Men dam he thdng ddt ngap nude thiel ki dong chdy ngdm ngang va ngdm dgc viic xu ly nude be nuoi cd Tra (Pangasianodon hypophthalmus) thdm canh tudn hodn kin Thuc vdt dugc trdng he thong Id Bon bon (Typha orientalis), vd hi thong ddi chung khdng cdy Nude ddu vdo (hay nude tir bi cd) vd nirdc ddu cua he thdng x«- ly duac thu 15 luan de theo doi dien biin nong NO2-N, NO3-N, NHr-N, vd TKN Nhin chung nong dg dgm nude ciia hi ihong chdy ngdm ngang (DNN NN) cd trdng cdy diu thdp han hi thdng cdn lgi Ngodi ra, he ihong chdy ngdm diing co ndng dd NOj-N vd NOj-N khd cao vd lang ddn theo thai gian, cd the dnh hudng den sinh tnrdng ciia cd Dieu dgc bi^l a nghien cuu ndy Id he thdng ludn hodn kin nen hgn che dugc viec xd nude thdi ngodi mdi trudng vd tang hiiu qud sir dung nude gdp phdn gidm nhiim moi trudng GlOfI THIEU Trong nh&ng nam gdn ddy, cd Tra, Basa la nhiing lodi thuy san chu Iuc duge nudi khd phd biln d khu vuc ddng bang sdng Cim Long (DBSCL) Thuc te da cho thdy nudi ca iheo hinh thuc thdm canh da cd tac ddng rdt idn den mdi irudng thiic an du thua, chdt thai dang phdn vd chdt bdi tiet bi lich tu lai nude va Tgp chi Khoa hgc Trudng Dai hoc Cdn Tha Phdn A Khoa hgc Tu nhiin, Cong nghi vd Mdi tru&ng: 25 (2013): 44-31 ' nghien cdu nhieu ve dien biln cdc dang d£im cdc loai hinh DNN khac Han n&a, theo Vymazal (2007) mdi loai hinh DNN kh&: cd uu vd nhugc diem rieng vl co chl lo^j bd dinh dudng, dac biel la co chl loai bd diim Do dd, nghidn ciiu ndy dugc thuc hien nhSm tim hieu ve dien bien ndng cac dang dam tren hai loai hinh DNN chay ngdm theo phuang ngang va phuang thdng diing theo thdi gian nen day Theo Ducmg Cdng Chinh va Ddng An Thuy (2008) dl sdn xudi lan cd cdn din 1,6 tdn thiic dn Cac nghien ciiu da ghi nhan vdi dien lich ao nudi 5.600 ha, sdn lugng ca udc linh dat 1,5 trieu ldn thi lugng chdt thdi mdi Irudng khodng I trieu lan dd cd 900 ngdn tan chat hiiu ea, 29 ngan tdn N vd 9,5 ngan tan P (tinh tren vdt chdt khd), khoang 250 - 300 trieu m^ nude thai va - Irieu ldn biin thai (Truong Qude Phu, 2007) Chat thai ao ca d dang vat chdt hihi ca, vdi chdi dang hat va vat chat la Iiing (Truong Qude Phu, 2008) Dudi hoat dgng ciia vi sinh vat vd cac qua trinh phan huy, chdt thdi hiiu co ehuyin thdnh cac dang vd CO nhu dam amoni, nitrate, photphal dd kich thi'ch su phat trien eua tdo dan din hien tugng nd hoa Irong ao Them vao dd, cac dpc td phat sinh tii qud trinh phdn huy chat thdi uong nudi va su tan I^i ciia tao lam cho mdi trudng nudi nhanh chdng hi suy ihodi, cdc doi lugng nudi dl bi stress vd chit mdc benh, thilu oxi hay tdng ddc tfnh ciia cac chdt chuyin hoa Trong thuc te Iugng chdt thai hau hit dugc bom true tiep sdng hay kenh rach cac hd nudi chua cd phuang an xii ly Tren the gidi, da cd mpt so nghien cdu ve xii ly chdt thai lii ao nudi ca tra dong thdi tan dung dinh dudng vdi nhieu mue dich He thdng \\i Iy bdng ddt ngap nude (DNN) kit hgp vdi nudi trdng thiiy san luin hoan dd dugc nghien eiiu d DBSCL vdi kit qua kha thi xii ly dam (Trang, 2009; Le Minh Long, 2011) Tuy nhien, tdc gia chua PHUONG PHAP NGHIEN CUU 2.1 Bo tri thi nghiem Bdn h$ thdng DNN chay ngam theo phuang ngang (NN) va bdn he thdng DNN chdy ngam Iheo phuang dgc (ND) da dugc thilt kl vd vSn hanh tren thang bdi Le Minh Long (2011) \i Nguyen Thi Thao NguySn (2011) Tuy nhiSn, ed mdt sd chinh sua he thong dl gidm bdt nhung han che gap phdi thi nghiem cu nhu: hoc ddu vao be ngdm ngang dugc da (0IO-2Omm) chilu cao ngang vdi mat chat nln (20cm) (h^n che hien tugng lao nd hoa d hoc ddu vao), va bd tri Iai mdi he Ihdng xii ly nude thai gdm mdt be cd dilu phdi vao hai be DNN cung loai hinh (Hinh 1) cd trdng cay va nghi$m Ihiic khdng trdng cdy dugc xem la ddi chiing (de xdc dinh ro khd nang xd ly cua moi loai hinh DNN) Mdi he thdng xu ly dugc bd trf lan lap lai dl xu ly nude thai bl nudi ca Tra thdm canh ludn hoan kin 2.2 Thilt ke he thong xu-ly Mdi hi thong xii ly bao gdm: (1) B I cd Tra Hinh l:S(rdobotr{ he thong chay ngam ngang c6 cdy (A), ngam ngang khfing trdng cay (B), ng^m d9c c6 trdng cdy (C),vang^nidQC khong trdng cdy (D) (Ghi chu: x Id \i iri thu mdu) A& DNN KN da DNN KN CO CO caj cay "*V ^_ k ^L DNK NN kh6ng cfly A DNN NN khong cay 1- Tgp ehi Khoa hgc Trudng Dgi hgc Cdn Tho Phdn A: Khoa hgc Tu nhien Cong nghe va Moi Iru&ng: 25 (2013): 44-51 3.840 mL/phiit, he thdng chay ngdm dgc (dugc cai dat 50 phut nghi, 200 giay bam), Idc nude tiir b l cd ia 22.400 mL/phiil Toe nude duge dilu chinh bdng cae van de ddm bao dat 200% luu lugng nude b l cd dugc xu ly vd tuan hodn dem (Trang, 2009) (the lich nude nudi m'): mat nudi Id 110 con/m^ trgng lugng ea ban ddu trung binh 1,6 kg (eho cd an % trgng lugng cd ban ddu bang thiic an vien ndi 25% N (2 ldn/ngay), sau cho an dua theo nhu cdu an ciia ca); (2) hai be DNN (tuong iing vdi I ldn lap lai ciia moi loai hinh DNN); va (3) b l ihu gom cd gdn may bom chim va phao ndi d l bom nude ludn hoan lai be ca (Hinh 1), 2.4 Thu mau va phan tich chat lirgng nude Mdu nude dugc thu tron^ be cd va vi tri dau cua cdc he thdng cd trdng eay va khdng trdng cdy vdi ldn sudt thu mdu lai Ihdng ddu lien Id m6i tudn/Idn, thang sau vdi ldn sudt tudn/ldn Cac vi iri thu mdu dugc danh dau x Irong hinh I Cdc chi tieu pH, EC, DO va nhiet dugc tai khu Ihi nghiem Cdc ehi tieu cdn lai nhu: NO2-N (dam nitrite), NO3-N (dam nitrate), NH4-N (dam amdn), va TKN (long dam Kjeldahl) dugc phdn tieh theo quy trinh tieu chudn danh gia nude va nude thai {A^HAetal, 1998) Cd hai loai hinh DNN kiln tao dugc nghien cuu: (1) Be DNN chay ngdm ngang (200 cm dai X 70 cm ngang x 30 cm cao): d ddu vao mdi b l se dugc ngan hoc dai khoang 30em vd dugc dd da (010-20 mm) cao bdng vdi mat chdt nen, ldp chdt nln day 20em (khoang 190L) la vd sd (02-5 mm), muc nude ludn giu thdp hon mat chdt nln cm; (2) Bl DNN chay ngdm dgc (dudng kinh 80 cm, cao 70 cm) ed Iugng chdt nln khodng 190 L vd he thong phdn phdi nude duge thilt ke trdn be mat Thuc vat dugc trdng Irong he Ihdng la Bdn bdn {Typha orientalis) 2.3 V^n hanh he thong 2.5 Phan tich va xur ly s6 lieu Tat ea sd lieu chdt lugng nude dugc thu thdp, phdn lich thdng ke, so sanh ket qua trung binh giua nghiem thiic dua vdo phdn mem Excel va phan mem thdng ke Slalgraphics Centurion XV (StatPoint, Inc., USA) Nude thdi tir be ca duge bom tdi hai be DNN ciing cua mdt loai he thdng, nude ddu ciia cdc be dugc tap trung lai d mdt bl thu gom va bom trd lai be cd mgt each tu ddng nhd may bam thd chim k8t noi vdi phao dien (Hinh 1) Cdc he thong hoat dong nhd bg hen gid, ddi vdi he thong NN (duge cai ddt 13 phiit bom, 26 phiit nghi) vdi toe bam la K E T QUA VA THAO LUAN 3.1 Chat lirgng nude trudc xu ly Nhin chung, ndng dg cdc thong sd chdt Iugng Bang 1: Cac chi tiSu ly, hoa cua mrdc be nuoi ca trudc sii ly ciia cdc he thong Nghieir tbli'C Thdng sd D0,05; Bang 2), nhung sau qua eae hS thdng DNN thi cd su thay ddi ve ndng DO nude {p0,05) 3.3 Dien bien nong dg d^m h€ thdng nitrate, thuc vai hdp ihu, va cac ca che ly fada nhu kit tlia, bay hoi NH3, trao ddi ion (Kadlec & K n i ^ t , 1996) Tuy nhien, d he thong NN qua trinh ki ddng vai Iro quan Irong dd Ihi qua trinh hiiu khf bi gidi han viec thieu oxy nen khdng phii hgp cho qua trinh nitrate hda (Brbt, 1990; Vymazal & Kropfelona, 2008; Trang, 2009) Dilu Iy giai cho kit qua eua ndng dd NOi-Nvd NO3-N he thdng NN ludn thdp han he thdng ND (p