Using a UASB reactor for thickening and digestion of discharged sludge from submerged aerated biofilters

Abstract

Results from one year of experimental monitoring the wastewater treatment plant of UFES (Federal University of Espírito Santo) treating a residential urban area of city of Vitoria ES, Brazil, have shown a good performance by a UASB reactor as a part of domestic sewage treatment and also performing aerobic sludge thickening and digestion. The total solids concentration around 6% was obtained in main sludge blanket at bottom of reactor despite a high daily aerobic sludge load discharged from four aerobic submerged biofilters containing 0.4% TS and 80% of VS/TS. Similar values were found in another experimental period when the reactor was fed only with raw domestic sewage. The average removal efficiency of organic matter and suspended solids observed for domestic sewage treatment are around 63% of SS and 64% COD. These results were obtained in the UASB reactor working with or without aerobic sludge recycling, with constant or variable load and hydraulic detention time (HDT) less than 6 hours. A proposed mass balance allows a theoretical assessment of aerobic sludge digestion and accumulation into UASB reactor.

Behaviour of a full-scale expanded bed reactor with overlaid anaerobic and aerobic zones for domestic wastewater treatment

“…mS eu and mS xu (Figure 3a). These results also indicate that the EBANAR under these operational conditions showed the capacity to treat organic and hydraulic loads, respectively, three and ten times more than the upflow anaerobic sludge blanket (UASB) reactor used in the treatment of municipal wastewater (Cavalcanti et al, 2002;Gonçalves et al, 2002).…”

The Application of an Upflow Anaerobic Sludge Blanket Reactor in the Treatment of Brewery and Dairy Wastewater: A Critical Review

“…Biofilm forms on the packing media, through which UASB effluent passes towards the reactor's bottom [18]. The Figure 9 presents an exemplary simplified diagram of the UASB-BF hybrid system [115].…”

“…Biofilm forms on the packing media, through which UASB effluent passes towards the reactor's bottom [18]. The Figure 9 presents an exemplary simplified diagram of the UASB-BF hybrid system [115]. The biofilter media can consist of materials such as polystyrene, sand, anthracite, zeolites, expanded clay, and a variety of organic waste materials, such as peanut shells, coconut fibres, woodchips, rice straw, and date palm fibres [116].…”

Pathogen removal efficiency from UASB + BF effluent using conventional and UV post-treatment systems

“…The study was carried out at the Wastewater Treatment Plant (WWTP) situated at the Federal University of Espirito Santo (UFES, Brazil) receiving domestic sewage with average characteristics from a residential urban area of Vitória (south-east Brazil). The WWTP (capacity 2 L/s domestic sewage) comprised a single UASB reactor (35 m 3 ), three secondary submerged aerated biofilters (12 m 3 ) and one tertiary filter associated in series (Gonçalves et al, 2002). This configuration was able to produce <5NTU effluent, allowing easier UV disinfection (Figure 1).…”