Treatment of the liquid phase of digestate from a biogas plant for water reuse

Piotr Świątczak; Agnieszka Cydzik-Kwiatkowska; Magdalena Zielińska

doi:10.1016/j.biortech.2018.12.077

Treatment of the liquid phase of digestate from a biogas plant for water reuse

Bioresour Technol. 2019 Mar:276:226-235. doi: 10.1016/j.biortech.2018.12.077. Epub 2018 Dec 24.

Authors

Piotr Świątczak¹, Agnieszka Cydzik-Kwiatkowska², Magdalena Zielińska²

Affiliations

¹ University of Warmia and Mazury in Olsztyn, Department of Environmental Biotechnology, 10-709 Olsztyn, Słoneczna 45 G, Poland. Electronic address: piotr.swiatczak@uwm.edu.pl.
² University of Warmia and Mazury in Olsztyn, Department of Environmental Biotechnology, 10-709 Olsztyn, Słoneczna 45 G, Poland.

PMID: 30640016
DOI: 10.1016/j.biortech.2018.12.077

Abstract

Biogas plants struggle with managing nitrogen-rich digestate from manure co-digestion. In this study, the biologically treated liquid phase of digestate from an aerobic granular sludge batch reactor (GSBR) containing oxidized nitrogen forms (NO_x), phosphorus, COD and total suspended solids was post-denitrified (P-D), and then ultrafiltered. In P-D, various hydraulic retention times (from 10 to 60 h) and biomass concentrations (from 6 to 14 g MLSS/L) were tested. Then, waste glycerin (GL) was added to the P-D reactor at a COD_GL/NO_x ratio of 1.1, causing a large number of phosphate-accumulating and denitrifying Janibacter sp., and PHB-accumulating and denitrifying Paracoccus sp. and Thauera sp. to be present in granules, which improved nutrient removal. The effluent was ultrafiltered at 0.3 and 0.5 MPa. After biological treatment supported with GL and followed by ultrafiltration, the purified liquid phase of the digestate met FAO standards for water reuse for irrigation.

Keywords: Denitrifiers; Digestate; Post-denitrification; Ultrafiltration; Waste glycerin.

MeSH terms

Biofuels*
Biomass
Bioreactors
Denitrification
Sewage
Water

Substances

Biofuels
Sewage
Water