## 5 Conclusions  
The results obtained in this preliminary research, in particular N removal (about 50% in the indoor setup and about 70% in the outdoor setup) and the decrease in _E. coli_ content in the medium (>99% in both setups), suggest that this alga can efficiently depart and disinfect WWs in the winter season when suboptimal environmental conditions happen. Even if the results regarding P removal were unsatisfying, it is important to note that the increase in P concentration in the medium of both experiments was not directly ascribable to microalgae metabolism. Therefore, more research is needed to understand the interactions between the microalgae and the native microbial consortium. Moreover, fine-tuning of environmental parameters is needed, with particular regard to photoperiod, which proved to be crucial for biomass production. Nonetheless, even if no biomass production was recorded in the outdoor setup, the presence of lipids inside the cells paves the way for biomass reuse after effluent deprivation, such as biofuel production.  
Considering the results obtained, in particular, in the outdoor culture, semi-continuous cultivation may be considered for future tests, with the discharge of effluent after proper deprivation has happened and the addition of fresh WW. Furthermore, more tests are needed to evaluate the potential use of this microalga for WW remediation and disinfection throughout the year and for a further scale-up of the system.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15084235/s1](https://www.mdpi.com/article/10.3390/app15084235/s1)]([https://www.mdpi.com/article/10.3390/app15084235/s1](https://www.mdpi.com/article/10.3390/app15084235/s1)), Table S1: Results of the parametric one-way analyses of variance (ANOVA) analyses for the indoor experiments.; Table S2: Results of the parametric one-way analyses of variance (ANOVA) analyses for the outdoor experiments.  
Conceptualization, S.P., C.B., P.G. and G.Z.; methodology, P.G., S.D., E.B., L.F., S.P. and C.B.; validation, S.P., C.B. and S.D.; formal analysis, P.G., E.B. and L.F.; investigation, P.G., E.B., S.D. and G.Z.; writing--original draft preparation, P.G.; writing--review and editing, S.P., C.B. and P.G.; visualization, P.G.; supervision, S.P. and C.B.; project administration, S.P.; funding acquisition, S.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by PR-FESR EMILIA ROMAGNA 2021-2027 Priorita 1 Obiettivo specifico 1.1 Azione 1.1.2 CUP F37G22000200003 ID 37894 PG/2023/310511.  
Not applicable.  
The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.  
The authors thank the National Recovery and Resilience Plan (NRRP), Mission 04 Component 2 Investment 1.5--NextGenerationEU, Call for tender n. 3277 dated 30 December 2021 Award Number: 0001052 dated 23 June 2022.  
Author [PERSON] was employed by the company Hera S.p.A. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.