2.1.02 Wastewater as a resource – the promising SANIRESCH demonstration project

Knowledge of new sanitary systems is growing in Germany. However, further research and development is required for all system components before production can begin. The “Sanitary recycling Eschborn” is helping to achieve this: the focus of its work is on how to implement the alternative solution approach and use wastewater in an environmentally compatible manner. A federally owned company is being used for the demonstration, and the initial results of the project are coming in.

The current level of knowledge within Germany about innovative sanitary systems is not yet sufficient to allow large-scale implementation: many of the technologies involved must be developed further (e.g. diversion-flush toilets), and approval is not yet in place for recovered products such as urine and struviteA sparingly soluble compound of ammonium and magnesium named after the scientist Heinrich Christoph Gottfried von Struve (1772–1851). to be used in farming. A research and demonstration project is looking into how this situation could be amended: “Sanitary recycling Eschborn” (SANIRESCH) is being run by the Deutschen Gesellschaft für Internationale Zusammenarbeit (GIZ, German association for international co-operation) with scientific support from RWTH Aachen University, the University of Bonn, Gießen university, Huber SE and Roediger Vacuum (period of study: 2009 to 2012).

The GIZ installed a sanitary system for the separate collection of urine, brown water and greywaterDomestic wastewater from the kitchen, bath, shower, washing machine etc. (no faecal matter or urine) (see also ->Brown and ->Urine water). when it modernised its main building in Eschborn near Frankfurt in 2006. This system includes diversion-flush toilets, waterless urinals, separate piping systems for urine, brown water and greywaterDomestic wastewater from the kitchen, bath, shower, washing machine etc. (no faecal matter or urine) (see also ->Brown and ->Urine water). and urine storage tanks. SANIRESCH is looking at how to treat and recycle wastewater, examining both staff acceptance of the new sanitary system and also how urine could be used in farming. Economic efficiency and ability to transfer the approach to other countries are additional considerations.

Numerous project modules

The project consists of various components, with the project partners working on these alone or in collaboration.

Sanitary and in-house installations: The GIZ headquarters features 25 waterless urinals (Keramag) and 48 diversion toilets (Roediger Vacuum) to separate the wastewater – the latter are being tested in continuous operation.

Plant technology: A precipitationIn this process, chemical reactions cause the transformation of dissolved substances into insoluble substances, which then settle at the bottom of a vessel or water body – e.g. in the form of flocs – where they can be more easily removed from the water. reactor is treating the collected urine using a chemical-physical process; magnesium oxide is added to produce solid magnesium ammonium phosphate (MAP), which is a valuable fertiliser for use in agriculture. Brown waterSanitary wastewater without urine (see ► Urine water). treatment takes place in a membrane bioreactorA bioreactor is a vessel in which microorganisms, cells or small plants can be cultivated or fermented under optimum conditions. The breakdown of chemical compounds using bacteria can also be performed in bioreactors. In this context, they play in important part in the biological cleaning of wastewater, for example. (MBR), once the solids have been removed. The MBR uses ultrafiltrationSee: Micro-filtration. to remove solids and bacteria, as well as almost all viruses. The resultant filtrate is then hygienic enough to use for irrigation. An MBR is also used to treat greywaterDomestic wastewater from the kitchen, bath, shower, washing machine etc. (no faecal matter or urine) (see also ->Brown and ->Urine water). (water from the kitchen sink/hand-washing), with the resultant process water being used to flush the toilets.

Operation and monitoring: The facilities in question are maintained and optimised on site. Remote technologyRemote system monitoring. is used to control and monitor the systems and to analyse the basic parameters of the wastewater.

Quality of the products / Storage of urine: When urine is stored, the pharmaceutical substances can degrade; this degradation is to be quantified. Lab tests are also being used to adapt the storage conditions (e.g. by varying the pH valueMeasure of the H+ ion concentration, i.e. of acidity (pH < 7) or basicity (pH > 7). A pH value of 7 is neutral.) so that urine storage can be improved in terms of removing harmful substances.

Agricultural production: SANIRESCH is conducting fertiliser tests using stored urine and MAP in the open field. The primary focus is the effects on renewable raw materials (miscanthus) and crops. The legal framework conditions for recycling urine in Germany are being clarified and recommendations are being developed for authorities.

Acceptance: Studies intend to determine the level of acceptance of urine as a fertiliser among users and cleaning staff at GIZ and also farmers and consumers.

Economic feasibility: One project module is dedicated to determining the costs of investment, operation and reinvestment, and also the amortisation point. The project also seeks to make an economic comparison of this concept with other technical solutions.

International adaptability: The objective is to determine regions particularly suited to the sanitary concept and the technologies used and to identify the ways in which they can be used. The necessary adaptation to be able to implement the technologies successfully in specific cases in emerging and developing countries is also being determined.

Initial project results

The research project was launched in July 2009; the following results relate to the first year of the project.

When it comes to employees, the urinals and toilets are the only visible components of the system. The state of the sanitary facilities is thus crucial to their acceptance. It became evident that the Roediger diversion toilets need to be modified: the valve responsible for diverting the urine has already been improved in order to facilitate installation and improve throughflow.

The urine storage tests showed that the urine contains pharmaceutical residues that even at the end of the six-month storage period were not completely eliminated. Initial measurements showed concentrations of heavy metals to be beneath the limits of the German Drinking Water Ordinance (TrinkwV, 2001); it is therefore assumed that this could be used within agriculture without any issues. Tests on the urine precipitated as MAP indicated that no active pharmaceutical agents were included within the precipitated product. Analysis is still required to determine whether agents are adhering to the surface of the MAP crystals and forming part of an organic matrix.

Regarding the effect of the fertiliser, an ongoing field test is fertilising parcels of land containing wheat and broad beans with urine. These crops have displayed good growth, equivalent from a visual perspective to those on parcels of land receiving mineral fertiliser. Although more detailed results are still pending, it is expected that there will only be slight differences in comparison with mineral fertiliser.

The economic feasibility study analysed the investment and operating costs of the sanitary installations implemented within the building (toilets, urinals, piping systems, urine tanks) compared with the conventional system, which was installed in the wings of the building at the same time. The sanitary installation costs for the SANIRESCH version were EUR 0.088 per use, compared with EUR 0.071 for the conventional version. This difference is due to the considerably higher investment costs.

Project website www.saniresch.de

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2.1.03 The “KOMPLETT” system

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2.1.01 Solutions for China’s major cities