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What is essential for the
decentralized waste water
management ?
– Experience of Japan, Malaysia, India –
April 2, 2015
Kazushi HASHIMOTO
Adviser
Japan Sanitation Consortium
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Decentralized Wastewater Treatment System
(DEWATS) ①
• Septic Tank
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Decentralized Wastewater Treatment System
(DEWATS) ②
• BORDA DEWATS
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Decentralized Wastewater Treatment System
(DEWATS) ③
• Packaged Aerated Wastewater Treatment Plant
(PAWTP – Johkasou in Japan)
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Comparison of DEWATS
Septic Tank
BORDA DEWATS
PAWTP
(Johkasou)
Treatment
Process
Anaerobic
(Electricity not
required)
Anaerobic
(Electricity not
required)
Aerobic
(Electricity
required)
Effluent Water
Quality (BOD)
100-200 mg/l
50 mg/l
20 mg/l
Nitrogen
removal
Not removed
Not removed
Removed
US$ 80-150
US$ 90-100
US$ 210-380
CAPEX per
person in
developing
countries
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What happens, if DEWATS is not regularly desludged?
Any wastewater treatment system ceases to treat and
becomes a pollution source.
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What happens, if Septic Tank is not regularly
desludged ? ①
If the septage volume exceeds one-third the capacity of the tank, solid-liquid
separation decreases since the retention time of the wastewater decreases.
BOD removal is hampered since the inflow of wastewater agitates the
accumulated sludge causing inflow wastewater to pass through the tank
without treatment. Moreover, a part of the accumulated sludge in the tank
flows out together with the untreated wastewater, leading to further
deterioration in the water quality of the effluent of the septic tank.
(Source : USAID)
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What happens, if Septic Tank is not regularly
desludged ? ②
No septic tank meets the effluent standard established by the
Governor of Jakarta City Government for household septic tank
(BOD75mg/l, COD100 mg/l). Irregular desludging may be one of
the causes.
Volume
Usage
(persons)
(㎥)
Black
water
only type 1
Black
water
only type 2
Black
water
only type 3
Black & Grey
type – 1
Black & Grey
type – 2
Black & Grey
type – 3
(Source : JICA)
Effluent water quality
BOD
COD
mg/l
mg/l
145
421
6.0
15
2.2
4
231
622
2.9
4
217
544
7.4
4
206
419
10.0
40
162
367
10.0
18
213
401
Remarks
Desludged once
a year.
Desludged
twice a year.
Never
desludged.
Not desludged
(4 years)
Not desludged
(3 years)
Not desludged
(3 years)
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What happens, if PAWTP (Johkasou) is not regularly
desludged ? ①
Sludge accumulates quickly in a PAWTP since its wastewater
treatment efficiency is high. It must be desludged once a year to
maintain its performance standard.
After one year
After three years
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What happens, if PAWTP (Johkasou) is not regularly
desludged ? ②
A research, conducted in 1984 for 70 PAWTPs (black water
only type) in Japan, revealed that 24.6% of them had not
been desludged for more than 1 year, and their average
effluent water quality (BOD) was worse than the ones which
had been desludged with less than 1 year intervals.
160
140
120
100
BOD
80
COD
60
SS
40
NH4-N
NO2,3-N
20
0
<6 Month
6-12Month
12-18Month
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BORDA DEWATS
I wonder how to desludge this system ??
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What is essential for the decentralized wastewater
management ?
• Introduction of regular desludging system.
• Proper disposal of the sludge removed from
DEWATS.
Septage Management !
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What is essential for the introduction of regular
desludging system ?
• Desludging must be the legal obligation of all the owners
of any DEWATS.
• There must be the trained good desludging operators.
Formalize them, if there are existing desludging operators.
Let them make companies. Establish the licensing system
and training system.
• Data base of all DEWATS in the City. Both the municipality
and the desludging operators should have it.
• Use vacuum truck for the more efficient and hygienically
safer de-sludging operation.
• Use the sludge relay tank to shorten hauling time.
• Improve the DEWATS for the efficient desludging.
Necessity of Regulatory Framework for Septage
Management
Residents do not worry about the septic tank unless it
becomes full of sludge, overflow and their toilet becomes
unusable. Communication strategy is necessary but not
enough. Regulation is necessary.
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For good Septage Management, these peoples are the
most important !!!
Existing desludging operators in
Mizoram State, India, who are
conducting desludging of septic
tanks using a pump and a water
tank mounted on a truck.
PAWTP De-sludging Technician
PAWTP Inspector
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Economics of Regular Desludging
• The most expensive item for septage management is not the
DEWATS itself but the cost for desludging. Desludging of one
septic tank (3 ㎥) costs US$30 in Jakarta, US$50 in India,
US$70 in Malaysia, US$250 in Japan.
• In Japan, the desludging is considered not a profitable
business unless at least 4 PAWTPs can be desludged by one
vacuum truck. Efficiency matters.
• In Japan, many desludging operators cover 7 PAWTPs daily
and make money.
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Technology for the efficient Septage Management ①
Use of Vacuum Truck will ensure the efficient and hygienically
safe desludging operation.
Vacuum Truck
Time
Septic tank (3㎥) –
required for 40 minutes
PAWTP (5PE)
emptying
– 30 minutes
Discharge
10 minutes
of the
－Quick because
the caliber of the
sludge
hose is bigger (4565mm)
Possibility
None
of the
human
contact
with the
pathogen
Truck + pump
Septic tank (3㎥)－2
hours
These vacuum trucks shall
be leased to the existing
desludging operators.
30 minutes
－Slow because the
caliber of the hose
is smaller (32mm)
Possible at the time
of connecting and
disconnecting the
hose to the tank.
(Photo taken in Mizoram State,
India)
Technology for the efficient Septage Management ②
Sludge relay tank
will improve the
efficiency of
desludging
operation by
shortening the
hauling time.
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DEWATS must be desludging friendly
• It must be reachable for the desludging operators.
(1) It must be installed in the open air space.
(2) It must have manholes.
• It would be the most convenient if the partial
desludging could effectively remove all the sludge
without removing the water contents.
In case of septic tank, you need to remove all the
contents of the tank.
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In case of PAWTP, the partial desludging effectively
removes all the sludge. The water contents of the tank
does not need to be removed.
Proper disposal of the sludge removed from DEWATS
(1) Local municipality’s obligation to develop septage/sludge
treatment facility. Central government’s obligation to
provide financial support to Local municipalities.
(2) Sludge drying bed is an appropriate method if land is
available.
(3) If there is a Sewage Treatment Plant (STP) nearby, cotreatment at the excess sludge treatment section of a
sewage treatment plant is the best option. Proper pretreatment facility is required to minimize the adverse
effect on the operation of STP.
(4) Independent septage/sludge treatment facilities - In Japan,
there are 1,100 independent night soil/sludge treatment
plants of various technologies.
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Warning !
Establishing a workable Septage Management may
be the most difficult development agenda.
Only two countries have a nation wide Septage
Management System.
• Japan
• Malaysia (partial success)
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Septage Management System based on PAWTP
(Johkasou) Technology in Japan
In Japan, PAWTPs (black water only type) had been widely
difused since 1960s. In 1970s – 1980s, water pollution of rivers
and oceans had become a big issue. Particularly, the cause of
eutrophication occurred in lakes and inland bays was
attributed to the poor performance and maintenance of
PAWTPs (black water only type).
Only after the promulgation of PAWTP (Johkasou) Act in
1983, the maintenance of PAWTPs in Japan improved and
eutrophication of lakes and inland bays in Japan stopped.
The new installation of PAWTP (black water only type) was
banned and PAWTP (both black water and grey water type)
has become the standard DEWATS in Japan.
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Main points in the PAWTP Act (1983) (1)
Item
What does the PAWTP Act stipulate?
Manufacturing
and Installation
of PAWTPs
The PAWTP (black + gray water type) is the standard on-site
wastewater treatment facility in Japan. PAWTPs shall meet the
technical standards for effluent water quality and the structural
standards prescribed in the Building Standard Law.
Maintenance of
PAWTPs
The owner of a PAWTP is designated as the ‘PAWTP Manager’ who
is legally responsible for the maintenance of the PAWTP. The
PAWTP Manager shall make the PAWTP receive inspection,
maintenance and desludging. The PAWTP Manager can outsource
the work related to PAWTP management to a PAWTP vendor
and/or a PAWTP desludging vendor.
Desludging of
PAWTPs
The PAWTP Manager shall ensure that the PAWTP receives
desludging service once a year.
Inspection of
PAWTPs
The PAWTP Manager shall make the PAWTP receive an inspection
for its water quality annually by the Specified Inspection Agency.
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Main points in the PAWTP Act (1983) (2)
Item
What does the PAWTP Act stipulate?
Desludging
Business
A corporate body that intends to join the PAWTP desludging
business shall get the approval from the mayor of the municipality
for a limited period. The applicants need to conform to the
standards for approval stipulated in the PAWTP Law.
Maintenance
Business
A corporate body that intends to join the PAWTP maintenance
business shall register to the municipality concerned. The PAWTP
maintenance vendor shall assign its staff qualified as ‘PAWTP
Operator’ who has passed a national examination or completed a
training course conducted by a designated training agency, to the
PAWTP maintenance work.
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Number of people engaged in the Septage
Management Business in Japan
People with qualification
(Number of registrants)
Number of vendors
PAWTP
Operators
72,521 Operation and
maintenance
PAWTP
Installation
Workers
83,205 Installation/
Construction
Specified
inspection
agencies
65 PAWTP inspection
and water quality
examination
PAWTP
manufacturers
PAWTP
Technical
Supervisors
26,658 Management of
PAWTP with 501
PE or more
27 Research,
development and
manufacture
PAWTP
Desludging
Technicians
15,117 Desludging
PAWTP
Inspectors
Total
1,210
198,711
PAWTP
maintenance
vendors
12,871 Operation and
maintenance
PAWTP
desludging
vendors
5,375 Desludging
PAWTP
installation
vendors
33,593 Installation/
construction
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Malaysia’s effort toward establishing effective
Septage Management System ①
In 1993, Sewerage Services Act (SSA) federalized the sewerage assets, thus
empowering the Malaysian Government to regulate this industry. SSA also
provided the fundamental policies for septage management.
In 1994, Indah Water Konsortium (IWK) was created as the private
concessionaire who was responsible for O/M of all sewerage facilities, and
septage management. By these reforms,
・Sewerage coverage ratio : 25% (1993) ⇒ 70% (current)
・Desludging coverage ratio : 1% (1993) ⇒ 12.4% (1999)
On the other hand, the newly introduced sewerage charges (including
desludging charges) for individuals and businesses caused complains from the
Malaysian population and refusal to pay. As a result, tariffs were reduced at a
level too low to cover operation expenditures.
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Malaysia’s effort toward establishing effective Septage
Management System ②
In 2000, IWK was nationalized.
In 2006, SSA was replaced by the Water Service Industry Act
(WSIA). National Water Services Commission (SPAN) was created
to regulate water and sewerage services.
In the area of Septage Management, the IWK’s responsibility for
the desludging and maintenance of the individual septic tank was
transferred to the owner or residents of a premise, who are legally
responsible for engaging IWK (Service licensee) or a license permit
holder – both regulated by SPAN – to desludge and maintain their
septic tanks.
Fines up to US$ 15,000 was established against the noncompliance, which have not been imposed yet.
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Malaysia’s effort toward establishing effective
Septage Management System ③
The number of desludged septic tanks has substantially decreased since
2008.
No IST
70,000
IST DEMAND DESLUDGING
IST SCHEDULED DESLUDGING
No IST
60,000
450,000
400,000
50,000
350,000
40,000
300,000
250,000
30,000
200,000
150,000
20,000
100,000
10,000
50,000
0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Year
Total Attempted
0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Year
Total Unsuccessful
Total Desludged
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Malaysia’s effort toward establishing effective Septage
Management System ④
Desludging campaigns are being organized to incite septic tank
owners/users to desludge within the legal interval.
Jumlah
Septik
yang dinyahenap
cemar
No.Tangki
of IST
desludging
done
Desludging Campaign at:a) Taiping, Perak
b) Kangar, Perlis
c) Melaka
d) Yong Peng, Johor
e) Simpang Renggam, Johor
160,000
148208
146524
140,000
135982
No. of IST
120,000
100,000
80,000
68548
70170
60,000
58406
47056
40,000
37018
20,000
Desludging Campaign at:a) Muar, Johor
b) Temerloh, Pahang
c) Kubang Pasu, Kedah
d) Port Dickson, Negeri Sembilan
e) Sungai Besar, Selangor
0
2005
2006
2007
2008
2009
2010
2011
2012
Year
Malaysia’s effort toward establishing effective
Septage Management System ⑤
Ms. Y. B. Dato’ Noriah
Kasnon, Deputy Minister
for Energy, Green
Technology, and Water,
joined a desludging
campaign organized by
SPAN and IWK and
operated the lever of
vacuum track.
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Malaysia’s effort toward establishing effective Septage
Management System ⑥
Decrease of desludging activities has been affecting the river water quality.
RIVER WATER QUALITY BASED ON BIOLOGICAL OXYGEN DEMAND
Lessons from experiences of Japan and
Malaysia
• Any on-site wastewater treatment facility becomes
pollution source without proper Septage
Management.
• In order to do Septage Management, you must be real
serious. It is a highly political issue.
• In Septage Management, without proper regulation,
nobody does the right thing.
• In Septage Management, the people who do the actual
work are the most important. Regulate them. Formalize
them. Respect them.
• Septage Management will create a lot of job opportunities.
It is good for the economy at national and local levels.
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Thank you for your attention !
http://www.jsanic.org/
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