Association of a UASB reactor and a submerged aerated biofilter for domestic sewage treatment

Abstract

This paper presents exploratory results on the association of an Upflow Anaerobic Sludge Blanket - UASB reactor (46 L) and a submerged aerated biofilter – BF (6.3 L) for domestic sewage treatment. The experimental period extended for 322 days, during which the hydraulic and organic loads were gradually increased in both reactors. Having the UASB as a reference, the following hydraulic loads were tested: 0.4 m3/m2.h (θ = 16 h); 0.6m3/m2.h (θ = 10h); 0.8 m3/m2.h (θ = 8 h); 1.0 m3/m2.h (θ = 6 h) and 1.45 m3/m2.h (θ = 4h). During the experiments carried out with the UASB reactor operating at a hydraulic detention time of 6 hours, related to a θ < 11′ in the granular media of the BF, the mean removal efficiency in terms of SS, BOD5 and COD, in both reactors, were respectively 94%, 96% and 91%. The final effluent, related to the BF effluent, presented the following mean characteristics: SS = 10 mg/L, BOD5 = 9 mg/L and COD = 38 mg/L. The results obtained in the last phase of the experiments, when the hydraulic load in the UASB reactor reached 1.45 m3/m2.h (θ = 4h), were similar to those obtained in the previous phase. These results demonstrate that submerged aerated biofilters can be considered a viable alternative for the post-treatment of effluents from UASB reactors treating domestic sewage. These reactors are capable of being operated with very short hydraulic detention times.

The Biological Aerated Filter (BAF) as alternative treatment for domestic sewage. Optimization of plant performance

“…These values are in accordance with those expected for the aerobic treatment systems through biofilm processes [20,21].…”

Attached growth systems for wastewater treatment in small and rural communities: a review

“…The introduction of an anaerobic step prior to RBC system would improve the removal efficiency of COD and significantly reduce the volume of the RBC system. 77 Table 4 summarizes the main characteristics of different anaerobic-aerobic units. Accordingly, it is recommended to use polyurethane rotating discs for post-treatment of anaerobically pre-treated sewage.…”

Post treatment of up-flow anaerobic sludge blanket based sewage treatment plant effluents: A review

“…Studies conducted by Goncalves and his coworkers have shown that UASB reactor + submerged aerated bio-fi lter systems are capable of maintaining stable operational conditions despite infl uent load variations and recycle of aerobic sludge discharged from the biofi lter (BF) [38][39][40]. Submerged aerated biofi lter can be installed to serve up to 3000 population equivalent (PE).…”