Nghiên cứu xử lý nước thải chứa kim loại nặng (cr, ni) bằng mùn cưa kết hợp với hệ thống đất ngập nước nhân tạo

L I CAM OAN Tên là: Ch Th Thùy Linh Mã s h c viên: 138440301020 L p: 21KHMT21 Chuyên ngành: Khoa h c Môi tr ng Mã s : 60520320 Khóa h c: 21 đ t Tôi xin cam đoan quy n lu n v n đ c th c hi n d is h ng d n c a TS Bùi Th Kim Anh PGS.TS Bùi Qu c L p v i đ tài nghiên c u lu n v n “Nghiên c u x lý n c th i ch a kim lo i n ng (Cr, Ni) b ng mùn c a k t h p v i h th ng đ t ng p n c nhân t o” ây đ tài nghiên c u m i, không trùng l p v i đ tài lu n v n tr c đây, s chép c a b t kì lu n v n N i dung c a lu n v nđ c th hi n theo quy đ nh, ngu n tài li u, t li u nghiên c u s d ng lu n v n đ u đ c trích d n ngu n N u x y v n đ v i nôi dung lu n v n này, xin ch u hoàn toàn trách nhi m theo quy đ nh./ NG I VI T CAM OAN L IC M N L i đ u tiên c a lu n v n xin chân thành c m n TS Bùi Th Kim Anh, phòng Th y sinh h c Môi tr ng, Vi n Công ngh Môi tr PGS.TS Bùi Qu c L p, b môn Khoa h c Môi tr L i Th y Cô t n tình h ng, tr ng ng i h c Th y ng d n giúp đ su t trình th c hi n lu n v n Tôi c ng xin chân thành c m n anh ch phòng Th y sinh h c Môi tr ng, Vi n Công ngh Môi tr ng, nhi t tình ch b o t o m i u ki n cho su t trình làm lu n v n Dù có nhi u c g ng, song n ng l c h n ch nên lu n v n c a ch c ch n không th tránh kh i thi u sót Tôi mong nh n đ ki n đóng góp c a Th y Cô b n đ lu n v n đ c hoàn ch nh h n Tôi xin chân thành c m n! Hà N i, ngày 01 tháng 06 n m 2015 H c viên cao h c Ch Th Thùy Linh cý M CL C M U .2 DANH M C HÌNH DANH M C B NG CH NG 1: T NG QUAN CÁC V N NGHIÊN C U 1.1 T ng quan v kim lo i n ng 1.1.1 Ngu n g c phát sinh kim lo i n ng nh h tr ng c a đ i v i môi ng 1.1.2 Các ph ng pháp x lý ô nhi m kim lo i n ng 11 1.2 Khái quát v s d ng mùn c a x lý n c th i ch a kim lo i n ng 17 1.2.1 Quá trình th y phân mùn c a 18 1.2.2 Tình hình s d ng h p ch t h u c khác đ làm ngu n Cacbon ch t kh x lý n c th i ch a KLN giàu sunfat .20 1.2.3 S d ng mùn c a nh ch t h p ph sinh h c đ x lý n 1.3 Tình hình nghiên c u n c 21 c 22 1.3.1 S d ng mùn c a đ x lý KLN .22 1.3.2 S d ng công ngh đ t ng p n 1.4 Tình hình nghiên c u c nhân t o (Constructed wetland) 24 Vi t Nam .25 1.4.1 S d ng mùn c a đ x lý KLN 25 1.4.2 Tình hình s d ng công ngh đ t ng p n CH NG 2: V T LI U VÀ PH c nhân t o đ x lý KLN 26 NG PHÁP NGHIÊN C U 28 2.1 V t li u nghiên c u 28 2.1.1 Mùn c a 28 2.1.2 Th c v t th y sinh: Cây S y 28 2.1.3 á, cát, s i… 29 2.2 a m nghiên c u 29 2.3 Ph ng pháp nghiên c u 29 2.3.1 Ph ng pháp u tra, kh o sát .29 2.3.2 Nghiên c u k th a tài li u liên quan .30 2.3.3 Ph ng pháp phân tích đánh giá phòng thí nghi m 30 2.3.4 S d ng ph ng pháp b trí thí nghi m logic đ đánh giá nh h ng c a y u t liên quan đ n hi u qu x lý kim lo i n ng 31 2.3.5 Thi t k h modul x lý xác đ nh thông s công ngh c a quy trình 33 CH NG 3: K T QU VÀ TH O LU N 40 3.1 Hàm l ng KLN n c th i t i làng ngh c kim khí Phùng Xá, Th ch Th t, Hà N i 40 3.2 K t qu nghiên c u trình th y phân c a mùn c a PTN 41 3.2.1 S bi n đ ng c a COD môi tr 3.2.2 Hàm l ng r ng 38 u etylic, methanol, axetic axit theo th i gian thí nghi m 39 3.3 Kh n ng x lý ô nhi m Cr, Ni n c c a mùn c a quy mô PTN 40 3.3.1 Thí nghi m so sánh hi u qu x lý c a đá vôi, mùn c a h n h p đá vôi mùn c a .40 3.3.2 ánh giá kh n ng x lý h n h p Cr, Ni c a đá vôi mùn c a theo th i gian thí nghi m .45 3.3.3 Xác đ nh li u l ng mùn c a h x lý 50 3.4 Quy trình công ngh x lý n th c v t th y sinh c th i ch a Cr, Ni b ng mùn c a ph i h p v i qui mô pilot 53 3.4.1 Nhu c u oxi hóa h c (COD – Chemical Oxygen Demand) 53 3.4.2 Hi u qu lo i b SO 2- 55 3.4.3 Hi u qu lo i b Cr6+ 57 3.4.4 Hi u qu x lý Cr3+ 59 3.4.5 Hi u qu lo i b Ni2+ 61 K T LU N .63 TÀI LI U THAM KH O 69 DANH M C HÌNH Hình 1.1: S đ dây chuy n công ngh m n Hình 1.2: Thành ph n c a g 17 Hình1.3: Công th c hóa h c c a xelulô 18 Hình 1.4: Tác d ng c a t ng enzym xenlulô 18 Hình 1.5: Quá trình th y phân xenlulô 19 Hình 1.6 N 24 c th i ADM tr c x lý (n m 1995) sau x lý Hình 2.1: Cây s y (Phragmites australis) 28 Hình 2.2: Hình nh nguyên li u đ u vào 31 Hình 2.3: S đ h th ng k t h p đá vôi mùn c a 34 Hình 3.1: Hình nh mùn c a tr 38 c sau tháng th y phân Hình 3.2: th th hi n s bi n đ ng COD trình phân h y xenlulô thí nghi m 39 Hình 3.4: Hi u su t x lý Cr3+ gian thí nghi m n ng đ 20 mg/l (CT1) 35 mg/l (CT2) theo th i 42 Hình 3.5: Hi u su t x lý Ni2+ gian thí nghi m n ng đ 20mg/l (CT1) 35mg/l (CT2) theo th i 43 Hình 3.6: Hi u su t x lý Cr6+,Cr3+, Ni theo n ng đ th i gian thí nghi m t 0.5 đ n 8h 48 Hình 3.7: Hi u su t x lý Cr6+,Cr3+, Ni theo n ng đ th i gian thí nghi m t 10h đ n 72h 49 Hình 3.8: Hi u su t x lý Cr6+ , Cr3+, Ni2+ theo li u l Hình 3.9: Hàm l ng mùn c a ng COD bi n đ ng theo th i gian t i ch ng c a b x lý 51 53 Hình 3.10: Hàm l ng sunfat bi n đ ng theo th i gian c a h th ng x lý Hình 3.11: Hàm l ng Cr6+ bi n đ ng theo th i gian t i ch ng c a b x lý 58 Hình 3.12: Hàm l ng c a Cr3+ bi n đ ng theo th i gian t i ch ng 60 Hình 3.13: Hàm l ng c a Ni2+ bi n đ ng theo th i gian t i ch ng 62 55 DANH M C B NG B ng 1.1 Kh kim lo i n ng b v i bùn ho t tính 13 B ng 3.1 K t qu kh o sát n 36 c th i làng ngh Phùng Xá B ng 3.2 K t qu phân tích s n ph m c a trình trao đ i ch t 40 B ng 3.3 Hi u qu lo i b h n h p Cr, Ni theo th i gian thí nghi m 45 B ng 3.4 Kh n ng lo i b Cr, Ni c a h n h p đá vôi mùn c a theo li u l mùn c a ng 51 M U Tính c p thi t c a đ tài Ô nhi m kim lo i n ng (KLN) đ t n đ i v i nhi u n c th gi i c ng nh c v n đ tr m tr ng Vi t Nam i u thu hút s quan tâm đ c bi t c a nhà khoa h c lo i ô nhi m r t ph c t p, ngày ph bi n ti m n nhi u nguy c đ i v i s s ng c a sinh v t nói chung c a ng i nói riêng T i Vi t Nam, n c th i c a m t s ngành công nghi p nh m n, luy n kim, s n, khai thác ch bi n crôm, thu c da, khai thác m … ch a nhi u kim lo i n ng gây ô nhi m môi tr làng ngh kim c khí ch a hàm l ng c bi t, n ng KLN, sulfat, nitrat, amoni…r t cao C n có kho ng 1450 làng ngh 100% làng ngh đ môi tr l ng Các làng ngh s d ng l ng n c th i c a m t s c c u tra đ u gây ô nhi m ng l n hoá ch t th i môi tr ng kh i c th i không nh có đ đ c h i cao, ch a nhi u kim lo i n ng nh : Fe, Cr, Ni, Zn, CN C th , m i ngày làng ngh c kim khí Phùng Xá, Th ch Th t, Hà N i c tính th i kho ng 5000m3 n hàm l c th i lo i Các lo i n ng Cr, Ni, Pb, Cd, COD, sulfat, nitrate, amoni v Hi n có nhi u ph ng pháp đ ph t TCCP nhi u l n [6] c áp d ng đ x lý n nh hóa h c, hóa lý sinh h c M c dù x lý n c th i có c th i nhi m KLN c th i nhi m KLN b ng ng pháp hóa h c hóa lý (k t t a hóa h c, oxy hóa-kh , trao đ i ion, keo t t o c n, h p ph , x lý n hóa, s d ng màng,…) đ t tiêu chu n môi tr cho phép nh ng ph ng ng pháp đ u có chi phí x lý cao s d ng hóa ch t, v t li u đ t ti n, đ ng th i t o l ng c n l n t k t t a kim lo i hóa ch t t n d gây ô nhi m th c p cho môi tr ng Trong n hàm l n ng KLN cao có h p ch t h u c , ion sulfat, nitrate, amoni,…l n c ph ng pháp hóa lý khó lo i b t p ch t Các ph h c phù h p đ x lý kim lo i ngu n n c a ph c th i c a c s ng pháp đ t cao n ng pháp hoá c th i công nghi p hi u qu c có n ng đ cao c a kim lo i c n x lý Tuy nhiên, th c t v n nh ng t n t i s d ng ph ng pháp ó là, thành ph n ô nhi m c a dòng th i r t ph c t p, t n t i nhi u y u t c n tr , nên hi u qu x lý không tri t đ Do v y, th c t , sau x lý b ng bi n pháp hóa h c l i ph i c n đ n bi n pháp x lý b sung nh m lo i b n t l kim lo i v n d l i n n ng c sau x lý Do n ng đ d c a kim lo i c r t nh nên vi c lo i b n t vô khó kh n Các ph ng pháp hóa h c không tác d ng bi n pháp sinh h c có th mang l i hi u qu S d ng ph ng pháp sinh h c (s d ng th c v t th y sinh, v t li u h p ph sinh h c vi sinh v t đ c hi u) đ x lý ô nhi m KLN có nhi u u m nh d ng d ng, chi phí th p thân thi n v i môi tr nhi u n nh ng Ph c quan tâm nghiên c u ng d ng x lý n Nh t B n, ng pháp đ c th i ô nhi m KLN c, Thái Lan, Trung Qu c, Trong nghiên c u này, mùn c a t trình ch bi n g s đ hóa sinh h c KLN n c s d ng v i c hai m c đích h p ph chuy n c th i Chính v y, em l a ch n đ tài “Nghiên c u x lý n c th i ch a kim lo i n ng (Cr, Ni) b ng mùn c a k t h p v i h th ng đ t ng p n đ nghiên c u lu n v n th c s c a mình, m t đ i t c nhân t o” ng nghiên c u r t Vi t Nam th gi i Có th k t h p mùn c a v i h th ng đ t ng p m i n c c nhân t o đ làm t ng hi u qu x lý kim lo i n ng có n c th i M c đích c a đ tài - ánh giá hi n tr ng ô nhi m Cr, Ni, n c th i c a làng ngh c kim khí Phùng Xá, Th ch Th t, Hà N i - Nghiên c u quy trình công ngh x lý n c th i ch a Cr, Ni b ng mùn c a ph i h p v i th c v t th y sinh Các ti p c n ph - Ph ng pháp nghiên c u ng pháp u tra kh o sát: Th c hi n vi c u tra, kh o sát ngu n th i gây ô nhi m Cr, Ni, c a làng ngh c kim khí Phùng Xá, Th ch Th t, Hà N i - Ph ng pháp t ng h p k th a: Nghiên c u k th a tài li u liên quan đ n mùn c a th c v t dùng đ x lý ô nhi m KLN - Ph ng pháp phân tích đánh giá s li u: ánh giá hàm l ph ng pháp quang ph h p th nguyên t đo quang Phân tích đánh giá m t ng KLN b ng s ch tiêu COD, H S, m t s ch t h u c hòa tan n - ph ng pháp phân tích thông d ng hi n hành Ph ng pháp th c nghi m khoa h c: S d ng ph logic đ đánh giá nh h lo i n ng Các ph c theo ng pháp b trí thí nghi m ng c a y u t liên quan đ n hi u qu x lý kim ng pháp xác đ nh m t s thông s công ngh c a quy trình (t c đ dòng ch y, th i gian l u, hi u su t x lý, thông s thi t k b x lý ) - Ph ng pháp l y ý ki n chuyên gia: xin ý ki n đóng góp t th y cô, nh ng ng i có liên quan hi u bi t v l nh v c nghiên c u K t qu d ki n đ t đ - c ánh giá v hi n tr ng ô nhi m Cr, Ni n c th i t i làng ngh c kim khí Phùng Xá, Th ch Th t, Hà N i - Báo cáo phân tích k t qu nghiên c u v trình th y phân c a mùn c a phòng thí nghi m qua t ng ngu n vi sinh v t s d ng - ánh giá hàm l ng Cr, Ni mùn c a ban đ u lên hi u qu x lý ô nhi m quy mô phòng thí nghi m - Xây d ng đ c quy trình công ngh x lý n c th i ch a Cr, Ni b ng mùn c a ph i h p v i th c v t th y sinh ánh giá hi u qu x lý KLN c a quy trình CH 1.1 NG 1: T NG QUAN CÁC V N NGHIÊN C U T ng quan v kim lo i n ng 1.1.1 Ngu n g c phát sinh kim lo i n ng nh h tr ng ng c a đ i v i môi a Ngu n g c phát sinh kim lo i n ng Kim lo i n ng môi tr ng đ c t o t hai ngu n ch y u ngu n t nhiên (các ho t đ ng c a núi l a, l ng đ ng t khí quy n, s phong hóa c a đá m khoáng v t,…) ngu n nhân t o (ho t đ ng nông nghi p, công nghi p, khai khoáng, giao thông…) Con ng lo i n ng môi tr i nguyên nhân ch y u làm t ng hàm l ng trình phát th i n c th i đ c h i không x lý ho c x lý không đ t yêu c u M t s n i ô nhi m KLN th v cn ng kim ng g p l u c g n khu công nghi p, làng ngh khu v c khai thác khoáng s n  Khu công nghi p: Các trình s n xu t công nghi p, trình khai khoáng, trình tinh ch qu ng, kim lo i, s n xu t kim lo i thành ph m ngu n gây ô nhi m kim lo i n ng môi tr đ ng n c Thêm vào đó, h p ch t c a kim lo i n ng c s d ng r ng rãi ngành công nghi p khác nh thu c da, cao su, d t, gi y, luy n kim, m n, c ng ngu n đáng k gây ô nhi m kim lo i n ng • Ngu n phát sinh Crôm: Crôm nói chung đ crôm s n xu t đ c bi t đ n s n ph m m crôm H u h t, qu ng c s d ng s n xu t thép không r Tuy nhiên, crôm kim lo i ch t không đ c h i, ch h p ch t c a crôm d đ c tính Trong môi tr ng n Trong đó, Cr6+ xu t hi n n c, crôm ch y u xu t hi n d c th i d Cr O 2- (pH≤ 7) Các h p ch t c a crôm đ n mòn Chúng đ ch n s - i d ng ion Cr3+, Cr6+ m i có i d ng Cr3+, Cr6+ i d ng h p ch t CrO 2- (pH >7) c thêm vào n c làm l nh đ ng n c s d ng trình s n xu t nh : T o màu, nhu m i n c c nhôm trình m kim lo i m n khác Trong ngành công nghi p hóa ch t 65 10 L i Thúy Hi n cs 2003 Nghiên c u x lý h n h p KLN n làng ngh c khí Vân Chàng, Nam c th i nh b ng vi khu n kh sunfua n i t i tài c p Vi n KHCN Vi t Nam ng 11 ình Kim 2004 Kh n ng ng d ng th c v t thu sinh x lý ô nhi m thu v c H i th o Khoa h c “ ng d ng bi n pháp sinh h c n ng cao ch t l ng n ng 12 c h Hà N i” Liên hi p H i KHKT Hà N i, 9-2004 ình Kim cs., 2011 Nghiên c u kh n ng x lý ô nhi m KLN đ t t i vùng khai thác khoáng s n b ng th c v t Báo cáo t ng k t đ tài c p nhà n c KC08.08/06-10 13 Ph m Lu n (1998), C s lý thuy t c a ph h p th nguyên t Ph n I, Ph n II Tr ng pháp phân tích ph phát x ng đ i h c khoa h c - t nhiên, Hà N i 14 Nguy n V n N i nnk, Nghiên c u s d ng mùn c a bi n tính đ x lý n c nhi m d u, 2001 Tuy n t p công trình khoa h c- H i ngh khoa h c k ni m 45 n m thành l p Khoa Hoá h c, Hà N i, tr.130-133 15 Ph m Thành Quân, Nguy n Th ng ng, T ng Thanh Danh, Nghiên c u ng d ng mùn c a v i ph th i t tràm vàng x lý m t s kim lo i n ng n 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Plant Physiol.120: 637-643 30 Lawrence K Wang, Yung-Tse Hung, Nazih K Shammas (2010) Handbook of Advanced Industrial and Hazardous Wastes Treatment CRC Press Taylor & Francis Group pp 231-259 67 31 Preuß, V (2004) "Konkurrenz zwischen Methanogenen und Desulfurikanten bei der biochemischen Entsäuerung von Bergbauwässern bei Verwendung von Methanol als C-und Energiequelle " BTU Cottbuswassertechnik und Siedlungswasserbau56: 57-62 32 The Decomposition of Cellulose From Sylvia, D.M., Fuhrmann, J.J., Hartel, P.G.,& Zuberer, D.A (2005) Principles and Applications of Soil Microbiology 2nd edition, pg 298 33 One Possible Pathway of Lignin Decomposition From Sylvia, D.M., Fuhrmann, J.J., Hartel, P.G.,& Zuberer, D.A (2005) Principles and Applications of Soil Microbiology 2nd edition, pg 304 34 One Possible Pathway of Lignin Decomposition From Sylvia, D.M., Fuhrmann, J.J., Hartel, P.G.,& Zuberer, D.A (2005) Principles and Applications of Soil Microbiology 2nd edition, pg 304 35 Schwenn, J D and W J Cram (1997) Assimilatory reduction of inorganic sulphate.In: Sulphur metabolism in higher plants The Netherlands, Backhuys Publishers, Leiden: 39-58 36 Ola norrman, 1999, “home distillation handbook”, pp 141 37 http://gchudu.blogspot.com/2012/05/chu-trinh-krebs.html 38 http://www.botanyvn.com/cnt.asp?param=news&newsid=1431 39 http://environment.about.com/od/pollution/a/top_10_polluted.htm (Blackmis) 40 http://www.khoahoc.com.vn/print/45557.aspx (Mun cua + da voi) 41.http://nongnghiep.vn/nongnghiepvn/72/45/68/31018/Co-Huong-BaiGiai-phapxu-ly-moi-chat-thai-chan-nuoi.aspx 42.http://nongnghiep.vn/nongnghiepvn/72/45/68/31018/Co-Huong-BaiGiai-phapxu-ly-moi-chat-thai-chan-nuoi.aspx 43 http://thietbiloc.com/tin-nuoc/503-xu-ly-nuoc-thai-bang-cay-say J Viet Env.2014 Vol.6, No.1, pp.47-51 DOI: 10.13141/jve.vol6.no1.pp47-51 Phytoremediation of heavy metal polluted soil and water in Vietnam S d ng th c v t đ x lý ô nhi m kim lo i n ng đ t n c t i Vi t Nam Research article Bui, Thi Kim Anh1*, Dang, Dinh Kim1, Nguyen, Trung Kien1, Nguyen, Ngoc Minh2, Nguyen, Quang Trung1, Nguyen, Hong Chuyen1 and Chu, Thi Thuy Linh Institute of Environmental Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam; VNU University of Science, 334-Nguyen Trai, Hanoi, Viet Nam Phytoremediation has been intensively studied during the past decade due to its cost-effectiveness and environmental harmonies Most of the studies on treatment of heavy metal pollution in soil and water by plant species have been done in developed countries but are limited in Vietnam In this study, we presented some research results of phytoremediation of polluted soils and water with heavy metals that were done by Institute of Environmental Technology for several last years For treatment of heavy metal pollution in the water, some plants have great ability to accumulate heavy metals such as Vetiveria zizanioides, Phragmites australis, Eichhornia crassipes, Pistia stratiotes, Ipomoea aquatica, Nypa fruticans and Enhydra fluctuans The heavy metal uptake into shoots and roots of 33 indigenous plant species in Thai Nguyen province was also determined Two species of the plants investigated, Pteris vittata L and Pityrogramma calomelanos L were As hyperaccumulators, containing more than 0.1% As in their shoots while Eleusine indica, Cynodon dactylon, Cyperus rotundus and Equisetum ramosissimum accumulated very high Pb (0.15-0.65%) and Zn (0.22-1.56%) concentrations in their roots Some experiments to clarify the potential of several plants as good candidates for phytoremediation of polluted soil by heavy metals were carried out in our institute Ph ng pháp s d ng th c v t đ x lý ô nhi m đ c nghiên c u nhi u th p k qua chi phí th p thân thi n v i môi tr ng H u h t nghiên c u v x lý ô nhi m kim lo i n ng đ t n c b ng th c v t đ c th c hi n n c phát tri n nh ng có t i Vi t Nam Trong nghiên c u này, gi i thi u m t s k t qu dùng công ngh th c v t đ x lý ô nhi m kim lo i n ng đ t n c t i Vi n Công ngh môi tr ng nh ng n m g n i v i x lý ô nhi m kim lo i n ng n c, m t s th c v t có kh n ng tích l y t t kim lo i n ng nh Vetiveria zizanioides, Phragmites australis, Eichhornia crassipes, Pistia stratiotes, Ipomoea aquatica, Nypa fruticans Enhydra fluctuans S h p th tích l y kim lo i n ng ph n m t đ t r c a 33 loài th c v t b n đ a t i Thái Nguyên c ng đ c xác đ nh Hai loài th c v t kh o sát Pteris vittata Pityrogramma calomelanos nh ng loài siêu tích l y As, ch a h n 0,1% As ph n m t đ t c a Eleusine indica, Cynodon dactylon, Cyperus rotundus Equisetum ramosissimum tích l y Pb (0,15-0,65%) Zn (0,221,56%) r t cao r M t s thí nghi m đánh giá ti m n ng c a m t s th c v t đ i t ng t t cho x lý ô nhi m kim lo i n ng đ t đ c ti n hành phòng thí nghi m c a Vi n Công ngh môi tr ng Keywords: Phytoremediation, * Corresponding author E-mail: buianh78@yahoo.com heavy metal, 47 pollution, potential plant http://dx.doi.org/10.13141/JVE ISSN 2193-6471 Brassica juncea Dang Thi An et al (2007) identified heavy metal concentrations of some vegetables Tran Kong Tau et al (2005) indicated the accumulation ability of Cd and Zn in Calendula officinalis, Acanthopanax aculeatus Tran Van Tua et al (2008) researched on the tolerance and accumulation of Pb, Cd, Cr, Ni and Zn in some plant species Diep Thi My Hanh et al (2007) investigated the Pb accumulation of Lantana camara In this paper, we present some research results of phytoremediation for polluted soil and water with heavy metals Introduction Pollution of soil and water is now a global problem and attracted attention of many countries due to its harmful effects with many aspects of environment and human life In Viet Nam, heavy metal pollution has been identified in many locations including urban areas as well as rural and mountainous ones For example, in Hanoi, Van Dien industrial zone including Van Dien Batteries factory, Synthetic Paint factory, Van Dien Phosphate Company and also Orion Hanel industrial zone have high risk of lead contamination (Le Hien Thao, 2004) The contamination in traditional villages is also an urgent problem There are about 1450 traditional villages, based on the survey results of 52 typical villages, of which 100% surveyed villages had caused environmental pollution Typically, the village recycling lead from batteries of Chi Dao commune, Van Lam district, Hung Yen province has 25 lead production units Every day, this commune produces 10 tons of lead and generates about ton of toxic dust (Dang Kim Chi et al., 2005) During the production, traditional villages released a large amount of significantly toxic chemicals into the environment via wastewater including many heavy metals such as Fe, Cr, Ni, Zn, and CN Mineral exploiting and processing industry discharge highly toxic substances such as Cd, Pb, Zn, Cu, As (Le Van Thanh et al, 2004) The average As concentration in waste stone samples was of 5000 mg/kg, exceeding the allowable standard of heavy metal in the soilmany times The concentration of other heavy metals in the stone samples were also very high (Cu: 1260 mg/kg; Pb: 105 mg/kg; Cd: 0.5 mg/kg; Se: 17 mg/kg, ) (Tiberon mineral company, 2004) In some communes of Ha Nam province, 94.4% wells water samples had very high As concentration, with was exceeded national technical regulation on drinking water quality (Pham Hung Viet et al., 2004) Materials and Methods 2.1 Plant species There are many methods for treating heavy metal pollution Although physicochemical methods are effective, they are complex, expensive, not environmental friendly and difficult to be applied on a large scale Phytoremediation is cost effective, environmental friendly and most suitable for developing countries (Ghosh et al., 2005) At present, more than 500 plant species of metal and metalloid hyperaccumulators have been reported in literatures (Hemen Sarma, 2011) b c d e f g Phytoremediation of polluted soil and water is soon studied in many countries (Salt DE et al., 1995, Raskin I et al., 1997, E Lombi et al., 2001) However, in Viet Nam, this study has been started only in recent years and its practical application is still limited Le Van Cat et al (2008) researched on NH + and As removal capability from contaminated water by Typha latifolia, Canna and Pennisetum purpureum Le Duc et al (2005) studied on Pb uptake of Ipomoea aquatica, Eichhornia crassipes and * Corresponding author E-mail: buianh78@yahoo.com a h i Figure 1: Plant species used in our experiments – (a) Pityrogramma calomelanos; (b) Pteris vittata; (c) Eleusine indica; (d) Brassica juncea; (e) Pennisetum purpureum; (f) Pistia stratiotes; (g) Eichhornia crassipes; (h) Vetiveria zizanioide; (i) Phragmites australis 48 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 were 1, 3, 5, and 10 mg / l Preparing Cr6+, Cr3+ and Ni2+ sollutions by adding K Cr O , CrCl 6H O and NiSO H 0, respectively After 14 days experiment, the investigated plants were harvested and then washed with tap water to remove dust, rinsed with deionized water, and kept dried for 10 hour to evaluate the plant fresh weight The results showed that the tolerance of these species can be arranged in the following order: Vetiveria zizanioides > Phragmites australis > Eichhornia crassipes > Pistia stratiotes > Ipomoea aquatica > Nypa fruticans > Enhydra fluctuans A treating system of Cr and Ni in contaminated water was established at pilot scale by “root zone” technology Two plant species have a high tolerance to Cr and Ni (Vetiveria zizanioides and Phragmites australis) were selected for further studies in pilot scale (0.5m3.day-1) This system worked continuously in 23 weeks (Inlet wastewater is a mixture of electroplating wastewater contained Cr and Ni and animal husbandry wastewater) This inlet wastewater contained average concentrations of Cr6+, Cr3+, Ni2+, COD, T-N as T-P as follows: 1.9, 3.2, 3.88, 111.4, 42 and mg/l, respectively The plant species collected from contaminated sites and from the green house Some plant species were used for experiments such as Ceratophyllaceae, Eichhornia crassipes, Pistia stratiotes, Phragmites australis, Vetiveria zizanioides, Brassica juncea, Lantana camara, Eleusine indica, Pennisetum purpureum, Pteris vittata and Pityrogramma calomelanos Taxonomy of the plant species were done by Assoc Prof Nguyen Xuan Phuong from the Institute of Ecology and Biological Resources, VAST The wastewater samples collected from electroplating industry and soil samples collected from the mining areas that were polluted by heavy metals served for the experiments 2.2 Heavy metal concentration analysis Digestion of heavy metals was conducted using US EPA 3051 method Concentrations of heavy metal in acid digests were quantified with an atomic absorption spectroscopy (AAS; AA-6800, Shimadzu, Japan) and on inductively coupled plasma-mass spectroscopy (ICP-MS, ELAN 9000, Perkin Elmer, USA) Results and Discussions 3.1 Heavy metal removal from water by plants By experimental studies, we have demonstrated heavy metal uptake and accumulation in some aquatic plant species For example, Eichhornia crassipes was likely to absorb Pb, Cr, Ni, Zn and Fe in industrial waste water, Nasturtium officinale L could remove Cr and Ni from electroplating wastewater Meanwhile, Ceratophyllum demersum L., Salvinia cucullata were likely to reduce Fe, Cu, Pb and Zn in Bay Mau lake, Hanoi Figure 2: Ni2+ removing capacity of Vetiveria zizanioides and Phragmites australis Treatment system consists of 03 cement tanks, each tank can contain 0.5 m3 water with rock in the bottom and sand at the top Control tank has no plant, The tanks growing Vetiveria zizanioides and Phragmites australis have plant density is 10 cm × 15 cm Each tank has 108 plants, fresh weight of each branch is of 60 gram FW After 23 weeks experiment at pilot scale, Ni treatment efficiencies of Vetiveria zizanioides, Phragmites australis and control reached 91.5%, 88.4% and 49.68%, respectively Concentration of Ni2+ in outlet of the control, Vetiveria zizanioides and Phragmites australis were 1.95, 0.33 and 0.45 mg/l, respectively (Fig.2) The evaluation on ability to remove Cr, Ni in water of some plant species has been done The plant species were capable of removing Cr and Ni from contaminated water The experiments on tolerance of plant species were evaluated, plant was washed and grown in clean water before days experimental set-up There were seven treatments sets with five replicates for each Each plastic pot contained liter water medium, with 70 gram fresh weight (FW) plant Cr and Ni concentrations in each pot * Corresponding author E-mail: buianh78@yahoo.com 49 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 A B Figure 3: Cr6+ (A) and Cr3+ (B) removing capacity of Vetiveria zizanioides and Phragmites australis After 23 weeks experiment at pilot scale, Cr6+ treatment efficiencies of Phragmites australis and Vetiveria zizanioides were very high reaching 97.97% and 98.12%, respectively [Fig.3] The Cr6+ concentration in inlet wastewater of treatments was 1.92 mg/L, whereas the Cr6+ concentration in outlet of Vetiveria zizanioides and Phragmites australis tank were 0.053 and 0.047 mg/L respectively The inlet Cr3+ concentration of Vetiveria zizanioides and Phragmites australis tank was 3.218 mg/l, outlet of Vetiveria zizanioides and Phragmites were 0.2 and 0.24 mg/l, respectively The treatment efficiencies by Vetiveria zizanioides and Phragmites australis were 95.91% and 92.6%, respectively The outlet concentrations of Cr6+ and Cr3+ were under the limitation for industrial wastewater according to Vietnam standard (TCVN 5945-2005) 1201.4±147.3 and 4346.8±157.9 mgkg-1, respectively and in roots at 3756.9±145.7, 2194.4±155.7 and 3108.7±213.5 mgkg-1 Zn, respectively Our finding in Thai Nguyen province indicates that, two fern Pteris vittata L and Pityrogramma calomelanos L are suitable for As treatment in the mining soil of Ha Thuong, Dai Tu district, four grasses Eleusine indica, Cynodon dactylon, Cyperus rotundus and Equisetum ramosissimumare the best at keeping Pb, Zn concentrations in their root So we can use these grasses for phytostabilization of Pb and Zn in Tan Long, Dong Hy district 3.2 Heavy metal removal from soil by plants As, Pb and Cd accumulations of Brassica juncea were quite good All heavy metals (Cd, As and Pb) can be accumulated in roots more than in the shoots In trace concentration, the heavy metals can stimulate plant growth but with higher concentrations (Cd> 25 ppm, As> 200 ppm and Pb from 2000 to 3000 ppm) they inhibited the plant from growing When Pb concentration in soil was 3000 ppm, the Pb accumulation in shoots and roots were 202.9 and 2425.9 ppm, respectively While As and Cd concentrations in the soil was 25 ppm, the content in shoots and roots were 185.6 and 228.9 ppm (for As); 185.6 and 228.9 ppm (for Cd), respectively Brassica juncea can be used to remove As, Pb and Cd concentration in contaminated soil but it should be noted that this plant also a popular green vegetable for people Based on the screening results, we carried out some experiment concerning with the potential plants as good candidates for phytoremediation of heavy metal polluted soil 3.2.2 Brassica juncea 3.2.1 Screening potential plants for heavy metal removal A total of 33 different plant species samples were collected from four mining areas in Thai Nguyen province to identify the heavy metal concentrations in their roots and shoots The collected plant species can grow at the mine tailings or in the soils affected by mining waste The results showed that ferns, Pteris vittata L and Pityrogramma calomelanos L were capable of accumulating high arsenic concentrations As concentrations in shoot and root of Pteris vittata L were 5876.5±99.6 and 2642.5±72.3 mgkg-1, respectively; while these figures of Pityrogramma calomelanos L were 2426.3±104.5 and 2256±123.4 mgkg-1 Remarkably, a large amount of As from roots of these ferns was transposed to shoot, facilitating the removal of As from contaminated soil The Zn accumulating ability in some investigated plant species was quite high, e.g Equisetum ramosissimum, Cyperus rotundus and Eleusine indica with Zn accumulated in shoots at 1346.2±130.2, * Corresponding author E-mail: buianh78@yahoo.com 3.2.3 Vetiveria zizanioides In soil contaminated with Pb from 1400.50 to 2530.10 mg / kg, Vetiveria zizanioides still grew well after 90-day treatment Some charateristics of plant growing on Pb contaminated soil such as height, root length, biomass and the Chlorophyll concentration increased more than those 50 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 on control soil (soil without Pb) Pb concentration analysis in soil after this experiment showed that, the Pb extraction effect from the contaminated soil by Vetiveria zizanioides could reach from 87% to 92.6% However, the average Pb accumulation in its shoots and roots were not high being only 24 and 349 ppm, respectively This species also can accumulate As and Cd taken from soil Many our further experiment results showed that feasibility of using Vetiveria zizanioides as phytostabilization agent for Pb, Cd and As in contaminated soils tolerance to Cr and Ni concentrations are Vetiveria zizanioides and Phragmites australis Screening research of 33 plant species in Thai Nguyen province indicated that two ferns Pteris vittata and Pityrogramma calomelanos were suitable for As treatment in the mining soil of Ha Thuong, Dai Tu district Four grasses like Eleusine indica, Cynodon dactylon, Cyperus rotundus and Equisetum ramosissimum were the best in accumulating Pb, Zn in their roots Other investigated plant species like Brassica juncea, Pennisetum purpureum, Vetiveria zizanioides were potential to remediate the soil contaminated with As, Cd, Pb and Zn 3.2.4 Eleusine indica Eleusine indica can be used for remediating the soil contaminated with Pb and Zn Results of the survey showed that this plant can grow in the waste area of lead, zinc processing factory Analyzing Pb and Zn concentration in soil and plants showed that if soil contained 4316.96 ppm Pb, there would have 664.45 and 4638.17 ppm Pb in shoots and roots of the plant, respectively; if soil contained 1000 ppm Zn, there would have 761.6 and 2011.3 ppm in shoots and roots, respectively Eleusine indica could grow well at the concentration of Pb and Zn in soil lower than 5000 and 1000 ppm, respectively Acknowledgments This research was funded by the Vietnam Academy of Science & Technology (VAST) and Vietnam National Foundation for Science & Technology Development (NAFOSTED) References [1] Bui Thi Kim Anh, Dang Dinh Kim, Tran Van Tua, Nguyen Trung Kien, Do Tuan Anh 2011 Phytoremediation potential of indigenous plants from Thai Nguyen province, Vietnam Journal of 3.2.5 Pennisetum purpureum When Pb concentration in the soil was 3600 ppm, Pb accumulated levels in shoot and root of the plant were 164.3 and 1009.1 ppm, respectively When Cd concentration in soil was 31.5 ppm, the Cd accumulated concentrations in shoot and root of the species were 5.7 and 320.1, respectively Some other result showed that, the grass accumulated Pb and Cd mainly in roots and the plant grown in the soil with higher heavy metal concentration could accumulate them higher in their biomass Environmental Biology 32: 257-262 [2] Dang, T A., Chu, T T H., Dao, T C T 2007 Some characteristics of the flora in Pb-, Cd-polluted areas in Tan Long, Dong Hy, Thai Nguyen Proceedings of the 2nd National Scientific Conference on Ecology and Biological Resources, Hanoi 26 October 2007 (Sections of Fauna and Flora of Vietnam & Ecology and Environment): 297301 (in Vietnamese) [3] Diep, T M H., Garnier, Z E 2007 Lantana camara L, - the plant species can accumulate Pb in the polluted soil Science and Technology Development Journal 10(1):35-38 (in Vietnamese) [4] Ghosh, M., Singh, S P 2005 A review on Phytoremediation of heavy metals and utilization of its byproduct Applied Ecology and Environmental Research 3(1): 1-18 [5] Hemen, S 2011 Metal Hyperaccumulation in plants: A review focusing on phytoremediation technology J Environ.Sci Technol (2): 118-138 [6] Le, D 2005 Cu, Mn and Mo concentration in some main kind of soils in the south of Vietnam Soil Science Journal 10:193-196 (in Vietnamese) [7] Le, V C., Tran, M P., Le, V L 2008 Simultaneous removal of ammonium and arsenic from ground water by phytofiltration Intern.Sci Conference on “Chemistry for development and intergration, Sept.12-14/2008 Hanoi, Vietnam Proceedings: 679-688 (in Vietnamese) 3.2.6 Pteris vittata and Pityrogramma calomelanos Two ferns Pteris vittata and Pityrogramma calomelanos can grow in the mining soil containing 15,146 ppm As Although they are As hyperaccumulators, the plants still have ability to accumulate Cd, Pb and Zn Pteris vittata and Pityrogramma calomelanos can tolerate 5000 and 4000 ppm Pb; 1200 and 300 ppm Cd, respectively The highest level of As accumulation in Pteris vittata and Pityrogramma calomelanos are 6042 and 4034 ppm (in the fronds); 3756 and 2256 (in the roots), respectively From to months after growing there is appropriate time for harvesting biomass plants if applied in practical processing Conclution Base on the evaluate Cr and Ni tolerance of seven potential plant species, two plant species having a highest * Corresponding author E-mail: buianh78@yahoo.com 51 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 [8] Le, V T 2004 Mining exploitation and impact to the environment Proceeding of mining technical science conference, the sixteenth Cua Lo, 7/2004 (in Vietnamese) [9] Nguyen, T C., Tran, V T., Dang, D K., Do, T, A., Le, T T 2008 The study of Pb accumulation in polluted soil by Vetiver grass (Vetiveria zizanioides) Science and Technical Journal 46(6A): 26-26 (in Vietnamese) [10] Raskin, I., Smith, R D., Salt, D E 1997 Phytoremediation of metals: Using plants to remove pollutants from the environment, Curr Opin Biotechnol, 8(2): 221-226 [11] Salt D.E., Blaylock M., Kumar P.B.A.N., Dushenkov V., Ensley B.D., Chet I and Raskin I 1995 Phytoremediation: A novel strategy for the removal of toxic metals from envrionmental using plants Biotechnology, Vol 13: 468-474 [12] Tiberon mineral Ltd, 2004 Environmental impact assessment report of Nui Phao project, Dai Tu, Thai Nguyen (in Vietnamese) [13] Tran, C T., Dang, T A., Dao, T K H 2005 Some first results on Phytoremediation Soil Science Journal 23: 156-158 (in Vietnamese) [14] Tran, V T., Nguyen, D T., Do, T A., Nguyen, T K., Tran, N N 2008 Treatment of Ni and Cr contained wastewater by root zone method Journal of Science and technology 46(6A): 40-45 (in Vietnamese) [15] US EPA 3051 Method (1994) Microwave-assisted acid digestion of sediments, sludges, soils and oils (pp 1–14) Technical Report, Washington, District of Columbia [16] TCVN 5945-2005 Discharge standards for industrial waste water (in Vietnamese) [17] Le Hien Thao.2004 Seminar on "Current status of heavy metal pollution in Vietnam", Institute of Environment and Natural Resources, VNU HCM, pages (in Vietnamese) [18] Dang Dinh Kim 2010 Study on phytoremediation of heavy metal - contaminated soils in mining areas National project KC08.04/06-10, (in Vietnamese) [19] Dang Kim Chi, Nguyen Ngoc Lan, Tran Le Minh 2005 Vietnam craft village and vnvironment, publishing by scientific and engineering, 391 pages * Corresponding author E-mail: buianh78@yahoo.com 52 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 DANH M C T VI T T T AMD Acid Mine Drainage CNM Công nghi p m n COD Chemical Oxygen Demand CT Công th c CW Constructed wetland C i ch ng KH&KT Khoa h c k thu t KLN Kim lo i n ng QCVN Quy chu n cho phép TCCP Tiêu chu n cho phép TCVN Tiêu chu n Vi t Nam TN Thí nghi m VSV Vi sinh v t PH L C Hình Hình nh mùn c a tr c sau đ c b sung n Hình Hình nh m u sau 30 ngày đ t thí nghi m c Hình i chi u m u mùn c a ban đ u m u mùn c a sau ngâm 73 ngày Hình Hình nh mùn c a tr c sau tháng th y phân Hình M t s nghiên c u phòng thí nghi m Hình Thí nghi m x lý Ni, Cr3+ n ng đ 50-150mg/l phòng thí nghi m Hình Thí nghi m x lý Cr6+ v t li u khác nhau, đá, mùn c a h n h p đá vôi, mùn c a Hình H th ng x lý n c th i ch a KLN tr i thí nghi m Hình Mô hình h th ng x lý n Hình 10 H th ng x lý n c th i ch a KLN tr i thí nghi m c th i ch a KLN tr i thí nghi m