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Waste water 2
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1
Waste Water treatment by
Multi Soil Layering Method
2
Land treatment
Sand filter
Septic systems (EPA)
Conventional method
Low permeability
> need large area
> Risk of clogging
Soil has high purification function, but is highly depends on
properties of each soil type.
Multi-Soil-Layering (MSL) Method
Some limitations
Increase the permeability Regulation and enhancement of the
purification functions
Background
The use of soil for water treatment has a long history in the world.
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The MSL method consists of soil units arranged in a brick-like pattern surrounded by
layers of zeolite or alternating particles of homogeneous sizes that allow a high hydraulic
loading rate.
Multi-Soil-Layering (MSL) Method
Wastewater
Treated water
Soil mixture layer (10-3 cm sec-1)
andisol : high soil aggregate formation, high phosphorus
adsorption ability.
sandy soil : large particle size and high permeability
on-site soil: low cost
iron : phosphorus adsorption, reducing agent
charcoal : high porosity, hydrophobic adsorbent, habitat of
microorganisms
organic matter : food for microorganisms, electron donor for
denitrification
Permeable layer (10-1 cm sec-1)
sandy soil: large particle size and high permeability
zeolite : high NH4+ adsorption ability, high CEC, high porosity
Pumice : high porosity, low cost than zeolite
charcoal : high porosity, hydrophobic adsorbent, habitat of
microorganisms
gravel
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Conceptual diagram of Multi-Soil-Layering (MSL) Method
Waste Water
Treated Water
The soil mixture layers
The permeable layers
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Treatment processes of MSL Method
PO 4 3- adsorption
CO 2 , CH 4
Wastewater
PO 4 3-
Zeolite
NH 4 + adsorption
NO 3 -
H +
Nitrification Soil mixture layer
(Aerobic)
Metal iron
Fe 2+
O 2
CH 2 O
OH -
N 2 , N 2 O
Denitrification
Charcoal
Hydropho-
bicity
Aerobic decomposition
N 2 CO 2
O 2
Fe(OH) 3
Aeration
+ NO 3
- +
Organic
matters
BOD
COD
(Anaerobic)
NH 4 +
Organic material
Fe
Fe(OH) 3
PO 4 3- adsorption
Anaerobic
decomposition
Permeable layer
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Characteristics of the MSL method
1. High purification ability
2. High removal efficiency of N and P
3. Stable high treatment performance against fluctuation of raw water
4. Low maintenance
5. Reuse of treated water and soil
6. Harmony with the landscape
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MSL
method Toilet
Restaurant
Ｎ
Ｐ
COD
Ｐ
Domestic wastewater
Treated water from wastewater treatment plant
Polluted
environmental
water
remove
N, P, BOD, COD, etc
Sewage system, community plant
Treated Water
Application of the MSL Method
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Park
Small scale community
Application case
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○Loading rate
BOD、T-N、T-P removal The standard is 100L m-2 day-1.
BOD removal only It can be increased up to 4000 L m-2 day-1
Performance of the MSL Method
Experimental results (in Shimane University)
type of water (loading rate) BOD T-P T-N
river, lake, raw water (mg/l) 25 2.7 12
treated water (mg/l) 5 1.7 4
(200-5000 L M -3
day -1
) removal rate(%) 77 44 52
domestic and toilet raw water (mg/l) 190 6.5 58
wastewater treated water (mg/l) 16 1.7 30
(200-2000 L M -3
day -1
) removal rate(%) 91 75 48
livestock wastewater raw water (mg/l) 1400 40 240
high polluted water treated water (mg/l) 47 5.4 92
(30-300 L M -3
day -1
) removal rate(%) 96 88 61
Ⅰ
Ⅱ
Ⅲ
treated water from wastewater treatment plant
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type of water (loading rate) BOD T-P T-N
[park] raw water (mg/l) 5.4 4.46 39.4
a public latrine treated water (mg/l) 0.7 0.04 15.5
(100 L M -3 day -1 ) removal rate(%) 81.7 99.1 60.7
[estate,office] raw water (mg/l) 44.1 4.72 45.8
a cooperative society office in
Osaka treated water (mg/l) 8.5 1.35 13.2
(30 L M -3 day -1 ) removal rate(%) 80.7 71.4 71.2
[house] raw water (mg/l) 53.2 7.82 64.8
advanced treatment of
domestic wastewater treated water (mg/l) 4.8 0.81 5.1
(100 L M -3 day -1 ) removal rate(%) 90.9 89.6 92.1
[river] raw water (mg/l) 15.7 - -
direct river treatment system
in Kumazoe River treated water (mg/l) 1.6 - -
(4000 L M -3 day -1 ) removal rate(%) 90 - -
Results of practical use
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Aeration pipe
100
100
100
100
100
100
100
150
50
50
50
50
50
50
50
1200
mm
100 600
mm
Masa soil
Plastic net
Gravel 40mm Porous pipe VU75mm
Drainage pipe Ceramic cups for collection of soil solution
Soil, Jutepellet , Iron Mixture
Jute net
Zeolite 1 - 3mm
Plastic net
Gravel 40mm
Vinyl sheet
Cross Section
1000
1000 2 000mm
Aeration
25 00
1200 1750
90 0
85 0
350 0mm
400 0
Air
Air
1000
450 1000
Waste water inflow
Treated water outflow
A
B1
B2
Toilet Gray
Water
septic tank
Plan of treatment
quantity:1m3/day
Actual loading rate:
100～250L/m2/day
Domestic wastewater treatment
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0
10
20
30
40
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
0
20
40
60
80
100
BOD
removal percentage
0
1
2
3
4
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
0
20
40
60
80
100
T-P
removal percentage
0
10
20
30
40
50
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
0
20
40
60
80
100
T-N
removal percentage
( m
g／
l )
( ％
)
Change of BOD,T-P,T-N concentration and removal percentage of treated water
Evaluation of system performance during the 10years operation
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Application case:
Treatment of Polluted River Water by the MSL Method
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Kumazoe River purification project
location of Kumazoe River and situation of the watershed
Enlarged view
Purification
facilities
Onga River
Onga River Onga River
Kumazoe River
purification facilities
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Kumazoe River basin
Iizuka Station
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The general situation of Kumazoe River
The catchment area 2.5km 2 ( the urban area: about 80%)
Length of river channel 1 .2km
River flow average of winter: 7000m 3 day
- 1
average of summer: 28000 m 3 day
- 1
Quality of the river water average BOD concentration of winter 55mg L - 1
average BOD concentration of summer 9 mg L - 1
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The contents of the project
The design parameters of the MSL method
Targeted quantity of the river water: 7000m3 day-1 (the target is mean river flow of winter)
Targeted quality of the river water: BOD 15.7 mg L-1 (on the average)
BOD 50 mg L-1 (on the maximum)
Targeted quality of the treated water: less than BOD 1.6mg L-1
(BOD removal rate: 90%)
The scale of the MSL method
Site area: the MSL method 1750m2
total 6 series: 5 series of 6 series are always alternate operations.
: pre-treatment system for SS removal (a contact oxidation system)
The construction details of the MSL method
The construction period: September,2002 ~ March,2005 (start: April,2005~)
The cost of construction: 7.7 hundred million yen
110 thousand yen per 1m3 day-1 of the water quantity
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A plan for Kumazoe River purification project
20m
15m 15m
15m 15m
15m 9m
Onga River
MSL Method
MSL Method
Kumazoe River
Pre-treatment System
Administration building
Sluice
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Kumazoe River purification facilities (the MSL method)
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The demonstration experiment of pilot scale on the site for Kumazoe River purification project
MSL method Permeable layer
Soil mixture layer
Pre-treatment system MSL method
Kumazoe River Onga R
iver
Water-intake discharge
discharge
Pre-treatment
system MSL method
Water quantity for treatment 144m3day-1(4m3m-2day-1)
(Loading rate) Pre-treatment system 72m3day-1× 2
The MSL method 48m3day-1× 3
The scale of the system
Water-intake
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0
20
40
60
80
100
120
12 1 2 3 4 5 6 7 8 9 10 11
MONTH
ＢＯＤ
( mg
L -1
)
river water
treated water(MSL1)
treated water(MSL2)
treated water(MSL3)
A performance of demonstration experiment
2,000 2,001
Seasonal change of BOD concentration in the demonstration experiment
source: survey by Ministry of Land, Infrastructure and Transport
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0
20
40
60
80
100
120
4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00 2:00 4:00
TIME
BO
D(m
gL
-1）
river water
treated water(MSL1)
treated water(MSL2)
treated water(MSL3)
May 18,2001
Dairy change of BOD concentration in the demonstration experiment
source: survey by Ministry of Land, Infrastructure and Transport
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The comparison of performance and cost
MSL system contact oxidation
system by gravel
with aeration
contact oxidation system
by gravel and various
types of plastic modules
with aeration
advanced contact
oxidation system by
gravel with aeration
BOD of influent water ( mgL - 1
) 55 55 55 55
BOD of effluent water ( mgL - 1
) 5 14 10 10
site area (m 2 ) 2,300 2,400 1,200 1,000
construction cost ( million yen ) 440 512 1,031 440
maintenance cost ( thousand yen ) 6,000 6,600 18,000 6,000
Source: The above construction cost are used as an example, and so are difficult to the real cost.
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The construction processes of the MSL method
In making of the soil mixture layers, a nonwoven fabric
was laid in the plastic cage and the mixed soil was filled
up in it.
These blocks were laid like left picture.
The void spaces (permeable layers) between each block and
block sides were filled with pumice.
The inlet pipe was installed at the top of the system.
Soil is covered on the surface of the system.
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reference data
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1000
1000 2000
mm
2500
1000
1000
1200
4000
3500
mm 1750
900
850
Wastewater
inflow Treated
water
outflow
Air
Air
Aeration
A
B1
B2
Perspective figure
Structure of Multi Soil Layering Method
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Cross Section
Aeration pipe
100
100
100
100
100
100
100
150
50
50
50
50
50
50
50
1200
mm
100 600
mm
Masa soil
Plastic net
Gravel 40mm
Porous pipe VU75mm
Drainage pipe Ceramic cups
for collection
of soil solution
Soil, Jutepellet, Iron Mixture
Jute net
Zeolite 1-3mm
Plastic net
Gravel 40mm
Vinyl sheet
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0
20
40
60
80
100
120
140
160
180
200
10:00 14:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00 6:00 7:00 8:00
Daily fluctuation of waste and treated water（1991/2/13-14）
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
inflow (L)
WW BOD
WW T-N
TW BOD
TW T-N
WW PO4-P
TW PO4-P
left axis
right axis
(mgL-1) (mgL-1)
Evaluation of system performance during the 10years operation
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0
20
40
60
80
100
120
140
160
180
200
7:00 8:00 9:00 10:00 13:00 16:00 19:00 20:00 21:00 22:00
Daily fluctuation of waste and treated water（1999/12/22）
0
2
4
6
8
10
12
14
WW BOD WW T-N
TW BOD TW T-N
WW PO4-P TW PO4-P
left axis
right axis
(mg/L-1) (mg/L-1)
Evaluation of system performance during the 10years operation
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Soil unit
High
treatment
efficiency
High loading rate
(less clogging)
Toilet, Restaurant ww treatment Advanced treatment of
sewage or domestic ww
Direct treatment of
polluted river water
Thick ness
Width
Heavily polluted water
Low loading rate
Less polluted water
High loading rate
Moderately polluted water
High loading rate
Unit size is decided depending on
the degree of treatment needed.
MSL structure and type of water treatment
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Prevention mechanisms of clogging and shortcut in the MSL method
(1)Water flow in soil (2)Water flow in the MSL method
Clogging
Improvement of contact efficiency and filtration function
↓
Improvement of PO4-P，COD，SS removal
(3)Difference of water flows
by various materials
(a) Shortcut
(c) Prevention effect by MSL method
(b) Clogging
Lack of uniformity
