Assessing sanitary mixtures in East African cities

<p> 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/>