Effect of the co-treatment of synthetic faecal sludge and wastewater in an aerobic granular sludge system

Mary Luz Barrios-Hernández, Claribel Buenaño-Vargas, Hector García, Damir Brdjanovic, Mark C.M. van Loosdrecht, Christine M. Hooijmans

Research output: Contribution to journalArticleScientificpeer-review

1 Downloads (Pure)

Abstract

The co-treatment of two synthetic faecal sludges (FS-1 and FS-2) with municipal synthetic wastewater (WW) was evaluated in an aerobic granular sludge (AGS) reactor. After characterisation, FS-1 showed the following concentrations, representative for medium-strength FS: 12,180 mg TSS L−1, 24,300 mg total COD L−1, 93.8 mg PO3-P L−1, and 325 mg NH4-N L−1. The NO3-N concentration was relatively high (300 mg L−1). For FS-2, the main difference with FS-1 was a lower nitrate concentration (18 mg L−1). The recipes were added consecutively, together with the WW, to an AGS reactor. In the case of FS-1, the system was fed with 7.2 kg total COD m−3d−1 and 0.5 kg Nitrogen m−3d−1. Undesired denitrification occurred during feeding and settling resulting in floating sludge and wash-out. In the case of FS-2, the system was fed with 8.0 kg total COD m−3d−1 and 0.3 kg Nitrogen m−3d−1. The lower NO3-N concentration in FS-2 resulted in less floating sludge, a more stabilised granular bed and better effluent concentrations. To enhance the hydrolysis of the slowly biodegradable particulates from the synthetic FS, an anaerobic stand-by period was added and the aeration period was increased. Overall, when compared to a control AGS reactor, a lower COD consumption (from 87 to 35 mg g−1 VSS h−1), P-uptake rates (from 6.0 to 2.0 mg P g VSS−1 h−1) and NH4-N removal (from 2.5 to 1.4 mg NH4-N g VSS−1 h−1) were registered after introducing the synthetic FS. Approximately 40% of the granular bed became flocculent at the end of the study, and a reduction of the granular size accompanied by higher solids accumulation in the reactor was observed. A considerable protozoa Vorticella spp. bloom attached to the granules and the accumulated particles occurred; potentially contributing to the removal of the suspended solids which were part of the FS recipe.

Original languageEnglish
Article number140480
Number of pages12
JournalScience of the Total Environment
Volume741
DOIs
Publication statusPublished - 2020

Keywords

  • Aerobic granular sludge
  • Co-treatment
  • Digested faecal sludge
  • Protozoa
  • Suspended solids
  • Vorticella spp.

Fingerprint Dive into the research topics of 'Effect of the co-treatment of synthetic faecal sludge and wastewater in an aerobic granular sludge system'. Together they form a unique fingerprint.

  • Cite this