Microbial population dynamics in response to increasing loadings of pre-hydrolyzed pig manure in an expanded granular sludge bed

Haoyu Wang; Yu Tao; Dawen Gao; Gang Liu; Chunhong Chen; Nanqi Ren; Jules B van Lier; Merle de Kreuk

doi:10.1016/j.watres.2015.09.008

Microbial population dynamics in response to increasing loadings of pre-hydrolyzed pig manure in an expanded granular sludge bed

Water Res. 2015 Dec 15:87:29-37. doi: 10.1016/j.watres.2015.09.008. Epub 2015 Sep 7.

Authors

Haoyu Wang¹, Yu Tao², Dawen Gao³, Gang Liu⁴, Chunhong Chen³, Nanqi Ren⁵, Jules B van Lier⁴, Merle de Kreuk⁴

Affiliations

¹ State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 150090, Harbin, China; Section of Sanitary Engineering, Department of Water Management, Delft University of Technology, 2628, CN Delft, The Netherlands.
² State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 150090, Harbin, China; Section of Sanitary Engineering, Department of Water Management, Delft University of Technology, 2628, CN Delft, The Netherlands; Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, UK.
³ State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 150090, Harbin, China.
⁴ Section of Sanitary Engineering, Department of Water Management, Delft University of Technology, 2628, CN Delft, The Netherlands.
⁵ State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 150090, Harbin, China. Electronic address: rnq@hit.edu.cn.

PMID: 26378729
DOI: 10.1016/j.watres.2015.09.008

Abstract

In recent years, pig manure (PM) has been regarded as a valuable substrate for energy and resource recovery via bioprocesses such as anaerobic digestion (AD), however, the efficiency of digesting raw PM is limited by the presence of refractory compounds. In this study, we applied a series of pretreatment on raw PM, consisting of subsequent thermochemical pretreatment, enzymatic hydrolysis, tyndallization and filtration. The liquid PM hydrolysates were fed to an expanded granular sludge bed (EGSB) for the production of biogas. The general performance and population dynamics of the EGSB reactor were assessed during an extended operational period of 339 days. An efficient and stable digestion process was achieved under high organic loading rates (OLRs) up to 21 kg-COD/(m(3)·d), agreeing with a sludge loading rate of 0.75 kg-COD/(kg-VSS·d), 1600 mg-NH4(+)-N/L and 17 mg/L of free ammonia nitrogen. The tyndallization decreased the total amount of active cells from 1 × 10(8) to 1 × 10(2) CFU/ml. Hence, bio-augmentation with pigs' intestinal microbiota was absent and the community dynamics were mainly credited to the composition of the substrate (i.e. PM hydrolysates) and the environmental conditions inside the reactor. The results showed the influence of both the seed community and the imposed loading rates on the evolutionary trajectory of the EGSB microbial community. Four bacterial genera (Clostridium, Cytophaga, Bacillus and Bacteroides) and two methanogenic genera (Methanosaeta and Methanobacterium) dominated the communities. An obvious shift from aceticlastic Methanosaeta to hydrogenotrophic Methanobacterium appeared when the OLR was increased to over 10 kg-COD/(m(3)·d).

Keywords: Ammonia; Anaerobic digestion; Microbial community; OTU network; Organic loading rate; Pig manure.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anaerobiosis
Animals
Bacteria / genetics
Biofuels
Bioreactors / microbiology*
Filtration
Hot Temperature
Hydrolysis
Manure / microbiology*
Sewage / chemistry*
Sewage / microbiology*
Sus scrofa
Waste Disposal, Fluid / methods

Substances

Biofuels
Manure
Sewage