Huishoudwater : een nieuwe standaard?

Een vergelijking van drie huishoudwatersystemen (hemelwater-, oppervlaktewater- en grijswatersysteem) met het gangbare enkel-net-systeem op de punten economische rendabiliteit, milieurendement en maatschappelijke effecten. Behalve in het oosten van het land, waar de noodzaak van grondwaterbesparing het grootst is, zullen omvangrijke huishoudwaterprojecten er waarschijnlijk niet kome

Duurzame en robuuste sanitatie door decentralisatie

Kritiek op de huidige centralistische aanpak van sanitatie, transport, behandeling en hergebruik van huishoudelijk afval en afvalwater, en schets van een alternatief: DESAH (Decentrale Sanitatie en Hergebruik), waarbij wordt voldaan aan de criteria duurzaamheid, preventie en robuustheid. Scheiding van afvalstromen, eenvoudige zuiveringssystemen (anaeroob; biologisch), terugwinning van grondstoffen, en hergebruik in huishouden en landbouw spelen een belangrijke ro

SANitation CHoice Involving Stakeholders : a participatory multi-criteria method for drainage and sanitation system selection in developing cities applied in Ho Chi Minh City, Vietnam

Keywords: sanitation; drainage; planning; multi-criteria decision analysis; stakeholder dialogues, developing countries The poor living in slums and other unplanned urban areas in developing countries have no access to adequate drainage and sanitation provisions with grave consequences to their health and living conditions. This thesis takes an analysis of the causes and consequences of that provision deficit as point of departure and seeks more effective mechanisms for inclusive and environmentally sustainable drainage and sanitation implementation. This occurs at two levels. Firstly, there is the level of the developing cities in general, and secondly the level of Ho Chi Minh City, Vietnam. Despite political will for improvement and many ongoing urban upgrading projects, environmental agencies in Ho Chi Minh City appeared unable to meet the demand for adequate infrastructure. New fast-growing residential areas demonstrated a replication of the flooding and wastewater disposal problems, that are addressed in economically more important areas. The main cause seemed insufficient capacity in land and housing management. Small wastewater-treatment plants of hospitals, hotels, markets and residential projects, meant to reduce pollution in the absence of large-scale treatment works, showed serious shortcomings due to inadequate design and operation. As the mentioned provision deficit is analyzed as rooted in a top-down approach, with a too limited involvement of the users of systems, a more effective approach is sought in a bigger contribution of communities and private parties to project planning, implementation and operation, without denying the important role of government. The contribution of this thesis to a multi-stakeholder approach drainage and sanitation planning is SANCHIS (Sanitation Choice Involving Stakeholders). This planning methodology brings about a learning process in which experts and non-experts are enabled to connect local experience with systemic knowledge, in order to generate, assess and select sustainable drainage and sanitation solutions. The method is supported by a data-base which describes assessment criteria and 58 drainage and sanitation system options clustered into 12 groups. Subsequently, detailed descriptions of toilet, on-site treatment, transport, treatment, reuse and disposal technologies are presented. These enable the distinction between feasible and non-feasible system options in a situation under study and a comparison of performances of options. SANCHIS enables the application of material flow analysis of water, organic matter, nitrogen and phosphorus to identify the repartition of these substances over the gaseous, liquid and solid products of drainage and sanitation systems. SANCHIS also facilitates a quantitative analysis of methane emissions, energy consumption and capacity-cost relationships. In an application to three different types of residential areas in Ho Chi Minh City SANCHIS has proven its worth to systematically evaluate the strengths and weaknesses of drainage and sanitation system options. Through application during workshops in Ho Chi Minh City insight was gained in the possibilities of the method and in items to be improved. It was concluded, that the SANCHIS method led to a shared and deepened view of the addressed problem and its solutions and a strengthened commitment among stakeholders to realize the new infrastructure. The participation of stakeholders from a wide range of practices has likely delivered more specific options to choose from than if only provider-related experts had been offering options. The experiences confirmed the author’s expectation that multi-criteria decision methods are an essential element in a participatory approach in infrastructure development and that they can be tools in the transformation of infrastructure to environmental sustainability and increased involvement of a variety of public, community and private formal and informal actors. ==========================