DEVELOPMENT OF THE WASTEWATER REHABILITATION SYSTEMS AND EVALUATION OF THE CHEMICAL/BIOLOGICAL CONTAMINANT ABATEMENT
The rehabilitation of washing machine wastewater is based on the complementary metabolic activities of the microbial partners of the consortium: the cyanobacteria provide oxygen to the catalytic activities of the heterotrophic bacteria through photosynthesis, while the heterotrophic partners consume the organic matter, mineralising the nutrients. The combined activity of the different microorganisms allows the recovery of nutrients (for example N and P) which the microorganisms use and accumulate in the biomass, rehabilitating the wastewater that can be used in the cultivation of edible or ornamental plants. Furthermore, the biomass of the microbial consortia can also be used as a biofertilizer, increasing the sustainability of the system.
In this framework, once defined the composition of the microbial consortium, its functionality and efficiency over time will be evaluated, by carrying out survival and growth tests of the consortium in the wastewater. Both the concentration of in vivo chlorophyll a (OD λ = 665 nm), proxy of the cyanobacterium growth, and the turbidity of the culture (OD λ = 730 nm), proxy of the growth of the entire microbial community will be evaluated. The increase in biomass will also be measured, together with the composition and structure of the consortium via DNA Metabarcoding (in Next Generation Sequencing). Furthermore, these analyses will be performed in parallel with other tests, evaluating the consortium's ability to reduce the concentration of nutrients present in the wastewater (total nitrogen and phosphorus) and of detergents (surfactants, enzymes, etc.) used in the washing process. For these tests, specific dedicated methods will be applied, using colorimetric methods, but also HPLC (High Performance Liquid Chromatography) and GC (gas chromatography) procedures.