Measure of Biochemical Methane Potential (BMP) of by-products, residues and alternative crops typical of the Mediterranean area

Conference

Eco-innovative Solutions for Mediterranean Wastes and Wastewate rs

November 8^th, 2014

Measure of Biochemical Methane Potential (BMP) of by-products, residues and alternative crops typical of the Mediterranean area

M. Soldano, L. Rossi, N. Labartino, C. Fabbri, S. Piccinini

Centro Ricerche Produzioni Animali – CRPA Lab Reggio Emilia

products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Introduction

In the Mediterranean area, where the number of biogas plants

is increasing due to the greatest interest on anaerobic

digestion, the agro-industrial activities produce large amounts

of by-products and residues, which are partially or totally

unexploited and in some case represent significant

environmental problem.

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

By-products, residues and alternative crops typical of the

Mediterranean area, potentially usable in anaerobic digestion.

Some examples…

Citrus pulp

Grape stalks Tobacco

Tomate peel Arundo donax

Forages (pellet)

Biogas plant

Olive pomace

products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Anaerobic digestion plant has its own equilibrium depending on the type of biomass loaded and the plant/process parameters adopted.

The knowledge of the Biochemical Methane Potential (BMP) is the basic element for feasibility study and the construction of AD plant.

Biomass have its own molecular composition and a maximum potential production; it is important and necessary, in addition to knowledge of material properties, the assessment of their quality through the analysis of chemical compounds and the measure of methane potential (BMP test) .

BMP– Biochemical Methane Potential

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

CRPA Lab

(more then 1200 BMP test )

- UNI EN ISO 11734:2004 - Manometric system

- 48 batch reactors (total volume 2,2 litre - useful 1,35 dm³)

Parameters test:

• SV inoculum:SV substrate ratio = 2

• Temperature 38 ± 0,2°C

• pH buffered

This parameter expresses the biogas/biomethane potentially available from the degradation of a biomass. It is expressed in Nm³·kgVS^-1 (volatil solid or organic matter).

BMP– Biochemical Methane Potential

BMP static system (in batch)

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

K_max: the time taken to achieve the maximum production speed (days)

F_max: the maximum anaerobic degradability (%)

F_50%: time taken to achieve 50% of the biogas production (days)

F_90%: time taken to achieve 90% of the biogas production (days)

Biogas yield:

Nm³/ton VS o Nm³/ton f.m.

Methane yield:

Nm³/ton VS o Nm³/ton f.m.

Methane percentage: %

Volatile solids degradability: %

BMP: Informations

obtained

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

BMP and chemical analysis: why evaluate them...

To...

• quantify the biomass needed;

• verify compatibility with the type of plant and

farm structures (storages, mix system, hydraulic retention time....);

• quantify digestate to manage;

• quantify nitrogen to manage;

• calculate biomethane production costs.

products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Chemical analysis of some biomass potentially usable in AD plants

Biomass

Total solid

(TS) Volatile solid Total Nitrogen g ·kg^-1 g ·kg^-1 % TS mg ·kg^-1 % TS

“Alternative” crop

Arundo donax silage 301.2 272.7 90.5% 3838 1.3%

Arundo donax 314.5 282.5 89.8% 3860 1.2%

Tobacco 175.8 148.2 84.3% 6577 3.7%

Forage (pellet) 910.5 788.6 86.6% - -

By-products and residues

Processing olive residues 376.7 317.9 84.4% - -

Oil mill wastewater 50.3 39.2 78.0% 1396 2.8%

Tomato peels 234.7 224.9 95.8% 7787 3.3%

Olive pomace – phase 2 360.3 334.8 92.9% 5702 1.6%

Olive pomace – phase 3 256.8 236.7 92.2% 4298 1.7%

Rapeseed cake 880.1 828.5 94.1% 51443 5.8%

Grape stalks 213.0 198.6 93.2% 3032 1.4%

Cotton seeds 940.2 903.4 96.1% 32197 3.4%

Citrus pulp 149.8 137.1 91.5% 2020 1.3%

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

BMP results of some biomass: methane yield and percentage in biogas

(*)Total solids= 32,7%, Volatile solids= 96,3% TS f.m. = fresh matter

Biomass BMP

Nm³CH₄ ·t VS^-1 Nm³CH₄·t fm^-1 CH₄ %

“Alternative” crop

Arundo donax silage 271.4 74.0 54.6%

Arundo donax 234.4 66.2 53.6%

Tobacco 206.0 30.5 62.8%

Forage (pellet) 257.2 202.8 52.9%

By-products and residues

Processing olive residues 165.4 52.6 56.2%

Oil mill wastewater 389.3 15.3 60.6%

Tomato peels 259.3 58.3 56.7%

Olive pomace – phase 2 193.0 64.6 66.8%

Olive pomace – phase 3 201.1 47.6 69.2%

Rapeseed cake 382.3 316.8 62.9%

Grape stalks 60.8 12.1 56.0%

Cotton seeds 298.7 269.9 63.0%

Citrus pulp 276.8 38.0 50.2%

Mais silage ^(*) 351.5 110.6 53.0%

products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Cumulative methane yields (30 days) of

some crops

Measure of BMP of by- products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Cumulative methane yields (30 days) of

some biomass

products, residues and alternative crops typical of the

Mediterranean area

Ecomondo - 2014 Rimini, November 8°, 2014

Conclusion

Biogas yield of “alternative” crops, obtained by BMP test are high, although lower than the average value of a standard maize silage;

agro-industrial biomass, such as tomato peels, citrus pulp, oil pomace have good methane yields, but also a fair share of low degradability solid whose use in anaerobic digestion may determine an increase of the concentration of dry substance in the digesters;

the biogas production of these matrices can also increase the methane potential of small anaerobic digestion plants, that usually use only livestock effluent, and decrease the use of dedicated energy crops in large plants.

Conference

Eco-innovative Solutions for Mediterranean Wastes and Wastewate rs

November 8^th, 2014

www.crpa .it http://crpalab.crpa.it m.soldano@crpa.it

Thanks for your attention