Start-up strategies to develop aerobic granular sludge and photogranules in sequential batch reactors

Marcos Sales; Talita Marinho; Idayana C Marinho; Savia Gavazza; Mario T Kato; Bruna S Magnus; Lourdinha Florencio

doi:10.1016/j.scitotenv.2022.154402

Start-up strategies to develop aerobic granular sludge and photogranules in sequential batch reactors

Sci Total Environ. 2022 Jul 1:828:154402. doi: 10.1016/j.scitotenv.2022.154402. Epub 2022 Mar 8.

Authors

Marcos Sales¹, Talita Marinho², Idayana C Marinho³, Savia Gavazza⁴, Mario T Kato⁵, Bruna S Magnus⁶, Lourdinha Florencio⁷

Affiliations

¹ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: marcos.sales@ufpe.br.
² Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: talita.marinho@ufpe.br.
³ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil.
⁴ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: savia@ufpe.br.
⁵ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: mario.kato@ufpe.br.
⁶ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: bruna.magnus@ufpe.br.
⁷ Federal University of Pernambuco, Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation. Av. Academico Helio Ramos, s/n. Cidade Universitária, CEP 50740-530 Recife, PE, Brazil. Electronic address: flor@ufpe.br.

PMID: 35276148
DOI: 10.1016/j.scitotenv.2022.154402

Abstract

In this study, start-up strategies to develop conventional aerobic granular sludge (AGS) and algal aerobic granular sludge (AAGS) (photogranules), were investigated. The granulation experiment was conducted in four sequencing batch reactors (SBR), of which two were conventional SBRs (RC1, RC2) used as control, and two were photo-SBRs (R1, R2). R1 and RC1 were operated with a 40-min feeding during the reactors´ anaerobic cycle period, whereas R2 and RC2 with a 60-min feeding. All the reactors were operated in two phases with a C:N = 4:1 in Phase I and 8:1 in Phase II. In Phase I, AGS in RC1 and RC2 was formed 15 days before the AAGS development in R1 and R2. However, the AAGS generally presented better stability and higher diameter. On the other hand, AGS presented greater abundance of extracellular polymeric substances producing organisms, such as Xanthomonadacea and Rhodocyclaceae. Chemical oxygen demand (COD) and NH₄⁺-N removal efficiencies were similar in all the four reactors of approximately 70% and 60%, respectively. In this phase, despite the good biomass structure, the reactors were not able to completely oxidize the high influent concentration of NH₄⁺-N (100 mg.L^-1) and COD (400 mg.L^-1). This can be associated to the short time of the aerobic phase and low biomass content. In Phase II in all the reactors, a good increase in COD and NH₄⁺-N removal efficiencies to values above 95% and 93%, respectively, was achieved under a higher C:N ratio of 8 with lower influent concentration of NH₄⁺-N (50 mg.L^-1). The 60-min anaerobic feeding period in R2 and RC2 resulted in greater removal efficiency of nitrogen, confirming that small variation on cycle periods can affect the biomass composition; the biomass presented more compact granules and larger diameters under 60 min-feeding when compared with those obtained with 40 min-feeding in Phase I.

Keywords: C:N ratios; EPS-producing organisms; Granular stability; Nitrification and denitrification; Simultaneous carbon and nitrogen removal.

MeSH terms

Aerobiosis
Biological Oxygen Demand Analysis
Bioreactors
Nitrogen / analysis
Sewage* / chemistry
Waste Disposal, Fluid* / methods

Substances

Sewage
Nitrogen