PÓS-TRATAMENTO DE EFLUENTE DE REATOR ANAERÓBIO POR MICROFILTRAÇÃO E ULTRAFILTRAÇÃO

Abstract

The anaerobic reactors used in the treatment of wastewater need of post-treatment for better removal of organic matter, nutrients and microorganisms. This research aimed to evaluate the microfiltration and ultrafiltration technologies as post-treatment of anaerobic reactor effluents. RALF samples were collected at Riozinho Wastewater Treatment Plant (Irati – PR) and treated at microfiltration and ultrafiltration membrane pilot system. Were performed 3 campaign in triplicate serie of tests and the latter of them the samples were pretreated by coagulation/flocculation/sedimentation with PAC and Tanino in different dosages. In each test, the membrane system worked during 120 minutes. The obtained data were statistically analized by factorial ANOVA arrangement with interaction and 2 factors with 5% of significance level. The results show that the microfiltration and ultrafiltration technologies in optimal conditions reached as best removal efficiency for COD, phosphorus, turbidity, true color, ST, SST and STV percentages of 85.2%, 99.3%, 99.8%, 96.9%, 36.9%, 89.6% and 100%, respectively. The amounts measured for microbiological parameters established the efficiency of 99.89% and 99.87% for E. coli and CT, respectively. Both technologies (microfiltration and ultrafiltration) have proved as great alternatives in the after-treatment of secondary effluent where the best pollutant removal efficiencies in most parameters studied was at ultrafiltration. The pretreatment by coagulation helped to achieve better total phosphorus and turbity removal efficiencies in addition to providing higher permeate flow values during the microfiltration and ultrafitration treatments. The results obtained in hydraulic permeability said that the chemical cleaning was efficient with average rate of up to 97.9% recovery flow.