Enhancing membrane bioreactors for dairy effluent treatment with a mixed mobile bed application.

This study examines the impact of incorporating a mobile bed into a membrane bioreactor (MBR) system on the treatment efficiency of dairy industry effluents. Initially, a conventional MBR system was operated for 60 days, followed by a modification that included a support material and ran for another 60 days under identical conditions. Performance was evaluated based on the removal efficiencies for soluble chemical oxygen demand (CODs), phenolic compounds, and oils and greases (OG), alongside measurements of solid content, dissolved oxygen, temperature, mixed liquor pH, and transmembrane pressure (TMP). The introduction of the mobile bed led to an increase in removal efficiencies for COD and phenolic compounds from 94.4 and 92.7% to 98 and 94.4%, respectively, marking statistically significant improvements (p < 0.05), while OG removal remained the same in both strategies (87.7%) (p > 0.05). Moreover, the modified system showed a more stable TMP profile, reducing the need for cleaning interventions compared to the conventional system, which experienced a notable TMP increase requiring cleaning at a 0.6 bar threshold. The findings suggest that integrating a mobile bed into MBR systems significantly enhances the treatment of dairy effluents, presenting an interesting solution for the upgrade of this type of system.

Degradação sazonal de efluentes têxteis por processo foto-Fenton solar mediado por ferrioxalato: descoloração e comportamento dos sólidos / Seasonal degradation of textile effluents through the solar photo-Fenton process mediated by ferrioxalate: discoloration and behavior of solids

RESUMO Neste trabalho foi avaliado o processo foto-Fenton solar mediado por ferrioxalato como tratamento primário de um efluente têxtil bruto (E1) e como um processo de polimento, após processo de lodos ativados (E2). Por um ano, ao menos uma vez por mês, a eficiência de descoloração e o comportamento dos sólidos foram avaliados sob condições naturais de radiação, temperatura e características dos efluentes. As condições operacionais foram as seguintes: 50 mg L-1 de ferro, pH 5, 525 mg L-1 de H2O2, administrados em dosagens decrescentes. O oxalato foi adicionado na razão molar de 1:3 [Fe+3:(C2O4)-2]. A descoloração máxima de E1 foi de 67% para intensidade de radiação de 690 W m-2; já a de E2 foi de 95% para intensidade de 620 W m-2. Houve considerável aumento na turbidez e nos sólidos suspensos em função da precipitação do ferro e de sua ação coagulante. A degradação do complexante durante o processo no E2 em dias ensolarados provocou elevada sedimentabilidade dos sólidos do efluente final, resultando em um sobrenadante clarificado, o que não ocorreu em dias nublados.

ABSTRACT This work evaluates the solar photo-Fenton process mediated by ferrioxalate as a primary treatment of raw textile effluent (E1) and as a polishing step, after active sludge process (E2). For a year, at least once a month, the color removal's efficiency and solids' behavior in the oxidative process treatment were analyze under natural conditions of light, temperature and effluents characteristics. The operational parameters values were: 50 mg L-1 iron, pH 5, 525 mg L-1 H2O2, introduced in decreasing doses. The oxalate was added at the molar ratio of 1:3 [Fe+3:(C2O4)-2]. The color removal of E1 was 60% for 690 W m-2 of radiation intensity and 95% for 620 W m-2 intensity to E2. Considerable increases were observed in turbidity and suspended solids due to the iron precipitation and the consequent coagulant action. In sunny days, the complex degradation in E2 resulted in high settle ability of solids in the final effluent, resulting in a clear supernatant. This has not happened in cloudy days.