A quantitative microbial risk assessment was applied to evaluate the microbial risks of the Accra Urban Water System (AUWS). The exposure assessment was based on the count of
Water utilities particularly in the developing countries continue to operate with considerable inefficiencies in terms of water and revenue losses. With increasing water demand and scarcity, utilities require effective strategies for optimum use of available water resources. Diverse water loss reduction options exist. Deciding on which option to choose amidst conflicting multiple criteria and different interests of stakeholders is a challenging task. In this paper, an integrated multi-criteria decision-aiding framework for strategic planning of water loss management is presented. The PROMETHEE II method was applied within the framework in prioritizing water loss reduction options for Kampala city. A strategic plan that combines selective mains and service lines replacement and pressure management as priorities is the best compromise based on preferences of the decision makers and seven evaluation criteria characterized by financial-economic, environmental, public health, technical and social impacts. The results show that the most preferred options are those that enhance water supply reliability, public health and water conservation measures. This study demonstrates how decision theory coupled with operational research techniques could be applied in practice to solve complex water management and planning problems.
Apparent losses relate to water that is consumed but not paid for. Most research carried out in the last decade particularly in the United Kingdom focused mainly on leakage. Until now, there are no set procedures and guidelines for assessment of apparent losses. Much work remains to bring it to par with the available tools and methodologies for leakage management. In the absence of adequate data and proper methodology, most developed countries use default values, which tend to be lowest values for well-managed water systems, for computation of apparent losses. These may not be appropriate for developing countries. This paper presents a methodology for the assessment of different components of apparent losses based on field audit and operational data for Kampala city's water distribution system in Uganda. Metering inaccuracies and illegal use have been found to be significant components of apparent losses. Appropriate intervention strategies have been developed based on the assessment.
High levels of water losses in distribution systems are the main challenge that water utilities in developing countries currently face. The water meter is an essential tool for both the utility and the customers to measure and monitor consumption. When metering is inefficient and coupled with low tariffs, the financial sustainability of utilities is at stake. Apparent water losses caused by metering inefficiencies can be reduced by assessing meters' performance and identifying the main causes of inefficiency. This paper examines the performance of 3 meter models, on the basis of failure records for a developing world water utility in Kampala city, Uganda. The influence of sub-metering on meter accuracy is also examined. The results indicate a high meter failure rate (6.6%/year) in Kampala. Over 75% of failures were observed in the volumetric (oscillating-piston) meter types with the main cause of meter failure being particulates in water. The study also indicates an average reduction in revenue water registration of 18% due to sub-metering. The reduction was not because of water use efficiency but due to the combined effect of the metering errors of the sub-meters. This clearly implies that when properties are sub-metered, customers should be charged proportionately based on master meter readings, for accurate water accountability. The findings of this study will be useful for both utility managers and meter manufacturers who work in the water industry, especially in developing countries, to make appropriate metering and sub-metering decisions.
As the traditional supply-driven urban water management is not sustainable, water utilities should embrace water demand management (WDM) measures to meet increasing water demand. Developed countries are using different technological and management measures to reduce urban water demand as a part of their integrated urban water management strategy. However, all these measures might not be directly applicable for the developing countries. Furthermore, the developing countries might not have access to the technologies and skilled manpower as well as institutional set-up to apply these measures properly. In this context, this paper reviews the different tools, techniques and measures of urban water demand management (UWDM) applied in the developed countries and critically analyses the prerequisites, prospects and constraints likely to be faced in developing countries in adopting these techniques and measures. Furthermore, it outlines a set of activities that will best help the developing countries in attaining the full benefit of UWDM.Urban water demand management (UWDM) approaches UWDM measures offer multiple benefits. Reductions in water demand not only make available the additional
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