Four-in-ten people live in hazardous conditions due to poor sanitation. Indeed, with half the population of developing regions without sanitation, United Nations goals of halving, by 2015, the proportion of people without access to safe water and basic sanitation seem set to be missed.

The focus of this project is the 'peri-urban' environment, which includes areas outside cities that are characterized by poor infrastructure, and poor access to formal water and sanitation services. Here, people endure water contamination, ill-health, and lack of dignity.

Despite intentions to safely contain waste, sanitation systems such as pit latrines end up as "holes in the ground". Initiatives, such as 'Community-Led Total Sanitation' (CLTS), have emerged to tackle the challenge. It encourages communities to analyse their own sanitation situation and build low-cost toilets. One of the key lessons is that sanitation is a social as well as technical challenge.

In light of this, we comprise a team of natural and social scientists, which has come together to address this pressing problem by pooling our talents, interests and expertise. We believe that a "socio-technical" approach is required to help to quickly address this problem, and that only a mixed team of different experts can do that.

The proposed technology is based on anaerobic digestion (AD), which is the breakdown of organic matter by bacteria to methane-containing biogas, in the absence of oxygen. AD is a natural process, which occurs in soils, swamps and bogs. However, if applied in airtight tanks, AD can be used to treat wastes. AD is an established technology, particularly for the treatment of industrial wastewaters.

The AD process relies of several groups of bacteria working together in a cooperative manner to break down waste. Typically, the first group breaks down large chemical molecules (like fats and carbohydrates) to simpler molecules. Another group then continues the digestion process to yet-simpler forms of the waste, until eventually the methane-makers convert the waste to biogas. The groups live very closely together in slimy communities, known as biofilms. The type of biofilms commonly found in wastewater treatment tanks are known as 'sludge granules', due to their spherical appearance. The diameter of each granule is approximately 1 mm. Each granule contains millions of bacteria and, theoretically, all of the different groups required to digest the waste will be present in each single granule.

AD has many advantages over more conventional types of wastewater treatment, which are carried out in aerated tanks. The chief advantage is that AD is cheaper, as there is no need to waste energy on pumping oxygen into the AD tanks. In addition, the biogas produced by AD can be readily used for electricity generation, heat production or as a vehicle fuel. It is likely that future wastewater treatment infrastructure in the UK will rely on AD for these reasons.

Thus, the objective of this project is to develop a low-cost system, based on AD, for the safe and efficient treatment of domestic wastewater (sewage and personal washing water). The system will convert waste to biogas and valuable products, such as fertilisers.

The challenges facing the team are two-fold:

(1) The sanitation system in the peri-urban environment is not based on a formal sewerage network of pipes with sewage transported by flushing water. Instead, a high-solids waste will be present. A major challenge will be to 're-engineer' granules to efficiently - and quickly - digest high-solids wastewater.

(2) There may be cultural and social issues impeding initial progress. The proposed system, and the way it might be used, may not be acceptable to local people.

We will engage with local people and integrate the social science required, with the engineering and science involved. In this way, a 'user-centred' prototype can be developed.

Potential Impact:
This will be a high-impact project with respect not just to academic impact, and the science and engineering underpinning it, but also with respect to a range of stakeholders. These include sanitation practitioners, policy makers, local administrators and the residents at the peri-urban interface.

The success of participatory techniques to encourage communities to analyse their own sanitation situation, stop open defecation and build low-cost toilets, as is promoted by the CLTS movement, indicates the centrality of stakeholder-engagement - and empowerment - to achieving positive changes in the lives of peri-urban dwellers. Our integrated project involving community and stakeholder engagement, fact-finding and analysis, and a methodological process of product conception, design and development, resulting in the implementation of our findings and the development of a prototype high-rate, eco-engineered, anaerobic digester for high-solids sewage conversion will have a major, far-reaching and transformational impact on the peri-urban interface and its inhabitants. High-rate AD will open new revenue streams from energy and by-products, which will support operational maintenance: this would be transformative indeed. Thus, and in summary, apart from the academic impacts, and the impacts on local practitioners and officials, the primary impact will be experienced by - and is aimed at - poor individuals and communities. In this light, we have placed at the centre of our project a product design process, which will focus on the relationship between the science and engineering, the system and the users.

Our programme is underpinned by a detailed process of on-site meetings with local practitioners and potential users. Engagement with stakeholders is - throughout the programme - key to the success of this project. The lab-based development phase will carefully consider the outcomes of that process. Importantly, maximum impact will be achieved by adopting a process of participatory innovation, whereby engagement and experiences between the team and the community, and between the community and the emerging technology, can drive the bioreactor development phase. We will ensure that the sociological and 'socio-technological' aspects can be incorporated into the scientific workpackages by melding our experiences and perspectives at the regular team meetings. There is an abundance of evidence to support the idea that technology needs to be embedded in the system and user. Technological success relies on 'embeddedness' in society, how it is accepted and used, and how both co-evolve. Our workplan is not based on a linear, science-driven approach; rather, it depends, at all stages on engagement with stakeholders and the development of a technology and a prototype product, which will result in a user-centred system.

Special workshops will be organized and used to engage and communicate with a range of local, national and global stakeholders, with targets in the South and, in the case of technology transfer at the end of this process, the North. A concluding conference will allow for wide dissemination to an academic audience. Internal communication will use video con-calls, and web portals to store notes, minutes and seminars. The team has significant industrial contacts (Severn Trent Water, Thames Water, Scottish Water), which will be exploited for potential implementation in the Global North.

Understanding local institutions and community dynamics will help the team to understand what will work or not, and how the technology will interact with local social, gender and power relations. Working with local partners, we will examine, in a total sanitation planning context, current sanitation solutions based on high-solids streams, and will compare with solutions, including AD, to identify critical success factors with respect to social acceptability; technical, environmental and economic sustainability; and potential for reproducibilty.