ARTICLE

News from the Swiss Novaquatis Project

By Rahel Gilg and Judit Lienert, Switzerland

Novaquatis

The research project Novaquatis of the Swiss Federal Institute for Environmental Science and Technology (EAWAG), which investigates the possibilities of urine source separation, is now well on the way. The project started in 2000 and will continue until 2005. Novaquatis consists of eight workpackages [= subprojects, the editor], including socioeconomic research, natural sciences, development of new technology, and cooperation with the emerging country China. Strong interactions with local water authorities and sanitary firms are maintained. For more information see the new Novaquatis Homepage (www.novaquatis.eawag.ch) or Lienert and Larsen (2002, subm.) for overviews of current research results.

Overview on some research results

Socioeconomic research

Three studies concerning socioeconomic aspects have been carried out. Apparently, Swiss citizens as well as Swiss farmers, two important stakeholders, show a positive attitude towards NoMix technology and urine-based fertilizers. Swiss citizen were questioned about their opinion on the NoMix technology in focus groups. About 90% of the women and about 70% of the men considered the NoMix toilet to be a good or very good idea. A majority would move into an apartment equipped with NoMix toilets and many are willing to purchase such a toilet. The requirements named were no additional costs and maintenance of today's level of comfort and esthetics (Pahl-Wostl et al., in press).

A mail survey with Swiss farmers showed that 57% of the responding farmers believed a urine-based fertilizer to be a good or a very good idea, and 42% were willing to buy it. Absolutely crucial for the acceptance is a hazard-free fertilizer, and concerns regarding micropollutants such as pharmaceutical residues and hormones in urine were high. The results are not quite representative since the response rate differed among groups of farmers (Lienert et al., in press).

Whilst the attitude of consumers and farmers is important, a recent analysis indicates that it is not the driving force for the successful introduction and fast diffusion of the NoMix technology (Larsen and Lienert, 2002). The main decision-makers are wastewater professionals (e.g. engineers, wastewater authorities) and their opinion is absolutely crucial. They will have to introduce the new concept and carry consequences of drawbacks. Hence, a strong commitment from the part of wastewater professionals is needed.

Development of new technology

One of the main problems with NoMix toilets is the clogging of urine-conducting pipes due to precipitation, which would hardly be accepted by users in Switzerland. Precipitations were intensively investigated by Udert et al. (subm.; in press b,c). A high fraction of phosphorus is incorporated into the precipitates. The main crystalline compounds are struvite, hydroxyapatite, and calcite. The composition depends on dilution with flushing water; computer simulations indicate that dilution diminishes the precipitation potential and thus the risk of blockages. The results show that there are no easy solutions to overcome the clogging problems in urine conducting pipes. Effective handling of precipitates from urine still demands large efforts and technological ingenuity.

Additionally, a first treatment method to stabilize urine and reclaim nutrients has been developed: aerobic biological treatment of urine, including partial nitrification (Udert et al., in press a).

In an ongoing dissertation, struvite precipitation in source separated and artificial urine is being studied. So far, the thermodynamics of struvite precipitation under controlled addition of three different forms of magnesium (magnesium chloride, magnesium oxide, magnesium hydroxide) has been evaluated in experiments and simulated with a computer model (Ronteltap et al., subm.)

Cooperation with emerging countries

A method for assessing existing and alternative measures in urban water management in emerging countries is being developed in an ongoing dissertation. The method (wastewater mass flux analyses) is based on a case study conducted in Zurich. Later it will be adapted to a case study in Kunming, China. The prototype of the method allows determining wastewater origins using statistical pattern recognition. The effect of urine source separation on wastewater properties was also assessed, taking in account the amount of wastewater, and the important substances ammonium (NH₄), total Kjeldahl nitrogen (TKN), and total phosphorous (TP; Huang et al., subm.)

References

Huang, D., R. Schertenleib, H. Siegrist, T.A. Larsen, W. Gujer: Developing a tool for assessing exist–ing and alternative measures of urban water management in fast growing emerging countries, Symposium 'ecosan - closing the loop', Lübeck 2003, submitted

Larsen, T.A., J. Lienert: Societal implications of re-engineering the toilet, Proceedings of the IWA Leading Edge Conference Series 'Sustainability in the Water Sector', Venice 2002, p. 29, submitted

Lienert, J., T.A. Larsen: Urinseparierung - eine Alternative für die schweizerische Siedlungswasserwirtschaft? gwa (Gas Wasser Abwasser), 11, 2002, pp. 819-826p>

Lienert, J., T.A. Larsen: Introducing urine separation in Switzerland: Novaquatis, an interdisciplinary research project, Symposium 'ecosan – closing the loop', Lübeck 2003, submitted

Lienert, J., M. Haller, F. Berner, M. Stauffacher, T.A. Larsen: How farmers in Switzerland perceive fertilizers from recycled anthropogenic nutrients (urine), IWA conference 'From Nutrient Re­moval to Nutrient Recovery', Amsterdam 2002, Water Science & Technology, in press

Pahl-Wostl, C., A. Schönborn, N. Willi, J. Muncke, T.A. Larsen: Investigating consumer attitudes towards the new technology of urine separation. IWA conference 'From Nutrient Re–moval to Nutrient Recovery', Amsterdam 2002, Water Science & Technology, in press

Ronteltap, M., M. Biebow, M. Maurer, T.A. Larsen: Precipitating struvite from source separated urine using different magnesium compounds, Symposium 'ecosan - closing the loop', Lübeck 2003, submitted

Udert, K.M., C. Fux, M. Münster, T.A. Larsen, H. Siegrist, W. Gujer: Nitrification and autotrophic denitrification of source-separated urine. IWA conference 'From Nutrient Re–moval to Nutrient Recovery', Amsterdam 2002a, Water Science & Technology, in press c

Udert, K.M., T.A. Larsen, M. Biebow, W. Gujer: Urea hydrolysis and precipitation dynamics in a urine-collecting system, Water Research, 2003a, in press a

Udert, K.M., T.A. Larsen, W. Gujer: Biologically induced precipitation in urine-collecting systems and urinal traps, IWA conference, Melbourne 2002b, Water Science & Technology, submitted

Udert, K.M., T.A. Larsen, W. Gujer: Estimating the precipitation potential in urine-collecting systems. Water Research, 2003b, in press b