Report of DEWATS Training
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Transcript of Report of DEWATS Training
Report of the overseas training program on
DEWATS
(Decentralized Wastewater Treatment Systems)
03-08 October 2010
Venue – Nagorkot, Nepal
Training Conducted by
ENPHO
Environment and Public Health Organization
Submitted to
Department of Local Government
Eastern Province
Sri Lanka
Prepared By- Eng.A.J.A.H.Jowsi , Municipal Engineer –Kalmunai Municipal Council
Acknowledgement
My Heartfelt Gratitude Goes to the UN-Habitat for sponsoring my training
program .I wish to express my special thanks to Dr. Fahmy Islmail ,National
Technical Advisor of UN-Habitat Sri Lanka for motivating me to participate in the
Training
Secondly I am very much thankful to Hon. Governor, The Chief Secretary and the
Commissioner of Local Government of Eastern Province for granting official duty
leave and to Hon.Mayor and Commissioner of Kalmunai Municipal council for
releasing me for the Training.
My Sincere thanks go to the Trainers, Mr. Rajesh Pai and Ms.Susmita Sinha , from
CDD , Mr. Bipin Dangol from ENPHO and my colleagues who supported and
contributed to successfully complete this valuable Training .
Contents
1.0 Background
2.0 Key Learning
3.0 Application of DEWATS in Local Sri Lankan Context
4.0 Recommendations
5.0 Annexes
01. Background
The training program was organized by ENPHO and Supported by various
organizations such as UN-HABITAT , CDD and BORDA . The title of the training
was “International Engineers’ Training on DEWATS”
Participants from countries from Nepal , India, Pakistan ,Bhutan , Malaysia and
Mongolia attended the training .
The training started on 03-10-2010 (Sunday) with the Introduction to Wastewater
Characteristics and Presentations by the participants on experience on Sanitation
Projects. On the second day onwards until the third day afternoon it continued to
cover design of the conveyance system and comparison in between centralized
systems and the de-centralized systems, subsequent to that design calculations
for different DEWATS modules were explained. On the third and fourth days a
concept designs was prepared for three cases. Participants were divided in to
three groups and three cases were considered to develop DEWATS. (Community
project, a Hotel and the training center) Field visits were performed and
presentations were made on the each group work. On the fifth day excursion
was made to sites, which are in operation and under construction . On the sixth
day; construction, commissioning, maintenance and monitoring aspects were
covered.
Brief Introduction about DEWATS
DEWATS stands for “Decentralized Wastewater Treatment Systems”. DEWATS is a
technical approach rather than merely a technology package.
DEWATS applications are based on the principle of low-maintenance since most
important parts of the system work without technical energy inputs and cannot
be switched off intentionally.
Main DEWATS modules for physical and biological wastewater
treatment:
1. Settler 2. Anaerobic Baffled Reactor 3. Anaerobic Filter 4. Planted
Gravel Filter
Advantages of DEWATS
Providing treatment for domestic and industrial wastewater
Low primary investment costs as no imports are needed
Efficient treatment for daily wastewater flows up to 1000m3
Modular design of all components
Tolerant towards inflow fluctuations
Reliable and long-lasting construction design
Expensive and sophisticated maintenance not required
Low maintenance costs
2.0 Key learning
Design of the Modules of the DEWATS
Design calculations were made individually then the results were
discussed and compared. Indian standards were used to calculate the
water demand, and other design parameters.
Construction and Maintenance aspects.
Techniques adopted for the construction of Bio-Gas reactors and
Planted Gravel Filters (PGF) were greatly discussed. Maintenance
aspects such as de-sludging , replacing the filter media at Anerobic
Filters and PGF were understood .
Concept design for community, hotel and Government Institutions
A concept design was prepared for the Hotel called “Hotel –Country
Villa “ as per my Group exercise. We made site inspection to collect
data and to Identify the issues .
We collected the relevant data such as Water usage , existing disposal
practices , future expansions of the hotel , the availability of the land
and the re-use options .
Group design exercise was done , a concept design for the Hotel was
prepared . There has been power point presentations made on each
concept design.
Field Visit to DEWATS under construction
ENPHO has designed a DEWATS for an orphanage in the vicinity of
Kathmandu. Practical aspects of construction of DEWATS was explained
at the site .
Field Visit to the Existing Systems
a. Site-1 . Community wastewater treatment
This project was funded by UN-Habitat and implemented by the
community based organization in Collaboration with the Municipality of
the area concerned . It is designed to cover 200 units , and at present
135 units have already been connected . The facility has been running
for one year .
Bio-gas produced at the treatment facility is supplied to 6 houses and
the income generated from that is used for the payment of the
caretaker of the treatment facility.
Treated effluent is discharged to the nearby stream , the samples at the
outlet were collected to ensure the BOD is within the limit.
b. Site-2 Community wastewater treatment
In this site , wastewater is flowing through a Settling tank and through
two PGFs , horizontal and vertical . A bio gas system is to be augmented
to the existing system and it was already constructed.
This treatment plant is working for four years ..the treated effluent is
allowed to flow through the drainage canal.
c. Site –c Eco-House .
One house belongs to one of the executive officer of ENPHO was visited
It has rainwater harvesting, Bio-gas using organic waste and Worm-
composting .
The house portrays and ideal model of ECO-house .
Interaction with counterpart engineers and sharing of the experience.
This training program enabled a sharing platform amongst the participants .
Group works , games in the training , Entertaining programs in the evenings
and visit to the sun-rise scene .
Experiences of various country situations were discussed . For example
about the Extreme cold weather conditions in Mongolia and the techniques
adopted .
3.0 Application of DEWATS in Srilanka context
Suitability of the DEWATS in Eastern Province
• DEWATS applications provide treatment for both, domestic and industrial sources
• DEWATS applications provide treatment for organic wastewater flows from 1-1000 m3
per day
• DEWATS applications are reliable, long lasting and tolerant towards inflow fluctuation
• DEWATS applications do not need sophisticated maintenance
Without considering facilities for necessary chemical pre-treatment of wastewater from
industries, DEWATS applications are based on four basic technical treatment
Modules which are combined according to demand:
• Primary treatment: sedimentation and floatation
• Secondary anaerobic treatment in fixed-bed reactors: baffled upstream reactors or anaerobic
filters
• Tertiary aerobic treatment in sub-surface flow filters
• Tertiary aerobic treatment in polishing ponds
DEWATS applications are designed and dimensioned in such a way that treated water meets
requirements stipulated in environmental laws and regulations.
Some Benefits
Bio-gas can be generated and it can be utilized to cover some portion of
operations cost .
Treated water can be re-used , the systems can be designed to get the Quality of
the treated for the different applications such as irrigation , toilet flushing ect.
Apart from it there some other benefits ,
� Ecologically Balanced – It helps in bringing tourists more and hence helps
more earnings
� Environment improved
� Social Encouragement
� Water sources are protecte
Potential areas to Implement DEWATS in Kalmunai
1.0 Tsunami Housing schemes – There are three major housing schemes in
Sainthamaruthu, Kalmunai Kudy and Maruthamunai which were constructed
on the reclaimed land. In these area there is a need to construct the
wastewater collection system as the infiltration of the soil is very low. During
the rainy seasons ground water rises to the surface level and making a
greater discomfort.
2.0 Hospitals - AMH hospital already has the wastewater treatment facility in
place. In future Sainthamaruthu and Maruthamunai Hospitals are to be
provided with proper wastewater disposal .
3.0 Commercial institutions. Hotels , factories discharge wastewater to ground or
water resources this must be stopped .
4.0 City Residential area – In the long term run .the entire city of Kalmunai need
sewer system .specially the Sainthamaruthu and Kalmunaikudy area need
within 2-5 years .
Constraints ( as specific to Kalmunai MC in applying DEWATS)
• Need significantly large area for the Planted Gravel filters .
• Flat land feature – need to pump the water , which may need additional
Operational cost . A service charge is to be collected from the community.
4.0 Recommendations
Community Consultation Programs
It is important build consensus on Wastewater treatment based on decentralized
options , support of the community is vital in the following aspects .
a. Cost of Operation and Maintenance of the system is to be covered from
the community . House hold fee for service is to be introduced . The cost
will be high if it is difficult to maintain the gravity flow so pumping is most
the significant part of the operation .
b. At certain location pipes and the necessary structures such as manholes to
be constructed in the properties as per the design.
Planning and Implementing wastewater management schemes
Employing professionals to study and propose DEWATS OPTIONS for the city (As
the apprentice for my professional review under the IESL ( Institute Of Engineers
Sri Lanka ) , I wish to work on the design of the DEWATS System under the ISESL
recommended mentor. )
Preparing the proposal and seeking financial assistance.
City Development plan
It is important to know the population characteristics of the city , Population
density , Zones of development or Land use plan , to be prepared in
collaboration with the UDA.
5.0 Annexes .
1.0 Certificate of Training
2.0 Pictures