Kêt quả nghiên cứu thiết kế chế tạo thiết bị lọc nước sử dụng vật

KHOA HOC CONG NGHE
K E T P U A IMGHIEIV CIJU T H I E T K E CHE T A O
T H I E T B I LOC IVIUQC S U DUIMG V A T L I E U IVAIMO
X U L Y IMUQC IMHiilVI A5EIM
Ha Luong Thuan'
TOMTAT
Su 6 nhiim thach tin trong nude ngam da d miic cao vl phd biin d viing chau tho song Hdng va
mot vli noi khIc. Diiu tra so bg d mot sd dia phuong cho thay, him lugng asen trong nude nglm
d nhiiu noi vugt qui tieu chuan cho phep ddi vdi nude an udng va sinh hoat. Di tai da nghien ciiu
sir dung vat lieu loe nano eiia Vien ban lam KH Tu nhien Lien bang Nga, thiit ke, chi tao thief bi
loe nude hi nhiim asen tren eo sd phue vu cap nude sinh boat d Viet Nam. Thiit hi Igc cd ele
c6ng suit: 60-80 1/h, 200-240 1/h, 300-350 1/h, 450-500 1/h da duge chi tao va da tiin hinh kiim
nghiem trong phdng thi nghiem va ngoai hien trudng. Kit qua kiim nghiem ngoli hien trudng da
cho kit qua tdt, sd mlu cd ndng do asen dat blng va dudi 0,01 mg/1 II 95,45% (tdng sd mlu nude
II22), thiet bi van hinh an toan, tdt. Kit qua loe se tdt hon khi kit hgp vdi ele bien phIp khIe.
Tir khda: Asen, nhiim asen, vat lieu nano, thiet bi loe, nuoc sinh hoat, kiem nghiem.
LDATVAniOE
Ngudn nude, dae biet II nude nglm, a nhiiu noi
tren thi gidi bi nhiim asen. O Bang La Det, theo
thdng ke ciia UNICEF, nhiiu viing cd tdi 90-100% ele
giing khoan hi d nhiim asen. Cd nhung vting, ngudn
nude nglm phue vu ddi sdng sinh hoat ngudi dan cd
him lugng asen cao gap hing nghin lln tieu chuan
cho phep (theo WHO tieu chuan nay II < 0,01 mg/1).
Cac qudc gia dang phIt trien khIe d chau A vl chau
Phi ciing dang trong tinh trang ngudn nude nglm hi
6 nhiim asen o miic bio dong.
Theo ude tinh ciia td chiic UNICEF, tai Viet
Nam hien nay, sd ngudi ed nguy eo mac benh do tiip
xiie vdi thach tin (asen) len tdi 10 trieu ngudi. Su 6
nhiim thach tin trong nude nglm da d miie cao va
phd biin d viing chau tho s6ng Hdng. CIc diiu tra so
bd d mdt sd dia phuong cho thay, ham lugng asen
trong nude ngam d nhiiu noi vugt qua tieu chuan
cho phep ddi vdi nude an udng va sinh hoat, cao nhat
II ele tinh, thInh: HI Nam, HI Ngi, Hung Yen, Ha
Tay(eu), Phii Thg... Ham lugng asen d mot sd diem
cao gap nhiiu lln miic cho phep nhu: Quynh Loi (HI
Npi) gap 30 lln. Lam Thao (Phii Thg) gap 50-60 lan,
Ly Nhan, Binh Lue (Ha Nam) gip 50 lln. Cae bien
phap dang duge Ip dung hien nay nhu loe be eat,
dung giln mua khi hieu qua trong viec loai bd thach
tin. Tuy nhien, d cac ho gia dinh, khong phai liie nao
PGS.TS Vien Nuac, Tuoi tieu va Moi truong
74
nhiing bien phIp nly ciing dugc Ip dung hieu qua,
do him lugng thach tin qui cao. Ben canh dd, di xir
ly nude bi 6 nhiim asen, nhiiu bien phap e6ng nghe
da duge Ip dung, trong dd ele phuong phIp chii yiu
dugc Ip dung rgng rai bao gdm: Keo tu, kit tiia - ling
hay cong keo tu - kit tiia - lang; oxi hda; sii dung Inh
sing mat trdi hay oxi hda quang hda; hap phu; trao
ddi ion; Ige qua ldp vat lieu Igc, Igc mang; phuong
phIp sinh hgc va cay trdng.... Nhiing nam gin day
ele e6ng nghe xu ly nud'c tren co sd c6ng nghe nano
hien dang duge nghien eiiu vl ung dung d nhiiu
nude tren the gidi. Vat lieu nano II sin phim cila
e6ng nghe tien tien dang duge ung dung rgng rai.
Th6ng qua viec hgp tic vdi Vien HIn lam KH Tu
nhien Lien bang Nga, di tii da thiit ki, chi tao thiet
bi Igc nude hi nhiim asen tren eo sd ling dung vat
lieu nano phue vu cap nude sinh hoat df Viet Nam.
II. UniG DUNG THIET Bj LOG NUDC SD DUNG VAT UEU NANO
TRONG THUC TE
1. Thiit bi Igc nude nhiim asen sir dung vat lieu
Igc nano
Thiit hi dugc nghien ciiu vl chi tao tren eo sd
kit qua nghien eiiu cua di tii "Nghien eiiu thiit ki,
che tao thiit hi sir dung vat lieu nano de xii ly nude
ed nhiim asen phue vu d p nude sinh boat nong
thon." Thiit hi gdm:
- Vat lieu nano do Vien bin llm Khoa hgc Tu
nhien Lien bang Nga cung cap. Vat lieu nly da dugc
kiem nghiem va cho phep su dung vao linh vuc Igc
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 6 - THANG 6/2010
KHOA HOC CONG NGHE
nude trong chuong trinh nude sach eua Cong hda
Lien bang Nga.
- Loi Igc: Loi Igc llm bang nhua, ben trong chiia
vat lieu Igc nano, loi Igc cd hai diu diu ed ranh de
dua nude vIo va ra, dau nude vIo d phia dudi, nude ra
d phia tren, nude sau Igc trin qua phIn khoang trdng
giiia loi va than mIy rdi di ra ngoli. Ttiy theo chit
lugng nude eiia timg viing, ngoli loi Ige asen cdn cd
them 1,2 hoac 3 loi Ige th6 (cap Ige).
- Vd thiit bi: bao gdm than mIy vl di, than mIy
ed hai bg phan than tren va than dudi ed ren di lip
khdp vdi nhau, than mIy ed chiic nang bio ve loi ben
trong vl giir cho nude luu thong phia ben trong than
sudt qui trinh mIy van hanh, di II bg phan do' cho
toln bg thief hi giii vung d vi tri thing nhu hinh ve.
Vd ed thi lam blng nhua hoac inox. Ngoli ra cdn ed
ele phu kien khIe.
- Nguyen ly boat dong ciia thiit bi Igc ting dung
vat lieu nano: Nude nhiim asen duge dua vao dng
dan nude vao, sau dd nude dugc day vao phia trong
loi loe nano theo hudng di tir dudi len, phia ben tren
eua loi Ipc nano cd nhiiu khe hd di ddng nude sau
xii ly chay trIn qua khdng gian giiia than may vl loi
nano. Nude sach chay vIo Id thu nude vl theo vdi ra
de dua vIo su dung. Hoat dong eiia thiit hi kha don
gian va tien sir dung di cd the lap dat vIo ele vi tri
khIe nhau.
'rhan may
t V o i ra
iofina chcn
Vo
Hinh 1. Thiet bi Igc nude nhiim asen su dung vat Ueu
Igc nano
Thiit hi Ige ed ele e6ng suit: 60-80 1/h, 200-240
1/h, 300-350 1/h, 450-500 1/h. Kha nang Igc nude bi
nhiim asen eua thiit hi (duge kiem tra trong phdng
thi nghiem) dugc thi hien d bang 1.
Bang 1: Kit qua Igc nude hi nhiim asen cua
thiit bi loe
Nong dp asen
(mg/1)
Kiem tra lan 1
Kem tra lan 2
Kiem tra \in 3
Dau vao
Dau ra
0,148
0,148
0,28
0.002
0,008
0,01
TCNBoYte
(1329/2002)
0,01
0,01
0,01
Kit qua tren cho thay vat lieu Ige dat hieu qua
rat cao (TCN 1329/2002) khi ndng do asen trong
nude diu vao khoang tii 0,1 - 0,3 mg/1 (vugt ttr 10-30
lln tieu chuan).
2. Lua chgn dia diem ling dung c6ng nghe
HI Ngi (khu vuc HI Tay eu), II nhiing noi ngudn
nude nglm bi 6 nhiim asen kha nang, trong dd nang
nhlt II cac huyen Thanh Oai, Ung Hda, Qudc Oai.
Tren co sd khao sit thuc ti da ehgn dia bin xa Cao
Duong, huyen Thanh Oai II noi lap dat thiet bi Igc
nude su dung vat lieu nano di kiim tra kha nang Ige
asen ciia thiit bi d thuc ti.
Xa Cao Duong each HI Ngi gin 35 km vi phia
Tay Ble vdi dan sd gin 10.000 ngudi chia thanh 6
cum dan cu. Da sd ele hd gia dinh su dung ngudn
nude mua cho muc dich an, udng. Nude sinh boat
ehung vIn su dung nude giing khoan qua Igc cit. Vi
miia kho cd nhiiu ho phai diing nude giing khoan de
phue vu sinh hoat. CIc trudng mlu gilo, mim non
trong xa thiiu nude mua cho muc dich an, udng cua
tre em vl gilo vien. 0 nhiim asen da dugc cac co
quan ehuyen mdn, y ti kiim tra, lay mlu phIn tich va
th6ng bio, dinh diu. Sd mlu nude giing khoan xet
nghiem ed ndng do asen > 0,05 mg/1 chiim tdi 74,3%
, trong dd cd ele mlu nude tai ele trudng mim non.
Tuy nhien, tren dia ban vIn chua ed cong nghe nIo
xu ly asen hieu qua, phIn Idn xu ly so bd bang be loe
elf.
Thiit bi Ige duge lap dat tai 3 noi: Hd gia dinh
(nhl anh Nguyin Dinh Van), quy md cum hd, trudng
hgc dat tai Trudng Mim non Thi Nguyen va Trudng
Mim non trung tam xa Cao Duong.
Hien trang ngudn nude eiia ho gia dinh gdm bi
nude mua 4 m^ diing cho muc dich an, udng va
ngudn nude giing khoan sau khi qua bi Ige so bg
dugc su dung cho muc dich sinh boat ehung trong
gia dinh: tam, giat, riia, ve sinh,...vlo cudi miia kh6
thudng xuyen thieu nude mua sir dung cho muc dich
an, udng. Ndng do 6 nhiim asen trong nude giing
khoan tai gia dinh II 0,25 mg/1 va sau be loe cat la
0,08 mg/1.
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 6 - THANG 6/2010
75
KHOA HOC CONG NGHE
Bg phan cap nude cho Trudng Mim non trung
tam xa Cao Duong gdm: Giing khoan dan dung vdi
mIy bom 0,75 kw, be loe 1 m^* vl bi chiia 2 m^ tren
san thuong khu trudng hgc. Hien tai, trudng mam
non su dung ngudn nude giing khoan qua Ige elf de
phue vu muc dich sinh boat ehung: tam giat, chuan
bi dd an, rua tay, ve sinh...Ndng do 6 nhiim asen
trong nude nglm la 0,15 - 0,23 mg/1 va sau bi loe elt
la 0,09 mg/1.
Bg phan elp nuoc cho Trudng Mam non Thi
Nguyen - xa Cao Duong, gdm: giing khoan vdi bom
0,75 kw, bi Igc elt 1 m^ vl be ehiia 2 m^ Nude sau
Ige se duge bom tir bi chiia len bdn inox Son HI tren
san thugng khu trudng hgc de cap nude cho muc
dich rua tay, ve sinh cho tre. Ndng do 6 nhiim asen
trong nude nglm II 0,2 mg/1 vl sau bi Ige eat II 0,08.
Trudng ed mot bi nglm chiia nude mua khoing 8 m^
nhung da hi hdng.
Lo! Nana b e Aif ii
Thtctbiloc uinwyV !y Z^i-n
h5 zid dlnii
Hinh 2: Thiet bi Igc nude hi nhiim asen cong
suat 60-801/h
Thiit bi Ige nude ho gia dinh vdi 3 cap Igc:
d p Ige th6: Vat lieu polypropylen vdi kich thude
Igc: 5 - 1 0 pm (micro met), elp Igc tinh: Vat Ueu than
boat tinh dang hat 1-2 mm, cap loe tinh xii ly asen:
blng vat lieu Igc ling dung cdng nghe nano.
b. He thdng xulyasen quy mo cum ho gia dinh,
trudng hoc, cong suit 300 lit/h
+ Cae thong sd ky thuat dugc trinh bIy trong
bang 3.
3. Lap dat thiet bi
So dd lap dat thiit hi tai cac diim thuc nghiem
nhu hinh 1 sau:
Nguon eap
nude
L5i ihiin li<-a! tinh
H? thong
be Ipe tho
hp gia dinh
Bang 3: Cac thdng sd ky thuat ciia thiet bi cong suat
300 lit/h
STT
He thong
thiet bi ioc
1
1
2
3
Nuac ra dat
tieu chuan
4
Hinh 1: So dd lap dat thiet bi
a. He thdng xulyasen quy mo ho gia dinh, cong
suat 60-80 lit A
CIc th6ng sd ky thuat dugc trinh bay trong bang
2.
1/h
5
6
7
Thong sd
Kich thuoc
(dai - rpng - cao), cm
Cap loi lpc
Ap luc met cot nuoc (m)
Trpng lugng thiet bj (kho)
(kg)
Toe dp lpc toi da Oit/gio)
Loe asen dat (mg/1)
Lupng nuoc lpc tdi da Qit)
Kich thuoc, quy mo
76-34-80
3 cap
4-6
18.5
300
<0,01
40.000
Thiit bi Igc nuoc bi nhiim asen, cdng suat 300
dat tai hai trudng mam non (hinh 3).
Bang 2: Cac thdng sd ky thuat ciia thiit bi cdng
suat60-801it/h
L0i than ho^t Unh
STT
1
2
3
4
5
6
7
Thong so
Kich thuoc
(dai-rpng-cao),cm
Cap loi Ipc
Ap luc met cot nuoc (m)
Trpng lupng thiet bi (kho)
(kg)
Toe dp Ipc toi da Oit/gio)
Lpc asen dat (mg/1)
Lupng nuoc lpc toi da Oit)
Kich thuoc, quy mo
55-17-45
3 cap
3-5
5,5
80
<0,01
10.000
Thiit bi Ige nude bi nhiim asen, cdng xuat 60-80
1/h dat tai ho gia dinh (hinh 2).
76
LSi Nano
Igc Asen
B$ Igc don chiec
T h i ^ til Ioc nii6c xiyiy Asen
tnjr6ng m ^ non
Hinh 3: TTiiit bi Igc nude bi nhiim asen cong suat
3001/h
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 6 - THANG 6/2010
KHOA HOC CONG NGHE
- Cap Ige tho: Vat lieu polypropylen vdi kich
thude Ioc: 5-10 pm (micro met).
Bang 4: Kit qua phan tich va hieu qua xii ly asen dgt 1
- d p Igc tinh: Vat lieu than boat tinh dang hat 12 mm.
STT
Ten va ky hieu mau
1
Hp gia dinh
Truoc thiet bi
Sau thi^t bi
Truong MN
Cao Duong
Truoc thiet bi
Sau thiet bi
- d p loe tinh xu ly asen: Vat lieu Igc nano.
4. Kiim nghiem thiit hi
Noi dung kiem nghiem thiit hi gdm: Kha nang
Ioc asen ciia thiit bj d thuc te; theo doi tinh trang
hoat dong (rd ri, hd van, tic ..) vl Itm lugng..; vl ele
van d i phIt sinh khIc. Thdi gian kiim nghiem thiit
bi trong 1 thang, mdi dgt quan trie vl lay mlu nude
each nhau 7 ngly. Mlu nude dugc giii di phan tich
tai Trung tam Phan tich M6i trudng- Vien Khoa hgc
Hda e6ng nghe (ky hieu A) vl Phdng Phan tich M6i
trudng - Trung tam qudc gia v i Nude sach vl Ve sinh
n6ng thdn (ky hieu B).
i
a. Quy trinh lay miu nude
Lly mlu nude trudc vl sau thiet bi Igc d thuc dia
theo cIc tieu chuan sau: TCVN 5992:1995 (ISO 56672: 1991): Chit lugng nude - Lly mlu. Hudng din ky
thuat lay mlu; TCVN 5993:1995 (ISO 5667-3: 1985):
Chit lugng nude - Lay mlu. Hudng din bao quan vl
xir ly mlu; TCVN 6663-5:2009 - Chat lugng nude Lay mlu. Mlu nude trudc thiet bi (tnrde khi xu ly)
lay tai van tdng elp nude vIo thiit hi: mlu sau thiet
bi (sau khi dugc xii ly) lly sau khi nude chay qua
thief bi duge khoang 15 phiit. Nude duge chiia trong
chai nhua PE dung tich 350 - 500 ml ed nip kin. Khi
lay mlu ed dai dien don vi su dung thiit hi chimg
kiin vl ky vIo bien ban lly mlu. Mlu trudc thiit hi
ky hieu Ml; mlu sau thiit bi ky hieu M2.
b. Phuong phap phan tich
Phuong phIp phan tich xae dinh ele thong sd
chit lugng nude thuc hien theo ele tieu chuan hien
hanh eiia Viet Nam: TCVN 6626-2000 (ISO 119691996) - Xle dinh asen. Phuong phIp do hap thu
nguyen tir (ky thuat hydros).
Mlu nude sau khi Ige duge so sinh vdi
QCVN01:2009/BYT quy dinh miic gidi ban cae chi
tieu chat lugng ddi vdi nude diing d i an udng (ggi tit
11 nude an udng).
2
Nong dp asen
(mg/1)
Ml
M2
0,09
<0,005
Ml
M2
0,1
<0,005
Bang 5: Kit qua phan tich va hieu qua xix ly asen dgt 2
STT
Ten va ky hieu mSu
1
Hp gia dinh
Truoc thiet bi
Sau thi&t bi
Truong MN
Cao Duong
Trudc thiet bi
Sau thiet bi
Truong MN Thi Nguyen
Truoc thiet bi
Sau thiet bi
2
3
Ky hieu
mSu
Ndng dp asen
(mg/1)
A
B
Ml
M2
0,25
0,005
0,230
0,005
Ml
M2
0,15
0,01
0,145
0,002
Ml
M2
0,2
<0,005
Bang 6: Kit qua phan tich va lieu qua xu ly asenI dgt 3
TT
Ten va ky hieu miu
1
Hp gia dinh
Truac thiet bi
Sau thiet bi
Trucmg MN Cao Duong
Truoc thiet bi
Sau thiet bi
Truong MN Thi Nguyen
Truoc thiet bi
Sau thiet bi
2
3
ky hieu
mau
Nong dp asen
(mg/1)
A
B
Ml
M2
0,32
<0,005
0,27
0,005
Ml
M2
0,3
<0,005
0,265
<0,005
Ml
M2
0,03
<0,005
0,025
<0,001
Bang 7: Kit qua phan tich va hieu qua xii ly asen dgt 4
TT
1
2
c. Ket qua xd ly asen ciia thiet bi
Kit qui xii ly asen cua thiit hi kiem nghiem tai
hien tru-dng duge trinh bIy trong cIc blng 4, 5 vl 6
dudi day.
Ky hieu
mau
3
Nong dp asen
(mg/1)
Ten va ky hieu m&u
Truong MN Cao Duong
Truoc thiet bi
Sau thiet bi
Truong MN Thi Nguyen
Truoc thiet bi
Sau thiet bi
Hp gia dinh
Trudc thiet bi
Sau thiet bi
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 6 - THANG 6/2010
Ml
M2
0,06
0,005
Ml
M2
0,09
<0,005
Ml
M2
0,09
0,02
77
KHOA HOC CONG NGHE
d. Danh gia kiem nghiem
trudng
thiet bi ngoai hien
- Qua k i t qua 4 dot lly mlu theo doi chi tieu asen
cac mlu trudc thiit hi diu vugt QCVN01:2009/BYT
tir 3 lln din 30 lln (mlu M13, M15), sau khi loe qua
thiit bi sd mlu ed ndng do asen dudi 0,01 mg/1 II
95,45% (theo QCVN 01: 2009/BYT). Rieng 1 mlu
nude lay lln thii tu eua hd gia dinh sau khi xet
nghiem cho k i t qua 0,03 mg/1 gIp 30 lln quy chuan
cho phep, chiim 4,55%.
- Cd su sai khIe giiia hai noi phan tich nhung k i t
qua sai khIe kh6ng nhiiu, nen chat lugng Ige bao
dim yeu cau.
- Thiit hi van hanh theo diing thiit k i ban diu
dua ra, khong hi bi tie, d i van h i n h quan ly.
- Thiit hi dat tai ho gia dinh din lln thii tu kh6ng
dat tieu chuan theo quy dinh II do su dung q u i cong
suit (Tinh theo tdng lugng nude ehly qua thiit hi)
din tdi hieu suit Igc kem.
III. KET LUAN
Hieu qua Igc eua thiit bi ddi vol ngudn nude bi
nhiim asen trong pham vi ndng do asen gap 30 lln
tieu chuan cho phep. Ddi vdi viing bi nhiim asen cao,
de keo dii tudi thg eiia loi Igc nano vl tang hieu q u i
Ige cIn kit hgp vdi ele e6ng nghe khac nhu loe qua
elt vl cac chat hap thu khIe. Khi dd kha nang Igc
nude ed nhiim asen vdi ndng do cao hon se tang.
Qua kit qua nghien eiiu va thii nghiem thiit hi
tai hien trudng cho thay su dung vat lieu nano trong
thiit hi Igc nude hi nhiim asen mang tinh kha thi rat
cao. Chat lugng Ige dam bao tieu chuan quy dinh
QCVN 01: 2009/BYr. Viec san xult thiit hi phue vu
nhu elu loe nude eiia nhan dan viing hi nhiim asen
II holn toln k h i thi.
Tren eo sd k i t q u i da ed eIn tiip tuc holn thien,
xay dung quy trinh san xuat, tiin tdi xay dung dai tra
thiit hi loe nude bi nhiim asen.
TAIUEUTHAMKHAO
1. Center for Biological and Environmental
Nanoteehnology (2006). Annual Report to the
National Science Foundation (NSF). Year 2006.
2. D i tai RDN04-01. Hoan thien cong nghe xii ly
nuoc de ap dung cho mot sd trudng hgp nguon nude
bi nhiim arsenic, ngudn nude nhiim amoni voi ham
luong Idn. Cong ty Nude vl Moi trudng Viet Nam
thuc hien nam 2005-2006; chii nhiem KS. Dinh Viet
Dudng.
3. HI Luong Thuin v l nnk (2009). Bio clo d i tii
"Nghien ciiu thiit k i , c h i tao thiit bi su dung vat
lieu nano d i xtr ly nude ed nhiim asen phue vu cap
nude sinh boat n6ng th6n.
4. Ngo Ngoe Cat and Ngo Viet Dung (2004).
Groundwater contamination by arsenic in Ha Nam
province and experiment of treatment technologies
in household scale. Proceedings of the second
International Symposium on Southeast Asian Water
Environment.
5. Tran Hieu Nhue (2000). Some arsenic
treatment technologies in the groundwater serving
domestic water supply in urban and rural areas.
International Conference on Arsenic contamination,
Hanoi.
RESEARCH RESULT OF DESIGNING AND PRODUCTTHE ARSENIC FILTER EQUIPMENT USING
NANO MATERIAL FOR ARSENIC TREATMENT
Ha Luong Thuan
Summary
Groundwater contamination by arsenic at high degree in Red river delta and other provinces. Arsenic
content of groundwater are higher than standard of drinking water as QCVN 01: 2009/BYr. Arsenic filter
equipment using nano material was designed and produced for drinking water purpose. Arsenic filter
equipment with deference capacity as 60-80 1/h, 200-240 1/h, 300-350 1/b, and 450-500 1/h was tested in
laboratory and in the field. The experiment of the equipment is in good result with arsenic content is 0.01
mg/1, it take 95.45% of total 22 water sample and good operation and management. The equipment will
operate bester when combination with other measures.
Keywords: Arsenic, contamination by arsenic, nano material arsenic Slter equipment, drinking water,
experiment
Ngudi phan bien: PGS.TS. Hoang Thai Dai
78
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 6 - THANG 6/2010