Community Based Sanitation (CBS) combined with Decentralized Waste Water Treatment Systems (DEWATS)
Angan As late as 2009, more than 90% Indian of domestic waste water was delivered to the environment without treatment and more than 50% of the Indian population lacked access to adequate sanitation facilities. In 2010, it was estimated that only 10% of Indian cities have a sewerage network and existing treatment systems only have the capacity to treat 21% of the wastewater generated. As part of the MDG’s (Millenium Development Goals), India strives to extend access to improved sanitation to at least half the urban population by 2015, and 100% access by 2025. This implies improving the availability and access of adequate sanitation facilities to households in order to rid cities of open defecation. Capacity building and training play a crucial role in sustaining 100% sanitation. Therefore, the IIYW initiated this project to implement “Community Based Sanitation Systems”, working with disadvantaged communities.


The Community based sanitation and slum development (CBS-SD) network partners are NGOS’s doing pioneering work in the development sector. They collaborate with each other to address issues of vulnerable and marginalized groups related to heath, sanitation and education.

The CBS-SD partners implement the sanitation projects using the CBS-SD approach which is an integrated approach to tackle the health and environmental conditions in poor communities, through awareness raising, education, and training. People-centered planning and people-centered management are key in the CBS programme. The beneficiary group, consisting of disadvantaged communities, is being involved through a participatory approach from the onset discussing their options for improved sanitation, thus developing the community’s ownership of the ‘Community Based Sanitation’ programme. CBS–SD includes the involvement of stakeholders, their problems, priorities and points of view in any planning process. In this process, the needs of the poor and especially that of marginalized groups are playing a key role.

IIYW’s CBS project is combined with Decentralized Waste Water Treatment Systems (DEWATS) in order to bring about sustainable change.


DEWATS (Decentralized Waste Water Treatment Systems) applications are designed to be low-maintenance: the most important parts of the system work without technical energy inputs and cannot be switched off intentionally. DEWATS applications provide state-of-the-art technology at affordable prices because all of the materials used for construction are locally available. Without considering facilities for necessary chemical pre-treatment of wastewater from industries, DEWATS applications are designed with four basic technical treatment modules which are combined and configured to provide a custom solution for a given sanitation/wastewater challenge:
  • 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.

Main DEWATS modules for physical and biological wastewater treatment:
1. Settler 2. Anaerobic Baffled Reactor 3. Anaerobic Filter 4. Planted Gravel Filter
The benefits of DEWATS:
  • Cost-efficient as no or only simplified underground sewer system needed (local, on-site treatment).
  • Low running cost and energy saving as no electrical devices needed for treatment.
  • Affordable as only locally available material required.
  • Minimal operation and maintenance (O&M) needs and cost, as minimal maintenance and human resource capacity levels needed.
  • Reliable, long lasting and tolerant to wide range of inflow fluctuations.
  • High variety of local water reuse options (e.g. irrigation, gardening etc.).
  • Easy and effective local energy recovery (e.g. biogas used as fuel or cooking, lighting).
  • High local reuse potential for nutrients/sludge (e.g. as natural fertilizer, soil conditioner).
  • Easily and quickly applicable in marginalized and unconnected areas (slum, outskirts).
  • Applicable on household, cluster and community level.

Community based sanitation and slum development (CBS-SD) India Programme aims at improving the living conditions of poor people in urban and peri-urban slums in Indian cities. The programme is marked by the implementation of community based sanitation (CBS) combined with Decentralized Waste Water Treatment Systems (DEWATS). On the social front, the programme initiates the self organization of the target community, thus building the communities capability to independently manage the improvement of living conditions in their own communities, emphasis on improving sanitation infrastructure and service delivery to make community health and open defecation free communities.

Improvement of public health and reduction of water source contamination:
  • Especially in low income areas.
  • Cooperation with local self-help groups, NGOs and decision makers at different levels
  • Holistic project approach
    • Establishment of self-help groups (SHG)
    • Participatory service provider models
    • Provision of health and hygiene behavioral change measures
    • Provision of customized, environmentally sound sanitation infrastructure
  • CBS-DEWATS is a socio-technical approach and applications are designed in a way that treated water meets standards stipulated by environmental laws and regulations. The combination of proven mechanical and biological treatment modules, allows efficient treatment of organically polluted wastewater. Key feature of DEWATS is its low level of O&M requirement.
ACTIVITIES 2012-2013

Kolhapur flagship project – social intervention for strengthening CBS committee

The IIYW team conducted two visits to Kolhapur from 30.10-04.11.2012 and 28.12-01.01.2013 in order to motivate the Community Based Organisation (CBO) in charge and to re-ignite the required CBS related activities.

Operation and maintenance training in Kalmeshwar municipal council

50 members of Kalmeshwar municipal council participated in the training on the 23rd May 2012 which educated them about DEWATS and its processes and clarified their role and responsibilities regarding the operation and maintenance of DEWATS in their community. All queries and doubts the members had previously held could be answered and dispel led.

Organizing and conducting 3 days training programme on ‘health-hygiene and sanitation’ at Lonara campus

A 3 day capacity building progamme was held at IIYW’s Lonara campus from 20-22.10.12. 20 women and adolescents from Community Life Centres participated in the training on ‘health-hygiene and sanitation’. The participants were enabled to act as ‘change agents’ for their respective CLCs in order to further spread the training’s message to the communities in which they work as facilitators and hygiene promoters.

Orientation programme on DEWATS for the CBS community at Pandharkawda, Yavatmal.

105 people from the local community and municipality participated in the programme which raised awareness about the importance of environment sanitation and good health and hygiene practices as well as educating participants about the operation and management of DEWATS.

Preparation of brown paper bags for site visits of IWA conference

During 5 days, 5 women’s self help group members and 7 IIYW staff prepared brown paper bags to be used at the IWA conference. In total, 186 paper bags were handed over to be used for serving breakfast to delegates during 3 separate site visits.

‘Maitree’ (=friendship) world environment day celebrations

In order to mark world environment day (5.06) IIYW organised the orientation programme ‘Maitree’ (=friendship). There were 40 participants, including IIYW staff as well as members from other community based organizations, who were educated about issues ranging from CBS DEWATS, over global warming, to ‘how to go green’.


Integrated sanitation programme at Kolhapur-by IIYW

IIYW-CDD along with Kolhapur Municipal Corporation has implemented 3 pilot projects in the city of Kolhapur, Maharashtra. CBS-SD programme at Rajendra Nagar and Salokhe Park integrated 5 components of sanitation at one place namely child friendly toilets, compost yard, adult toilets, DEWATS unit and oxygen park. Thus, a model GO-NGO CBO is adopted towards a sustainable sanitation option.

Trichy project

EXNORA International, Tamilnadu has implemented CBS SD DEWATS project in East Devdhanam in Trichy. East Devdhanam is a per urban slum with a migrant population of 2000 People of different ethnic groups. The plant whose design capacity is about 9 cum is operated and maintained by the trained members of local self help groups. The project is partly funded by BORDA and stakeholders like Gram Panchayat, District Municipal Commissioner and community. The usage of bio gas from DEWATS unit is helping SHGs for cooking purpose and adds on livelihood through a micro enterprise by SHG.

Ullalu Upanagara SWAS model

CDD–Bangalore in collaboration with Gram Swaraj Samittee and support of L and S Architects implemented this demo model of 2 CBS SD DEWATS units, which are operational at bus stand site and government school site. Each unit treats 11.5 cum per day and the project is serving a cluster of 15 households. The women Self help groups systematically manages and maintains the entire complex and reuse of bio gas as fuel for heating water for bathing purposes and lighting is also demonstrated. This Pay and Use SWAS model is operated and maintained by women members through corpus fund.

Roopa Nagar Case study at Mysore-by RLHP

In 2003, 80 families, previously living in Speech and Hearing slum, were relocated here. KSCB constructed 80 houses under Wambay scheme. With the support of City Corporation, Green Hotel and the community, household toilets were built and KSCB laid the UGD for the toilets. As there was no treatment system linking the toilets, people could not use the toilets. With a view to provide decentralized sanitation solutions to this community, RLHP in partnership with and support of BORDA-CDD, three stage DEWATS was constructed, and the same was commissioned in 2007. Since then, people use the toilets and maintain personal hygiene. The treatment plant also helps to protect soil and ground water from contamination. The sanitation committee of Roopanagar takes care of O&M and the families support O&M through monthly contribution.

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