Abstract

Microbial consortia are effective biofilters to treat wastewaters, allowing for resource recovery and water remediation. To re-use and save water in the domestic cycle, we assembled a suspended biofilm, a ‘biofilter’ to treat dishwasher wastewater. Bacterial monocultures of both photo- and hetero-trophs were assembled in an increasingly complex fashion to test their nutrient stripping capacity. This ‘biofilter’ is the core of an integrated system devoted to re-using and upcycling of reconditioned wastewater, partly in subsequent dishwasher cycles and partly into a vertical garden for plant food cultivation. The biofilter has been 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 has been 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 to the reuse and saving of water in household appliances.

Highlights

  • Microbial consortia can be efficiently used as biofilter for wastewater remediation

  • Integration of photo- and hetero-trophic bacteria allows for nutrient stripping in wastewater treatment

  • An ad hoc engineered consortium was built using Trichormus variabilis (Cyanobacteria) and 3 dishwasher wastewater isolates

  • The development of the consortium has been built in a step by step process of association in lab closed conditions

  • The consortium proved to be able to thrive in raw dishwasher wastewater and reduce its nutrient load self-assembling in suspended aggregates

Graphical Abstract

Graphical Abstract
Graphical Abstract
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Supplementary data