Biorreator anaeróbio osmótico acoplado à destilação assistida por membranas como alternativa para potabilização de esgoto doméstico

Abstract

The performance of the integration of an anaerobic osmotic membrane bioreactor to membrane distillation (OMBR-MD) in the treatment of domestic sewage was assessed, aiming at the removal of micropollutants and the water potabilization. The study was divided into three stages. The first comprised the development of an submerged membrane module, that associated in the same unit the forward osmosis (FO) and the membrane distillation (MD) process. The steady-state operating conditions determined for this module were: feed temperature, SO and distillate corresponding to 20, 45 and 20 ° C, respectively. High removal efficiencies of organic matter (94.9%), total nitrogen (93.8%), ammonia nitrogen (99.8%), micropollutants (> 99.3%) and salinity (98%) were verified for hybrid module at the steady-state condition. In the second part of this study, the effect of salinity on the removal of the selected micropollutants were determined by anaerobic biodegradability assays. The salinity used in the tests were determined by simulation of an OMBR. The steady-state salinity determined were 20.7 g.L-1. Salinity inhibited the biogas production, while the presence of micropollutants increased it. The salinity had a different impact on the removal efficiencies of the micropollutants. For those mostly removed by abiotic mechanisms, salinity did not compromised the removal efficiencies. For betamethasone, removed by biotic mechanisms, a reduction in efficiency was observed, followed by subsequent recovery of the removal efficiencies. This indicated a possible acclimatization of the microbial species responsible for the degradation of this compound. For fluconazole and ketoprofen, salinity further reduced removal efficiencies, which were already lower even in the absence of salt. For 17α-ethinylestradiol, the salinity reduced its removal. This was associated with a possible inhibition of microorganisms that specifically act on its biodegradation. The final part of this study was the assessment of the integration of the hybrid module to an anaerobic bioreactor, configuring an OMBR-MD. High removal efficiencies of organic matter (97.1%), ammonia nitrogen (76.3%), phosphorus (> 94.9%) and micropollutants (97%) were verified. Additionally, 8 of the 9 parameters complied with the drinking water guidelines, among them Escherichia coli. This demonstrated the potential of the system in the sewage potabilization.