Enhanced Biogas Production in Pilot Digesters Treating a Mixture of Olive Mill Wastewater and Agro-industrial or Agro-livestock By-Products in Greece

Experimental trials of anaerobic digestion of olive mill wastewater (OMW) blended with other agro-industrial by-products were carried out to evaluate biogas production and sensitivity of the process to inhibiting compounds. Blends containing different percentages of OMW, digested liquid manure, and citrus peel were subjected to a batch anaerobic digestion process under both mesophilic and thermophilic conditions. The results showed that blends with percentages of OMW higher than 20% (v/v) had low methane yields due high concentrations of polyphenols (PPs) and/or volatile fatty acids (concentrations above 0.8 g kg–1 and 2.4 g L–1, respectively). The addition of other substrates such as citrus peel may have induced synergic inhibiting effects of PPs and essential oils (EO) on microbial growth. Thermophilic processes were more sensitive to these inhibiting compounds than mesophilic processes. The results of this study suggest that reducing PPs and EO concentrations in blends subject to anaerobic digestion below the inhibiting concentrations of 0.6 g L–1 and 0.5 g kg–1, respectively, is suitable. Additionally, it is advisable to maintain the volatile fatty acids content below 2 g L–1 to avoid its evident toxic effects on the growth of microorganisms in biochemical processes.

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Anaerobic Co-Digestion of Pig and Cow Manure with a Solar Dried Mixture of Food Waste and Olive Mill Wastewater

Proceedings ◽

10.3390/proceedings2019030091 ◽

2020 ◽

Vol 30 (1) ◽

pp. 91

Author(s):

Nikolaos Papastefanakis ◽

Chryssa Bouki ◽

Michail S. Fountoulakis ◽

Christos Tsompanidis ◽

Theofanis Lolos ◽

...

Keyword(s):

Food Waste ◽

Biogas Production ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Olive Mill Wastewater ◽

Anaerobic Sludge ◽

Cow Manure ◽

Drying Process ◽

Working Volume ◽

Olive Mill

Biogas production through anaerobic digestion is a well-established practice worldwide combining waste treatment and energy production at the same time. One of the challenges of this technology is to increase the yield of biogas production and secure the disposal of the effluent of anaerobic reactors. It is well known that various organic residues such as cheese whey, olive mill wastewater, as well as food waste from hotel units, could be combined with other materials (animal manures, sewage sludge, etc.) in order to increase biogas production through co-digestion. However, their high seasonal variation and high transport costs is a barrier for their use. Solar drying process can be a very attractive technology for volume reduction in order to decrease the storage and the transportation cost. Moreover using solar energy may well be an alternative solution for reduction of drying process costs. In this study, co-digestion of pig manure (PM) and cow manure (CM) with solar dried mixture of food waste (FW) and olive mill wastewater (OMW), named as biobooster, was studied in an attempt to improve biogas production of existing on—farms plants which co-digest manure with other farm waste. The effect of biobooster in biogas production was investigated using three lab-scale continuous stirred-tank reactors (CSTR) (3 L working volume) (D1–D3) under mesophilic conditions (37 ± 2 °C) with a hydraulic retention time of 20 days. Initially, all reactors were inoculated with anaerobic sludge originating from sewage treatment plant of the city of Heraklion, and contained 19.6 g/L TS, 10.8 g/L VS and 17.5 g/L COD. Three types of influent feedstock were utilized: D1: PM (95%) + CM (5%) (VSin = 33.58 ± 4.51 g/L), D2: PM (95%) + CM (5%) + Biobooster (1%) (VSin = 41.07 ± 7.16 g/L), D3: PM (100%) + Biobooster (1%) (VSin = 8.48 ± 0.87 g/L). The experiments showed that the addition of biobooster to pig and cow manure significantly increased biogas production by nearly 65% as value of 662.75 ± 172.50 mL/l/d compared to that with pig and cow manure alone (402.60 ± 131.89 mL/l/d). The biogas production in D3 reactor was 242.50 ± 56.82 mL/l/d. This work suggests that methane can be improved very efficiently by adding a small portion (20% increase of VS) of dried agro-industrial by-products in the inlet of digesters of existing on—farms plants.

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Anaerobic waste activated sludge co-digestion with olive mill wastewater

Water Science & Technology ◽

10.2166/wst.2012.139 ◽

2012 ◽

Vol 65 (12) ◽

pp. 2251-2257 ◽

Cited By ~ 18

Author(s):

E. Athanasoulia ◽

P. Melidis ◽

A. Aivasidis

Keyword(s):

Activated Sludge ◽

Biogas Production ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

System Stability ◽

Waste Activated Sludge ◽

Loading Rates ◽

Soluble Chemical Oxygen Demand ◽

Continuous Stirred Tank ◽

Olive Mill

Co-digestion of waste activated sludge (WAS) with agro-industrial organic wastewaters is a technology that is increasingly being applied in order to produce increased gas yield from the biomass. In this study, the effect of olive mill wastewater (OMW) on the performance of a cascade of two anaerobic continuous stirred tank (CSTR) reactors treating thickened WAS at mesophilic conditions was investigated. The objectives of this work were (a) to evaluate the use of OMW as a co-substrate to improve biogas production, (b) to determine the optimum hydraulic retention time that provides an optimised biodegradation rate or methane production, and (c) to study the system stability after OMW addition in sewage sludge. The biogas production rate at steady state conditions reached 0.73, 0.63, 0.56 and 0.46 lbiogas/lreactor/d for hydraulic retention times (HRTs) of 12.3, 14, 16.4 and 19.7 d. The average removal of soluble chemical oxygen demand (sCOD) ranged between 64 and 72% for organic loading rates between 0.49 and 0.75 g sCOD/l/d. Reduction in the volatile suspended solids ranged between 27 and 30%. In terms of biogas selectivity, values of 0.6 lbiogas/g tCOD removed and 1.1 lbiogas/g TVS removed were measured.

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Exploitation of olive mill wastewater and liquid cow manure for biogas production

Waste Management ◽

10.1016/j.wasman.2010.02.035 ◽

2010 ◽

Vol 30 (10) ◽

pp. 1841-1848 ◽

Cited By ~ 39

Author(s):

Margarita A. Dareioti ◽

Spyros N. Dokianakis ◽

Katerina Stamatelatou ◽

Constantina Zafiri ◽

Michael Kornaros

Keyword(s):

Biogas Production ◽

Olive Mill Wastewater ◽

Cow Manure ◽

Olive Mill

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Effect of acclimatization factors on reproducibility of biogas production in anaerobic cultures from electrochemically pre-treated or filtered olive mill wastewater

Desalination and Water Treatment ◽

10.5004/dwt.2010.2085 ◽

2010 ◽

Vol 23 (1-3) ◽

pp. 206-213 ◽

Cited By ~ 2

Author(s):

Maria Patoni ◽

Nicolas Kalogerakis

Keyword(s):

Biogas Production ◽

Olive Mill Wastewater ◽

Olive Mill

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Effect of acclimatization factors on reproducibility of biogas production in anaerobic cultures from electrochemically pre-treated or filtered olive mill wastewater

10.5004/dwt.2010.2088 ◽

2010 ◽

pp. 206-213

Author(s):

Maria Patoni ◽

Nicolas Kalogerakis

Keyword(s):

Biogas Production ◽

Olive Mill Wastewater ◽

Olive Mill

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Influence of the heavy metals concentration on the anaerobic co-digestion performance of activated sludge and Olive mill wastewater

10.21203/rs.3.rs-761999/v1 ◽

2021 ◽

Author(s):

khalideh Al bkoor Alrawashdeh

Keyword(s):

Heavy Metals ◽

Activated Sludge ◽

Removal Efficiency ◽

Biogas Production ◽

Olive Mill Wastewater ◽

Organic Load ◽

High Concentration ◽

Digestion Process ◽

The Impact ◽

Olive Mill

Abstract The influence of heavy metals (HMs) on the anaerobic co-digestion process (AD) of activated sludge and olive mill wastewater (50% v/v) was studied. Biogas production, methane CH4 concentration, and removal efficiency of the TS, VS, and TCOD were investigated in mesophilic conditions. The toxicity and inhibitory effects of HMs at different concentrations (15–60 ppm) on the digestion process were specified.A high concentration of HMs has resulted in a significant decrease in AD performance in terms of organic load degradation, biogas production, CH4 content, TCOD removal efficiency, and inhibition of hydrogenotrophic-methanogenic bacteria. The toxicity of HMs can be arranged according to TS removal: Cu > Zn ≈ Cr > Pb, according to TCOD removal efficiency: Cu > Cr > Zn > Pb, biogas production: Cu > Zn ≈ Cr > Pb, CH4 content: Cu > Zn > Cr > Pb. Also, the results showed that the methanogenic stage was influenced negatively and more than the acetogenic stage, where Pb < 30 ppm had a lower inhibitor effect on the digestion, while the lowest concentration of Cu(II) leads to the significant inhibition of the AD process is ≥ 10 ppm. At the concentration of 60 ppm of Pb, Zn, Cr, and Cu, the COD removal efficiency was 17.07%, 15.64%, 19.13%, and 20.53% respectively, TS removal was 17.31%, 13.44%, 16.28%, and 10.37 respectively, the VS removal was 19.4%, 14.445, 7.94% and 5.17%, respectively. Also, at the concentration of 60 ppm, biogas production has decreased by 51.55%, 66.46%, 68.1%, and 73.91%, respectively.Novelty statement This study provides new data specifying the inhibitor HMs concentration and the impact of HMs at the various concentrations on the anaerobic co-digestion of active sludge and olive mill wastewater

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