Efficiency of recycled PET biocarriers in moving bed biological reactors for municipal wastewater treatment

The present research valuates the efficiency of recycled polyethylene terephthalate (PET) biocarriers for the treatment of municipal wastewater in MBBR reactors. As part of the objective, the wastewater was characterized, and the process was stabilized in the experimental bioreactors until biofilm development. Subsequently, the experimental system was operated at different filling ratios (50 % and 30 %) and hydraulic retention times (HRT) of 6 and 8 hours. Finally, the quality of the effluent was analyzed by measuring temperature, pH, COD, BOD5, TSS and Turbidity. As a result, the formation of a loose and thin spongy biofilm was achieved in three weeks, with an average removal of 81.80 % for BOD5, 78.44 % for COD, 85.96 % for TSS and 94.13 % for turbidity. In addition, it was found that the filling factor had statistically significant effects and contributed more to the removal of BOD5 and TSS, while HRT was more influential in the removal of COD. It is concluded that PET biocarriers are efficient and, according to normative standards, the treated effluent is suitable to be discharged into a natural water body and/or to be reused for the irrigation of green areas restricted to the public or of indirect or occasional contact