（attachment 3）

LABORATORY EXPERIMENT BASED ON IN-SITU LANDFILLANAEROBIC-AEROBIC CHANGEOVER CONTROL AND WATER SUPPLYING FORMETHANE GAS COLLECTION AND WASTE STABILIZATION
Isamu Norimatsu1, Yoshokazu Otsuka2, WON Jong-Choul3, LEE Kyeong-Ho3, Masataka Hanashima4,TohruFuruichi4
1 HAZAMA Corp.
2 OKUMURAGUMI Corp.
3

SUDOKWON Landfill Site Management Corp.

4

The landfill systems & technologies research association of Japan (LSA, NPO)
401 Chateau Takanawa, 3-23-14 Takanawa, Minato-ku, Tokyo 108-0074, Japan

ABSTRACTThe realization toward a sustainable loop-style exploitation society has involved various processes all over theworld, one of which is how to effectively use the waste that had been piled up at final landfill disposal sites. So many
researches on this problem have been reported. However, they were often uniquely and separately conducted bycountry to country. From a point of view of international contribution, it would be much better if the results of thoseresearches are mutually shared and effectively extended for use under international research cooperation for making
potentially new achievements.
For international cooperation and contribution, a research on the dumping waste of final landfill site is carried out
at the Research Institute NPOLS in cooperation with Sudokwon Landfill site management Corporation (SLC) of
South Korea in 2006. The research title is “Final disposal landfill of anaerobic-aerobic changeover style forcollecting methane gas as well as early stabilizing dumping waste”. According to this research, it is considered thatcollecting methane gas generated from landfill dumping waste and rationally using it for producing electric energy,
and promoting discharge of decomposed organic components and heavy metals from dumping waste in earlystabilization should be designed as a definite landfill control method. It is explained that, depending on the waste’s
characteristics at voluntarily phase (stage), periodically alternating the created atmosphere inside the dumping waste
layer from anaerobic to aerobic condition, as well as sprinkling the dumping waste with water to change its water
quality and amount will force the waste to generate methane gas and be stabilized in suitable landfill condition.
In this cooperative research, Column tests are carried out at SLC experimental site using general waste andincineration ash from South Korea. From total 6 Column tests, five cases (Cases 1 ~ 5) involved general waste
containing fresh materials, and the left one (Case 6) is filled up with incineration ash. Since beginning experiment in
Nov. 2006 to present, these 6 columns were kept in anaerobic condition and periodically sprinkled with water. The
sprinkling water amounts were different, as 0.5L/week for cases 1, 2 and 6, and 1.0L/week for cases 3, 4 and 5. In allcases except for the case 1, the water exuded from the column was circulated.
To report the experimental process, this paper presents experimental outlines as well as various data analysis
results and discussions.
Keywords: methane gas, stabilization, anaerobic-aerobic, landfill

（attachment 3）
methane gas from the landfill dumping waste;

INTRODUCTION
The realization toward a sustainable loop-style2) To examine the method of promoting stabilization of

exploitation society has involved various processes all

landfill dumping waste.

over the world, one of which is how to effectively use

In his experimental study, 6 column tests are

the waste that had been piled up at final landfill

conducted, all of which have been set up with anaerobic

disposal sites. So many researches on this problem havecondition at the beginning. The anaerobic condition thatbeen reported. However, they were often uniquely andis purposely set for collecting methane gas, is also

separately conducted by country to country. From a

expected to be good for follow up stabilizing because

point of view of international contribution, it would be

difficultly decomposed raw materials would be gasified

much better if the results of those researches are

and hence easily stabilized under this condition.

mutually shared and effectively extended for use underinternational research cooperation for making potential

EXPERIMENTAL OUTLINES:

new achievements.

Purposes of the column tests

For international cooperation and contribution, aIn this experiment, 6 column tests were carried out,

research on the dumping waste of final landfill site isamong which 5 columns used general municipal waste

carried out at the Research Institute NPOLS inand the other one used incineration ash from South

cooperation with Sudokwon Landfill site management

Korea. For each column test, depending on alteration of

Corporation (SLC) of South Korea in 2006. The

air supplying pattern and water supplying amount,researchofdifferences in amount, speed and composition of theanaerobic-aerobic changeover style for collecting

generated gas were measured. At the same time, themethane gas as well as early stabilizing dumping

inside temperature of the column, the amount andwaste”. According to this research, it is considered

properties of exuded water were analyzed to clarify thethat collecting methane gas generated from landfill

column condition.

title

is

“Finaldisposallandfill

dumping waste and rationally using it for producing
electric

energy,andpromotingdischargeof

The used dumping waste

decomposed organic components and heavy metals

Material for filling up the columns 1 to 5 werefrom dumping waste in early stabilization should be

relatively composed of dumping waste from the 2005

designed as a definite landfill control method.

bring-in waste (general living activity waste) in 2005 of

A series of column tests was carried out. In this paper,

South Korea metropolitan landfill. This bring-in waste

column test layout, dumping waste characteristics andmaterial was cut by scissors in to pieces of 20 ~ 30mm

results of various data analysis for a testing period fromfor making test samples. The compositions of the

beginning to present are reported.

general dumping waste used for the column tests 1 to 5
are summarized in Table 1, which indicates that about

PURPOSES OF STUDY
The two main purposes of this study are:1) To confirm the method of effectively generating

97% of the waste is combustible.
On the other hand, compositions of three componentsof the used general dumping waste and incineration ash

（attachment 3）
Table 1 General dumping waste compositions
Combustible
Vinyl

Paper

39.42

38.07

Incombustible

Raw
Fiber Wood material

Glass

Metal

Other

2.04

2.15

1.13
3.31

0.03

5.2
96.69

11.96

Table 3 Component element analysis andamount of heat generation from generaldumping waste and incineration ash

Classification

C

100

analysis and the amount of generated heat are shown in
Table 3. The physical properties of the used materials
such initial weight, density and dry weight, initial
weight of water, initial water ratio and initial content
are presented in Table 4 for all tested columns.

H

O

N

S

Vinyl/Plastic 79.1 7.0 8.9 0.9 ND
Paper
34.6 4.6 42.3 0.3 ND
Fiber
54.7 5.2 36.7 0.7 ND
Wood
47.6 5.7 43.8 0.5 ND
Raw material 39.0 5.0 34.9 2.7 ND
52.8 5.50 26.6 0.84 ND
Incineration ash
ND ND ND NDGeneraldumping waste

are shown in Table 2, while the component element

Generated heat(cal/kg)
Low
High
position position
8849.1
9,267
2226.3
2,625
5203
5,509
4632.75,017
3394.18
3,925
5106.95,510.6－－

Element analysis (%)

Table 4 Column initial index properties
Column

1

2

3

4

5

6

As seen from Table 2, when the combustible

Filling up waste

General dumping waste

component is of about 65%, the incineration reduction

Column volume
(cm3)

26494

26494

26494

26494

26494

26494

weight is about 2%. From Table 3, up to 53% of theInitial weight (g)

11127

10332

10597

11922

10597

42125

0.42

0.39

0.40

0.45

0.40

1.59

9143

8490

8708

9796

8708

42125

1984

1842

1889

2126

1889

1424

17.83

17.83

17.83

17.83

17.83

3.38

21.70

21.70

21.70

21.70

21.70

3.50

general dumping waste was carbon (C). From Table 4,
the initial water content was 21.7% for columns 1 to 5,
and 3.5% for column 6.
Next, decomposing potentials (such as easy, difficult
or unable decomposition) of the general dumping waste
used in filling up columns of cases 1~ 5 are established

Initial density(g/cm3)
Initial dry weight(g)Initial weightof water (g)Initial water
ratio (%)
Initial watercontent (%)

Table 5 General dumping waste types
General dumping waste

in Table 5. Actually, in South Korea, directly dumpingof raw waste to the landfill has been prohibited sinceType

2005. Therefore, by thoroughly management of
separately collecting raw waste, at present thepercentage of the raw waste is about 12% lower than in
the past. In 1gram of the tested material, the ratio C/N
was 48, which is out of the suitable range (C/N = 10 ~General dumping waste

Table 2 Compositions of three components ofgeneral dumping waste andincineration ash (percentage)
Classification
Vinyl/Plastic

Incineration ash

Component

Decomposible
EasilyDifficultly
decomposable decomposable
Raw waste
Paper

Percentage
by weight (%)

50.03

Organic
dry weight
DS (g/kg)
Organic
Concentration(g/kg)

353

Fiber
Wood

Nondecomposible
Total
Vinyl
Non-combustible(glass, metal,
others)

7.24
57.17

42.83

100

401

822

－

－

－

－

68
421

270

58
328

41

82

Water
6.65

Ash
11.73

Combustible
81.62

Paper

25.05

15.66

59.29

Fiber

4.20

14.94

80.86

Wood

12.75

9.46

77.79

Raw material

43.47

19.75

36.78

the fact that the used dumping waste was relatively less

Incombustible
0.0
Weighted average
17.83
efficiency

3.31

0.0

material rich in N such as raw waste.

17.23

64.94

94.66

1.96
(incinerated volume
reduction)

Incineration ash

3.38

Ratio C/N4820) for methane generation. This is considered due to

Photos 1 and 2 illustrate the tested general dumping
waste and incineration ash, respectively.

（attachment 3）
Table 6 Test cases
Case
Fill up
Waste

ColumnColumn 2
1

Column6
Incinerat
General dumping waste
ion ashAnaerobi
AnaerobiccÆAerobÆAerobicÆAerobic
icÆAnaerobic
144ml/
Maintain
Maintain
Maintain
144ml/
week
Suitable
Suitable
Suitable
week
+
Water
Water
Water
+ exuded
exudedwater (exuded water (exuded water (exuded water
water
amount recirculated) recirculated) recirculated)amountAirsupplying

Column 3

Column 4

Column 5

Water
supplying(Preparing 144ml/
week
St)(3 times in
Nov.)
Water
supplying
0.5
0.5 L × 2
0.5 L × 2
0.5 L × 2
0.5L/
(FirstL/week
/week
/week
/week
week
0.5 L/
Stage)+exuded +exuded+exuded+exuded+ exudedweek
Dec.14~amountamountamountamountamountJan.25(7 weeks)
Water
0.5
0.5 L × 2
0.5 L × 2
0.5 L × 2
supplying
L/week
0.5 L/week
/week
/week
/week
0.5 L/(Second(recircula(recirculate(recirculate (recirculate (recirculate
weekStage)
teincluded)included)included)included)
Jan.26 ~included)Present
Gas
analysis
Generated amount, CH4, CO2, O2, N2, H2S, NH3 (GA used)
Once/week

Photo 1 general dumping waste

Photo 2 incineration ash

Waterproperty
AnalysisOnce/week

TEST CASES AND TESTING CONDITIONS
The test cases are summarized in Table 6.

Generated amount, pH, COD, EC, BOD, alkali level, T - N,
NH4+, NO3- , NO2- , SO4- , CL-, ORP, heavy metals (forincineration ash only)hydrometer.

1) ater supplying (Preparation stage): (in November)

2) Water supplying (First stage) (Dec. 14 ~ Jan. 25):

By setting the amount of water supplying to the

According to the water supplying plan, the water was

landfill waste at 35% of the annual precipitation at theinfused 3 times in November. However, because

landfill site, and acknowledging the ten-year average

exudation of water was not occurred, the amount ofprecipitation of Nigawa region is 1218mm, the amountsupplying water was changed to 1 L/week instead ofof water to be supplied to a column is calculated as

144 ml/week as calculated before. The reason for doing

following:

so is explained as following:
2

1218mm/year × 0.35 × column area (176 cm ) / 52
weeks per year = 144 ml.

・ According to some reference data, it would
require to infuse 200 liters of water to 1 ton ofThat is the amount of water to be supplied to thecolumn once a week. The water would be infused to thewaste inside the column by fix pump. Since the-5

dumping waste to reach the most suitable wateramount;・ If considering that, in order to reach that suitable

permeability of the landfill is 2~5×10 cm/s, thewater amount the infusing water amount should

infusing rate is calculated as following:

be expected at 2L/week since the weight ofWater infusing rate = area × permeability = 176

dumping waste for filling up a column is about2

10 kg. However, to compromise with the-5

cm ×(2~5×10 cm/s) = 21 ~ 53 ml/min.
It was determined that the most suitable water ratio

calculation based on precipitation condition, theof the landfill waste is 60%, the amounts of water

water supplying amount was set relatively atexuded and infused are adjusted by monitoring with

1L/week.

（attachment 3）・ During experiment, the amount of supplying

fixed by bolts at 12 positions.

water was increased step by step. Therefore,

5) At each measurement hole in the middle height ofonce the modified water amount is confirmed,each

any variation in characteristics due to different

measurement.

water amount can be clarified.

6) A pipe of 10mm diameter is inserted from top tocolumnpart,hydrometerisinsertedfor3) Water supplying variation (Second stage) (Jan.26 ~bottom of the column for sucking in the generated gas

present):

from all dumping waste layers, as well as supplying air

Although the experiment was carried out into them.

accordance with the water supplying plan mentioned in7) A gas pack is equipped in order to collect thethe First Stage, however due to a continuously

generated gas from the waste layer, as well as for theincreasing tendency of water exudation, re-circulation

gas phase from the waste’s pores to escape whenof the exuded water amount was modified from thesprinkling water.

intended value. The supplying condition from the First

8) To be able respond necessarily, the gas phase

Stage to the Second Stage was changed on Jan. 26,

adjustment hose is set in close condition by ordinary

2007. Actually, in addition to the exuded water, the tap

valve.

water was also used for supplying.

9) Waste monitoring holes (diameter of 10mm) are set
at 3 locations around the column so that measurement

COLUMN TEST DEVICE INSTALLATION
Installation of column test device is outlinedof temperature, water, gas etc… can be done.
10) The bottom cover of the column is designed inhereafter.

funnel shape so that the water extraction device can be1) On the assumption that the filling material sample

easily clung to.

inside the column may break (smash) at about 20mm,11) The bottom of the column is filled with gravel andthe device is made of clear acrylic for enabling

unwoven textile on its top for good water drainage.

observation of inside.

12) The column is wrapped from outside with paper2) The column test device consists of 3 equal column

and then with heat insulation material. When taking off

parts, each of which is 50cm in length and 15cm inthese wrapping layers, the inside stabilizing condition

diameter, able to be connected together into a 3-stage

can be observed.

column of 1.5m high. The test material will be filled in

The outline of column test equipment is presented ineach part of the column before connecting.

Figure 1. Photo 3 illustrates the set up of column test.

3) The column was designed strong enough withthickness of 10mm, a flat cover on the top and 3

EXPERIMENTAL RESULTS

measurement holes for sampling on the side of the

The test results obtained for the period fromcolumn (each at the middle height of the upper, middle

beginning to present (April 3rd, 2007) are reported

and lower column parts).

hereafter.

4) The joint between the 2 column parts is about 20mm1) Water inside the column

thick, sealed up by O-ring and sealing material, andIn order to clarify the water content and the water

（attachment 3）
排出ガスチューブ
exhaustgas tube

watering
tank

散水タンク

150mm
150mm

multiplication
flow meter

The exuded water was re-circulated as part of the

積算流量計

air injection tube
supplying
空気注入チューブair
supplying
空気注入装置airsupplying water in all cases (2 ~ 6), except for case 1.
Actually, since 80cc of the exuded water was used forwater quality analysis, the tap water was used insteadhole for sampling

500mm
1/3：500mm

測定孔

gas pipe

中央ガス回収管φ10mm(送風管兼用)for the inadequate amount of supplying water. Based onrecording of the amounts of water supplied and exuded,

カラム分割長さ：500mm

clear acrylic
厚み 10mm
10mm

500mm

カラム反応器(不透明アクリル製)

column material are plotted in Fig.2 and Fig.3,
respectively.

hydro
水分センサーmeter

Water supplying
stage 1
水供給第1期

250mm
250mm

浸出水再循環チューブtube
re-arculation

100

φ40mm
液状
water
pump
ポンプ
支持台

50mm
50mm

浸出水集水管（伸縮管）

Amount of
supplying
給水量
water

△ Column
2槽 2□ Column
3槽 380
直径 40mm

Water supplying
Stage 2
水供給第2期○ Column
1槽 1

90

Water
含水率(%)
ratio (%)

1/3：500mm
500mm

1500mm

廃棄物充填深さ：1500mm

variations of water ratio and water content of the tested● Column
4槽 470▲ Column
5槽 5

0.5L×2回/週
0.5L
× 2
times/week■ Column
6槽 6

60
50
40

Incineration ash
0.5L/週0.5
L/week

30
20

焼却灰

10

tank

貯留槽

0
0

Fig 1 illustrates the set up of column test

20

40

60

80

100

120

経過日数
(日)
Elapsedtimes (days)

Fig 2 Column water ratio variation
Water水供給第1期
supplying stage 1

Water
supplying Stage 2
水供給第2期250○ Column
1槽1

給水量 ofAmountsupplying
0.5L×2回/週
water

Water含水比
content(%)(%)△ Column
2槽2
200 □ Column
3槽3● Column
4槽4▲ Column
5槽5150 ■ Column 6
6槽

0.5L × 2
times/week100

Incineration ash
0.5L/週0.5
L/week

50
焼却灰

0
0

20

40

60

80

100

120

Elapsedtimes (days)
経過日数
(日)

Photo 3

set up of column test

Fig 3 Column water content variation

ratio of the column, the amount of water in the filling

The water conditions of the tested column material

waste was measured. Actually, for columns of case 3

on Feb.23rd, 2007 are summarized in Table 7 for all 6

and case 4, the results indicated that suitable water levelcases. According to that, for columns 1 and 2, by

has been maintained.

supplying water at 0.5 L/week, the water ratio was

As shown in Table 6, the water is supplied to theabout 35 ~ 45%, while the water content varied fromcolumns at a rate of 0.5 liter/week for cases 1, 2 and 6,

50~80%. For columns 3, 4 and 5, by adding water at 1

and 1 liter/week for the case 3, 4 and 5, respectively.

L /week (actually 0.5 L twice a week), the water ratio

（attachment 3）
Table 7: Amounts of supplying water andleached out water of all column tests (Until
Feb. 23rd, 2007) (Unit : mL)
Total amount ofwater supplying
Total amount ofleached out
water
Increase inamount of water
Initial amount ofwater
Column wateramountInitial dry
weight (g)Water 水供給第2期
supplying Stage 2

50

Column 1 Column 2 Column 3 Column 4 Column 5 Column 6
6,000

8,970

24,87524,19025,855

8,518

40
○

3,228

2,772

4,865

4,105

11,995

12,8808,815

15,3759,920

15.965

4,729

3,789

1984

1842

1889

2126

1889

1424

4,756

5,947

14,76917,501

17,854

5,213

9,143

8,490

8,708

9,796

8,708

42,125

Water ratio (%)

34.2

41.2

62.9

64.1

67.2

11.0

Water content
(%)

52.0

70.0

169.6

178.7

205.0

12.4

温度 (℃)
Temperature(℃)

Parameter

Temperature
温度 (℃) (℃)
Water supplying
stage 1
水供給第1期

△

30

□
●
▲

20

■
◆

Column1槽 1Column2槽 2Column3槽 3Column4槽 4Column 5
5槽
Column 6
6槽
Outside外部温度
temperature

10

0
0

20

40

60

80

100

120

経過日数
(日)(days)
Elapsedtimes

Fig 4 Column inside temperature variation

was 60-70% and the water content was as high as

was about 10℃ and increased to about 25 ~ 30℃ after

180~210%. From these values and considering the

20 days, then gradually decreased to about 20~30℃,

initial dry unit weight of the filling material of 0.35 ~and again rose up to nearly 30 ~ 40℃ on the 50th day

0.40 g/cm3, it can be said that the water had been

and thereafter. In all cases, the inside temperature of the

sparkled to a quite high saturation degree. Therefore,column was about 0 to 10℃ higher than the outside

looking at the amount of water come in and out, thetemperature. Especially, for columns 4 and 5, suchamount of water inside the column is subtracted indifference

respond to the amount of supplying water.

phenomenon indicates that some reaction was taking

was

even

more

remarkable.

This

On the other hand, for the column filled withplace inside the column. However, since variation ofincineration ash in case 6, although the sprinkling water

the outside temperature was similar, it is consideredamount was 0.5 L/week, too, the water ratio and waterthat the inside column was more or less influenced bycontent were as low as 13% and 15%, respectively.

the outside air temperature. Also, recorded low values

2) Temperature inside the columnof temperature were due to accidental breakdown of the

To clarify the micro-bio organic decomposition

warm air conditioner on the days 15th, 63rd and 110th.

condition, temperature of the material layers inside the

Next time, it is intended to maintain the indoor lab

columns was measured. At the same time, the outside

temperature at more than 40℃ to investigate.

temperature was also measured. Variations of the inside3) Exuded water quality

and outside temperature are plotted in Fig.4 based on

Water quality analysis of the exuded water wasdata of temperature sensor of the columns. During

carried out to clarify the wash out and decomposition

experiment, a warm air from air conditioner wasconditions. Fig. 5 illustrates the variation of pH of the

supplied to maintain the temperature of the waste layers

exuded water. The pH value is purposely measured forat 20 ~ 30℃ as normal. At the beginning of the tests

evaluating up to which level the bio-reaction is possible.

(Dec.14th, 2006) the inside temperature of the columns

The general waste used for filling up column cases 1 ~（attachment 3）
respectively. For column 1, values of both COD and

pH
PH

pH
PH

Water
supplying stage 1
水供給第1期

Water
supplying Stage 2
水供給第2期

14
13
12
11
10
9
8
7
6
5
4

BOD were slightly decreased, while for columns 2 and3 considerable variations were not observed. However,
○
△
□
●
▲
■

1槽1
ColumnColumn2槽2Column3槽3Column4槽4Column5槽5Column
6槽6

for columns 4 and 5 from the 80th day on, sudden
increases in COD and BOD were recorded. For column
6 filled with incineration ash, both COD and BOD
values were low and did not change significantly.
Variation of ammoniac nitrogen in exuded water is

0

20

40
60
80
Elapsedtimes (days)
経過日数

100

120

Fig 5 Variation of pH value of the exuded water

shown in Fig.8. For column 1, the level of NH4+-N inearly stage was 400 mg/L, which gradually decreased
thereafter. For columns 4 and 5, a sudden and5 has the pH value of 6 ~ 8, while the incineration ash

remarkable increase in NH4+-N was observed from thein column 6 has pH of 10 ~ 2.

85th day on. The NH4+ - N content was lowest in the

Variations of COD value and BOD value of theexuded water are presented in Fig.6 and Fig.7,(mg/L)
Water 水供給第2期
supplying Stage
2 (mg/L)

Water supplying
stage 1
水供給第1期

case of column 6 filled with incineration ash.
Variation of nitric nitrogen NO2–N and nitrate
nitrogen NO3-N are shown in Fig. 9 and Fig. 10,

60000

Water supplying
水供給第1期 stage 1
1200

50000

1000

○ 1槽 Column 1

40000△ 2槽 Column 2□ 3槽 Column 3

30000● 4槽 Column 4▲ 5槽 Column 5■ 6槽 Column 6

20000○ 1槽Column 1

800+
NH4+-N
-N
NH4

COD
COD

（mg/L)2 (mg/L)
Water
supplying Stage
水供給第2期△ 2槽Column 2□ 3槽Column 3

600● 4槽Column 4▲ 5槽Column 5■ 6槽Column 6

400

10000

200

0
0

20

40

60
80
100
Elapsedtimes (days)
経過日数

120

0
0

Fig 6 Variation of COD value of the exuded water

40

80

100

120

Fig 8 Variation of NH4+ - N of the exuded water
Water水供給第2期
supplying Stage（mg/L)
2 (mg/L)

水供給第1期Water supplying
stage 1

60000

60

Elapsed経過日数
times (days)

水供給第2期 Stage（mg/L)
Water supplying
2 (mg/L)

水供給第1期Water supplying
stage 1

20

100
50000

△ 2槽 Column 2○□ 3槽 Column 3● 4槽 Column 4

30000▲ 5槽 Column 5■ 6槽 Column 6

20000

NO
2-N
NO
2-N

BOD
BOD

80

○ 1槽 Column 1

40000

60

△
□
●
▲

40

■

10000

1槽
Column 1
2槽
Column 2
Column 3
3槽
Column 4
4槽
Column 5
5槽
Column 6
6槽

20

0
0

20

40

60

80

100

120

Elapsed経過日数
times (days)

Fig 7 Variation of BOD value of the exuded water

0
0

20

40

60

80

100

120

Elapsedtimes (days)
経過日数

Fig 9 Variation of NO2 - N of the exuded water

（attachment 3）
Water supplying
stage 1
水供給第1期（mg/L)
Water
supplying Stage
2 (mg/L)
水供給第2期

demonstrated a slightly decreasing trend. Arsenic (As)100started leaching out from the 64th day on. Cyanic (CN)80

was slightly decreased compared to the initial stage,

NO
3-N
NO
3-N

○
△

60

□
●
▲

40

■

1槽
Column 1
2槽
Column 2
3槽
Column 3
Column 4
4槽
Column 5
5槽
Column 6
6槽

however essential alteration was not observed. Only
copper (Cu) was presented with a quite high value.
4) Generated gas amount
Variation of the generated gas amount is shown in

20

Fig. 11. After 80 days, the amount of gas generated

0
0

20

40

60
80
Elapsedtimes (days)
経過日数

100

120

from column 3 was considerable, however, for the otherFig 10 Variation of NO3 - N of the exuded watercolumns it was quite little. Therefore, investigating on

respectively. Generally, both NO2–N and NO3–N

countermeasures for early generating gas is needed inshowed values below 30 mg/L during the tests.

the next time.

However, for columns 4 and 5, a significant increase in
NO2–N was found from the 85th day on. No

9remarkable change was occurred with the concentrationwater from column 6 filled with incineration ash aresummarized in Table 8. Comparing the concentration of

ガス発生量（リットル）
NO2-N

Results of analysis of heavy metals in the exuded

8

Generated gas volume (L)of NO3–N.

水供給第2期（リットル）
Water
supplying Stage
2 (L)
(L)

水供給第1期Water supplying
stage 110

heavy metals at the time of making sample with that

○

7

△

6

□

5

●

4

■

▲

1槽
Column1
2槽
Column2
3槽
Column3
4槽
Column4
Column55槽
Column
6
6槽

3
2
1
0
0

obtained from the exuded water, it was confirmed that

20

40

60

80

100

120

経過日数
(日)(days)
Elapsedtimes

Fig 11 Variation of generated gas amountmercury (Hg) had not been leached out with water.
Also, concentrations of cadmium (Cd) and lead (Pb)were almost zero. Concentration of chrome (Cr)
Table 8 Analysis results of heavy metals inleached out water
Measurementday

Elapsedtime(days)

When making
sample－07/1/421
17/1/12 29
07/1/19 36
07/1/26 43
07/2/250
07/2/957
07/2/16 64
07/2/23 71
07/3/278
07/3/985
07/3/16 92
07/3/23 99
07/3/30 106
Standard valueof discharge water

Hg

As

Cr

Cu

Cd

Pb

CN

DISCUSSIONS ON TEST RESULTS
From the test results of a period of 120 days since thestart of experiment, following conclusions can be
drawn:
・ Tested material components: for the general

0
0
0
0
0
0
0
0
0
0
0

0.379 13.25 0.005 0 0.035
0.243 5.484
0
0 0.0210.212 6.516
0
0 0.0160.212 6.516
0
0 0.0150.222 2.527
0
0 0.0150.232 6.081
0
0 0.0160.18 5.798
0
0 0.015
0.195 7.336
0
0 0.0130.172 13.17
0
0 0.0150.163 11.87
0
0 0.0140.135 7.821
0
0 0.012No leached out water－ (Too little amount of leached out water)

0.005

0.222
0
0
0
0
0
0.052
0.081
0.087
0.092
0.056

0.1

0.5

3

0.1

0.1

1

waste used in columns tests 1~ 5, about 97% of
the substance was combustible (vinyl, paper,
fiber, wood, raw material) and 3% wasincombustible(glass,metalsandother)

substances. For that general waste, the averagecomponent compositions including water, ahs
and combustible were 18%, 17%, and 65%,
respectively. For the incineration ash used in（attachment 3）column 6, the component composition wasincreasing trend. Especially, for columns 4 and 5,

characterized by 3% water, 95% ash andthe increase was remarkable.

incinerated weight reduction 2%.

・ Ammoniac nitrogen:during 6 weeks of・ Water supplying: 3 regimes of water supplying

circulating water (Water supplying First stage)

were deployed: 0.5L/week, 0.5L/week + exuded

the NH4+-N showed a slightly decreasingwater, 0.5L × 2 times/week + exuded water.

tendency. However, from the 85th day on, aWith increasing the amount of water circulation,

significant increase in concentration of NH4+-N

the

and

was seen for columns 4 and 5, while nomonotonously during the 6-week period of First

considerable change was observed for the otherstage water supplying. After that period, due tocolumns.

water

ratio

increasedgraduallyusing mainly the exuded water for supplying,・ Nitric nitrogen: from the 85th day on the

only a minor increase in the water ratio wasconcentration of NO2–N in the exuded water

maintained.

notably increased for columns 4 and 5.

・ Temperature:

after

setting

up

the

test,

・ Heavy metals: from the results of element

temperature outside the column was about 10℃

analysis of heavy metals in the water exuded

20 days. After that it was maintained at 20~

from incineration ash, rather high concentration

30℃. Although inside the column, temperature

was found for copper (Cu) only.

was about 0 ~ 10℃ higher than that outside,・ Generation of methane gas: Except for the

however, it can be considered that such acolumn 3 where the gas was started generating

difference in temperature was not due to activity

from the 80th day on, for the other columns theof micro-bioorganic at this stage. The inside

generation of gas was almost not observed.

column temperature increased up to 35 ~ 40℃
from the 85th day on was seen for columns 4
and 5.

RECOMMENDATIONS
Although expecting that providing an anaerobic

・ The pH value: for columns 1 ~ 5 with generalcondition to the landfill waste would make the methane

waste, the pH value was in the range of 7 ~ 8.

gas effectively generated, however, for a period of 120

On the other hand, for column 6 withdays of the experiment the gas generation has almost

incineration ash, the pH value was about 10, but

not been seen yet. Therefore, it is recommended that

increased to 11 ~ 12 at present.

next study should focus on the problem of early・ BOD and COD values: during 6 weeks ofincreasing water circulation (Water supplying
First stage) decreasing tendencies of BOD and
COD values were found. After that, as theexuded water had been involved as a part of the
supplying water (Water supplying Second stage),both of BOD and COD values indicatedgeneration of the methane gas, for which the column
conditions and so on should be examined again.