Energies 2014, 7(2), 785-803; doi:10.3390/en7020785
Article

The Influence of Loading Rate and Variable Temperatures on Microbial Communities in Anaerobic Digesters

Received: 26 November 2013; in revised form: 22 January 2014 / Accepted: 28 January 2014 / Published: 18 February 2014
(This article belongs to the Special Issue Biomass and Biofuels 2013)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The relationship between seasonal temperatures, organic loading rate (OLR) and the structure of archaeal communities in anaerobic digesters was investigated. Previous studies have often assessed archaeal community structure at fixed temperatures and constant OLRs, or at variable temperatures not characteristic of temperate climates. The goal of this study was to determine the maximum OLR that would maintain a balanced microbial ecosystem during operation in a variable temperature range expected in a temperate climate (27–10 °C). Four-liter laboratory digesters were operated in a semi-continuous mode using dairy cow manure as the feedstock. At OLRs of 1.8 and 0.8 kg VS/m3·day the digesters soured (pH < 6.5) as a result of a decrease in temperature. The structure of the archaeal community in the sour digesters became increasingly similar to the manure feedstock with gains in the relative abundance of hydrogenotrophic methanogens. At an OLR of 0.3 kg VS/m3·day the digesters did not sour, but the archaeal community was primarily hydrogenotrophic methanogens. Recommendations for operating an ambient temperature digester year round in a temperate climate are to reduce the OLR to at least 0.3 kg VS/m3·day in colder temperatures to prevent a shift to the microbial community associated with the sour digesters.
Keywords: anaerobic digestion; archaeal communities; temperature; organic loading rate; terminal restriction fragment length polymorphisms (T-RFLP)
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MDPI and ACS Style

Ciotola, R.J.; Martin, J.F.; Tamkin, A.; Castańo, J.M.; Rosenblum, J.; Bisesi, M.S.; Lee, J. The Influence of Loading Rate and Variable Temperatures on Microbial Communities in Anaerobic Digesters. Energies 2014, 7, 785-803.

AMA Style

Ciotola RJ, Martin JF, Tamkin A, Castańo JM, Rosenblum J, Bisesi MS, Lee J. The Influence of Loading Rate and Variable Temperatures on Microbial Communities in Anaerobic Digesters. Energies. 2014; 7(2):785-803.

Chicago/Turabian Style

Ciotola, Richard J.; Martin, Jay F.; Tamkin, Abigail; Castańo, Juan M.; Rosenblum, James; Bisesi, Michael S.; Lee, Jiyoung. 2014. "The Influence of Loading Rate and Variable Temperatures on Microbial Communities in Anaerobic Digesters." Energies 7, no. 2: 785-803.

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