THE JETSONS’ KITCHEN: SYSTEMS FOR THE UP-CYCLING OF DOMESTIC WASTEWATERS. THE ZERO MILE PROTOTYPE FOR THE DISHWASHER WASTERWATER

The Jetsons' Kitchen project addresses a specific environmental problem: the consumption of water resources in the household appliances. The problem was tackled in an interdisciplinary way and the first household appliance taken into consideration has been the dishwasher. For the recycling of the dishwasher wastewater, a system was designed capable of using the dishwasher wastewater partly for the production of vegetables in a vertical vegetable garden integrated into the kitchen area (at zero km, hence the name Zero Mile) and partly in the next rinsing cycle. The heart of the system is an ad hoc engineered biofilter, based on the mutualistic relationship between autotrophic and heterotrophic microbial partners, which makes the biodegradation process efficient and sustainable over time. The project was the subject of a national patent (N° 102019000004583, filed on 03/27/2019), expanded internationally in 2020 (WIPO/PCT WO 2020/194224 A1).

 The problem of water consumption is addressed (i) by selecting innovative washing technologies in order to reduce the consumption and use of low-impact detergents; (ii) integrating the treatment of the nutrients present in the wastewater with the cultivation of ornamental/edible plants that conclude the process of filtration of wastewater and improve the quality of indoor air; (iii) developing a new type of household appliance, an interactive appliance able to clean flatware and to produce zero-mile vegetables, affecting food habits and environmental awareness of the users.

 The research is based on experimental and user-centered methodologies applied for the evaluation of technologies and the development of the demonstration prototype and has the general objective of promoting new types of products able to reduce the environmental impact of domestic activities and support the modification in ecological sense of user behavior.

The development of this interdisciplinary project would have never been possible without the contribution of the researchers of the Design Department from the Polytechnic of Milan, particularly Fiammetta Costa, Attilio Nebuloni and Giorgio Buiatti.

 

 Alabiso A., Frasca S., Cantelmo V., D’Andrea M.M., Braglia R., Scuderi R., Costa F., Savio S., Congestri R. and Migliore L. (2023). A DIRTY JOB: DISHWASHER WASTEWATER REUSE AND UPCYCLE THROUGH AN AD HOC ENGINEERED MICROBIAL CONSORTIUM. npj Clean Water, 6:66. DOI: https://doi.org/10.1038/s41545-023-00280-8

 

In the framework of regenerative circular economy and Sustainable Development Goals #6, water demand and wastewater production are a crucial environmental issue. To cope with this, a system called Zero Mile has been conceived to reuse/upcycle the dishwasher wastewater in both fertilisation of a vertical garden (for home plant production at zero mile) and the subsequent dishwasher rinsing cycle. The core of the Zero Mile system is a biofilter constituted by an ad hoc engineered microbial consortium, based on the mutualistic relationship between autotrophic and heterotrophic microbial partners, that makes the biodegradative process sustainable over time. Two semi-batch tests were performed to evaluate the capability and the efficiency of the microbial consortium to operate in conditions mimicking the Zero Mile system: consortia were challenged in two dishwasher wastewater volumes (50 and 500 mL), with a replenishing rate of 4 days for ¼ of the dishwasher wastewater volume. The results of these tests showed that the consortium thrives well in dishwasher wastewater over time and can survive with the volume and rates of replenishments. Next Generation Sequencing showed that the microbial consortium maintains a stable taxonomic composition, and chemical analyses demonstrated a very high bioremediation efficiency (total nitrogen and phosphorus removal). Aiming to contribute to the circular economy approach, the consortium ‘treated’ dishwasher wastewater was useful for plant fertilisation, as demonstrated by pigment content and quality indices (total phenols and flavonoids, soluble solids) measured in the lettuce plants grown in the Zero Mile demonstrator and watered with consortium reclaimed dishwasher wastewater.

 

AA.VV. (2021) - THE JETSONS’ KITCHEN. A ZERO-MILE SYSTEM FOR WASTE WATER RECYCLING AND CULTIVATION. (F. Costa & A. Nebuloni, Eds.). Franco Angeli s.r.l., Milano. ISBN e-book Open Access: 9788835115748 ONLINE

The book aims to investigate the up-cycling of domestic effluents for plant production, bringing together a series of considerations by an interdisciplinary group of researchers from the Politecnico di Milano, Università Statale di Milano and Università di Roma Tor Vergata, ranging from biology to design through sociology and architectural composition. Integrating vegetable cultivation in the domestic environment with reusing kitchen wastewater for irrigation is a promising strategy for reducing freshwater consumption, limiting the amount of wastewater to be treated producing healthy plant food and, ultimately, raising environmental awareness among citizens. A first step in this direction is the experimental project to reuse dishwasher effluents in living spaces (kitchen, household, and community level), as described in the book. Dishwasher effluents were chosen as an initial bench test because of their high nutrient content, low harmful elements and constant wastewater quantity and quality, where treatment may consist of a combination of several chemical, physical and biological processes. Studies for the development of a domestic biofilter containing a consortium of microalgae and heterotrophic bacteria are also presented.

 

Congestri R., Savio S., Farrotti S., Amati A., Krasojevic K., Perini N., Costa F., Migliore L. (2020) - DEVELOPPING A MICROBIAL CONSORTIUM FOR REMOVING NUTRIENTS IN DISHWASHER WASTEWATER: TOWARDS A BIOFILTER FOR ITS UP-CYCLING. Water Science & Technology, 82 (6): 1142–1154. DOI: 10.2166/wst.2020.325

Microbial consortia are effective biofilters to treat wastewaters, allowing for resource recovery and water remediation. To reuse and save water in the domestic cycle, we assembled a suspended biofilm, a ‘biofilter’ to treat dishwasher wastewater. Bacterial monocultures of both photo- and heterotrophs were assembled in an increasingly complex fashion to test their nutrient stripping capacity. This ‘biofilter’ is the core of an integrated system (Zero Mile System) devoted to reusing and upcycling of reconditioned wastewater, partly in subsequent dishwasher cycles and partly into a vertical garden for plant food cultivation. The biofilter was assembled based on a strain of the photosynthetic, filamentous cyanobacterium Trichormus variabilis, selected to produce an oxygen evolving scaffold, and three heterotrophic aerobic bacterial isolates coming from the dishwasher wastewater itself: Acinetobacter, Exiguobacterium and Pseudomonas spp. The consortium was constructed starting with 16 isolates tested one-to-one with T. variabilis and then selecting the heterotrophic microbes up to a final one-to-three consortium, which included two dominant and a rare component of the wastewater community. This consortium thrives in the wastewater much better than T. variabilis alone, efficiently stripping N and P in short time, a pivotal step for the reuse and saving of water in household appliances.

 

 Costa F., Amati A., Antonelli M., Cocetta G., Di Mauro M., Ferrante A., Krasojevic K., Mangiarotti R., Meraviglia M., Nebuloni A., Perego P., Sironi R., Spanu F., Standoli C.E., Vignati G., Volonté P., Ziyaee M. and Migliore L. (2018) - DESIGNING THE FUTURE: AN INTELLIGENT SYSTEM FOR ZERO-MILE FOOD PRODUCTION BY UPCYCLING WASTEWATER. Proceedings, 2(22): 1367 DOI: 10.3390/proceedings2221367

 The project deals with the environmental problem of water consumption. The aim of this work is to experiment the recycling of dishwasher wastewater through its reuse in growing edible vegetables or ornamental plants; this can also accomplish the valorization of nutrients present in the wastewater. This new process allows to ensure washing functions coupled with vegetables production and to affect users’ environmental awareness and habits, following a user-centered system design approach to understand the users and involve them actively in the system development. The presented work is also aimed to experiment a multidisciplinary approach in order to face environmental problems.