Enhancing the co-digestion efficiency of sewage sludge and cheese whey using brewery spent grain as an additional substrate

The influence of two pretreatment methods, thermal treatment and low-pressure wet oxidation, on the sludge digestion efficiency was examined. Batch thermophilic anaerobic digestion was used to evaluate the effectiveness of the pretreatment methods in terms of volatile suspended solids (VSS) digestion efficiency and gas production. The results showed that the gas production was not proportional to the VSS degradation efficiency of either thermal treatment or low-pressure wet oxidation. Low-pressure wet oxidation treatment at 150 °C along with 40% of the theoretical oxygen required to oxidize organic carbon gave the highest gas production and the VSS digestion efficiency of 77% at a VSS loading rate of 8 g l−1 d−1. The digestion efficiency was about 30% higher than that of thermophilic anaerobic digestion without sludge pretreatment. Sewage sludge could be treated effectively at a high VSS digestion efficiency with this pretreatment followed by thermophilic anaerobic digestion.

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Treatment of dairy waste by anaerobic co-digestion with sewage sludge

Ecological Chemistry and Engineering S ◽

10.1515/eces-2016-0007 ◽

2016 ◽

Vol 23 (1) ◽

pp. 99-115 ◽

Cited By ~ 5

Author(s):

Agnieszka A. Pilarska ◽

Krzysztof Pilarski ◽

Kamil Witaszek ◽

Hanna Waliszewska ◽

Magdalena Zborowska ◽

...

Keyword(s):

Lactic Acid ◽

Anaerobic Digestion ◽

Sewage Sludge ◽

Organic Carbon ◽

Organic Waste ◽

Cheese Whey ◽

Oxygen Demand ◽

Volatile Solids ◽

Biomethane Production ◽

Digested Sewage Sludge

Abstract The results of anaerobic digestion (AD) of buttermilk (BM) and cheese whey (CW) with a digested sewage sludge as inoculum is described. The substrate/inoculum mixtures were prepared using 10% buttermilk and 15% cheese whey. The essential parameters of the materials were described, including: total solids (TS), volatile solids (VS), pH, conductivity, C/N ratio (the quantitative ratio of organic carbon (C) to nitrogen (N)), alkalinity, chemical oxygen demand (COD). The potential directions of biodegradation of the organic waste types, as used in this study, are also presented. Appropriate chemical reactions illustrate the substrates and products in each phase of anaerobic decomposition of the compounds that are present in buttermilk and cheese whey: lactic acid, lactose, fat, and casein. Moreover, the biogas and biomethane production rates are compared for the substrates used in the experiment. The results have shown that buttermilk in AD generates more biogas (743 m3/Mg VS), including methane (527 m3/Mg VS), when compared with cheese whey (600 m3/Mg VS, 338 m3/Mg VS for biogas and methane, respectively).

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Potentials and limits of anaerobic digestion of sewage sludge: Energy self-sufficient municipal wastewater treatment plant?

Water Science & Technology ◽

10.2166/wst.2012.317 ◽

2012 ◽

Vol 66 (6) ◽

pp. 1277-1281 ◽

Cited By ~ 38

Author(s):

P. Jenicek ◽

J. Bartacek ◽

J. Kutil ◽

J. Zabranska ◽

M. Dohanyos

Keyword(s):

Wastewater Treatment ◽

Energy Consumption ◽

Anaerobic Digestion ◽

Sewage Sludge ◽

Wastewater Treatment Plant ◽

Municipal Wastewater ◽

Biogas Production ◽

Treatment Plant ◽

Self Sufficiency ◽

Digestion Efficiency

Anaerobic digestion is the only energy-positive technology widely used in wastewater treatment. Full-scale data prove that the anaerobic digestion of sewage sludge can produce biogas that covers a substantial amount of the energy consumption of a wastewater treatment plant (WWTP). In this paper, we discuss possibilities for improving the digestion efficiency and biogas production from sewage sludge. Typical specific energy consumptions of municipal WWTPs per population equivalent are compared with the potential specific production of biogas to find the required/optimal digestion efficiency. Examples of technological measures to achieve such efficiency are presented. Our findings show that even a municipal WWTP with secondary biological treatment located in a moderate climate can come close to energy self-sufficiency. However, they also show that such self-sufficiency is dependent on: (i) the strict optimization of the total energy consumption of the plant, and (ii) an increase in the specific biogas production from sewage sludge to values around 600 L per kg of supplied volatile solids.

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