Prepared by Freya Mills, Yasoda Shrestha and Luna Kansakar for Conference on DEWATS for Urban Environments in Asia, 25-28 May 2011 Crowne Plaza Galleria, Manila Philippines.

1. Community managed DEWATS in Nepal
Freya Millsa,b, Yasoda Shresthab and Luna Kansakarb
a
GHD, 180 Lonsdale St, Melbourne, Australia, and ENPHO
(Email: freya_mills@yahoo.com.au)
b
Environment and Public Health Organisation (ENPHO), P.O.Box - 4102 Kathmandu Nepal,
(Email: yasoda.shrestha@enpho.org, luna.kansakar@enpho.org)
Abstract
The cluster and peripheral communities in the Kathmandu Valley are well suited to the decentralised
wastewater system (DEWATS) approach; however a lack of research or promotion of their
performance and sustainability has limited their wider uptake and adoption. This study assessed four
community managed DEWATS in Nepal to identify the treatment methods, management frameworks
and funding mechanisms which can lead to sustainable operation and good performance. The
assessment highlighted the benefits of setting up a strong community wastewater committee and
involving residents in the construction phase, which led to ownership, understanding of operation and
responsibility for maintenance. Additionally there are great benefits from biogas generation in
creating financial stability and a demand for good performance. Challenges exist in maintaining
motivation when there is no material incentive or funding, therefore promoting the use of by-products
is important. Overall, most community committees were motivated for and proud of their systems,
thus facilitating long term sustainability.
Keywords
Wastewater treatment; DEWATS; Community; Nepal;
INTRODUCTION
The urban population in the Kathmandu Valley is growing rapidly. Although large numbers
are moving into the densely populated cities of Kathmandu, Patan and Bhaktapur, the number
and size of cluster and peri-urban communities are also growing. These communities often
lack basic services and are generally considered a lower priority for upgrading services
compared with urban centres. The current state of wastewater treatment in the Valley is very
poor with only one operational centralised treatment plant treating less than 5% of a
population of approximately 2.6million (GHD 2010). The remainder connect illegally to
stormwater drains, discharge directly into waterways or discharge into the ground via poorly
operating septic tanks, all contributing to the poor health and quality of waterways and
groundwater. Additionally, the wastewater master-plan indicates that widespread centralised
sewage treatment is a long way off due to challenges in land availability, plant selection,
operational capability and conveyance systems (GHD 2010). With the priority to treat the
dense urban areas, the connection of peripheral communities to a centralised wastewater
treatment scheme is many years off.
Decentralised Wastewater Treatment Systems (DEWATS) appear well suited to these peri-
urban and cluster communities due to the low skills required to operate, use of local
materials, no need for the limited available power, and potential demand for treatment by-
products near to the waste source. With a DEWATS it is also possible to decentralise
responsibility of service delivery and management away from the government to the users,
which is often more successful as they receive the service benefits and by-products, are
impacted when the service fails and can more rapidly respond to problems than a large
1

2. government managed approach. However, as with any community managed system, there are
the challenges of ownership, responsibility, maintenance and funding, and despite DEWATS
being low maintenance, some ongoing work is required to achieve long term good
performance.
Determining which systems are best suited to the community-managed approach to improve
ease and reduce cost of operation and maintenance is integral to ensuring high performing
system over a long life span. The best approaches to community education on wastewater
issues prior to installation and the management and funding structures set up post installation
for operation, both need to be determined relevant to the community-managed situation. This
study aims to assess the operation of four existing plants in Kathmandu Valley to gain
confidence in the community management of DEWATS and understand the best approach to
adopt. Since there is currently limited data or knowledge about these systems and their
ongoing performance, there is hesitation by the government, private, and aid sectors to
promote them further. Through understanding the current performance of the systems,
investigating design and management issues and determining a suitable model for DWEATS
in communities in Nepal, greater confidence will support wider scale adoption and
implementation of sustainable systems.
METHOD
There are currently four operational community managed decentralised wastewater treatment
systems in Kathmandu initiated by the Nepali NGOs ENPHO and Lumanti, with assistance
from ADB, Water Aid, UN Habitat and local municipalities. The community systems
assessed were all treating greater than 30 households with shared responsibility within the
community for the operation, maintenance, management and funding. The systems were
constructed between 2006 and 2008 and have not been assessed as a whole, nor have
additional community systems been built since then. This assessment included a survey of the
implementing organisation, an assessment of the wastewater treatment system including
performance if sufficiently operational, and a discussion with community members and
caretakers about their perceptions of the system and any issues they are experiencing. Table 1
is a summary of the systems assessed.
2

3. Table 1 – Summary of Community DEWATS in Nepal
Sunga Community, Thimi Srikhandapur
Year Built: 2006 Year Built: 2006
Funder: UN habitat, Water Aid, ADB Funder: Dhulikhel Municipality, UNHabitat
Size: 200hh design current 85hh Size: Designed for 200 hh, currently 125hh
System: Biogas, ABR, 2xHFW, 2xVFW, SDB System: 2x Biogas, 6xwetland,
Cost: 22-32 lakhs (USD$30-44,000) Cost: 53 lakhs (USD$72,000)
Performance: very high BOD loading, high sludge Performance: very good performance, although
build up in ABR, poor maintenance, blocked stormwater infiltration high
BOD In:1250mg/L COD In:4032mg/L BOD In:90mg/L COD In:406mg/L
BOD Out:70mg/L COD Out:272mg/L BOD Out:15mg/L COD Out:210mg/L
Operation/Maintenance: Employed maintenance Operation/Maintenance: User committee manages
staff, community committee the O&M. There is a part time caretaker
Funding: Caretaker funded by municipality. Sunga Funding: Part time caretaker paid 1500/mth with
WWTP Management proceeds from Biogas. Users Committee not paid.
Reuse: Biogas sometimes produced to school. Reuse: Biogas reuse very good. No sludge or water
Discharge to irrigation channel mixed with polluted reuse. More houses could to connect to Biogas.
water
Sano Khokana Kiritpur
Year Built: 2006 Year Built: 2006
Funder: Lumanti, UN Habitat Funder: Lumanti, WaterAid,
Size: 37 hh Size: 30hh
System: Biogas, Settler, Sludge pits, Wetland, Pond System: Baffled settler, 2 HFW
Cost: 27 lakhs (USD$37,000) Cost: 9Lakhs, (USD1200)
Performance: Poor operation due to no maintenance Performance: System is not performing well,
staff but good biogas supply. blockage in pipes, broken inlet and no outflow
Operation/Maintenance: Community owned and Operation/Maintenance: Community are responsible
managed. Looking for new caretaker. Women’s for O&M but are generally not.
savings & credit group to take over management. Funding: Community meant to be saving 10Rs/mth
Funding: Caretaker fee was 1500/mth funded from towards O&M but are not; instead expect Lumanti to
biogas (3/5 pay 250/mth), each house pays 30Rd/mth pay salary (3000/mth expected).
& any visitors (500/visit) Reuse: When operating the community reuse treated
Reuse: Biogas reuse by 4-5hh. Slurry and compost pits water for gardening but currently insufficient flow.
for fertilizer but not fully dried & re-used.
3

4. RESULTS & DISCUSSION
Project Need and Initiation
The motivation and understanding of the communities’ need for a wastewater treatment
system is integral to long term operation and the ongoing commitment of community
members. The community project at Sunga was moved from a previously identified
community in Sidhikali that could not achieve consensus on installation and location of a
WWTP. The Sunga community approached ENPHO for the installation of the plant with the
motivation of rehabilitating the dump site and subsiding cliff area of the WWTP site, and to
protect the downstream river from contamination. At Sano Khokana the community was not
using their pit latrines in favour of open defecation because the latrines were expected to fill
up too quickly and the removal costs are too high. However, through WATSAN education
campaigns they understood the need for sanitation and were eager for a solution and selected
the biogas plant. The community members at Kiritpur were being charged by a downstream
landowner for their wastewater discharge on his site, and therefore installed the DEWATS
and no longer have to pay. At Srikhandapur the municipality identified three suitable sites
based on existing infrastructure and layout, and fortunately, the chosen community was
highly motivated once the plant was proposed. All projects included involvement of the
community in selection of treatment option, participation and contribution to construction and
some operation training which has assisted in ownership and understanding of the system.
DEWATS Design and Suitability
Although most DEWATS are simple to operate, the selection of which systems and the finer
design details influence the ease of operation and long term performance. Table 2 is a
summary of the different DEWATS components at each site and the advantages and
disadvantages of the installed designs relevant to the site and the operational skills.
Table 2. DEWATS Design Benefits & Disadvantages
Benefits Disadvantages
Sunga ABR, Multiple treatment systems Bar screen inlet is always blocked.
Biogas, are beneficial for the high Biogas wall is cracked due to poor
2x HFW, concentration inflow. The construction. The ABR size is too
2x VFW, system makes good use of small for the high concentration
SDB stepped land allowing for inflow requiring regular desludging.
VFW. Wetland distribution pipes broken/
blocked in both HFW and VFW.
Shrikhan 2x Very good supply from Too many HFWs to maintain. Pipes
-dapur Biogas, biogas, however as it is very from biogas to the HFWs not even
6x HFW large there is potential for causing uneven flow distribution.
more houses to be connected. Wetlands are possibly leaking since
Well designed inlet channel. discharge flow is very low.
Sano Biogas, Good biogas supply, even to Waste separation is labour intensive
Khokana ABR, houses far away. Holistic and the chopping of kitchen waste for
SDB, waste management approach. biogas is difficult due to broken
HFW, High reuse potential of grinders. The HFW is leaking into
Pond fertilizer and treated water. pond without treatment.
Kiritpur Settler, Simple system, reuse tank Septic tanks at each property poorly
2x HFW useful location for the designed or too small requiring
agriculture land downstream. frequent desludging. Manhole pits are
not clearly located.
4

5. Note: ABR–Anaerobic Baffle Reactor, HFW–Horizontal Flow Wetland, VFW–Vertical Flow
Wetland, SDB-Sludge Drying Bed
The long term success of a community DEWATS relies on suitable design and quality
construction to make the most of the initial available funding and limit the ongoing costs to
the community. Key design features that assist with sustainable operation in the systems
assessed in Kathmandu include:
• Simple processes to reduce daily maintenance or skills required – no grates, no
tipping buckets, long desludging period (large initial chamber), no pumps;
• Channel rather than pipe distribution inlets to wetlands;
• Including allowance or diversion for stormwater inflows;
• Access for sludge removal trucks and access openings on all chambers (able to be
lifted by one person);
• Good construction including water tight walls & floor, level pipes, sufficient
thickness brick and concrete walls, properly jointed pipes, buried pipes, correct levels;
• Inclusion of community in construction phase to understand system for maintenance;
• Create an income generating by-product such as biogas and allow for use of treated
water prior to discharge into channel.
Operation & Maintenance
Across the systems the operational ease of the plant was a main component in ensuring long
term performance and operation. At Sano Khokana the hands-on work required for waste
separation caused the previous caretaker to resign. The Sunga inlet has a bar screen which is
too small for the high solid content of the flow and is often blocked causing flow to divert
past the treatment system. Additionally, the multiple bypass options at Sunga are not used
correctly, due to the lack of understanding of the caretaker and ease of changing them,
causing frequent emptying of ABR and diversion of flows into open pit. At Kiritpur there has
been no maintenance since construction and poor understanding of operation which resulted
in the inlet pipe breaking; bed is covered in sludge, weeds and rubbish; and some walls have
collapsed. However these are minor issues which could be rectified easily and, with
community motivation, the plant could be operating well again. The potential issue of the
twice-daily need to open the biogas valve is actually beneficial since it ensures site
attendance daily and quick identification of problems. In general, regular cropping of the
vegetation or replanting was not occurring and the need or method for desludging was not
well understood. At Srikhandapur the sludge drying bed has not yet been used, at Sunga it is
overused and not able to dry, and in Sano Khokana the alternating of beds had not occurred
and rubbish was dumped in the pit. The involvement of the community in the construction
and provision of detailed initial, then regular ongoing training, is the best opportunity to
improve the communities’ understanding of the system and ability to maintain it.
DEWATS Performance
The wastewater quality of two systems was tested to determine the treatment efficiency and
the discharge against the required discharge quality for treatment systems in Nepal (MOPE,
2003). The wastewater was collected using grab sampling at Sunga and Srikhandapur and
tested in the ENPHO laboratory. These sites have also been tested in previous years and the
results could be compared with prior performance. As well as improving understanding of
current performance, the quality testing also aimed to determine an appropriate influent
quality standard for community wastewater in Kathmandu and actual treatment effectiveness
of each system. The other two sites did not have sufficient flow through the entire system to
test the quality, however, there is testing planned for 2011 after maintenance is undertaken.
5

6. Srikhandapur Influent/Effluent Sunga Influent/Effluent Load
600 5000
1304mg/L
Aug-09
500
Feb-10 4000 2006
400 Aug-10 2007
L3000
/ 2008
300 g
mg/L
m
2000
200
100 1000
0 0
Inflow BOD Inflow COD Outflow BOD Outflow COD BOD In COD In BOD Out COD Out
Figure 1 – Influent and Effluent Quality Srikhandapur Figure 2 – Influent and Effluent Quality Sunga
Srikhandapur Treatment Across System Sunga Treatment Across System
300 4000
3500 BOD
250 BOD
3000 COD
COD TSS
200 2500
TSS
150 2000
1500
100
1000
50 500
0 0
Inflow Biogas Out Wetland Out Inflow Out ABR Out HFW Out VFW
Figure 3 – Quality across system Srikhandapur (2010) Figure 4 – Quality across system Sunga (2010)
Srikhandapur Treatment Efficiency Sunga Treatment Plant Removal
100
100% Aug-10
Feb-10 t 90
90% n
a
l
Ave % Removal
Aug-09 P80
80% s
s
o
r 70
70% c
A
l
a60 2006
60% v
o 2007
m
50% e50
R 2010
40% % 40
30% 30
BOD COD TSS BOD COD TSS
Figure 5 – Performance Srikhandapur Figure 6 – Performance Sunga
The influent loads of Srikhandapur and Sunga are very different with Sunga continually
receiving influent BOD levels greater than 1000mg/L and Srikhandapur always below
100mg/L. Other old village sites have tested similar levels to Sunga with Shankamul
discharge quality of 1650mg/L, however other mixed sewers like Srikhandapur have similar
results of 410mg/L (Kirtipur Central Horticulture Centre). The very high concentration is
likely due to very low water use in these older towns where wells are the main supply and
water availability is low. The discharge effluent of Srikhandapur always meets the Nepali
discharge guidelines of 50mg/L BOD and 250mg/L COD (MOPE 2003), however the Sunga
site often discharges just above this level. The treatment efficiency at Sunga is very high,
indicating that the good treatment is occurring but the very high influent load causes the
discharge quality to not meet required level. The Srikhandapur treatment performance is
generally high, however a high COD load causes low removal performance, this high load
could be due to agricultural runoff entering the mixed sewer. It will be beneficial to compare
these results with Sano Khokana and Kiritpur when tested in 2011 to determine a suitable
influent loading to assume for community systems.
6

7. Management Frameworks
In decentralising the wastewater treatment process, the ownership and management is also
moved away from central government to community or partial municipal management. With
the low priority of wastewater treatment in Nepal to date, the poor performance of existing
plants and the long approval and construction process for new plants, there are many benefits
of the decentralised management approach. By shifting the responsibility to those using and
benefiting from the system, locating the plant in close proximity to its owners and having
some dependence on good performance (ie. biogas supply, reuse water, no odour) has shown
strong benefits in long term operation and response to issues. However, as with any shared
facility there is difficulty in assigning responsibility to its upkeep or ensuring ongoing
commitment from a group. It is the responsibility of the implementing organisation to
determine and set up a suitable management framework to allow for the ongoing
management and operation of they system.
Community user management groups, municipality and other community organisations are
key stakeholders in the operation of DEWATS, response to problems and gathering of funds.
An important component for Srikhandapur, Sunga and Kiritpur systems is the strong support
of the municipality in implementation and ongoing maintenance. At Srikhandapur the
municipality paid for the land, at Sunga the municipality pays for the caretaker salary and at
Kiritpur the municipality has subsidised septic tank pump out and provides waste
management services. A water user committee often exists in many communities or one can
be set up from the project outlay and has been successful in management of these systems. At
Sunga the wastewater committee collected funds and organised for the fixing of a wall
broken by landslide. At Srikhandapur the management committee, particularly the gas users,
are responsible for the operation, fixing gas blockages, collection of funds and paying the
caretaker. At Sano Khokana the user committee has collected funds, adds organic waste to
the biogas and turns the gas on/off whilst there is no caretaker. However at Kiritpur there is
no active group that takes responsibility for the DEWATS. This is highlighted in the fact that
they feel little responsibility for the system and do not maintain it. Over time the management
may need to change, particularly as water user committees dissolve and a more permanent
structure or financial management is required. At Sano Khokana, and potentially Kiritpur, the
Women’s Savings and Credit group is taking over the management and collection of funds,
with the benefit of having members from each household and already collecting savings
payments.
Funding Methods
The funding of operation and maintenance is a major challenge for DEWATS in Nepal, with
low priority to wastewater treatment, no charges for dumping waste without treatment and
generally low income in many small communities. However, most of these sites show that
good financing is possible when a method is set up at the project start. Both Srikhandapur and
Sano Khokana provide a steady income to pay a caretaker’s salary through the proceeds of
the biogas plant, with the Sano Khokana community also contributing 30 Rs per household
per month and also charging visitors to the plant. The Sunga caretaker is funded by the
municipality under an arrangement organised at the plant initiation as the municipality’s
contribution to the project. The Kiritpur site management was initially funded by the
contractor but, following completion, there was confusion regarding the responsibility for
ongoing funding and maintenance. The community expected Lumanti to pay the caretaker
salary as they were paying for the fines for discharging wastewater, whereas Lumanti
intended for the community to contribute 10Rs per month on top of their existing loan
repayments. However this is not occurring and motivation to pay for the wastewater is low
7

8. due to a general feeling that the system is not their responsibility, especially in households
which are struggling to meet their loan repayments. This highlights the need to ensure
community motivation and commitment, as well as setting up secure management and
funding mechanisms that are agreed to by the community, prior to the project. Despite most
systems sustaining the ongoing operational costs, there is generally no saving for major
maintenance activities such as desludging, pipe replacement or major repairs. Therefore it is
even more important to ensure that the initial construction and design is done to a high level
and to minimise the maintenance requirements.
CONCLUSION
The continued success of three of the four community treatment plants assessed gives
confidence in DEWATS as a sustainable solution to wastewater treatment in cluster
community and peri-urban areas of Nepal. Some important requirements of the project
initiator are to determine the suitability and commitment of a community to owning a
DEWATS; designing a suitable low operation treatment system; setting up a sustainable
management and funding framework and providing ongoing maintenance training. The
systems in which communities had a motivation for wastewater treatment, a proven ability to
manage a project together, and financial capacity for some contribution to the project, were
successful in operation and management. Additionally, a major opportunity for project
initiators and designers to ensure long term success of a community managed DEWATS, is to
select the most appropriate design, supervise quality construction and provide ongoing
operation training. Most community projects have more funding available at the start of the
project, therefore opportunities for the proposed design improvements that can increase the
lifespan of components, reduce O&M activities and costs, should be included.
Of the two systems assessed for wastewater quality, the Srikhandapur met the Nepal
Discharge Guidelines however the Sunga system just failed despite over 93% removal in
BOD5, COD and TSS levels. The ongoing removal performance of Sunga and Srikhandapur
has remained high over the years, and with minor maintenance works to improve flow
distribution at Srikhandapur and remove sludge at Sunga, they will continue to operate very
well in the future. Assisting ongoing performance was a stable management body which was
regularly undertook operation and maintenance activities, responded quickly to issues and
independently fixed problems. Wastewater user groups set up at the start of the project have
worked well, particularly when set up with a funding method and given training on operation
requirements. However, over time as their other responsibilities reduce, there is an
opportunity for the Women’s Saving and Credit groups, or similar bodies, to take over
management such as is proposed at Sano Khokana and in discussion at Kiritpur.
The generation and use of biogas is a very suitable inclusion into DEWATS in communities
as the payments for its use create a secure funding for the operation costs and a demand for
good performance. Although not currently used, other by-products such as fertilizer and
treated water also have good funding potential. Municipal support at the start of the project
and commitment to some ongoing funding is also a sustainable approach to funding
operation. Monthly payments by each household had lower long term success as wastewater
treatment in Nepal is not yet valued to the level of paying for the service. Due to the shared
nature of community systems, it is not expected or feasible for individuals to operate or
maintain them without some financial incentive. From this assessment it is evident that a
system should not be installed unless a suitable management and finance system is agreed
within the community and there is confidence that operation and maintenance will occur.
8

9. There will always be difficulty in motivating groups to install wastewater treatment systems
and manage or fund their operation whilst there is no regulation for wastewater discharge in
Nepal. However, with an increasing promotion of the impacts of poor sanitation and the long
time before any major centralised system will occur, there is great potential to encourage
more communities to adopt this approach. Community motivation is the main driver in
getting a project initiated, ensuring operation and ongoing maintenance and contributing
funds. Through the promotion of these treatment systems and other DEWATS in Nepal, it is
expected the interest from both communities and donors to implement these systems will
increase. As ENPHO and other organisations undertake wide scale sanitation projects, it is
recommended to include an assessment of the potential and benefits of DEWATS in
comparison with individual on site options (ie. eco-san toilets). Additionally further
regulation and education against untreated wastewater discharge would assist in communities
understanding the need for DEWATS or desire to make a difference. Within a sound
management framework and with a well designed system, there is strong evidence that
community managed DEWATS can be sustainable and are a suitable method for wastewater
treatment in Nepal.
REFERENCE
GHD, (2010) Conceptual Wastewater Master Plan, Final Report, report prepared for Asia
Development Bank as part of Kathmandu Valley Water Supply and Wastewater System
Improvement TA4893-NEP by GHD, in association with ICON Consultants Ltd,
February 2010
Lumanti (2008), Cleaner Communities Newsletter, Nepal, viewed 9 January 2011,
< http://www.lumanti.com.np/downloads/Newsletter.pdf
Nepal Ministry of Population and Environment (MOPE), (2003), Wastewater Discharge
Guideline, June 2003.
Rajbhandari, K (2009) Kirtipur Housing Project Report, WaterAid Nepal.
Sasse, L (1998) Decentralised Wastewater Treatment in Developing Countries, BORDA,
Delhi
Tuladhar, B., Shrestha, P. and Shrestha, R. (2008) ‘Decentralised wastewater management
using constructed wetlands’, Proceedings of Beyond construction: Use by all workshop,
Water Aid and IRC International Water and Sanitation Centre, Rajendrapur, Bangladesh,
pp 86-94
Water Aid, (2008) Decentralised wastewater management using constructed wetlands in
Nepal, WaterAid Nepal
9