Banca de DEFESA: HENRIQUE CESAR GUEDES CAMPOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : HENRIQUE CESAR GUEDES CAMPOS
DATE: 18/02/2022
TIME: 08:00
LOCAL: Auditório Pós-Graduação em Engenharia Civil on line
TITLE:

Influence of Different Mixing Modes on the Development of Granular Biomass and Algal-Bacterial Consortium in Sequential Batch Reactors Using Synthetic Sewage of Low Organic Load.

KEY WORDS:

Aerobic granular sludge; Algal-bacterial granular consortium; Mixing modes; Recirculation; Air pulses.

PAGES: 84
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The aerobic granular sludge (AGS) system is a promising technology to carry out the treatment of domestic sewage, due to its ability to simultaneously remove organic matter and nutrients in reactors that do not require the use of support material. This feature, compared to activated sludge, is of great interest for the circular economy, given that its use becomes viable in compact ETE's and requires low operating costs. However, one of the main difficulties of AGS cultivation is stability for long periods of operation. For this, some studies have been developed to overcome this problem. Among them are the algae-bacteria consortium, where through the production of EPS, stimulated by the competition for substrate between bacteria and algae, and the development of filamentous microorganisms, they promote the union and increase the stability of the system. In addition, research indicates that the insertion of system management strategies, such as the inclusion of anaerobic phase, increases the stability of granular biomass and nutrient removal in the system. In the present study, the influence of two different mixing modes was evaluated aiming at the development of aerobic granules and photogranules in sequence batch reactors (SBR), using synthetic sewage of low organic load. Four SBR operated simultaneously, two of them with aerobic granular sludge (SBR1 and SBR2) and two with granular algal-bacterial consortium (AGS-AB, SBPR1 and SBPR2). The reactors were operated with 4h cycles and two different biomass and influent mixing strategies, in the anoxic phase during the first 60 min of the cycle were used: SBR1 and SBPR1 were operated with a mixing regime through pulses of air and; SBR2 and SBPR2 worked with influent recirculation to promote greater contact with the biomass. Despite having an irregular surface, granular aggregates were reported at 22 days of operation for SBR1 and SBR2, while for SBPR1 and SBPR2, 22 and 37 days were required, respectively, indicating that the mixing mode with air pulses developed more quickly granules and photogranules. However, from the observations made under the microscope, the reactors with recirculation proved to be more tolerant to the action of Aeolosoma hemprichi, keeping the biomass stable for longer in the system. The rapid formation of granules in the system may also be related to the presence of Lactococcus, which are bacteria related to the production of EPS. The average COD removal efficiencies were 84% for both SBR's and SBPR2, while SBPR1 showed 79% efficiency. Low phosphorus removal values were obtained, with averages lower than 30% for the four reactors. This result may be a consequence of the short period of aerobic granules and photogranules in the system, causing a disadvantage of phosphorus accumulating organisms (PAO) in the system. As these are slow-growing bacteria, the presence of PAO was only observed through molecular biology when the concentration of VSSLM was low and the system was already collapsing. With the emergence of granular aggregates, NTK removals reached values of 85%, 83%, 87% and 71% for SBR1, SBR2, SBPR1 and SBPR2, respectively. These values can be justified by the presence of bacteria of the Pseudomonas genus (RA: 4%), with the ability to perform denitrification. In terms of treatment efficiency, it had little influence on the mixing modes, with a significant difference being perceived in the initial development (pulses of air) and in the maintenance of the aggregates throughout the research (recirculation).

BANKING MEMBERS:
Presidente - 3133998 - BRUNA SCANDOLARA MAGNUS
Externo ao Programa - 3141471 - FABRICIO MOTTERAN
Externo à Instituição - JOSE ROBERTO SANTO DE CARVALHO - UFPE
Externa à Instituição - SHYRLANE TORRES SOARES VERAS - UFPE