This demonstration site has been one of the first pilot projects introduced in the Netherlands to treat vacuum collected black water (toilet wastewater). It was built in 2005 in Sneek, Lemmerweg-Oost, and is managed under the leadership of DeSaH. The black water of 32 houses is treated. Within Run4Life this demonstration site is upgraded: a new type of vacuum toilet, the ultra-low flush toilet, having extremely low water consumption, and a (Hyper-)Thermophilic Anaerobic Digestion (HTAD) technology are implemented. Both of these innovative technologies are established in large scale for the first time. Furthermore, the demosite aims to recover valuable products from the wastewater. Biogas will be produced during the HTAD and the effluent and solid fraction of the HTAD can directly be used as NPK fertilisers (thus recovering the nutrients from the black water).
Safe liquid and solid NPK fertiliser in a one-step treatment process
The new toilets implemented at this demosite are developed by JETS and halve the water consumption compared to conventional vacuum toilets, resulting in a highly concentrated black water stream. This is necessary to increase the efficiency of biogas production and nutrient recovery in the subsequent black water treatment.
The HTAD technology is an anaerobic digestion that occurs at high temperatures (55-70°C). It allows for the production of hygienically safe solid and liquid NPK fertilisers in a one-step process because most pathogens are inactivated at the applied temperatures. Furthermore, the high temperatures can enhance stabilisation of organic matter and could lead to reduced hydraulic retention times and thus smaller reactors. Because of the inactivation of pathogens and the shorter retention time, HTAD is an ideal production method for hygienic low impact fertiliser. The HTAD technology is currently being tested and optimised by the WUR and is implemented at DeSaH. The first results have been published and a summery can be found in the HTAD factsheet.
The anaerobic digestion takes place in an Upflow Anaerobic Sludge Blanket (UASB) reactor. During the anaerobic process COD is removed, nutrients are mineralized and biogas is formed. The biogas can be used as a bioenergy source to heat the anaerobic digestion and the connected houses. The HTAD reactor produces a solid and a liquid (effluent) fraction. Both will be used as NPK fertiliser products which are directly applicable in agriculture, due to the pathogen inactivation.
As many people, companies and organisations are involved in the Run4Life project, it is interesting to see how these groups are connected to one another and how they are involved in the project. This can help with identifying possible new stakeholders and collaborations. For this purpose, stakeholder maps for each demo site were created. The stakeholder map is a tool that shows the connections between stakeholders and can therefore help visualise the social context. The initial mapping of stakeholders and expectations for all demo sites is described in project report Deliverable 6.1 and more information on the social context of Run4Life can be found here.