Assessing sanitary mixtures in East African cities

The urbanisation of poverty and informality in East African cities poses a threat to environmental<br /> health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008).<br /> This makes conventional sanitation provision untenable citywide, giving rise to the emergence<br /> of sanitation mixtures. Sanitation mixtures have different scales, institutional arrangements, user<br /> groups, and rationalities for their establishment, location, and management. For assessing the<br /> performance of both the mixtures as a whole and the different sanitation approaches constituting<br /> these mixtures, novel approaches for analyses are required. This thesis, therefore, departs from<br /> the centralised-decentralised approaches to a modernised mixtures (MM) approach in seeking a<br /> more inclusive assessment of sanitary configurations taking into account public and environmental<br /> health, accessibility and flexibility of sanitation systems as sustainability criteria. To achieve this,<br /> the four objectives formulated for this thesis are to:<br /> 1. Make an inventory of sanitary systems in Kampala and Kisumu.<br /> 2. Assess and map sanitary systems along MM dimensions in Kampala and Kisumu.<br /> 3. Assess sustainability of sanitary systems on defined MM criteria in Kampala and Kisumu.<br /> 4. Enhance insights on the applicability of MM criteria as conceptual model, assessment and<br /> prescriptive tool for sanitary mixtures in East African cities.<br /> Case study cities were chosen from a typology of primary and secondary cities that have urban<br /> sewer systems since colonial times. The two cities were deemed to offer rich cases that would give<br /> a general outlook of other East Africa cities, thus can offer possibilities for generalization. The<br /> thesis utilised a multi-method and multi-level approach in data collection and analysis. A multicriteria<br /> analysis is used in sustainability performance assessment of sanitation systems based on<br /> defined MM criteria.<br /> Firstly, modernisation debates and resultant modernities in sanitation provision were reviewed<br /> in Chapter 2. The review shows that Western modernisation and resultant modernities and their<br /> structures of service provision have not resonated well in developing countries. Consequently,<br /> alternative theories that dispute a universal approach to modernity emerged to offer alternatives<br /> to modernisation. Alternative options are characterised by multiple rationalities, diversity and<br /> multiplicity. Modernities in terms of sanitation provision are further operationalized as competition<br /> between the proponents of centralised versus decentralised solutions. A third way of looking at<br /> sanitation modernisation that is more inclusive is advanced through the introduction of the MM<br /> approach.<br /> In Chapter 3, the presence of urban sewer systems in Kampala and Kisumu cities is assessed. The<br /> results show that urban systems are of medium scale and serve about 10% of the city population.<br /> They are publicly owned and managed by public enterprises under new public management.<br /> Besides, they are conventionally designed, constructed and operated without the involvement<br /> of end-users. Treatment plants are either overloaded, underutilised or treatment stages are<br /> mismatched. Consequently, about 30-70% of the treatment stages are not operational. Effluent<br /> discharge standards and bio-solids reuse requirements are not met, and the adopted treatment<br /> technologies are inappropriate for the investigated conditions. Sewer networks are supported by<br /> pumping stations and siphons that are only partially operational due to high operational costs and<br /> mechanical failures. Public sewerage is further plagued by urban informality and multiplicity of<br /> city spatial structures. Planned city core, and to a limited extent peri-urban areas, are served by<br /> public sewers, while sewer trunk lines pass through informal slum settlements without connections.<br /> In Chapter 4, satellite systems are analysed and configurations mapped. Satellite systems are<br /> intermediate semi-collective decentralised sewerage and treatment systems developed parallel to<br /> urban and onsite systems. They are provided by multiple actors, serve planned middle and high<br /> income residential, industrial complexes, endowed public and private universities, and government<br /> facilities. In terms of scale, they are community, neighbourhood and small-urban sanitation<br /> solutions. Besides, satellite systems are private sewerage systems that utilise gravity sewers and<br /> localised mechanised or non-mechanised treatment. The flows are based on land use or facility<br /> specific and are treated close to the point of generation. They are based on conventional designs<br /> and construction protocols without end-user involvement.<br /> Onsite systems in Kampala and Kisumu cities are examined in Chapter 5. Planning forecast<br /> indicates that onsite systems will dominate sewer (urban and satellite) systems beyond the next<br /> two decades. They are small-scale, highly decentralised and use simple technologies. Pit latrines<br /> dominate septic tanks in number, with eco-san on pilot scales and bio-latrine being a new<br /> sanitation option. Faecal sludge collection, treatment and safe disposal is dismal. The private<br /> sector dominates over local authorities in provision of faecal sludge services, but public sewerage<br /> agencies receive and co-treat faecal sludge with sewage although sewage works are not designed to<br /> receive faecal sludge. They are regulated by the Ministry of Health, enforced by the city councils<br /> and are provided by multiple actors solely or in partnership. Onsite sanitation can be a transient<br /> or permanent solution depending on mass flows and spatial requirements. However, for better<br /> sanitation provision, a permanent solution, with room for amendments to anticipate changes in<br /> space and mass flow is imperative.<br /> In Chapter 6, sustainability performance of sanitation systems are assessed following the defined<br /> three MM criteria. The performance shows that there is no sanitation system that is completely<br /> outcompeted in performance, neither are there systems with a very good performance. Sanitation<br /> system choices, consequently, are made among imperfect options, which call for balancing the<br /> various elements of sanitation provision to suit different policy and local contexts. Varying the<br /> assigned relative weight of the various criteria used in the overall MCA assessment indicates<br /> that generally, any slight increase in weight has an impact on systems that already have a high<br /> performance whereas in the case of systems with low performance the change is dismal or even<br /> negative. Therefore, programmes for improvement of sanitation systems might be directed to<br /> improvement options where systems already have a relatively high performance. However, those<br /> with a low performance may need comprehensive or even system reconfigurations for significant<br /> impacts to be realised.<br /> In conclusion, sanitation mixtures are theorised as the co-existence of different phases of<br /> modernity in tandem with local context variables. Thus, there is no one-fit-all paradigmatic way<br /> to sanitation provision if the local contexts are apparently different even within the same city.<br /> However, a shift of the centralised-decentralised dichotomy to modernised mixtures paradigm<br /> offers better impetus as it can utilise the advantages of both centralised and decentralised<br /> approaches without jeopardising existing provision pathways. The MM approach is helpful in assessing, mapping and describing sanitation systems in cities where sanitation mixtures are the<br /> norm rather than the exception.<br /> One way to modernise sanitation mixtures is by shifting the centralised-decentralised paradigm<br /> in order to modernise the mixed sanitation landscape. This is premised on the notion that such<br /> a shift will result in merging the strengths of centralised approach, e.g. economies of scale,<br /> efficiency, and convenience, with strengths of decentralised approach, e.g. accessibility, flexibility,<br /> participation, and reuse and recovery in development of intermediate systems configuration. This<br /> can be achieved through, among others, avoiding use of pumping stations, adoption of multiple<br /> service levels, involvement of private sector, servicing households at intermediate scale, and<br /> establishing sanitation suitability and management zones.<br /> The MM approach is also very helpful as a conceptual model for organising a research<br /> agenda which can be set along the four assessment dimensions of scale, management, flows<br /> and participation, as well as in searching for appropriate intervention measures along one or<br /> more of these dimensions. As an assessment and decision making tool, it is helpful in finding<br /> out which elements highlighted in the sustainability assessment need to be restructured and<br /> which need improvement in order to enhance their sustainability. However, translation of the<br /> proposed conceptual MM model into a mathematical model is a challenge yet to be explored.<br /> Considering its intrinsic dynamic character in dependence to varying spaces, flows, and scales<br /> along city development, a mathematical MM model would provide a regulatory design tool<br /> for city planners for adopting amendments to existing sanitation solutions. Obviously, up to<br /> date monitoring and inventory records are a pre-requisite for applying such a model, requiring<br /> institutional upgrading. Although the current results described in this thesis provide the basis<br /> for a more structured assessment and generalisation of sanitation mixtures, more research and<br /> contextualisation is needed in other regions, for further elaboration of MM model, and for the<br /> refinement of the assessment tool.<br /> &nbsp