Chacon-Aparicio, S.; Villamil, J.A.; Martinez, F.; Melero, J.A.; Molina, R.; Puyol, D. Achieving Discharge Limits in Single-Stage Domestic Wastewater Treatment by Combining Urban Waste Sources and Phototrophic Mixed Cultures. Microorganisms2023, 11, 2324.
Chacon-Aparicio, S.; Villamil, J.A.; Martinez, F.; Melero, J.A.; Molina, R.; Puyol, D. Achieving Discharge Limits in Single-Stage Domestic Wastewater Treatment by Combining Urban Waste Sources and Phototrophic Mixed Cultures. Microorganisms 2023, 11, 2324.
Chacon-Aparicio, S.; Villamil, J.A.; Martinez, F.; Melero, J.A.; Molina, R.; Puyol, D. Achieving Discharge Limits in Single-Stage Domestic Wastewater Treatment by Combining Urban Waste Sources and Phototrophic Mixed Cultures. Microorganisms2023, 11, 2324.
Chacon-Aparicio, S.; Villamil, J.A.; Martinez, F.; Melero, J.A.; Molina, R.; Puyol, D. Achieving Discharge Limits in Single-Stage Domestic Wastewater Treatment by Combining Urban Waste Sources and Phototrophic Mixed Cultures. Microorganisms 2023, 11, 2324.
Abstract
This work shows the potential of a new way of co-treatment of domestic wastewater (DWW) and a liquid stream coming from the thermal hydrolysis of the organic fraction of municipal solid waste (OFMSW) mediated by a mixed culture of purple phototrophic bacteria (PPB) capable of assimilating carbon and nutrients from the medium. The biological system is an open single-step process operated under microaerophilic conditions at an oxidative reduction potential (ORP) < 0 mV with a photoperiod of 12/24 h and fed during the light Stage only, so the results can be extrapolated to outdoors open ponds operation by monitoring the ORP. The effluent mostly complies with the discharge values of the Spanish legislation in COD and P values (<125mg/L <2 mg/L), respectively, and punctually on values in N (<15mg/L). Applying an HRT of 3 d and a ratio of 100:7 (COD:N), the presence of PPB in the mixed culture surpassed 50% of 16S rRNA gene copies, removing 78% of COD, 53% of N and 66% of P. Furthermore, increasing the HRT to 5 d, removal efficiencies of 83% of COD, 65% of N and 91% of P were achieved. In addition, the reactors were further operated in a membrane bioreactor, thus separating the HRT from the SRT to increase the specific loading rate. Very satisfactory removal efficiencies were achieved by applying HRT and SRT of 2.3 and 3 d, respectively: 84% of COD, 49% of N and 93% of P despite low presence of PPB due to more oxidative conditions, which anyway step-by-step re-colonized the mixed culture until reaching >20% of 16S rRNA gene copies after 49 d of operation. These results open the door to scale up the process in open photobioreactors capable of treating urban wastewater and municipal solid waste in a single stage and under microaerophilic conditions by controlling the ORP of the system. This novel urban biorefinery allows reducing treatment costs of two urban wastes and embed them in the circular bioeconomy through water recycling and valorizing PPB biomass as a source of carbon, nitrogen and phosphorus.
Copyright:
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