

J. Jpn. Soc. Soil Phys.
" 
No. 33, p. 1-2- ,**/







 ! ,*ῌ**ῌ**ῌ**Inﬂuence of Flow Rate on Nitrate Removal in Flow Process
Toshio TABUCHI*, Hisao KURODA**, Akiko IKENOBE** and Mayumi HIRANO*** Former professor of The University of Tokyo** College of Agriculture, Ibaraki University, Chuo -῏,+῏+, Ami-machi, Inashiki-gun,Ibaraki, -**῏*-3- Japan
Abstract
Inﬂuence of ﬂow rate on nitrate removal in the ﬂow process was examined in a paddy ﬁeld plot.
Flow rate was changed for three stages.
in the second stage at *.*1- m d+

In the ﬁrst stage ﬂow rate was controlled at *.*.* m d +,and in the third stage at *.+-0 m d +.

Corresponding to theincrease of ﬂow rate, water ﬂows through a plot rapidly. The retention time is ,0.- hours in theﬁrst stage, +0./ hours in the second stage and 3 hours in the third stage.

With the increase of ﬂow

rate, the nitrate concentrations of outﬂow water gradually increased.

The decrease of nitrateconcentration through the ﬂow process also changed.

Coe$cients of nitrate removal rate (a)changed in a day, but the daily average values (a) in each stage were almost constant.
Key words : Paddy ﬁeld, Coe$cient of nitrate removal rate, Temperature, TOCr*b* v*?

+     

 !"#

a3:b;*89m*?

,   $%&'()*++,- ."/0

1 ."'2345#6789'2:3;< = - +321- +33-- +330- ,**+- - ,***>? @<AB/C< 5D'EFGH."+- cU

."'23*v*WX."E/23<? ."[0j ,/m,  +.. m,  -/ m, [/v* =῏+>? ef

 IJKLMNOPQ/ARS'TU<

1c

=

'b =+/ ml s > - , - . + - +332 a, b>? V/ WXYZ<."[/,**-  2  ,. -* /- Aci+ \]^Z* 5_+`a' - bc

C<? B a  -2- ./- .3 mm +a

cd/efU- A67%&'23< =

U- ."['\m*m*bc

 - ,**/>? gh

3.* bc:3<? Br'¡¢ῌ- ¢῍- ¢῎}~£¤i'ajk- 

5#67lm* no'pq*? Ar+m*?

\] 5_Ds@r*tu+
/v*  q wx89/vy- Ar,0.-- +0./-."[M

¥ 0.,/ m cd/ / ¦e¦\]'YZ- AB§¨©ª'Y«U +* cd/©'z{+3|:}~/v*? @efU<? ¬ I¦ §­®'Y«U- -<  i\bc :*/- A

bccd`ef'23<? ef¯* °±²³ ³! ´-**῏*--+ µ¶·¸¹º¸¹ .0-*῏+*. =§»>** µ¶³ ³! ´-**῏*-3- µ¶·¸¹ºM¼ -῏,+῏+: - 67- ©- TOC

EC, pH, DO,¯° ±²³ T 33 ´ P,**/R74 NO--N, T-N, COD, TOC, TIC, T-P   , 




! /"

() 

#$%&'*+,- . /0!

12 *+ 3()NO--N

456789:;<= ! TOC #E|}sT ῌ  ,*~LMEKODJHI`n`() PQῐ-R T῎HIKn`()-+- 0K  E|}s PER D) CQ>?@ TiO, ABCD)ῐ. D) Z-    Fti  1 k2j .DJFG t+  0D)KT , #-+ 
-++/"-/N FGklnHID)K! T῍

FG t,  t+t+ j! .

# EFGHIDJ K! LM -3N!
LO +1N  PQῐ,R

01 , SD)T῍! UEKOD) VWXEYOD) Z) 2 [ ,1 \] ,. mm^_X`abK() ! / c`()de`()h|}Ej t-t,t,  T῎t,~t-

 t-~t.! T῏ t.~t/_# +

EKfg

0

i(J

)j! /

#klYmOn`()+*N op qK D)K(JE D)K

FG |}Ej

wDJj) .  |}E|}D) KFG t+
 0D t/ #D) E

0FG t+ H J¡l¢D! FGEj) ` i¦D)Y ! FGuv,-`)EDJ 

kw# +

EK/ #-+, 


D) 

E Ti, t p£#¤¥|}sD) Qῐ-  0FG`n

prD! # , `\_ s/  t #c`xy Kz{t+  t, Z

TῌE |}sj T῍FD)

Tῌ ,0 FD)
E



FG



FGkl.§u¨HID`! uv ,0N DDT῍0! +0./ FD) ! ©ª qK«-) ,0 \LO ,,N! LM ,1N! /NqK T῎ 3 F`() ! .
HI¬n`() +/~+2 F­®ῌ+
Fig. +



EKMn! LOE q +*N opkw 01KF E FGHI«- !

Experimental plot.

ῌ,Fig. ,



#

E

HI

Changes of water temperature.

 : $5Vys ¡G

ῌFig. -75

NOUV

Changes of mean water temperature.
COD #$%nfES'

o45*+ ,-῏/" 0. UVIWX\ES'" pq6rstuv]E\ES++ew!
 # COD  +x, mg LQ+ 4\" ;5Vy9pq%zE{6S'()G *+Sῌ.
Fig. .

'$% 'UVIWX\E !*'4

UV

5G I|bcn}\EF

Explanation for water temperature in
ﬂow process.

TOC f_~bG" COD 3 /-ῌ 9: /i\E:
TIC  COD  , Ryn}F ^$%



-,+NO--N nfES'45G" ;I|bc2YS'F
 W()G:^" /45G TOC-, 
T-N 

o: pq/ CO, NO--N ῌ

!῍" ῎*" WG+ew!

#$% &'()*+ ,-῏/. ῍-,- ,1 /0123 0*ῌ 45*+

T-P  *.+ mg LQ+ 549$C

T-P 

" 16789: ;9<=>?

*+ghEb*'FEF6a  * **'" 01@ABCD*EFGῌ"  ῍ 9 T-P 45*'F

H 3 I !JH 0 IK9 + /LMB NO*+P

" ῎oW()*'F K+ ,1 //NO NO--N  ῌ 9 0.2

01A{()EF" J ,2 /mg LQ+" $ , RES+῍9 ++.0 mg

E^():  !EF" ! 

LQ+ " $ . RES+῎9 +-.+ mg

utc9:ma 

LQ+ ()*+ ,T῏+" -῏0. UVIWXF" ;

-,.

YZ#[ZIWX\E94

Cl ῌ" ῍93 -/ mg LQ+ y"  NO--N  T-N 3 3*ῌ

*'F

de+ 01

:S+I T-N fghi\ES'j!k" l*m78'4\ES'F-,,COD, TOC, TIC EC῎9 -* mg LQ+ y" 01A \

5$]E\E^()G
T-N  NO--N _`6aEbc

Cl 

B *'F 5Vy9uvffEF
Fa9:ma EC  Cl _`6aE *'F 0

1A Z" ,/*x-** mS cmQ+ 9*'F--  

RS TUV  33 W B,**/D76

῍ῌ/Fig. /



L

Changes of water qualities of outﬂow water.

ῐῌ+  45 MNOP Bmg LQ+, mS cmQ+D
Table +



T-N

NO--N

COD

TOC

TIC

Cl

EC

T-P

ῌ
῍
῎

24+
+,4,
+.41
++40

042
++40
+-4+
+*4/

04+
.4/
,4.
.4.

-4.
+43
+4.
,4,

34+
14/4.
14-

-/4*
-043
-+4*
-.4-

,/,03
,11
,01

*4*.
*4*.
*4**4*.

NO Daily mean values of concentrations of outﬂow water

3  +/ 

,   ῍ 

-ῌ-ῌ+



NO--N ῏῎NO--N 45

60789:;< !" #$%&'()*+,- .

=> ? @A&3 BC῏1D ῌ῎ / '(0123

)IJ'(K3

 EFGH45 :  f)hRijk[\.6¹º3»¼

?]^:

77

 3 &$86 +/ &M !"#Cl ῐ)*+,#  ῑC_D:"#!

N* )7`

aF*+3

TOC, pH, DO E3

COD,

NO--N, EC   b

cd!e<=,?

. 
.+ 
ῌ0"  NO--N ¹ COD TU

Fig. 0Relationship between ﬂow rate and theconcentration of NO--N and COD of
outﬂow water.



NO--N 

.++ 

fghRijk[\<3l,#lmno45pqrs

tuq +321v 

lpqf) NO--N lw!

p#? tuq +330 +332 a, ,*** ,**+

Tabuchi, ,**+v , ῐ

XLxXoῌexptaῌqv

  2
mg L+ 



 

+. mg L+.

ῑ

 !"#

 $

%
3 & +/ &&'$ %(!--,;; XL ; V NO--N  tmg L+v Xo ;" NO--N  tmg L+v a ; [\Uy tm d+v
q;

t



tm d+v  }=

<fz[,?M{|z#?8~$%& 'Iv ῌ l<( x <COD, TOC, TIC 

COD )*+,#

- $

ῌ

)

./0123 45 (

=3$IK $I!

!ῐ*+
TOC 6)*+,#78

/09: # ;<=,#XxxXoῌexptaxῌqLv. (!ῐ  >?@A +/ &;l

6 yTyd3 ;<=3῍Xx ; ( x  tmg L+v x ; ( tmv L ;o 

@B 3 &$86tmv

ῌ l XL " Xo [\Uy

TIC 6)*+,#   CD

a 7$ ' q  - )> ;<=3)! >? TOC E@A@B$8

l

6  u *+!DP,d---!!"#78 ,**+ -.*

T-P 

T-P )F!GH!$IJK*+66,#! ?L@A +/ & 3 &$86--.

 ¡¢£¤¥/ῌ&0¦§<¨©ª«,#¬p ? t Proc. ,**+v ;$I!7`jk[\"#;l6­®1  ¯2i<3°±²³w!3 ;´)

pHpH )*+,#µ)hRijk[\¶ R tg m, +/ &M 2 N* *+,#78 O- P$ QR+

d v " < qo,  < qL 7 STU,#--/RxqoῌXoqLῌXLDODO 6)*+,#VW 3

Rxqo XoqL Xoῌexptaῌqv

EC, ClEC )Z(,#NO--N [\῎῎ l ῌ l<·"3 &6 +. mg L+ N*)XY--02hRijk[\?]

῏)F,!°¸ qxqoxqL !



78

ῌῌ1
Fig. 1

  33  ,**/



Changes of water qualities in ﬂow process.

º :  »mij¼a

79

=98D_ GHI1234.)q


RqXo+expaῌq  Xo> -r90ῒ1234rs* 0ῐ1234῍:;= t U=u *.*+ m d+ j <8 R  qa  !"# $ %&.+,> =%v9-wx5 my Q
%opbcz{?@ ao.+.

 NO--N  XL 

XL ῌM|}~ ! ao " a #CC:; my T z{ Xo 

)* ?@ ao % 9- 9- +ΐ/ ,-./0ῐ12345'0ῒ

U98t:;]9-m C%i:;%XL  ῌ

$'(   q

12346  7(8 XL 9-

^A U:;C ao % 98UGHI%^:;.<8=98>?@ aA- d[-imy 

=98>-A B'(C1234 XL

Xo D.E XLῌXo FGHI%Jΐ, &9- KLM XLῌXo  ῌ%N(

XLῌXoexpaῌq῎q .<8S5

U q % - VW$-XY a

T

S9-5%Z[%B)

t C1234FGHI *.*+,*.*+- m d+ q> Jΐ,  ao ._ a I )> >/  Xz{ ._)


8>  ¡- ¢=£¤3swS> %&©98>

aqῌlogeXLῌXo῏ Jΐ, &9-C1234 q

XLῌXo F

GHI%\]98 C1234FGH?@ a %^A- UI *.*-- *.*-, *.*-, GH *.*-,
_`aM|)./9- UM|5'my¥ ¦§9 ¨98>>   myr

%N98

῎

?@ a

ao  a I._R* *.*+**.*+/ m d+ O aῌq P@Q@JR(  at U

I%n:;98+ΐ2 98 X q .<8)*S95<- 90ῐ1234 ,0 :i ao :;=
l> 959X?@ a  +, :,+ :n9-mI ª> >/:;=%98> (iijmy«¬w t %&©98>
0ῒ1234 ao, a(i:;

:;=

8>

3 : ­*<--At +ΐ3

59bcd[./C:;^A- a :;=®9>:;=%&9-  ao n:; +/ :,+%98>:)> +2 :I ¯ª%&98>  (F.+-  a 

omy ª>:;i9-mr5't a Fd ῏o:°)I%&  U±:°%e<8C:;?@ a %^A-f gh.<8ijkl )I%&98> ² * :«³]m nmGHI% q)>I ´µ98>²¶ t ao   * :«³9-

X?@ a :;=%+ΐ2 &9- 0ῐ 0ῑ 0ῒ1234  `a *.*- m d+ %opL*_ a9> m· TOC K ?@ ¸-=%98> TOC KFo +, :

$ῌ, C1234FGHI n:; 3 :0 :
Table ,

Mean values of each stage

1234 ]m ]mK nmK KLM  ?@ z{?@ X¹@
qo
Xo
XL
XLῌXo
R
a
ao
f
m d+
mg L+
mg L+
g m, d+
m d+
m d+
ῐ
ῑ
ῒ

*4*.*
*4*1*4+-0

+140
+242
+041

042
++40
+-4+

*4-3
*40,
*413

*4.3
*402
*40*

*4*-*4*-,*4*-,*4*+*4*+,
*4*+,

,4/
,41
,41

+, J»c ¹ 33 ¼ D,**/F80

῎ῌ2
Fig. 2

c|:;µ¶ a, ./:;µ¶ ao ±²·¶ f

Z[

Changes of coe$cient of nitrate removal rate (a), coe$cients of nitrate removal rate inlaboratory (ao) and ﬁeld coe$cient for nitrate removal (f).

89:;<=>?@ABC

 DE* ,**+F ()G!"H῎8I<JKLM
NCOPQ- !   $8RS$T#    ()GUVW" +2 -  X$T
!M Y!#R+,Q! Z[\]^NK_`KJ  #aMb=cMde-῏ fg hij(῍kl./mnop
qr! stuvwxyz8{|}~! Q{| Dc|8 c|F 
῎ῌ3
Fig. 3

c|:;µ¶ a  ao ¸
WZ D¹ῌ5º F

TOC 

Changes of the values of a, ao and TOC
concentration (ῌ stage).

{| ?#\]#l  fg [ B^ 8#fKJ  D
44wF \]#l b=cM
@ABC  D*ῌ/ +332F
()*" #aR ¡ 
 !  8#44w"¢£¤+2 ῌ +.0+.3 mg L +



 



-  +.- mg L

  

TOC + a  

 !"# $%&'()* +,- ./0)!"1234567

 KJ\]MC¥N K¦§8WZ
M!M¨ ©qr^+,qrCT K
Jª\]¡  «¬­®¯\!M.ῌ+ῌ/ ῑ῍ῐ῏ fao  a° " ./mn±² ³M ´ : »ZY¸¹º./D¼yhrs



 
!" # $%&'()*+# ,,- -./012

345 6789 +33/9 +3309 ,**+:

;a2ao <9 $-=>?@eh2
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